AeroElectric-Archive.digest.vol-cn
October 13, 2003 - October 23, 2003
>
> ----- Original Message -----
> From: "Trampas" <tstern(at)nc.rr.com>
> Subject: RE: AeroElectric-List: Electronic tacho & mag check
>
>
> >
> > I have heard of people taking a couple of capacitors and connecting them
in
> > series with the P-leads, then connect both leads, after the capacitors,
to
> > the tach. I am not sure how well this would work with your tach.
> >
> > I personally would look for a different system that had the capability to
> > monitor both p-leads all the time and let you know if there is any
> > difference. That is an engine monitor which could notify you in flight of
> > any difference in the RPMs of the left and right mag.
> >
> > I am currently working on building such an engine monitoring system.
> >
> > Trampas
> >
>
>
________________________________________________________________________________
| From: | "Werner Schneider" <wernerschneider(at)compuserve.com> |
| Subject: | Re: List of tools |
Hello Mickey,
you're going the fast lane =(;o), you will get all the electrical tools in
Switzerland, just at a much
higher price =(;o(( (www.distrelec.ch).
You can have a look at http://www.bandcspecialty.com/parts.html I bought
from them the crimp tools, a lot of wire, the toogle buttons, plugs, fastons
and the OV protection module, bus bars etc.
For more details contact me direct.
Before you start electrical wise you should go and design your setup with a
load analysis.
Werner
----- Original Message -----
From: "Mickey Coggins" <mick-matronics(at)rv8.ch>
Subject: AeroElectric-List: List of tools
>
> Hi,
>
> I'm just starting my RV8, and due to my geographically
> challenged location (mountains of Switzerland) I would
> like to buy all the tools, testers, and meters that I
> might for the electrical system of my RV8. I can get
> almost nothing locally, except very simple household
> wiring supplies.
>
> I have purchased the 'Connection, as Bob calls it, and
> am in the process of reading it. I'll be visiting the
> US next week, and I'd like to pick up as much of the
> stuff as I possibly can during this visit. I'll be
> back in the states for Thanksgiving as well, so it's
> not critical that I get everything in this visit.
>
> Does anyone know of a list of tools, and possibly
> suppliers, that I could use? I would much prefer to
> err on the side of having a tool that I will never use
> than to need something and to not have it, and have to
> wait for it to be delivered.
>
> I guess if I don't hear any suggestions I'll just buy
> everything I can find in all the aviation catalogues,
> but that seems a bit wasteful.
>
> Thanks!
> Mickey
>
>
> --
> Mickey Coggins
> http://www.rv8.ch/
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: magneto wiring |
>Below is the result of your inquiry. It was submitted by
>Mitch Faatz (mitchfaatz(at)hotmail.com) on Monday, October 13, 2003 at 00:24:29
>
>Monday, October 13, 2003
>
>Mitch Faatz
>
>,
>Email: mitchfaatz(at)hotmail.com
>Comments/Questions: Bob, bought your Connection book a few years back,
>quick question: Starting an airplane with right mag energized can cause
>kickback, so we start with just left on. What about inflight restart?
The vast majority of airplanes (pushers being the
most notable exceptions) will windmill the prop in
flight. Restarting generally involves restoring fuel
flow and power will resume.
>1) Prop spinning: do you need to re-engage the starter every? If so, can
>kickback occur? I'm guessing not since prop is spinning.
Exactly . . . as long as the engine is still in motion,
all you need to do is get fuel flowing again . . . assuming
of course that you still have usable fuel aboard . . .
>2) Prop stopped: I'm guessing kick-back can occur here.
>
>If kickback can occur even during engine restart, how serious is it?
It can and routinely does break things . . . most notably
starter castings.
> I'm wondering if I should make my Right mag toggle disable the starter
> circuit.
Why not?
> Your suggestion in Append-Z to have left mag also with momentary
> starter won't work in my case because I want a starter button on my
> stick. I'll have a separate 'starter' toggle with switch guard:
> off=down, center=stick button enabled, up=engage starter. Dropping
> switch guard will move back to started disabled.
That's fine, but unless you have an impulse coupled
right mag, I'd disable the starter control circuit
while the right mag is ON. If you were using the
traditional off-l-r-both-start keyswitch, there
would be a jumper installed to effect this control
philosophy and it too has no way of differentiating
whether the cranking operation is in flight or
on the ground.
I will invite you to join us on the AeroElectric List
to continue this and similar discussions. It's useful to
share the information with as many folks as possible.
A further benefit can be realized with membership on
the list. There are lots of technically capable folks
on the list who can offer suggestions too. You can
join at . . .
http://www.matronics.com/subscribe/
Well considered and technically elegant answers to
all of your questions are waiting for you there. Also,
check out the downloadable materials at
http://www.aeroelectric.com
Thanks!
Bob . . .
|---------------------------------------------------|
| A lie can travel half way around the world while |
| the truth is till putting on its shoes . . . |
| -Mark Twain- |
|---------------------------------------------------|
________________________________________________________________________________
| From: | MikeM <mladejov(at)ced.utah.edu> |
| Subject: | Re: AeroElectric-List Digest: 14 Msgs - 10/10/03 |
Get a metal aircraft!
Seriously, it sounds like your transmitting antenna has a poor
ground plane and/or the Standing Wave Ratio of the antenna is
high. High SWR causes r.f. current to flow along the sheild of
the antenna coax, and then it spreads out and flows along every
piece of wiring in the entire aircraft, including the headset
wiring (all of it becomes part of the ground-plane the antenna
should have had...)
Put a decent ground-plane under the antenna, and your problems
will magically disappear...
Mike M.
>
> In my aircraft, when I transmit on my comm radio, I hear a loud squeal in
> my headset. The avionics shop said it's due to the close proximity of the
> antenna to my headset, and the wire that goes across from one side of the
> headset to the other picks up the signal. The airplane is all wood, and
> the antenna is behind the back seat, inside the fuselage.
> Is there anything that can be done to get rid of this annoying noise?
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Alternator Noise in Headset |
>
><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> You're a gentleman and a scholar and I apologize for my
> impatience.
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Not a problem sir. BTW, you might consider trimming your
replies to throw out sections of the previous post that
do not add to the continuity of the conversation. This keeps
posts reasonably short and easier to read.
>If the noise is present with the alternator OFF, then I don't
>see how this system can be involved. Does the tone vary in pitch
>with engine rpm . . . alternator generated noises do vary in pitch
>with rpm and they go away when the alternator is turned off.
><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> I'll have to check that on the next flight.
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
High pitched whines come from three common antagonists
in aircraft . . . alternators, strobe power supplies and
some motors. In every case, shutting the suspect system
OFF kills the noise. Strobe and Alternator noise are distinctive
in their variable pitch (one with rpm, the other with each
firing of the strobe system).
>Do you hear the noise whether or not there is a radio
>transmission being received?
>
><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> Yes, the noise was overlaid on received radio transmissions.
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
This is an important clue. This means the radios
are not involved which means further that the
noise is not an radiated RF propagation mode. Noise
gets into audio systems mostly by conduction . . . i.e.
poor grounding techniques and/or conducted into the
system via the +14v bus supply.
>I.e., heard in the intercom
>only with microphone and radio squelch gates closed? Is
>the intercom battery powered or powered from the bus?
>
><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> From what I've determined the electrical architecture in
> this plane is such a kludge that there ARE no distinct busses. For
> example, in the circuit breaker panel, the ground sides of the CBs are
> wired together with 14AWG wire, CB to CB in series, rather than in
> parallel to a bus (which could have been as simple as a piece of
> copper). As you mention in the Connection, obviously not the way to do
> it. I'll show it to you in Watsonville.
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Okay, it sounds like your airplane may be a good candidate
for substantial rehabilitation. We can discuss this more
at the seminar.
>If battery powered, how about trying a new battery . . .some
>audio systems become squealers when the battery voltage drops
>and power source impedance goes up.
><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> Yesterday I flew a short hop battery-only (alternator
> switch off) and didn't hear any tone. As I recall voltage was about 13 V.
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Good. Let's turn the alternator back on and check for (1)
is noise present and (2) does it vary in pitch with
rpm. Do this check with (1) minimum loads . . . turn on
only those radios/audio system needed to have the potential
victims active and (2) maximum loads . . . turn everything
ON to get highest practical load on the alternator.
>We could use your airplane as a study topic at the Watsonville seminar.
>
><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
> I'll bring it if weather permits me to get into
> Watsonville VFR.
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Great.
>Bring all the drawings you have.
>
><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
>The only drawings I have are the ones I'm making through reverse
>engineering! But it's certainly educational.
I recall high school and college teachers telling me that the
best way to study in class was to make brief but good memory
jogging notes. At home in the evening, transcribe your notes
and ELABORATE on them based on what you have retained from the
class a few hours earlier. This will create a document that
will open LOTS of good memory doors when you re-read them to
review for the test.
Your effort to accurate document what's already installed
may yield good clues as to why things don't work well now
as well as lay the groundwork for upgrading the system
later. It's not a wasted effort.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> 10/08/03 |
| Subject: | Re: RE: AeroElectric-List Digest: 28 Mags - |
10/08/03
10/08/03
>
>
>Villi / Bob,
>
>Thanks for the info. Makes perfect sense as you describe, except... I was
>planning to use the dreaded key-operated mag / starter switch hence the
>thought about the relay. Perhaps its time to go for toggles instead.
>
>Cheers.
>
>Nev
Hmmmm . . . yup, them thar keyswitches do limit your options . . .
Bob . . .
________________________________________________________________________________
aeroelectric-list(at)matronics.com
| From: | richard(at)riley.net |
| Subject: | Re: magneto wiring |
> >Comments/Questions: Bob, bought your Connection book a few years back,
> >quick question: Starting an airplane with right mag energized can cause
> >kickback, so we start with just left on. What about inflight restart?
>
> The vast majority of airplanes (pushers being the
> most notable exceptions) will windmill the prop in
> flight. Restarting generally involves restoring fuel
> flow and power will resume.
Pushers windmill the prop nicely. In a canard pusher, the windmilling prop
reduces glide significantly (no more so than any other plane, but
canard-pushers is where my experience is.) Depending on what the prop
pitch is, since your minimum speed is limited by the canard stall speed,
you may not be able to get slow enough to stop the windmilling prop.
________________________________________________________________________________
| From: | Gary Liming <gary(at)liming.org> |
| Subject: | Re: Grounding fuel flow sender |
>
>I'm rebuilding the induction system on a Lyc IO-540. There's a Floscan
>transducer there already, from a previous engine instrument installation,
>but it looks like I'm going to have to re-position it.
>
>I know about keeping the fuel flow straight for as long as possible going
>in and out of the transducer, but at one point I was told that the
>transducer shouldn't be grounded - that it should be stepped off the engine
>on insulators, and that the fuel lines before and after the transducer
>should be rubber.
>
>This doesn't make a whole lot of sense to me, and I *really* don't want
>anything but stainless line for fuel on that side of the firewall. Does
>anyone know if this bit of advice is true, urban legend, or something
>inbetween?
The instructions I have for the Floscan transducer doesn't say anything
about not being grounded.
Hope that helps,
Gary Liming
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: magneto wiring |
>
>
>
> > >Comments/Questions: Bob, bought your Connection book a few years back,
> > >quick question: Starting an airplane with right mag energized can cause
> > >kickback, so we start with just left on. What about inflight restart?
> >
> > The vast majority of airplanes (pushers being the
> > most notable exceptions) will windmill the prop in
> > flight. Restarting generally involves restoring fuel
> > flow and power will resume.
>
>Pushers windmill the prop nicely. In a canard pusher, the windmilling prop
>reduces glide significantly (no more so than any other plane, but
>canard-pushers is where my experience is.) Depending on what the prop
>pitch is, since your minimum speed is limited by the canard stall speed,
>you may not be able to get slow enough to stop the windmilling prop.
Thanks for the data point on Richard. I don't recall now
where I was told that the pushers were more likely not
to windmill . . . I've been belabored of that information
for a number of years.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Grounding fuel flow sender |
>
> >
> >I'm rebuilding the induction system on a Lyc IO-540. There's a Floscan
> >transducer there already, from a previous engine instrument installation,
> >but it looks like I'm going to have to re-position it.
> >
> >I know about keeping the fuel flow straight for as long as possible going
> >in and out of the transducer, but at one point I was told that the
> >transducer shouldn't be grounded - that it should be stepped off the engine
> >on insulators, and that the fuel lines before and after the transducer
> >should be rubber.
> >
> >This doesn't make a whole lot of sense to me, and I *really* don't want
> >anything but stainless line for fuel on that side of the firewall. Does
> >anyone know if this bit of advice is true, urban legend, or something
> >inbetween?
One of the very best ways to get information about a product
is to contact the folks who build it. A short not to
mailto:support(at)flowscan.com may do wonders for your confidence
with the installation.
Bob . . .
________________________________________________________________________________
| From: | Mark Phillips <ripsteel(at)edge.net> |
| Subject: | Re: List of tools |
I heartily second Werner's suggestion- I just completed wiring my RV
using tools and materials almost exclusively from B&C, including the
alternator, contactors, wires etc. Once you have a firm understanding
of the invaluable information in the 'Connection and have your system
design firmed up, it's easy to place one order to B&C and you should be
able to get the whole package sent- (you DO have UPS, don't you?) ..just
order a LOT more wire and fastons than you estimate you'll need!! Bob
Nuckolls, the Aeroelectric list & B&C- does it get any better?
Best wishes- Mark Phillips, RV-6A Columbia, TN, USA
Werner Schneider wrote:
>
> Hello Mickey,
>
> you're going the fast lane =(;o), you will get all the electrical tools in
> Switzerland, just at a much
> higher price =(;o(( (www.distrelec.ch).
>
> You can have a look at http://www.bandcspecialty.com/parts.html I bought
> from them the crimp tools, a lot of wire, the toogle buttons, plugs, fastons
> and the OV protection module, bus bars etc.
>
> For more details contact me direct.
>
> Before you start electrical wise you should go and design your setup with a
> load analysis.
>
> Werner
>
> ----- Original Message -----
> From: "Mickey Coggins" <mick-matronics(at)rv8.ch>
> To:
> Subject: AeroElectric-List: List of tools
>
>
>
>>
>
>
>>Hi,
>>
>>I'm just starting my RV8, and due to my geographically
>>challenged location (mountains of Switzerland) I would
>>like to buy all the tools, testers, and meters that I
>>might for the electrical system of my RV8. I can get
>>almost nothing locally, except very simple household
>>wiring supplies.
>>
>>I have purchased the 'Connection, as Bob calls it, and
>>am in the process of reading it. I'll be visiting the
>>US next week, and I'd like to pick up as much of the
>>stuff as I possibly can during this visit. I'll be
>>back in the states for Thanksgiving as well, so it's
>>not critical that I get everything in this visit.
>>
>>Does anyone know of a list of tools, and possibly
>>suppliers, that I could use? I would much prefer to
>>err on the side of having a tool that I will never use
>>than to need something and to not have it, and have to
>>wait for it to be delivered.
>>
>>I guess if I don't hear any suggestions I'll just buy
>>everything I can find in all the aviation catalogues,
>>but that seems a bit wasteful.
>>
>>Thanks!
>>Mickey
>>
>>
>>--
>>Mickey Coggins
>>http://www.rv8.ch/
>>
>>
>>
>
>
>
>
>
>
>
>
________________________________________________________________________________
| From: | "Fergus Kyle" <VE3LVO(at)rac.ca> |
Just for info, the NA64 Yale with partial flap will stall and flick
starboard to inverted, AND 30deg nose down, in 1/30 second (timed it
myself). That's the interval of one video/cine shot. So it's "blue up, brown
down - brown up, blue down - dead" in one swell foop.
Admittedly, older aircraft require careful study, but it seems to me
that certified designs require a physical warning three knots above normal
stall (at least here anyway). It might be a good idea to see if yours does.
Cheers, Ferg
________________________________________________________________________________
| Subject: | Re: magneto wiring |
| From: | "Matt Prather" <mprather(at)spro.net> |
Just one more comment.... I believe the cp configuration is more
likely to not windmill, as compared to tractor configs. One isssue
is that the cp's often run very high pitch/low diameter props (56in dia
x 70in pitch is a common Varieze prop) in order to take advantage of the
relative aerodynamic cleanliness of the configuration. This means that
relatively high airspeeds are required for the prop to generate enough
lift to make the torque on the crank to maintain rotation. Most tractor
configured airplanes of similar horsepower don't use that much prop pitch.
The other issue is that if the prop does stop, lots of airspeed may be
required to get it going again (maybe as much as 115kts). This is peculiar
to cp's as well, because the prop is most likely to stop in a position
where it is hidden from the slipstream by the wings. 3 blade props on
cp's are much less likely to suffer from this because you can't more than
of the 3 blades behind the wing at the same time.
Richard is right, in that cp's do windmill, but maybe not as readily.
Sorry for the long OT.
Regards,
Matt Prather
VE N34RD
>
>
>>
>>
>>
>> > >Comments/Questions: Bob, bought your Connection book a few years
>> back, quick question: Starting an airplane with right mag energized
>> can cause kickback, so we start with just left on. What about
>> inflight restart?
>> >
>> > The vast majority of airplanes (pushers being the
>> > most notable exceptions) will windmill the prop in
>> > flight. Restarting generally involves restoring fuel
>> > flow and power will resume.
>>
>>Pushers windmill the prop nicely. In a canard pusher, the windmilling
>> prop reduces glide significantly (no more so than any other plane, but
>> canard-pushers is where my experience is.) Depending on what the prop
>> pitch is, since your minimum speed is limited by the canard stall
>> speed, you may not be able to get slow enough to stop the windmilling
>> prop.
>
> Thanks for the data point on Richard. I don't recall now
> where I was told that the pushers were more likely not
> to windmill . . . I've been belabored of that information
> for a number of years.
>
> Bob . . .
>
>
> http://www.matronics.com/trouble-report
________________________________________________________________________________
| From: | Richard May <ram45(at)comporium.net> |
| Subject: | Crowbar OV protection |
I've been looking at the wiring of the crowbar overvoltage module, but one
thing concerns me. What if the circuit breaker shorts out??? Then what?
Total meltdown.
I know of that happening once on a Lockheed L-1011, and they don't put
anything but the best in those birds. The weakness of the crowbar OV system
is it is totally reliant on a perfect circuit breaker. I guess the thing to
do is test it constantly.
________________________________________________________________________________
| From: | Rino <lacombr(at)nbnet.nb.ca> |
| Subject: | Re: Crowbar OV protection |
Richard May wrote:
>
>
> I've been looking at the wiring of the crowbar overvoltage module, but one
> thing concerns me. What if the circuit breaker shorts out??? Then what?
> Total meltdown.
