AeroElectric-Archive.digest.vol-cy
February 24, 2004 - March 03, 2004
Trimmed for 90 mph.
Traveling Down at 40 degrees: 3.4a
Traveling Up at 40 degrees: .7a
Switch held in Up position with flaps Up in flight (motor freewheeling) 1.3a
(don't know why this is different than when sitting on ground)
One interesting thing I did notice was that when fully extending the flaps at
80-90mph to the point that the motor was freewheeling, or about 43 degrees on
my plane, the current would rise continuously until the end of travel, going
just over 5a at full extension, then as the motor began to freewheel, the
current dropped to 1.2 until I released the switch- not sure how the actuator is
constructed, but the air load is obviously not held by motor power alone...
Flaps performed flawlessly throughout this regimen, as did the rest of the
plane (omigawd what an awesome machine! - can you tell I like it?!) Now here's
the clincher. I had a little time to kill before dark and did some T&G's. The
first was pretty darn acceptable, flaps raised before taking off again and
extended normally on approach. On the second T&G I let the bottom fall out a
few feet up and got a bounce. Again raised the flaps before taking off, all is
normal. On downwind I hit the flap switch at 100 mph and NOTHING! Fuse blown
again! Same as both times before. Open for all ideas at this point!
Mark Phillips - N51PW - ONLY 1.9 HOURS TIL I GET OUT OF MY CAGE!!!!! 8-)
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> batteries |
Subject: | Essential bus alternate feed from two |
batteries
batteries
>
>The reason I went with two batteries is two fold. First, I have one mag
>and one electronic ignition (not a electrically dependant engine).
which by itself is not a driver for dual batteries
>During start I thought I would use the main battery for cranking engine,
>the aux battery for powering the electronic ignition (to avoid any
>possibility of kick back in the event main battery voltage drops below
>min required for electronic ignition).
???? Is it the stated policy/recommendation by the manufacturer
of the ignition system that you do this? I'm increasingly mystified
by what I perceive as an upsurge in worries about this. Perhaps
it's just that the economy is improving and more folks are building
airplanes with electronic ignition. Market forces notwithstanding,
I'm wondering if the risk is real and whether or not the manufacturers
of these products are acknowledging a shortcoming in their product's
design. The low voltage event during cranking is tens of milliseconds
long as the starter motor spins up. There is no good reason why
you as the user should have to be concerned about this. Designing
sensitivity to this phenomenon out of the ignition system is
a rudimentary technique of circuit design.
> The second reason is your
>recommended battery replacement plan of once a year, I will always have
>one new battery and one no more than two years old. So with that said,
>don't you agree that having the ability to use both batteries to power
>the essential bus to is a good idea? If so, is the solution a 2-10
>switch?
Dual, rotated batteries implies two batteries of the same
size. My personal favorite is the 17 a.h. VSLA/RG battery
at 15 or so pounds. If you're willing to carry a 15# "penalty"
for the value of improved battery performance, perhaps this
no big deal. You'll have a wealth of capacity aboard that
would allow you to close both battery contactors should
you find that the main battery is over-taxed during alternator
out ops.
Obviously, you could use a 2-10 to tap either battery for
e-bus support . . . but I think there is value in thinking
through the requirement for dual batteries . . .
Your wife may wish that the airplane had 15# more payload
to bring home souvenirs of that trip to the Bahamas.
Bob . . .
________________________________________________________________________________
From: | "George Braly" <gwbraly(at)gami.com> |
Bob, I have not tried to measure the energy in the load dump event. When I started
observing some component damage, I started to try to control it. This
was with an alternator pulling about 35 to 40 amps.
I tried the easy stuff first, and the 5KWatt TVS device was my second effort after
the 1.5K.
Regards, George
[PS... Bob, this is being sent as plaint text instead of HTML... should stop
the gibberish from the last message.]
>
>
>Bob,
>
>I have done a fair amount of testing a couple of years ago, working with the
>TVS devices, including the larger sized versions.
>
>In my experience, they have not been adequate, alone, to prevent over
>voltage spikes on load dumps, even from smaller alternators.
>
>They help. But I have blown some of them on load dumps.
Have you taken any energy measurements on the load (battery)-dump
phenomenon?
Bob . . .
---
________________________________________________________________________________
From: | "Cy Galley" <cgalley(at)qcbc.org> |
Subject: | Re: Flap motor testing |
If you are having a fuse problem because of a temporary surge, wouldn't a
slo-blow fuse be in order?
----- Original Message -----
From: <Fiveonepw(at)aol.com>
Subject: AeroElectric-List: Flap motor testing
>
> Thanks to all for your thoughts on the flap fuse failure fiasco- lot's of
> good info... The following is long, tedious and boring (unless you're an
> electrical masochist!) so delete now if so inclined............
>
> Test results using Fluke 87 MM (10 amps max. current) connected at fuse
> block. Flap motor (motion brand) is wired direct through a quality NKK
DPDT switch
> of the proper rating (no relays) using 18ga. My meter does have an
"analog"
> scale along the bottom of the display that responds very quickly, and it
did
> go off-scale the instant the switch is first turned on indicating over 10a
on
> start. This was also confirmed (If I did it correctly) by the min/max
function
> that records for 100 msec. which indicated "OL" or "out of range" for the
> instrument. This confirms Bob's statement about inrush current. Below
are my
> readings, as best as I could tell while watching altimeter, airspeed, MM,
and an
> occasional glance for traffic (darn, no dang "required crew member"!)
This
> is all done with 10 amp fuse installed.
>
> On the ground, engine off- cycled flaps repeatedly in both directions
trying
> to get a failure. Even held switch after full travel many times for as
much
> as 5 seconds with motor freewheeling, no failure, up or down.
>
> Traveling Down: .8a
> Freewheeling Down: 1.9a
> Traveling Up: .9a
> Freewheeling Up: 1.7a
>
> (anyone know if this would indicate that the motion actuator has a a
friction
> clutch in it?)
>
> Same values with engine running (LVWM off) at idle.
>
> Tested again at runup (1700 rpm) and Down required .9 indicating harder
work
> against propwash. Up netted .8 for same reason- looks like we're getting
good
> data...
>
> Climbed to 3000', trimmed for 100 mph indicated. Naturally these readings
> are dynamic as the flaps change angle and airspeed falls, and the meter
display
> lags a little, but after repeated attempts, the values are as close as I
could
> get them by timing the extension/retraction - I'd release the switch while
> watching the meter and verify flap had stopped at proper position- if not,
I'd
> re-do it. (again, no extra crewman!)
>
> Traveling Down at 20 degrees: 2.0a
> Traveling Up at 20 degrees: .7a
>
> Trimmed for 90 mph.
>
> Traveling Down at 40 degrees: 3.4a
> Traveling Up at 40 degrees: .7a
>
> Switch held in Up position with flaps Up in flight (motor freewheeling)
1.3a
> (don't know why this is different than when sitting on ground)
>
> One interesting thing I did notice was that when fully extending the flaps
at
> 80-90mph to the point that the motor was freewheeling, or about 43 degrees
on
> my plane, the current would rise continuously until the end of travel,
going
> just over 5a at full extension, then as the motor began to freewheel, the
> current dropped to 1.2 until I released the switch- not sure how the
actuator is
> constructed, but the air load is obviously not held by motor power
alone...
>
> Flaps performed flawlessly throughout this regimen, as did the rest of the
> plane (omigawd what an awesome machine! - can you tell I like it?!) Now
here's
> the clincher. I had a little time to kill before dark and did some T&G's.
The
> first was pretty darn acceptable, flaps raised before taking off again and
> extended normally on approach. On the second T&G I let the bottom fall
out a
> few feet up and got a bounce. Again raised the flaps before taking off,
all is
> normal. On downwind I hit the flap switch at 100 mph and NOTHING! Fuse
blown
> again! Same as both times before. Open for all ideas at this point!
>
> Mark Phillips - N51PW - ONLY 1.9 HOURS TIL I GET OUT OF MY CAGE!!!!! 8-)
>
>
________________________________________________________________________________
From: | "Ron Raby" <ronr(at)advanceddesign.com> |
To everyone:
I am planning a blue metalic finish on the bottom of my plane. I was
wondering if this will have an effect on the antenna's I have mounted on the
inside? transponder, Nav and I have a com antenna mounted on the side, where
the #s are. The N #s are also the blue metalic finish.
Thanks
Ron Raby
Lancair ES
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
Subject: | Re: Pass during flight test |
Yes I have read that AC and the Local FAA flight standards office said such
permission was extremely unlikely to be allowed (never done here per the
rep) as they see no reason why audio and/or video cameras will not do a
better job etc etc. You would need to justify why other recording methods
cannot be used and also that the measurements must be made during the
initial testing phase. Cost is not generally a valid reason for a second
person.
But your point is well taken. However you will need a specific written
exception as AC 20-27F states.
In addition permission from your insurance Co will also be needed (assuming
you have insurance) as normally more than one in the fly off phase will
invalidate your insurance even if you have FAA approval.
Thus its possible in theory to get both written permission and insurance Co
permission for a second person for a specific flight test.
The FAA's general position as told to me is they have never given permission
and see no need to do so for SEL experimental acft during initial flight
test period.
Personally I use a video camera mounted to view the panel and the audio tied
into the intercom.
Paul
----- Original Message -----
From: "Terry Watson" <terry(at)tcwatson.com>
Subject: RE: AeroElectric-List: Flap motor overload?
>
> Here's what Advisory Circular 20-27F, Certification and Operation of
Amateur
> Built Aircraft says about it taking someone along during the flight test
> period:
>
> 13. PHASE 1 FLIGHT TESTING.
> e. Restrictions
> (1) Carrying Passengers. You may not carry passengers while you are
> restricted to the flight test area or during any portion of your Phase I
> flight test program. We suggest you use a tape or video recorder for
> recording readings and other similar tasks. If you need an additional
> crewmember for a particular flight test, specify that in your application
> program letter for the airworthiness certificate. We will list this need
in
> your operating limitations.
> (2) Flight Instruction. You may not receive flight instruction during
your
> flight test.
>
> Terry
>
________________________________________________________________________________
From: | "Ron Lee" <rlee468(at)comcast.net> |
A couple of us older guys without perfect hearing (high range) have had to return
ANR headsets because we couldn't hear well on them. The problem is the audio
is very bass and little treble, kind of like the person on the other end is
on a distant speaker phone. We hear ok on standard headsets but wanted the ANR
to preserve our hearing. The question is, is this normal or have we each gotten
bad brands?
________________________________________________________________________________
Subject: | Re: ANR headsets |
From: | "Matt Prather" <mprather(at)spro.net> |
I used the "headsets inc." ANR conversion kit for my flightcom
cheapies. The modules that are included replace the speakers
(transducers) in each ear cup. The sound quality with this
kit is far better and more intelligible than was the original
(admittadly, cheap) setup. I don't see any reason why an ANR
system would change the tonal balance of sounds being
reproduced.
Matt-
VE N34RD
>
> A couple of us older guys without perfect hearing (high range) have had
> to return ANR headsets because we couldn't hear well on them. The
> problem is the audio is very bass and little treble, kind of like the
> person on the other end is on a distant speaker phone. We hear ok on
> standard headsets but wanted the ANR to preserve our hearing. The
> question is, is this normal or have we each gotten bad brands?
>
>
________________________________________________________________________________
From: | F1Rocket(at)comcast.net |
Subject: | Re: metalic paint |
My RV-6 has dark blue metallic on the bottom with a lighter blue metallic above
on white. No problems at all with any of the antennas (all on the bottom).
Randy
F1 Rocket
http://f1rocket.home.comcast.net/
>
>
> To everyone:
>
> I am planning a blue metalic finish on the bottom of my plane. I was
> wondering if this will have an effect on the antenna's I have mounted on the
> inside? transponder, Nav and I have a com antenna mounted on the side, where
> the #s are. The N #s are also the blue metalic finish.
>
> Thanks
>
> Ron Raby
>
> Lancair ES
>
>
>
>
>
>
________________________________________________________________________________
Subject: | Essential bus alternate feed from two batteries |
From: | "George Braly" <gwbraly(at)gami.com> |
>>There is no good reason why
you as the user should have to be concerned about this. Designing
sensitivity to this phenomenon out of the ignition system is
a rudimentary technique of circuit design.<<
Amen.
---
________________________________________________________________________________
From: | "Ron Raby" <ronr(at)advanceddesign.com> |
Subject: | Re: metalic paint |
Randy
My antenna's are mounted on the inside shooting through the fiberglass. I am
assuming on an RV6 that the antenna's are on the outside of the plane and
paint.?
Thanks
Ron Raby
----- Original Message -----
From: <F1Rocket(at)comcast.net>
Subject: Re: AeroElectric-List: metalic paint
>
> My RV-6 has dark blue metallic on the bottom with a lighter blue metallic
above on white. No problems at all with any of the antennas (all on the
bottom).
>
> Randy
> F1 Rocket
> http://f1rocket.home.comcast.net/
> >
> >
> > To everyone:
> >
> > I am planning a blue metalic finish on the bottom of my plane. I was
> > wondering if this will have an effect on the antenna's I have mounted on
the
> > inside? transponder, Nav and I have a com antenna mounted on the side,
where
> > the #s are. The N #s are also the blue metalic finish.
> >
> > Thanks
> >
> > Ron Raby
> >
> > Lancair ES
> >
> >
> >
> >
> >
> >
>
>
________________________________________________________________________________
From: | "David Carter" <dcarter(at)datarecall.net> |
Subject: | Re: Two alternators-using total rated combined output |
Phil, thanks - I like that - is intuitively simple and sound.
Are you building at DW Hooks Airport or at home? I'm over in Nederland (by
Beaumont) and go to Houston frequently.
David
409-722-7259
----- Original Message -----
From: "Phil Birkelbach" <phil(at)petrasoft.net>
Subject: Re: AeroElectric-List: Two alternators-using total rated combined
output
>
>
> > - What is the "simplest" way to a) have the two identical
regulators
> > and alternators each share roughly 1/2 of the load, whatever it is, or,
b)
> > allow 1 alternator to go up to its rated output and then have any
> subsequent
> > increase in load be picked up by the other alternator? Are there other
> > "approaches" to this?
> >
> > David Carter
>
> The simplest way would be to simply split the loads. Have two electrical
> systems. Put Comm 1 on buss 1 and Comm 2 on buss 2, put the taxi light on
> one side the landing light on the other. Two smaller batteries and a
> crossover contactor for starting, and for single alternator operations.
Put
> a load meter on each one so you know what is going on and you've got it.
> This also builds in a level of redundancy. I think Bob has a 2
alternator,
> 2 battery system in the Z diagrams somewhere.
>
> There are probably some voltage regulators out there that can handle the
> load sharing but I doubt that any of it would be 'simple'.
>
> Godspeed,
>
> Phil Birkelbach - Houston Texas
> RV-7 N727WB (Reserved) - Baffles / Cowling
> http://www.myrv7.com
________________________________________________________________________________
From: | "Jeff Hildebrand" <jhildebrand(at)crownequip.com> |
When we planned our metallic paint job, we had the same worries. We
talked to Lancair and they said it was no problem, they have seen many
planes with metallic paint and it was no issue.
Jeff Hildebrand
Lancair ES
http://lancair.northstartraffic.ca
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ron
Raby
Subject: Re: AeroElectric-List: metalic paint
Randy
My antenna's are mounted on the inside shooting through the fiberglass.
I am
assuming on an RV6 that the antenna's are on the outside of the plane
and
paint.?
Thanks
Ron Raby
----- Original Message -----
From: <F1Rocket(at)comcast.net>
Subject: Re: AeroElectric-List: metalic paint
>
> My RV-6 has dark blue metallic on the bottom with a lighter blue
metallic
above on white. No problems at all with any of the antennas (all on the
bottom).
>
> Randy
> F1 Rocket
> http://f1rocket.home.comcast.net/
> >
> >
> > To everyone:
> >
> > I am planning a blue metalic finish on the bottom of my plane. I was
> > wondering if this will have an effect on the antenna's I have
mounted on
the
> > inside? transponder, Nav and I have a com antenna mounted on the
side,
where
> > the #s are. The N #s are also the blue metalic finish.
> >
> > Thanks
> >
> > Ron Raby
> >
> > Lancair ES
> >
> >
> >
> >
> >
> >
>
>
==
==
==
==
________________________________________________________________________________
From: | F1Rocket(at)comcast.net |
Subject: | Re: metalic paint |
Yes. Sorry I missed the distinction on your question.
Randy
>
> Randy
>
> My antenna's are mounted on the inside shooting through the fiberglass. I am
> assuming on an RV6 that the antenna's are on the outside of the plane and
> paint.?
>
> Thanks
>
> Ron Raby
> ----- Original Message -----
> From: <F1Rocket(at)comcast.net>
> To:
> Subject: Re: AeroElectric-List: metalic paint
>
>
> >
> > My RV-6 has dark blue metallic on the bottom with a lighter blue metallic
> above on white. No problems at all with any of the antennas (all on the
> bottom).
> >
> > Randy
> > F1 Rocket
> > http://f1rocket.home.comcast.net/
>
> > >
> > >
> > > To everyone:
> > >
> > > I am planning a blue metalic finish on the bottom of my plane. I was
> > > wondering if this will have an effect on the antenna's I have mounted on
> the
> > > inside? transponder, Nav and I have a com antenna mounted on the side,
> where
> > > the #s are. The N #s are also the blue metalic finish.
> > >
> > > Thanks
> > >
> > > Ron Raby
> > >
> > > Lancair ES
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
>
>
>
>
>
>
________________________________________________________________________________
From: | Fiveonepw(at)aol.com |
Subject: | Re: Flap motor testing |
In a message dated 2/24/04 10:11:33 AM Central Standard Time,
cgalley(at)qcbc.org writes:
> If you are having a fuse problem because of a temporary surge, wouldn't a
> slo-blow fuse be in order?
It has only happened when least loaded- still suspect a short, somehow
related to harder than normal landings each time- will have to pull floorboards
to
inspect all wiring, but this still doesn't explain why the flaps get all the
way up, and then when I need them again find the fuse is blown. For all I know,
they "could" be blowing when I first touch the switch after power ruduction
on downwind- (see note on Lancair at bottom)
>> Is the fuse cartridge a SLO-BLOW or a standard link type?
ATC fuse in B&C fuseblock
A Lancair driver here says he was popping breakers when his engine (Engineair
V-8) was idling due to alternator turning very slowly (normal operating rpm
for this monster is WAY above 2700!) and voltage was very low from other loads-
"less volts=more current"(?) Suggested that raising flaps with engine idling
(voltage low) would make current go up resulting in blow, but I never noticed
a LV alert from the EIS or LVWM- anyone else heard this theory? It doesn't
sit well with my prior agreements with Mr. Ohm...
I think the next step is to rig a test lamp to the fuseblock output faston so
I know exactly WHEN the little wire goes "poof!"
Mark
________________________________________________________________________________
From: | "Dan Branstrom" <danbranstrom(at)verizon.net> |
Subject: | Re: Flap motor testing |
still doesn't explain why the flaps get all the
> way up, and then when I need them again find the fuse is blown.
Could there be some problem with the up limit on the flaps when under load?
The stop microswitch relative to the flaps could be positioned differently
in the air and on the ground.
Dan Branstrom
________________________________________________________________________________
From: | Ken Harrill <KHarrill(at)osa.state.sc.us> |
teries
Subject: | Essential bus alternate feed from two bat |
teries
batteries
>During start I thought I would use the main battery for cranking engine,
>the aux battery for powering the electronic ignition (to avoid any
>possibility of kick back in the event main battery voltage drops below
>min required for electronic ignition).
???? Is it the stated policy/recommendation by the manufacturer
of the ignition system that you do this? I'm increasingly mystified
by what I perceive as an upsurge in worries about this. Perhaps
it's just that the economy is improving and more folks are building
airplanes with electronic ignition. Market forces notwithstanding,
I'm wondering if the risk is real and whether or not the manufacturers
of these products are acknowledging a shortcoming in their product's
design. The low voltage event during cranking is tens of milliseconds
long as the starter motor spins up. There is no good reason why
you as the user should have to be concerned about this. Designing
sensitivity to this phenomenon out of the ignition system is
a rudimentary technique of circuit design.
Bob,
This may be a legitimate "worry". I spent quite a bit of time and energy
attempting to resolve the starting problems with my LSE ignition system. I
have a permanent magnet Lycoming starter, a 17 AH battery, and I start the
engine on the electronic ignition only. My engine would only start when I
released the starter button. It always started, but it left me with an
uneasy feeling that sometime, far away from home, it may not. The voltage
(measured at the ignition module) drops to around 8 volts with the starter
engaged, and the LSE does not fire at that voltage, regardless of what
Klause claims. I resolved the problem for now by switching to an Odyssey
battery, which does not produce quite as much voltage drop. A better
solution is a B & C starter that draws less current, but that cost $$$. If
I were building an airplane with two batteries, I would certainly consider
starting on one and powering the electronic ignition from the other.
Ken Harrill
RV-6, 300 hours
________________________________________________________________________________
From: | BobsV35B(at)aol.com |
Subject: | Re: Two alternators-using total rated combined output |
In a message dated 2/24/04 12:04:52 PM Central Standard Time,
phil(at)petrasoft.net writes:
The simplest way would be to simply split the loads. Have two electrical
systems. Put Comm 1 on buss 1 and Comm 2 on buss 2, put the taxi light on
one side the landing light on the other. Two smaller batteries and a
crossover contactor for starting, and for single alternator operations. Put
a load meter on each one so you know what is going on and you've got it.
Good Afternoon Phil,
For What It Is Worth, that is the method used by Beechcraft on the very first
few Twin Beechcrafts built in the middle thirties. The only exception is that
they did not normally tie the batteries together for starting. Each side was
left separated.
There really is very little new under the sun.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
________________________________________________________________________________
From: | "Jim Stone" <jrstone(at)insightbb.com> |
Subject: | Essential bus alternate feed from two batteries |
Bob said:
???? Is it the stated policy/recommendation by the manufacturer
of the ignition system that you do this? I'm increasingly mystified
by what I perceive as an upsurge in worries about this. Perhaps
it's just that the economy is improving and more folks are building
airplanes with electronic ignition. Market forces notwithstanding,
I'm wondering if the risk is real and whether or not the
manufacturers
of these products are acknowledging a shortcoming in their product's
design. The low voltage event during cranking is tens of milliseconds
long as the starter motor spins up. There is no good reason why
you as the user should have to be concerned about this. Designing
sensitivity to this phenomenon out of the ignition system is
a rudimentary technique of circuit design.
Yes it is. I guess this somewhat "rare" problem is occurring due to the
high inrush current that some of the super light starter motors can
draw. Skytec sees the problem on a regular basis in the return of their
units for repair following a kickback. As I mention earlier, if the
conditions are right, i.e., its cold, battery a bit weak or old or both,
and you some how find yourself with less than minimum volts to power the
EI, you may have an expensive repair on your hands. A second battery is
just one way to avoid it.
Dual, rotated batteries implies two batteries of the same
size. My personal favorite is the 17 a.h. VSLA/RG battery
at 15 or so pounds. If you're willing to carry a 15# "penalty"
for the value of improved battery performance, perhaps this
no big deal. You'll have a wealth of capacity aboard that
would allow you to close both battery contactors should
you find that the main battery is over-taxed during alternator
out ops.
I have dual Odyssey 680s 17 ah at 15# each. Most Rockets are a bit nose
heavy so an extra 5# of battery (in the rear) above the designed wt and
balance figure should be a wash between loss of payload and lighter
nose. Since battery power is my only electrical backup and with the
kickback concern and the plan for annual replacement of a battery, it
just all added up to having two identical batteries. Plenty of juice
during alt. out ops.
Obviously, you could use a 2-10 to tap either battery for
e-bus support . . . but I think there is value in thinking
through the requirement for dual batteries . . .
Another solution may be to keep the main batt powering everything it
normally powers with alternator operating, and have the Aux batt for use
when the main batt voltage drops below a certain point. At that point
just select alternate feed of the essential bus to extend your time you
have to find a suitable field. Which sounds like a better way to go?
Your wife may wish that the airplane had 15# more payload
to bring home souvenirs of that trip to the Bahamas.
Perhaps if she dropped 15#s she could bring more souvenirs back, just
kidding honey.
Thanks Bob,
Jim. . .
==
==
==
==
________________________________________________________________________________
From: | Mickey Coggins <mick-matronics(at)rv8.ch> batteries |
Subject: | Essential bus alternate feed from two |
batteries
batteries
> Obviously, you could use a 2-10 to tap either battery for
> e-bus support . . . but I think there is value in thinking
> through the requirement for dual batteries . . .
Wow - this is interesting. I seem to have inferred from all
your previous posts and the book that for people with
electrically dependent engines (ignition/fuel pump) like
auto conversions that two batteries were a "must".
I guess this may be a case of choosing between "don't put
all your eggs in one basket" vs. "put all your eggs in
one basket - and watch that basket!"
Do I understand correctly that you would not consider
someone an idiot to fly an auto conversion with only
one alternator and one battery?
Thanks for sharing your wisdom!
Mickey
--
Mickey Coggins
http://www.rv8.ch/
#82007 QB Wings/Fuselage
________________________________________________________________________________
From: | "David Schaefer" <dschaefer1(at)kc.rr.com> |
Subject: | Garmin 430 install manual |
If you don't find it I can email you a copy.
David
RV6-A
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Jeffrey
W. Skiba
Subject: AeroElectric-List: Garmin 430 install manual
I seem to remember that there was somewhere to download the install manual
for garmin products in particular the 430? But I can not find it on there
site, Anybody know where I can download this ??
Thanks
Jeff.
________________________________________________________________________________
Subject: | Re: Dual fuel pumps |
From: | czechsix(at)juno.com |
Hi Bob,
Just an FYI for you or anyone else out there considering one of the "Bendix thump-thump"
pumps....I believe you're referring to the "beer can" cylindrical pumps
found on lots of Piper/other spam cans. These used to be Bendix but were
bought by Facet years ago, and Facet still produces them, but the newer models
now use solid-state triggering to control the solenoid for pumping action. This
replaces the points that the older ones used and should prove to be much more
reliable (not that they were bad to begin with)...Facet told me the design
life for the newer ones is over 5000 hours. If you want to make sure you're
getting one with solid-state triggering, you can tell by the "E" at the end of
the part number. I'm using the #40007E, which is identical to the pump you find
on your typical Piper Cherokee (#478360) except that 1) it has the solid state
triggering device instead of points and 2) it has 1/4" pipe thread for the
inlet/outlet fittings instead of 1/8" like the Pipe
rs use. If you need the 1/8" pipe thread fittings, and want the solid state triggering,
just get the #478360E model.
In case anyone wonders, the reason I used this type of pump on my RV-8A instead
of the little square one Vans recommends (I believe it's #40108) is because I
put it in the wing root, and the shape of the "beer can" pump and its inlet/outlet
locations seemed to fit better in the space available. I also like that
it has a 74 micron inlet filter screen that is pretty easy to remove and clean
periodically, whereas the square pump Vans uses does not have this feature.
FWIW, YMMV, etc. et al.
--Mark Navratil
Cedar Rapids, Iowa
RV-8A N2D firewall forward stuff...
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Dual fuel pumps
The Facet pumps, unlike their Bendix thump-thump ancestors
are all solid state for controlling solenoid current
and have very simple mechanical designs.
Bob . . .
________________________________________________________________________________
From: | Charlie Kuss <chaskuss(at)bellsouth.net> |
Subject: | Re: Electric fuel pump circuit |
Bob,
I'm sorry I was not clear. I have a mechanical pump as well.
Charlie
>
>>
>>Bob & Listers,
>> I am currently modifying your Z-11 drawing for my specific RV-8A. I
>> recall that you recently recommended the use of relays for circuits
>> drawing over 5 amps. My Airflow Performance electric fuel pump draws
>> about 5 - 6 amps in rush. Once running, it draws 3.5 to 4 amps. Do I need
>> a relay on this circuit? Would you recommend installing this circuit on
>> the main, endurance or battery bus? I have an engine with 1 magneto and 1
>> Jeff Rose electronic ignition.
>
> Does your fuel pump run all the time or is it a backup for
> an engine driven pump?
>
> Bob . . .
>
> -----------------------------------------
> ( Experience and common sense cannot be )
> ( replaced with policy and procedures. )
> ( R. L. Nuckolls III )
> -----------------------------------------
>
>
________________________________________________________________________________
From: | "GMC" <gmcnutt(at)uniserve.com> |
Subject: | Essential bus alternate feed from two batteries |
And of course there is always a simple solution like using toggle switches
for the ignition and letting the engine turn over two blades before turning
the ignition on! SOP for my 6-A.
George in Langley
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Jim
Stone
Subject: RE: AeroElectric-List: Essential bus alternate feed from two
batteries
Bob said:
???? Is it the stated policy/recommendation by the manufacturer
of the ignition system that you do this? I'm increasingly mystified
by what I perceive as an upsurge in worries about this. Perhaps
it's just that the economy is improving and more folks are building
airplanes with electronic ignition. Market forces notwithstanding,
I'm wondering if the risk is real and whether or not the
manufacturers
of these products are acknowledging a shortcoming in their product's
design. The low voltage event during cranking is tens of milliseconds
long as the starter motor spins up. There is no good reason why
you as the user should have to be concerned about this. Designing
sensitivity to this phenomenon out of the ignition system is
a rudimentary technique of circuit design.
Yes it is. I guess this somewhat "rare" problem is occurring due to the
high inrush current that some of the super light starter motors can
draw. Skytec sees the problem on a regular basis in the return of their
units for repair following a kickback. As I mention earlier, if the
conditions are right, i.e., its cold, battery a bit weak or old or both,
and you some how find yourself with less than minimum volts to power the
EI, you may have an expensive repair on your hands. A second battery is
just one way to avoid it.
Dual, rotated batteries implies two batteries of the same
size. My personal favorite is the 17 a.h. VSLA/RG battery
at 15 or so pounds. If you're willing to carry a 15# "penalty"
for the value of improved battery performance, perhaps this
no big deal. You'll have a wealth of capacity aboard that
would allow you to close both battery contactors should
you find that the main battery is over-taxed during alternator
out ops.
I have dual Odyssey 680s 17 ah at 15# each. Most Rockets are a bit nose
heavy so an extra 5# of battery (in the rear) above the designed wt and
balance figure should be a wash between loss of payload and lighter
nose. Since battery power is my only electrical backup and with the
kickback concern and the plan for annual replacement of a battery, it
just all added up to having two identical batteries. Plenty of juice
during alt. out ops.
Obviously, you could use a 2-10 to tap either battery for
e-bus support . . . but I think there is value in thinking
through the requirement for dual batteries . . .
Another solution may be to keep the main batt powering everything it
normally powers with alternator operating, and have the Aux batt for use
when the main batt voltage drops below a certain point. At that point
just select alternate feed of the essential bus to extend your time you
have to find a suitable field. Which sounds like a better way to go?
Your wife may wish that the airplane had 15# more payload
to bring home souvenirs of that trip to the Bahamas.
Perhaps if she dropped 15#s she could bring more souvenirs back, just
kidding honey.
Thanks Bob,
Jim. . .
==
==
==
==
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> batteries |
Subject: | Essential bus alternate feed from two |
batteries
batteries
> batteries
>
>
> > Obviously, you could use a 2-10 to tap either battery for
> > e-bus support . . . but I think there is value in thinking
> > through the requirement for dual batteries . . .
>
>
>Wow - this is interesting. I seem to have inferred from all
>your previous posts and the book that for people with
>electrically dependent engines (ignition/fuel pump) like
>auto conversions that two batteries were a "must".
He said he has one mag and one electronic ignition.
The fact that one ignition is supported by a well
maintained battery and works in concert with a
mechanically driven ignition system seems to provide
a high degree of risk mitigation for his engine which
is therefore, NOT electrically dependent.
His question was predicated on assumptions that
(1) there is value in having a second battery to
accommodate an ignition system that may not be designed
to live in the real world and (2) if there are two
batteries (of equal size due to adoption of the new-
main-battery-yearly rotation philosophy) that perhaps
there was value in being able to tap the second battery
for endurance-bus power during alternator-out operations.
I reasoned that his battery selection choices
now included a consideration of going to two smaller
(and more expensive/difficult to find) batteries
capable of cranking the engine whereupon he would
also consider the combined capacity of two batteries
for e-bus support. If he stayed with the cheap and popular
17 a.h. battery, then there was a pretty good weight
penalty to pay for the price of supporting a less-than-
alternator-out battery capacity would be huge . . . and
his question properly considered the wisdom/utility of
tapping this extra reserve for e-bus support.
>I guess this may be a case of choosing between "don't put
>all your eggs in one basket" vs. "put all your eggs in
>one basket - and watch that basket!"
>
>Do I understand correctly that you would not consider
>someone an idiot to fly an auto conversion with only
>one alternator and one battery?
I'm certainly not qualified to assess anyone's
mental competency based on the degree of risk
mitigation they choose to fly with. I've seen
William Wynne's Corvair engine conversion presentations
at fly-ins. He's flown this engine in several
configurations with a single alternator, single battery,
single Kettering (stock) ignition system for what
is most certainly an electrically dependent engine.
See http://www.flycorvair.com
But with a single ignition system (that delivers
a high degree of reliability and service life with
reasonable attention to installation and maintenance)
there seems to be little added value by having more
than one, well maintained battery to power it.
He offers compelling reasoning to support that
philosophy.
However, if anyone really wants dual ignition systems,
he'll show you where to drill and tap the heads and
how to strap on some more hardware. When a second
system is added, one has to assess the value in
adding a second battery too . . . and this hasn't
even touched on fuel delivery considerations.
Every component added to offset the deleterious
effects of failure of other components comes at
a price of increased weight, complexity (increases
chances of pilot/mechanic error), cost of ownership
and potential DECREASE in overall reliability due
to unforeseen failure modes. The original post in
this thread was considering the value and technique
for making the best of a picky ignition system
and taping all the resources it forced onto the
design . . . reliability wasn't a concern.
Some people think I'm an idiot for climbing into
a light aircraft with the intent to transport
myself to someplace else . . . but what do they know?
Bob . . .
________________________________________________________________________________
From: | "Lowell Fitt" <lcfitt(at)inreach.com> |
Subject: | Re: ANR headsets |
I use the headset from DRE. They seem to boost highs while the ANR feature
is on, but also seem to attenuate the high frequencies when turned off. But
consider that I wear hearing aids and they are programmable digital models.
One feature they have that I use routinely while flying is to turn them to
program 3 which turns off the microphones and turns on an inductance coil in
the hearing aid that then will receive the magnetic signal from the headset.
This feature was designed for telephone use, which I haven't yet learned to
master.
----- Original Message -----
From: "Ron Lee" <rlee468(at)comcast.net>
Subject: AeroElectric-List: ANR headsets
>
> A couple of us older guys without perfect hearing (high range) have had to
return ANR headsets because we couldn't hear well on them. The problem is
the audio is very bass and little treble, kind of like the person on the
other end is on a distant speaker phone. We hear ok on standard headsets
but wanted the ANR to preserve our hearing. The question is, is this normal
or have we each gotten bad brands?