> I know of that happening once on a Lockheed L-1011, and they don't put
> anything but the best in those birds. The weakness of the crowbar OV system
> is it is totally reliant on a perfect circuit breaker. I guess the thing to
> do is test it constantly.
A fuse does not short out.
Rino
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Crowbar OV protection |
>
>I've been looking at the wiring of the crowbar overvoltage module, but one
>thing concerns me. What if the circuit breaker shorts out??? Then what?
>Total meltdown.
>I know of that happening once on a Lockheed L-1011, and they don't put
>anything but the best in those birds. The weakness of the crowbar OV system
>is it is totally reliant on a perfect circuit breaker. I guess the thing to
>do is test it constantly.
Any ov protection system is totally reliant on solder joints that might
not have been made correctly, resistors that may open, diodes that
may short, transistors that may crack, etc. etc. . . .
I've heard the "shorted" or "failed to open" stories for circuit
breakers . . . even a few persist around RAC from back in the
Beech days. Funny thing, nobody claims to have seen it personally.
There were no official condition reports written or investigations
as to root cause. Do you know what kind of circuit breaker
was involved in the L1011 incident? There are perhaps a half
dozen or more technologies that could be involved. One that comes
to mind are "remote controlled" circuit breakers which are
really contactors driven by specialty sensing circuits for current
and a myriad of other parameters to decide when to open
or stay closed. The parts count on these critters is high and
the need for extra-ordinary care in qualification and
fabrication is equally high. Do you know if this particular
"dark-n-stormy-night" breaker was one of the simple, bi-metal
devices popular in our designs (which by the way, tend to fail open)
and not one of the "super breakers" that the air-transport
guys are fond of?
I've designed dozens of ov relay systems and have first-hand
experience with making them last under the most demanding
requirements levied by the OEMs. I've also documented the
way they add to the voltage drops in the field supply feeder
that increase probability of regulator instability.
OV relays have performed reasonably well for decades. If you
don't mind their shortcomings and find them more comforting,
then by all means. However, I can find no documented data
to suggest the crowbar system implemented with a popular,
relatively low cost breaker having a bi-metal sensor is more
likely to malfunction than the relay based ov protection
system.
You could add a fusible link to back up a breaker
if you're unconvinced as to its quality and failure modes . . .
or leave the breaker out completely and use a fuse. This
leaves you no options for dealing with nuisance trips but
then, this is just one of MANY forms of alternator failure
and you're going to be ready do deal with that comfortably
no mater what the cause . . . right?
Bob . . .
________________________________________________________________________________
| From: | "Rob W M Shipley" <rob(at)robsglass.com> |
| Subject: | Strobe head fix and silicone |
Subject: Re: AeroElectric-List: Strobe head fix
>Can silicone be used to re-seal the glass lens to the transformer/plastic
>base of the head ?
>If so, what grade is best ?
Bob's answer was
Electronic grade (does not smell of vinegar).
This is also known as "neutral cure" silicone and should be available for less
than five bucks a tube from any auto glass shop. This is a far safer product
to use around any metal construction as it is non acidic than the normal silicones
which contain acetic acid.
Clean the surfaces carefully with alcohol and allow to dry before applying. Depending
on how thickly you apply it it can take over twenty four hours to fully
cure so make sure the parts are held together at least overnight.
Good luck
Rob
Rob W M Shipley
RV9A N919RV (res) Fuselage
________________________________________________________________________________
| From: | "Jim Jewell" <jjewell(at)telus.net> |
| Subject: | Re: Grounding fuel flow sender |
AeroElectric-List message posted by: richard(at)riley.net
I'm rebuilding the induction system on a Lyc IO-540. There's a Floscan
transducer there already, from a previous engine instrument installation,
but it looks like I'm going to have to re-position it.
>I know about keeping the fuel flow straight for as long as possible going
>in and out of the transducer, but at one point I was told that the
>transducer shouldn't be grounded - that it should be stepped off the engine
>on insulators, and that the fuel lines before and after the transducer
>should be rubber.
>This doesn't make a whole lot of sense to me, and I *really* don't want
>anything but stainless line for fuel on that side of the firewall. Does
>anyone know if this bit of advice is true, urban legend, or something
>inbetween?
From the wording of the advice you where given I would say the intent was to
advise you isolate the Floscan unit from mechanical vibration as apposed to
electrical grounding.
The suggestion; "that it should be stepped off the engine on insulators"
would make sence if you intend to mount it 'on the engine'. the internals
of the unit do not take well to being unduly vibrated.
Mount the Floscan on the firewall and It should work just fine.
As far as your concern about grounding the unit electrically take Bob's
advice and call the product maker. I expect that they will happy to set
things straight for you.
Jim in Kelowna
________________________________________________________________________________
| From: | "Steve Richard" <steve(at)oasissolutions.com> |
Can the pin shown on the B&C web site (Part # S604P) be used for AMP CPC
connectors? Or are the pins shown on page 566 of the mouser catalog the
same as the B&C pins?
http://www.bandcspecialty.com/cgi-bin/ez-catalog/cat_display.cgi?24X358218
http://www.mouser.com/catalog/615/566.pdf
Part #'s
571-2050901
571-2058412
Thanks
Steve Richard
steve(at)oasissolutions.com
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>Can the pin shown on the B&C web site (Part # S604P) be used for AMP CPC
>connectors? Or are the pins shown on page 566 of the mouser catalog the
>same as the B&C pins?
>
>http://www.bandcspecialty.com/cgi-bin/ez-catalog/cat_display.cgi?24X358218
>
>http://www.mouser.com/catalog/615/566.pdf
Yes, the CPC series 2 connectors use the same pins as
the crimp D-Subs. The "20DM" (Dsub Military) pins in
the Mouser catalog are the same as what's offered
by B&C.
Bob . . .
________________________________________________________________________________
| From: | Richard May <ram45(at)comporium.net> |
| Subject: | Re: Crowbar OV protection |
A fuse, hmm, good idea. My plane has a 60 amp alternator, and had a 40 amp
breaker installed, due to, I suppose the previous owner not wanting to
change the breaker when he upgraded the alternator. But that 40 amp breaker
has never popped. So if I install a 60 amp fuse, the only way it would ever
melt would be from a problem that I wouldn't want it back from anyway. This
fuse, coupled with the crowbar OV module would represent a very sound and
safe electrical system.
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Crowbar OV protection |
>
>A fuse, hmm, good idea. My plane has a 60 amp alternator, and had a 40 amp
>breaker installed, due to, I suppose the previous owner not wanting to
>change the breaker when he upgraded the alternator. But that 40 amp breaker
>has never popped. So if I install a 60 amp fuse, the only way it would ever
>melt would be from a problem that I wouldn't want it back from anyway.
I'm not sure we're together here. The fuse I was referring to in
my earlier post would have replaced any kind of 5A FIELD breaker
that you might be worried about . . . never saw a fuse fail to
open when hard faulted. The fuse you're talking about is in the
alternator b-lead (output).
See Figure 17-2 and associated text on page 17-7 of the 'Connection.
The fact that you've never seen this breaker open says only
that you have yet to generate the perfectly normal condition
that will open it. If you choose to "fuse" this lead then consider
the discussion in these threads:
http://www.aeroelectric.com/articles/fusvsbkr.html
and in particular the second half where I was taken
to task for under-sizing a fast acting, JJN/JJS series
b-lead fuse that we no longer offer nor recommend.
http://www.aeroelectric.com/articles/fusvbkr2.html
The device of choice is the ANL60 or even an ANL35.
If you look at the fusing characteristics of these devices
at
http://www.aeroelectric.com/articles/anl/anl.pdf
you'll see that you're unlikely to nuisance trip
these devices on a 60A alternator on the coldest day.
Irrespective of the circuit protection you choose for
the b-lead, there is no bearing on the choice of
configuration or operation of the ov protection
system. The b-lead fuse protects the rest of
the system from a hard fault inside the alternator
while the ov protection system wards off effects
of a failed regulator.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: sizing wire and protection for pitot tube |
>
>Comments/Questions: Bob, looking thru your book trying to find a
>chart/guide for selecting wire guage needed based on length of run, amps
>required, and application.
>Is there such a chart? If not, how is the wire size for a 15' run for a
>heated pitot tube that draws 11 amps at 14 volts determined?
That's a BIG pitot heater . . .
It's covered in the book. First, wire has to be large enough
not to run too hot for the current. The wire table (Figure 8-3)
suggests 16AWG for loads up to 12.5A. Since 12A breakers are
hard to come by, consider 14AWG wire protected at 15A. Now,
with 11A load, the 2.5 milliohm/foot resistance of 14AWG
will drop 11/2.5 or 27.5 millivolts per foot. A 15' run
drops 413 millivolts . . . less than the 5% (700 millvolt)
benchmark for 14 volt systems.
Now, I presume we're talking about a metal airplane where
you plan to use local ground for the pitot tube. If composite
and the wire run round trip is TWICE the 15' figure cited,
then your total drop with 14AWG would be 826 millivolts.
Probably still okay . . . but it wouldn't hurt if you increased
to 12AWG . . . the breaker/fuse could then be up-sized to 20A
and still protect the wire. If your pitot tube really draws
11A continuous in operation, it will draw about twice that
for several seconds during warm-up. If you're using fuses,
the probability of nuisance tripping a 15A fuse is pretty
good . . . a 15A breaker is much slower and would probably
stay closed.
So, the REAL criteria for selecting wire and fuse size
may have more to do with the long and high value inrush
characteristic of pitot tubes. 12AWG/20A is probably
your best choice for either metal or plastic airplane.
Bob . . .
________________________________________________________________________________
| From: | Jim Bean <jim-bean(at)att.net> |
What does the list think about putting the ELT in the wingtip of a metal
AC. It's the only place "inside" where it can radiate. It would seem
that the ELT would see the same deceleration as if in the fuselage. Also
the wings often survive better that the fuselage, particularly if they
are pulled off. The only problem I see is that the wingtip would have to
be removed once a year to change the batteries.
I have never seen this done so suspect that there MUST be something
wrong with it. :)
Jim Bean
RV-8
________________________________________________________________________________
| Subject: | Firewall Feedthru |
| From: | Jim Daniels <jwdanie(at)comcast.net> |
http://terminaltown.com/Pages/BPT.html
Has anyone tried one of these to get the master output to the starter
relay? Or should I just run a 4 awg wire loop? I was thinking of the
above and brass strips instead of wire with crimp/solder terminals.
Thoughts?
Some pics of a mockup:
http://home.comcast.net/~jwdanie/temp.html
Jim Daniels
________________________________________________________________________________
| From: | "Larry Bowen" <Larry(at)BowenAero.com> |
Lots of screw in those wingtips.
So far, I like the placement of my Pointer ELT under the VS. Not flying
yet.....
-
Larry Bowen, RV-8 finish
Larry(at)BowenAero.com
http://BowenAero.com
> -----Original Message-----
> From: Jim Bean [mailto:jim-bean(at)att.net]
> Sent: Tuesday, October 14, 2003 10:05 PM
> To: rv-list(at)matronics.com
> Subject: AeroElectric-List: ELT in wingtip
>
>
>
> What does the list think about putting the ELT in the wingtip
> of a metal
> AC. It's the only place "inside" where it can radiate. It would seem
> that the ELT would see the same deceleration as if in the
> fuselage. Also
> the wings often survive better that the fuselage,
> particularly if they
> are pulled off. The only problem I see is that the wingtip
> would have to
> be removed once a year to change the batteries.
> I have never seen this done so suspect that there MUST be something
> wrong with it. :)
> Jim Bean
> RV-8
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: ELT in wingtip |
>
>What does the list think about putting the ELT in the wingtip of a metal
>AC. It's the only place "inside" where it can radiate. It would seem
>that the ELT would see the same deceleration as if in the fuselage. Also
>the wings often survive better that the fuselage, particularly if they
>are pulled off. The only problem I see is that the wingtip would have to
>be removed once a year to change the batteries.
>I have never seen this done so suspect that there MUST be something
>wrong with it. :)
>Jim Bean
>RV-8
It's a pretty good idea to put the ELT in a position least likely
to be wiped off or munched during the unplanned arrival with the
earth. The tail section just forward of the vertical fin is an
enclosed volume most likely to remain intact . . . the vertical
fin provides a modicum of protection for an ELT antenna in a
noseover.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Firewall Feedthru |
>
>http://terminaltown.com/Pages/BPT.html
>
>Has anyone tried one of these to get the master output to the starter
>relay? Or should I just run a 4 awg wire loop? I was thinking of the
>above and brass strips instead of wire with crimp/solder terminals.
>
>Thoughts?
>
>Some pics of a mockup:
>http://home.comcast.net/~jwdanie/temp.html
Copper strip is better. You can get flashing copper scraps
from some roofing and/or plumbing companies.
That feed through is a plastic insulator rated at
250F max . . . not especially resistant to fuel
fed fire.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Strobes and comm Ant |
>
>
>Friends, I'm building an AeroCanard and my Comm Ant are in the
>winglets. Problem is I have to run the strobe wiring out the same
>hole. Does anyone have an opinion on this? Will it work?
Probably . . . but you might hear the strobes in the comm
receiver even if you DO run the wires through separate holes.
The risk is low. Give it a try.
Bob . . .
________________________________________________________________________________
| From: | "Mark Banus" <mbanus(at)hotmail.com> |
| Subject: | Need for relays? |
Bob,
Just received plans for an engine install. It shows all switches with #22 wire
going to relays (22 Relays). My understanding is that certain heavy loads
(Pitot heat etc) need a relay as the switches can't handle the amps. But do I
need relays for 3-10 amp circuits? More relays are more components to fail.
I have looked at 125v 10 and 15 amp rocker switches from Digikey that look like
they can handle the current. Pro/cons? Thanks
________________________________________________________________________________
| Subject: | Track width on PCB |
Hi Bob and all,
Our aileron trim servo (RAC trim) will be commanded through a small dual
relay. I'm in the process of designining a suitable PCB for this relay,
diodes and wires.
The relay is rated at 10 amps, but the circuit will be fused at 1 to 3 amps.
Questions :
-What is the adequate width of the circuit board tracks for 3 amps ?
- And what width for, say, 10 amps ?
-Is there an accepted relationship between current and track width ?
Thank you
Regards
Gilles
________________________________________________________________________________
| From: | "David Swartzendruber" <dswartzendruber(at)earthlink.net> |
| Subject: | Track width on PCB |
My chart shows that to obtain a 10deg C rise in temperature using 2oz
copper the following track widths would be used:
10A .170in
5A .070in
3A .032in
Of course, if you've got the room, making them even wider doesn't hurt
anything.
Dave in Wichita
> -----Original Message-----
> From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-
> aeroelectric-list-server(at)matronics.com] On Behalf Of Gilles.Thesee
> Sent: Wednesday, October 15, 2003 9:06 AM
> To: aeroelectric-list(at)matronics.com
> Subject: AeroElectric-List: Track width on PCB
>
> <Gilles.Thesee@ac-grenoble.fr>
>
> Hi Bob and all,
>
> Our aileron trim servo (RAC trim) will be commanded through a small
dual
> relay. I'm in the process of designining a suitable PCB for this
relay,
> diodes and wires.
> The relay is rated at 10 amps, but the circuit will be fused at 1 to 3
> amps.
>
> Questions :
>
> -What is the adequate width of the circuit board tracks for 3 amps ?
> - And what width for, say, 10 amps ?
>
> -Is there an accepted relationship between current and track width ?
>
> Thank you
> Regards
>
> Gilles
>
>
>
==
>
==
http://www.matronics.com/trouble-report
>
==
http://www.matronics.com/FAQ/AeroElectric-List.htm
>
==
>
>
________________________________________________________________________________
| From: | "Trampas" <tstern(at)nc.rr.com> |
| Subject: | Track width on PCB |
Try this link
http://www.geocities.com/CapeCanaveral/Lab/9643/TraceWidth.htm
Trampas
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of
Gilles.Thesee
Subject: AeroElectric-List: Track width on PCB
<Gilles.Thesee@ac-grenoble.fr>
Hi Bob and all,
Our aileron trim servo (RAC trim) will be commanded through a small dual
relay. I'm in the process of designining a suitable PCB for this relay,
diodes and wires.
The relay is rated at 10 amps, but the circuit will be fused at 1 to 3 amps.
Questions :
-What is the adequate width of the circuit board tracks for 3 amps ?
- And what width for, say, 10 amps ?
-Is there an accepted relationship between current and track width ?
Thank you
Regards
Gilles
________________________________________________________________________________
| From: | richard(at)riley.net |
| Subject: | Re: Strobe head fix and silicone |
Is "neutral cure" silicone as strong, weather resistant and temperature
restistant, etc, as the acetic acid stuff?
>
>Subject: Re: AeroElectric-List: Strobe head fix
>
> >Can silicone be used to re-seal the glass lens to the transformer/plastic
> >base of the head ?
> >If so, what grade is best ?
>Bob's answer was
> Electronic grade (does not smell of vinegar).
>
>This is also known as "neutral cure" silicone and should be available for
>less than five bucks a tube from any auto glass shop. This is a far safer
>product to use around any metal construction as it is non acidic than the
>normal silicones which contain acetic acid.
>Clean the surfaces carefully with alcohol and allow to dry before
>applying. Depending on how thickly you apply it it can take over twenty
>four hours to fully cure so make sure the parts are held together at least
>overnight.
>Good luck
>Rob
>Rob W M Shipley
>RV9A N919RV (res) Fuselage
>
>
________________________________________________________________________________
| From: | "David E. Nelson" <david.nelson(at)pobox.com> |
| Subject: | Re: Track width on PCB |
Hi Gilles,
I did a google seach (pcb track width current amps) and found a PCB track width
calculator:
http://www.geocities.com/CapeCanaveral/Lab/9643/TraceWidth.htm
Regards,
/\/elson
On Wed, 15 Oct 2003, Gilles.Thesee wrote:
>
> Hi Bob and all,
>
> Our aileron trim servo (RAC trim) will be commanded through a small dual
> relay. I'm in the process of designining a suitable PCB for this relay,
> diodes and wires.
> The relay is rated at 10 amps, but the circuit will be fused at 1 to 3 amps.
>
> Questions :
>
> -What is the adequate width of the circuit board tracks for 3 amps ?
> - And what width for, say, 10 amps ?
>
> -Is there an accepted relationship between current and track width ?
>
> Thank you
> Regards
>
> Gilles
>
>
>
>
>
>
>
--
~~ ** ~~ If you didn't learn anything when you broke it the 1st ~~ ** ~~
time, then break it again.
________________________________________________________________________________
| From: | Richard May <ram45(at)comporium.net> |
| Subject: | Re: Crowbar OV protection |
You know, I think something may be amiss also. When I did the test to check
the crowbar OV feature of my LR3A voltage regulator, by using the jumper
wire procedure, it tripped my alternator breaker, not the field breaker.
That's why I was concerned about the crowbar's method of tripping the
alternator breaker. I figured it must be a heck of a jolt to the whole
electrical system to send a short that would exceed the capacity of my 40
amp breaker through the wires. Once I got the LR3 installed, cranked up the
engine, it showed a positive charge, and everything seemed normal. The amp
gauge showed a strong charge, and the volt meter went up to 14. But
yesterday, when I turned on the master, (engine off) I noticed that
regardless how many electrical items I turned on, the amp gauge would never
move into the negative range. And I was turning on landing lights, ect..
and the amp needle never budged. I'm not sure if my amp gauge is broken,
and only reading in the positive range, or the wiring is wrong.
R.May
________________________________________________________________________________
| From: | Mcculleyja(at)aol.com |
| Subject: | Terra TX 760 D VHF Transceiver |
My Terra 760 D comm unit was installed in a new panel several years ago while
building the aircraft that recently made first flight. At time of
installation, it performed well during checks with airborne friends while I still
had it
in the garage completing other tasks. However, during the first several
flights it would not transmit beyond about a mile, but the reception was
outstanding. Subsequently, after borrowing an identical unit for flight comparisons
and after having mine in and out of the tray a few times, mine is now reasonably
good out to at least 35 miles, but still slightly weaker than the borrowed
unit. Is it possible that the removal/replacement process several times
polished the coax connector pins to reduce some mild corrosion or otherwise reduce
impedance through the connector? If so, was the receiver not also affected
simply because slight impedance increase in the antenna/coax system just doesn't
affect reception proportionally as much as transmission? OR do I still
probably have an internal deficiency in my unit? Any comments, guidance----anyone?
Thanks.
Jim McCulley
mcculleyja(at)aol.com
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Need for relays? |
>
>Bob,
> Just received plans for an engine install. It shows all switches with
> #22 wire going to relays (22 Relays). My understanding is that certain
> heavy loads (Pitot heat etc) need a relay as the switches can't handle
> the amps. But do I need relays for 3-10 amp circuits? More relays are
> more components to fail. I have looked at 125v 10 and 15 amp rocker
> switches from Digikey that look like they can handle the current.
> Pro/cons? Thanks\
Your switches will probably be just fine directly
switching the loads. See
http://www.aeroelectric.com/articles/swtchrat.pdf
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: question on Z1 |
>Below is the result of your inquiry. It was submitted by
>Don Burton (dburton(at)nlxcorp.com) on Wednesday, October 15, 2003 at 07:20:23
>
>Wednesday, October 15, 2003
>
>Don Burton
>
>,
>Email: dburton(at)nlxcorp.com
>Comments/Questions: Bob,
>I had a question on the Z1 drawing and the auto bus shedding.
First, I'll suggest that you download the updates to your book
which you can find at http://www.aeroelectric.com/articles.html
> I can't figure out how this can work when there is a 4awg wire from the
> battery contactor to the main bus. It seems that even if the alternator
> fails, as long as the battery contactor is closed, the main bus will be
> powered.
Yup, when you go to battery-only operations, you turn
the master switch OFF and e-bus alternate feed switch ON so
ONLY the endurance bus gets powered . . . .
>It seems that the essential bus feed switch should be normally open?
Yes . . . except during battery-only operations.
>I may have misunderstood the alt/bat switch. Shouldn't this be a 3
>position switch to turn the alternator on/off with the bat contactor
>closed (i.e. Battery & Alternator Off /Battery On & Alternator Off
>/Battery On & Alternator On).
The earlier diagrams like Z-1 simply bring the battery and
alternator ON and OFF together. If you have a crowbar ov
protection system with pullable breaker, you have a handy
means for battery-only ops of main bus by pulling breaker
either on the ground or in flight.
Later versions like Z-11 suggest another option of using
a progressive transfer 2-10 switch to offer a mid, battery
only position. Either system works fine and the 2-3 switch
shown in figure Z-1 is less expensive.
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Need for relays? P.S. |
>
>Bob,
> Just received plans for an engine install.
> It shows all switches with #22 wire going to relays
> (22 Relays).
Just out of curiosity, how many things in your airplane
need to have panel mounted switches for control? . . .
and who's installation drawings suggest using relays
to control everything? I am suspicious . . . if the
supplier of your engine and its recommended installation
instructions doesn't know enough about system architecture
to AVOID unnecessary complexity, I'd be skeptical of
their overall system knowledge.
Not raising any red flags . . . but it would be interesting to
understand more about the system you're working with.
Bob . . .
________________________________________________________________________________
| From: | DWENSING(at)aol.com |
| Subject: | Re: Strobe head fix and silicone |
In a message dated 10/15/03 11:04:50 AM Eastern Daylight Time,
richard(at)riley.net writes:
> Is "neutral cure" silicone as strong, weather resistant and temperature
> resistant, etc., as the acetic acid stuff?
>
There are various neutral cure silicone sealants. Some are flowable- some are
not. Some are formulated for electronic application while others are
formulated for construction application such as adhering to concrete. And there
are
others. Suggest you follow Bob's lead and stick with the electronic grade. For
the most part the weather resistance and temperature stability of the neutral
cure are about the same as the acetic acid cured stuff. And unless you are
using it as a structural adhesive the adhesion, tear strength and elongation
should be adequate for application.
Dale Ensing
________________________________________________________________________________
| From: | "Ernest Kells" <ernest.kells(at)sympatico.ca> |
| Subject: | Re: Heated Pitot Wiring |
Bob: I have a Vans RV-9A metal plane. I have installed a Warren Gretz
heated pitot tube (AN5812-12 12V).
Based upon your post 18 months ago I have started installing the wire - -
14awg wire (16 foot run) and a 15Amp fuse. I researched your post of Feb 1
2002 where you suggest 14awg and a 20amp fuse. On Oct 14, 2003 you say
12awg and 20 amp fuse. I don't know if I should rip out the fuselage wire
to use 12 awg wire. I am Canadian and plan to do winter flying, so nuisance
trips are not acceptable. Also, I would like to be able to consider heat
seats, if necessary.
Can you help me with this paradox? Thanks
Ernest Kells - RV-9A O235-N2C, Wood Prop
90 plus % Complete - Wiring
________________________________________________________________________________
| From: | "Werner Schneider" <wernerschneider(at)compuserve.com> |
| Subject: | Re: Heated Pitot Wiring |
Hello Ernest,
I have exactly the same pitot in my Glastar, I did check current, it shows
12 A on switch on and stabilize on 6.8 A thereafter, this was measured
battery only operation on ground, I've used AWG 14 and a 15A fuse I guess
about 16-20ft of lenght. I did not use it very often so far (9.75h on the
tacho), but the 3-4 times I tested it I had no blown fuses.
Hope it helpes
Werner
----- Original Message -----
From: "Ernest Kells" <ernest.kells(at)sympatico.ca>
Subject: Re: AeroElectric-List: Heated Pitot Wiring
>
> Bob: I have a Vans RV-9A metal plane. I have installed a Warren Gretz
> heated pitot tube (AN5812-12 12V).
>
> Based upon your post 18 months ago I have started installing the wire - -
> 14awg wire (16 foot run) and a 15Amp fuse. I researched your post of Feb
1
> 2002 where you suggest 14awg and a 20amp fuse. On Oct 14, 2003 you say
> 12awg and 20 amp fuse. I don't know if I should rip out the fuselage
wire
> to use 12 awg wire. I am Canadian and plan to do winter flying, so
nuisance
> trips are not acceptable. Also, I would like to be able to consider heat
> seats, if necessary.
>
> Can you help me with this paradox? Thanks
>
> Ernest Kells - RV-9A O235-N2C, Wood Prop
> 90 plus % Complete - Wiring
>
>
________________________________________________________________________________
| From: | "Gary Casey" <glcasey(at)adelphia.net> |
| Subject: | Pitot tube thermostat |
Has anyone implemented a thermostatically-controlled pitot tube heating
system? On the Lancair I'm building I tested the pitot tube heater and it
seems to be way more powerful than it needs to be, or at least what I would
expect. I'm afraid that if it is left on while on the ground it might
actually overheat the plastic in the wing. But then if a simple
thermostatic switch were connected in series there are failure modes that
might not be detectable. Just wondered if anyone has gone through this
before.
Gary Casey
Lancair ES
________________________________________________________________________________
| From: | "Neville Kilford" <nkilford(at)etravel.org> |
| Subject: | Re: Pitot tube thermostat |
How about a simple air pressure switch in series with a "Pitot heater"
warning light? You would only receive the warning light if you have the
pitot heater on whilst on the ground.
Nev
----- Original Message -----
From: "Gary Casey" <glcasey(at)adelphia.net>
Subject: AeroElectric-List: Pitot tube thermostat
>
> Has anyone implemented a thermostatically-controlled pitot tube heating
> system? On the Lancair I'm building I tested the pitot tube heater and it
> seems to be way more powerful than it needs to be, or at least what I would
> expect. I'm afraid that if it is left on while on the ground it might
> actually overheat the plastic in the wing. But then if a simple
> thermostatic switch were connected in series there are failure modes that
> might not be detectable. Just wondered if anyone has gone through this
> before.
>
> Gary Casey
> Lancair ES
>
>
________________________________________________________________________________
| Subject: | Re: Pitot tube thermostat |
| From: | caspainhower(at)aep.com |
10/16/2003 10:22:34 AM
Another option would be to use a bi-metalic temperature switch (mounted in
the wing) to turn on the heater. If you use an indicating light to show
when the heater is on and an override for the switch (a dash mounted switch
by-passing the temp switch, the indicating light would wire into this
switch). That way failures will be detectable and the pitot heater can
still be manually controlled.
Craig S.
601 XL
How about a simple air pressure switch in series with a "Pitot heater"
warning light? You would only receive the warning light if you have the
pitot heater on whilst on the ground.
Nev
>
> Has anyone implemented a thermostatically-controlled pitot tube heating
> system? On the Lancair I'm building I tested the pitot tube heater and
it
> seems to be way more powerful than it needs to be, or at least what I
would
> expect. I'm afraid that if it is left on while on the ground it might
> actually overheat the plastic in the wing. But then if a simple
> thermostatic switch were connected in series there are failure modes that
> might not be detectable. Just wondered if anyone has gone through this
> before.
>
> Gary Casey
> Lancair ES
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________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Strobe head fix and silicone |
>
>Is "neutral cure" silicone as strong, weather resistant and temperature
>restistant, etc, as the acetic acid stuff?
That's a good question.
Here's a quick look at a non-acid version
http://www.americansealantsinc.com/asi335.htm
with more detailed specs here
http://www.americansealantsinc.com/tecasi335.htm
and one that stinks . . .
http://www.americansealantsinc.com/asi502.htm
http://www.americansealantsinc.com/tecasi502.htm
. . . of course, there are hundreds of comparable
products by various manufacturers but at first
blush, the two products cited above are in the same
ballpark for performance.
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: question on Z1 |
nlxcorp.com>
>Thanks Bob for such and immediate response!
>
>I'm still using the some of the old diagrams because those are the ones I
>have marked up when I thought I would be doing the electrical system (5
>years ago). I think I have all the updates, but not much has changed for
>my aircraft.
Understand . . .
>I'm glad I was correct on all counts (don't want my parents to think I
>wasted my time in engineering school). Regarding the auto bus shedding...
>it seems then the only reason to have the diode array is put power to the
>essential bus when the master switch is on. In a failed alternator
>scenario, the pilot must then be careful not to switch off the master
>switch before he switches on the alternate essential bus feed (the order
>you put in your response), or you will kill the essential bus momentarily.
yes . . . which is usually of no consequence . . .
>Unless there is some other reason for the diode array? I think 2
>switches, one for the main bus and one for the essential bus is best for
>me because, I don't think I want to have to remember the order. As a
>matter of fact... if I ran the fuel pump / primer valve to the battery
>bus, the essential bus turns into an avionics master switch!
The diode prevents inadvertent positioning of the switches
such that the endurance bus BACKFEEDS to the main bus . . .
potentially blowing the e-bus alternate feed fuse. I DO NOT
recommend replacing this with a switch. Also, resist the urge
to replace the alternate feed switch and with a two-position
switch for NORMAL/ALTERNATE power of the e-bus . . . this
offers a single point of failure for both power paths to
the e-bus.
See chapter 17 of the updates.
I will invite you to join us on the AeroElectric List
to continue this and similar discussions. It's useful to
share the information with as many folks as possible.
A further benefit can be realized with membership on
the list. There are lots of technically capable folks
on the list who can offer suggestions too. You can
join at . . .
http://www.matronics.com/subscribe/
Bob . . .
|---------------------------------------------------|
| A lie can travel half way around the world while |
| the truth is till putting on its shoes . . . |
| -Mark Twain- |
|---------------------------------------------------|
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>Comments/Questions: Bob, re your bond studs - BS-1. You specify E6000
>adhesive. I've used epoxy/flox per plans on my Velocity where aluminum has
>to be bonded to fibreglass. Of course I'll test, but do you see a problem
>with using epoxy/flox instead of E6000?
I'm not a subject matter expert on bonding. The only thing
I can attest to is my own testing with E-6000. No doubt,
there are many options. Ran across an interesting new
adhesive with some pretty amazing characteristics. It's
called Gorilla Glue . . . See:
http://www.gorillaglue.com/theglue/
I've got a bottle and will be doing some hands-on
testing for bonding the BS-1 and other tasks.
This stuff is water activated but waterproof
after setup. Doesn't stink. Doesn't melt plastic.
etc. etc.
>I'm not sure how many I'll need, does 50 seem a reasonable number to
>secure brake lines, oil lines (it's a canard with oil cooler in the nose)
>and various electrical bundles. I'd rather have 10 too many than 1 too few
>so any suggestions appreciated.
I had one guy order 100 of them! I hope he's ordering
for himself and another builder too . . . I can't imagine
needing 100 for the run-of-the-mill SE OBAM airplane project.
If you have some left over, just advertise them on the
List. I'll run out one day and there are NO known sources
for more. Who knows, after I run out, you might be able
to auction them off for a lot more than I get for them
now (basic studies in laws of supply and demand).
>Took your seminar in Watsonville last year it was excellent. I also lurk
>on the Aeroelectric list and continue to learn a lot..
Thank you for the kind words. Pass the word in your
neighborhood, there's another Watsonville program
coming up in a few weeks.
Holler if we can help.
Bob . . .
________________________________________________________________________________
| From: | Dwight Frye <dwight(at)openweave.org> |
| Subject: | ProCrimper II Dies / Question |
I picked up a spiffy AMP ProCrimper II and it came with the default
dies for the FASTON style of terminals. I want to also get dies to
crimp both BNC connectors, as well as Dsub style pins. I am wanting to
double check with the wizards here about which dies to get to be sure
I don't end up with the wrong thing for the job. In particular I want
to make sure I get the right dies to use with pins and connectors I
can purchase from B&C (my electrical component supplier of choice).
In looking at the flyer that comes with the unit (a copy of which can be
found at the URL http://www.openweave.org/RV7/misc/ProCrimperII.pdf) it
seems to me that for BNC connectors clearly the only choice is part
number 82074. For the Dsub pins I am less sure. There are two dies that
look likely ... 82068 and 82181. However, only the first of the two have
explicit references to Dsub pins ... so I'm guessing that the right die
to get here would be 82068. Am I on the right track?
It is also my thought that the bulk of my connections will be Dsub, BNC,
or FASTON crimps. Is there anything critical I'm missing here?
I believe this is my first posting to the Aeroelectric list, but I am
absolutely certain it will NOT be my last. :) Thanks for all the good
advice and assistance you folks provide!
-- Dwight
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: Pitot tube thermostat |
> Has anyone implemented a thermostatically-controlled pitot tube heating
> system? On the Lancair I'm building I tested the pitot tube heater and it
> seems to be way more powerful than it needs to be,
Gary et al:
I designed it and tested it in my refrigerator. This winter it will go out
into the snow. If you're interested let me know.
Check: www.periheliondesign.com/pitotc46.pdf C46 pitot tube for reference
and
www.periheliondesign.com/thermopitot.pdf I will revise the internal parts
but it should work the same.
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: | frequent flyer <jdhcv(at)yahoo.com> |
I think I already know the answer but if I'm going to
run wires for my position lights and my landing lights
out to the wing tips in my Glasair do I need two
seperate ground wires or or can I just run one wire
that will handle the curent for both lights?
Thanks,
Jack
__________________________________
________________________________________________________________________________
| From: | Joa Harrison <flyasuperseven(at)yahoo.com> |
| Subject: | thermistors for low fuel warning |
I have the need for two thermistors for low fuel warning. The first is for my
homebuilt and needs to be 14 vdc, very affordable, and fairly robust. The second
is for a 28vdc certified design (to replace a float switch) and must be made
for certified aircraft (or the military). I need info on the first one for
my hobby (well, thats what my wife calls it, I prefer to call it my secondary
vocation) and the second one is for my day job (and what I call my hobby!)
What would you all suggest?
Thanks!
Joa
---------------------------------
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Ground Wires |
>
>I think I already know the answer but if I'm going to
>run wires for my position lights and my landing lights
>out to the wing tips in my Glasair do I need two
>seperate ground wires or or can I just run one wire
>that will handle the curent for both lights?
>
>Thanks,
If you have a metal structure, why not ground each item
locally to structure? In any case, I try to avoid having
multiple systems share components . . . single failure
takes out both systems. But if it doesn't matter to you,
then what you propose will certainly function.
Bob . . .
________________________________________________________________________________
| From: | "Rob W M Shipley" <rob(at)robsglass.com> |
| Subject: | Neutral cure silicone |
It performs just as well as it's acetic acid curing counterpart. When you ask
if it is "as strong" as the other form do remember that none of the silicones
should be viewed as a structural adhesives. If you need a waterproof adhesive/sealer
which has significant strength you need to be considering urethane adhesives.
These are used to install auto windshields and in this application must
retain the windshield in the event of an airbag deploying. This can place
an almost instantaneous load of up to half a ton of outward pressure. I know
of one builder who used this type of adhesive to attach hi canopy to the frame
of a slider and I am actually considering the same method for my 9 tipper.
Fly safe
Rob
From: richard(at)riley.net
Subject: Re: AeroElectric-List: Strobe head fix and silicone
Is "neutral cure" silicone as strong, weather resistant and temperature
restistant, etc, as the acetic acid stuff?
>
>Subject: Re: AeroElectric-List: Strobe head fix
>
> >Can silicone be used to re-seal the glass lens to the transformer/plastic
> >base of the head ?
> >If so, what grade is best ?
>Bob's answer was
> Electronic grade (does not smell of vinegar).
>
>This is also known as "neutral cure" silicone and should be available for
>less than five bucks a tube from any auto glass shop. This is a far safer
>product to use around any metal construction as it is non acidic than the
>normal silicones which contain acetic acid.