>
>
________________________________________________________________________________
From: | "John Slade" <sladerj(at)bellsouth.net> |
Subject: | Essential bus alternate feed from two batteries |
> Wow - this is interesting. I seem to have inferred from all
> your previous posts and the book that for people with
> electrically dependent engines (ignition/fuel pump) like
> auto conversions that two batteries were a "must".
Yes, I've been finding this interesting too. Now I think of it, I'd like to
be able to power my ebus (EFI, Fuel pumps, Injectors, Coils) from either
battery. Is there a wiring diagram that covers this?
John Slade
Cozy IV
________________________________________________________________________________
From: | "Ron Raby" <ronr(at)advanceddesign.com> |
Subject: | Re: metalic paint |
thanks
Ron
----- Original Message -----
From: "Jeff Hildebrand" <jhildebrand(at)crownequip.com>
Subject: RE: AeroElectric-List: metalic paint
>
> When we planned our metallic paint job, we had the same worries. We
> talked to Lancair and they said it was no problem, they have seen many
> planes with metallic paint and it was no issue.
>
> Jeff Hildebrand
> Lancair ES
> http://lancair.northstartraffic.ca
>
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com
> [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ron
> Raby
> To: aeroelectric-list(at)matronics.com
> Subject: Re: AeroElectric-List: metalic paint
>
>
>
> Randy
>
> My antenna's are mounted on the inside shooting through the fiberglass.
> I am
> assuming on an RV6 that the antenna's are on the outside of the plane
> and
> paint.?
>
> Thanks
>
> Ron Raby
> ----- Original Message -----
> From: <F1Rocket(at)comcast.net>
> To:
> Subject: Re: AeroElectric-List: metalic paint
>
>
> >
> > My RV-6 has dark blue metallic on the bottom with a lighter blue
> metallic
> above on white. No problems at all with any of the antennas (all on the
> bottom).
> >
> > Randy
> > F1 Rocket
> > http://f1rocket.home.comcast.net/
>
> > >
> > >
> > > To everyone:
> > >
> > > I am planning a blue metalic finish on the bottom of my plane. I was
> > > wondering if this will have an effect on the antenna's I have
> mounted on
> the
> > > inside? transponder, Nav and I have a com antenna mounted on the
> side,
> where
> > > the #s are. The N #s are also the blue metalic finish.
> > >
> > > Thanks
> > >
> > > Ron Raby
> > >
> > > Lancair ES
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
>
>
> ==
> ==
> ==
> ==
>
>
________________________________________________________________________________
From: | "James E. Clark" <james(at)nextupventures.com> |
Subject: | Flap motor testing |
Comments below.
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com
> [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of
> Benford2(at)aol.com
> Sent: Tuesday, February 24, 2004 10:42 AM
> To: aeroelectric-list(at)matronics.com
>
> It will never blow another fuse... . Jus kiddin.. Your
Another **out of the box** thing to look at is if there is any wire anywhere
in the circuit that may be "exposed". If so, the "bounce" could have made it
move just enough to short whe power was applied. If this was the case it
would have nothing to do with your load and would probably always work on
the ground.
> extensive testing is
> what homebuilding is all about, If it worked every time, woman
> and children
> would be constructing these things. My best guess would be the
Ben I must assume you are kidding with the comment (looking for the
smileys), but just in case, there **ARE** women constructing these things
... and doing a mighty fine job of it.
I hear that there are some young people that some of *would* call childern
that are about building as well.
James
________________________________________________________________________________
From: | "Colt Seavers" <rv7maker(at)hotmail.com> |
Subject: | Garmin 430, where to purchase |
Listers,
Where is the best place to purchase a garmin 430? Local avionics shop,
internet shop, mail order? Are there any warrantee issues to contend with
if you install it yourself?
-Ross Schlotthauer
www.experimentalair.com
RV-7 finishing
>From: "David Schaefer" <dschaefer1(at)kc.rr.com>
>Reply-To: aeroelectric-list(at)matronics.com
>To:
>Subject: RE: AeroElectric-List: Garmin 430 install manual
>Date: Tue, 24 Feb 2004 18:17:37 -0600
>
>
>
>If you don't find it I can email you a copy.
>
>David
>RV6-A
>
>
>-----Original Message-----
>From: owner-aeroelectric-list-server(at)matronics.com
>[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Jeffrey
>W. Skiba
>To: aeroelectric-list(at)matronics.com
>Subject: AeroElectric-List: Garmin 430 install manual
>
>
>
>I seem to remember that there was somewhere to download the install manual
>for garmin products in particular the 430? But I can not find it on there
>site, Anybody know where I can download this ??
>
>Thanks
>Jeff.
>
>
________________________________________________________________________________
From: | richard(at)riley.net |
Subject: | Re: Garmin 430, where to purchase |
If you buy it from an avionics shop they are required by their dealership
agreement to install it in your airplane.
If you want to install it yourself, you have to buy it from a private
party. Then there's as much warrantee on it as there is warrantee left
since it was new - maybe a lot, maybe none.
>
>Listers,
>
>Where is the best place to purchase a garmin 430? Local avionics shop,
>internet shop, mail order? Are there any warrantee issues to contend with
>if you install it yourself?
>
>-Ross Schlotthauer
>www.experimentalair.com
>RV-7 finishing
>
>
> >From: "David Schaefer" <dschaefer1(at)kc.rr.com>
> >Reply-To: aeroelectric-list(at)matronics.com
> >To:
> >Subject: RE: AeroElectric-List: Garmin 430 install manual
> >Date: Tue, 24 Feb 2004 18:17:37 -0600
> >
> >
> >
> >If you don't find it I can email you a copy.
> >
> >David
> >RV6-A
> >
> >
> >-----Original Message-----
> >From: owner-aeroelectric-list-server(at)matronics.com
> >[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Jeffrey
> >W. Skiba
> >To: aeroelectric-list(at)matronics.com
> >Subject: AeroElectric-List: Garmin 430 install manual
> >
> >
> >
> >I seem to remember that there was somewhere to download the install manual
> >for garmin products in particular the 430? But I can not find it on there
> >site, Anybody know where I can download this ??
> >
> >Thanks
> >Jeff.
> >
> >
>
>
________________________________________________________________________________
From: | Mickey Coggins <mick-matronics(at)rv8.ch> batteries |
Subject: | Essential bus alternate feed from two |
batteries
batteries
> But with a single ignition system (that delivers
> a high degree of reliability and service life with
> reasonable attention to installation and maintenance)
> there seems to be little added value by having more
> than one, well maintained battery to power it.
Could I extend this reasoning to say that if I have
an aircraft with two electric fuel pumps, one
quality alternator, and one electronic ignition that
I too would have little or nothing to gain by
having a second battery?
I'm still "designing"/drawing my system, so
if it is one battery or two it won't make much
difference, but I am a firm believer in the KISS
principle. One well maintained battery sounds
simpler to me, but getting back on the ground
safely is my primary concern. This will be a VFR RV8.
Thanks,
Mickey
--
Mickey Coggins
http://www.rv8.ch/
#82007 QB Wings/Fuselage
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> batteries |
Subject: | Essential bus alternate feed from two |
batteries
batteries
> batteries
>
>
> > But with a single ignition system (that delivers
> > a high degree of reliability and service life with
> > reasonable attention to installation and maintenance)
> > there seems to be little added value by having more
> > than one, well maintained battery to power it.
>
>Could I extend this reasoning to say that if I have
>an aircraft with two electric fuel pumps, one
>quality alternator, and one electronic ignition that
>I too would have little or nothing to gain by
>having a second battery?
Sure . . . but forgive me for using such non-quantified
terms as "little" . . . at least "little" is not
zero. One could easily make an argument for risk
reduction by driving on the city streets only
between the hours of midnight and 5 a.m. . . .
but then your next accident might have a root
cause in your lack of sleep and nothing to do
with how many cars share the roadway with you.
It's a trade off between values added and
values lost and their inter-related effects.
>I'm still "designing"/drawing my system, so
>if it is one battery or two it won't make much
>difference, but I am a firm believer in the KISS
>principle. One well maintained battery sounds
>simpler to me, but getting back on the ground
>safely is my primary concern. This will be a VFR RV8.
Over the past 50 years, aviation has demonstrated
the relative risks for accident due to equipment
failure is very low . . . and MOST of those
events can be traced back to poor maintenance
(due to regulatory driven expenses) and not
taking advantage of the evolutionary improvements
in equipment technologies (again, a regulatory
driven condition). If you could outfit a stock
C-172 with an ND alternator, RG battery and an
e-bus, and make the maintenance of these items
as inexpensive for the C-172 as it is for an
RV-8, I'd guess that the dark-n-stormy night
stories on electrical system problems would
virtually disappear.
Anything we do beyond this simple change
with extra alternators, batteries, etc. etc.
are but icing on the cake . . . an increase
in levels of failure tolerance when failure
rates are already VERY low.
Since you're NOT having to deal with a C-172
and those-who-know-more-about-airplanes-than-
we-do, consider a single alternator, single
battery, e-bus design with electrically driven
engine accessories connected from the battery
bus. Leave room to add a second battery later
(go ahead and run the wire in for the aux
battery contactor control and leave room on
panel for extra switch).
See how things play for you with keeping a
fresh battery installed every annual (or
doing periodic battery tests to trigger
a replacement). Odds are very much in your
favor of never feeling a need for a second
battery . . . but if you want to, it's
a Saturday afternoon task.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> batteries |
Subject: | Essential bus alternate feed from two |
batteries
batteries
>
>And of course there is always a simple solution like using toggle switches
>for the ignition and letting the engine turn over two blades before turning
>the ignition on! SOP for my 6-A.
I was going to suggest that. The PM starter "disadvantage" is the
extra-ordinary magnitude of inrush current . . . an event that's
over in tens of milliseconds. Pushing the starter button before
turning on the ignition (and driving the ignition from the
battery bus) has a high order probability of eliminating the
problem and the need for a second battery.
Bob . . .
________________________________________________________________________________
From: | Richard Dudley <rhdudley(at)att.net> |
Subject: | Re: Garmin 430, where to purchase |
Ross,
Try John Stark of Stark Avionics
Hangar 12
Columbus Metro Airport
Columbus, GA 31909
706-321-1008
If he still has the same policies, his prices are the best at about 5%
over his cost. I'm surprised that no one else has mentioned him. Many
purchased from him in the past, myself included. They will also prewire.
Hope this helps.
Richard Dudley
-6A little details and pain prep
Colt Seavers wrote:
>
>
> Listers,
>
> Where is the best place to purchase a garmin 430? Local avionics shop,
> internet shop, mail order? Are there any warrantee issues to contend with
> if you install it yourself?
>
> -Ross Schlotthauer
> www.experimentalair.com
> RV-7 finishing
>
> >From: "David Schaefer" <dschaefer1(at)kc.rr.com>
> >Reply-To: aeroelectric-list(at)matronics.com
> >To:
> >Subject: RE: AeroElectric-List: Garmin 430 install manual
> >Date: Tue, 24 Feb 2004 18:17:37 -0600
> >
> >
> >
> >If you don't find it I can email you a copy.
> >
> >David
> >RV6-A
> >
> >
> >-----Original Message-----
> >From: owner-aeroelectric-list-server(at)matronics.com
> >[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Jeffrey
> >W. Skiba
> >To: aeroelectric-list(at)matronics.com
> >Subject: AeroElectric-List: Garmin 430 install manual
> >
> >
> >
> >I seem to remember that there was somewhere to download the install manual
> >for garmin products in particular the 430? But I can not find it on there
> >site, Anybody know where I can download this ??
> >
> >Thanks
> >Jeff.
> >
> >
>
________________________________________________________________________________
From: | "LarryRobertHelming" <lhelming(at)sigecom.net> |
Subject: | Re: Garmin 430, where to purchase |
This the best I could find.
John Stark
E-mail Address(es):
jts7(at)mindspring.com
John is registered/certified Garman dealer.
Indiana Larry, RV7 Tip-up TMX-O-360 ACS2002 Dynon CNS430 Digitrak
Firewall Forward
----- Original Message -----
From: "Colt Seavers" <rv7maker(at)hotmail.com>
Subject: AeroElectric-List: Garmin 430, where to purchase
>
> Listers,
>
> Where is the best place to purchase a garmin 430? Local avionics shop,
> internet shop, mail order? Are there any warrantee issues to contend with
> if you install it yourself?
>
> -Ross Schlotthauer
> www.experimentalair.com
> RV-7 finishing
>
>
> >From: "David Schaefer" <dschaefer1(at)kc.rr.com>
> >Reply-To: aeroelectric-list(at)matronics.com
> >To:
> >Subject: RE: AeroElectric-List: Garmin 430 install manual
> >Date: Tue, 24 Feb 2004 18:17:37 -0600
> >
> >
> >
> >If you don't find it I can email you a copy.
> >
> >David
> >RV6-A
> >
> >
> >-----Original Message-----
> >From: owner-aeroelectric-list-server(at)matronics.com
> >[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Jeffrey
> >W. Skiba
> >To: aeroelectric-list(at)matronics.com
> >Subject: AeroElectric-List: Garmin 430 install manual
> >
> >
> >
> >I seem to remember that there was somewhere to download the install
manual
> >for garmin products in particular the 430? But I can not find it on there
> >site, Anybody know where I can download this ??
> >
> >Thanks
> >Jeff.
> >
> >
>
>
________________________________________________________________________________
From: | Dave Morris <dave(at)davemorris.com> |
Subject: | Re: batteries and diode isolation |
Bob, I'd like to understand better why you prefer to use contactors and
separate buses for 2 batteries, as opposed to diodes and allowing both
batteries to feed the same bus.
I recently saw an elegant circuit that does this and allows both batteries
to be charged by the alternator at the same time.
I have read your treatise on battery isolation so many times I can almost
quote it, but nowhere do you address the possibility that there might be a
way of allowing 3 electrical sources to "automatically" determine - using
diodes - which ones will be feeding the loads. It would seem to require so
much less pilot workload than flipping switches to cut in and out
batteries, requires less current than supporting 2 battery contactors, and
would still elegantly support the concept of annual battery rotation, low
voltage notification, etc.
Diodes are available now with voltage drop of 0.3V and with max forward
currents of 240A, so the diodes themselves would not seem to be an issue.
What am I missing?
Thanks,
Dave Morris
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>Bob, I have not tried to measure the energy in the load dump event. When
>I started observing some component damage, I started to try to control
>it. This was with an alternator pulling about 35 to 40 amps.
>I tried the easy stuff first, and the 5KWatt TVS device was my second
>effort after the 1.5K.
>Regards, George
Understand. As soon as I can get the next revision of the 'Connection
to the printers, I'll be going up to B&C to run some factory stock
ND alternators in the battery-dump scenario and get some data. I'm
99% certain that some combination of TVS devices will provide the
needed protection but I can't size them without the numbers. I'm
also interested in seeing how well the stock alternator regulator
can stand off it's own transients.
>[PS... Bob, this is being sent as plaint text instead of HTML... should
>stop the gibberish from the last message.]
Yup, that works. The list-server won't pass html in a form
that folks e-mail application will understand. Plain text always works.
Bob . . .
________________________________________________________________________________
From: | "Shaun Simpkins" <shauns(at)hevanet.com> |
Subject: | Re: ANR Headsets |
Do you mean you can't hear radio transmissions well?
Lowell is correct - ANR headsets should have exactly the opposite effect
of what you describe. Any sound that makes it into the earcup will have
its bass cut ( the ANR intended effect ). The earcup will provide increasing
attenuation with increasing frequency.
An unavoidable consequence of the ANR mechanism is that wind noise
frequencies - about 1000Hz, a relatively high pitch - are somewhat
boosted. The overall attenuation curve will show progressively increasing
attenuation, with a flattening between 500-2000Hz.
ANR headsets that weren't designed for good "music" reproduction will
have a very limited high frequency range. If the frequencies between 3K
and 8K are compromised you will get very poor speech discrimination.
Most ANR headsets fall into this category. You might
want to try a better quality headset, perhaps one with a music input. This
usually means that the speakers have been selected with a broad frequency
response in mind.
I have had good results with any Lightspeed product. The 20 3G and 30 3G
might be particularly applicable to your situation, since they have "bass boost"
and "treble boost" controls that are intended to partially compensate for
high-frequency hearing loss. But there are others. In general, up to about
$600/set, you get what you pay for.
Note also that any ANR headset I know of will not be that great at "realistic"
music
reproduction because it can't distinguish between externally-generated signals
and line-introduced signals. Like I said, anything that makes it inside the
earcup is affected by the ANR, and low frequencies are affected the most.
SS
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> bat teries |
Subject: | Essential bus alternate feed from two |
bat teries
bat teries
>
>
> batteries
>
>
> >During start I thought I would use the main battery for cranking engine,
> >the aux battery for powering the electronic ignition (to avoid any
> >possibility of kick back in the event main battery voltage drops below
> >min required for electronic ignition).
>
> ???? Is it the stated policy/recommendation by the manufacturer
> of the ignition system that you do this? I'm increasingly mystified
> by what I perceive as an upsurge in worries about this. Perhaps
> it's just that the economy is improving and more folks are building
> airplanes with electronic ignition. Market forces notwithstanding,
> I'm wondering if the risk is real and whether or not the manufacturers
> of these products are acknowledging a shortcoming in their product's
> design. The low voltage event during cranking is tens of milliseconds
> long as the starter motor spins up. There is no good reason why
> you as the user should have to be concerned about this. Designing
> sensitivity to this phenomenon out of the ignition system is
> a rudimentary technique of circuit design.
>
>Bob,
>
>This may be a legitimate "worry". I spent quite a bit of time and energy
>attempting to resolve the starting problems with my LSE ignition system. I
>have a permanent magnet Lycoming starter, a 17 AH battery, and I start the
>engine on the electronic ignition only. My engine would only start when I
>released the starter button. It always started, but it left me with an
>uneasy feeling that sometime, far away from home, it may not. The voltage
>(measured at the ignition module) drops to around 8 volts with the starter
>engaged, and the LSE does not fire at that voltage, regardless of what
>Klause claims. I resolved the problem for now by switching to an Odyssey
>battery, which does not produce quite as much voltage drop. A better
>solution is a B & C starter that draws less current, but that cost $$$. If
>I were building an airplane with two batteries, I would certainly consider
>starting on one and powering the electronic ignition from the other.
Hmmm. Did you try leaving the ignition switch off until after
the engine was rotating?
Bob . . .
________________________________________________________________________________
From: | "James E. Clark" <james(at)nextupventures.com> |
Subject: | Z-14/RV6,7,9/PC680 (Dual-Dual) ?????? |
This is more mechanical than electrical but relates to the positioning of
"electrical stuff". ....
I am curious if anyone has implememted Z-14 using dual PC-680's on the
firewall of an RV6A, 7A, or 9A.
- If you have, where did you mount the two batteries?
- Did you use Van's kit?
- Was there a problem with the wiring of the contactors in Van's proposed
location for the PC680 (their design is for one battery)?
- Did you mount the contactors elsewhere?
As I see it there are two potential locations for the batteries:
1. As proposed by Van's .. near the center recess, one on each side and
2. Lower left/right corner just high enough to clear the engine mount.
Both have their potential problems regarding routing of wires and/or removal
of the battery.
The other question is whether anyone who has done this had any weight and
balance issues. I don't think there are but just checking for actual
implementations.
Thanks,
James
________________________________________________________________________________
Subject: | Re: Flap motor overload? |
Boeing uses the minimum flight crew required by the airplane.
BB
----------------------------------------------
Original Message
From: ""<Benford2(at)aol.com>
Subject: Re: AeroElectric-List: Flap motor overload?
Date: Mon, 23 Feb 2004 21:47:35 EST
>
>In a message dated 2/23/2004 9:18:07 AM Mountain Standard Time,
>cgalley(at)qcbc.org writes:
>
>
>>
>> Having a second person in the cockpit is strictly prohibited by FARs for
our
>> amateur Built planes. Could generate a lot of problems both with the FAA
and
>> the insurance company.
>>
>> Cy Galley
>> Editor, EAA Safety Programs
>> cgalley(at)qcbc.org or sportpilot(at)eaa.org
>>
>>
>
>Some of these homebuilts get kinda complex and a second person would be a
>safety factor. Tell me, What does Boeing do on their first flights of new
and
>unproven designs??? Is there just one pilot??? After all they all start
life as a
>homebuilt...
>
>Ben Haas N801BH.
>
>
http://www.MyOwnEmail.com
________________________________________________________________________________
From: | Mark Steitle <msteitle(at)mail.utexas.edu> bat teries |
Subject: | Essential bus alternate feed from two |
bat teries
bat teries
>...My engine would only start when I
> >released the starter button.
I have noticed this interesting condition when starting my 1995 GL-1500
Honda Goldwing motorcycle after it has sat in storage for a few weeks. If
I would charge the battery first, then this wouldn't happen. Sounds like
exactly the same thing to me. Condition has pretty much resolved upon
installing a new RG battery. Need to ride more often!
Mark S.
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> combined output |
Subject: | Re: Two alternators-using total rated |
combined output
combined output
>
>
>Bob, going way back to last August - you suggested it was "not simple" and
>"probably not cost effective" to install, for example, 2ea 20 amp
>alternators and plan on loading them up for near 40 amps steady load - that
>"balancing" and not "causing 1 to produce output over its rated value" was a
>big deal. (I'm paraphrasing & summarizing from the e-mail which is quoted
>below this.)
>
>I was just thinking today of installing two John Deere PM 20 amp
>alternators, using 2 different belts, so as to have a more fault tolerant
>system requiring 32 to 35 amp steady load, total. I have roughly analyzed
>my night/IFR system to be running about 32 amps, steady, under heaviest
>loads.
>
>Without asking you to design the system for me - I respect the work load you
>already have - could you give a quick tutorial to guide me thru the design
>and test of such a system? (or persuade me it's too hard to do with my lack
>of knowledge and test equip)?
it's relatively easy to make two wound field alternators
share a load. You build a "slaving" module that modifies
the bus sense lead for one regulator such that the other
regulator becomes the "master". You use a pair of shunts,
one in each alternator output lead to tell the slaving
module which what to steer the slave regulator so that
the currents are equal.
>Sounds like 1) the "magic" has to be in the "voltage regulator(s)", not just
>how the system is wired up; and 2) the most serious problem is 1 "20 amp
>RATED alternator" actually having the ability to put out much more, but at
>the expense of running over its "rating" and thus overheating and suffering
>a "stress" it was not designed for - probably the same for the REGULATOR
>that is also rated for 20 amps.
>
> - What is the "simplest" way to a) have the two identical regulators
>and alternators each share roughly 1/2 of the load, whatever it is, or, b)
>allow 1 alternator to go up to its rated output and then have any subsequent
>increase in load be picked up by the other alternator? Are there other
>"approaches" to this?
You'd have to build your own regulators to provide a low
current, bus voltage sense input that can be steered from
the outside. If you've got room for a 20A PM alternator,
isn't there enough room for a 40A ND alternator?
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Dual fuel pumps |
>
>
>Hi Bob,
>
>Just an FYI for you or anyone else out there considering one of the
>"Bendix thump-thump" pumps....I believe you're referring to the "beer can"
>cylindrical pumps found on lots of Piper/other spam cans. These used to
>be Bendix but were bought by Facet years ago, and Facet still produces
>them, but the newer models now use solid-state triggering to control the
>solenoid for pumping action.
Good data Mark. Thanks!
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Electric fuel pump circuit |
>
>Bob,
> I'm sorry I was not clear. I have a mechanical pump as well.
>Charlie
Okay, so there's little risk in wiring it for 7A (20AWG wire)
and running a 5A fuse during flyoff. Do some extensive testing
during flyoff to see that the 5A fuse is adequate . . . raise
to 7A if needs be but it seems unlikely. Whether or not you
add the relay is problematic . . . I think there's more risk
that the pump is NOT available because of failure in higher
circuit complexity than the risk of fire for hitting the
mountainside with an always hot battery bus feeder fused at 7A.
But as we've discussed here before, it'a a matter of taste
and subscription to long held and deeply rooted beliefs.
Start with 5A and lets revisit this discussion if it testing
shows that you can open the 5A fuse with repeated pump
actuations.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Flap motor testing |
>
>
>Possible heat build up in fuse from first two T&G's. Is the fuse
>cartridge a SLO-BLOW or a standard link type?
The ATC plastic fuse only comes in a medium speed link.
I'm mystified as to why this issue has jumped up on Mark's
airplane. There are LOTS of RV's flying with fused flap motor
circuits. Is there anyone flying that found it necessary to
fuse an RV flap motor at more than 10A?
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: William Wynne's Corvair Conversions |
>
>
> > I'm certainly not qualified to assess anyone's
> > mental competency based on the degree of risk
> > mitigation they choose to fly with. I've seen
> > William Wynne's Corvair engine conversion presentations
> > at fly-ins. He's flown this engine in several
> > configurations with a single alternator, single battery,
> > single Kettering (stock) ignition system for what
> > is most certainly an electrically dependent engine.
> >
> > See http://www.flycorvair.com
> >
> > But with a single ignition system (that delivers
> > a high degree of reliability and service life with
> > reasonable attention to installation and maintenance)
> > there seems to be little added value by having more
> > than one, well maintained battery to power it.
> > He offers compelling reasoning to support that
> > philosophy.
> >
>I just went to William Wynne's Corvair College about a month ago. Risk
>management is a large part of his philosophy. He now advocates an ignition
>system with dual points going to dual coils with a coil switcher. (All are
>high quality parts, and the coils and coil switcher are kept cool and away
>from the engine).
I wonder if he indicated that he'd ever had a failure . . . or was this
simply belt-n-suspenders approach to a market steeped in the
value of redundant everything.
> He also does not advocate flying a Corvair under IFR
>conditions. For that, he says, go with a certified engine.
It would be interesting to know if his concerns have
any foundations with mechanical issues for the basic
engine . . . or whether they're limited to issues of
fuel delivery and ignition systems. I hope he shows up
at the Tandem Wing fly-in this year. I'd like to talk
with him again.
> The failure
>mode of the points is that they gradually lose their effectiveness, giving
>fair warning with hard starting.
>
>Ironically, there are people who don't like having a system with points, but
>prefer mags. As I understand it, mags have points.
Exactly. I used to replace points in my Kettering ignition cars
every fall along with other components as part of a just-before-
winter-tune-up. Car started great all winter and nothing was
badly worn by the next fall. Total cost of ignition and carburetor
refurbishment kit was about $25 and took a Saturday afternoon
to install. Cheap, easy and effective.
12,000 miles at average of 30 mph was 400 hours per year
on the points and plugs and they looked pretty good each
fall at replacement time. 400 hours on the average airplane
takes 8 years. Some engines on the C-195 were fitted with
one mag and one Kettering system. A friend of mine owned
one and had much more problems with the mag than he did
with the Kettering points-and-coil system.
>Because he is using a Corvair engine in a direct drive configuration and low
>rpm, he says the points will last a long time. (He is specific that only
>standard points that have a phenolic - not plastic- rubbing block are to be
>used. The springs on the competition points are too stiff and unnecessary
>at a max of around 3300 rpm). One person flying a Corvair (with a single
>point system), changed the points at the 25 hour mark, and noticed that
>there was no wear. Since then, he's got something like 800 hours on the
>same set of points. He performs regular maintenance on them, and has been
>inspecting and dressing, and re-gapping them as necessary. William is not
>advocating that, just illustrating how long-lived points can be with proper
>care.
Yup!
>William claims that since he's never seen lead fouling of the plugs on a
>Corvair airplane powerplant, he now uses a single plug per cylinder. (The
>engine was designed when high lead, high octane gasoline were common).
>
>The thing that impresses me about William is that if he advocates something,
>he's either flown it, run it on a test stand, or closely monitored someone
>else's use of it. For example, he has found by experimentation that the
>9.25:1 heads are actually less prone to detonation than the 8.25:1 heads.
>The reason? The quench area of the 9.25:1 heads is much larger, and
>produces much more swirling of the mixture during compression.
I was similarly impressed with his presentations. He's
a good scientist as well as able practitioner. A valuable
resource for the OBAM aircraft community.
Bob . . .
________________________________________________________________________________
From: | Jerry2DT(at)aol.com |
Subject: | Re: Flap motor testing |
For what it's worth... I noted before we suffered two flap motor failures in
40 hrs on our RV6a, both were caused by "crap" between the brushes and
commutator. We never blew a fuse, but might it be possible that you could be having
the same thing happen and causing a blown fuse. I'm not electrically educated,
but seems possible. This particular problem has happened many times with other
RV's. Others think this gunk is grease coming from flap gearbox, but it would
have had to come through the motor housing and no evidence at all there. I
think it might be residue from the copper brushes. If it happens again I will
take pains to analyse it. The mystery continues...
Bob... thanks for all you do, you are a godsend.
Jerry Cochran
In a message dated 2/24/2004 11:57:21 PM Pacific Standard Time,
aeroelectric-list-digest(at)matronics.com writes:
From: Fiveonepw(at)aol.com
Subject: AeroElectric-List: Flap motor testing
Thanks to all for your thoughts on the flap fuse failure fiasco- lot's of
good info... The following is long, tedious and boring (unless you're an
electrical masochist!) so delete now if so inclined............
________________________________________________________________________________
From: | "Dan Branstrom" <danbranstrom(at)verizon.net> |
Subject: | Re: William Wynne's Corvair Conversions |
>I just went to William Wynne's Corvair College about a month ago. Risk
>management is a large part of his philosophy. He now advocates an ignition
>system with dual points going to dual coils with a coil switcher. (All are
>high quality parts, and the coils and coil switcher are kept cool and away
>from the engine).
I wonder if he indicated that he'd ever had a failure . . . or was this
simply belt-n-suspenders approach to a market steeped in the
value of redundant everything.
I believe it is a matter of looking at which items and under what conditions
they are most prone to failure. I don't think he's ever had a failure on
his craft, but he considers the coil and an individual set of points as the
parts you'd never want to fail. It's probably belt-and-suspenders.
________________________________________________________________________________
From: | Charlie Kuss <chaskuss(at)bellsouth.net> |
Subject: | Re: Electric fuel pump circuit |
Bob,
I was hoping you'd say that. (forget the relay) Do I understand you correctly?
You feel the pump should be wired to the battery bus?
Charlie
>
>>
>>Bob,
>> I'm sorry I was not clear. I have a mechanical pump as well.
>>Charlie
>
> Okay, so there's little risk in wiring it for 7A (20AWG wire)
> and running a 5A fuse during flyoff. Do some extensive testing
> during flyoff to see that the 5A fuse is adequate . . . raise
> to 7A if needs be but it seems unlikely. Whether or not you
> add the relay is problematic . . . I think there's more risk
> that the pump is NOT available because of failure in higher
> circuit complexity than the risk of fire for hitting the
> mountainside with an always hot battery bus feeder fused at 7A.
> But as we've discussed here before, it'a a matter of taste
> and subscription to long held and deeply rooted beliefs.
>
> Start with 5A and lets revisit this discussion if it testing
> shows that you can open the 5A fuse with repeated pump
> actuations.
>
> Bob . . .
>
>
________________________________________________________________________________
From: | PeterHunt1(at)aol.com |
Subject: | Garmin 430, where to purchase |
Colt, I shopped around for my Garmin 530 and found the best deal to be from
John Stark, Stark Avionics, Columbus, Georgia (706) 321-1008. He'll even make
up connecting cables for you.
Pete Hunt
Clearwater, Florida
RV-6, installing engine
________________________________________________________________________________
From: | "David Schaefer" <dschaefer1(at)kc.rr.com> |
Subject: | Garmin 430, where to purchase |
As far as I'm concerned the best pricing on any avionics is from Bill Pippen
at 830-997-8205. I priced Stark and found him higher so I bought my 430s
from Bill. Bill is an RV6 driver and a great guy.
David Schaefer
RV6-A Finish Kit
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Colt
Seavers
Subject: AeroElectric-List: Garmin 430, where to purchase
Listers,
Where is the best place to purchase a garmin 430? Local avionics shop,
internet shop, mail order? Are there any warrantee issues to contend with
if you install it yourself?
-Ross Schlotthauer
www.experimentalair.com
RV-7 finishing
>From: "David Schaefer" <dschaefer1(at)kc.rr.com>
>Reply-To: aeroelectric-list(at)matronics.com
>To:
>Subject: RE: AeroElectric-List: Garmin 430 install manual
>Date: Tue, 24 Feb 2004 18:17:37 -0600
>
>
>
>If you don't find it I can email you a copy.
>
>David
>RV6-A
>
>
>-----Original Message-----
>From: owner-aeroelectric-list-server(at)matronics.com
>[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Jeffrey
>W. Skiba
>To: aeroelectric-list(at)matronics.com
>Subject: AeroElectric-List: Garmin 430 install manual
>
>
>
>I seem to remember that there was somewhere to download the install manual
>for garmin products in particular the 430? But I can not find it on there
>site, Anybody know where I can download this ??
>
>Thanks
>Jeff.
>
>
________________________________________________________________________________
From: | Chad Robinson <crobinson(at)rfgonline.com> |
Subject: | Re: Essential bus alternate feed from two batteries |
John Slade wrote:
>
>>Wow - this is interesting. I seem to have inferred from all
>>your previous posts and the book that for people with
>>electrically dependent engines (ignition/fuel pump) like
>>auto conversions that two batteries were a "must".
>
> Yes, I've been finding this interesting too. Now I think of it, I'd like to
> be able to power my ebus (EFI, Fuel pumps, Injectors, Coils) from either
> battery. Is there a wiring diagram that covers this?
> John Slade
> Cozy IV
John, you can just use whatever diagram you prefer (Z-14 maybe?) and add a
second switch (or replace the SPST switch with a SPDT switch). The current
e-bus feed works via a wire from the battery bus to a switch to the e-bus. If
you lose your alternator, you can shut off the main contactor, eliminating its
load, and flip the switch, and the e-bus is hooked right to the battery.
So all you have to do is add a wire from the OTHER battery bus to a second
switch to the e-bus. You can technically do this with one switch but I prefer
two because it gives you more options - normal, e-bus on primary, e-bus on
secondary, e-bus on both (both switches on). You would need a 4-pole switch to
get the same functionality in a single control and they're both rare and
clumsy to use. Running on both means you can extend your range if your
alternator fails. Running on either/or lets you isolate a bad battery.
If you can hook your voltmeter up to your e-bus it makes isolating a bad
battery even easier - just flip the switches to alternate positions and see
which gives you a higher voltage (assuming the alternator is offline). This is
especially useful on the ground because you can directly check the voltage of
each battery separately - although this is really too simplistic to identify a
"good" battery, at least it will show you the charge level.
I can send a schematic, but it's really simple - just add a fuse, wire, and
switch per the existing diagrams but hook the second set up to the alternate
battery bus. There's no need for diodes because you control the supply
yourself via the switches.
Regards,
Chad
________________________________________________________________________________
From: | Fiveonepw(at)aol.com |
Subject: | Re: Flap motor testing |
In a message dated 02/25/2004 3:18:46 PM Central Standard Time,
bob.nuckolls(at)cox.net writes:
I'm mystified as to why this issue has jumped up on Mark's
airplane. There are LOTS of RV's flying with fused flap motor
circuits. Is there anyone flying that found it necessary to
fuse an RV flap motor at more than 10A?
Flew again today with an LED front & center on the panel tied directly to the
fuse output- did many landings and, several "not so pretty" combined with a
fair amount of "flap abuse", and the damn fuse never blew- go figure...