>Clean the surfaces carefully with alcohol and allow to dry before
>applying. Depending on how thickly you apply it it can take over twenty
>four hours to fully cure so make sure the parts are held together at least
>overnight.
>Good luck
>Rob
>Rob W M Shipley
>RV9A N919RV (res) Fuselage
>
>
________________________________________________________________________________
| From: | Charlie Kuss <chaskuss(at)bellsouth.net> |
| Subject: | Transponder Main bus or Essential Bus |
Listers,
Which bus would you wire the Transponder to, and why?
Charlie Kuss
________________________________________________________________________________
| From: | "Bruce Gray" <Bruce(at)glasair.org> |
| Subject: | Transponder Main bus or Essential Bus |
Essential bus - The transponder has an off switch so why sweat it.
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
Charlie Kuss
Subject: AeroElectric-List: Transponder Main bus or Essential Bus
Listers,
Which bus would you wire the Transponder to, and why?
Charlie Kuss
==
==
==
==
________________________________________________________________________________
| From: | "Ernest Kells" <ernest.kells(at)sympatico.ca> |
| Subject: | Re: Transponder Main bus or Essential Bus |
I agree on the essential bus. But you could just leave it on - it will
consume very little power. It will be ready to use, especially in an
emergency. It only consumes non-trivial power when you need to transmit for
a few seconds.
Ernest Kells - RV-9A O235-N2C, Wood Prop
90 plus % Complete - seat kit arrived today
> Essential bus - The transponder has an off switch so why sweat it.
Bruce
> www.glasair.org
>
> Which bus would you wire the Transponder to, and why?
> Charlie Kuss
________________________________________________________________________________
| From: | "Rick Caldwell" <rickca(at)trib.com> |
| Subject: | Re: thermistors for low fuel warning |
Joa;
I am interested in how you are going to design your low level waring
system? Are you looking for a temperature change? Or is their another use
for thermistors? If I can help out let me know.
Rick Caldwell
----- Original Message -----
From: "Joa Harrison" <flyasuperseven(at)yahoo.com>
Subject: AeroElectric-List: thermistors for low fuel warning
>
>
> I have the need for two thermistors for low fuel warning. The first is
for my homebuilt and needs to be 14 vdc, very affordable, and fairly robust.
The second is for a 28vdc certified design (to replace a float switch) and
must be made for certified aircraft (or the military). I need info on the
first one for my hobby (well, thats what my wife calls it, I prefer to call
it my secondary vocation) and the second one is for my day job (and what I
call my hobby!)
>
>
> What would you all suggest?
>
>
> Thanks!
>
>
> Joa
>
>
> ---------------------------------
>
>
________________________________________________________________________________
| From: | "Trampas" <tstern(at)nc.rr.com> |
| Subject: | thermistors for low fuel warning |
I found this on the web:
Toyota thermistor low fuel circuit description:
On a Toyota, they put a thermistor in the gas tank. It's not a potentiometer
type sending unit. The thermistor has current and voltage supplied to it and
a light bulb is in series with it continuously. This continuously heats up
the thermistor and at low fuel levels, the resistance drops causing the
indicator light to turn ON as the current goes up.
When the thermistor is immersed in fuel, the fuel keeps the thermistor
cooled off, the resistance remains high and the indicator light bulb does
not light up. Since the indicator always has current flowing through it and
the thermistor, it only lights up when the fuel level gets low and uncovers
the thermistor. This thermistor line is yellow with a black stripe on my
late 90s
Here are some other links
www.hdk.co.jp/pdf/eng/e023101.pdf
www.scully.com/cgi-bin/pdf/60635_desc.pdf
Everything mustang has the sensors for $32
www.everythingmustang.com/Merchant2/
merchant.mv?Screen=CTGY&Store_Code=EM&Category_Code=THERME
Trampas
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Rick
Caldwell
Subject: Re: AeroElectric-List: thermistors for low fuel warning
Joa;
I am interested in how you are going to design your low level waring
system? Are you looking for a temperature change? Or is their another use
for thermistors? If I can help out let me know.
Rick Caldwell
----- Original Message -----
From: "Joa Harrison" <flyasuperseven(at)yahoo.com>
Subject: AeroElectric-List: thermistors for low fuel warning
>
>
> I have the need for two thermistors for low fuel warning. The first is
for my homebuilt and needs to be 14 vdc, very affordable, and fairly robust.
The second is for a 28vdc certified design (to replace a float switch) and
must be made for certified aircraft (or the military). I need info on the
first one for my hobby (well, thats what my wife calls it, I prefer to call
it my secondary vocation) and the second one is for my day job (and what I
call my hobby!)
>
>
> What would you all suggest?
>
>
> Thanks!
>
>
> Joa
>
>
> ---------------------------------
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Strobe wire? |
>
>Comments/Questions: Hi Bob....I have a wing off the plane right now, and
>before I re-mount it, I want to run the strobe wires through it from tip
>to root. I haven't yet bought the strobes (resistance to Whelan's
>ridiculous pricing I expect) but I intend to use Whelan heads probably
>with a Nova power supply.
>
>Can you advise the wire spec that I should run?
There are dozens of suitable wires. Problem is that most
suppliers no longer offer cut lengths to order. You have to
order a whole spool (usually 100' minimum). The wire you're
looking for is 18 or 16 AWG triple with overall shield. You
might check with local installers of audio and industrial
control systems. They may have open spools of something
suitable and would be willing to sell you the 40 feet or
so that you need.
Consider this instead. If you buy a Whelan kit, it will come
with the wire. How about running a conduit of Nyloflo or
similar tubing from root to tip now. When you get your kit
later, it will be easy to run the wires in.
I will invite you to join us on the AeroElectric List
to continue this and similar discussions. It's useful to
share the information with as many folks as possible.
A further benefit can be realized with membership on
the list. There are lots of technically capable folks
on the list who can offer suggestions too. You can
join at . . .
http://www.matronics.com/subscribe/
Thanks!
Bob . . .
|---------------------------------------------------|
| A lie can travel half way around the world while |
| the truth is till putting on its shoes . . . |
| -Mark Twain- |
|---------------------------------------------------|
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Transponder Main bus or Essential Bus |
See chapter 17 of the 'Connection or if you don't have the
book, download
http://www.aeroelectric.com/articles/Rev9/ch17-9.pdf
>I agree on the essential bus. But you could just leave it on - it will
>consume very little power. It will be ready to use, especially in an
>emergency.
Repeat after me, "We don't have "EMERGENCIES" in our airplanes,
only certified ships are designed and regulated to precipitate
EMERGENCIES".
> It only consumes non-trivial power when you need to transmit for
>a few seconds.
>Ernest Kells - RV-9A O235-N2C, Wood Prop
> 90 plus % Complete - seat kit arrived today
>
> > Essential bus - The transponder has an off switch so why sweat it.
>Bruce
> > www.glasair.org
> >
> > Which bus would you wire the Transponder to, and why?
> > Charlie Kuss
>
>
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| From: | "Werner Schneider" <wernerschneider(at)compuserve.com> |
| Subject: | Re: thermistors for low fuel warning |
Interesting approach, would wonder what happens if you have a fuel injected
engine with a return line (of "hot" fuel) back into the tanks.
I'm using a optical device in my Glastar, works great and as it is LED it
needs nearly no power!!
http://www.ppavionics.com/LFL.htm
Werner
----- Original Message -----
> When the thermistor is immersed in fuel, the fuel keeps the thermistor
> cooled off, the resistance remains high and the indicator light bulb does
> not light up.
________________________________________________________________________________
| From: | "Bill Hibbing" <n744bh(at)bellsouth.net> |
| Subject: | Re: Strobe wire? |
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: AeroElectric-List: Re: Strobe wire?
>
>
> >
> >Comments/Questions: Hi Bob....I have a wing off the plane right now, and
> >before I re-mount it, I want to run the strobe wires through it from tip
> >to root. I haven't yet bought the strobes (resistance to Whelan's
> >ridiculous pricing I expect) but I intend to use Whelan heads probably
> >with a Nova power supply.
> >
> >Can you advise the wire spec that I should run?
>
> There are dozens of suitable wires. Problem is that most
> suppliers no longer offer cut lengths to order. You have to
> order a whole spool (usually 100' minimum). The wire you're
> looking for is 18 or 16 AWG triple with overall shield. You
> might check with local installers of audio and industrial
> control systems. They may have open spools of something
> suitable and would be willing to sell you the 40 feet or
> so that you need.
>
Check www.strobesnmore.com . He can sell you the Nova power supply and
cable by the foot. If you're using only 2 strobe heads the XPak 604 will do
the job for you. I know a lot of folks are using the 904 but with only 2
heads that power supply (904) reduces the power output. This is not the
case with the 604. If you're using more than 2 flash tubes it's a mute
point. Just thought I'd pass it along.
Bill
Glasair SIIS-FT
________________________________________________________________________________
| From: | "Trampas" <tstern(at)nc.rr.com> |
| Subject: | thermistors for low fuel warning |
The approach works fine with fuel injected engines as proven by Toyota and
other automotive manufactures.
Basically it is a thermal dissipation problem. That is the fuel can
dissipate the heat from the slight current flow much easier than the air,
the fuel would have to be really hot to turn the light on, in which case you
will have a lot more problems, like no liquid fuel...
Trampas
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Werner
Schneider
Subject: Re: AeroElectric-List: thermistors for low fuel warning
Interesting approach, would wonder what happens if you have a fuel injected
engine with a return line (of "hot" fuel) back into the tanks.
I'm using a optical device in my Glastar, works great and as it is LED it
needs nearly no power!!
http://www.ppavionics.com/LFL.htm
Werner
----- Original Message -----
> When the thermistor is immersed in fuel, the fuel keeps the thermistor
> cooled off, the resistance remains high and the indicator light bulb does
> not light up.
________________________________________________________________________________
| From: | "John Slade" <sladerj(at)bellsouth.net> |
| Subject: | thermistors for low fuel warning |
> I'm using a optical device in my Glastar, works great and as it is LED it
> needs nearly no power!!
>
> http://www.ppavionics.com/LFL.htm
$405 per tank ??? there has to be a less expensive way. I'd be interested in
learning more about that thermistor arrangement.
John Slade
________________________________________________________________________________
| Subject: | Re: Transponder Main bus or Essential Bus |
:-)
Also, I liked your change of name from "Essential" bus to "Endurance"
bus... if something is truly essential to continued flight, it should go
on the battery bus...
-John
Robert L. Nuckolls, III wrote:
>
> See chapter 17 of the 'Connection or if you don't have the
> book, download
>
> http://www.aeroelectric.com/articles/Rev9/ch17-9.pdf
>
>
>
>
>>I agree on the essential bus. But you could just leave it on - it will
>>consume very little power. It will be ready to use, especially in an
>>emergency.
>>
>>
>
> Repeat after me, "We don't have "EMERGENCIES" in our airplanes,
> only certified ships are designed and regulated to precipitate
> EMERGENCIES".
>
>
>
>
>> It only consumes non-trivial power when you need to transmit for
>>a few seconds.
>>Ernest Kells - RV-9A O235-N2C, Wood Prop
>> 90 plus % Complete - seat kit arrived today
>>
>>
>>
>>>Essential bus - The transponder has an off switch so why sweat it.
>>>
>>>
>>Bruce
>>
>>
>>>www.glasair.org
>>>
>>> Which bus would you wire the Transponder to, and why?
>>>Charlie Kuss
>>>
>>>
>>
>>
>
> Bob . . .
>
> --------------------------------------------
> ( Knowing about a thing is different than )
> ( understanding it. One can know a lot )
> ( and still understand nothing. )
> ( C.F. Kettering )
> --------------------------------------------
>
>
>
>
________________________________________________________________________________
| From: | Richard May <ram45(at)comporium.net> |
| Subject: | solar battery charger |
I keep my plane in a T hanger that lacks electricity, I've purchased a
couple of solar cell battery chargers from Harbor freight at $10 a piece
andmounted them on the roof of my hanger. They work quite well, except
that they give out after a few months of use. I connect one to the battery
in my plane, and the other to the battery in my small tug to pull the
airplane in and out of the hanger. I just recently read that they will
discharge the battery at night or during cloudy days without a blocking
diode. Does anyone know what type of diode to use for this purpose, and do
I connect it to the positive or negative lead coming from the solar panel?
Is there any type of device I could construct to prevent over-charging of
batteries from Radio shack parts?
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | solar battery charger |
Subject: solar battery charger
From: Richard May (ram45(at)comporium.net)
Date: Fri Oct 17 - 9:38 AM
>I've purchased a couple of solar cell battery chargers from Harbor freight
at $10 a piece
Make sure the cells put out a few volts more than the battery. You can put
the cells in series just like batteries.
>They work quite well, except that they give out after a few months of use.
The Solar cells give out??? They should last forever. If the batteries give
out they are probably suffering from never getting charged.
>I just recently read that they will discharge the battery at night or
during cloudy days
>without a blocking diode. Does anyone know what type of diode to use for
this purpose, and do
>I connect it to the positive or negative lead coming from the solar panel?
Use a 1N4001 to a 1N4007. Doesn't much matter. Use any "General Purpose"
silicon diode.
Attach it to the positive lead with the little silver band away from the
solar cell. You can put it indoor going into the battery positive too.
Little silver band goes towards the battery+.
>Is there any type of device I could construct to prevent over-charging of
>batteries from Radio shack parts?
Yes. First buy a copy of "Forrest Mim's Engineer's Notebook" at Radio Shack
. Then build a LM317 voltage regulator and adjust the output to whatever the
battery's fully charged voltage should be. This won't do the fastest job but
it will work well. You can forget about the diode if you take this route.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"Kitty Hawk Centennial---first heavier-than-air flight that didn't
immediately crash"
________________________________________________________________________________
| Subject: | Re: solar battery charger |
| From: | caspainhower(at)aep.com |
10/17/2003 02:13:13 PM
Does anyone know what type of diode to use for this purpose, and do
I connect it to the positive or negative lead coming from the solar panel?
A schottky diode is most commonly used, they drop ~.2 volts instead of the
~.6 volts of a standard diode. As long as they are properly biased it
shouldn't matter which lead they are in.
Craig S.
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Transponder Main bus or Essential Bus |
>
>:-)
>
>Also, I liked your change of name from "Essential" bus to "Endurance"
>bus... if something is truly essential to continued flight, it should go
>on the battery bus...
>
>-John
It's certainly an advantage to reduce parts count between
an "essential" item and its power source to reduce probability
that use of that item will not be lost. However, if having
but one such "essential" device puts probability of comfortable
completion of flight at risk, then one should have a BACKUP
for it. If every item capable of ruining your day has a BACKUP,
then all of a sudden, it is NOT ESSENTIAL. It changes the way
you can look at system design and truly achieve a system that
is both essential and emergency free.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Strobe wire? |
>
>Check www.strobesnmore.com . He can sell you the Nova power supply and
>cable by the foot. If you're using only 2 strobe heads the XPak 604 will do
>the job for you. I know a lot of folks are using the 904 but with only 2
>heads that power supply (904) reduces the power output. This is not the
>case with the 604. If you're using more than 2 flash tubes it's a mute
>point. Just thought I'd pass it along.
>Bill
>Glasair SIIS-FT
Great data point Bill, thanks!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: 10856 Wandke |
>
>Comments/Questions: Wonder if I can use #4 cable to hook up a firewall
>mounted battery to a Sky Tec starter on a new )235N2C(lower
>compression). Using an Odyssey 680 battery in a Murphy Rebel.
Sure . . . #4 is quite adequate to this task when the
battery and engine are close together.
I will invite you to join us on the AeroElectric List
to continue this and similar discussions. It's useful to
share the information with as many folks as possible.
A further benefit can be realized with membership on
the list. There are lots of technically capable folks
on the list who can offer suggestions too. You can
join at . . .
http://www.matronics.com/subscribe/
Well considered and technically elegant answers to
all of your questions are waiting for you there. Also,
check out the downloadable materials at
http://www.aeroelectric.com
Thanks!
Bob . . .
|---------------------------------------------------|
| A lie can travel half way around the world while |
| the truth is till putting on its shoes . . . |
| -Mark Twain- |
|---------------------------------------------------|
________________________________________________________________________________
| From: | jerb <ulflyer(at)verizon.net> |
| Subject: | Re: Strobe wire? |
Rather than Nyloflo - get some of the light weight 1/2" tubing used for
Mister or drip irrigation systems. One point does it need to be flame
retardant, if so it may not qualify for this application.
jerb
snip....
> Consider this instead. If you buy a Whelan kit, it will come
> with the wire. How about running a conduit of Nyloflo or
> similar tubing from root to tip now. When you get your kit
> later, it will be easy to run the wires in.
>
> ================================
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | thermistors for low fuel warning |
>
> > I'm using a optical device in my Glastar, works great and as it is LED it
> > needs nearly no power!!
> >
> > http://www.ppavionics.com/LFL.htm
>
>$405 per tank ??? there has to be a less expensive way. I'd be interested in
>learning more about that thermistor arrangement.
Consider the Gemssenors p/n 143570 at:
http://www.gemssensors.com/SpecTemplateStandard.asp?nProductGroupID=2
which can be had for $80 each and will drive a 40 ma lamp
directly (plenty good for LED and you can find some 0.04A incandescent
lamps too).
Bob . . .
________________________________________________________________________________
| From: | PTACKABURY(at)aol.com |
| Subject: | Current Limiters |
Bob: Help!! I am building a Lancair IV and am at the wire stringing stage.
I have two 17 amp hour batteries and one 70 amp alternator. I have adopted a
version of your Z-13 for the power distribution architecture, but can't
figure out how many, where and what size current limiters I should use. Part of
the problem is I can't read the diagrams in your book as the small print is
fuzzy (and my eyes are on their sixth decade). So please tell me how to configure
my current limiters. thanks and regards, paul
________________________________________________________________________________
| From: | "Werner Schneider" <wernerschneider(at)compuserve.com> |
| Subject: | Re: thermistors for low fuel warning |
What did you look at, one set is 115$ or 215$ a pair.
Sure you can do it cheaper yourself, just you have to get two indicators
with push to test (doing circuit test), two optical sensors , a circuit
testing when the indicator fails etc. As you can see 4 wires are running
between indicator and sensor for this purpose. Switch on current is a bit
above 40ma, running on a bit over 20 ma for each sensor.
As you've told you can make it cheaper, I found it value worth the money.
It's up to everybody to decide by him/herself.
And no I'm not in any way involved in PPA, just a happy customer =(;o)
Werner
----- Original Message -----
From: "John Slade" <sladerj(at)bellsouth.net>
Subject: RE: AeroElectric-List: thermistors for low fuel warning
>
> > I'm using a optical device in my Glastar, works great and as it is LED
it
> > needs nearly no power!!