I'm gonna keep the "idiot light" connected for a while and see what goes
down- if I learn anything, I'll letcha know!
Mark
________________________________________________________________________________
Subject: | Antenna Questions |
From: | Don Boardman <dboardm3(at)twcny.rr.com> |
Hi All,
As mentioned on the list earlier, we are installing a Loran as a second nav
to our KMD 150 GPS. A friend had an antenna that he gave us. It is a
physical match to the Com Antennas found on most Cessnas. It indicates it is
a Loran antenna on the bottom.
Do I need to use the pre-amp that came with the Loran with this type
antenna?
I can always experiment and look at the results with and without the
pre-amp. Will it hurt to use the pre-amp if in fact it is not essential to
use?
My friend also brought with him an identical looking antenna with graphics
on its base that say: STS avionics. The identification tag on the bottom is
mostly gone. Does anyone know if this is a Com antenna or another Loran
antenna? The friend did not know.
Is there a way to tell which type it is?
Is there a way other than hooking an antenna to a unit to tell if it is good
to go.
A last question. At one time I was told that is was not good to have a
transmitter powered up without a functioning antenna attached. That
transmitting with no antenna could damage the transceiver. Is this true?
Panel all pre-wired was clecoed into the airframe tonight!!!!!,
Don B
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Antenna Questions |
>
>Hi All,
>
>As mentioned on the list earlier, we are installing a Loran as a second nav
>to our KMD 150 GPS. A friend had an antenna that he gave us. It is a
>physical match to the Com Antennas found on most Cessnas. It indicates it is
>a Loran antenna on the bottom.
>
>Do I need to use the pre-amp that came with the Loran with this type
>antenna?
probably for best performance
>I can always experiment and look at the results with and without the
>pre-amp. Will it hurt to use the pre-amp if in fact it is not essential to
>use?
you can't hurt anything by leaving it off. if you're satisfied
with performance without it, then it's your choice.
>My friend also brought with him an identical looking antenna with graphics
>on its base that say: STS avionics. The identification tag on the bottom is
>mostly gone. Does anyone know if this is a Com antenna or another Loran
>antenna? The friend did not know.
>
>Is there a way to tell which type it is?
>
>Is there a way other than hooking an antenna to a unit to tell if it is good
>to go.
that's the best. mount it on a piece of aluminum, put an
antenna analyzer on it or transmitter and swr bridge and
see what it looks like.
>A last question. At one time I was told that is was not good to have a
>transmitter powered up without a functioning antenna attached. That
>transmitting with no antenna could damage the transceiver. Is this true?
When solid state transmitters first started showing up in
airplanes, they were particularly intolerant of high
standing wave ratio at the antenna terminal. There was
a standard caution about operating the transmitter into
an open coax . . . nowadays, any transmitter worth the
money has modern, more robust transistors in the output
stage and some designs include built in swr detection
schemes that automatically throttle back an at-risk
output stage so that high swr won't damage it.
You'd have to look at the schematic for your particular
radio to deduced whether or not this feature is in place.
What does your installation manual say about the
radio?
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Electric fuel pump circuit |
>
>Bob,
> I was hoping you'd say that. (forget the relay) Do I understand you
> correctly? You feel the pump should be wired to the battery bus?
>Charlie
I think I would. There's some compelling thought for being
able to make the panel completely dark without affecting
anything needed to keep the engine running.
Bob . . .
________________________________________________________________________________
From: | Kenneth Melvin <melvinke(at)direcway.com> |
Subject: | Flap motor testing |
I run a Cessna flap motor with 10A fuse in my RV4, and have bent the
actuating rods without ever blowing a fuse!
Ken Melvin
N36KM
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Fiveonepw(at)aol.com
Subject: Re: AeroElectric-List: Flap motor testing
In a message dated 02/25/2004 3:18:46 PM Central Standard Time,
bob.nuckolls(at)cox.net writes:
I'm mystified as to why this issue has jumped up on Mark's
airplane. There are LOTS of RV's flying with fused flap motor
circuits. Is there anyone flying that found it necessary to
fuse an RV flap motor at more than 10A?
Flew again today with an LED front & center on the panel tied directly
to the
fuse output- did many landings and, several "not so pretty" combined
with a
fair amount of "flap abuse", and the damn fuse never blew- go figure...
I'm gonna keep the "idiot light" connected for a while and see what goes
down- if I learn anything, I'll letcha know!
Mark
==
==
==
==
________________________________________________________________________________
From: | "'Scott Richardson'" <scott_m_richardson(at)sbcglobal.net> |
Subject: | Inverting a signal condition |
Hi all,
I've constructed an annunciator panel along the lines of the one that
Mark Phillips described on this list back in December, but had a
question for some of the electronic circuit guys on the list. Most of
my signal conditions are such that when I want the indicator to light
(boost pump on, fuel low, etc.), the signal line goes high (bus voltage,
13.8v). However I have a couple of signals where the signal is
indicated by the signal line going to ground (the Low Volt light on the
B&C regulator for example). I'm looking for some mechanism to
effectively switch this type of low indication to high. I'd need
something that would:
a) drive the output voltage at the normal electrical bus voltage (since
I'm using a zener diode for dimming, I need all LED driver voltages the
same)
b) be able to drive upwards of 40ma to drive my LED indicator
Because of (a), I can't simply use a inverter IC circuit - at least I
can't find one that drives at that type of output voltage AND can take
it's supply at bus voltage. My first response is to use a simple relay
like Digi-key part PB371-ND (12V, 3A, SPST:NO, PCB mount, about $1.50)
and make up a little PCB to hold a couple of them and a connector.
I don't see anything wrong with this method, just wondering if anyone
had any other suggestions. Thanks as always...
Scott
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Scott M Richardson scott_m_richardson(at)sbcglobal.net
________________________________________________________________________________
From: | Dave Morris <dave(at)davemorris.com> |
Subject: | Re: Inverting a signal condition |
Install those LEDs backwards and wire the other lead to 12VDC.
Dave Morris
>
>
>Hi all,
>
>I've constructed an annunciator panel along the lines of the one that
>Mark Phillips described on this list back in December, but had a
>question for some of the electronic circuit guys on the list. Most of
>my signal conditions are such that when I want the indicator to light
>(boost pump on, fuel low, etc.), the signal line goes high (bus voltage,
>13.8v). However I have a couple of signals where the signal is
>indicated by the signal line going to ground (the Low Volt light on the
>B&C regulator for example). I'm looking for some mechanism to
>effectively switch this type of low indication to high. I'd need
>something that would:
>
>a) drive the output voltage at the normal electrical bus voltage (since
>I'm using a zener diode for dimming, I need all LED driver voltages the
>same)
>b) be able to drive upwards of 40ma to drive my LED indicator
>
>Because of (a), I can't simply use a inverter IC circuit - at least I
>can't find one that drives at that type of output voltage AND can take
>it's supply at bus voltage. My first response is to use a simple relay
>like Digi-key part PB371-ND (12V, 3A, SPST:NO, PCB mount, about $1.50)
>and make up a little PCB to hold a couple of them and a connector.
>
>I don't see anything wrong with this method, just wondering if anyone
>had any other suggestions. Thanks as always...
>
>Scott
>*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
>Scott M Richardson scott_m_richardson(at)sbcglobal.net
>
>
________________________________________________________________________________
From: | Chad Robinson <crobinson(at)rfgonline.com> |
Subject: | Re: Inverting a signal condition |
'Scott Richardson' wrote:
>
> Hi all,
>
> I've constructed an annunciator panel along the lines of the one that
> Mark Phillips described on this list back in December, but had a
> question for some of the electronic circuit guys on the list. Most of
> my signal conditions are such that when I want the indicator to light
> (boost pump on, fuel low, etc.), the signal line goes high (bus voltage,
> 13.8v). However I have a couple of signals where the signal is
> indicated by the signal line going to ground (the Low Volt light on the
> B&C regulator for example). I'm looking for some mechanism to
> effectively switch this type of low indication to high. I'd need
> something that would:
>
> a) drive the output voltage at the normal electrical bus voltage (since
> I'm using a zener diode for dimming, I need all LED driver voltages the
> same)
> b) be able to drive upwards of 40ma to drive my LED indicator
>
> Because of (a), I can't simply use a inverter IC circuit - at least I
> can't find one that drives at that type of output voltage AND can take
> it's supply at bus voltage. My first response is to use a simple relay
> like Digi-key part PB371-ND (12V, 3A, SPST:NO, PCB mount, about $1.50)
> and make up a little PCB to hold a couple of them and a connector.
>
> I don't see anything wrong with this method, just wondering if anyone
> had any other suggestions. Thanks as always...
There are dozens of ways to do this. Your way with relays works fine, although
it's a mechanical part that you might want to eliminate. It also requires
enough power to hold the relay closed, although generally not much. Or you
could just use a transistor and two resistors. My schematic capture app is
down right now (reloading my system), but in rough ASCII art it would be:
1k
+12V supply ----\/\/\--------Collector of T1, and output
1k
Input signal ---\/\/\---Base of T1
Ground ----------------------Emitter of T1
where T1 is a 2N2222 or similar NPN transistor. The 2N2222 can sink about
800mA of current if it's heatsinked in this case. You can use a larger NPN
transistor, like the ZTX1053A (handles up to 3A) if necessary, but your 40mA
requirement is way lower than this even if you drive multiple indicators.
This is a pretty simple circuit. While the input is 0 (off) the transistor is
also off, so the output "sees" 12V through the 1K pull-up resistor. In fact,
if you're directly driving an LED you won't need a current limiter on it. You
can just adjust the value in this circuit.
If the input becomes 1, the transistor turns on, and the output "sees" a more
direct path to ground through it (output is thus ground, or 0). The resistor
on the base of the transistor is a current limiter for the device itself.
Regards,
Chad
________________________________________________________________________________
Hello Listers,
Who have information about a good source (hopefully inexpensive) for ND
alternator ?
I am looking to use a 50 amp. one on an O-320.
Thanks,
David
________________________________________________________________________________
From: | "flyv35b" <flyv35b(at)ashcreekwireless.com> |
Subject: | Emergency Buss/Standby Alternator |
Bob,
I have a 71 V35B Bonanza which I am in process of modifying the instrument
panel and the electrical system to improve it's IFR capability and
incorporate some backup systems. The original main bus (copper strip) was
cut and a separate avionics bus is now supplied through a 35amp breaker
switch via a 10 gauge wire. I have added an electric attitude indicator as
a backup for a vacuum failure and am planning on installing the B&C 20amp
standby alternator system. Even though this is not an OBAM aircraft, as an
A&P/IA I do all the modifications and maintenance. I would welcome your
opinion about some questions I have and others might be interested as well.
I would like to install an emergency buss with an always-hot feed off the
battery bus as a backup and to eliminate the single-point-of-failure
avionics switch. The EB would have numerous items, including an S-Tec 50
AP, (removed from the existing avionics and main bus) with a total MAX
current of nearly 20amp. Typical current would be more like 12amp, or less
if load was shed. The EB would be supplied with a 12ga wire/16ga fusible
link through a 20amp (or maybe 15a) breaker switch and normally through the
D-25 essential bus diode from the main or avionics bus automatically. I
would like the breaker switch to open before the fusible link fails so that
load could be shed and then the switch could be closed again.
1. Is the idea of having an EB even worthwhile if I incorporate the B&C
standby alternator system?
2. If it is, or if I don't incorporate the B&C alternator, does the D-25
essential bus diode have the capacity to handle the proposed current in the
normal direction? I assume this is the easiest way to supply the EB and the
0.6v drop is of no concern?
3. How would the D-25 fail if it did? Open circuit or what?
4. Is there a better way to protect the always-hot feed line such as with a
20amp current limiter (I haven't seen any with that low of rating)?
5. If I don't incorporate the EB should I install another breaker-switch in
parallel with the existing avionics master switch to eliminate the
single-point-of-failure?
Although the B&C system is STC'd for the Bonanza, would the addition of an
emergency buss constitute a major alteration in your opinion (changes to the
basic design of the electrical system - per FAR Part 43, Appendix A)?
List of items planned for the Emergency Buss
SL-30 Nav/Com 2.4a typ. 3.7a max.
GX-50 GPS 0.5a typ. 0.75a
max.
Electric AI 2.4a start
0.9a run
NSD-360 HSI 0.5a
KT-76C transponder 1.6a max.
Electronics Int'l VA-1A (volt/amp) 0.2a
EI OPT-1 (oil press/temp) 0.1a
EI FP-5L (fuel flow/qty) 0.1a
Horizon digital tach 0.2a
S-TEC 50 AP 1.0 ave. 5.0a max.
S-TEC turn coordinator 3.0a
MX-20 (optional) 2.0a typ. 3.0a
max.
Panel light LED
(negligible)
As always, I appreciate your expertise and vast knowledge and especially the
time you take to share it with others here on the web and in the Aero
Electric Connection.
Cliff Hanson A&P/IA
-- Original Message -----
From: "Robert L. Nuckolls, III bat teries" <bob.nuckolls(at)cox.net>
Subject: RE: AeroElectric-List: Essential bus alternate feed from two bat
teries
bat teries
>
> >
> >
> > batteries
> >
> >
> > >During start I thought I would use the main battery for cranking
engine,
> > >the aux battery for powering the electronic ignition (to avoid any
> > >possibility of kick back in the event main battery voltage drops below
> > >min required for electronic ignition).
> >
> > ???? Is it the stated policy/recommendation by the manufacturer
> > of the ignition system that you do this? I'm increasingly mystified
> > by what I perceive as an upsurge in worries about this. Perhaps
> > it's just that the economy is improving and more folks are building
> > airplanes with electronic ignition. Market forces notwithstanding,
> > I'm wondering if the risk is real and whether or not the
manufacturers
> > of these products are acknowledging a shortcoming in their product's
> > design. The low voltage event during cranking is tens of milliseconds
> > long as the starter motor spins up. There is no good reason why
> > you as the user should have to be concerned about this. Designing
> > sensitivity to this phenomenon out of the ignition system is
> > a rudimentary technique of circuit design.
> >
> >Bob,
> >
> >This may be a legitimate "worry". I spent quite a bit of time and energy
> >attempting to resolve the starting problems with my LSE ignition system.
I
> >have a permanent magnet Lycoming starter, a 17 AH battery, and I start
the
> >engine on the electronic ignition only. My engine would only start when
I
> >released the starter button. It always started, but it left me with an
> >uneasy feeling that sometime, far away from home, it may not. The
voltage
> >(measured at the ignition module) drops to around 8 volts with the
starter
> >engaged, and the LSE does not fire at that voltage, regardless of what
> >Klause claims. I resolved the problem for now by switching to an Odyssey
> >battery, which does not produce quite as much voltage drop. A better
> >solution is a B & C starter that draws less current, but that cost $$$.
If
> >I were building an airplane with two batteries, I would certainly
consider
> >starting on one and powering the electronic ignition from the other.
>
> Hmmm. Did you try leaving the ignition switch off until after
> the engine was rotating?
>
> Bob . . .
>
>
________________________________________________________________________________
Subject: | Alternator Wiring Question |
From: | "Metcalfe, Lee, AIR" <Lee.Metcalfe(at)jocogov.org> |
My flying Lancair 320 (not built by me) has an automotive-type,
externally-regulated alternator with absolutely no identifying markings
on it other than "Made In Japan" and identifiers next to the
connections. The alternator is a belt-driven, boss-mount type on a Lyc
320. It has binding posts for all connections plus a provision for a
three-spade connector, which is where it is connected to the regulator
in this particular installation. Here is the shape of the connector and
the markings...
E
_____
| ___ |
__| |__
| |
| | | |
| | | |
| |
-------------
F N
The N spade is unused. The F spade is connected to the "FLD" connection
on the regulator. The E spade is connected to the case ground of the
regulator (mounted on the firewall).
My question is, what is the purpose of the E connection, and is it
necessary? I ask because I'm about to swap out the generic
automotive-type regulator for a B&C LR3C and need to know whether I need
to keep that E connection and why.
Lee Metcalfe
N320WH - Kansas City
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Flap motor testing |
>
>
>I run a Cessna flap motor with 10A fuse in my RV4, and have bent the
>actuating rods without ever blowing a fuse!
>Ken Melvin
>N36KM
Which doesn't surprise me. The mechanical advantage
that motor has is phenomenal . . . the problem isn't
one of TORQUE from the motor but INRUSH currents
presented by the permanent magnet motor in the milliseconds
after application of power but before it develops much
speed.
Bob . . .
________________________________________________________________________________
From: | "Ed Anderson" <eanderson(at)carolina.rr.com> |
Subject: | Re: Electric fuel pump circuit |
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Electric fuel pump circuit
>
> >
> >Bob,
> > I was hoping you'd say that. (forget the relay) Do I understand you
> > correctly? You feel the pump should be wired to the battery bus?
> >Charlie
>
> I think I would. There's some compelling thought for being
> able to make the panel completely dark without affecting
> anything needed to keep the engine running.
>
> Bob . . .
I agree with Bob. My rotary powered RV-6A has all critical items, fuel
pump, ignition and fuel injection system wired off the battery bus. Only
thing between the subsystems and the battery is a high grade toggle switch
and circuit breaker. Then being somewhat anal retentive about failure of
mechanical switches, I hot wire all these subsystems to the battery through
one 20 amp circuit breaker which is normally open. If you push in the
circuit breaker it routes power around all switches to the critical systems.
Never had to use it (and probably never will) but it is comforting and light
and cheap to implement.
Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
________________________________________________________________________________
From: | "Eric M. Jones" <emjones(at)charter.net> |
Load Dump occurs anytime the generator sheds its load (like turning
something off), because the generator/alternator stator must reduce its
magnetic field. This takes a while---almost half-a-second in the worst case.
Load Dump is at it's worst when nothing but a flat battery is being honked
on by the alternator/ generator and every other load is off---THEN the
battery gets disconnected.
I've been watching this load dump stuff with interest. I designed a
combination lightning suppressor and load dump suppressor which will see the
light of day soon. But I could not calculate the energy sufficiently to size
the Transient Voltage Suppressor network. But realistically the automotive
people had this figured out a long time ago. The chief document seems to be
SAE J1113-11 but you have to pay big bucks to get a look at it, and there's
that secret pledge thingy.... But the other guys have published standards
which presumably are technically close, and they can be found online.
Standard Open-Circuit Volts Rise Time (10%-90%) Pulse duration
(10%-10%)
SAE J1113-11 ???? ???? ????
Chrysler PF9326 91.5 V 5-10 mS 300 mS
Ford CL240 60 V 1-10 mS 300 mS
ISO 7637 ?? 5-10 mS 50-400 mS
All these standards presume a quick rise from nominal to some higher
voltage, then a slower exponential decay back to the nominal base. So they
have the similar graphs but different values. All these standards also have
a particular repetition rate, a load impedance, and some minor details, but
they are quite similar.
Chrysler standard PF9326 (good published information can be found online)
presumes there is some load on the system. There is a circuit called the
"Load Dump Vehicle Suppression Model" that simulates what one would expect
to find in a real-world vehicle (whether or not it keeps its wheels on the
ground.).
According to the Chrysler standard, the peak voltage under these condition
is 38 volts for a nominal operating voltage of 13.5V and of course a load
given by the LDVSM, but about 0.5 ohms..
To properly design a system to squash this stuff we need to know the worst
case system energy (in Joules), which, we all remember, is a Watt-second.
These are hard numbers to come by, but we can tease them out of the
published data: Chrysler presumes a Load Dump pulse of 91.5 Volts into a 0.5
ohm load. The 91.5 volts is the alternator/generator potential, and the peak
current is therefore 91.5/0.5=183 Amps. And peak watts (power) is therefore
16.7 kW. The exponential decay is 0.300 Seconds. So that's (...are you
following this?) 16.7 kW X 0.300 S=5 kW seconds X the correction factor for
the exponential decay which is about 1/3-1/2. So we can use a 2.5 kW(S)
Transient Voltage Suppressor. If we use two we buy a little margin.
George's experience with a 5 kW TVS blowing up....I don't know, but if it
was across the generator or close enough so that the 0.5 ohms didn't
apply...ka-blammmm.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"I only regret my economies."
Reynolds Price
________________________________________________________________________________
From: | Jerzy Krasinski <krasinski(at)provalue.net> |
Eric,
I do not think this calculation is right.
I think we should model the alternator as an inductivity with current.
After opening the circuit the inductivity increases output voltage
attemting to keep the output current constant, with gradual reduction
of current as the energy from the inductivity is dissipated.
This model, produces output current equal or less than the alternator
output current just before disconnecting action.
I can not find a single reason why the alternator would suddenly like to
increase the output current to some unrealistic values, at the same
time increasing the output voltage. Inductivities do not behave that way.
A transorg is to small, It seems that coupling a transorb with a high
power bipolar or mosfet transistor could be the way to go. Definitely a
large transistor can take much more power than a small transorb. A npn
transistor powerful enough to take 50A or may be 100A current at 14 V
for the required time of say 0.1s is needed. Connect a 14 V transorb
or a zener diode between collector and base. Connect collector to the +
output of the alternator, and ground the emiter. Now it is the
transistor rather than the transorb taking most of the current. There
are many high power transistors to choose from, and prices for low
voltage transistors are low .
Jerzy
Eric M. Jones wrote:
>
>Load Dump occurs anytime the generator sheds its load (like turning
>something off), because the generator/alternator stator must reduce its
>magnetic field. This takes a while---almost half-a-second in the worst case.
>Load Dump is at it's worst when nothing but a flat battery is being honked
>on by the alternator/ generator and every other load is off---THEN the
>battery gets disconnected.
>
>I've been watching this load dump stuff with interest. I designed a
>combination lightning suppressor and load dump suppressor which will see the
>light of day soon. But I could not calculate the energy sufficiently to size
>the Transient Voltage Suppressor network. But realistically the automotive
>people had this figured out a long time ago. The chief document seems to be
>SAE J1113-11 but you have to pay big bucks to get a look at it, and there's
>that secret pledge thingy.... But the other guys have published standards
>which presumably are technically close, and they can be found online.
>
>Standard Open-Circuit Volts Rise Time (10%-90%) Pulse duration
>(10%-10%)
>
>SAE J1113-11 ???? ???? ????
>Chrysler PF9326 91.5 V 5-10 mS 300 mS
>Ford CL240 60 V 1-10 mS 300 mS
>ISO 7637 ?? 5-10 mS 50-400 mS
>
>All these standards presume a quick rise from nominal to some higher
>voltage, then a slower exponential decay back to the nominal base. So they
>have the similar graphs but different values. All these standards also have
>a particular repetition rate, a load impedance, and some minor details, but
>they are quite similar.
>
>Chrysler standard PF9326 (good published information can be found online)
>presumes there is some load on the system. There is a circuit called the
>"Load Dump Vehicle Suppression Model" that simulates what one would expect
>to find in a real-world vehicle (whether or not it keeps its wheels on the
>ground.).
>
>According to the Chrysler standard, the peak voltage under these condition
>is 38 volts for a nominal operating voltage of 13.5V and of course a load
>given by the LDVSM, but about 0.5 ohms..
>
>To properly design a system to squash this stuff we need to know the worst
>case system energy (in Joules), which, we all remember, is a Watt-second.
>These are hard numbers to come by, but we can tease them out of the
>published data: Chrysler presumes a Load Dump pulse of 91.5 Volts into a 0.5
>ohm load. The 91.5 volts is the alternator/generator potential, and the peak
>current is therefore 91.5/0.5=183 Amps. And peak watts (power) is therefore
>16.7 kW. The exponential decay is 0.300 Seconds. So that's (...are you
>following this?) 16.7 kW X 0.300 S=5 kW seconds X the correction factor for
>the exponential decay which is about 1/3-1/2. So we can use a 2.5 kW(S)
>Transient Voltage Suppressor. If we use two we buy a little margin.
>
>George's experience with a 5 kW TVS blowing up....I don't know, but if it
>was across the generator or close enough so that the 0.5 ohms didn't
>apply...ka-blammmm.
>
>Regards,
>Eric M. Jones
>www.PerihelionDesign.com
>113 Brentwood Drive
>Southbridge MA 01550-2705
>Phone (508) 764-2072
>Email: emjones(at)charter.net
>
>"I only regret my economies."
> Reynolds Price
>
>
>
>
________________________________________________________________________________
Subject: | Flap Schematic Question |
From: | "Grosvenor, Gary L [CC]" <Gary.Grosvenor(at)mail.sprint.com> |
Bob - Here's a newbie question for you but please forgive my parochial cerebral
base. I was studying your flap schematic.
Question: What are the inverted triangle symbols with the letter L in them? These
symbols are at the end of what I think are conductors coming off a connection
point on the retract and extend relays.
Thanks so much for your expertise and willingness to share!
I'm still tryin' to learn the lingo.
Gary
________________________________________________________________________________
From: | Larry Colley <larry(at)grrok.com> |
Subject: | Heat Shrink on Coax |
I have seen notes stating not to use heat shrink tubing on coax because the
heat will destroy the coax insulation. ??Does this apply to both RG58 and
RG400??
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Emergency Buss/Standby Alternator |
>
>
>Bob,
>
>I have a 71 V35B Bonanza which I am in process of modifying the instrument
>panel and the electrical system to improve it's IFR capability and
>incorporate some backup systems. The original main bus (copper strip) was
>cut and a separate avionics bus is now supplied through a 35amp breaker
>switch via a 10 gauge wire. I have added an electric attitude indicator as
>a backup for a vacuum failure and am planning on installing the B&C 20amp
>standby alternator system. Even though this is not an OBAM aircraft, as an
>A&P/IA I do all the modifications and maintenance. I would welcome your
>opinion about some questions I have and others might be interested as well.
>
>I would like to install an emergency buss with an always-hot feed off the
>battery bus as a backup and to eliminate the single-point-of-failure
>avionics switch.
Why a separate bus? Make your current "avionics" bus an endurance
bus, ad a diode in series with the current avionics master so as
to avoid inadvertent back-feeding of the bus via alternate feed.
Then add an alternate feedpath from the battery. The fuse will be
bigger than 5A so to satisfy the feds you'll need the disconnect
relay shown in:
http://www.aeroelectric.com/temp/E-BusFatFeed.gif
> The EB would have numerous items, including an S-Tec 50
>AP, (removed from the existing avionics and main bus) with a total MAX
>current of nearly 20amp. Typical current would be more like 12amp, or less
>if load was shed. The EB would be supplied with a 12ga wire/16ga fusible
>link through a 20amp (or maybe 15a) breaker switch and normally through the
>D-25 essential bus diode from the main or avionics bus automatically. I
>would like the breaker switch to open before the fusible link fails so that
>load could be shed and then the switch could be closed again.
>
>1. Is the idea of having an EB even worthwhile if I incorporate the B&C
>standby alternator system?
This is a big change as far as the feds are concerned. You'll need
an STC. The B&C standby alternator is easy to get approved (it has
an STC) so having dual feedpaths for the e-bus is the only thing
you need to add . . . even THAT may get you up to your eyeballs in
paperwork . . . but it's as effective as a whole new bus structure
and easy to install.
>2. If it is, or if I don't incorporate the B&C alternator, does the D-25
>essential bus diode have the capacity to handle the proposed current in the
>normal direction? I assume this is the easiest way to supply the EB and the
>0.6v drop is of no concern?
Correct. Mount the diode on 25 square inches of aluminum surface
or more to dump the heat.
>3. How would the D-25 fail if it did? Open circuit or what?
It generally shorts (you need to preflight test this) and if it
opens, you have the alternate feed path.
>4. Is there a better way to protect the always-hot feed line such as with a
>20amp current limiter (I haven't seen any with that low of rating)?
>5. If I don't incorporate the EB should I install another breaker-switch in
>parallel with the existing avionics master switch to eliminate the
>single-point-of-failure?
>
>Although the B&C system is STC'd for the Bonanza, would the addition of an
>emergency buss constitute a major alteration in your opinion (changes to the
>basic design of the electrical system - per FAR Part 43, Appendix A)?
If you made your airplane look like figure Z-12 except you add
relay cited above, we're not going to read any dark-n-stormy-night
stories authored by you about how your electrical system came
up short.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Alternator Wiring Question |
>
>
>My flying Lancair 320 (not built by me) has an automotive-type,
>externally-regulated alternator with absolutely no identifying markings
>on it other than "Made In Japan" and identifiers next to the
>connections. The alternator is a belt-driven, boss-mount type on a Lyc
>320. It has binding posts for all connections plus a provision for a
>three-spade connector, which is where it is connected to the regulator
>in this particular installation. Here is the shape of the connector and
>the markings...
>
> E
> _____
> | ___ |
> __| |__
>| |
>| | | |
>| | | |
>| |
>-------------
> F N
>
>The N spade is unused. The F spade is connected to the "FLD" connection
>on the regulator. The E spade is connected to the case ground of the
>regulator (mounted on the firewall).
>
>My question is, what is the purpose of the E connection, and is it
>necessary? I ask because I'm about to swap out the generic
>automotive-type regulator for a B&C LR3C and need to know whether I need
>to keep that E connection and why.
I'm guessing but I'll suggest the "E" is the ground connection
for the second field brush. Leave it in place to use the
LR3 regulator.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Load Dump occurs anytime the generator sheds its load (like turning
>something off), because the generator/alternator stator must reduce its
>magnetic field. This takes a while---almost half-a-second in the worst case.
>Load Dump is at it's worst when nothing but a flat battery is being honked
>on by the alternator/ generator and every other load is off---THEN the
>battery gets disconnected.
>
>I've been watching this load dump stuff with interest. I designed a
>combination lightning suppressor and load dump suppressor which will see the
>light of day soon. But I could not calculate the energy sufficiently to size
>the Transient Voltage Suppressor network. But realistically the automotive
>people had this figured out a long time ago. The chief document seems to be
>SAE J1113-11 but you have to pay big bucks to get a look at it, and there's
>that secret pledge thingy.... But the other guys have published standards
>which presumably are technically close, and they can be found online.
>
>Standard Open-Circuit Volts Rise Time (10%-90%) Pulse duration
>(10%-10%)
>
>SAE J1113-11 ???? ???? ????
>Chrysler PF9326 91.5 V 5-10 mS 300 mS
>Ford CL240 60 V 1-10 mS 300 mS
>ISO 7637 ?? 5-10 mS 50-400 mS
>
>All these standards presume a quick rise from nominal to some higher
>voltage, then a slower exponential decay back to the nominal base. So they
>have the similar graphs but different values. All these standards also have
>a particular repetition rate, a load impedance, and some minor details, but
>they are quite similar.
>
>Chrysler standard PF9326 (good published information can be found online)
>presumes there is some load on the system. There is a circuit called the
>"Load Dump Vehicle Suppression Model" that simulates what one would expect
>to find in a real-world vehicle (whether or not it keeps its wheels on the
>ground.).
>
>According to the Chrysler standard, the peak voltage under these condition
>is 38 volts for a nominal operating voltage of 13.5V and of course a load
>given by the LDVSM, but about 0.5 ohms..
>
>To properly design a system to squash this stuff we need to know the worst
>case system energy (in Joules), which, we all remember, is a Watt-second.
>These are hard numbers to come by, but we can tease them out of the
>published data: Chrysler presumes a Load Dump pulse of 91.5 Volts into a 0.5
>ohm load. The 91.5 volts is the alternator/generator potential, and the peak
>current is therefore 91.5/0.5=183 Amps. And peak watts (power) is therefore
>16.7 kW. The exponential decay is 0.300 Seconds. So that's (...are you
>following this?) 16.7 kW X 0.300 S=5 kW seconds X the correction factor for
>the exponential decay which is about 1/3-1/2. So we can use a 2.5 kW(S)
>Transient Voltage Suppressor. If we use two we buy a little margin.
>
>George's experience with a 5 kW TVS blowing up....I don't know, but if it
>was across the generator or close enough so that the 0.5 ohms didn't
>apply...ka-blammmm.
I'm suspicious of how a device rated to produce 50A output
and magnetically limited to some value just above that
can produce a 183A spike . . .
I suspect we're going to find that 90v is open circuit, and that
when the transient is clamped off at some lower level that the
current is no higher than what the alternator puts out.
Total energy is still the key. Consider the battery-dump under
consideration: An heavily loaded alternator with built in regulator
is unhooked from the battery. The alternator isn't defective
before the event. NOW . . . it's running self excited into an
open circuit. I suspect this event is neither inductive or transient
(short duration typical of an L/R or R-C timed event).
The big question is how the alternator's built in regulator behaves.
If the regulator can open the field circuit before voltages get
so high that the regulator itself is damaged, then everything
comes to rest in an orderly manner. Depending on response time
of the REGULATOR, the TVS has to grunt 50A or so of current for
DURATION OF RESPONSE TIME . . . this is how George's TVS got
launched into orbit.
Response time can be a huge variable from one make of regulator
to the next. I'm hoping that we can deduce enough information
from the testing to modify recommendations for implementing
Z-24 with some degree of comfort. If not (and the pilot
really feels a need to flip alternator switches on and off
while the engine is running), then I may have to retreat
to the original philosophy of recommending that airplanes
fly only with externally regulated alternators.
Keep in mind that the investigation before us is needed
only to protect an alternator from the pilot. Z-24 provides
the ov protection desired for the rest of the system and
becomes problematical only if switches are operated
unnecessarily and at inappropriate times. Figure Z-24 is
going to disconnect an alternator wherein the regulator
has ALREADY FAILED. Anyone with Z-24 up and running
has no cause for concerns as long as he/she operates
the alternator in a manner that is consistent
with 99.999% of the flights conducted every day.
Bob . . .
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
GREAT INFO.
Given the normal connection of the alternator directly connected to the main
bus and the battery connected via a contactor to the same bus; IF the
battery is disconnected when taking a charge we get the load dump and the
voltage on the main bus rises to what ever it takes until that charge
current is consumed. This can result in what ever is "ON" at the time seeing
very high voltages (compared to their rated max) and for durations much
longer than they are designed to accommodate. Ref your data.
Use of a TVS should keep the current to no more than the "dumped" current
(it seems to me) so in that respect I question that part of your info.
However shorting to ground with low resistance can cause higher momentary
currents as you suggest. The use of a TVS will not provide a simple 0.5 ohm
load but provides a simulated battery so the alternator "sees" the removal
of the battery as a slight increase in the output voltage and the TVS simply
dumps the excess current at the expense of the higher "BUS" voltage. The
alternator does not see a load dump in this case, just a slight jump in the
load voltage. In a non failed condition the regulator takes over and the
voltage returns to normal. The TVS bridges the time between the battery
removal and the response by the regulator.
This higher bus voltage may trigger the OVP circuit and terminates the
energy and limits the heat in the TVS to prevent damage to the TVS.
Thus we need both designs in a system. The TVS keeps the voltage down and
the OVP shuts the alternator down (in severe cases).
The TVS is designed to short if it over heats and that short will open blow
the in line fuse "Bob" shows in the "B" lead if the OVP fails or the
alternator has failed.
This leaves the question of what the bus voltage rises to during the load
dump.
I have experimented with 5KW 18V and it clamps fine but at a voltage above
20V (more data in a few days). It does appear that the voltage will rise to
above the max at least for some of my equipment.
This is the final concern to me. That is limiting the bus "over voltage" to
what the attached equipment can tolerate. A few milliseconds is typically
tolerated in the devices input circuit filters but your 200-300 ms duration
may not be tolerated.