> >
> > http://www.ppavionics.com/LFL.htm
>
> $405 per tank ??? there has to be a less expensive way. I'd be interested
in
> learning more about that thermistor arrangement.
> John Slade
>
>
________________________________________________________________________________
| Subject: | Re: Current Limiters |
| From: | "Matt Prather" <mprather(at)spro.net> |
Paul,
You can get fresh copies of all of the diagrams in the appendix
by downloading the following .pdf file:
http://www.aeroelectric.com/articles/Rev10/z10.pdf
Regards,
Matt-
VE N34RD
>
> Bob: Help!! I am building a Lancair IV and am at the wire stringing
> stage. I have two 17 amp hour batteries and one 70 amp alternator. I
> have adopted a version of your Z-13 for the power distribution
> architecture, but can't figure out how many, where and what size
> current limiters I should use. Part of the problem is I can't read the
> diagrams in your book as the small print is fuzzy (and my eyes are on
> their sixth decade). So please tell me how to configure my current
> limiters. thanks and regards, paul
>
>
________________________________________________________________________________
| From: | Joa Harrison <flyasuperseven(at)yahoo.com> |
| Subject: | thermistors for low fuel warning |
Anybody ran across an auto part number for an auto fuel tank?
Joa
---------------------------------
________________________________________________________________________________
| From: | "Trampas" <tstern(at)nc.rr.com> |
| Subject: | thermistors for low fuel warning |
Most of the 90's model Toyotas have them but you will most likely have to
order the entire fuel sending unit, about $280.
On the other hand I found that everything mustang sells the thermistor
sensor for $32
www.everythingmustang.com
Everything Mustang's website is down, I found the price through goggle's
cache.
http://216.239.51.104/search?q=cache:GvfTUJyGVUEJ:www.everythingmustang.com/
Merchant2/merchant.mv%3FScreen%3DCTGY%26Store_Code%3DEM%26Category_Code%3DTH
ERME+low+fuel+light+thermistor&hl=en&ie=UTF-8
Trampas
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Joa
Harrison
Subject: RE: AeroElectric-List: thermistors for low fuel warning
Anybody ran across an auto part number for an auto fuel tank?
Joa
---------------------------------
________________________________________________________________________________
| From: | Tom Brusehaver <cozytom(at)mn.rr.com> |
| Subject: | Re: Transponder Main bus or Essential Bus |
Things could be better, with modern solid state transponders,
but this is something that happened to me, with an older KT-76.
During instrument training, we took off from FCM, in a Beech
Sundowner. It was marginal VFR, and at 3000MSL there was
an overcast.
We were shooting my first approach for the day, VOR 11 at
LVN, when approach called up and said they lost our transponder.
Shocked my instructor said he'd look into it. He turned it
off, then on, then pressed the CB, then fiddled and fiddled
but the response light never came on.
I went missed, called approach, and asked 'em anything
on the transponder? They said nope. Can't well fly
IFR in RADAR environment without a transponder, so
we elected to head back to FCM (about 15min).
During the trip, when the transponder was off, the
ammeter showed almost no charge, with it on, a slight
discharge. I cycled the master once, got about a 10AMP
charge for about 2 seconds, then discharge. Could be the
ammeter never really showed much of a discharge.
Com/Nav Radios continued to work, but no-go on the
transponder. We wouldn't have noticed the dead
alternator, for a while, if approach wouldn't have
told us they lost our transponder.
Leave it on the essential buss, it could be a warning
device if nothing else :-).
Charlie Kuss wrote:
>
> Listers,
> Which bus would you wire the Transponder to, and why?
> Charlie Kuss
>
________________________________________________________________________________
| From: | jerb <ulflyer(at)verizon.net> |
| Subject: | Re: Need for relays? |
In most cases AC voltage/current rated switches normally will only carry a
fraction of their AC rated current when used for DC current
applications. The contacts are made of different material plus they use
the zero crossing of the AC current to reduce contact burning/arcing when
contacts are opened. Example a 5 Amp AC switch may only handle less than
100 mA of DC current. While some have improperly used them and gotten away
with it for the time being, you'll never know when they will fail and fail
prematurely. While AC rated switches may work fine for say for avionics
switching for radios such as mike input or (logical level) feature control
signals, any application carrying any amount of DC current more than 100
mA, use DC rated switches. They may cost a little more but lately I
noticed there is getting to be less difference between the two.
jerb
>
>
> >
> >Bob,
> > Just received plans for an engine install. It shows all switches with
> > #22 wire going to relays (22 Relays). My understanding is that certain
> > heavy loads (Pitot heat etc) need a relay as the switches can't handle
> > the amps. But do I need relays for 3-10 amp circuits? More relays are
> > more components to fail. I have looked at 125v 10 and 15 amp rocker
> > switches from Digikey that look like they can handle the current.
> > Pro/cons? Thanks\
>
> Your switches will probably be just fine directly
> switching the loads. See
> http://www.aeroelectric.com/articles/swtchrat.pdf
>
> Bob . . .
>
>
________________________________________________________________________________
| From: | Jerzy Krasinski <krasinski(at)direcway.com> |
| Subject: | Bob, external power receptacle |
Bob,
I got a receptacle which is used commonly for connection to an external
battery if internal battery is week. I was told that the receptacle is
from a Cessna. I hoped for an easy installation but there are three
prongs there. Two big ones are described "+" (the central one), and
"-" (the side one). Unfortunately, there is a third one, smaller. No
description there, but there are two ~1A diodes connected to it, able
to conduct "from" the prong.
I would like to make the receptacle compatible with battery carts at
airports, so Cessna standard seems to be the right one. But how is the
third prong connected? Is it used to drive a relay or something?
I could not find anything on thet topic. I would appreciate your answer.
Thank you,
Jerzy
Werner Schneider wrote:
>
>Interesting approach, would wonder what happens if you have a fuel injected
>engine with a return line (of "hot" fuel) back into the tanks.
>
>I'm using a optical device in my Glastar, works great and as it is LED it
>needs nearly no power!!
>
>http://www.ppavionics.com/LFL.htm
>
>Werner
>
>----- Original Message -----
>
>
>
>>When the thermistor is immersed in fuel, the fuel keeps the thermistor
>>cooled off, the resistance remains high and the indicator light bulb does
>>not light up.
>>
>>
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Need for relays? |
>
>In most cases AC voltage/current rated switches normally will only carry a
>fraction of their AC rated current when used for DC current
>applications. The contacts are made of different material plus they use
>the zero crossing of the AC current to reduce contact burning/arcing when
>contacts are opened. Example a 5 Amp AC switch may only handle less than
>100 mA of DC current.
Not so. Relays are only slightly different than toggle
switches in that their contact spreading velocities are
not enhanced with over-center springs . . . but the ratio
is not so great that any 5A relay needs to be de0rated
to 100 ma. See
> While some have improperly used them and gotten away
>with it for the time being, you'll never know when they will fail and fail
>prematurely. While AC rated switches may work fine for say for avionics
>switching for radios such as mike input or (logical level) feature control
>signals, any application carrying any amount of DC current more than 100
>mA, use DC rated switches. They may cost a little more but lately I
>noticed there is getting to be less difference between the two.
. . . simply not supported by engineering data from
switch and relay manufacturers. See
http://www.aeroelectric.com/articles/swtchrat.pdf
for an exploration of switches . . . relays are
not terribly different.
If any one can cite manufacturer's data sheets for
any control product be it switch or relay that
suggests an AC/DC de-rating ratio this severe, I'd
like to get a copy of it. Much of what's being
circulated as valid common knowledge has roots
in the RVator article I cited in my piece on
switch ratings. The author badly mis-interpreted
the Microswitch data sheets. These seeds have
grown into forests of electro-whizzy folklore.
The question that started this thread was posted by a reader
who was pondering an airframe wiring diagram suggested by
an engine supplier wherein the panel was sprinkled with
something on the order of 20 switches all driving relays
used to actually control loads.
There is simply no justification for doing this. It drives
parts count up, cost up, reliability down, and offers
little if any useful improvement in performance. This
system was crafted with little or no practical
knowledge of designing for the elegant solution.
So far, I've only seen photos of installed equipment.
I'm waiting to see the remainder of the documentation
before we attempt to comb the rats and tangles out
of this badly over-built system.
Bob . . .
________________________________________________________________________________
| From: | kempthornes <kempthornes(at)earthlink.net> |
| Subject: | Re: Need for relays? |
>
>In most cases AC voltage/current rated switches normally will only carry a
>fraction of their AC rated current when used for DC current
>applications.
I've been turning my electric fuel pump on and off with a micro toggle
switch rated for AC with no explosions yet. Any day now tho, eh?
>The contacts are made of different material plus they use
>the zero crossing of the AC current to reduce contact burning/arcing
My wife has so much trouble catching that brief little zero crossing that
she just leaves lights on all over the house.
K. H. (Hal) Kempthorne
RV6-a N7HK - Three trips to OSH now.
PRB (El Paso de Robles, CA)
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: External power receptacle |
From Najaco.com
CESSNA "GROUND SERVICE PLUG RECEPTACLE
A ground service plug receptacle permits the use of an external power source
for cold-weather starting and during lengthy maintenance work on the
electrical and avionics equipment. External power control circuitry is
provided to prevent the external power and battery from being connected
together during starting. The external power receptacle is installed on the
left side of the engine compartment near the firewall.
The ground service circuit incorporates polarity reversal and overvoltage
protection. Power from the external power source will flow only if the
ground service plug is correctly connected to the airplane. If the plug is
accidentally connected backwards or the ground service voltage is too high,
no power will flow to the electrical system, thereby preventing any damage
to electrical equipment."
So the center pin is also positive but with a diode or so to be read by the
ground power unit.
Eric
________________________________________________________________________________
| From: | Jeff Deuchar <jdeuchar(at)telusplanet.net> |
Hello,
I have a question about AWG.
If I parallel two 26 AWG wires, what size of wire do I end up with?
The reason I ask this strange question, is that I can get my hands on plenty of
26 guage wire, and was thinking I could pair it up?
Thanks
Jeff
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Bob, external power receptacle |
>
>
>Bob,
>I got a receptacle which is used commonly for connection to an external
>battery if internal battery is week. I was told that the receptacle is
>from a Cessna. I hoped for an easy installation but there are three
>prongs there. Two big ones are described "+" (the central one), and
>"-" (the side one). Unfortunately, there is a third one, smaller. No
>description there, but there are two ~1A diodes connected to it, able
>to conduct "from" the prong.
There are two commonly used ground power receptacles in the
wild. One is a Cole-Hersey product designed for over the road
trucks and adapted to aircraft by Piper about 40 years ago.
It's has be popularized as the "Piper style ground power jack."
This is a simple, cylinder with outside shell as ground, and
a single robust center pin as power.
In the years BP (before Piper) the military and air transport
communities developed a three terminal plug/socket combination
which you have described. It's a military standard part used
on many ground and air vehicle applications and is the connector
of choice for most aircraft.
>I would like to make the receptacle compatible with battery carts at
>airports, so Cessna standard seems to be the right one. But how is the
>third prong connected? Is it used to drive a relay or something?
Consider what happens if you make or break a high current
connection while energized. There is bound to be arcing that
ultimately damages the contacts of the connector. The third
pin is smaller (is sized only for mechanical robustness and
carries only a few amps in operation) and shorter (connects
AFTER the big guys are hooked up and disconnects BEFORE
the big guys do). This pin is used to control a ground power
contactor in the in a manner that makes sure that
power cannot flow through the big pins while the connector
is being mated or de-mated. Originally, this was the ONLY
purpose for the small pin.
Other features have been added over the years to include
some components for ov and reverse polarity protection.
I have illustrated wiring for both the Piper style and
military style ground power jacks in an article at:
http://www.aeroelectric.com/articles/grndpwr.pdf
If it were my airplane, I'd go the "Piper" route.
The military style is a pain in the arse to install.
You need to fabricate your own door or mount it
someplace where a door is not needed. The Piper
style comes with its own door built in, is much
easier to install, and probably lighter than
the 3-pin connector installation.
Another advantage of the Cole-Hersey connector
is that you can have your own ground power jumper
cables made up and it two is lighter than one
using the fatter military style connector and
a LOT less expensive.
Bob . . .
>I could not find anything on thet topic. I would appreciate your answer.
>Thank you,
>Jerzy
>
>Werner Schneider wrote:
>
>
> >
> >Interesting approach, would wonder what happens if you have a fuel injected
> >engine with a return line (of "hot" fuel) back into the tanks.
> >
> >I'm using a optical device in my Glastar, works great and as it is LED it
> >needs nearly no power!!
> >
> >http://www.ppavionics.com/LFL.htm
> >
> >Werner
> >
> >----- Original Message -----
> >
> >
> >
> >>When the thermistor is immersed in fuel, the fuel keeps the thermistor
> >>cooled off, the resistance remains high and the indicator light bulb does
> >>not light up.
> >>
> >>
> >
> >
> >
> >
>
>
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| From: | "Bob Kuc" <bkuc1(at)tampabay.rr.com> |
| Subject: | Re: thermistors for low fuel warning |
>
> Most of the 90's model Toyotas have them but you will most likely have to
> order the entire fuel sending unit, about $280.
>
> On the other hand I found that everything mustang sells the thermistor
> sensor for $32
> www.everythingmustang.com
>
I was following this approach one time ago. I went to a U-pull-it yard, and
looked for all the import dashes for the low-level fuel light, and a fuel
tank still there. With four bolts, and a philips, I dropped the tank and
opened up the cover and removed the sensor. I ended pickup up three in one
morning. $1 to get into the yard and the cost of the sensors, well,
priceless.
At one time, there were low level optical that were sold in the us. Can't
remember the manufacturer. However, they discontinued them for another
approach that would not work. However, I did pick up a few liquid level
sensors from Australia via an "exchange" between builders. I am planning on
using these refract low level sensors on my sump tanks.
Bob
---
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>
>Hello,
>
>I have a question about AWG.
>
>If I parallel two 26 AWG wires, what size of wire do I end up with?
Wire cross-section doubles/halves for each three steps in AWG
size. For example, 22AWG wire is 1/4 the cross section of 16AWG
(6 steps away). As far as current carrying ability, there's a tiny
advantage for say 3 22AWG wires carrying current as opposed to one
19AWG wire . . . the three wires dump heat better than a single
strand of the same cross-section.
>The reason I ask this strange question, is that I can get my hands on
>plenty of
>26 guage wire, and was thinking I could pair it up?
Please don't do this. Wire is a trivial part of the expense
of building your airplane. You have a lot of new things to learn
in the proper use of tools and materials to do a good job.
Some years from now, you're going to want to sell your airplane
and it's my wish that you'll be proud of what you're offering
to the next owner.
Bob . . .
________________________________________________________________________________
| From: | "Robinson, Chad" <crobinson(at)rfgonline.com> |
AWG sizes are biased on wire DIAMETER so you don't double that, as you can guess.
Assuming a "perfect" wire, you get roughly the same resistance in both wires. The
total resistance is 1/Rt = 1/(R1+R2), which for two identically-sized resistors
(perfect wire) gives you half the initial resistance. That's gives you double
the current capacity - about what you'd expect.
My AWG table gives various current capacities depending on insulator type, number
of strands, etc., which all affect heat dissipation. But if I take the lowest
number I have 4A for one wire, and if I look for an 8A wire I get 22AWG.
There are a few problems, of course. Because of the insulation the wires will be
larger, so they might be harder to feed through a hole. You have to be careful
about fusing because if either wire breaks or is cut somehow (or just not solidly
terminated), you're actually protecting a 26AWG wire again, with only 4A
of capacity, so it's easier to create situations where the wire gets too hot
and starts a fire. Finally, because there's no such thing as a perfect wire (heck,
even if you measure carefully the lengths might not be the same) one wire
might carry more current than another (lower resistance) so you should probably
"derate" their capacity a bit - maybe to 7.5A. (Actually it's nowhere near
that much for short runs but...)
Unless you have some vested reason to do so (such as if those wires are already
run, and you're repurposing two of them to carry the current you need) you'd
be better off with a single wire. Not to mention the complexity this creates in
your wiring diagram. But there ARE valid reasons to do this and it CAN work
if you're careful.
Did I mess any of this up, Bob?
Regards,
Chad
> -----Original Message-----
> From: Jeff Deuchar [mailto:jdeuchar(at)telusplanet.net]
> Sent: Saturday, October 18, 2003 9:58 AM
> To: aeroelectric-list(at)matronics.com
> Subject: AeroElectric-List: AWG
>
> I have a question about AWG.
>
> If I parallel two 26 AWG wires, what size of wire do I end up with?
>
> The reason I ask this strange question, is that I can get my
> hands on plenty of
> 26 guage wire, and was thinking I could pair it up?
________________________________________________________________________________
| From: | Carl Coulter <coulter(at)gci.net> |
| Subject: | RE: solar battery charger |
Richard
There are problems with just using a blocking diode, mainly over charging.
I don't know what Harbor is selling. From your description, it is a kit for
keeping bats charged and one would expect there to be a charge controller
and blocking diode included. Should be, but then, for $10, maybe not.
Could be the Harbor PV cells are small enough they can't overcharge the bat.
In that case, the suggestions in the other replies for a diode are good
ones.
I would highly recommend a charge controller between the pv cells and the
battery. The controller watches the battery voltage and shuts off the
charge when the bat is full. All of the ones I have seen have a blocking
diode in the circuit to prevent discharge when the cells are not putting out
sufficient voltage - like every night. Also, some cells have a blocking
diode at the cell. The cells I bought 5 years ago did. In my case, I wired
around the diode in the cells cause I did not want the additional .6V drop,
and the charge controller took care of any backfeed.
There are a lot of controllers on the market. Most any outfit that deals
with solar cells for remote cabins, RV, or marine applications have this
stuff. They come in all sizes, complexity, and price. I bought a couple of
pretty inexpensive ones for a cabin about three years ago and as I recall
they were $20 or so. These were pretty dumb; three terminal potted device,
no bat voltage adjustment.
Try a Google search: solar cells charge controllers RV OR marine. I got
about 8,000 hits. Most will be way to big for your application. But, there
are small (read "inexpensive") units available.
This one was $30 at http://www.oksolar.com/charge_controllers/sunsaver.htm
Item#: 34931
SG4
Manufacturer: MorningStar
12VDC, 4.5A
More Info
$29.95
I'm not recommending it, it was just the first one I saw that looked like it
would fit.
I also don't know what size pv cell Harbor is selling. I would think the
minimum you will need is 10 watts - that would be .6 Amps. Most are rated
for available sun at noon-in June-in Arizona, so you won't even get that
most days, but that would be a minimum. My guess is the cell will be 12" to
14" square to get that output. The guess is based on a statistical sample
of one. The ones I bought five years ago are rated at 50W and are about 14"
X 48".
A lot of these sites will also have battery charging kits (pv cell and
controller) available. But for 10+ watts, I think they will be in the
$100 - $200 range.