At least the above is how I see the problem.
Paul
----- Original Message -----
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: AeroElectric-List: Re: Load Dumps
>
> Load Dump occurs anytime the generator sheds its load (like turning
> something off), because the generator/alternator stator must reduce its
> magnetic field. This takes a while---almost half-a-second in the worst
case.
> Load Dump is at it's worst when nothing but a flat battery is being honked
> on by the alternator/ generator and every other load is off---THEN the
> battery gets disconnected.
>
> I've been watching this load dump stuff with interest. I designed a
> combination lightning suppressor and load dump suppressor which will see
the
> light of day soon. But I could not calculate the energy sufficiently to
size
> the Transient Voltage Suppressor network. But realistically the automotive
> people had this figured out a long time ago. The chief document seems to
be
> SAE J1113-11 but you have to pay big bucks to get a look at it, and
there's
> that secret pledge thingy.... But the other guys have published standards
> which presumably are technically close, and they can be found online.
>
> Standard Open-Circuit Volts Rise Time (10%-90%) Pulse duration
> (10%-10%)
>
> SAE J1113-11 ???? ???? ????
> Chrysler PF9326 91.5 V 5-10 mS 300 mS
> Ford CL240 60 V 1-10 mS 300 mS
> ISO 7637 ?? 5-10 mS 50-400 mS
>
> All these standards presume a quick rise from nominal to some higher
> voltage, then a slower exponential decay back to the nominal base. So they
> have the similar graphs but different values. All these standards also
have
> a particular repetition rate, a load impedance, and some minor details,
but
> they are quite similar.
>
> Chrysler standard PF9326 (good published information can be found online)
> presumes there is some load on the system. There is a circuit called the
> "Load Dump Vehicle Suppression Model" that simulates what one would expect
> to find in a real-world vehicle (whether or not it keeps its wheels on the
> ground.).
>
> According to the Chrysler standard, the peak voltage under these condition
> is 38 volts for a nominal operating voltage of 13.5V and of course a load
> given by the LDVSM, but about 0.5 ohms..
>
> To properly design a system to squash this stuff we need to know the worst
> case system energy (in Joules), which, we all remember, is a Watt-second.
> These are hard numbers to come by, but we can tease them out of the
> published data: Chrysler presumes a Load Dump pulse of 91.5 Volts into a
0.5
> ohm load. The 91.5 volts is the alternator/generator potential, and the
peak
> current is therefore 91.5/0.5=183 Amps. And peak watts (power) is
therefore
> 16.7 kW. The exponential decay is 0.300 Seconds. So that's (...are you
> following this?) 16.7 kW X 0.300 S=5 kW seconds X the correction factor
for
> the exponential decay which is about 1/3-1/2. So we can use a 2.5 kW(S)
> Transient Voltage Suppressor. If we use two we buy a little margin.
>
> George's experience with a 5 kW TVS blowing up....I don't know, but if it
> was across the generator or close enough so that the 0.5 ohms didn't
> apply...ka-blammmm.
>
> Regards,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones(at)charter.net
>
> "I only regret my economies."
> Reynolds Price
>
>
________________________________________________________________________________
From: | "flyv35b" <flyv35b(at)ashcreekwireless.com> |
Subject: | Re: Emergency Buss/Standby Alternator |
> Why a separate bus? Make your current "avionics" bus an endurance
> bus, ad a diode in series with the current avionics master so as
> to avoid inadvertent back-feeding of the bus via alternate feed.
> Then add an alternate feedpath from the battery. The fuse will be
> bigger than 5A so to satisfy the feds you'll need the disconnect
> relay shown in:
>
> http://www.aeroelectric.com/temp/E-BusFatFeed.gif
Yes, that would be simpler. Why is 5amp the maximum that the FAA seems to
be happy with on always-hot feed lines? If that is the case why not run 3
separate wires that are each fused (5amp) and connect them together at the
EB to feed it a total of 15amp? Would this keep the FAA happy?
Thanks for your advice.
Cliff
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Emergency Buss/Standby Alternator
>
> >
> >
> >Bob,
> >
> >I have a 71 V35B Bonanza which I am in process of modifying the
instrument
> >panel and the electrical system to improve it's IFR capability and
> >incorporate some backup systems. The original main bus (copper strip)
was
> >cut and a separate avionics bus is now supplied through a 35amp breaker
> >switch via a 10 gauge wire. I have added an electric attitude indicator
as
> >a backup for a vacuum failure and am planning on installing the B&C 20amp
> >standby alternator system. Even though this is not an OBAM aircraft, as
an
> >A&P/IA I do all the modifications and maintenance. I would welcome your
> >opinion about some questions I have and others might be interested as
well.
> >
> >I would like to install an emergency buss with an always-hot feed off the
> >battery bus as a backup and to eliminate the single-point-of-failure
> >avionics switch.
>
> Why a separate bus? Make your current "avionics" bus an endurance
> bus, ad a diode in series with the current avionics master so as
> to avoid inadvertent back-feeding of the bus via alternate feed.
> Then add an alternate feedpath from the battery. The fuse will be
> bigger than 5A so to satisfy the feds you'll need the disconnect
> relay shown in:
>
> http://www.aeroelectric.com/temp/E-BusFatFeed.gif
>
> > The EB would have numerous items, including an S-Tec 50
> >AP, (removed from the existing avionics and main bus) with a total MAX
> >current of nearly 20amp. Typical current would be more like 12amp, or
less
> >if load was shed. The EB would be supplied with a 12ga wire/16ga fusible
> >link through a 20amp (or maybe 15a) breaker switch and normally through
the
> >D-25 essential bus diode from the main or avionics bus automatically. I
> >would like the breaker switch to open before the fusible link fails so
that
> >load could be shed and then the switch could be closed again.
> >
> >1. Is the idea of having an EB even worthwhile if I incorporate the B&C
> >standby alternator system?
>
> This is a big change as far as the feds are concerned. You'll need
> an STC. The B&C standby alternator is easy to get approved (it has
> an STC) so having dual feedpaths for the e-bus is the only thing
> you need to add . . . even THAT may get you up to your eyeballs in
> paperwork . . . but it's as effective as a whole new bus structure
> and easy to install.
>
> >2. If it is, or if I don't incorporate the B&C alternator, does the D-25
> >essential bus diode have the capacity to handle the proposed current in
the
> >normal direction? I assume this is the easiest way to supply the EB and
the
> >0.6v drop is of no concern?
>
> Correct. Mount the diode on 25 square inches of aluminum surface
> or more to dump the heat.
>
> >3. How would the D-25 fail if it did? Open circuit or what?
>
> It generally shorts (you need to preflight test this) and if it
> opens, you have the alternate feed path.
>
> >4. Is there a better way to protect the always-hot feed line such as
with a
> >20amp current limiter (I haven't seen any with that low of rating)?
> >5. If I don't incorporate the EB should I install another breaker-switch
in
> >parallel with the existing avionics master switch to eliminate the
> >single-point-of-failure?
> >
> >Although the B&C system is STC'd for the Bonanza, would the addition of
an
> >emergency buss constitute a major alteration in your opinion (changes to
the
> >basic design of the electrical system - per FAR Part 43, Appendix A)?
>
> If you made your airplane look like figure Z-12 except you add
> relay cited above, we're not going to read any dark-n-stormy-night
> stories authored by you about how your electrical system came
> up short.
>
> Bob . . .
>
>
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Emergency Buss/Standby Alternator |
>
>
> > Why a separate bus? Make your current "avionics" bus an endurance
> > bus, ad a diode in series with the current avionics master so as
> > to avoid inadvertent back-feeding of the bus via alternate feed.
> > Then add an alternate feedpath from the battery. The fuse will be
> > bigger than 5A so to satisfy the feds you'll need the disconnect
> > relay shown in:
> >
> > http://www.aeroelectric.com/temp/E-BusFatFeed.gif
>
>Yes, that would be simpler. Why is 5amp the maximum that the FAA seems to
>be happy with on always-hot feed lines?
Crash safety.
> If that is the case why not run 3
>separate wires that are each fused (5amp) and connect them together at the
>EB to feed it a total of 15amp? Would this keep the FAA happy?
No. A fault anywhere downstream of the fuse array
can produce current flows and durations in excess
of that which a single 5A fuse would offer.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Heat Shrink on Coax |
>
>I have seen notes stating not to use heat shrink tubing on coax because the
>heat will destroy the coax insulation. ??Does this apply to both RG58 and
>RG400??
No, only the RG58 which uses 1940's era plastics. Any modern
coax which includes RG-400/RG-142 styles.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Flap Schematic Question |
>
>
>Bob - Here's a newbie question for you but please forgive my parochial
>cerebral base. I was studying your flap schematic.
>
>Question: What are the inverted triangle symbols with the letter L in
>them? These symbols are at the end of what I think are conductors coming
>off a connection point on the retract and extend relays.
>
>Thanks so much for your expertise and willingness to share!
>I'm still tryin' to learn the lingo.
Yup, most folks come into this arena with the belief that
that technology is the biggest barrier to understanding.
Whether you're working to become a chef or electronic technician, the
biggest barrier to understanding is language. Every fundamental
of cooking or assembling an electrical system is stone simple.
The science of any activity involves a working knowledge of the
fundamentals which includes learning a new language.
After that, the art of assembling simple-ideas into useful
products is easy, fun and limited only by your willingness
to exercise critical thought. And it IS an art for there
are many ways to assemble the simple-ideas into serviceable
systems.
Check out Chapter 1 of the 'Connection at:
http://www.aeroelectric.com/articles/Rev10/ch1.pdf
Figure 16 of this chapter speaks to the symbol you've
cited above along with an illustration of how it can
be labeled to show where it connects to the system. In
the case of an "L", I'm suggesting that this is a
"local" ground.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>I can not find a single reason why the alternator would suddenly like to
>increase the output current to some unrealistic values, at the same
>time increasing the output voltage. Inductivities do not behave that way.
The alternator is the energy source but only because of what
it's being told to do by the regulator . . .
>A transorg is to small, It seems that coupling a transorb with a high
>power bipolar or mosfet transistor could be the way to go. Definitely a
>large transistor can take much more power than a small transorb. A npn
>transistor powerful enough to take 50A or may be 100A current at 14 V
>for the required time of say 0.1s is needed. Connect a 14 V transorb
>or a zener diode between collector and base. Connect collector to the +
>output of the alternator, and ground the emiter. Now it is the
>transistor rather than the transorb taking most of the current. There
>are many high power transistors to choose from, and prices for low
>voltage transistors are low .
We looked at this at Cessna back in the 60's . . . The "FAT" transistor
of choice was the 2N174
http://www.pemberton.electronics.btinternet.co.uk/transistors/2n/2N174.html
and the fact that it was a PNP device made it easier to install.
The metal case (collector) could be bolted right to the airframe.
We built it up and showed that it would "grab spikes". I left
about that time and I don't recall if it ever found its way onto
the airplanes. I don't think it did. Some bean counter probably
asked, "what is the return on investment for adding this feature
to our products?" Unless he/she got a satisfactory answer, it
didn't happen. Given our level of understanding at that time,
I suspect it never made it to the production line.
You're correct in your suggestion that modern transistors are
capable of grunting some big currents. It may be that the
elegant solution would include a fat transistor.
Bob . . .
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
---- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Re: Load Dumps
> The big question is how the alternator's built in regulator behaves.
> If the regulator can open the field circuit before voltages get
> so high that the regulator itself is damaged, then everything
> comes to rest in an orderly manner. Depending on response time
> of the REGULATOR, the TVS has to grunt 50A or so of current for
> DURATION OF RESPONSE TIME . . . this is how George's TVS got
> launched into orbit.
>
> Response time can be a huge variable from one make of regulator
> to the next. I'm hoping that we can deduce enough information
> from the testing to modify recommendations for implementing
> Z-24 with some degree of comfort. If not (and the pilot
> really feels a need to flip alternator switches on and off
> while the engine is running), then I may have to retreat
> to the original philosophy of recommending that airplanes
> fly only with externally regulated alternators.
I do not see how there is any basic difference (with regard to LOAD DUMP)in
internally regulated VS externally regulated Alternators; in the case of the
Battery contactor opening up from either pilot operation (other than
progressive switch use) or simply contactor failure. Either way IF the
alternator is charging the battery at that time, you end up with a partial
load dump as some of the load is supporting the acft systems thru the main
bus. The response time of the regulator will vary as you have said but there
is still a load dump, of some magnitude, in ALL cases that needs to be
addressed.
As the OVP simply takes the alternator off line by cutting the field and/or
allowing the "B" lead contactor to open there is still a few ms reaction
time in the contactor and the energy is dumping for that time.
Either way the TVS current is limited to a few ms and can be tolerated by
the proper TVS. however the TVS may allow a few ms of relatively HV to
appear on the main buss that can exceed the equipment ratings.
> Keep in mind that the investigation before us is needed
> only to protect an alternator from the pilot. Z-24 provides
> the ov protection desired for the rest of the system and
> becomes problematical only if switches are operated
> unnecessarily and at inappropriate times. Figure Z-24 is
> going to disconnect an alternator wherein the regulator
> has ALREADY FAILED. Anyone with Z-24 up and running
> has no cause for concerns as long as he/she operates
> the alternator in a manner that is consistent
> with 99.999% of the flights conducted every day.
>
> Bob . . .
Mostly agree on Z-24, however, protection from pilot is only part of the
concern. I really do not like the use of procedures to prevent equipment
damage. Throwing the incorrect switch should never cause damage!
I am addressing a different case. First, not everyone has your progressive
switches; and you do not seem to address contactor failure. (however
unlikely its not zero). The importance of your progressive switch as the key
to your above statement should be included.
Failure of one device should never cause additional failures. I suggest that
a battery contactor failure should not result in a load dump where the
alternator is still connected to the main bus. Regardless of the potential
damage of the alternator regulator the main bus gets the impact of the load
dump and prtection needs to be added in my opinion.
My testing to date has shown to me that the remaining issue is the peak
voltage and duration during the TVS protected load dump VS the ability of
the equipment to tolerate that transient.
Paul
________________________________________________________________________________
From: | "Rogers, Bob J." <BRogers(at)fdic.gov> |
I plan to have an internally regulated 80-amp alternator (from a Mazda RX-7)
as my primary electrical energy source, with a second 35-amp permanent
magnet internally regulated alternator as a back up source of electricity.
I will have only one battery.
I need to be able to test the back-up alternator before I fly, which
involves turning at least one alternator off while the engine is running (or
switching from one alternator to the other). What is the correct procedure
to insure that I do not accidentally destroy an alternator or any other
electrical component of my system?
-----Original Message-----
From: Robert L. Nuckolls, III [mailto:bob.nuckolls(at)cox.net]
Subject: Re: AeroElectric-List: Re: Load Dumps
Keep in mind that the investigation before us is needed
only to protect an alternator from the pilot. Z-24 provides
the ov protection desired for the rest of the system and
becomes problematical only if switches are operated
unnecessarily and at inappropriate times. Figure Z-24 is
going to disconnect an alternator wherein the regulator
has ALREADY FAILED. Anyone with Z-24 up and running
has no cause for concerns as long as he/she operates
the alternator in a manner that is consistent
with 99.999% of the flights conducted every day.
Bob . . .
RE: AeroElectric-List: Re: Load Dumps
I plan to have an internally regulated 80-amp alternator (from a Mazda RX-7) as
my primary electrical energy source, with a second 35-amp permanent magnet internally
regulated alternator as a back up source of electricity. I will have
only one battery.
I need to be able to test the back-up alternator before I fly, which involves turning
at least one alternator off while the engine is running (or switching from
one alternator to the other). What is the correct procedure to insure that
I do not accidentally destroy an alternator or any other electrical component
of my system?
-----Original Message-----
From: Robert L. Nuckolls, III [mailto:bob.nuckolls(at)cox.net]
Subject: Re: AeroElectric-List: Re: Load Dumps
snip
Keep in mind that the investigation before us is needed
only to protect an alternator from the pilot. Z-24 provides
the ov protection desired for the rest of the system and
becomes problematical only if switches are operated
unnecessarily and at inappropriate times. Figure Z-24 is
going to disconnect an alternator wherein the regulator
has ALREADY FAILED. Anyone with Z-24 up and running
has no cause for concerns as long as he/she operates
the alternator in a manner that is consistent
with 99.999% of the flights conducted every day.
Bob . . .
________________________________________________________________________________
Anyone have a source for a good alternator? (Other than B&C.) I want a good
alternator that is NOT internally regulated. Price is not important, you
usually
get what you pay for. 40 or 60 amp. for Lyc. O320.
Thank you,
Bob Devaney
________________________________________________________________________________
From: | Benford2(at)aol.com |
In a message dated 2/27/2004 7:26:51 PM Mountain Standard Time,
Bobdeva(at)aol.com writes:
>
> Anyone have a source for a good alternator? (Other than B&C.) I want a good
>
> alternator that is NOT internally regulated. Price is not important, you
> usually
> get what you pay for. 40 or 60 amp. for Lyc. O320.
> Thank you,
> Bob Devaney
>
Hell,, March on down the the local Piper or Cessna dealer and buy ya one. So
what if it cost a few thousand dollars. Remember,,, you get what you pay for.
Well, at least you do building a experimental plane. The certified guys might
as well buy KY jelly by the case.. Ha ha .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | RE: Battery Dumps |
>
>I plan to have an internally regulated 80-amp alternator (from a Mazda RX-7)
>as my primary electrical energy source, with a second 35-amp permanent
>magnet internally regulated alternator as a back up source of electricity.
>I will have only one battery.
>
>I need to be able to test the back-up alternator before I fly, which
>involves turning at least one alternator off while the engine is running (or
>switching from one alternator to the other). What is the correct procedure
>to insure that I do not accidentally destroy an alternator or any other
>electrical component of my system?
The PM alternator is not subject to the phenomenon of
battery-dump spiking. If you have alternator loadmeter
shunts in the output of both alternators, they'll
allow you to monitor individual alternator behavior
during preflight. A low voltage warning light is your
primary first notification of a tired or broken alternator
and will suffice for preflight checks of dual alternators.
Start the engine and turn the PM alternator on first.
Observe that you have output current. If loadmeters are
not installed, observe that your low voltage warning light goes
out when the alternator comes on. Turn the PM alternator
off and the main alternator on. Loadmeter should show
output and the low voltage light should stay off.
There's no operational need for turning the main
alternator off again until time to park the airplane.
At that time system loads should be minimal, the
battery charged and the engine is at idle rpm. Battery
dumps of damaging proportions don't happen under
these conditions.
By the way, I've been making some effort to re-label
the phenomenon under discussion "battery dump"
as opposed to "load dump". In aviation, "load dump"
speaks clearly to the phenomenon excited by
relieving the SYSTEM of a heavy load like hydraulic
pump, windshield heater, etc. We EXPECT to see
system voltage perturbations but in the general
sense, "load dump" is from a system perspective
wherein a battery is a component of stabilizing
influences.
Not trying to be obtuse . . . if I use the
phrase "load dump" during conversation with
my associates in spam-can-land, the image that
pops into their thoughts does not describe what
we're talking about here. The more precise and
less familiar term "battery dump" allows me
to answer their questioning response with a
description brings understanding about a
condition that is seldom (if ever) considered.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Battery dumps |
>
>---- Original Message -----
>From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
>To:
>Subject: Re: AeroElectric-List: Re: Load Dumps
>
>
>
>
> > The big question is how the alternator's built in regulator behaves.
> > If the regulator can open the field circuit before voltages get
> > so high that the regulator itself is damaged, then everything
> > comes to rest in an orderly manner. Depending on response time
> > of the REGULATOR, the TVS has to grunt 50A or so of current for
> > DURATION OF RESPONSE TIME . . . this is how George's TVS got
> > launched into orbit.
> >
> > Response time can be a huge variable from one make of regulator
> > to the next. I'm hoping that we can deduce enough information
> > from the testing to modify recommendations for implementing
> > Z-24 with some degree of comfort. If not (and the pilot
> > really feels a need to flip alternator switches on and off
> > while the engine is running), then I may have to retreat
> > to the original philosophy of recommending that airplanes
> > fly only with externally regulated alternators.
>
>I do not see how there is any basic difference (with regard to LOAD DUMP)in
>internally regulated VS externally regulated Alternators;
The "problem" we're addressing is the fact that some
alternators with built in regulators will shoot themselves
between the eyes if the pilot switches them on/off in Figure
Z-24 with the engine running and with the alternator carrying
some significant load. This generates something akin to
the automotive "load dump" except that effects are
limited to the alternator itself.
Both styles of alternator can be goaded into producing
a battery-dump surge of output voltage, but for everything
except Z-24 wiring this has been a rare event and very
low on the list of concerns. Many more radios have been smoked
for lack of ov protection than for any other reason. Experience
indicates (and DO-160 infers) that once this dragon is adequately
chained down, probability of letting lots of smoke out of your
radios is very low.
>Either way the TVS current is limited to a few ms and can be tolerated by
>the proper TVS. however the TVS may allow a few ms of relatively HV to
>appear on the main buss that can exceed the equipment ratings.
Only if the equipment is not designed to live in the real
world of airplanes (or any other vehicle with a DC power
generation system).
>Mostly agree on Z-24, however, protection from pilot is only part of the
>concern. I really do not like the use of procedures to prevent equipment
>damage. Throwing the incorrect switch should never cause damage!
It's not a procedure . . . it's a rational/natural mode of
operating the airplane. One should not apply rapid full
travel of flight controls above certain published airspeeds . . .
okay as far as procedures go but I've never had occasion or
desire to exercise it. By the same token, I cannot recall a
single time I felt a need to cycle alternator and/or battery
switches for anything other than troubleshooting on the ground
or in the normal course of turning things on during preflight
and turning things off before I park the airplane.
Even then the alternator always goes off first and does NOT have
an internal regulator. You can take ANY certified single with
the infamous split rocker master switch and punch the alternator
and battery off simultaneously by hitting both sides of the
switch. This simultaneously disconnects the battery AND the
alternator field . . . the mechanically linked nature
of the split-rocker COMBINED with the fact that all spam-cans
have externally regulated alternators makes this action a non-
event with respect to battery dump.
>I am addressing a different case. First, not everyone has your progressive
>switches;
Can't help it if the reasoning behind the use of
progressive master switches is misunderstood or ignored.
The split rocker was crafted to address these issues
45 years ago . . . and aside from the fact that it
mounts in a square cornered hole and looks nothing
like the other switches in the panel, there's nothing
"wrong" with the split rocker. It's made by Carling
and has the same guts behind the panel as the 2-10
toggle switch. The spirit and intent of this switch
has stood the test of time quite well even if the
switch itself has been root cause of many unnecessary
replacements for alternators and regulators in spam-cans.
The Z-figures have shown either simultaneous or progressive
disconnection of alternator/battery since day-one. If
someone chooses to wire their airplane like a Bonanza,
well . . .
> and you do not seem to address contactor failure. (however
>unlikely its not zero).
Contactor failure, particularly contactor failure while the
battery presents a substantial portion of the total alternator
load is very rare.
> The importance of your progressive switch as the key
>to your above statement should be included.
>Failure of one device should never cause additional failures. I suggest that
>a battery contactor failure should not result in a load dump where the
>alternator is still connected to the main bus. Regardless of the potential
>damage of the alternator regulator the main bus gets the impact of the load
>dump and prtection needs to be added in my opinion.
The combination of DO-160 qualification and designing electrical
systems constrained to Mil-STD-704 has a pretty good track record
for covering all the bases . . . including battery-dump. If one
chooses to install accessories which are less robust, then there
are certainly new issues to be considered.
>My testing to date has shown to me that the remaining issue is the peak
>voltage and duration during the TVS protected load dump VS the ability of
>the equipment to tolerate that transient.
Can you share a repeatable experiments for the tests and the
data derived therefrom? We've been hashing this topic for
several weeks now but I've yet to see hard data by which
one can make rational recommendations for either part
selection or places where it's a good thing to include
as part of the system design.
Everyone is free to stack as many "firewalls" against the
extraordinary and unexpected as they wish. I try to avoid
recommendations for firewalls in favor of designing the risks
out (which is, in part, what DO-160 is about). I'll be pleased
to have some real hammer-n-tongs data for color and size of the
beast. It will be nice if there's a practical, one-part
solution with sufficient stature to provide a 99% plus
probability for standing off a battery dump event.
It is my intention to document testing along with a rational for
part selection which we'll recommend as an important inclusion
to Figure Z-24. We'll add information specific to this
topic at the next revision to the OV protection chapter
in the 'Connection. Of course, folks are welcome to apply
the technique to any other configuration as they see fit.
As for as my recommendations . . . may I suggest it's hard
to beat Figure Z-11 with a B&C L-40/LR-3 combination that
drives accessories capable of standing off DO-160 defined
stresses WITH or WITHOUT battery dump protection.
This combination of B&C products has amassed something on order
of a million flight hours of experience over the last 15 years.
This represents a whole lot of pilots who have had very few
reasons to worry their electrical systems. I'm confident
that we'll be able to bring a similar level of confidence
to the use of internally regulated alternators but
not until the NUMBERS are known and describe in a way
that anyone else can go verify/confirm as they see fit.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Figure Z-14 and Battery-Dump |
>Comments/Questions: I have installed a dual alt / dual bus system in my RV
>per your design. Is there a failure mode which would make use of the
>X-Feed switch unwise? If so, how do I identify that failure mode prior to
>using the x-feed?
If you have internally regulated alternators and you've
wired with progressive (2-10) or simultaneous (2-3) switching
of alternator/battery in the Master DC power control switches,
there are no combinations of switch operation that generate
a hazards to your system.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Tom Barter" <kesleyel(at)iowatelecom.net> |
Bob,
What is your current recommendation for a loadmeter? Searching the archives indicates
that the loadmeter kits are no longer available. Is there another instrument
available that can be modified to indicate system load rather than the
minus -0 -plus ammeter?
Thanks,
Tom Barter
Kesley, IA
Avid Magnum
________________________________________________________________________________
From: | Matt Jurotich <mjurotich(at)hst.nasa.gov> |
Subject: | Help with Diagnosis |
My already flying when I bought it RV 6 A has a B&C alternator and a
LR3C-14 voltage regulator. The builder used a 10 amp fuse in the Field
line. Some months ago when I had a low battery, an attempt to jump the
battery got a lot of sparks in the vicinity of the LR3C-14. About 3 flying
hours later the fuse blew and we got home on the battery. Today the fuse
blew again. We landed and replaced the fuse. Everything seemed OK during
taxi and run-up, but the fuse blew again shortly after take-off. Got home
on battery again. Since my home airport is in the DC ADIZ this needs to be
fixed properly. Where do I start to look? A short in the field wire is
the first place, what next? Thanks in advance for the help.
Matthew M. Jurotich
NASA/Goddard Space Flight Center
JWST ISIM Systems Engineer
m/c : 443
e-mail mailto: mjurotich(at)hst.nasa.gov
phone : 301-286-5919
fax : 301-286-7021
JWST URL: <http://ngst1.gsfc.nasa.gov>
________________________________________________________________________________
From: | "John Slade" <sladerj(at)bellsouth.net> |
Subject: | Weird LED fuse behavior |
Here's a strange one for someone....
I have those fuses with an LED that lights up when they blow.
When running my engine for the first time I notice that the LED for the fuel
injection computer (on the essential buss) is glowing, and that the glow
changes in intensity with rpm - i.e. I can light it up more by pushing the
throttle. On shut down I find that the fuse is not blown. I'm not seeing any
charge on the buss from the alternator, and I'm wondering if this may have
something to do with it. Perhaps the alternator solenoid is open, but I
can't see how that would affect voltage or cause some sort of reverse flow
effect.
Any ideas anyone?
John Slade
Cozy IV turbo rotary - making noise
________________________________________________________________________________
From: | "Rick Fogerson" <rickf(at)cableone.net> |
Subject: | Fw: Transponder arial location |
----- Original Message -----
From: Rick Fogerson
Subject: Transponder arial location
Hi Bob,
I've got a xpdr arial question for you. I have installed that little 3 inch long
arial with a ball (B&C) belly just aft of the firewall between the exhaust
pipes. The arial would be shielded some in the forward direction by the portion
of the lower cowl where cooling air exits and the exhaust pipes emerge from
the engine compartment. That wasn't a problem when I was going to install the
standard frp cowl but now I thinking of trying to build an aluminum cowl. How
much of a problem do you think this would be?
Thanks,
Rick Fogerson
RV3
Boise, ID
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
Subject: | Re: Battery dumps |
Thanks for your comments.
Embedded comments
Subject: AeroElectric-List: Re: Battery dumps
> >I do not see how there is any basic difference (with regard to LOAD
>>DUMP)in
> >internally regulated VS externally regulated Alternators;
>
> The "problem" we're addressing is the fact that some
> alternators with built in regulators will shoot themselves
> between the eyes if the pilot switches them on/off in Figure
> Z-24 with the engine running and with the alternator carrying
> some significant load. This generates something akin to
> the automotive "load dump" except that effects are
> limited to the alternator itself.
>
> Both styles of alternator can be goaded into producing
> a battery-dump surge of output voltage, but for everything
> except Z-24 wiring this has been a rare event and very
> low on the list of concerns.
Rare is not zero however. I still maintain ANY internal or external
regulator controlled alternator will produce a spike if the load is reduced
suddenly removed or reduced. I do not see how the response time of the
regulator is a major factor as the energy is already there and fast response
regulators will only limit the duration, not the peak of the "dump".
I do not agree that procedure alone is sufficent IF there is a solution that
prevents or clips the spike. Also, I am not addressing alternator regulator
damage but potential damage to the acft electrical systems.
After spending tens of thousands on an acft and then skimping a small amount
on adding an external regulator is to me mind boggling (dittos for low
output strobes).
> Many more radios have been smoked
> for lack of ov protection than for any other reason. Experience
> indicates (and DO-160 infers) that once this dragon is adequately
> chained down, probability of letting lots of smoke out of your
> radios is very low.
I agree but many of us have older equipment that may not have the type of OV
protection (per DO -160) to withstand a large "dump" where the voltage
'seems' to get well over 40 V with a simple 5kw 18v device and a 40 amp
dump. I have not fully instrumented it as yet.
Limiting the selection of equipment to certified to DO-160 is not affordable
in many cases.
I only have the materials and time to test my own alternator etc and do not
have a ND internal W/WO external alternator. Thus you may get very
different results. Sorry but every alternator is likely to be somewhat
different.
However, if you have a load bank that can handle 14V at 40 amps and use a
contactor to drop the load you can see what the "dump" is.
I have had no damage with the 5kw 18v device I am using in my setup but
another poster has had failures perhaps only due to the test setup. I am not
placing the TVS at the alternator but several feet away on the power bus
distribution and as such have some series resistance external to the
alternator.
Nor do I have the time (or interest) to try to see if all my equipment will
withstand the resulting OV on the bus. My intent is to clamp the OV at its
source and or prevent the dump from happening in the first place.
I think we agree that if the battery is never taken off line while being
charged, there will be no dump. Other than contactor failure your designs
prevent that IF fully followed. The problem is where a builder fails to see
the reason for your design detail and changes it.
>>s and can be tolerated by
> >the proper TVS. however the TVS may allow a few ms of relatively HV to
> >appear on the main buss that can exceed the equipment ratings.
>
> Only if the equipment is not designed to live in the real
> world of airplanes (or any other vehicle with a DC power
> generation system).
Agree but in the real world there is a lot of low cost equipment available
that some of us can afford that may not meet the real world enviroment and
needs some external help.
> >Mostly agree on Z-24, however, protection from pilot is only part of the
> >concern. I really do not like the use of procedures to prevent equipment
> >damage. Throwing the incorrect switch should never cause damage!
>
> It's not a procedure . . . it's a rational/natural mode of
> operating the airplane. One should not apply rapid full
> travel of flight controls above certain published airspeeds . . .
> okay as far as procedures go but I've never had occasion or
> desire to exercise it. By the same token, I cannot recall a
> single time I felt a need to cycle alternator and/or battery
> switches for anything other than troubleshooting on the ground
> or in the normal course of turning things on during preflight
> and turning things off before I park the airplane.
Many pilots are not as well disciplined and its easy to hit the incorrect
switch in a panic or simply by accident. So I disagree, regardless of the
word used improper or accidental switch actuation should never result in
damage. Guards and or locking levers prevent accidental actuation but does
not prevent bad thinking by the pilot who believes that turning off the
alternator with the engine running is OK.
>
> Even then the alternator always goes off first and does NOT have
> an internal regulator. You can take ANY certified single with
> the infamous split rocker master switch and punch the alternator
> and battery off simultaneously by hitting both sides of the
> switch. This simultaneously disconnects the battery AND the
> alternator field . . . the mechanically linked nature
> of the split-rocker COMBINED with the fact that all spam-cans
> have externally regulated alternators makes this action a non-
> event with respect to battery dump.
Again disagree with ALL. I fly a friends spam can and he lost the external
regulator when electrical smoke appeared in the cockpit and he hit the dual
off rocker. True no avionics were damaged but the alternator regulator was
fried and this was a factory supplied regulator.
In the above case I believe the battery contactor slow opening time of
several MS allowed the alternator to shut\down with no "dump".
> >I am addressing a different case. First, not everyone has your
progressive
> >switches;
All of us do not like toggle switches etc and while its fine to suggest you
use what you have designed in its also worth considering others need to be
able to provide the same safety with "normal" rockers or other styles that
are simple not available in sequential design.
> Can't help it if the reasoning behind the use of
> progressive master switches is misunderstood or ignored.
I suspect there are many who do not fully understand. Perhaps I missed it
but I see no note in appendix Z (just downloaded) describing the requirement
for the sequential switch.
> The split rocker was crafted to address these issues
> 45 years ago . . . and aside from the fact that it
> mounts in a square cornered hole and looks nothing
> like the other switches in the panel, there's nothing
> "wrong" with the split rocker. It's made by Carling
> and has the same guts behind the panel as the 2-10
> toggle switch. The spirit and intent of this switch
> has stood the test of time quite well even if the
> switch itself has been root cause of many unnecessary
> replacements for alternators and regulators in spam-cans.
> The Z-figures have shown either simultaneous or progressive
> disconnection of alternator/battery since day-one. If
> someone chooses to wire their airplane like a Bonanza,
> well . . .
>
> > and you do not seem to address contactor failure. (however
> >unlikely its not zero).
>
> Contactor failure, particularly contactor failure while the
> battery presents a substantial portion of the total alternator
> load is very rare.
>
>
> >Failure of one device should never cause additional failures. I suggest
that
> >a battery contactor failure should not result in a load dump where the
> >alternator is still connected to the main bus. Regardless of the
potential
> >damage of the alternator regulator the main bus gets the impact of the
load
> >dump and prtection needs to be added in my opinion.
>
> The combination of DO-160 qualification and designing electrical
> systems constrained to Mil-STD-704 has a pretty good track record
> for covering all the bases . . . including battery-dump. If one
> chooses to install accessories which are less robust, then there
> are certainly new issues to be considered.
>
>
> >My testing to date has shown to me that the remaining issue is the peak
> >voltage and duration during the TVS protected load dump VS the ability of
> >the equipment to tolerate that transient.
>
> Can you share a repeatable experiments for the tests and the
> data derived therefrom? We've been hashing this topic for
> several weeks now but I've yet to see hard data by which
> one can make rational recommendations for either part
> selection or places where it's a good thing to include
> as part of the system design.
Addressed earlier. I will post what I can when I have accurate info VS a
simple test setup where repeatability and accurate measurements are not
made. I am just looking for rough info at present and what may work as a
clamp.
> Everyone is free to stack as many "firewalls" against the
> extraordinary and unexpected as they wish. I try to avoid
> recommendations for firewalls in favor of designing the risks
> out (which is, in part, what DO-160 is about). I'll be pleased
> to have some real hammer-n-tongs data for color and size of the
> beast. It will be nice if there's a practical, one-part
> solution with sufficient stature to provide a 99% plus
> probability for standing off a battery dump event.
>
>
I think we have such a part today. There is a 500 amp TVS designed
specifically for this subject load dump (mentioned much earlier in ths
thread as I recall). Not stocked, so I went to the 160 amp 5kw part that was
in stock. It seems to work for me and should keep the dump event under
DO-160 testing. However I do have some equipment that appears to be unable
to pass DO-160 and so I am continuing to investigate.
Perhaps my background in space craft is biasing my thinking. There we did
what ever was possible to prevent single point failures regardless of
probability based on real experience that even a 0.0001% probable event can
and did happen.
Perhaps you would like to know that I recommend your "book" etc to other
builders and admonish them to follow the the info 100%. Or ask specific
questions about any deviations (including the use of progressive switches
:-) )
Paul
EAA TC, FA
________________________________________________________________________________
From: | "Troy Scott" <tscott1217(at)bellsouth.net> |
Subject: | ?B lead to contactor or to battery? |
Gentlemen,
I note that all the Z drawings show the alternator B lead connected to a
contactor rather than directly to a battery or hot bus. Is this necessarily
always the case? Is this done to facilitate OV protection? Is this more
appropriate to internally regulated alternators that to externally regulated
alternators?
Regards,
Troy Scott
tscott1217(at)bellsouth.net
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Fw: Transponder arial location |
>
>
>----- Original Message -----
>From: Rick Fogerson
>To: aeroelectric-list(at)matronics.com
>Subject: Transponder arial location
>
>
>Hi Bob,
>I've got a xpdr arial question for you. I have installed that little 3
>inch long arial with a ball (B&C) belly just aft of the firewall between
>the exhaust pipes. The arial would be shielded some in the forward
>direction by the portion of the lower cowl where cooling air exits and the
>exhaust pipes emerge from the engine compartment. That wasn't a problem
>when I was going to install the standard frp cowl but now I thinking of
>trying to build an aluminum cowl. How much of a problem do you think this
>would be?
There's no way to deduced effects of proximity without
going to the antenna range and doing real-time tests
or doing a computerized study with some rather expensive
hardware.
Probability is that complaints from ground controllers
concerning readability of your transponder will be rare
if you position the antenna as you describe.
Bob . . .
________________________________________________________________________________
From: | "Mike Holland" <hollandm(at)pacbell.net> |
Subject: | Re: Battery dumps |
Bob, etal. my main concern isn't pilot error but a crowbar induced disconnect
of my Z24 contactor. I understand that this device has proven reliable but it
is a device and together with the contactor and all the necessary wiring, is
a system with multiple failure modes. Estimating the aggregate improbability
of this would be difficult but I'm sure it isn't zero.
I have two main concerns; avoiding dark and stormy night stories and protecting
expensive gadgets. For those (like me) who have rudimentary electrical understanding,
and given the proven issues around disconnecting alternators in-flight,
why do we provide separate control of alternators in airplanes at all?
Why not do what is done is cars and wire b-leads to the battery though fat in-line
fuses? Any smoke would be confined to the engine compartment and my load
meter would instantly tell me I have dropped one or more alternators and to
start looking for a place to land.
And whether the fried regulator is internal/external would seem to be beside the
point since regulator quality and design is the key, and not where it is physically
located.
As someone still building but trying to follow diligently your excellent advise,
I find all this a bit daunting.
In spite of apprehensions they inspire I appreciate the enlightening discussions.
Eventually they will lead to improved designs. It does concern me that focus
of the discussion appears to be taking us in the direction of greater, not
less, complexity. Isn't there a simpler strategy that would potentially sacrifice
a regulator (internal or external) and protect avionics?
Mike Holland
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>Bob,
>What is your current recommendation for a loadmeter? Searching the
>archives indicates that the loadmeter kits are no longer available. Is
>there another instrument available that can be modified to indicate system
>load rather than the minus -0 -plus ammeter?
>Thanks,
Sure . . . sorta. The generic loadmeter is an instrument that
reads full scale with 50 millivolts impressed across the
terminals and a scale plate that read either 0-100% or
0 to some value commensurate with the size of the shunt.
Exemplar displays can be seen at:
http://www.aeroelectric.com/Pictures/load-ammeter.jpg
In years gone by, analog instruments like those depicted
above were the norm. Many production aircraft like the
Beechjet still have these exact same instruments in the
cockpit overhead as both voltmeters and loadmeters (NOT
expanded scale voltmeters however). There used to be
many fine houses that produced moving coil, pivot and
jewel instruments in all sizes . . . many of them
small enough and rugged enough to be attractive to
the airplane designer.
Nowadays, and in particular in the OBAM aircraft community,
electrical data readouts are more often being supplied
as part of comprehensive instrumentation packages like
Vision-Microsystems in digital or digital/quasi-analog
displays.
We know that inclusion of voltage and/or loads data
on the panel is most useful for diagnostics. In the
thoughtfully designed and maintained electrical system
there is little value in "knowing the numbers" when
it comes to dealing with electrical system adversity
in flight.
I'd be quite comfortable flying an airplane with
a (1) e-bus, (2) battery selected and maintained
so as to support e-bus loads for duration of fuel
aboard and (3) LV warning light such as I've depicted
at:
http://www.aeroelectric.com/Catalog/AEC/9005/9005-701B.pdf
You may be aware of a product I used to offer that
added some diagnostic instrumentation to a low voltage
warning light shown in
http://www.aeroelectric.com/temp/9021704F.pdf and
http://www.aeroelectric.com/temp/loadvolt.jpg
I discontinued that product due to high rate of return
on the custom instrument made for me by Westach. The
majority of their product plays well but I had about
10-15% return on their instruments for various reasons
and experienced what I felt was poor attitude about
making good on their products.
I am currently considering a new product . . . based
on instruments by a very capable, old-line instrument
manufacturer. They're well built, rugged 1.5" square
meters and easily modified to the specific tasks of
loadmeter and expanded scale voltmeters. You can see
the loadmeter prototype at:
http://www.aeroelectric.com/Pictures/Loadmeter_2.jpg
To successfully bring this product to the marketplace,
I need to invest a pretty big chunk of up-front dollars
to acquire several years worth of "stock" instruments
for production and spares.
Given the shift to digital instrumentation -AND-
the reality that putting these instruments on the
panel is a help only to the mechanic and not the
pilot . . . I'm wrestling with the decision to
stock up on raw-material instruments.
I approached Mitchell a few months ago about doing
these instruments but they declined. They may have
the same foreboding about the future of steam gages
on panels and/or it may be that they don't appreciate
the potential for servicing the OBAM aircraft community.
At the moment, it appears that if a reasonably
priced, quality set of instruments are going to
come to the market as either loadmeters, voltmeters
or any other task, I'm going to have to do it.
I expect to make up my mind in the next 30 days
or so.
Irrespective of how all the decisions shake out,
I cannot get excited about putting a -0+ reading
battery-ammeter in an airplane.
Bob . . .
________________________________________________________________________________
Subject: | Dual battery voltage monitoring with alarm |
From: | "Scott, Ian" <ian_scott(at)commander.com> |
this is a marine instrument designed for 3 battery banks, however would seem to
work fine for dual battery installs.
http://www.cruzpro.com/v30.html
Ian
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aeroelectric-list(at)matronics.com
From: | Kevin Horton <khorton01(at)rogers.com> |
Subject: | Dynon Remote Compass mounting? |
I'm pondering the details of how to mount the remote compass sensor
for my Dynon EFIS. I'm leaning towards hanging it from the top of
the F-809 bulkhead on my RV-8, somewhat similar to:
http://home.comcast.net/~jwdanie/Compass/compass.html
But, I'm worried about potential interference from the high voltage
strobe light line that goes from the power supply back to the tail
strobe. I could reroute that guy lower, but it will be a real PITA.
So, I'm wondering how close anyone has run a strobe light cable (the
big grey one that goes from the power supply to the light) to the
EDC-10 remote compass mount. If you've got such a strobe line in the
area of your remote compass sensor, tell me how far away it is, and
whether you can see any effect on heading from it.
My strobe cable would probably be about 8 inches from the compass
sensor if I don't move it. I don't want to move it if I can get away
with it.
Thanks,
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Battery dumps |
>
>Bob, etal. my main concern isn't pilot error but a crowbar induced
>disconnect of my Z24 contactor. I understand that this device has proven
>reliable but it is a device and together with the contactor and all the
>necessary wiring, is a system with multiple failure modes. Estimating the
>aggregate improbability of this would be difficult but I'm sure it isn't zero.
>
>I have two main concerns; avoiding dark and stormy night stories and
>protecting expensive gadgets. For those (like me) who have rudimentary
>electrical understanding, and given the proven issues around disconnecting
>alternators in-flight, why do we provide separate control of alternators
>in airplanes at all?
IF you're wired to include an e-bus and you have ov protection
for the alternator and you plan to maintain a battery such that
it keeps the e-bus alive for duration of fuel aboard, then you
have a failure tolerant system that will deprive you of the
experience of writing a dark-n-stormy night story . . .
Further, unless you're in the habit of flipping the right
switches at the wrong times, you're not at much risk for
an event that causes damage.
>Why not do what is done is cars and wire b-leads to the battery though fat
>in-line fuses? Any smoke would be confined to the engine compartment and
>my load meter would instantly tell me I have dropped one or more
>alternators and to start looking for a place to land.
But when the smoke is coming from some place other than alternator wiring,
how do you make the system totally cold? Looking for a place to land in
response to smoke is to capitulate in the face of and electrical
EMERGENCY . . .
something I try to avoid by thoughtful design and maintenance.
>And whether the fried regulator is internal/external would seem to be
>beside the point since regulator quality and design is the key, and not
>where it is physically located.
>
>As someone still building but trying to follow diligently your excellent
>advise, I find all this a bit daunting.
>
>In spite of apprehensions they inspire I appreciate the enlightening
>discussions. Eventually they will lead to improved designs. It does
>concern me that focus of the discussion appears to be taking us in the
>direction of greater, not less, complexity. Isn't there a simpler
>strategy that would potentially sacrifice a regulator (internal or
>external) and protect avionics?
That's essentially what Z-24 does right now. It unhooks
the runaway alternator to save the system. It seems that
some folks have experienced damage to what WAS a working
alternator by turning the alternator off while it was
loaded.
If you have an externally regulated alternator, 99.99% of this
discussion doesn't apply. The 0.01% that does apply concerns the
loss of battery connection on a system with EITHER internally
OR externally regulated alternators while the alternator is
heavily loaded by battery-recharge current. This is so rare
an event that the A36 P.O.H. (this airplane has totally
independent battery and alternator switches) makes no special
note of sequence of switch operation. In fact, it says
"BATTERY and ALTERNATOR switches - OFF". I suppose if I turn
the battery off first, I have exposed the airplane to a
potential battery-dump event. It wouldn't be difficult
to deliberately generate such an event in the A-36. However,
I have to go out of my way to make it happen and
it doesn't happen in the normal course of operating the
airplane PER the P.O.H.
Don't worry about any of the drum-beating and swinging
of swords for the moment. It's a certainty that when
the investigation is complete and the numbers are known,
there WILL be a simple and effective lotion for
soothing all concerns . . . while making sure that you
never experience an electrical emergency.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: B-lead to contactor or to battery? |
>
>
>Gentlemen,
>
>I note that all the Z drawings show the alternator B lead connected to a
>contactor rather than directly to a battery or hot bus. Is this necessarily
>always the case? Is this done to facilitate OV protection? Is this more
>appropriate to internally regulated alternators that to externally regulated
>alternators?
Has nothing to do with style of alternator. The goal is to tie
the b-lead of an alternator to the (+) post of the battery
through the shortest practical lengths of FAT wire. Depending
on how things are situated in your airplane, it may make more
sense to locate your b-lead fuse at the battery contactor instead
of the starter contactor. This is a noise and radiated magnetics
issue and applies to all alternators, internally or externally
regulated.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Battery dumps |
>
> > Many more radios have been smoked
> > for lack of ov protection than for any other reason. Experience
> > indicates (and DO-160 infers) that once this dragon is adequately
> > chained down, probability of letting lots of smoke out of your
> > radios is very low.
>
>I agree but many of us have older equipment that may not have the type of OV
>protection (per DO -160) to withstand a large "dump" where the voltage
>'seems' to get well over 40 V with a simple 5kw 18v device and a 40 amp
>dump. I have not fully instrumented it as yet.
More that 20 years old? The DO-160 recommendations for robust
accessory design have been around for over 30 years.
>Limiting the selection of equipment to certified to DO-160 is not affordable
>in many cases.
>
>I only have the materials and time to test my own alternator etc and do not
>have a ND internal W/WO external alternator. Thus you may get very
>different results. Sorry but every alternator is likely to be somewhat
>different.
>
>However, if you have a load bank that can handle 14V at 40 amps and use a
>contactor to drop the load you can see what the "dump" is.
I plan to to do that. Do you have numbers to share with us from
tests you've done?
>I have had no damage with the 5kw 18v device I am using in my setup but
>another poster has had failures perhaps only due to the test setup. I am not
>placing the TVS at the alternator but several feet away on the power bus
>distribution and as such have some series resistance external to the
>alternator.
Any resistance will be measured in milliohms . . . given the
self limiting magnitude of current source at or below the
limits of the alternator, I doubt that any series resistance
on this order of magnitude is significant. I suspect that
George exceeded the total energy limits for the device which
is going to be more a function of duration of the dump event
as opposed to large currents.
>Nor do I have the time (or interest) to try to see if all my equipment will
>withstand the resulting OV on the bus. My intent is to clamp the OV at its
>source and or prevent the dump from happening in the first place.
>
>I think we agree that if the battery is never taken off line while being
>charged, there will be no dump. Other than contactor failure your designs
>prevent that IF fully followed. The problem is where a builder fails to see
>the reason for your design detail and changes it.
Kind of, but the A-36 Bonanza has completely separate
alternator and battery switches and the P.O.H. makes no
mention of a need to "properly" sequence switches. If
you operate them like the P.O.H. says, there's no
battery-dump event even when the battery switch is
turned off first.
> >
> > Even then the alternator always goes off first and does NOT have
> > an internal regulator. You can take ANY certified single with
> > the infamous split rocker master switch and punch the alternator
> > and battery off simultaneously by hitting both sides of the
> > switch. This simultaneously disconnects the battery AND the
> > alternator field . . . the mechanically linked nature
> > of the split-rocker COMBINED with the fact that all spam-cans
> > have externally regulated alternators makes this action a non-
> > event with respect to battery dump.
>
>Again disagree with ALL. I fly a friends spam can and he lost the external
>regulator when electrical smoke appeared in the cockpit and he hit the dual
>off rocker. True no avionics were damaged but the alternator regulator was
>fried and this was a factory supplied regulator.
>
>In the above case I believe the battery contactor slow opening time of
>several MS allowed the alternator to shut\down with no "dump".
What's the foundation for that supposition? Where did the smoke
come from? What was the magnitude of current flow into the
battery at the time? How do you know that the right conditions
existed at the time to precipitate a battery-dump event that was
held a bay only because of some contactor drop-out delay?
It's a hypothesis I have difficulty supporting. If the smoke
came from the regulator, this may well have been a simple case
of gross failure within the regulator that prompted the pilot
to take the action he did. If accompanied by an OV event, his
swift action may have been hundreds of milliseconds late . . .
the OV protection system may have already shut down the
alternator.
Like the "Sparks in the Dark" story in chapter 17, there
is a LOT of data missing for understanding root cause
and magnitude/sequence of events.
> > >I am addressing a different case. First, not everyone has your
>progressive
> > >switches;
>
>All of us do not like toggle switches etc and while its fine to suggest you
>use what you have designed in its also worth considering others need to be
>able to provide the same safety with "normal" rockers or other styles that
>are simple not available in sequential design.
Progressives are available in rockers too and certainly two-pole
switches are available. Figure Z-12 shows both poles of the
non-progressive DC MASTER switch used to shut down battery and
alternator simultaneously.
> > Can't help it if the reasoning behind the use of
> > progressive master switches is misunderstood or ignored.
>
>I suspect there are many who do not fully understand. Perhaps I missed it
>but I see no note in appendix Z (just downloaded) describing the requirement
>for the sequential switch.
The 'Connection in not intended to levy REQUIREMENTS upon anyone.
I have added an opening paragraph to Revision 11 Z-drawings
to caution folks that the drawings have features which may
not be readily apparent to the builder but important
to achieve a failure tolerant, trouble free design. Before ANY changes
are implemented, they should get on the AeroElectric-List and
tell us how the as-published drawings fall short of some
perceived goal. There will also be a new note specific to the
DC power master switch that addresses the value in NOT allowing
the alternator to remain on line after the battery is shut
off.
>I think we have such a part today. There is a 500 amp TVS designed
>specifically for this subject load dump (mentioned much earlier in ths
>thread as I recall). Not stocked, so I went to the 160 amp 5kw part that was
>in stock. It seems to work for me and should keep the dump event under
>DO-160 testing. However I do have some equipment that appears to be unable
>to pass DO-160 and so I am continuing to investigate.
Can you share a part number with us?
>Perhaps my background in space craft is biasing my thinking. There we did
>what ever was possible to prevent single point failures regardless of
>probability based on real experience that even a 0.0001% probable event can
>and did happen.
>
>Perhaps you would like to know that I recommend your "book" etc to other
>builders and admonish them to follow the the info 100%. Or ask specific
>questions about any deviations (including the use of progressive switches
>:-)
I do appreciate your vote of confidence my friend. I will
do my best to be worthy of it.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Dynon Remote Compass mounting? |
>
>I'm pondering the details of how to mount the remote compass sensor
>for my Dynon EFIS. I'm leaning towards hanging it from the top of
>the F-809 bulkhead on my RV-8, somewhat similar to:
>
>http://home.comcast.net/~jwdanie/Compass/compass.html
>
>But, I'm worried about potential interference from the high voltage
>strobe light line that goes from the power supply back to the tail
>strobe. I could reroute that guy lower, but it will be a real PITA.
>So, I'm wondering how close anyone has run a strobe light cable (the
>big grey one that goes from the power supply to the light) to the
>EDC-10 remote compass mount. If you've got such a strobe line in the
>area of your remote compass sensor, tell me how far away it is, and
>whether you can see any effect on heading from it.
>
>My strobe cable would probably be about 8 inches from the compass
>sensor if I don't move it. I don't want to move it if I can get away
>with it.
There should be NO magnetic field radiated from your
strobe lines. Don't worry about them affecting your
compass sensor.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> alarm |
Subject: | Re: Dual battery voltage monitoring with |
alarm
alarm
>
>
>
>this is a marine instrument designed for 3 battery banks, however would
>seem to work fine for dual battery installs.
>
>http://www.cruzpro.com/v30.html
>
>Ian
Cute. I'm mystified as to why it's so BIG . . . 4" deep
over all. Found them offered for sale at this
site:
http://www.emarineinc.com/products/monitors/v30.html
for $129. Seems a reasonable price for the
capability. One could monitor the main bus
and two batteries with this critter. You might
want to power it trough a panel mounted switch.
The published 0.017A draw would run your battery
down in about 6 weeks.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Help with Diagnosis |
>
>
>My already flying when I bought it RV 6 A has a B&C alternator and a
>LR3C-14 voltage regulator. The builder used a 10 amp fuse in the Field
>line.
This is contrary to recommended installation. Suggest you consider
rewiring to include the suggested 5A breaker per installation
instructions.
> Some months ago when I had a low battery, an attempt to jump the
>battery got a lot of sparks in the vicinity of the LR3C-14.
I am always concerned about reports of "sparks" wherein their
source is not researched and identified. See chapter 17 of
the 'Connection for another sparks-outta-nowhere story.
> About 3 flying
>hours later the fuse blew and we got home on the battery. Today the fuse
>blew again. We landed and replaced the fuse. Everything seemed OK during
>taxi and run-up, but the fuse blew again shortly after take-off. Got home
>on battery again. Since my home airport is in the DC ADIZ this needs to be
>fixed properly. Where do I start to look? A short in the field wire is
>the first place, what next? Thanks in advance for the help.
Do you have any idea where the sparks came from? How
did you observe them? You either have a wiring problem
or the crowbar ov system in the LR3 is being tripped.
How old is the LR-3? There was a mod to the design to
fix an nuisance tripping problem with the OV system but
since your problems seem to post-date another issue
(sparks) with un-explained origin, the LR-3 may be fine
and only the wiring needs investigation. If it were my
airplane, I'd install the recommended 5A breaker, install
ALL new wiring in the field supply circuit and see if
the problem goes away.
If it's still tripping the breaker, we'll need to dig
further.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>In a message dated 2/27/2004 7:26:51 PM Mountain Standard Time,
>Bobdeva(at)aol.com writes:
>
> >
> > Anyone have a source for a good alternator? (Other than B&C.) I want a
> good
> > alternator that is NOT internally regulated. Price is not important, you
> > usually
> > get what you pay for. 40 or 60 amp. for Lyc. O320.
> > Thank you,
> > Bob Devaney
Bob, virtually ALL modern alternators are supplied
from the factory with built in regulators. Your
best bet is to get a junk-yard Nipon-Denso and modify
it yourself or have it modified. Is there a local
alternator shop that could help you?
Bob . . .
________________________________________________________________________________
From: | "Gilles St-Pierre" <ranchlaseigneurie(at)hotmail.com> |
Subject: | Weird LED fuse behavior |
most of the time this has something to do with a bad ground .or a loose
connection
bsl aviation
gilles
elite 717
>From: "John Slade" <sladerj(at)bellsouth.net>
>Reply-To: aeroelectric-list(at)matronics.com
>To:
>Subject: AeroElectric-List: Weird LED fuse behavior
>Date: Sat, 28 Feb 2004 22:12:12 -0500
>
>
>
>Here's a strange one for someone....
>
>I have those fuses with an LED that lights up when they blow.
>
>When running my engine for the first time I notice that the LED for the
>fuel
>injection computer (on the essential buss) is glowing, and that the glow
>changes in intensity with rpm - i.e. I can light it up more by pushing the
>throttle. On shut down I find that the fuse is not blown. I'm not seeing
>any
>charge on the buss from the alternator, and I'm wondering if this may have
>something to do with it. Perhaps the alternator solenoid is open, but I
>can't see how that would affect voltage or cause some sort of reverse flow
>effect.
>
>Any ideas anyone?
>John Slade
>Cozy IV turbo rotary - making noise
>
>
________________________________________________________________________________
From: | "Jim Jewell" <jjewell(at)telus.net> |
Subject: | Re: Battery dumps |
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Re: Battery dumps
>
> >
> >Bob, etal. my main concern isn't pilot error but a crowbar induced
> >disconnect of my Z24 contactor. I understand that this device has proven
> >reliable but it is a device and together with the contactor and all the
> >necessary wiring, is a system with multiple failure modes. Estimating
the
> >aggregate improbability of this would be difficult but I'm sure it isn't
zero.
> >
> >I have two main concerns; avoiding dark and stormy night stories and
> >protecting expensive gadgets. For those (like me) who have rudimentary
> >electrical understanding, and given the proven issues around
disconnecting
> >alternators in-flight, why do we provide separate control of alternators
> >in airplanes at all?
>
> IF you're wired to include an e-bus and you have ov protection
> for the alternator and you plan to maintain a battery such that
> it keeps the e-bus alive for duration of fuel aboard, then you
> have a failure tolerant system that will deprive you of the
> experience of writing a dark-n-stormy night story . . .
>
> Further, unless you're in the habit of flipping the right
> switches at the wrong times, you're not at much risk for
> an event that causes damage.
>
>
> >Why not do what is done is cars and wire b-leads to the battery though
fat
> >in-line fuses? Any smoke would be confined to the engine compartment and
> >my load meter would instantly tell me I have dropped one or more
> >alternators and to start looking for a place to land.
>
> But when the smoke is coming from some place other than alternator
wiring,
> how do you make the system totally cold? Looking for a place to land
in
> response to smoke is to capitulate in the face of and electrical
> EMERGENCY . . .
> something I try to avoid by thoughtful design and maintenance.
>
>
> >And whether the fried regulator is internal/external would seem to be
> >beside the point since regulator quality and design is the key, and not
> >where it is physically located.
> >
> >As someone still building but trying to follow diligently your excellent
> >advise, I find all this a bit daunting.
> >
> >In spite of apprehensions they inspire I appreciate the enlightening
> >discussions. Eventually they will lead to improved designs. It does
> >concern me that focus of the discussion appears to be taking us in the
> >direction of greater, not less, complexity. Isn't there a simpler
> >strategy that would potentially sacrifice a regulator (internal or
> >external) and protect avionics?
>
> That's essentially what Z-24 does right now. It unhooks
> the runaway alternator to save the system. It seems that
> some folks have experienced damage to what WAS a working
> alternator by turning the alternator off while it was
> loaded.
>
> If you have an externally regulated alternator, 99.99% of this
> discussion doesn't apply. The 0.01% that does apply concerns the
> loss of battery connection on a system with EITHER internally
> OR externally regulated alternators while the alternator is
> heavily loaded by battery-recharge current. This is so rare
> an event that the A36 P.O.H. (this airplane has totally
> independent battery and alternator switches) makes no special
> note of sequence of switch operation. In fact, it says
> "BATTERY and ALTERNATOR switches - OFF". I suppose if I turn
> the battery off first, I have exposed the airplane to a
> potential battery-dump event. It wouldn't be difficult
> to deliberately generate such an event in the A-36. However,
> I have to go out of my way to make it happen and
> it doesn't happen in the normal course of operating the
> airplane PER the P.O.H.
>
> Don't worry about any of the drum-beating and swinging
> of swords for the moment. It's a certainty that when
> the investigation is complete and the numbers are known,
> there WILL be a simple and effective lotion for
> soothing all concerns . . . while making sure that you
> never experience an electrical emergency.
>
> Bob . . .
>
>
________________________________________________________________________________
From: | "David Carter" <dcarter(at)datarecall.net> |
Subject: | Re: Battery dumps |
For Bob N. & Paul Messinger, especially, and Eric Jones: I've studied the
sharing of ideas and views on this Battery Dump thing. I believe Mike
Holland's e-mail below (part), which mentions "big in-line fuse" type
device. Fuses & CB all have a "time rating". I believe a big B-Lead fuse
or limiter would be a "slow blow" item.
- I think the discussion should be momentarily limited so we (you!)
focus on the 1 thing that I believe has not, so far, been isolated out and
clearly addressed/responded to: "Time or Duration of the Event before it is
'killed'. "
- Seems to me, if we set aside the reasonable assessment of risk that Bob
has given, and we do that so we can address the "root technical issue", I
believe that issue to be this one of "time".
-- Can the OverVoltageProtection module & associated contactor (OVP
system) open fast enough to prevent the Dump's hi-voltage from getting onto
"main bus" for a long enough time to damage non-DO-160 gadgets?
-- To repeat & expand: If ANYTHING or WHATEVER causes a
"significant" Battery Dump event (i.e., a non-PM alternator producing high
enough volts and current to damage non-DO-160 gadgets if left unmitigated),
then will the OVP system (contactor) open fast enough to limit the time to
____ ms? __ ms being short enough so that there will be no damage caused
by the HI VOLTAGE that WILL go downstream, past the OVP contactor, and into
the "electrical distribution bus" and (potentially finicky) equipment
connected thereto?
David
----- Original Message -----
From: "Mike Holland" <hollandm(at)pacbell.net>
Subject: AeroElectric-List: Re: Battery dumps
>
> Bob, etal. my main concern isn't pilot error but a crowbar induced
disconnect of my Z24 contactor. I understand that this device has proven
reliable but it is a device and together with the contactor and all the nece
ssary wiring, is a system with multiple failure modes. Estimating the
aggregate improbability of this would be difficult but I'm sure it isn't
zero.
>
> I have two main concerns; avoiding dark and stormy night stories and
protecting expensive gadgets. For those (like me) who have rudimentary
electrical understanding, and given the proven issues around disconnecting
alternators in-flight, why do we provide separate control of alternators in
airplanes at all?
>
> Why not do what is done is cars and wire b-leads to the battery though fat
in-line fuses? Any smoke would be confined to the engine compartment and my
load meter would instantly tell me I have dropped one or more alternators
and to start looking for a place to land.
>
> And whether the fried regulator is internal/external would seem to be
beside the point since regulator quality and design is the key, and not
where it is physically located.
>
> As someone still building but trying to follow diligently your excellent
advise, I find all this a bit daunting.
>
> In spite of apprehensions they inspire I appreciate the enlightening
discussions. Eventually they will lead to improved designs. It does
concern me that focus of the discussion appears to be taking us in the
direction of greater, not less, complexity. Isn't there a simpler strategy
that would potentially sacrifice a regulator (internal or external) and
protect avionics?
>
>
> Mike Holland
>
>
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
Subject: | Re: Battery dumps |
>
>
> More that 20 years old? The DO-160 recommendations for robust
> accessory design have been around for over 30 years.
Recomendations are not requirements and even today, stuff is designed and
sold with no specific verified compliance with DO-160.
> >However, if you have a load bank that can handle 14V at 40 amps and use a
> >contactor to drop the load you can see what the "dump" is.
>
> I plan to to do that. Do you have numbers to share with us from
> tests you've done?
Eventually but what I have so far is not properly instrumented and based on
your past comments about specifics its too soon to provide exact data.
I will post when I have exact data but its will require a better setup for a
chance of repeatable duplication by others.
> >I have had no damage with the 5kw 18v device I am using in my setup but
> >another poster has had failures perhaps only due to the test setup. I am
not
> >placing the TVS at the alternator but several feet away on the power bus
> >distribution and as such have some series resistance external to the
> >alternator.
>
> Any resistance will be measured in milliohms . . . given the
> self limiting magnitude of current source at or below the
> limits of the alternator, I doubt that any series resistance
> on this order of magnitude is significant. I suspect that
> George exceeded the total energy limits for the device which
> is going to be more a function of duration of the dump event
> as opposed to large currents.
Even a small resistance in series with the TVS reduces the peak voltage as
the TVS has a vary low resistance also. I agree that the peak current is
limited to perhaps 150% of the alternator rated output or lower and not the
huge currents seen in some ref material. Also we are not discussing a
shorted output but a alternative path for the excess current for say 40 amps
and the TVS supplies that path at a starting V of around 21V based on the
18V rated unit. The peak voltage then increases from 21V based on the
internal resistance of the TVS. BTW I tested over 100 18V TVS units in both
1.5KW and 5KW ratings and the 21V point was in the range of 20.5V - 21.3V.
Perhaps a 16V TVS would be better but 5KW @16V was not easily available.
> Kind of, but the A-36 Bonanza has completely separate
> alternator and battery switches and the P.O.H. makes no
> mention of a need to "properly" sequence switches. If
> you operate them like the P.O.H. says, there's no
> battery-dump event even when the battery switch is
> turned off first.
Well the S35 I had specifically said the excess fuel was routed to the
selected tank both in writing and on the diagram. NOT so its always routed
to the left tank. Thus with full tanks there was a unmentioned REQUIREMENT
to use the left tank first.
As for no dump how do you know for sure?? with the battery being charged at
a hi rate I would expect some spike with a minimal electrical system load.
After all, load dump is known characteristic of alternators that are
suddenly unloaded regardless of how fast the regulator is. Fast regulators
simply reduce the duration of the event not prevent it.
> >Again disagree with ALL. I fly a friends spam can and he lost the
external
> >regulator when electrical smoke appeared in the cockpit and he hit the
dual
> >off rocker. True no avionics were damaged but the alternator regulator
was
> >fried and this was a factory supplied regulator.
> >
> >In the above case I believe the battery contactor slow opening time of
> >several MS allowed the alternator to shut/down with no "dump".
>
> What's the foundation for that supposition? Where did the smoke
> come from? What was the magnitude of current flow into the
> battery at the time? How do you know that the right conditions
> existed at the time to precipitate a battery-dump event that was
> held a bay only because of some contactor drop-out delay?
I know the pilot and I know the results of the failure investigation and
sorry but the regulator failed as the direct result of opening the
battery/bus loads. The smoke was from a radio.
I suppose its possible the regulator decided to fail at that precise time
but that is unlikely and as there was a sudden complete load load loss there
was a load dump and the only question was did the reg fail from "tired" or
from the load dump.
> Like the "Sparks in the Dark" story in chapter 17, there
> is a LOT of data missing for understanding root cause
> and magnitude/sequence of events.
Frankly I see no reason to spend lots of time trying to supply details as
you seem to have already made up your mind. The events that need to take
place for a load dump are well understood. He had such a case, end of
discussion.
> >I think we have such a part today. There is a 500 amp TVS designed
> >specifically for this subject load dump (mentioned much earlier in ths
> >thread as I recall). Not stocked, so I went to the 160 amp 5kw part that
was
> >in stock. It seems to work for me and should keep the dump event under
> >DO-160 testing. However I do have some equipment that appears to be
unable
> >to pass DO-160 and so I am continuing to investigate.
>
> Can you share a part number with us?
I will look up both part numbers.
Can you tell me the specific details of the OV transient test specified in
DO -160 like rise time, peak V and fall time as well as duration. I have no
free access to the subject document and knowing thst info it would help in
determining if the TVS fix was adequate.
I also am replying to another post on this subject that is of interest to
all of us.
Paul
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
Subject: | Re: Battery dumps |
Excellent point. Perhaps 99.99% of those on the list feel like your comments
and could care less about the finer points etc.
more embedded comments
>
> For Bob N. & Paul Messinger, especially, and Eric Jones:
> -- Can the OverVoltageProtection module & associated contactor
(OVP
> system) open fast enough to prevent the Dump's hi-voltage from getting
onto
> "main bus" for a long enough time to damage non-DO-160 gadgets?
ANY voltage over 20V for a TBD time can be a potential problem (at least
with some gadgets) and the issue is what is TBD. A power contactor can take
several MS to open and that time is increased a little by the diode we
install across the contacts. Further the OVP module has a built in time
delay to trip as its intended to detect failure to regulate, not spikes.
As you point out one key is the time to open. It would appear (to me) that
time could be as long as 5 ms. Some contactors are faster to open than
others and we have another variable to consider. Another question is what is
the V spike during this time and will this damage equipment.
I have asked Bob for the details of the "test" spike that DO-160 requires
equipment to pass. We must first be sure that any load dump solution is
inside that test spike. The final question is what about the other non
complying "gadgets" and that is an individual question as there are so many
variables.
I have what seems to work for me nut as you have read its not fully tested
as a proper test requires (lots of setup here) and that is not simple for me
as its dealing with huge (to me) currents. I do have the equipment to
properly monitor and record the event. What is a quick and dirty test that
convinces me is no where enough for the rest of the world including Bob. ;-)
In any event I am working on getting info that can be repeated and should
solve the problem with a simple fix.