Building a system is feasible. You will need a blocking diode, voltage
regulator, and bat voltage sensing - oh yeah, and a big enough cell. The
trick is to keep the energy budget for the controller low, especially when
the cells are off line. Solar cell applications generally don't have any
energy to waste and the blocking diode may not stop all of the discharge
(the voltage sensing circuit). Of course, one could put the sensing circuit
on the controller side of the blocking diode and just compensate for the
drop.
Also, some of the current production controllers have a pulsed output. This
supposedly makes the charger more efficient. These get more complicated.
One has to measure the bat voltage between pulses. It takes a couple of
bucks worth of silicon (microprocessor). This is out of my area of design
expertise.
I can probably do an 8.5X11 pencil sketch with a list of RS parts - no
pulsed output, and it might even work. But, I'll bet Eric is your man for
this. (You're welcome Eric ;-)
I think you have a good idea. Happy charging and I hope you don't get gas
;-)
(bad electrical engineering joke)
Carl (haven't worked on my cabin in three years - airplane kit keeps sucking
up the time)
**********************
From: Richard May <ram45(at)comporium.net>
Subject: AeroElectric-List: solar battery charger
I keep my plane in a T hanger that lacks electricity, I've purchased a
couple of solar cell battery chargers from Harbor freight at $10 a piece
andmounted them on the roof of my hanger. They work quite well, except
that they give out after a few months of use. I connect one to the battery
in my plane, and the other to the battery in my small tug to pull the
airplane in and out of the hanger. I just recently read that they will
discharge the battery at night or during cloudy days without a blocking
diode. Does anyone know what type of diode to use for this purpose, and do
I connect it to the positive or negative lead coming from the solar panel?
Is there any type of device I could construct to prevent over-charging of
batteries from Radio shack parts?
________________________________ Message 11
____________________________________
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: AeroElectric-List: solar battery charger
Subject: solar battery charger
From: Richard May (ram45(at)comporium.net)
>I've purchased a couple of solar cell battery chargers from Harbor freight
at $10 a piece
Make sure the cells put out a few volts more than the battery. You can put
the cells in series just like batteries.
>They work quite well, except that they give out after a few months of use.
The Solar cells give out??? They should last forever. If the batteries give
out they are probably suffering from never getting charged.
>I just recently read that they will discharge the battery at night or
during cloudy days
>without a blocking diode. Does anyone know what type of diode to use for
this purpose, and do
>I connect it to the positive or negative lead coming from the solar panel?
Use a 1N4001 to a 1N4007. Doesn't much matter. Use any "General Purpose"
silicon diode.
Attach it to the positive lead with the little silver band away from the
solar cell. You can put it indoor going into the battery positive too.
Little silver band goes towards the battery+.
>Is there any type of device I could construct to prevent over-charging of
>batteries from Radio shack parts?
Yes. First buy a copy of "Forrest Mim's Engineer's Notebook" at Radio Shack
. Then build a LM317 voltage regulator and adjust the output to whatever the
battery's fully charged voltage should be. This won't do the fastest job but
it will work well. You can forget about the diode if you take this route.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"Kitty Hawk Centennial---first heavier-than-air flight that didn't
immediately crash"
________________________________ Message 12
____________________________________
Subject: Re: AeroElectric-List: solar battery charger
From: caspainhower(at)aep.com
10/17/2003 02:13:13 PM
Does anyone know what type of diode to use for this purpose, and do
I connect it to the positive or negative lead coming from the solar panel?
A schottky diode is most commonly used, they drop ~.2 volts instead of the
~.6 volts of a standard diode. As long as they are properly biased it
shouldn't matter which lead they are in.
Craig S.
________________________________ Message 13
____________________________________
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Transponder Main bus or Essential Bus
<jrourke@allied-computer.com>
>
>:-)
>
>Also, I liked your change of name from "Essential" bus to "Endurance"
>bus... if something is truly essential to continued flight, it should go
>on the battery bus...
>
>-John
It's certainly an advantage to reduce parts count between
an "essential" item and its power source to reduce probability
that use of that item will not be lost. However, if having
but one such "essential" device puts probability of comfortable
completion of flight at risk, then one should have a BACKUP
for it. If every item capable of ruining your day has a BACKUP,
then all of a sudden, it is NOT ESSENTIAL. It changes the way
you can look at system design and truly achieve a system that
is both essential and emergency free.
Bob . . .
________________________________ Message 14
____________________________________
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Re: Strobe wire?
>
>Check www.strobesnmore.com . He can sell you the Nova power supply and
>cable by the foot. If you're using only 2 strobe heads the XPak 604 will
do
>the job for you. I know a lot of folks are using the 904 but with only 2
>heads that power supply (904) reduces the power output. This is not the
>case with the 604. If you're using more than 2 flash tubes it's a mute
>point. Just thought I'd pass it along.
>Bill
>Glasair SIIS-FT
Great data point Bill, thanks!
Bob . . .
________________________________ Message 15
____________________________________
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: AeroElectric-List: Re: 10856 Wandke
>
>Comments/Questions: Wonder if I can use #4 cable to hook up a firewall
>mounted battery to a Sky Tec starter on a new )235N2C(lower
>compression). Using an Odyssey 680 battery in a Murphy Rebel.
Sure . . . #4 is quite adequate to this task when the
battery and engine are close together.
I will invite you to join us on the AeroElectric List
to continue this and similar discussions. It's useful to
share the information with as many folks as possible.
A further benefit can be realized with membership on
the list. There are lots of technically capable folks
on the list who can offer suggestions too. You can
join at . . .
http://www.matronics.com/subscribe/
Well considered and technically elegant answers to
all of your questions are waiting for you there. Also,
check out the downloadable materials at
http://www.aeroelectric.com
Thanks!
Bob . . .
|---------------------------------------------------|
| A lie can travel half way around the world while |
| the truth is till putting on its shoes . . . |
| -Mark Twain- |
|---------------------------------------------------|
________________________________ Message 16
____________________________________
From: jerb <ulflyer(at)verizon.net>
Subject: Re: AeroElectric-List: Re: Strobe wire?
Rather than Nyloflo - get some of the light weight 1/2" tubing used for
Mister or drip irrigation systems. One point does it need to be flame
retardant, if so it may not qualify for this application.
jerb
snip....
> Consider this instead. If you buy a Whelan kit, it will come
> with the wire. How about running a conduit of Nyloflo or
> similar tubing from root to tip now. When you get your kit
> later, it will be easy to run the wires in.
>
> ================================
________________________________ Message 17
____________________________________
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: RE: AeroElectric-List: thermistors for low fuel warning
>
> > I'm using a optical device in my Glastar, works great and as it is LED
it
> > needs nearly no power!!
> >
> > http://www.ppavionics.com/LFL.htm
>
>$405 per tank ??? there has to be a less expensive way. I'd be interested
in
>learning more about that thermistor arrangement.
Consider the Gemssenors p/n 143570 at:
http://www.gemssensors.com/SpecTemplateStandard.asp?nProductGroupID=2
which can be had for $80 each and will drive a 40 ma lamp
directly (plenty good for LED and you can find some 0.04A incandescent
lamps too).
Bob . . .
________________________________ Message 18
____________________________________
From: PTACKABURY(at)aol.com
Subject: AeroElectric-List: Current Limiters
Bob: Help!! I am building a Lancair IV and am at the wire stringing stage.
I have two 17 amp hour batteries and one 70 amp alternator. I have adopted
a
version of your Z-13 for the power distribution architecture, but can't
figure out how many, where and what size current limiters I should use.
Part of
the problem is I can't read the diagrams in your book as the small print is
fuzzy (and my eyes are on their sixth decade). So please tell me how to
configure
my current limiters. thanks and regards, paul
________________________________ Message 19
____________________________________
From: "Werner Schneider" <wernerschneider(at)compuserve.com>
Subject: Re: AeroElectric-List: thermistors for low fuel warning
What did you look at, one set is 115$ or 215$ a pair.
Sure you can do it cheaper yourself, just you have to get two indicators
with push to test (doing circuit test), two optical sensors , a circuit
testing when the indicator fails etc. As you can see 4 wires are running
between indicator and sensor for this purpose. Switch on current is a bit
above 40ma, running on a bit over 20 ma for each sensor.
As you've told you can make it cheaper, I found it value worth the money.
It's up to everybody to decide by him/herself.
And no I'm not in any way involved in PPA, just a happy customer =(;o)
Werner
----- Original Message -----
From: "John Slade" <sladerj(at)bellsouth.net>
Subject: RE: AeroElectric-List: thermistors for low fuel warning
>
> > I'm using a optical device in my Glastar, works great and as it is LED
it
> > needs nearly no power!!
> >
> > http://www.ppavionics.com/LFL.htm
>
> $405 per tank ??? there has to be a less expensive way. I'd be interested
in
> learning more about that thermistor arrangement.
> John Slade
>
>
________________________________ Message 20
____________________________________
Subject: Re: AeroElectric-List: Current Limiters
From: "Matt Prather" <mprather(at)spro.net>
Paul,
You can get fresh copies of all of the diagrams in the appendix
by downloading the following .pdf file:
http://www.aeroelectric.com/articles/Rev10/z10.pdf
Regards,
Matt-
VE N34RD
>
> Bob: Help!! I am building a Lancair IV and am at the wire stringing
> stage. I have two 17 amp hour batteries and one 70 amp alternator. I
> have adopted a version of your Z-13 for the power distribution
> architecture, but can't figure out how many, where and what size
> current limiters I should use. Part of the problem is I can't read the
> diagrams in your book as the small print is fuzzy (and my eyes are on
> their sixth decade). So please tell me how to configure my current
> limiters. thanks and regards, paul
>
>
________________________________ Message 21
____________________________________
From: Joa Harrison <flyasuperseven(at)yahoo.com>
Subject: RE: AeroElectric-List: thermistors for low fuel warning
Anybody ran across an auto part number for an auto fuel tank?
Joa
---------------------------------
________________________________ Message 22
____________________________________
From: "Trampas" <tstern(at)nc.rr.com>
Subject: RE: AeroElectric-List: thermistors for low fuel warning
Most of the 90's model Toyotas have them but you will most likely have to
order the entire fuel sending unit, about $280.
On the other hand I found that everything mustang sells the thermistor
sensor for $32
www.everythingmustang.com
Everything Mustang's website is down, I found the price through goggle's
cache.
http://216.239.51.104/search?q=cache:GvfTUJyGVUEJ:www.everythingmustang.com/
Merchant2/merchant.mv%3FScreen%3DCTGY%26Store_Code%3DEM%26Category_Code%3DTH
ERME+low+fuel+light+thermistor&hl=en&ie=UTF-8
Trampas
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Joa
Harrison
Subject: RE: AeroElectric-List: thermistors for low fuel warning
Anybody ran across an auto part number for an auto fuel tank?
Joa
---------------------------------
________________________________ Message 23
____________________________________
From: Tom Brusehaver <cozytom(at)mn.rr.com>
Subject: Re: AeroElectric-List: Transponder Main bus or Essential Bus
Things could be better, with modern solid state transponders,
but this is something that happened to me, with an older KT-76.
During instrument training, we took off from FCM, in a Beech
Sundowner. It was marginal VFR, and at 3000MSL there was
an overcast.
We were shooting my first approach for the day, VOR 11 at
LVN, when approach called up and said they lost our transponder.
Shocked my instructor said he'd look into it. He turned it
off, then on, then pressed the CB, then fiddled and fiddled
but the response light never came on.
I went missed, called approach, and asked 'em anything
on the transponder? They said nope. Can't well fly
IFR in RADAR environment without a transponder, so
we elected to head back to FCM (about 15min).
During the trip, when the transponder was off, the
ammeter showed almost no charge, with it on, a slight
discharge. I cycled the master once, got about a 10AMP
charge for about 2 seconds, then discharge. Could be the
ammeter never really showed much of a discharge.
Com/Nav Radios continued to work, but no-go on the
transponder. We wouldn't have noticed the dead
alternator, for a while, if approach wouldn't have
told us they lost our transponder.
Leave it on the essential buss, it could be a warning
device if nothing else :-).
Charlie Kuss wrote:
>
> Listers,
> Which bus would you wire the Transponder to, and why?
> Charlie Kuss
>
________________________________ Message 24
____________________________________
From: jerb <ulflyer(at)verizon.net>
Subject: Re: AeroElectric-List: Need for relays?
In most cases AC voltage/current rated switches normally will only carry a
fraction of their AC rated current when used for DC current
applications. The contacts are made of different material plus they use
the zero crossing of the AC current to reduce contact burning/arcing when
contacts are opened. Example a 5 Amp AC switch may only handle less than
100 mA of DC current. While some have improperly used them and gotten away
with it for the time being, you'll never know when they will fail and fail
prematurely. While AC rated switches may work fine for say for avionics
switching for radios such as mike input or (logical level) feature control
signals, any application carrying any amount of DC current more than 100
mA, use DC rated switches. They may cost a little more but lately I
noticed there is getting to be less difference between the two.
jerb
>
>
> >
> >Bob,
> > Just received plans for an engine install. It shows all switches
with
> > #22 wire going to relays (22 Relays). My understanding is that certain
> > heavy loads (Pitot heat etc) need a relay as the switches can't handle
> > the amps. But do I need relays for 3-10 amp circuits? More relays are
> > more components to fail. I have looked at 125v 10 and 15 amp rocker
> > switches from Digikey that look like they can handle the current.
> > Pro/cons? Thanks\
>
> Your switches will probably be just fine directly
> switching the loads. See
> http://www.aeroelectric.com/articles/swtchrat.pdf
>
> Bob . . .
>
>
________________________________ Message 25
____________________________________
From: Jerzy Krasinski <krasinski(at)direcway.com>
Subject: AeroElectric-List: Bob, external power receptacle
Bob,
I got a receptacle which is used commonly for connection to an external
battery if internal battery is week. I was told that the receptacle is
from a Cessna. I hoped for an easy installation but there are three
prongs there. Two big ones are described "+" (the central one), and
"-" (the side one). Unfortunately, there is a third one, smaller. No
description there, but there are two ~1A diodes connected to it, able
to conduct "from" the prong.
I would like to make the receptacle compatible with battery carts at
airports, so Cessna standard seems to be the right one. But how is the
third prong connected? Is it used to drive a relay or something?
I could not find anything on thet topic. I would appreciate your answer.
Thank you,
Jerzy
Werner Schneider wrote:
>
>Interesting approach, would wonder what happens if you have a fuel injected
>engine with a return line (of "hot" fuel) back into the tanks.
>
>I'm using a optical device in my Glastar, works great and as it is LED it
>needs nearly no power!!
>
>http://www.ppavionics.com/LFL.htm
>
>Werner
>
>----- Original Message -----
>
>
>>When the thermistor is immersed in fuel, the fuel keeps the thermistor
>>cooled off, the resistance remains high and the indicator light bulb does
>>not light up.
>>
>>
>
>
________________________________ Message 26
____________________________________
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Need for relays?
>
>In most cases AC voltage/current rated switches normally will only carry a
>fraction of their AC rated current when used for DC current
>applications. The contacts are made of different material plus they use
>the zero crossing of the AC current to reduce contact burning/arcing when
>contacts are opened. Example a 5 Amp AC switch may only handle less than
>100 mA of DC current.
Not so. Relays are only slightly different than toggle
switches in that their contact spreading velocities are
not enhanced with over-center springs . . . but the ratio
is not so great that any 5A relay needs to be de0rated
to 100 ma. See
> While some have improperly used them and gotten away
>with it for the time being, you'll never know when they will fail and fail
>prematurely. While AC rated switches may work fine for say for avionics
>switching for radios such as mike input or (logical level) feature control
>signals, any application carrying any amount of DC current more than 100
>mA, use DC rated switches. They may cost a little more but lately I
>noticed there is getting to be less difference between the two.
. . . simply not supported by engineering data from
switch and relay manufacturers. See
http://www.aeroelectric.com/articles/swtchrat.pdf
for an exploration of switches . . . relays are
not terribly different.
If any one can cite manufacturer's data sheets for
any control product be it switch or relay that
suggests an AC/DC de-rating ratio this severe, I'd
like to get a copy of it. Much of what's being
circulated as valid common knowledge has roots
in the RVator article I cited in my piece on
switch ratings. The author badly mis-interpreted
the Microswitch data sheets. These seeds have
grown into forests of electro-whizzy folklore.
The question that started this thread was posted by a reader
who was pondering an airframe wiring diagram suggested by
an engine supplier wherein the panel was sprinkled with
something on the order of 20 switches all driving relays
used to actually control loads.
There is simply no justification for doing this. It drives
parts count up, cost up, reliability down, and offers
little if any useful improvement in performance. This
system was crafted with little or no practical
knowledge of designing for the elegant solution.
So far, I've only seen photos of installed equipment.
I'm waiting to see the remainder of the documentation
before we attempt to comb the rats and tangles out
of this badly over-built system.
Bob . . .
________________________________ Message 27
____________________________________
From: kempthornes <kempthornes(at)earthlink.net>
Subject: Re: AeroElectric-List: Need for relays?
>
>In most cases AC voltage/current rated switches normally will only carry a
>fraction of their AC rated current when used for DC current
>applications.
I've been turning my electric fuel pump on and off with a micro toggle
switch rated for AC with no explosions yet. Any day now tho, eh?
>The contacts are made of different material plus they use
>the zero crossing of the AC current to reduce contact burning/arcing
My wife has so much trouble catching that brief little zero crossing that
she just leaves lights on all over the house.
K. H. (Hal) Kempthorne
RV6-a N7HK - Three trips to OSH now.
PRB (El Paso de Robles, CA)
________________________________________________________________________________
| From: | "Steve Sampson" <SSampson.SLN21(at)london.edu> |
Bob - I have looked back through the archives to see what diodes you
reccomend and where to source them for the master / starter solenoids etc..
The IN4005 series at Radio Shack appears. Unfortunately, in the UK, Radio
Shack is considerably less useful than ice skates in the Sahara.
I have looked through the Farnell catalogue to see something that seems
appropriate. Would the ST part BZW06-31 fit the bill? Sorry to ask such
mundane questions.
Steve.
RV9a
UK
________________________________________________________________________________
| From: | "Dan Checkoway" <dan(at)rvproject.com> |
| Subject: | Re: RV-List: 4 conductor shielded wire for Dynon |
I never saw a response to this, and I'm just getting caught up on email...
Dynon told me that the wires to the remote compass do NOT need to be
shielded. In fact, they said it would be fine to use the shield of a
shielded 3 conductor wire as the 4th conductor. That's from the horse's
mouth.
)_( Dan
RV-7 N714D
http://www.rvproject.com
----- Original Message -----
From: "Jeff Point" <jpoint(at)mindspring.com>
Subject: Re: AeroElectric-List: Re: RV-List: 4 conductor shielded wire for
Dynon
>
> I just re-read the recently released, updated version of the
> installation manual. It makes no reference to using shielded wire in
> any part of the installation. I used 4 wire, 22ga shielded because I
> was lucky enough to have some laying around. I would also like to know
> if shielded wire is neccesary or even useful in this installation.
>
> Jeff Point
> RV-6 panel, wiring
> Milwaukee, WI
>
> Larry Bowen wrote:
>
> >
> >So should it be assumed that the harness to the compass MUST be
> >shielded? My harness was completed a couple months ago, but the compass
> >(and radios) are not installed yet. Can I test if this is needed using
> >the handheld? What would the procedure be?
> >
> >-
> >Larry Bowen
> >Larry(at)BowenAero.com
> >http://BowenAero.com
> >
> >
> >
> >
> >>-----Original Message-----
> >>From: Sam Buchanan [mailto:sbuc(at)hiwaay.net]
> >>Sent: Friday, October 03, 2003 3:55 PM
> >>To: rv-list(at)matronics.com
> >>Subject: AeroElectric-List: Re: RV-List: 4 conductor shielded
> >>wire for Dynon
> >>
> >>
> >>
> >>
> >>
> >>DJB6A(at)cs.com wrote:
> >>
> >>
> >>>--> RV-List message posted by: DJB6A(at)cs.com
> >>>
> >>>To all,
> >>>
> >>>For those of you (like me) who have been searching for 4
> >>>
> >>>
> >>conductor 22
> >>
> >>
> >>>gauge shielded wire for your remote mounted Dynon
> >>>
> >>>
> >>Magnetometer, Wicks
> >>
> >>
> >>>aircraft has special ordered 500 ft. You will need to let
> >>>
> >>>
> >>them know it
> >>
> >>
> >>>is not in the catalogue. They expect it in next week. They
> >>>
> >>>
> >>will add it
> >>
> >>
> >>>as a permanent item if there is a demand for it.
> >>>
> >>>Regards,
> >>>Dave Burnham
> >>>RV6A (N64FN)
> >>>
> >>>
> >>Be sure you check your local electrical cable suppliers. I
> >>found a nearby outlet that had the four conductor 22g
> >>shielded cable for $0.45/ft.
> >>
> >>Sam Buchanan
> >>
> >>
> >
> >
> >
> >
>
>
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
I hope Bob doesn't mind my butting in.
Steve: Remarkably, the ST BZW06-31 won't do.
Farnell in the UK (Newark in the US) has billions and billions of 1N4005. If
they are sold out use a 1N4004, or 5, or 6, or 7. Easy to get. By the Way
that's ONE-N4004!
The brief specs you need are: Diode, Rectifier, General Purpose, Case DO-41
(or just anything with leads), Current 1A (minimum), Reverse voltage, 50V
(minimum...get the 100V). Don't let the choices baffle you. We live in a
world of bewildering abundance.
Eric
________________________________________________________________________________
| From: | Jim Sower <canarder(at)frontiernet.net> |
| Subject: | Re: thermistors for low fuel warning |
Bob,
How do you connect them, say, to light a little Radio Shack LED on the panel?
Is it easy, or do you have to know something and do something besides connect
them all in series?
Inquiring minds need to know .... Jim S.
Bob Kuc wrote:
> With four bolts, and a philips, I dropped the tank and
> opened up the cover and removed the sensor. I ended pickup up three in one
> morning. $1 to get into the yard and the cost of the sensors, well,
> priceless.
________________________________________________________________________________
| From: | "Bob Kuc" <bkuc1(at)tampabay.rr.com> |
| Subject: | Re: thermistors for low fuel warning |
Jim,
I bench tested these sensors. You feed them 12 volts. When they are in
fuel the resistance is so high that the LED will not light. When it is out
of fuel the led lights up. It has been a while, I do not remember if I had
a resister in line or not. I do not believe so. It should be easy to test.
Just get a jar of fuel and with a volt meter, you can see how much you get
out.
As a side note. IF one of those sensors are in the bottom of the fuel tank
or in the sump, and the sensor is in water, there is some voltage, but not
as mush as fuel, that goes through the sensor and dimly lights the led, so
one could be used as a water detector. Again, just filling a jar up with
fuel and then adding water, you could check the voltage.
As I write this, it could be that at the time I was testing this, I was
using the lights that were on the dashboard of the cars. So they could be
12v lamps instead of LEDS. If that would be the case, then a resistor would
be needed. You could also probably feed them 5 volts though those sensors
also.
Bob
The liquid sensors that I plan on using on the sumps were made by Honeywell,
but again they are not made in the US. For my fuel tank, I am planning on
putting a T in the hose from the main to my sumps. This T would act like a
standpipe that I can attach a variable voltage fuel sensor. All this will
be attached to a PIC that would interpret the voltages or the on/off of the
optical fuel level sensor and light up the appropriate level bar graph.
> How do you connect them, say, to light a little Radio Shack LED on the
panel?
> Is it easy, or do you have to know something and do something besides
connect
> them all in series?
>
> > With four bolts, and a philips, I dropped the tank and
> > opened up the cover and removed the sensor. I ended pickup up three in
one
> > morning. $1 to get into the yard and the cost of the sensors, well,
> > priceless.
---
________________________________________________________________________________
| From: | flmike <flmike2001(at)yahoo.com> |
| Subject: | Re: ProCrimper II Dies / Question |
Dwight,
For the BNC's, I believe you want die set, p/n
58436-1. That should give you a nice hex crimp for
RG-58 or RG-142 coax. Think it's $42 at Digikey. If
you want an "O" style crimp, the p/n is 58435-1. The
82074 number you mentioned is the coax connector
catalog.
For the machined D-sub pins, I'd go with the four-way
crimp tool that B & C or one of the other suppliers
sells rather than a die set for the Pro-Crimper. Or a
Daniels AFM8 with the right positioner if you can find
one cheap.
The other die set you might want for the Pro-Crimper
is one for the Amp / Tyco Mate-n-loc pins used on the
strobe connectors. That would be die set p/n 90575-2.
But, this die set is NOT cheap, like $100. Hard to
justify for one project, but it does make a beautiful
crimp.
Mike
__________________________________
________________________________________________________________________________
| From: | "Steve Sampson" <SSampson.SLN21(at)london.edu> |
Eric - thanks for that. It got switched in back emails from 1N400x to
IN400x. I am sure I will find it now. Thanks, Steve.
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Eric
M. Jones
Subject: AeroElectric-List:
I hope Bob doesn't mind my butting in.
Steve: Remarkably, the ST BZW06-31 won't do.
Farnell in the UK (Newark in the US) has billions and billions of 1N4005. If
they are sold out use a 1N4004, or 5, or 6, or 7. Easy to get. By the Way
that's ONE-N4004!
________________________________________________________________________________
| From: | Larry <larry(at)grrok.com> |
| Subject: | Re: Neutral cure silicone |
??Will these urethane adhesives hold paint??
At 05:34 PM 10/16/03, you wrote:
>
>It performs just as well as it's acetic acid curing counterpart. When you
>ask if it is "as strong" as the other form do remember that none of the
>silicones should be viewed as a structural adhesives. If you need a
>waterproof adhesive/sealer which has significant strength you need to be
>considering urethane adhesives. These are used to install auto
>windshields and in this application must retain the windshield in the
>event of an airbag deploying. This can place an almost instantaneous load
>of up to half a ton of outward pressure. I know of one builder who used
>this type of adhesive to attach hi canopy to the frame of a slider and I
>am actually considering the same method for my 9 tipper.
>Fly safe
>Rob
>
>From: richard(at)riley.net
>Subject: Re: AeroElectric-List: Strobe head fix and silicone
>
>
>Is "neutral cure" silicone as strong, weather resistant and temperature
>restistant, etc, as the acetic acid stuff?
>
>
>
> >
> >Subject: Re: AeroElectric-List: Strobe head fix
> >
> > >Can silicone be used to re-seal the glass lens to the transformer/plastic
> > >base of the head ?
> > >If so, what grade is best ?
> >Bob's answer was
> > Electronic grade (does not smell of vinegar).
> >
> >This is also known as "neutral cure" silicone and should be available for
> >less than five bucks a tube from any auto glass shop. This is a far safer
> >product to use around any metal construction as it is non acidic than the
> >normal silicones which contain acetic acid.
> >Clean the surfaces carefully with alcohol and allow to dry before
> >applying. Depending on how thickly you apply it it can take over twenty
> >four hours to fully cure so make sure the parts are held together at least
> >overnight.
> >Good luck
> >Rob
> >Rob W M Shipley
> >RV9A N919RV (res) Fuselage
> >
> >
>
>
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
In preparation for the "CCA FatCables", I am searching for good crimping
dies for AWG 1/0 to AWG 8 or so. Does anyone have a suggestion for good
quality crimpers for these sizes for not too much money?
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
Heaven: A place where the French are the cooks,
the Germans are the engineers,
and the British are the policemen.
Hell: A place where the British are the
cooks, the French are the engineers,
and the Germans are the policemen.
--unknown
________________________________________________________________________________
| From: | "Scott, Ian" <ian_scott(at)rslcom.com.au> |
HI Bob,
Received the copy of the connection, and the Audio ISO board, thanks.
As We do not have the same suppliers in Australia, I am wondering if you have a
generic parts list for the parts in the Audio Amp.
thanks
Ian
----------------------------------------------------
RSL COM has an extensive and competitive range of
local and long distance call packages. We also
offer converged multimedia and data services through
our own state-of-the-art integrated voice & data network.
Visit http://www.rslcom.com.au to find out more.
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
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to such person), you may not copy or deliver this
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this message, and notify us immediately.
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otherwise and the sender is authorised to state them to
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----------------------------------------------------
________________________________________________________________________________
| From: | Jim Sower <canarder(at)frontiernet.net> |
aeroelectric-list(at)matronics.com, reflector(at)tvbf.org
| Subject: | Alternator Terminals ... |
Question for all you EEs out there. I'm putting a new alternator on my
Velocity. This one will be internally regulated (and have the appropriate
"crowbar" OV protection. The unit I am installing has two terminals
arranged in a "T". One is "field" and the other is "Indicator" (idiot
light). I am blessed that the builder didn't have a 20- or 22- ga wire to
string from the "Alt" (split Alt-Master) switch, so he used both conductors
of 2-wire shielded 24 ga for the 12 ft run from the switch to the
regulator. Anyway, I am betting that one will be enough to excite the
regulator and I can use the other for an idiot light.
Thing is, I have to determine which is which and how the "I" lead works (is
it hot or grounded when there is no output). I aim to wire things up with
jumpers and spin the alternator by hand, so to get the charging voltage at
B+ I will need a resistor between B+ and the line back to the battery. That
done, I can connect stuff up and see if, when all ready to go, the "I" lead
is hot or grounded, and if it goes cold or breaks ground connection when I
spin up the unit.
My questions are: Will this work (will I be able to easily twirl the pulley
and get charging voltage if I put the proper resistor in the circuit (so it
doesn't have to generate much current in order to build up charging
voltage)? What would be an appropriate resistance (and size) of the
resistor I am placing in the circuit?
I know I could have all this done at an alternator rebuild shop, but there's
none convenient to me
Hope this will work. Makes sense to me at this point .... Jim S.
________________________________________________________________________________
| Subject: | Romulin disrupter |
Bob
I'm helping a friend wire a Velocity XL RG. The Panel was done at a very well known
avionics shop.
There are twelve relays that switch position lights, strobes, pitot heat, bat master
start , electronic ignition, etc. The switch panel for these items are overhead.
The
logic for these relays was that running "high" currents through wires ( position
lights?)
extending from the fuselage to the overhead switch panel, would create some type
of
electrical interference , Magnetic fields, or the like and possibly disrupt panel
avionics.
Opinion?
Peter
________________________________________________________________________________
| Subject: | Romulin disrupter |
| From: | "Robinson, Chad" <crobinson(at)rfgonline.com> |
> I'm helping a friend wire a Velocity XL RG. The Panel was done at a very well
known
> avionics shop.
>
> There are twelve relays that switch position lights, strobes, pitot heat, bat
master
> start , electronic ignition, etc. The switch panel for these items are overhead.
The
> logic for these relays was that running "high" currents through wires ( position
lights?)
> extending from the fuselage to the overhead switch panel, would create some type
of
> electrical interference , Magnetic fields, or the like and possibly disrupt panel
> avionics.
Unless there is some noise (which is AC) being placed on the wires, DC current
shouldn't create RF interference but it will create a magnetic field. So DC can
mess up a compass but shouldn't emit anything that might screw up, say, a radio
unless you have a lot of noise on your electrical bus to begin with. FWIW,
the switch panel is normally a lot closer to those "sensitive" avionics. Unless
you have a compass close by, you should be fine. Heck, the metal in the switch
bodies will have an effect on a compass if they're close enough, depending
on the type used.
IMHO, if you DO have such a noisy bus that those wires act as antennae, you'd be
better off rigging a shield braid around them or better still, figuring out
and solving the source of your noise instead of having so many extra parts that
could fail (the relays). Bob has a great guide on his site that shows you how
to create a "choke" to isolate the noise, if you can figure out where it's coming
from.
But it's your plane. I like Bob's "fly comfortably" saying here.
Regards,
Chad
________________________________________________________________________________
| Subject: | Re: Battery Contactor vibration problem |
| From: | Vince Ackerman <vack(at)mac.com> |
Hey Bob,
Got the B&C Contactor you generously sent me, and installed it today (
thanks again, you da man). Did my "tap" test and it seems to work
perfectly. I did take someone on the lists advice and mount it
horizontally, but it works great and never disconnected no matter how
much I tapped on the bracket it's mounted to. That gives me a little
piece of mind.
Did you have a chance to look at the one I sent you?
Thanks again
Vince
On Tuesday, October 7, 2003, at 06:45 AM, Robert L. Nuckolls, III wrote:
>
>
>>
>> I installed a battery master switch with contactor (one or the 3
>> terminal ones sold by Aircraft Spruce) on my Rotorway 162f project.
>> For
>> reasons of space I installed it upside down. While testing out the
>> electrical system I noticed that tapping with a small rubber mallet on
>> the bracket that it's mounted to will cause it to interrupt the power
>> momentarily. It doesn't matter if I tap from top or bottom, it seems
>> to disconnect for a split second. I know it's disconnecting because my
>> rotor tach goes through it's initialization test on first power up,
>> and
>> it's doing that every time. Also, other indicator lights flicker, so
>> it's not just the tach, nor loose battery leads, etc.
>>
>> You can understand my hesitation about using this since it's a helo
>> (they aren't the smoothest) with two FADEC's that can't be
>> electrically
>> interrupted. Are there any stronger or more reliable contactors,
>> perhaps even solid state? Any suggestions for how to fix this?
>
>
> What's your battery voltage? It may be so low as to
> severely reduce the holding force of the coil in the
> energized mode . . . but it has to sag really low. Measure
> the voltage across the coil while energized (battery+
> terminal to small terminal).
>
> If the voltage is over 10v, I'd like to get my hands on that
> contactor. If you'll send me you address, I'll have B&C ship
> you one of their battery contactors today and you can send
> me your questionable device. There's something seriously
> wrong with it if you can get interruptions with vibration.
>
> Bob . . .
>
>
> _-
> =======================================================================
> _-
> =======================================================================
> _-
> =======================================================================
> _-
> =======================================================================
> >
>
>
________________________________________________________________________________
| From: | Jerzy Krasinski <krasinski(at)direcway.com> |
| Subject: | Bob, thermistors for low fuel warning WARNING |
Bob Kuc wrote:
Jim,
I bench tested these sensors. You feed them 12 volts. When they are in
fuel the resistance is so high that the LED will not light. When it is out
of fuel the led lights up. It has been a while, I do not remember if I had
a resister in line or not. I do not believe so........
Bob,
This thermistor seems to have large resistance while within fuel and
cold, it heats up and its resistance goes down when out of fuel. If the
circuit does not have any additional elements it seems that it uses a
negative thermal coefficient (NTC) thermistor.
It is a bad idea to connect a NTC thermistor to a hard voltage source
without a serial current limiting resistor . Such a circuit might get
a subject of thermal runaway.
It works like that: No cooling to the thermistor so its temperature
increases, increase of temperature decreases its resistance, so more
current flows through it, more current generates more heat, so its
temperature increases further and faster, until something melts. Once
it started to go it takes few seconds.
A resistor in series would limit the maximum current. You can select it
so the maximum current is safe. That resistor might be a part of the
circuit of the sensor you have tested, or it might not be there. I
would suggest to check it.
Presence of LED in the loop will not stop the instability cycle because
voltage on a LED does not change much with current. However a
traditional bulb would work fine as a current limiter.
You might get away without resistor if NTC thermistor is large with a
lot of cooling, its resistance around room temperature is large and
applied voltage low, so initial power lost in the thermistor is small.
Unfortunately, it is not exactly as you plan to use it - you want large
temperature change between condition with and without cooling and that
implies significant power lost in the thermistor.
As I said, sometimes you might get away without current limiting
resistor, but you run a potentially unstable circuit that is just
waiting for an occasion to blow, which might happen on a warmer day, or
when you look the other way.
Jerzy
________________________________________________________________________________
| Subject: | Bob, thermistors for low fuel warning WARNING |
| From: | "Scott, Ian" <ian_scott(at)rslcom.com.au> |
"ax"
is this wise to run a device that deliberately heats up inside your fuel tank?
what are the explosive risks if it where to fail?
Ian
----------------------------------------------------
RSL COM has an extensive and competitive range of
local and long distance call packages. We also
offer converged multimedia and data services through
our own state-of-the-art integrated voice & data network.
Visit http://www.rslcom.com.au to find out more.
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: | "Trampas" <tstern(at)nc.rr.com> |
| Subject: | Bob, thermistors for low fuel warning WARNING |
I have worked on many cars and seen fuel pumps with black marks on the fuel
pump from electrical arcing, and yes these were in tank fuel pumps. The
reason that the tanks do not explode is that you have to have oxygen, fuel,
and heat for a fire.
Actually a friend of mine was a fireman, he said that car gas tanks were
more dangerous when empty than when full because when empty you had more
oxygen in the tank. He said this increased the likely hood of the tank
exploding, of course he also said in all the car fires he had been to never
once did he see an explosion.
The heat generated by the thermistors would be much lower than heat
generated by a fuel pump in normal operation. Also if you think about it,
the resistive float senders have current running through them and thus they
also will heat up as well.
To look at it another way, there are millions of cars on the road with these
types of low fuel warnings, I know I personally have never heard of one of
them exploding.
However as Bob says, you need to "fly comfortable" if you feel this is a
risk then it is your plane and you have to don't have to put one in.