The 500Amp TVS I have mentioned is specifically designed for load dump
protection and is designed to fail short if overloaded. This is not
necessarly a solution for us as the clamp voltage may be too high for us as
its inteneded for auto use.
I have started on getting samples but this can take a lot of time based on
past experience with that mfgr.
Paul
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Battery dumps |
>
>
>For Bob N. & Paul Messinger, especially, and Eric Jones: I've studied the
>sharing of ideas and views on this Battery Dump thing. I believe Mike
>Holland's e-mail below (part), which mentions "big in-line fuse" type
>device. Fuses & CB all have a "time rating". I believe a big B-Lead fuse
>or limiter would be a "slow blow" item.
Correct. Like all "fuses" and breakers, these devices are for one
purpose only, protect wires and the rest of the system from the effects
from hard faults (very high current up to dead shorts). These devices
never figure into the OV (failed regulator) or battery-dump (transient
surges) event. Many folks confuse the role of the 5A alternator
control breaker as an integral part of the OV protection scheme when
teamed with a crowbar OV module. Yes, the breaker does open in
response to a high current DELIBERATELY GENERATED BY THE CROWBAR
OV MODULE. The breaker is not providing a first order response to
the ov condition, only a second order response to the protection
module which is the actual OV event sensor. If no first order OV
protection is provided (crowbar OV module or OV relay) then a
failed regulator can precipitate a series of very expensive events
without opening a single breaker or fuse.
> - I think the discussion should be momentarily limited so we (you!)
>focus on the 1 thing that I believe has not, so far, been isolated out and
>clearly addressed/responded to: "Time or Duration of the Event before it is
>'killed'. "
Correct.
> - Seems to me, if we set aside the reasonable assessment of risk that Bob
>has given, and we do that so we can address the "root technical issue", I
>believe that issue to be this one of "time".
and energy to be contained during that time.
> -- Can the OverVoltageProtection module & associated contactor (OVP
>system) open fast enough to prevent the Dump's hi-voltage from getting onto
>"main bus" for a long enough time to damage non-DO-160 gadgets?
No. OV protection is deliberately delayed in it's response time
to reduce the likelihood of nuisance trips. Further, if one subscribes
to the traditional notions of delay time as defined by Mil-STD-704
(and subscribed to by the certified aviation community), then delay
times are inversely related to the magnitude of the OV event. I.e.,
the higher the voltage, the shorter the time. The acceptance test
for many OV protection devices calls for stepping bus voltage from
14 to 20 volts and observing the trip time to be 30-50 milliseconds.
An 80 volt step will trip it in 3-5 milliseconds.
> -- To repeat & expand: If ANYTHING or WHATEVER causes a
>"significant" Battery Dump event (i.e., a non-PM alternator producing high
>enough volts and current to damage non-DO-160 gadgets if left unmitigated),
>then will the OVP system (contactor) open fast enough to limit the time to
>____ ms? __ ms being short enough so that there will be no damage caused
>by the HI VOLTAGE that WILL go downstream, past the OVP contactor, and into
>the "electrical distribution bus" and (potentially finicky) equipment
>connected thereto?
Excellent questions sir that require illustrative answers. DO-160
suggests that any device intended for installation on 14V aircraft
be capable of withstanding 20 volts for 1 second and 30 volts for
100 milliseconds for level B certification (level Z calls for 40
surge for 100 milliseconds). I've been building black boxes for
aircraft and testing to level Z for over 25 years. As I've mentioned
before, it's not difficult and it's hard for me to understand
why folks who sell to the OBAM aircraft community don't rise to
the occasion and make lots of folks worries go away.
The 20/1.0 and 30/0.1 surge envelopes are based on a runaway
alternator/generator event. The times and voltages are
suggested to have some headroom between what the accessory
can withstand and how fast we can expect a nuisance-trip-free
OV protection system to react to the failure and bring the
runaway alternator/generator to heal.
The battery-dump event is a completely separate beast.
On a 14V aircraft, there is a potential for higher voltages
but the timing is (I belive) much shorter. Further, while
a runaway alternator event is capable of delivering hundreds
of watt-seconds of energy to the system, I belive the
battery-dump event is limited to a small fraction of that.
In answer to your last question, a battery-dump event
triggered by actual disconnection of the battery will
have a magnitude and duration of transient that is
a function of alternator RPM, proportions and magnitude
of loads represented by accessories and the battery.
For example, a battery disconnect with a full or nearly
full charge battery is a non-event irrespective of
system accessory loads. A battery disconnect event with
system accessory loads taking a major portion of the
alternator's output capacity is also a non-event
irrespective of battery state of charge.
Given all these independent variables, I think it's
easy to visualize why risks to life and hardware from
the battery-dump event are so low . . . especially if
builders of aircraft accessories have an ounce of
knowledge/integrity with respect to DO-160 recommended
robustness.
The more specific case of battery/load-dump involves
opening the b-lead disconnect contactor in response
to an OV event (in which case the alternator's regulator
was already toast) or pilot operation of the alternator
control switch. Here, the alternator doesn't know
and doesn't care what proportion of total load
is represented by battery and system accessories.
Further, only the alternator's regulator is at-risk.
Here the scenario is more problematical. Total load
on alternator goes to zero. The alternator may or
may not run indefinitely as a self excited, yet unloaded
source of power. Opening the alternator b-lead
contactor doesn't actually shut the alternator off,
it simply unhooks it from the airplane.
If the b-lead contactor opens due to a real
OV event, disconnection will save the system but
the alternator will continue to produce whatever
energy it is capable of. In this case, any TVS
we put across the output to stand-off a battery
dump event is toast. If it shorts and doesn't
self-destruct (some plastic devices literally
explode leaving two lead wires dangling in the
breeze) then the dead short will stall the alternator
and effect a complete shutdown. If the TVS comes
apart, then the alternator may well continue to
run at max output until either the field winding
burns up or diodes short.
If the b-lead contactor is purposefully opened
and the regulator is okay, then independent
variables of RPM and total load stack up to
size both magnitude and duration of the surge. If
the surge is below levels hazardous to the
regulator, it's all over in a tens of milliseconds
and the alternator drops to a self excited mode
of reasonably stable but certainly non-hazardous
operation. Adding a TVS device is probably
the mitigating device to protect the regulator
(an perhaps other system accessories in case of
a battery disconnect cited above) . . . but I
hope it's clear that it's not the holy grail
of protection nor is the grail itself invulnerable.
Last, I think we're going to find that there
are NO TVS devices that will limit stresses to
less than 20v during a battery disconnect event
where system loads are light and battery recharge
loads are high. If folks like Microair with their
published 16v limits are accurate and serious about
this limit, then there is NOTHING short of designing
an input power conditioner that will protect this
radio . . . something they should have put in from
the get-go. See where that 20 volts for one second
number came from?
The short answer to your question is, "no, the
OV protection system's duties and capabilities
do not include protection from the battery-dump
event."
In the interest of clarity of speech, I'll suggest
we use "surge" to describe the battery-dump event.
It's an event bounded by perhaps 100 volts and
100 milliseconds and 100 watt seconds. The "spikes"
produced by contactor and relay coils are bounded
by 1000v, 10 milliseconds and tens of MILLIJOULES
of energy. Very different critters.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: batteries and diode isolation |
>
>Bob, I'd like to understand better why you prefer to use contactors and
>separate buses for 2 batteries, as opposed to diodes and allowing both
>batteries to feed the same bus.
>
>I recently saw an elegant circuit that does this and allows both batteries
>to be charged by the alternator at the same time.
>
>I have read your treatise on battery isolation so many times I can almost
>quote it, but nowhere do you address the possibility that there might be a
>way of allowing 3 electrical sources to "automatically" determine - using
>diodes - which ones will be feeding the loads. It would seem to require so
>much less pilot workload than flipping switches to cut in and out
>batteries, requires less current than supporting 2 battery contactors, and
>would still elegantly support the concept of annual battery rotation, low
>voltage notification, etc.
>
>Diodes are available now with voltage drop of 0.3V and with max forward
>currents of 240A, so the diodes themselves would not seem to be an issue.
Without seeing a schematic of what you propose, it's difficult
to assess characteristics of the system. How would you incorporate
diodes into a system that (1) provides pilot-operated disconnection
of batteries and (2) parallels batteries as needed for cranking?
It's not that diodes are evil devices, for all the benefits they
bring, they do not substitute for some system requirements
include the items cited above. Once you add switches or contactors
to orchestrate these features, the diodes are not especially
helpful and certainly not necessary.
We use lots of diodes in the power distribution of biz-jets
and the like . . . but they're always used like the e-bus
normal feed path diode - to provide no-moving parts isolation between
sections of the distribution system where cranking and
disconnection issues are not part of the design.
Bob . . .
________________________________________________________________________________
From: | "Dale Martin" <niceez(at)cableone.net> |
Subject: | Re: Help with Diagnosis |
I have had this similar thing happen to me (28v system).
However, if I turned on the electric heater (draws either 20 or 35 amps),
the breaker would never pop. And it never popped at low RPM. The B&C
engineer and I think its a ground loop problem or a possible short. The
FIX -- I removed my whole electrical system for an update and what little
14 volt items were in the system are ALL removed. So, when it gets running
again I'll let you know. B&C want $45 to look at it and verify it was not
there regulator.
Hope this helps,
Dale Martin
Lewiston, ID
LEZ-235
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Help with Diagnosis
>
> >
> >
> >My already flying when I bought it RV 6 A has a B&C alternator and a
> >LR3C-14 voltage regulator. The builder used a 10 amp fuse in the Field
> >line.
>
> This is contrary to recommended installation. Suggest you consider
> rewiring to include the suggested 5A breaker per installation
> instructions.
>
> > Some months ago when I had a low battery, an attempt to jump the
> >battery got a lot of sparks in the vicinity of the LR3C-14.
>
> I am always concerned about reports of "sparks" wherein their
> source is not researched and identified. See chapter 17 of
> the 'Connection for another sparks-outta-nowhere story.
>
>
> > About 3 flying
> >hours later the fuse blew and we got home on the battery. Today the fuse
> >blew again. We landed and replaced the fuse. Everything seemed OK
during
> >taxi and run-up, but the fuse blew again shortly after take-off. Got home
> >on battery again. Since my home airport is in the DC ADIZ this needs to
be
> >fixed properly. Where do I start to look? A short in the field wire is
> >the first place, what next? Thanks in advance for the help.
>
> Do you have any idea where the sparks came from? How
> did you observe them? You either have a wiring problem
> or the crowbar ov system in the LR3 is being tripped.
> How old is the LR-3? There was a mod to the design to
> fix an nuisance tripping problem with the OV system but
> since your problems seem to post-date another issue
> (sparks) with un-explained origin, the LR-3 may be fine
> and only the wiring needs investigation. If it were my
> airplane, I'd install the recommended 5A breaker, install
> ALL new wiring in the field supply circuit and see if
> the problem goes away.
>
> If it's still tripping the breaker, we'll need to dig
> further.
>
> Bob . . .
>
>
________________________________________________________________________________
From: | "Phil Birkelbach" <phil(at)petrasoft.net> |
Subject: | Re: Weird LED fuse behavior |
I have seen some fuses lately that had some resistance in them. If there is
any resistance in the fuse the LED will glow. Try replacing the fuse and
see if that helps.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Baffles / Cowling
http://www.myrv7.com
----- Original Message -----
From: "John Slade" <sladerj(at)bellsouth.net>
Subject: AeroElectric-List: Weird LED fuse behavior
>
> Here's a strange one for someone....
>
> I have those fuses with an LED that lights up when they blow.
>
> When running my engine for the first time I notice that the LED for the
fuel
> injection computer (on the essential buss) is glowing, and that the glow
> changes in intensity with rpm - i.e. I can light it up more by pushing the
> throttle. On shut down I find that the fuse is not blown. I'm not seeing
any
> charge on the buss from the alternator, and I'm wondering if this may have
> something to do with it. Perhaps the alternator solenoid is open, but I
> can't see how that would affect voltage or cause some sort of reverse flow
> effect.
>
> Any ideas anyone?
> John Slade
> Cozy IV turbo rotary - making noise
>
>
________________________________________________________________________________
From: | Dave Morris <dave(at)davemorris.com> |
Subject: | Re: batteries and diode isolation |
Well, the circuit I'm referring to is here:
http://sharkey.servebeer.com/~michael/christavia/electrics/batt_schematic_rev3.jpg
It would seem to have all the features we want.
Dave Morris
>
>
> >
> >Bob, I'd like to understand better why you prefer to use contactors and
> >separate buses for 2 batteries, as opposed to diodes and allowing both
> >batteries to feed the same bus.
> >
> >I recently saw an elegant circuit that does this and allows both batteries
> >to be charged by the alternator at the same time.
> >
> >I have read your treatise on battery isolation so many times I can almost
> >quote it, but nowhere do you address the possibility that there might be a
> >way of allowing 3 electrical sources to "automatically" determine - using
> >diodes - which ones will be feeding the loads. It would seem to require so
> >much less pilot workload than flipping switches to cut in and out
> >batteries, requires less current than supporting 2 battery contactors, and
> >would still elegantly support the concept of annual battery rotation, low
> >voltage notification, etc.
> >
> >Diodes are available now with voltage drop of 0.3V and with max forward
> >currents of 240A, so the diodes themselves would not seem to be an issue.
>
> Without seeing a schematic of what you propose, it's difficult
> to assess characteristics of the system. How would you incorporate
> diodes into a system that (1) provides pilot-operated disconnection
> of batteries and (2) parallels batteries as needed for cranking?
>
> It's not that diodes are evil devices, for all the benefits they
> bring, they do not substitute for some system requirements
> include the items cited above. Once you add switches or contactors
> to orchestrate these features, the diodes are not especially
> helpful and certainly not necessary.
>
> We use lots of diodes in the power distribution of biz-jets
> and the like . . . but they're always used like the e-bus
> normal feed path diode - to provide no-moving parts isolation between
> sections of the distribution system where cranking and
> disconnection issues are not part of the design.
>
> Bob . . .
>
>
Dave Morris
________________________________________________________________________________
From: | Matt Jurotich <mjurotich(at)hst.nasa.gov> |
Subject: | Re: Help with Diagnosis |
My already flying when I bought it RV 6 A has a B&C alternator and a
LR3C-14 voltage regulator. The builder used a 10 amp fuse in the Field line.
This is contrary to recommended installation. Suggest you consider
rewiring to include the suggested 5A breaker per installation instructions.
Agreed, plan to make a major panel upgrade to IFR and electrical system
upgrade to Z13, dual alt -single battery in about 2 months. Plane has 320
plus hours with this screwy setup and wanted to fly the spring season VFR
without moding existing panel.
> Some months ago when I had a low battery, an attempt to jump the
>battery got a lot of sparks in the vicinity of the LR3C-14.
I am always concerned about reports of "sparks" wherein their
source is not researched and identified. See chapter 17 of
the 'Connection for another sparks-outta-nowhere story.
SPARKs came from my clumsy attempt to attach positive of jumper cable to
amp-meter (load meter?) shunt. Cable not attached to source nor to ground
side of planes battery. Sparks melted insulation on wires to voltmeter and
amp-meter. Taped the melted sections. Took battery out of plane and
charged it on the ground. LR 3C-14 is vintage 1994. Plane has been flying
since 1995. Put in new battery last month--B&C 25 amp hour. Last 2 trips
were with new battery in place.
Big snip
When I did an archive search, I read many posts about nuisance trips and I
inferred they could be caused by a significant load increase. Therefore I
am concerned that I need to be looking for an intermittent short in
something other than field wire or an intermittent load increase in
something like my noisy RC Allen electrical Attitude Indicator. But no
other fuses blow and and every thing works. Could sparks have caused
degraded insulation more than a few inches from their location?
Thanks
Matthew M. Jurotich
NASA/Goddard Space Flight Center
Swales contractor to the
JWST ISIM Systems Engineer
m/c : 443
e-mail mail to:
phone : 301-286-5919
fax : 301-286-7021
JWST URL: <http://ngst1.gsfc.nasa.gov
________________________________________________________________________________
From: | "David Carter" <dcarter(at)datarecall.net> |
Subject: | Re: Battery dumps |
Bob & Paul,
Thank you for the continuing excellent analysis and discussion - I feel sure
that "at the end of the tunnel" of this "thread", we are going to 1) have
another innovative, well-peer-reviewed addition to our OBAM bus
architecture - to deal with this "battery dump/surge" phenomenon, or, 2)
have some really clear understanding of some "required" "pilot operating
procedures to avoid 'economically un-fixable' bus architecture limitations",
and, maybe, 3) an optional 'economically stressful fix' to the problem
(e.g., "power conditioner" that Bob mentioned - many of us are using engine
monitors and electronic fuel injection and electronic ignition controllers
with computer boards and some are likely NOT DO-160 qual'd - stuff that we
need to protect in order to stay airborne, as well as MicroEncoders and
other NON-essential gadgets that we'd like to keep out of the "frying pan"
so as to save our wallets.)
Looking forward to the evolution of this thing. Both of you are being real
gentlemen as you discuss this - and no, I don't believe Bob "has his mind
made" up [on 'everything' - my words] - just strong and reasonable
"engineering-economic-opertor tradeoff" views on some parts of the problem
and its analysis. You are both hanging in there quite well. Thank you
both for what you are doing for our OBAM community.
Paul, if this project stresses your finances, don't hesitate to ask us to
make contributions to help out.
Perhaps (hopefully) a 4th outcome will occur - a "consumer campaign" to have
all of our OBAM equipment vendors add "surge" protection, if not already
there. However, this current study by Paul and supported by Bob will likely
provide some additional "technical foundation" and some "tested solutions"
that may well be the basis for introducing this topic to those vendors who
have not yet considered or designed for the DO-160 surge issue. This would
be a great topic for an Oshkosh Forum Tent. That would be a great way to
get fast and widespread distribution of the essential features of "problem
analysis and range of solutions".
David Carter
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Re: Battery dumps
>
> >
> >
> >For Bob N. & Paul Messinger, especially, and Eric Jones: I've studied
the
> >sharing of ideas and views on this Battery Dump thing. I believe Mike
> >Holland's e-mail below (part), which mentions "big in-line fuse" type
> >device. Fuses & CB all have a "time rating". I believe a big B-Lead
fuse
> >or limiter would be a "slow blow" item.
>
> Correct. Like all "fuses" and breakers, these devices are for one
> purpose only, protect wires and the rest of the system from the effects
> from hard faults (very high current up to dead shorts). These devices
> never figure into the OV (failed regulator) or battery-dump (transient
> surges) event. Many folks confuse the role of the 5A alternator
> control breaker as an integral part of the OV protection scheme when
> teamed with a crowbar OV module. Yes, the breaker does open in
> response to a high current DELIBERATELY GENERATED BY THE CROWBAR
> OV MODULE. The breaker is not providing a first order response to
> the ov condition, only a second order response to the protection
> module which is the actual OV event sensor. If no first order OV
> protection is provided (crowbar OV module or OV relay) then a
> failed regulator can precipitate a series of very expensive events
> without opening a single breaker or fuse.
>
> > - I think the discussion should be momentarily limited so we (you!)
> >focus on the 1 thing that I believe has not, so far, been isolated out
and
> >clearly addressed/responded to: "Time or Duration of the Event before it
is
> >'killed'. "
>
> Correct.
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Weird LED fuse behavior |
>
>
>I have seen some fuses lately that had some resistance in them. If there is
>any resistance in the fuse the LED will glow. Try replacing the fuse and
>see if that helps.
>
>Godspeed,
I'm mystified by this symptom. Red LEDs take about 2 volts
to get any light out of them. There's no fuse that should
have a 2 volt drop across it without being blown open.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Altitude Encoder data sharing |
>
>Comments/Questions: Hi Bob! I'm looking for a clean way to "tee" into my
>encoder for a GPS install.
>I hate to use butt connectors. Wondering if someone makes a D sub tee or
>breakout of some kind.
> Thanks for any ideas! Tim
Don't know of anyone that makes such a critter. It would
be difficult to do a "universal" device because some
items of equipment added to the altitude data lines
also need isolation diodes in the circuit. This needs
to be researched and complied with as necessary
for your particular pieces of equipment.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Troy Scott" <tscott1217(at)bellsouth.net> |
Subject: | ?punch for Carling? |
Gentlemen,
I'm thinking there must be a better way to mount the Carling switches than
drilling two holes in the panel. I don't want the extra "position locking"
hole. Is there a punch that cuts the hole and leaves the key that keeps the
switch from rotating?
Regards,
Troy Scott
tscott1217(at)bellsouth.net
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Battery dumps and Environmental Robustness |
>
>
>Bob & Paul,
>
>Thank you for the continuing excellent analysis and discussion - I feel sure
>that "at the end of the tunnel" . . .
Dave, thank you for the kind words along with your perceptions
of where we think we're going and how we're planning to get there.
I am pleased that the goals appear as you have described them for that
is certainly my wish . . .
>Perhaps (hopefully) a 4th outcome will occur - a "consumer campaign" to have
>all of our OBAM equipment vendors add "surge" protection, if not already
>there. However, this current study by Paul and supported by Bob will likely
>provide some additional "technical foundation" and some "tested solutions"
>that may well be the basis for introducing this topic to those vendors who
>have not yet considered or designed for the DO-160 surge issue. This would
>be a great topic for an Oshkosh Forum Tent. That would be a great way to
>get fast and widespread distribution of the essential features of "problem
>analysis and range of solutions".
Years ago, I published a list of questions that folks could
paste to a note-card and carry around during their visits to
the various booths at OSH and elsewhere. The questions had to
do with information gathering about the manufacturer's awareness
and willingness to apply any level of environmental robustness
to his/her products. Whether or not DO-160 was embraced
was immaterial. The point was that EVERY manufacturer should
be aware of a degree of consumer concerns about such matters and
find it to be in their own best interests to address those concerns.
This is exactly how the free market is supposed to work and WILL
if we properly exercise our prerogatives as knowledgeable,
responsible consumers.
I suggested that if answers to the questions at the booth were
less than satisfactory, one could say, "Gee, I REALLY do like your
product and I'd consider getting one right away . . . but there
IS a matter of environmental fragility. I'm going to have to think
about this awhile. I think I'll check with your competitors to see
how they've address the issues of learning to live in the real world
of airplanes."
Now, if you really want to install the product in your
airplane, you can call them on the phone or perhaps order it on
the Internet later. The value in this exercise is the view
of your retreating backside by the person(s) in the booth who
could not sell you a product for what just might be silly
reasons. You don't have to tell them later that you were the
"sale they missed" at the booth. That bit of data needs to
simmer in their marketing minds for awhile if it's going to
bear fruit.
I'd be pleased to do such a forum at OSH . . . if I can
ever figure out a practical way to make another trip to
OSH. B&C used to pay most of my expenses if I helped in
their booth. Sales of books would just about wash out
out-of-pocket expenses for making the trip. Hmmmm . . .
maybe I could do a weekend seminar just before OSH
and in the vicinity so that I could tie the two activities
together. That MIGHT play.
Further, I'll renew my offer that should any of you on
the list discover an otherwise desirable product lacking
in environmental robustness, I'd be pleased to advise
those folks at no charge for the initial consultation
and recommendations. I have lots of customers who compete
with each other that know I can keep their secrets.
Give them my e-mail address. I've had several takers
over the past ten years . . . but far too few.
Bob . . .
________________________________________________________________________________
Subject: | Re: batteries and diode isolation |
From: | "George Braly" <gwbraly(at)gami.com> |
Dave,
After a quick look, I wonder just exactly you would try to sense the
buss voltage for the voltage regulator for the alternator???
George
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dave
Morris
Subject: Re: AeroElectric-List: Re: batteries and diode isolation
Well, the circuit I'm referring to is here:
http://sharkey.servebeer.com/~michael/christavia/electrics/batt_schemati
c_rev3.jpg
It would seem to have all the features we want.
Dave Morris
>
>
> >
> >Bob, I'd like to understand better why you prefer to use contactors
and
> >separate buses for 2 batteries, as opposed to diodes and allowing
both
> >batteries to feed the same bus.
> >
> >I recently saw an elegant circuit that does this and allows both
batteries
> >to be charged by the alternator at the same time.
> >
> >I have read your treatise on battery isolation so many times I can
almost
> >quote it, but nowhere do you address the possibility that there might
be a
> >way of allowing 3 electrical sources to "automatically" determine -
using
> >diodes - which ones will be feeding the loads. It would seem to
require so
> >much less pilot workload than flipping switches to cut in and out
> >batteries, requires less current than supporting 2 battery
contactors, and
> >would still elegantly support the concept of annual battery rotation,
low
> >voltage notification, etc.
> >
> >Diodes are available now with voltage drop of 0.3V and with max
forward
> >currents of 240A, so the diodes themselves would not seem to be an
issue.
>
> Without seeing a schematic of what you propose, it's difficult
> to assess characteristics of the system. How would you incorporate
> diodes into a system that (1) provides pilot-operated disconnection
> of batteries and (2) parallels batteries as needed for cranking?
>
> It's not that diodes are evil devices, for all the benefits they
> bring, they do not substitute for some system requirements
> include the items cited above. Once you add switches or contactors
> to orchestrate these features, the diodes are not especially
> helpful and certainly not necessary.
>
> We use lots of diodes in the power distribution of biz-jets
> and the like . . . but they're always used like the e-bus
> normal feed path diode - to provide no-moving parts isolation
between
> sections of the distribution system where cranking and
> disconnection issues are not part of the design.
>
> Bob . . .
>
>
Dave Morris
==
==
==
==
________________________________________________________________________________
From: | "bryan hooks" <hook3607(at)bellsouth.net> |
Subject: | Runaway stab trim prevention |
Saw a post today on one of the other email groups about the effects of
runaway stab trim on an RV. Does anyone have (or know how to make) some
sort of automatic cutout switch that would stop a runaway trim if it ran
continuously for some number of seconds? Maybe some sort of setup with
a reset switch.
I bet Bob could lick this in less time than it took me to write this
email. :-)
Bryan Hooks
RV-7A, slow, empennage
Knoxville, TN
Hook3607(at)bellsouth.net
________________________________________________________________________________
From: | "Alex Peterson" <alexpeterson(at)earthlink.net> |
Subject: | ?punch for Carling? |
> Gentlemen,
>
> I'm thinking there must be a better way to mount the Carling
> switches than drilling two holes in the panel. I don't want
> the extra "position locking" hole. Is there a punch that
> cuts the hole and leaves the key that keeps the switch from rotating?
>
> Regards,
> Troy Scott
> tscott1217(at)bellsouth.net
Troy, another option is to drill the locking hole only about half the
depth of the panel, from the back (foreward in plane) side. You might
be able to put a threaded drill bit into a microstop to limit the depth.
It would not be hard to make a little jig to locate the locking hole.
Then, bend the locking tab enough so that it can be used on the switch
side of the panel.
Alex Peterson
Maple Grove, MN
RV6-A N66AP 443 hours
http://www.home.earthlink.net/~alexpeterson/
________________________________________________________________________________
From: | "Alex Peterson" <alexpeterson(at)earthlink.net> |
Subject: | Runaway stab trim prevention |
> Saw a post today on one of the other email groups about the
> effects of runaway stab trim on an RV. Does anyone have (or
> know how to make) some sort of automatic cutout switch that
> would stop a runaway trim if it ran continuously for some
> number of seconds? Maybe some sort of setup with a reset switch.
>
> I bet Bob could lick this in less time than it took me to
> write this email. :-)
>
> Bryan Hooks
> RV-7A, slow, empennage
> Knoxville, TN
> Hook3607(at)bellsouth.net
What for? I'd put some sort of pullable breaker or disconnect switch on
the panel for that situation. These things fly without much effort with
trim full, provided one keeps the speed down to flap speed or not far
above.
Alex Peterson
Maple Grove, MN
RV6-A N66AP 443 hours
http://www.home.earthlink.net/~alexpeterson/
________________________________________________________________________________
From: | "bryan hooks" <hook3607(at)bellsouth.net> |
Subject: | Runaway stab trim prevention |
I would still advocate having a CB or a fuse, but an automatic cut-out
switch that stopped it at say, 2 seconds of continual trim, would stop
it before it ever became an issue. There would be no need to find a CB
while flying an out of trim airplane in the weather, etc...
I'm not necessarily sold on the idea or anything, it was just a thought.
But if it's a cheap addition, I think it'd be pretty slick.
-bryan
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Alex
Peterson
Subject: RE: AeroElectric-List: Runaway stab trim prevention
> Saw a post today on one of the other email groups about the
> effects of runaway stab trim on an RV. Does anyone have (or
> know how to make) some sort of automatic cutout switch that
> would stop a runaway trim if it ran continuously for some
> number of seconds? Maybe some sort of setup with a reset switch.
>
> I bet Bob could lick this in less time than it took me to
> write this email. :-)
>
> Bryan Hooks
> RV-7A, slow, empennage
> Knoxville, TN
> Hook3607(at)bellsouth.net
What for? I'd put some sort of pullable breaker or disconnect switch on
the panel for that situation. These things fly without much effort with
trim full, provided one keeps the speed down to flap speed or not far
above.
Alex Peterson
Maple Grove, MN
RV6-A N66AP 443 hours
http://www.home.earthlink.net/~alexpeterson/
==
==
==
==
________________________________________________________________________________
From: | Charlie Kuss <chaskuss(at)bellsouth.net> |
Subject: | Re: ?punch for Carling? |
Troy
Greenlee makes a 60601 punch. The old model number was a 732 radio chassis punch.
This is the purpose built punch for toggle switches. Look on page 33 of the
catalog on the web page listed below. Look for the heading KEY PUNCHES.
http://198.247.193.8/wwwroot/greenlee/holemaking.pdf
Charlie Kuss
RV-8A wiring
Boca Raton, Fl.
>
>Gentlemen,
>
>I'm thinking there must be a better way to mount the Carling switches than
>drilling two holes in the panel. I don't want the extra "position locking"
>hole. Is there a punch that cuts the hole and leaves the key that keeps the
>switch from rotating?
>
>Regards,
>Troy Scott
>tscott1217(at)bellsouth.net
>
>
________________________________________________________________________________
From: | "Bruce Gray" <Bruce(at)glasair.org> |
Subject: | ?punch for Carling? |
Insert tab washer from the back of the panel with the tab facing the
panel back. Pull the switch forward to set and hold the tab against the
panel back. Rotate the switch +/- 90 degrees. You have now made a scribe
mark on the panel back with the tab. Drill hole halfway through the
panel, from the back, on the scribe line. Done.
Or you can buy a key punch. Expensive $100 +.
Bruce
www.glasair.org
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Alex
Peterson
Subject: RE: AeroElectric-List: ?punch for Carling?
> Gentlemen,
>
> I'm thinking there must be a better way to mount the Carling
> switches than drilling two holes in the panel. I don't want
> the extra "position locking" hole. Is there a punch that
> cuts the hole and leaves the key that keeps the switch from rotating?
>
> Regards,
> Troy Scott
> tscott1217(at)bellsouth.net
Troy, another option is to drill the locking hole only about half the
depth of the panel, from the back (foreward in plane) side. You might
be able to put a threaded drill bit into a microstop to limit the depth.
It would not be hard to make a little jig to locate the locking hole.
Then, bend the locking tab enough so that it can be used on the switch
side of the panel.
Alex Peterson
Maple Grove, MN
RV6-A N66AP 443 hours
http://www.home.earthlink.net/~alexpeterson/
________________________________________________________________________________
From: | Tammy and Mike Salzman <arrow54t(at)yahoo.com> |
Subject: | Runaway stab trim prevention |
Bryan,
I went ahead and installed a "TRIM REVERSE" switch, along with "TRIM
MASTER" and "TRIM COMMAND" switches on my panel. I'm building a
Lancair ES and have lots of room for these switches. The trim reverse
switch is a DPDT (ON-0N) switch that just has jumpers soldered across
the NC of one pole to the NO of the other.(2 jumpers total) Power gets
wired to the NC or NO of respective poles and output to your trim
relays/servos comes off the COM terminals.
The plan is to be able to reverse any runaway condition, then shut off
the trim system at the TRIM MASTER.
Mike Salzman
Fairfield, CA
LNCE
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | ?punch for Carling? |
>
>Insert tab washer from the back of the panel with the tab facing the
>panel back. Pull the switch forward to set and hold the tab against the
>panel back. Rotate the switch +/- 90 degrees. You have now made a scribe
>mark on the panel back with the tab. Drill hole halfway through the
>panel, from the back, on the scribe line. Done.
>
>Or you can buy a key punch. Expensive $100 +.
>
>Bruce
>www.glasair.org
Another technique I've used is to cut the peripheral
tab completely off the keying washer. Coat one side
with thin coat of E6000 or ShoeGoo cement. Assemble
switch on panel with keying washer on back side, glued
face to the panel. Wait 24 hours before disassembly.
This genre' of cements does a good job of bonding
the keying washer to an aluminum panel. There is
slight risk of some squish-out glue getting into
switch mounting threads. It's only a slight impediment
to future disassembly and may be easily trimmed away
with an Xacto knife later.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | ?punch for Carling? |
>
>
>
> > Gentlemen,
> >
> > I'm thinking there must be a better way to mount the Carling
> > switches than drilling two holes in the panel. I don't want
> > the extra "position locking" hole. Is there a punch that
> > cuts the hole and leaves the key that keeps the switch from rotating?
> >
> > Regards,
> > Troy Scott
> > tscott1217(at)bellsouth.net
>
>Troy, another option is to drill the locking hole only about half the
>depth of the panel, from the back (foreward in plane) side. You might
>be able to put a threaded drill bit into a microstop to limit the depth.
>It would not be hard to make a little jig to locate the locking hole.
>Then, bend the locking tab enough so that it can be used on the switch
>side of the panel.
I did a little piece on this a few years ago and posted it
to
http://www.aeroelectric.com/articles/switchmounting/switchmounting.html
A unibit works as good or better than a spotfacer.
Bob . . .
________________________________________________________________________________
From: | Dave Morris <dave(at)davemorris.com> |
Subject: | Runaway stab trim prevention |
You can't put a limit switch on each end of the trim control so that the
motor can only run to the limit and then only a reversal can back it out
again? That's the way I'm doing all my trim servos. Very simple.
Dave Morris
At 08:24 PM 3/1/2004, you wrote:
>
>
>Bryan,
>
>I went ahead and installed a "TRIM REVERSE" switch, along with "TRIM
>MASTER" and "TRIM COMMAND" switches on my panel. I'm building a
>Lancair ES and have lots of room for these switches. The trim reverse
>switch is a DPDT (ON-0N) switch that just has jumpers soldered across
>the NC of one pole to the NO of the other.(2 jumpers total) Power gets
>wired to the NC or NO of respective poles and output to your trim
>relays/servos comes off the COM terminals.
>
>The plan is to be able to reverse any runaway condition, then shut off
>the trim system at the TRIM MASTER.
>
>Mike Salzman
>Fairfield, CA
>LNCE
>
>
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: batteries and diode isolation |
>
>Well, the circuit I'm referring to is here:
>http://sharkey.servebeer.com/~michael/christavia/electrics/batt_schematic_rev3.jpg
>
>It would seem to have all the features we want.
I'm a bit mystified by the schematic. It appears that the designer
was worried about battery failure . . . two batteries are diode
or'ed to feed the bus and ignition with the ignition system bypassing
a "master switch" which I presume is the battery contactor. Then
there are three more diodes on the alternator output. . . one each
to charge batteries and a third to bypass the batteries and drive
system loads whether or not the batteries are "good" . . .
The drawing also calls for a two-pole starter contactor. Since
we don't have two-pole devices in low cost versions, I suspect
we'd end up with two separate contactors to implement the two
pole function. By my count, we have three contactors and five
power diode assemblies. Further, since cranking current doesn't
come through the battery master contactor, we cannot make the
starter feed cable do dual duty service for tying the batteries
to the rest of the system. In this case, the starter contactor(s)
would have to be mounted right at the battery. Single, intermittant
duty starter contactor draws about 5A, so a pair would draw 10A.
Figure Z-11 with a Z-30 aux battery option, we STILL have three
contactors and only one relatively small diode to implement a
relatively independent 4-bus system where busses may be assigned
to mutually exclusive tasks. What operational failure can you
deduce where the Z-11/Z-30 falls short of what the 3-contactor/5-diode
arrangement provides?
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Help with Diagnosis |
> I am always concerned about reports of "sparks" wherein their
> source is not researched and identified. See chapter 17 of
> the 'Connection for another sparks-outta-nowhere story.
>
>SPARKs came from my clumsy attempt to attach positive of jumper cable to
>amp-meter (load meter?) shunt. Cable not attached to source nor to ground
>side of planes battery. Sparks melted insulation on wires to voltmeter and
>amp-meter. Taped the melted sections. Took battery out of plane and
>charged it on the ground. LR 3C-14 is vintage 1994. Plane has been flying
>since 1995. Put in new battery last month--B&C 25 amp hour. Last 2 trips
>were with new battery in place.
Aha! A much clearer picture.
>
>
>When I did an archive search, I read many posts about nuisance trips and I
>inferred they could be caused by a significant load increase.
Actually, the two most significant sources for nuisance tripping
the LR-3 crowbar ov protection system are: (1) Noises (very short duration
spikes) generated by closing a switch to a heavy load
or opening a switch to un-clamped contactor or relay coil
and (2)longer duration bumps in bus voltage caused by instability
of regulator due to wiring resistance increases coupled with load
changes (usually switch openings) combined with high resistance
wiring between bus and the regulator that severely destabilizes it.
The condition can be exacerbated by a soggy battery.
> Therefore I
>am concerned that I need to be looking for an intermittent short in
>something other than field wire or an intermittent load increase in
>something like my noisy RC Allen electrical Attitude Indicator. But no
>other fuses blow and and every thing works. Could sparks have caused
>degraded insulation more than a few inches from their location?
Probably not. First, your LR-3 is old enough to NOT have received
the modification added a few years back to offset conditions cited
in (1) above. We had some Bonanzas with some gawd-awful mil-spec
switches in the landing and taxi light circuits that bounced REALLY
bad. Turning taxi and landing lights on at the same time would trip
the OV circuit when in fact no OV condition was present.
This is an easy mod to add. I can do it for you if you want to
send me your regulator.
Having said that, I'm wondering why this is a new condition.
How old is the battery? What kind of battery? If it were
my airplane and the battery was more than a year old, I'd
put in a new RG battery and re-wire the regulator to have
the recommended breaker. Then fly the airplane and see if
the breaker trips. If so, does it do it randomly or in response
to some action or activity in the electrical system.
The reason you found quite a few articles on nuisance tripping
is because that's the majority of ALL articles concerning the
LR-3 series regulators. Out of thousands in service, nuisance
tripping has been a problem in a small percentage of the total
and for the most part, the only problem we've encountered. It's
usually easy to track down and fix root cause. Let's get the
system updated a bit and research it from there.
Bob . . .
________________________________________________________________________________
From: | "Ted Lemen" <tedlem(at)ecentral.com> |
We purchased several crimpers from B&C and included was the RCT-3. It is
supposed to be for the D sub pins but when you sart clamping down on the
pin, you can't release it until you have squeezed all of the way down
and that just about ruins the pin. By the time you can release it the
opening is really small I have used the hex crimper using the .043 slot
which seems to work alright.
________________________________________________________________________________
From: | "Ted Lemen" <tedlem(at)ecentral.com> |
I thought I asked this question before but Bob, can you use the "hex
BNC" crimper that B&C sells on the amp round BNC connectors? I tried one
and it looked OK.
________________________________________________________________________________
From: | "Ted Lemen" <tedlem(at)ecentral.com> |
Is it acceptable to use the "hex" crimper that B&C sells with the amp
round BNC connectors? I tried one and it seemed OK.
________________________________________________________________________________
From: | Fiveonepw(at)aol.com |
Subject: | Re: Runaway stab trim prevention |
In a message dated 03/01/2004 7:03:07 PM Central Standard Time,
hook3607(at)bellsouth.net writes:
I would still advocate having a CB or a fuse, but an automatic cut-out
switch that stopped it at say, 2 seconds of continual trim, would stop
it before it ever became an issue. There would be no need to find a CB
while flying an out of trim airplane in the weather, etc...
This would be neat, but more stuff may not always be the best way to tackle
this kind of problem. I want anything electrically controlling a flight
surface as dead-simple as possible. If you NEEDED more than 2 seconds of trim
motion could you do without it if automatically disconnected? Would you recognize
a runaway trim event within 2 seconds? How's your reaction time? (How long
would it take to hit the master switch?) This is one reason my trim and wing
leveler are fed from the Main bus and another justification for the E-bus...
Mark
________________________________________________________________________________
From: | Fiveonepw(at)aol.com |
Subject: | Re: Runaway stab trim prevention |
In a message dated 03/01/2004 7:03:07 PM Central Standard Time,
hook3607(at)bellsouth.net writes:
I would still advocate having a CB or a fuse, but an automatic cut-out
switch that stopped it at say, 2 seconds of continual trim, would stop
it before it ever became an issue. There would be no need to find a CB
while flying an out of trim airplane in the weather, etc...
This would be neat, but more stuff may not always be the best way to tackle
this kind of problem. I want anything electrically controlling a flight
surface as dead-simple as possible. If you NEEDED more than 2 seconds of trim
motion could you do without it if automatically disconnected? Would you recognize
a runaway trim event within 2 seconds? How's your reaction time? (How long
would it take to hit the master switch?) This is one reason my trim and wing
leveler are fed from the Main bus and another justification for the E-bus...
Mark
________________________________________________________________________________
From: | Dave Morris <dave(at)davemorris.com> |
Subject: | Re: batteries and diode isolation |
At 09:39 PM 3/1/2004, you wrote:
> >
> >Well, the circuit I'm referring to is here:
> >http://sharkey.servebeer.com/~michael/christavia/electrics/batt_schematic
> _rev3.jpg
> >
> >It would seem to have all the features we want.
>
>
> Figure Z-11 with a Z-30 aux battery option, we STILL have three
> contactors and only one relatively small diode to implement a
> relatively independent 4-bus system where busses may be assigned
> to mutually exclusive tasks. What operational failure can you
> deduce where the Z-11/Z-30 falls short of what the 3-contactor/5-diode
> arrangement provides?
>
Well, for one thing, I think the requirement to separate out loads into 4
different busses, not knowing which of those busses might be the one that
fails, is a liability that this schematic avoids. You don't have to play
Sophie's choice with your electrical loads. I personally find it difficult
to decide which of my loads are "non-essential" (with the obvious exception
of the CD player!). Doesn't this circuit allow you to turn your entire
electrical system into one giant "essential bus" and an "always hot bus"
(i.e. ignition in this diagram), avoid the constant drain of multiple
battery contactors, and eliminate the pilot from the equation totally by
handling all the source switching automatically with solid state components
that have no moving parts?
Dave Morris
________________________________________________________________________________
From: | "Jeffrey W. Skiba" <jskiba(at)icosa.net> |
Subject: | Runaway stab trim prevention |
I am a little confused or I guess I have a question as to how this would
operate,
I understand that if the trim ran for more than the X time say 2 seconds
that it would automatically shut OFF, would this also include intentional
operation (I would think so) so what happens if you were actually trimming
and needed more than the two seconds worth ? Would you have to press a reset
button or something??
I guess my next question is to the entire group ?
HOW LONG should the auto-time out be 2 seconds 3 seconds or what ??
Just some thoughts
Jeff.
hook3607(at)bellsouth.net writes:
I would still advocate having a CB or a fuse, but an automatic cut-out
switch that stopped it at say, 2 seconds of continual trim, would stop it
before it ever became an issue. There would be no need to find a CB while
flying an out of trim airplane in the weather, etc... This would be neat,
but more stuff may not always be the best way to tackle
this kind of problem. I want anything electrically controlling a flight
surface as dead-simple as possible. If you NEEDED more than 2 seconds of
trim
motion could you do without it if automatically disconnected? Would you
recognize
a runaway trim event within 2 seconds? How's your reaction time? (How long
would it take to hit the master switch?) This is one reason my trim and
wing
leveler are fed from the Main bus and another justification for the E-bus...
Mark
________________________________________________________________________________
From: | "Dale Martin" <niceez(at)cableone.net> |
Subject: | Re: Harmonic Balancer |
I'm digging around looking for my 22AWG Tefzel wire and what do I find?
A Mark Landoll Harmonic Dampener!
Still shines like new. New was $375 + shipping ....
Save $100 -
Sell for $275 plus shipping from 83501 zip code.
All hardware to mount to Lycoming flywheel and mounting instructions
included.
Pictures on request. Really smooths out a two blade prop.
Dale Martin
Lewiston, ID
LEZ-235
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: RCT-3 crimper |
>
>We purchased several crimpers from B&C and included was the RCT-3. It is
>supposed to be for the D sub pins but when you start clamping down on the
>pin, you can't release it until you have squeezed all of the way down
>and that just about ruins the pin. By the time you can release it the
>opening is really small I have used the hex crimper using the .043 slot
>which seems to work alright.
I am mystified by your comments. The RCT-3 tool IS for machined
D-sub pins and we've sold hundreds of these tools. I give away
a half dozen or so at each weekend seminar. I've not seen or
heard of the problem you describe.
Here's a d-sub pin I just installed with an RCT-3 from my
own toolbox:
http://www.aeroelectric.com/Pictures/RCT-3_Male.jpg
How does this picture differ from the results you're getting?
The tool is designed for a complete, controlled stroke for crimping
the pins. I suppose the tool you have may be defective. You can
send it to me at 6936 Bainbridge Road, Wichita, KS 67226 for
an inspection. I'll have B&C replace it if necessary.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Is it acceptable to use the "hex" crimper that B&C sells with the amp
>round BNC connectors? I tried one and it seemed OK.
Don't know from first hand experience. If B&C is still selling
the same connectors and tools I used to sell, I can say that
the tool works well with the connectors we supplied for RG-58,
RG-400 and RG-142.
If it looked okay and passed a reasonable pull test (10 pounds)
then it's probably alright.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | Mickey Coggins <mick-matronics(at)rv8.ch> |
Subject: | Re: Runaway stab trim prevention |
Has this actually happened to someone? What would cause it?
Is there a way to avoid the problem? Sounds kind of nasty.
>Saw a post today on one of the other email groups about the effects of
>runaway stab trim on an RV. ....
--
Mickey Coggins
http://www.rv8.ch/
#82007 QB Wings/Fuselage
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: batteries and diode isolation |
>
>At 09:39 PM 3/1/2004, you wrote:
>
> > >
> > >Well, the circuit I'm referring to is here:
> > >http://sharkey.servebeer.com/~michael/christavia/electrics/batt_schematic
> > _rev3.jpg
> > >
> > >It would seem to have all the features we want.
> >
> >
> > Figure Z-11 with a Z-30 aux battery option, we STILL have three
> > contactors and only one relatively small diode to implement a
> > relatively independent 4-bus system where busses may be assigned
> > to mutually exclusive tasks. What operational failure can you
> > deduce where the Z-11/Z-30 falls short of what the 3-contactor/5-diode
> > arrangement provides?
> >
>
>Well, for one thing, I think the requirement to separate out loads into 4
>different busses, not knowing which of those busses might be the one that
>fails, is a liability that this schematic avoids. You don't have to play
>Sophie's choice with your electrical loads. I personally find it difficult
>to decide which of my loads are "non-essential" (with the obvious exception
>of the CD player!). Doesn't this circuit allow you to turn your entire
>electrical system into one giant "essential bus" and an "always hot bus"
>(i.e. ignition in this diagram), avoid the constant drain of multiple
>battery contactors,
It doesn't eliminate battery contactors. I presume the master
switch was a contactor . . . if it's a real switch, keep in mind
that it needs to mount close to the battery. Like 6" wires between
battery and siwtch.
> . . . and eliminate the pilot from the equation totally by
>handling all the source switching automatically with solid state components
>that have no moving parts?
First, the essential bus is not really for ESSENTIAL equipment.
Reread chapter 17 and think in terms of ENDURANCE instead of
ESSENTIAL. The stuff that goes on this bus are items you need for
continued flight in cruise configuration to airport of intended
destination. Battery bus is for things the engine needs to keep
running that require DC power. There should be no truly essential
items in your airplane that are not backed up. Essential things
are those that make the airplane come down or increase your risk
of hitting something hard. They generally do no include exterior
lights, engine instrumentation, supper-whippy panel lighting,
etc. If you have any one thing wherein failure causes you to
break a sweat, then you better have a backup for it. So, the
philosophy is that when everything essential is backed up,
there are no single failures that put the outcome of the flight
in doubt . . . i.e. no single thing is essential to flight.
This is a VERY short list of things. Further, we're assuming you'll
not treat your airplane like a C-172 and will do preventative
maintenance on the battery or batteries. You are not going to
experience an electrical emergency if you've planned your system
with reasonable care and understand how it operates.
Post your list of goodies and get some suggestions as to
how they can be powered from the various busses to provide
failure tolerance. What makes you think you need two batteries?
Do you plan to have a vacuum system?
This is a simpler task that you realize . . . that maze
of diodes to relieve you of having to make design decisions
creates more hazards than it eliminates.
Bob . . .
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
Subject: | Re: Battery dumps |
Thanks for your support. I am fine, just see no need to spend thousands on
brand name equipment that may/may not meet DO-160. Also ever try to find out
just what the equipment really was tested to; say from King etc etc. Best
of luck truing to get that info from most any mfgr. Statements meeting
DO-160 or other \specs seldom are informative as which parts etc were met
and which parts were not tested or was it all engineering and no testing.
I fall back on common sense engineering as learned in aerospace where lots
of discussions with EMC group and lab drove what worked and what did not
work..
I have a auto engine conversion and find that requires a somewhat different
design approach. Also most automotive design standards appear to greatly
exceed what I can learn about DO-160 (which is darn little).
As far as DO-160 I do not know if it covers the load dump of the current
discussion and I am waiting for Bob to extract what HV pulse it tests to. As
an unprotected spike can exceed 50V the test of 20v or 30 v is not adequate
in my opinion and seems to be related to OVP not load dump protection.
I am working with another person off line that perhaps has a solution that
will be simple and keep the peak voltage under 20V, At least the potential
is that good. When the development is done He will be the one to announce as
its based on his input to the problem.
Expect it to take a month however to complete.
At this point I am waiting for info from Bob on what DO-160 tests to with
regard to spikes. Also perhaps the test circuit used.
We have what the auto industry tests to for load dump.
I wonder if DO-160 even addresses load dump effects on the equipment??
Who can tell, I sure cannot as Buying a copy is not in my budget.
This is a common problem where Standards are not public and one has to buy
the standard at manufacturers high prices.
Paul
----- Original Message -----
From: "David Carter" <dcarter(at)datarecall.net>
Subject: Re: AeroElectric-List: Re: Battery dumps
>
> Bob & Paul,
>
> Thank you for the continuing excellent analysis and discussion - I feel
sure
> that "at the end of the tunnel" of this "thread", we are going to 1) have
> another innovative, well-peer-reviewed addition to our OBAM bus
> architecture - to deal with this "battery dump/surge" phenomenon, or, 2)
> have some really clear understanding of some "required" "pilot operating
> procedures to avoid 'economically un-fixable' bus architecture
limitations",
> and, maybe, 3) an optional 'economically stressful fix' to the problem
> (e.g., "power conditioner" that Bob mentioned - many of us are using
engine
> monitors and electronic fuel injection and electronic ignition controllers
> with computer boards and some are likely NOT DO-160 qual'd - stuff that we
> need to protect in order to stay airborne, as well as MicroEncoders and
> other NON-essential gadgets that we'd like to keep out of the "frying pan"
> so as to save our wallets.)
>
>
________________________________________________________________________________
From: | Dabusmith(at)aol.com |
Subject: | Re: 912s Capacitor |
I have had both left and right Aeroflash power supplies go bad in less than
100 hours in service. My Falcon turn coordinator is not spinning up even though
the flag is not displayed.
My other systems are working perfectly. I am using Bob's wiring design
w/crowbar. Is it likely my capacitor is bad? I am inclined to think these components
failed on their own but I don't know how to tell. Would a bad capacitor cause
problems like this? My voltage in flight is steady.
Dave Smith
701 95 hr.
________________________________________________________________________________
Subject: | Re: Battery dumps |
From: | "George Braly" <gwbraly(at)gami.com> |
Yes. DO-160D does address load dumps. For both 14 and 28 volt systems.
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Paul
Messinger
Subject: Re: AeroElectric-List: Re: Battery dumps
Thanks for your support. I am fine, just see no need to spend thousands
on
brand name equipment that may/may not meet DO-160. Also ever try to find
out
just what the equipment really was tested to; say from King etc etc.
Best
of luck truing to get that info from most any mfgr. Statements meeting
DO-160 or other \specs seldom are informative as which parts etc were
met
and which parts were not tested or was it all engineering and no
testing.
I fall back on common sense engineering as learned in aerospace where
lots
of discussions with EMC group and lab drove what worked and what did not
work..
I have a auto engine conversion and find that requires a somewhat
different
design approach. Also most automotive design standards appear to greatly
exceed what I can learn about DO-160 (which is darn little).
As far as DO-160 I do not know if it covers the load dump of the current
discussion and I am waiting for Bob to extract what HV pulse it tests
to. As
an unprotected spike can exceed 50V the test of 20v or 30 v is not
adequate
in my opinion and seems to be related to OVP not load dump protection.
I am working with another person off line that perhaps has a solution
that
will be simple and keep the peak voltage under 20V, At least the
potential
is that good. When the development is done He will be the one to
announce as
its based on his input to the problem.
Expect it to take a month however to complete.
At this point I am waiting for info from Bob on what DO-160 tests to
with
regard to spikes. Also perhaps the test circuit used.
We have what the auto industry tests to for load dump.
I wonder if DO-160 even addresses load dump effects on the equipment??
Who can tell, I sure cannot as Buying a copy is not in my budget.
This is a common problem where Standards are not public and one has to
buy
the standard at manufacturers high prices.
Paul
----- Original Message -----
From: "David Carter" <dcarter(at)datarecall.net>
Subject: Re: AeroElectric-List: Re: Battery dumps
>
> Bob & Paul,
>
> Thank you for the continuing excellent analysis and discussion - I
feel
sure
> that "at the end of the tunnel" of this "thread", we are going to 1)
have
> another innovative, well-peer-reviewed addition to our OBAM bus
> architecture - to deal with this "battery dump/surge" phenomenon, or,
2)
> have some really clear understanding of some "required" "pilot
operating
> procedures to avoid 'economically un-fixable' bus architecture
limitations",
> and, maybe, 3) an optional 'economically stressful fix' to the problem
> (e.g., "power conditioner" that Bob mentioned - many of us are using
engine
> monitors and electronic fuel injection and electronic ignition
controllers
> with computer boards and some are likely NOT DO-160 qual'd - stuff
that we
> need to protect in order to stay airborne, as well as MicroEncoders
and
> other NON-essential gadgets that we'd like to keep out of the "frying
pan"
> so as to save our wallets.)
>
>
==
==
==
==
________________________________________________________________________________
From: | "Troy Scott" <tscott1217(at)bellsouth.net> |
Subject: | ?punch for Carling? |
Gentlemen,
I thought of another possibility during the night: I could add a doubler to
the panel in the area of the switches. The locking holes could be drilled
all the way through the doubler before the doubler is riveted to the panel.
Bob's solution using the modified drill bit is pretty slick too!
Regards,
Troy Scott
________________________________________________________________________________
From: | "Cy Galley" <cgalley(at)qcbc.org> |
Subject: | Re: Runaway stab trim prevention |
Was it a real situation or just the product of a vivid imagination? If it
was a real situation, and they are writing about it after the fact, it may
be more of an annoyance than a serious problem.
Cy Galley
Editor, EAA Safety Programs
cgalley(at)qcbc.org or sportpilot(at)eaa.org
----- Original Message -----
From: "Mickey Coggins" <mick-matronics(at)rv8.ch>
Subject: Re: AeroElectric-List: Runaway stab trim prevention
>
> Has this actually happened to someone? What would cause it?
> Is there a way to avoid the problem? Sounds kind of nasty.
>
> >Saw a post today on one of the other email groups about the effects of
> >runaway stab trim on an RV. ....
>
>
> --
> Mickey Coggins
> http://www.rv8.ch/
> #82007 QB Wings/Fuselage
>
>
________________________________________________________________________________
From: | "Larry Bowen" <Larry(at)BowenAero.com> |
Has anyone found an alternative to the tiny screws used to mount/secure
d-subs plugs? I'm thinking of a thumb-screw type thing. Unscrewing
those tiny screws in the close confines of a completed airplane (and
them dropping them) doesn't sound like fun. Thumb screws that would
work with or without d-sub hoods/shells would be ideal.
-
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
________________________________________________________________________________
From: | "Darwin N. Barrie" <ktlkrn(at)cox.net> |
Subject: | Re: Runaway stab trim prevention |
I am going to use the EXP buss system and have a trim disable function on
one of the switches. I bought it unlabeled to provide some flexibility for
switch assignment.
Darwin N. Barrie
Chandler AZ
----- Original Message -----
From: "Mickey Coggins" <mick-matronics(at)rv8.ch>
Subject: Re: AeroElectric-List: Runaway stab trim prevention
>
> Has this actually happened to someone? What would cause it?
> Is there a way to avoid the problem? Sounds kind of nasty.
>
> >Saw a post today on one of the other email groups about the effects of
> >runaway stab trim on an RV. ....
>
>
> --
> Mickey Coggins
> http://www.rv8.ch/
> #82007 QB Wings/Fuselage
>
>
________________________________________________________________________________
From: | "Jim Stone" <jrstone(at)insightbb.com> |
Subject: | Re: Dynon Remote Compass mounting? |
Would the metal contents in your luggage compartment like golf clubs affect
its accuracy?
Jim
----- Original Message -----
From: "Kevin Horton" <khorton01(at)rogers.com>
Subject: AeroElectric-List: Dynon Remote Compass mounting?
>
> I'm pondering the details of how to mount the remote compass sensor
> for my Dynon EFIS. I'm leaning towards hanging it from the top of
> the F-809 bulkhead on my RV-8, somewhat similar to:
>
> http://home.comcast.net/~jwdanie/Compass/compass.html
>
> But, I'm worried about potential interference from the high voltage
> strobe light line that goes from the power supply back to the tail
> strobe. I could reroute that guy lower, but it will be a real PITA.
> So, I'm wondering how close anyone has run a strobe light cable (the
> big grey one that goes from the power supply to the light) to the
> EDC-10 remote compass mount. If you've got such a strobe line in the
> area of your remote compass sensor, tell me how far away it is, and
> whether you can see any effect on heading from it.
>
> My strobe cable would probably be about 8 inches from the compass
> sensor if I don't move it. I don't want to move it if I can get away
> with it.
>
> Thanks,
> --
> Kevin Horton RV-8 (finishing kit)
> Ottawa, Canada
> http://go.phpwebhosting.com/~khorton/rv8/
>
>
________________________________________________________________________________
From: | "Vincent Welch" <welchvincent(at)hotmail.com> |
The majority of the toggle switches that I purchased came without
anti-rotation washers. I have looked in several catalogs (Newark, etc.) and
can not find them listed separately. Can one of you guys tell me where I
can buy anti-rotation washers separately?
Vince Welch
Find things fast with the new MSN Toolbar includes FREE pop-up blocking!
http://clk.atdmt.com/AVE/go/onm00200414ave/direct/01/
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Toggle Switches |
>
>
>The majority of the toggle switches that I purchased came without
>anti-rotation washers. I have looked in several catalogs (Newark, etc.) and
>can not find them listed separately. Can one of you guys tell me where I
>can buy anti-rotation washers separately?
B&C Specialy Products. E-mail Todd at mailto:todd(at)bandc.biz or call
them at 316.283.8000. They don't show as separate items in their
catalog but I think they'll make them available to you.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Dynon Remote Compass mounting? |
>
>Would the metal contents in your luggage compartment like golf clubs affect
>its accuracy?
>Jim
How far away? Any non-magnetized materials 2' or more away
will have negligible effect . . . besides, GPS in the magnetic
track mode will always be more accurate and unaffected by
local conditions.
How about putting the sensor out in a wing?
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Lowell Fitt" <lcfitt(at)inreach.com> |
Subject: | Re: Falcon Turn Coordinator |
This is a common problem as I learned. My first one quit within the
warranty period. The second one worked just beyond that. I inquired at
Falcon where I could send it or if it was even worth repairing given the
apparent service life. The response was essentially that the brushes gum up
and they promised to send cleaning instructions. I never got that
particular post, but it is easy to do. The case is opened by removing one
screw. There is an O-ring seal between the outer case and the inner, so it
is a bit of a chore to get the case removal started. Once inside the
brushes can be removed by removing a clip - I don't remember exactly how it
is configured. I cleaned the commutator with a little crocus cloth and
swabbed it out with a little denatured alcohol on a Q-tip and it has worked
this time longer than both previous times together.
Lowell
----- Original Message -----
From: <Dabusmith(at)aol.com>
Subject: AeroElectric-List: Re: 912s Capacitor
>
> I have had both left and right Aeroflash power supplies go bad in less
than
> 100 hours in service. My Falcon turn coordinator is not spinning up even
though
> the flag is not displayed.
> My other systems are working perfectly. I am using Bob's wiring design
> w/crowbar. Is it likely my capacitor is bad? I am inclined to think these
components
> failed on their own but I don't know how to tell. Would a bad capacitor
cause
> problems like this? My voltage in flight is steady.
> Dave Smith
> 701 95 hr.
>
>
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Securing d-subs |
>
>Has anyone found an alternative to the tiny screws used to mount/secure
>d-subs plugs? I'm thinking of a thumb-screw type thing. Unscrewing
>those tiny screws in the close confines of a completed airplane (and
>them dropping them) doesn't sound like fun. Thumb screws that would
>work with or without d-sub hoods/shells would be ideal.
See bottom of page at
http://dkc3.digikey.com/pdf/T041/0140.pdf
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: ?punch for Carling? |
>
>
>Gentlemen,
>
>I thought of another possibility during the night: I could add a doubler to
>the panel in the area of the switches. The locking holes could be drilled
>all the way through the doubler before the doubler is riveted to the panel.
>Bob's solution using the modified drill bit is pretty slick too!
How do you plan to label the switches? I usually drill the
anti-rotation holes all the way through the panel because
they're covered up the engraved switch panel.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: 912s Capacitor |
>
>I have had both left and right Aeroflash power supplies go bad in less than
>100 hours in service. My Falcon turn coordinator is not spinning up even
>though
>the flag is not displayed.
>My other systems are working perfectly. I am using Bob's wiring design
>w/crowbar. Is it likely my capacitor is bad? I am inclined to think these
>components
>failed on their own but I don't know how to tell. Would a bad capacitor cause
>problems like this? My voltage in flight is steady.
Steady . . . but what is it? Have you checked the voltage
in flight with another voltmeter to confirm calibration
of any voltmeter you may have on the panel. Also, while
looking at DC volts with your multimeter, put it on the
AC volts scale and see what reading you get. Anything over
1.0 volts is reason to investigate further. How old is
the present capacitor?
Bob . . .
________________________________________________________________________________
From: | "Phil Birkelbach" <phil(at)petrasoft.net> |
Subject: | Re: Weird LED fuse behavior |
I have not seen this happen with any automotive fuses, but we use a lot of
GMA fuses offshore for the control systems. Recently on a startup in the
Gulf we had a whole batch of fuses that seemed to be made from resistive
material. They weren't blown and they weren't good either. It was like
having a resister in the line. Very strange. Now that I think about it
though they didn't light up the little LED indicators either, that was what
had us so confused. If they had illuminated the LED then we would never had
measured the fuse with an ohmmeter.
Sorry if I confused the situation. This is just another item in a long list
of reasons why I don't like 'blown-fuse' indicators.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Baffles / Cowling
http://www.myrv7.com
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Weird LED fuse behavior
>
> >
> >
> >I have seen some fuses lately that had some resistance in them. If there
is
> >any resistance in the fuse the LED will glow. Try replacing the fuse and
> >see if that helps.
> >
> >Godspeed,
>
> I'm mystified by this symptom. Red LEDs take about 2 volts
> to get any light out of them. There's no fuse that should
> have a 2 volt drop across it without being blown open.
>
> Bob . . .
>
>
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Battery dumps |
>
>Thanks for your support. I am fine, just see no need to spend thousands on
>brand name equipment that may/may not meet DO-160. Also ever try to find out
>just what the equipment really was tested to; say from King etc etc. Best
>of luck truing to get that info from most any mfgr. Statements meeting
>DO-160 or other \specs seldom are informative as which parts etc were met
>and which parts were not tested or was it all engineering and no testing.
Shouldn't be a problem. Every manufacturer that has taken
the trouble to adopt and comply with DO-160 testing usually
labeles their products to that effect. Our DO-160 qualified
products at Electromech had a line on the label that looked
something like:
DO-160 Env Cat. A2WBABSWLXXXXXXAAAAVWPLB3D4XXXA
Each of those characters in the line represent on of the
DO-160 tests. The value of the character may speak to the
level of stress applied during testing. An X in any slot
says testing was not done in that category. King Radio
puts the DO-160 test spread in their installation manuals.
Even if not published, I cannot imagine anyone taking trouble
to do testing and not willingly taking credit for it over the
phone. If they're reluctant to share such data, it's more
likely that the testing was never done or test results
were disappointing than for testing to have been accomplished
as a "company secrete". If it's a "secret" then it's an answer
they don't want spread around.
>As far as DO-160 I do not know if it covers the load dump of the current
>discussion and I am waiting for Bob to extract what HV pulse it tests to. As
>an unprotected spike can exceed 50V the test of 20v or 30 v is not adequate
>in my opinion and seems to be related to OVP not load dump protection.
>
>I am working with another person off line that perhaps has a solution that
>will be simple and keep the peak voltage under 20V, At least the potential
>is that good. When the development is done He will be the one to announce as
>its based on his input to the problem.
>
>Expect it to take a month however to complete.
>
>At this point I am waiting for info from Bob on what DO-160 tests to with
>regard to spikes. Also perhaps the test circuit used.
The current DO-160 spike test calls for a 300 volt peak pulse delivered
in 10 microsecond through a 50 ohm source impedance. This spike is easily
filtered off with 10 uF input filter cap.
The DO-160 abnormal surge test of 40v for 100 mS is intended to cover
all expected stresses including load or battery dump.
>We have what the auto industry tests to for load dump.
>
>I wonder if DO-160 even addresses load dump effects on the equipment??
>
>Who can tell, I sure cannot as Buying a copy is not in my budget.
>This is a common problem where Standards are not public and one has to buy
>the standard at manufacturers high prices.
Keep in mind that RTCA is neither a manufacturer nor a regulatory
agency. It's a "club" supported by member dues and sales of documents.
If it were a government agency, a copy would be $20 and the taxpayers
would probably be soaked $500 for the cost of maintaining the
facility and personnel that printed it.
See rtca.org
DO-160 to non-members is $195 in hard copy. Dirt cheap for the
time, trouble, and p-o'ed customers it avoids. The cost of the
document is a pittance compared to the time/effort/dollars spent
on doing the design work and confirmation of results suggested
by DO-160. This isn't an exclusive club but membership and stature
is not easily won. It behooves a member of the OBAM aircraft
supply community to at least be cognizant of DO-160 test levels
and design with them in mind. Much of what is suggested can be
substantially complied with by design and without formal testing.
Bob . . .
________________________________________________________________________________
Subject: | ELT Antenna With Floats |
From: | Don Boardman <dboardm3(at)twcny.rr.com> |
Hi all,
I am mounting the short ELT antenna on the belly of my metal Moose.
It's center line is a bit cluttered with push pulls, cables etc. I would
like to mount it about a foot off center.
My question concerns the 3500 amphib Aerocet fiberglass floats sitting under
the airplane. Do floats "block" the signal to and from the antenna? My guess
is that aluminum floats would. What about ones made of fiberglass?
Is there a better option for mounting an ELT antenna given floats?
Thanks,
Don B.
________________________________________________________________________________
From: | "Dan Checkoway" <dan(at)rvproject.com> |
Subject: | Re: Toggle Switches |
> >The majority of the toggle switches that I purchased came without
> >anti-rotation washers. I have looked in several catalogs (Newark, etc.)
and
> >can not find them listed separately. Can one of you guys tell me where I
> >can buy anti-rotation washers separately?
>
> B&C Specialy Products. E-mail Todd at mailto:todd(at)bandc.biz or call
> them at 316.283.8000. They don't show as separate items in their
> catalog but I think they'll make them available to you.
I've heard people say that B&C sometimes forgets they carry 'em. 8-)
They're p/n S700LW in case that happens to you.
)_( Dan
RV-7 N714D
http://www.rvproject.com
________________________________________________________________________________
From: | "Larry Bowen" <Larry(at)BowenAero.com> |
Subject: | ?punch for Carling? |
I drilled those holes all the way through, in the panel and console.
You can't even notice them once the washer is in place unless you are
right up on them.
-
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
> -----Original Message-----
> >
> >
> >Gentlemen,
> >
> >I thought of another possibility during the night: I could add a
> >doubler to the panel in the area of the switches. The locking holes
> >could be drilled all the way through the doubler before the
> doubler is
> >riveted to the panel. Bob's solution using the modified drill bit is
> >pretty slick too!
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Falcon Turn Coordinator |
>
>This is a common problem as I learned. My first one quit within the
>warranty period. The second one worked just beyond that. I inquired at
>Falcon where I could send it or if it was even worth repairing given the
>apparent service life. The response was essentially that the brushes gum up
>and they promised to send cleaning instructions. I never got that
>particular post, but it is easy to do. The case is opened by removing one
>screw. There is an O-ring seal between the outer case and the inner, so it
>is a bit of a chore to get the case removal started. Once inside the
>brushes can be removed by removing a clip - I don't remember exactly how it
>is configured. I cleaned the commutator with a little crocus cloth and
>swabbed it out with a little denatured alcohol on a Q-tip and it has worked
>this time longer than both previous times together.
Interesting. Touching a commutator . . . particularly a fine-motor
commutator with anything other than cleaning solvent and soft wipe
will put microgrooves in the copper surface that will degrade brush
life. In a motor shop, commutators are finished on a lathe with a
diamond tool to re-cut the surface.
In your case, where there is contamination of the brush/comm
interface, perhaps some abrasive effects are beneficial. What
may be happening here is an exchange of poor performance due
to dirt or poor brush selection in trade for shorter brush
life. It will be interesting to see how long it runs this
time and what the next failure mode will be.
Interesting data points Lowell, thanks for sharing them
with us!
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Sky-Tec starter |
>
>
>Bob Nuckells,
>you wrote: "If getting the best starter wasn't an option for me, then adding
>the run-on eliminator would be a good idea."
>
>OK. When I bought the DemarsAero IO360B1E (several years ago), Demars
>suggested the Sky-Tec starter for it's lightness. At the time I knew
>NOTHING about starters except that they are expensive and they sometimes
>break. I've spent most of the last several days studying your book and the
>AeroElectric discussion group archives. I've read several of your posts in
>which you discuss the run-on problem of the PM starters and the high inrush
>current, which could even drop the system voltage to the point that the EI
>wouldn't fire. WOW! The Sky-Tec starter sounds awful!
Not awful, it just has unique characteristics that require
thoughtful system integration. Alternators were a great improvement
over generators but the worked differently (the split rocker master
switch was born, ov protection was standard, etc). The Sky-Tec
is head and shoulders above the Prestolite pig for overall performance
but he has characteristics that make it less friendly to other
systems and components when compared with the wound field starter
like B&C.
> How do they stay in
>business? Anyway, you've offered fixes like the buffer relay to prevent
>run-on and a second battery so the engine can start on one while the EI is
>powered from the other. I could deal with the buffer relay, but having to
>add a second battery just to keep the EI firing seems ridiculous.
Agreed. Hit the starter button and let the engine run a couple
of blades before you turn the ignition switch on. I'll bet this
covers you.
> What
>happens when the two batteries are connected to assist cold-weather
>starting? Bottom Line: Do I need to try to sell the Sky-Tec starter and
>buy a B&C starter?
Not necessarily. Run the Sky-Tec and see what happens. If
the design tweaks and work-arounds do the job, then get your
money's worth out of it. When and if it becomes necessary
to replace the Sky-Tec, consider the B&C and decide wether
friendlier installation and operational characteristics
are worth the extra dollars. Too many decisions are made
on dollars alone . . . when ALL the data is known and
your own goals are factored in, perhaps the higher priced
starter is not as "expensive" as you might have originally
perceived.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> just add SD-8 |
Subject: | Re: "mother of all electric systems" or |
just add SD-8
just add SD-8
>
>
>Bob Nuckolls,
>
>First, I apologize! I've just realized I've been mis-spelling your name.
>In reading your book, I discovered the Fig's 17-5 and Z-14 dual battery,
>dual alternator, split bus "mother of all electrical systems" design. The
>clever name you've given this plan sounds like high praise to me. I assumed
>that meant that's what I, as a serious pilot, should do. But I've since
>come across more of your writings, particularly messages 3573, 3865, 2539,
>3160, 4090 (and probably several others I haven't found yet) which all sound
>like you really think the "all electric airplane on a budget" architecture
>shown in Z-13 is very adequate and possibly preferable.
That's my personal favorite.
> It's certainly
>lighter.
and much less expensive
> As I've mentioned before I have the IO360 Lycoming with dual
>ElectroAir EI and normal compression, and an all-electric (but not too
>power-hungry) IFR panel. I thought I had decided to proceed with the
>"mother of all...." plan, but if you think the "all electric on a budget"
>plan is sufficient, that's what I'll do. Anxiously awaiting your reply to
>this and the PM starter question
Sorry for the delay. too many trips, so little time. If
your compliment of hardware were going into my airplane,
Z-13 would be my choice. Given that you have two engine
driven power sources, I'm not sure I'd bother with a second
battery even with dual electronic ignition. If you do
experience main alternator failure, fly on one of the two
ignitions as a load reduction measure
Bob . . .
________________________________________________________________________________
Subject: | Re: ?punch for Carling? |
From: | John Schroeder <jschroeder(at)perigee.net> |
Bob Nuckolls also has a very nice paper on mounting switches using a
spotfacer and a modified #30 drill. I believe it is on his website. It is
articles/switchmounting/switchmounting.html
Cheers,
John
wrote:
>
>
>>
>>
>> Insert tab washer from the back of the panel with the tab facing the
>> panel back. Pull the switch forward to set and hold the tab against the
>> panel back. Rotate the switch +/- 90 degrees. You have now made a scribe
>> mark on the panel back with the tab. Drill hole halfway through the
>> panel, from the back, on the scribe line. Done.
>>
>> Or you can buy a key punch. Expensive $100 +.
>>
>> Bruce
>> www.glasair.org
>
> Another technique I've used is to cut the peripheral
> tab completely off the keying washer. Coat one side
> with thin coat of E6000 or ShoeGoo cement. Assemble
> switch on panel with keying washer on back side, glued
> face to the panel. Wait 24 hours before disassembly.
>
> This genre' of cements does a good job of bonding
> the keying washer to an aluminum panel. There is
> slight risk of some squish-out glue getting into
> switch mounting threads. It's only a slight impediment
> to future disassembly and may be easily trimmed away
> with an Xacto knife later.
>
> Bob . . .
>
>
--
________________________________________________________________________________
From: | "Eric M. Jones" <emjones(at)charter.net> |
Subject: | World's easiest question... |
Okay, so how do I remove solder flux? In the easiest, greenest, way....? Is
there some secret?
Eric
________________________________________________________________________________
From: | "David Swartzendruber" <dswartzendruber(at)earthlink.net> |
Subject: | World's easiest question... |
Use water soluable flux and then flush with water.
Dave
>
>
> Okay, so how do I remove solder flux? In the easiest, greenest,
way....?
> Is
> there some secret?
>
> Eric
>
________________________________________________________________________________
From: | "John Slade" <sladerj(at)bellsouth.net> |
Subject: | Weird LED fuse behavior |
Thanks for all the input on the glowing fuse.
I replaced it with another fuse (same type) and the problem went away. I'm
guessing at a fault within the fuse itself.
Regards,
John Slade
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | World's easiest question... |
Water soluble is good. If you're using more resistant
fluxes, try this: I buy cans of carburetor cleaner from
Walmart. The really cheap stuff is about 90 cents a can.
The liquid is basically lacquer thinner. The spray
is powerful enough to do a quick job of cleaning up.
One caveat, some plastics may not like the cleaner but
this is rare in electronics parts. I wash with the carb
cleaner and then blow dry with a heat gun set on low
heat. Your finished surfaces are ready for conformal
coating.
Bob . . .
>
>
>Use water soluable flux and then flush with water.
>
>Dave
>
> >
> >
> > Okay, so how do I remove solder flux? In the easiest, greenest,
>way....?
> > Is
> > there some secret?
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | ?punch for Carling? |
>
>I drilled those holes all the way through, in the panel and console.
>You can't even notice them once the washer is in place unless you are
>right up on them.
Washers on the pilot side of the panel? I usually put them on the
switch side and use a thin, flat washer on the front to keep from scratching
the panel with my nut-driver.
Bob . . .
________________________________________________________________________________
From: | "Terry Watson" <terry(at)tcwatson.com> |
Subject: | ELT Antenna With Floats |
Don,
If you mean the transponder antenna, maybe inside the fiberglass floats
would be a good location. Glass airplane builders and RV builders with
fiberglass wingtips often mount antennas inside. As someone else pointed
out, maybe the ELT antenna belongs on top.
Terry
Hi all,
I am mounting the short ELT antenna on the belly of my metal Moose.
It's center line is a bit cluttered with push pulls, cables etc. I would
like to mount it about a foot off center.
My question concerns the 3500 amphib Aerocet fiberglass floats sitting under
the airplane. Do floats "block" the signal to and from the antenna? My guess
is that aluminum floats would. What about ones made of fiberglass?
Is there a better option for mounting an ELT antenna given floats?
Thanks,
Don B.
________________________________________________________________________________
From: | Chad Robinson <crobinson(at)rfgonline.com> |
Subject: | Re: World's easiest question... |
Eric M. Jones wrote:
>
> Okay, so how do I remove solder flux? In the easiest, greenest, way....? Is
> there some secret?
With flux remover. =) Seriously, rubbing alcohol works to some degree, and I
use it a lot on circuit boards with water-soluble flux but not all flux is
water-soluble. Most electronics supply houses carry flux remover that will do
the job. I get mine from Digikey or Circuit Specialists. If you are picking
the flux yourself use water-soluble and it'll save you trouble. But most
resin-core solders have flux that is NOT water-soluble, so keeping remover on
hand is a good idea.
In terms of being green, well, you could always leave it in a trash-destined
glass jar, wait a LONG time for the stuff to just evaporate, then throw the
jar and residue out. But most of these flux removers are just alcohol-based
solvents so they can be safely flushed down the drain. They're certainly much
better for the environment than etchant...
Regards,
Chad
________________________________________________________________________________
From: | "Larry Bowen" <Larry(at)BowenAero.com> |
Subject: | ?punch for Carling? |
Yes, on the pilot side of the panel. My switches didn't come with any
flat washers. I don't/didn't know any better, and I think they look
good. And I won't let this line of questioning lead to doubt and
re-installation of said switches.... :)
-
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
> -----Original Message-----
> From: Robert L. Nuckolls, III [mailto:bob.nuckolls(at)cox.net]
> Sent: Tuesday, March 02, 2004 2:48 PM
> To: aeroelectric-list(at)matronics.com
> Subject: RE: AeroElectric-List: ?punch for Carling?
>
>
> -->
>
> >-->
> >
> >I drilled those holes all the way through, in the panel and console.
> >You can't even notice them once the washer is in place
> unless you are
> >right up on them.
>
> Washers on the pilot side of the panel? I usually put them on the
> switch side and use a thin, flat washer on the front to
> keep from scratching
> the panel with my nut-driver.
>
> Bob . . .
>
>
> ============
> Matronics Forums.
> ============
> ============
> http://www.matronics.com/FAQ/AeroElectric-List.htm
> Search Engine: http://www.matronics.com/search
> ============
>
>
>
>
>
>
________________________________________________________________________________
From: | Charlie Kuss <chaskuss(at)bellsouth.net> |
Subject: | Re: Toggle Switches |
Vince,
Carling Technologies has them listed in their catalog. See
http://www.carlingtech.com/pdf/s_bushng.pdf
They are on the lower right side of page 69
B&C or your local Carling distributor can get them for you.
Charlie Kuss
>
>The majority of the toggle switches that I purchased came without
>anti-rotation washers. I have looked in several catalogs (Newark, etc.) and
>can not find them listed separately. Can one of you guys tell me where I
>can buy anti-rotation washers separately?
>
>Vince Welch
>
>Find things fast with the new MSN Toolbar includes FREE pop-up blocking!
>http://clk.atdmt.com/AVE/go/onm00200414ave/direct/01/
>
>
________________________________________________________________________________
Subject: | interesting resource re aviation survival |
From: | "Scott, Ian" <ian_scott(at)commander.com> |
http://www.equipped.com/avsrvtoc.htm
----------------------------------------------------
Visit http://www.commander.com
This message is for the named person's use only.
Privileged/confidential information may be contained in
this message. If you are not the addressee indicated in
this message (or responsible for delivery of the message
to such person), you may not copy or deliver this
message to anyone. In such case, you should destroy
this message, and notify us immediately.
Any views expressed in this message are those of the
individual sender, except where the message states
otherwise and the sender is authorised to state them to
be the views of any such entity.
----------------------------------------------------
________________________________________________________________________________
From: | "Wesley T Robinson" <wesleyt(at)stanfordfurniture.com> |
Subject: | ?punch for Carling? |
There is no username, just a password.
Wesley T Robinson
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Robert L. Nuckolls, III
Subject: Re: AeroElectric-List: ?punch for Carling?
>
>
>Gentlemen,
>
>I thought of another possibility during the night: I could add a
doubler to
>the panel in the area of the switches. The locking holes could be
drilled
>all the way through the doubler before the doubler is riveted to the
panel.
>Bob's solution using the modified drill bit is pretty slick too!
How do you plan to label the switches? I usually drill the
anti-rotation holes all the way through the panel because
they're covered up the engraved switch panel.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
==
==
==
==
---
Incoming mail is certified Virus Free.
---
________________________________________________________________________________
From: | "David Swartzendruber" <dswartzendruber(at)earthlink.net> (by way of Matt Dralle |
)
(by way of Matt Dralle )
A while back, the subject of some new fuseholders from Bussmann came up.
The unique feature of these fuseholders is that they mount through a panel
with all the wires behind, and fuse access in front. B&C chose to not add
these to their product line so I volunteered to do so.
If you are interested in this fuseholder, you will find more information at
www.mihdirect.biz where they are also available for purchase. Two members
of this list, Charlie Kuss and Kingsley Hurst, have already purchased these
fuseholders and I'm sure they would be willing to give their evaluation if
asked. Bob has also had a chance to see one.
Dave Swartzendruber
________________________________________________________________________________
From: | "bryan hooks" <hook3607(at)bellsouth.net> |
Subject: | Re: Runaway stab trim prevention |
Been off the list for a couple of bit.
Sorry to have caused such an issue 'bout the runaway stab trim thing.
Glad to hear that full trim at cruise is not that big a deal. I just
posed the question for two reasons: (1) I don't have any RV experience
yet and didn't know that it was really a non-event, and (2) the airplane
I fly at work can kill you (and actually has) if the trim runs away.and
that's with a stab trim cut-out switch within reach of both pilots. Now
don't get me wrong, I never believed this would be a BIG problem in an
RV, but I thought it could be an irritating event that might be
prevented if there was something that could be done easily and cheaply
to prevent it. Maybe I'll just remember where that ole trim circuit
breaker is located.
Bryan Hooks
RV7A, slow
Knoxville, TN
Hook3607(at)bellsouth.net
________________________________________________________________________________
Subject: | FW: Grounding Power outlets |
From: | Don Boardman <dboardm3(at)twcny.rr.com> |
Hi Bob and All,
I am installing a power outlet (Cigar lighter) at each of the four seating
areas in my Moose. As I was running wire today and intending on bringing the
ground for the units back to the panel ground block I realized that the
units were also grounded via the airframe because of there construction.
What course of action is best?
Simply use the airframes local ground.
Leave the unit grounded to the airframe and also run the ground wire to the
PNL ground.
Manage to insulate the body of the unit from the airframe (a pain) and run a
ground wire to the PNL ground.
Thanks,
Don B.
________________________________________________________________________________
From: | "Rob W M Shipley" <rob(at)robsglass.com> |
Subject: | Avionics design robustness |
Bob wrote
Years ago, I published a list of questions that folks could
paste to a note-card and carry around during their visits to
the various booths at OSH and elsewhere. The questions had to
do with information gathering about the manufacturer's awareness
and willingness to apply any level of environmental robustness
to his/her products. Whether or not DO-160 was embraced
was immaterial. The point was that EVERY manufacturer should
be aware of a degree of consumer concerns about such matters and
find it to be in their own best interests to address those concerns.
This is exactly how the free market is supposed to work and WILL
if we properly exercise our prerogatives as knowledgeable,
responsible consumers.
This advice came a few seconds after I had emailed Michael Coates at XCOM in Australia
to find out if this newer and presumably technologically more developed
successor to the Microair has better protection for voltage excursions.
I'll copy his reply to the list since this navcom appears to be a promising newcomer.
Rob
Rob W M Shipley
N919RV (res) Fuselage .....still!
________________________________________________________________________________
From: | Dabusmith(at)aol.com |
Subject: | Re: Turn coordinator |
>> Touching a commutator . . . particularly a fine-motor
commutator with anything other than cleaning solvent and soft wipe
will put microgrooves in the copper surface that will degrade brush
life.
That is lucky for me. I cleaned mine with rubbing alcohol and Q-tip. It is
working normal again. I didn't have any fine abrasive handy. Grateful for the
info.
Dave Smith
Graham WA.
________________________________________________________________________________
From: | "Ned Thomas" <315(at)cox.net> |
Subject: | Re: Turn coordinator |
I took the "Ford" alternator out of my spam can to a local alternator repair
shop. I watched him"clean" the commutator. When he first put it on the
lathe I thought this was great, he would clean it up and make it truly
round. I was shocked when he picked up some emory cloth turned on the lathe
and used the cloth to "clean" the commutator. Said that's standard industry
practice, how he's done it for 30yrs...
He only charged me a couple dollars for the new brushes and "cleaning" and
told me it should outlast my airboat...:)
----- Original Message -----
From: <Dabusmith(at)aol.com>
Subject: AeroElectric-List: Re: Turn coordinator
>
> >> Touching a commutator . . . particularly a fine-motor
> commutator with anything other than cleaning solvent and soft wipe
> will put microgrooves in the copper surface that will degrade brush
> life.
>
> That is lucky for me. I cleaned mine with rubbing alcohol and Q-tip. It is
> working normal again. I didn't have any fine abrasive handy. Grateful for
the
> info.
>
> Dave Smith
> Graham WA.
>
>
________________________________________________________________________________
From: | "Paul Messinger" <paulm(at)olypen.com> |
Subject: | Re: Battery dumps |
>
> The current DO-160 spike test calls for a 300 volt peak pulse delivered
> in 10 microsecond through a 50 ohm source impedance. This spike is
easily
> filtered off with 10 uF input filter cap.
>
> The DO-160 abnormal surge test of 40v for 100 mS is intended to cover
> all expected stresses including load or battery dump.
The spike test needs to include rise time. If the rise time is fast enough,
a 10MFD electrolytic may have a sufficiently high internal series resistance
to act more like a resistor than a cap.
So, while 10 mfd may be sufficient, just any 10 mfd cap may not be.In the
aerospace world we used a tantalum cap along with a much smaller HV cap to
catch the fast spikes.
The load dump case of 40V for 100 MS is both lower V and shorter duration
than specified for automotive load dump suppression devices.
I intend to test various load dump currents from 10 to at least 40 amps in
sudden load reduction along with 0 thru 20 amps non dumped load (the
electrical system)
I have not heard of 40V and 100 ms being something avionics are designed to
withstand. That sure is much harder to design to than a simple input cap.
If the load dump is the result of the battery contactor opening the
alternator "B" lead is still connected to the main bus of the aircraft and
the load dump spike is passed on to the rest of the acft electronics. The
bus voltage will rise until it supports the peak dump current and that can
be shorted components. This applies to both internal and external
regulators.
I hope to test and suggest a solution to two different concerns.
First protection of the alternator regulator from a load dump. Appears to be
fairly simple At least to keep the pulse under 40v.
The second concern is where the battery is being charged and is suddenly
disconnected but the "B" lead is still connected to the main bus. Also the
objective is to keep the peak voyage under 30 V and ideally under 20 V.
There is a design being considered that may accomplish that is simple and
thus low cost.
As I have mentioned in a past post I am working with another electronics
expert off line and the results will be posted when there is real data to be
shown.
Thus its time to go silent for a while and spend the resulting time working.
Paul
________________________________________________________________________________
From: | Kevin Horton <khorton01(at)rogers.com> |
Subject: | Re: Runaway stab trim prevention |
>
>
>Been off the list for a couple of bit.
>
>Sorry to have caused such an issue 'bout the runaway stab trim thing.
>Glad to hear that full trim at cruise is not that big a deal. I just
>posed the question for two reasons: (1) I don't have any RV experience
>yet and didn't know that it was really a non-event, and (2) the airplane
>I fly at work can kill you (and actually has) if the trim runs away.and
>that's with a stab trim cut-out switch within reach of both pilots. Now
>don't get me wrong, I never believed this would be a BIG problem in an
>RV, but I thought it could be an irritating event that might be
>prevented if there was something that could be done easily and cheaply
>to prevent it. Maybe I'll just remember where that ole trim circuit
>breaker is located.
>
>Bryan Hooks
>RV7A, slow
Well, runaway trim is quite different depending on whether the
aircraft has stab trim (i.e. the angle of incidence of the stab is
changed by the trim system) or an elevator trim tab. Stab trim
runaways can be very dangerous, as you can get in a situation where
you no longer have enough pitch authority in one direction. The
elevator may simply not be big enough to counter the pitching moment
created by the stab which has gone full travel.
If we have elevator trim tabs, like on your RV-7A, then we don't have
a problem of pitch authority. The only questions are how high the
stick force will be. But if you apply enough stick force you will
always be able to get enough pitch authority. In general, people who
have flight tested RVs to see the effect of trim runaways have
reported high, but manageable stick forces at high speed. The stick
forces lighten up as you slow down. Depending on how fast your trim
servo moves, it could get a bit exciting for a few seconds while you
figure out what is going on.
I've got a Matronics Speed Governor to slow my trim down, to give me
a bit more time to react. I've also got a button on my stick that
will kill power to the trim and wing leveler servos if I hold it
down. I can then reach over and turn off the trim power on the side
console.
So, if we are talking about RVs, don't talk about stab trim runaways,
as they don't exist, unless you have made a major design change.
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
________________________________________________________________________________
From: | "C J Heitman" <cjh(at)execpc.com> |
Bob,
I had the same problem as Ted with the RCT-3 crimper. Mine actually cut
several pins into 2 pieces when attempting to make crimps. I got the pins
from B&C as well as the tool so I'm quite sure I was using the correct
combination of pins and crimper. I didn't have very many pins to do, so I
just soldered them and made sure that I had a good strain relief on the
wires. On my RCT-3 crimper, the 4 crimping "pins" in the tool touch each
other before the ratchet mechanism will allow the tool to open. Is there an
adjustment for stroke length on this crimper?
Chris Heitman
Dousman WI
RV-9A N94ME
http://my.execpc.com/~cjh/rv9a.html
-----Original Message-----
>
>We purchased several crimpers from B&C and included was the RCT-3. It is
>supposed to be for the D sub pins but when you start clamping down on the
>pin, you can't release it until you have squeezed all of the way down
>and that just about ruins the pin. By the time you can release it the
>opening is really small I have used the hex crimper using the .043 slot
>which seems to work alright.
I am mystified by your comments. The RCT-3 tool IS for machined
D-sub pins and we've sold hundreds of these tools. I give away
a half dozen or so at each weekend seminar. I've not seen or
heard of the problem you describe.
Here's a d-sub pin I just installed with an RCT-3 from my
own toolbox:
http://www.aeroelectric.com/Pictures/RCT-3_Male.jpg
---
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Communtator and slip ring finishing practices |
>
>I took the "Ford" alternator out of my spam can to a local alternator repair
>shop. I watched him"clean" the commutator. When he first put it on the
>lathe I thought this was great, he would clean it up and make it truly
>round. I was shocked when he picked up some emory cloth turned on the lathe
>and used the cloth to "clean" the commutator. Said that's standard industry
>practice, how he's done it for 30yrs...
>
>He only charged me a couple dollars for the new brushes and "cleaning" and
>told me it should outlast my airboat...:)
Interesting. I'll run that by my friends out at
Electromech to see if there are any new thoughts
about it. It's been more than 20 years since I
worked there.
Did a little poking around on the 'net and found
this page that speaks to sheet abrasives:
http://www.michaelholigan.com/Departments/HowTo/HowToPage.asp?ts_id=abrasive
I note that "crocus cloth" as a very fine grit
only. Any machining activity that removes metal
is a cutting action. Smoothness of the final
finish is a function of how small the cuts are.
Jewelers rouge is used to produce a high polish
on metals but must be in fact, an abrasive of
exceedingly small size. The "scratches" it leaves
behind are so closely spaced that rays of light
impinging upon the surface are reflected with
minimal scatter. This means that spacing of
the "scratches" are small with respect to
wavelength of light.
It may be that your friend in the overhaul shop
has identified an acquired a cloth with very
fine grit that produces a polish with finer
striations than his lath tool bit . . . if so,
his practice may have some value commensurate with
his perceptions.
I'll ask around.
Bob . . .
________________________________________________________________________________
From: | "Cy Galley" <cgalley(at)qcbc.org> |
Subject: | Re: Turn coordinator |
Big difference between the commutator on a generator, even an alternator and
the commutator on a very tiny high speed dc-motor on a turn coordinator.
Brushes on the automotive gen and alt are very massive and are designed to
work in a hostile environment. The TC on the other hand a very small and
live in a semi-sealed situation where dirt and loose particles are a big
problem. As one of us it prone to say... "It all depends!"
Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh
Editor, EAA Safety Programs
cgalley(at)qcbc.org or sportpilot(at)eaa.org
Always looking for articles for Sport Pilot
----- Original Message -----
From: "Ned Thomas" <315(at)cox.net>
Subject: Re: AeroElectric-List: Re: Turn coordinator
>
> I took the "Ford" alternator out of my spam can to a local alternator
repair
> shop. I watched him"clean" the commutator. When he first put it on the
> lathe I thought this was great, he would clean it up and make it truly
> round. I was shocked when he picked up some emory cloth turned on the
lathe
> and used the cloth to "clean" the commutator. Said that's standard
industry
> practice, how he's done it for 30yrs...
>
> He only charged me a couple dollars for the new brushes and "cleaning" and
> told me it should outlast my airboat...:)
>
>
> ----- Original Message -----
> From: <Dabusmith(at)aol.com>
> To:
> Subject: AeroElectric-List: Re: Turn coordinator
>
>
> >
> > >> Touching a commutator . . . particularly a fine-motor
> > commutator with anything other than cleaning solvent and soft wipe
> > will put microgrooves in the copper surface that will degrade brush
> > life.
> >
> > That is lucky for me. I cleaned mine with rubbing alcohol and Q-tip. It
is
> > working normal again. I didn't have any fine abrasive handy. Grateful
for
> the
> > info.
> >
> > Dave Smith
> > Graham WA.
> >
> >
>
>
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: FW: Grounding Power outlets |
>
>Hi Bob and All,
>
>I am installing a power outlet (Cigar lighter) at each of the four seating
>areas in my Moose. As I was running wire today and intending on bringing the
>ground for the units back to the panel ground block I realized that the
>units were also grounded via the airframe because of there construction.
>
>What course of action is best?
>
>Simply use the airframes local ground.
>
>Leave the unit grounded to the airframe and also run the ground wire to the
>PNL ground.
>
>Manage to insulate the body of the unit from the airframe (a pain) and run a
>ground wire to the PNL ground.
I presume you plan to offer these outlets to passengers
for use of automotive power adapters for personal electronics.
These devices are not strong antagonist. Further, the standard
bus noises are going to be stronger than any ground-loop
generated noises so local grounding will be fine.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Bob,
>
>I had the same problem as Ted with the RCT-3 crimper. Mine actually cut
>several pins into 2 pieces when attempting to make crimps. I got the pins
>from B&C as well as the tool so I'm quite sure I was using the correct
>combination of pins and crimper. I didn't have very many pins to do, so I
>just soldered them and made sure that I had a good strain relief on the
>wires. On my RCT-3 crimper, the 4 crimping "pins" in the tool touch each
>other before the ratchet mechanism will allow the tool to open. Is there an
>adjustment for stroke length on this crimper?
No, it's preset. You should contact B&C about these tools. I'll
have some conversation with them too. It appears that there may
be some production variation in the die strokes that needs to
be inspected. This is easy to do with a go/no-go gage (close the
tool on a specific size drill or piano wire. It should grab one
size while allowing a smaller one to slip free.
It may be that B&C needs to do receiving inspection on the tools.
This is the first I've hard of problems with this tool I'm
glad you brought it up. It needs to be fixed.
Bob . . .
________________________________________________________________________________
From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
Subject: | Re: Battery dumps |
>
>
>
> >
> > The current DO-160 spike test calls for a 300 volt peak pulse delivered
> > in 10 microsecond through a 50 ohm source impedance. This spike is
>easily
> > filtered off with 10 uF input filter cap.
> >
> > The DO-160 abnormal surge test of 40v for 100 mS is intended to cover
> > all expected stresses including load or battery dump.
>
>The spike test needs to include rise time. If the rise time is fast enough,
>a 10MFD electrolytic may have a sufficiently high internal series resistance
>to act more like a resistor than a cap.
>
>So, while 10 mfd may be sufficient, just any 10 mfd cap may not be.In the
>aerospace world we used a tantalum cap along with a much smaller HV cap to
>catch the fast spikes.
It's 10 uS, half-sine measured at the base. Not exceedingly
fast. A tantalum wiped it out quite effectively.
>The load dump case of 40V for 100 MS is both lower V and shorter duration
>than specified for automotive load dump suppression devices.
Yes. I presume that the RTCA committee researched real
risks on airplanes and arrived at their conclusions based
on 99th percentile stresses + some headroom. Not being
privy to RTCA's deliberations, it seems useful to do
some informative studies of our own. However, given that RTCA
is not a government operation nor does it have any products to
sell, I am less skeptical of RTCA pronouncements than those
of any other body . . . except of course, you and I.
>I intend to test various load dump currents from 10 to at least 40 amps in
>sudden load reduction along with 0 thru 20 amps non dumped load (the
>electrical system)
>
>I have not heard of 40V and 100 ms being something avionics are designed to
>withstand. That sure is much harder to design to than a simple input cap.
>
>If the load dump is the result of the battery contactor opening the
>alternator "B" lead is still connected to the main bus of the aircraft and
>the load dump spike is passed on to the rest of the acft electronics. The
>bus voltage will rise until it supports the peak dump current and that can
>be shorted components. This applies to both internal and external
>regulators.
Sure . . . and it may be that the 40v figure was arrived at
by assuming some minimal steady state load by system
accessories.
>I hope to test and suggest a solution to two different concerns.
>
>First protection of the alternator regulator from a load dump. Appears to be
>fairly simple At least to keep the pulse under 40v.
>
>The second concern is where the battery is being charged and is suddenly
>disconnected but the "B" lead is still connected to the main bus. Also the
>objective is to keep the peak voyage under 30 V and ideally under 20 V.
>There is a design being considered that may accomplish that is simple and
>thus low cost.
That would be great.
>As I have mentioned in a past post I am working with another electronics
>expert off line and the results will be posted when there is real data to be
>shown.
>
>Thus its time to go silent for a while and spend the resulting time working.
Shucks Paul, we're having so much fun. Ya mean we gotta
go off and do some real work? Glad I don't work for you, I'll
bet you're a real pain-in-the-arse around the shop :-)
Lets do some good work!
Bob . . .
________________________________________________________________________________
From: | Charlie Kuss <chaskuss(at)bellsouth.net> |
Subject: | 3 bulb Nav light wiring question |
Bob & Listers,
I was using AutoCAD and Bob's templates last night to sketch out my navigation
light circuit. I will be using 2 Grimes position lamps installed in the wing
tips of my RV-8A. I will also have a white position/strobe lamp (Whelen A500A)
installed in the rear of the rudder tip.
This presents a dilemma. I need to know how much each of these bulbs draw. My
fuzzy memory "thinks" it's around 2-3 amps each. This would mean Appox. 7-10 amps
going through a single 1-3 style switch and fuse. This would necessitate using
18 or even 16 AWG wire throughout the circuit. This circuit has some of the
longest wiring runs on my 8A (to the tail and both wing tips)
With 3 lamps instead of 2, I think I'm going to have to up size the wire above
the 18 AWG shown in Bob's template. I'm ASSuming :-0 that these bulbs have the
same sort of inrush current upon start up that other incandescent bulbs have??
The problem is that I need to size the supply wire between the fuse and the
switch to carry the load of all 3 bulbs.
If I run all three bulbs off of 1 switch and fuse circuit, I'll need to increase
the wire size to each bulb above that which is needed to carry current to that
individual bulb. This would be necessary to insure that these wires would
not overheat before the circuit fuse would blow. I'll have to purchase additional
wire to do this.
I could down size the wire from the switch to each bulb (20AWG) and install a
5 amp fuse between the switch and the output wires. This seems really clunky &
clumsy to me. I prefer to keep all the fuses in the fuse block.
The third option would be to use a 3-2 (triple pole, single throw ON/OFF) style
switch and supply each bulb of the circuit independently of the others. This
would allow use of smaller 20AWG wire (which I already have in various colors).
This would require 3 separate fuses. I'm using 2 of Bussman's new model 15710
ATO style fuse blocks. Because this unit has 20 fuse circuits in the physical
space that the standard 10 fuse unit has, I have enough extra fuse slots to
accommodate this. I'm mounting the main fuse block in my right side mid cabin
cover. The wire run from the fuse block to all my lighting switches will be less
than 15 inches, so the weight of the 2 extra supply wires is negligible.
I am open to comments and suggestions. Are there any holes in my ideas? Any better
solutions? I have AutoCAD files of this circuit available "off list".
Charlie Kuss
RV-8A wiring
staying up WAY to late at night playing with AutoCAD! :-)
________________________________________________________________________________
Subject: | ELT = Transponder Antenna |
From: | Don Boardman <dboardm3(at)twcny.rr.com> |
Hi Guys,
Thanks for your help and thoughts on ELT antenna location. When I read the
first response that it should be on top, I said to myself, WHAT! I have
never heard of such a thing.
You know after 12 hours in the shop crawling around an airframe and under a
panel I guess my body and mind get a little mushy.
I should have said TRANSPONDER ANTENNA.
I did notice that one person picked up on my mistake, thanks. I am not sure
if the logistics of getting the antenna into the floats is practical.
OK THE ORIGINAL POST WITH TRANSPONDER ANTENNA.
I am mounting the short transponder antenna on the belly of my metal Moose.
It's center line is a bit cluttered with push pulls, cables etc. I would
like to mount it about a foot off center.
My question concerns the 3500 amphib Aerocet fiberglass floats sitting under
the airplane. Do floats "block" the signal to and from the antenna? My guess
is that aluminum floats would. What about ones made of fiberglass?
Is there a better option for mounting an transponder antenna given floats?
Thanks,
Don B.
________________________________________________________________________________
From: | "Lowell Fitt" <lcfitt(at)inreach.com> |
Subject: | Re: Turn coordinator |
I guess, I started this thread and probably should clarify couple of few
things. First the Turn Coordinator in question is a product of China - non
certified. Unfortunately, that should give a hint as to the commutator
finishing process the unit got in the factory. When two units work
approximately 100 hours since new then fail, I believe it suggests a
fundamental problem with the unit. Reinforced when I am essentially brushed
off by the distributor and told that the commutator needs cleaning and I can
do it myself. That sort of suggests to me a volume of service needs that
they don't want to deal with.
Anyway, I did at first as Bob suggests, simply a cleaning with a solvent
being careful to remove all debris from the grooves. It lasted probably 50
hours. When I did it the second time, I used the crocus cloth.
Now this has been a year since I did this, but as I recall the commutator
had circumferential grooves on it and I got the impression that the metal
was soft, as in an annealed state.
I hope this doesn't sound like product bashing as I am quite pleased with
the unit when it is functioning and the cleaning took an hour at best from
panel to panel.
Lowell
----- Original Message -----
From: "Cy Galley" <cgalley(at)qcbc.org>
Subject: Re: AeroElectric-List: Re: Turn coordinator
>
> Big difference between the commutator on a generator, even an alternator
and
> the commutator on a very tiny high speed dc-motor on a turn coordinator.
> Brushes on the automotive gen and alt are very massive and are designed to
> work in a hostile environment. The TC on the other hand a very small and
> live in a semi-sealed situation where dirt and loose particles are a big
> problem. As one of us it prone to say... "It all depends!"
February 24, 2004 - March 03, 2004
AeroElectric-Archive.digest.vol-cy