Trampas
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Scott,
Ian
Subject: RE: AeroElectric-List: Bob, thermistors for low fuel warning
WARNING
is this wise to run a device that deliberately heats up inside your fuel
tank? what are the explosive risks if it where to fail?
Ian
----------------------------------------------------
RSL COM has an extensive and competitive range of
local and long distance call packages. We also
offer converged multimedia and data services through
our own state-of-the-art integrated voice & data network.
Visit http://www.rslcom.com.au to find out more.
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.
----------------------------------------------------
________________________________________________________________________________
| Subject: | Re:AOL Blocking All Email From Matronics.Com |
Matt:
The direct no. for the AOL postmaster is : 1-888-212-5537
Steve
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> WARNING |
| Subject: | Bob, thermistors for low fuel warning |
WARNING
WARNING
>
>I have worked on many cars and seen fuel pumps with black marks on the fuel
>pump from electrical arcing, and yes these were in tank fuel pumps. The
>reason that the tanks do not explode is that you have to have oxygen, fuel,
>and heat for a fire.
>
>Actually a friend of mine was a fireman, he said that car gas tanks were
>more dangerous when empty than when full because when empty you had more
>oxygen in the tank. He said this increased the likely hood of the tank
>exploding, of course he also said in all the car fires he had been to never
>once did he see an explosion.
This simple law of physics has killed more than one welder . . .
>The heat generated by the thermistors would be much lower than heat
>generated by a fuel pump in normal operation. Also if you think about it,
>the resistive float senders have current running through them and thus they
>also will heat up as well.
It isn't so much a matter of total energy or heat as it is concentration
of energy. The energy in watt-seconds delivered by a spark plug is
measured in thousands of a watt-second . . . or millijoules. Your
strobes give you a nice bright light with 20 JOULES of energy per flash,
your sparkplug has to light the fire with 1,000th that level of energy.
It does it by concentrating release of energy in a very small space
that under ideal conditions is shared with a stoichiometric combination
of fuel and oxidizer.
>To look at it another way, there are millions of cars on the road with these
>types of low fuel warnings, I know I personally have never heard of one of
>them exploding.
>
>However as Bob says, you need to "fly comfortable" if you feel this is a
>risk then it is your plane and you have to don't have to put one in.
This is correct. There are several ways to make an electrical system
peacefully co-exist with a potentially explosive environment. One is
to seal the ignition source so completely that explosive constituents
can't get to it (use around oil refineries). Another is to enclose
the ignition source in a container stout enough to withstand an
internal explosion and/or vent the enclosure to the outside through
flame arresting vents (very common in motors). Yet another way is
to design for intrinsically safe energy levels carried by potential
ignition sources within the hazardous atmosphere. The last philosophy
says that no matter how the electrical device fails, it cannot deliver
sufficient energy even to a stoichiometric mixture to get
ignition. This technique has been used successfully for hundreds of
millions of automobiles and other gasoline driven machines for nearly
100 years.
Another aspect of explosion science is that for the explosion to
occur with maximum release of energy, you need to achieve stoichiometric
or ideal proportions of fuel and oxidizer . . . like setting your
mixture control for max rpm on the engine. Effectiveness of combustion
falls off rapidly on either side of the ideal ratio.
A tank with ANY amount of liquid fuel at the bottom will have an
atmosphere above the fuel that is SATURATED . . . i.e. contains
as many dissolved molecules of fuel as the space can contain at
the present temperature and pressure. This ratio of fuel to
oxidizer is a long way from stoichiometric. Every aviation
fuel tank SHOULD have unusable fuel . . . a low space were water
and fuel will collect in a manner that is inaccessible to the
engine but accessible to a sump drain.
This is one of the simple-ideas that argues against the popularly
circulated story about TWA800 . . . Jet A is specifically designed
for it's airplane friendly characteristics. Just as fuel gages have
been used in cars for a century, a half century experience with
millions of flights have produced no examples of violation of
a this simple law of physics.
Now, if someone wants to talk about a LEAK into an enclose space
nearby but outside a tank . . . that is a whole new ball game. But
people who understand and use simple-ideas do not concern themselves
with fuel tank explosions. Now, if your airplane's fuel system is
capable of delivering every ounce of fuel to the engine, you might
want to rethink the design for a number of very good reasons.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Romulin disrupter |
>
>Bob
>
>I'm helping a friend wire a Velocity XL RG. The Panel was done at a very
>well known
>avionics shop.
>
>There are twelve relays that switch position lights, strobes, pitot heat,
>bat master
>start , electronic ignition, etc. The switch panel for these items are
>overhead. The
>logic for these relays was that running "high" currents through wires (
>position lights?)
>extending from the fuselage to the overhead switch panel, would create
>some type of
>electrical interference , Magnetic fields, or the like and possibly
>disrupt panel
>avionics.
>Opinion?
You're the second builder in the past week to note the
acres-of-relays technique to achieve some ill-conceived benefit
in designing an aircraft electrical system.
See http://www.aeroelectric.com/Pictures/TooManyRelays.jpg
There is no foundation in physics or even demonstrated practice
for taking this blanket approach to potential interference
control. Further, it illustrates a serious lack of understanding
on the part of the designer. Worse yet, it increases weight,
complexity, cost of ownership and reduces reliability.
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>
>HI Bob,
>
>Received the copy of the connection, and the Audio ISO board, thanks.
>
>As We do not have the same suppliers in Australia, I am wondering if you
>have a generic parts list for the parts in the Audio Amp.
>
>thanks
The description column is the generic data for
parts substitution. Any electronics supplier should
be able to provide ELECTRICALLY equivalent parts. There
is a small risk that some substituted parts wont fit the
holes in the board but this is a small risk.
Digikey will ship to Australia. I suspect duties
on a handfull of detail electronics parts is minimal
of not zero. Unless you have a local over-the-counter
electronics parts supplier that will help you stuff
all the holes with suitable parts, and internet order
to Digikey is still your best bet.
See http://www.digikey.com
Bob . . .
________________________________________________________________________________
| From: | BobsV35B(at)aol.com |
| Subject: | Re:AOL Blocking All Email From Matronics.Com |
Hi Howard,
This was on the Matronics list
The direct no. for the AOL postmaster is : 1-888-212-5537
Happy Skies,
Old Bob
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Battery Contactor vibration problem |
>
>Hey Bob,
>
>Got the B&C Contactor you generously sent me, and installed it today (
>thanks again, you da man). Did my "tap" test and it seems to work
>perfectly. I did take someone on the lists advice and mount it
>horizontally, but it works great and never disconnected no matter how
>much I tapped on the bracket it's mounted to. That gives me a little
>piece of mind.
>
>Did you have a chance to look at the one I sent you?
It was waiting for me in the mailbox when I got home
last night. I got the harness drawing for a Rotorway Exec 162
also.
I am mystified as to the rational for some of the architecture
decisions in this system. The most striking feature is the
fact that dual FADECs share common wiring, particularly connectors.
The system also has a lot of always hot wiring (no battery contactor)
which could not get approved on a certified airplane. It appears
that many of the decisions driving architecture had more to do
with the fabrication of harnesses for installation convenience and
little or no attention to failure mode effects analysis.
When you have dual systems intended to back each other up
in case of damage and/or component failure, you try to isolate
the two systems to the maximum extend possible including
separate/independent power sources.
I would not be comfortable owning this airplane with the
notion of using it to spend many hours aloft.
I'll try to investigate the battery contactor later today.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Alternator Terminals ... |
>
> Question for all you EEs out there. I'm putting a new alternator on my
>Velocity. This one will be internally regulated (and have the appropriate
>"crowbar" OV protection. The unit I am installing has two terminals
>arranged in a "T". One is "field" and the other is "Indicator" (idiot
>light). I am blessed that the builder didn't have a 20- or 22- ga wire to
>string from the "Alt" (split Alt-Master) switch, so he used both conductors
>of 2-wire shielded 24 ga for the 12 ft run from the switch to the
>regulator. Anyway, I am betting that one will be enough to excite the
>regulator and I can use the other for an idiot light.
Ignore the built in idiot light. There are failure modes that
this light will not annunicate. A separate, active notification
of low voltage like that offered in B&C Altenrator System Controllers
or at:
http://www.aeroelectric.com/Catalog/AEC/9005/9005.html
or
http://www.aeroelectric.com/articles/lvwarn/LVWarn-ABMM.html
and
http://www.aeroelectric.com/articles/lvwarn/9021-620.pdf
>Thing is, I have to determine which is which and how the "I" lead works (is
>it hot or grounded when there is no output). I aim to wire things up with
>jumpers and spin the alternator by hand, so to get the charging voltage at
>B+ I will need a resistor between B+ and the line back to the battery.
Not sure what you're suggesting here. If you want to test the alternator,
hook B+ to a battery through a reasonably robust fuse . . . sized for
alternator output if you're going to spin in hard enough to get full
output.
> That
>done, I can connect stuff up and see if, when all ready to go, the "I" lead
>is hot or grounded, and if it goes cold or breaks ground connection when I
>spin up the unit.
It's a pull down to ground. Hook a light bulb from bus to the "I" terminal.
>My questions are: Will this work (will I be able to easily twirl the pulley
>and get charging voltage if I put the proper resistor in the circuit (so it
>doesn't have to generate much current in order to build up charging
>voltage)? What would be an appropriate resistance (and size) of the
>resistor I am placing in the circuit?
If this is a new alternator, then it's a reasonable assumption that
it works. I'd ignore the "I" lead - UNLESS it's an OLD alternator
design that needs start-up excitation fed to this pin. In this case,
a 30-50 ohm, 2-watt resistor connected from B+ to "I" will do the
job.
Bob .. .
________________________________________________________________________________
| From: | Geoff Evans <hellothaimassage(at)yahoo.com> |
Can anyone compare and contrast the panel lighting dimmer listed in Vans
catalog with the dimmer offered by B&C?
Both appear to good for 1.5A, but the Vans dimmer is less than half the cost
of the B&C dimmer. I know you get what you pay for, but I'd like to know what
the differences are. There is no picture in the Vans catalog, so I'm not
really too sure what they're offering.
Thanks.
-Geoff
RV-8 QB
__________________________________
________________________________________________________________________________
| From: | PTACKABURY(at)aol.com |
| Subject: | Current Limiters |
Bob: I am resending this question as I never heard from you and maybe I was
a casuality of your server's battle with AOL. In any case, here goes:
Bob: Help!! I am building a Lancair IV and am at the wire stringing stage.
I have two 17 amp hour batteries and one 70 amp alternator. I have adopted a
version of your Z-13 for the power distribution architecture, but can't
figure out how many, where and what size current limiters I should use. Part of
the problem is I can't read the diagrams in your book as the small print is
fuzzy (and my eyes are on their sixth decade). Another problem is I don't know
how to size the current limiters: eg: one 40 amp at each battery and one 60
amp at the alternator, or are they sized based on wire size and length like
fuses and cbs. So please tell me how to configure my current limiters. thanks
and regards, paul
________________________________________________________________________________
| From: | "Ron Raby" <ronr(at)advanceddesign.com> |
| Subject: | Re: Crimping dies |
Eric
I use the T&B TBM-8S. Not that cheap.
Ron Raby
----- Original Message -----
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: AeroElectric-List: Crimping dies
>
> In preparation for the "CCA FatCables", I am searching for good crimping
> dies for AWG 1/0 to AWG 8 or so. Does anyone have a suggestion for good
> quality crimpers for these sizes for not too much money?
>
> Regards,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones(at)charter.net
>
> Heaven: A place where the French are the cooks,
> the Germans are the engineers,
> and the British are the policemen.
>
> Hell: A place where the British are the
> cooks, the French are the engineers,
> and the Germans are the policemen.
> --unknown
>
>
________________________________________________________________________________
| From: | Charles Brame <charleyb(at)earthlink.net> |
Bob et.al.,
A couple (or three) dumb questions, thus showing my complete ingnorance
of things electrical.
I am wiring an SD-8 into my All Electric on a Budget RV-6A. Figure Z-13
shows 12AWG wire from the SD-8 to the S704-1 contactor, and from there
to the main battery contactor via a 16AWG fuselink. A 14AWG wire is
shown connecting the main battery contactor to the battery bus with
16AWG continuing on to the Ess bus. Z-13 also shows the SD-8 and
regulator leads to be 12AWG; however, the pigtails provided with my SD-8
are labeled 14AWG and the pigtails on the Regulator appear to be the
same or smaller.
Can I safely substitute 14AWG for the 12AWG? The run will be less than 3
feet and the wire must pass through a VM-1000 Hall Sensor (along with a
6AWG fat wire) thus the need for the smallest practical wire. If I can
use 14AWG wire, what should be the size of the fuselink?
To further muddy the situation, my E-bus is rather heavy with IFR
avionics and electric gyros - I estimate 20+ Amps with everything on.
And in a fit of overkill, my main contactor to Battery Bus is a robust 8AWG.
I sure appreaciate this forum and your outstanding advice.
Charlie Brame
RV-6A N11CB
San Antonio
________________________________________________________________________________
| From: | "Dawson, Bill" <Bill.Dawson(at)pepperdine.edu> |
I use one from http://www.epm-avcorp.com/
It's been great.
Bill
-----Original Message-----
From: Ron Raby [mailto:ronr(at)advanceddesign.com]
Subject: Re: AeroElectric-List: Crimping dies
Eric
I use the T&B TBM-8S. Not that cheap.
Ron Raby
----- Original Message -----
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: AeroElectric-List: Crimping dies
>
> In preparation for the "CCA FatCables", I am searching for good crimping
> dies for AWG 1/0 to AWG 8 or so. Does anyone have a suggestion for good
> quality crimpers for these sizes for not too much money?
>
> Regards,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones(at)charter.net
>
> Heaven: A place where the French are the cooks,
> the Germans are the engineers,
> and the British are the policemen.
>
> Hell: A place where the British are the
> cooks, the French are the engineers,
> and the Germans are the policemen.
> --unknown
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Battery Contactor vibration problem |
>
>Hey Bob,
>
>Got the B&C Contactor you generously sent me, and installed it today (
>thanks again, you da man). Did my "tap" test and it seems to work
>perfectly. I did take someone on the lists advice and mount it
>horizontally, but it works great and never disconnected no matter how
>much I tapped on the bracket it's mounted to. That gives me a little
>piece of mind.
>
>Did you have a chance to look at the one I sent you?
Yes. Went to the workbench and wired up your Cole-Hersee
contactor to a power supply and load resistor. Powered
it up at 10V and 15V. Lightly tapped with a
hammer and took the following response graphs:
http://www.aeroelectric.com/temp/CH10V.jpg
http://www.aeroelectric.com/temp/CH15V.jpg
Dug out a RBM/Stancor part and repeated the experiment:
http://www.aeroelectric.com/temp/RS15V.jpg
http://www.aeroelectric.com/temp/RS10V.jpg
Both brands of contactor are similarly affected
by the hammer taps.
After some reflection, I'm not surprised. While
relatively light taps were used, a rigid metal
mass striking another rigid metal mass can easily
generate acceleration pulses (shock)
of 100-1000G . . . The pulses are very short
meaning that the energy transferred is low . . .
but instantaneous force to components mounted
within can be substantial.
Forgive the non-quantified words above like "light"
"short" "substantial" and "low" . . . I don't have
the tools in my shop to instrument and quantify
these phenomenon. However, I will invoke some hands-
on experience with qualifying flight hardware at
shock levels of 400G or more . . . it's NOT difficult
to impart stimulus of 100 to 1000G in these situations.
You'll note that documented disruptions are on the order
of 1 to 3 milliseconds in length and steep sided.
The steep sides says there was no arc forming in the
contact gaps. You will also note that each event
generated 2 to 5 circuit interruptions (contact bounce).
Playing with the test fixture demonstrated that the
number of interruptions per event had more to do with
tapping-technique and chance than with any observable
difference between the two brands of contactor.
Okay, what's this all mean?
(1) let us note that both contactor designs are
at least 50 years old and no doubt been produced in
millions of parts. If the parts are still in production,
it's a fair assumption that the vast majority of
users have experienced satisfactory service life
WHETHER OR NOT they were aware of the propensity for
bouncing contacts if tapped with a hammer.
(2) the stimulus is not cyclical vibration but short,
high-g shocks . . . a stimulus rarely found in an
airframe or any other vehicle.
(3) Interruptions of 3 millisecond interruptions and
more are EXACTLY the kinds of power input perturbations
that DO-160 tells us to EXPECT and be prepared to
shrug it off.
(4) the act of rotating the mounting axis of a contactor
to ward off evil shocking spirits is not useful
. . . aerodynamic linear g-loads can be reasonably
expected to maximize through the vertical axis . . .
mechanical shock may come from any direction.
Bottom line:
If you hammer-tap any contactor of this genre, you'll
undoubtedly produce the same kind of interruptions
that Vince noted and brought to our attention. I'm
pleased to have an opportunity to compare two
brands of similar devices and to have a reason to sit
down and consider their relative design features.
It's useful to make a new discovery of old data and
understand its significance in the design and operation
of our airplanes.
What I've learned today doesn't change my recommendations
for using these el-cheapo contactors in a well-considered,
failure-tolerant design. I continue to be of the opinion
that they will give good value performance free of extraordinary
risk when mounted in any orientation for ease of installation.
>Thanks again
>
>Vince
Thank you sir! I figure any day you go to bed knowing
something you didn't know yesterday is a good day. This
would not have come to light without your observations
and a willingness to ask the question.
I cranked though a number of plausible but way-out-in-left-
field scenarios to explain what you observed. It was quite
useful to put all those hypotheses in the trash and
discover the truth . . . and best yet . . . to find that
it didn't matter!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Z-13 Question |
>
>
>Bob et.al.,
>
>A couple (or three) dumb questions, thus showing my complete ingnorance
>of things electrical.
>
>I am wiring an SD-8 into my All Electric on a Budget RV-6A. Figure Z-13
>shows 12AWG wire from the SD-8 to the S704-1 contactor, and from there
>to the main battery contactor via a 16AWG fuselink. A 14AWG wire is
>shown connecting the main battery contactor to the battery bus with
>16AWG continuing on to the Ess bus. Z-13 also shows the SD-8 and
>regulator leads to be 12AWG; however, the pigtails provided with my SD-8
>are labeled 14AWG and the pigtails on the Regulator appear to be the
>same or smaller.
Depending on where your battery is located, it may be useful
to make some of the runs 12AWG . . . An RV-8 with battery in
tail would be a good case in point. If your battery is up front,
14AWG with 18AWG fusible link is fine.
>Can I safely substitute 14AWG for the 12AWG? The run will be less than 3
>feet and the wire must pass through a VM-1000 Hall Sensor (along with a
>6AWG fat wire) thus the need for the smallest practical wire. If I can
>use 14AWG wire, what should be the size of the fuselink?
>
>To further muddy the situation, my E-bus is rather heavy with IFR
>avionics and electric gyros - I estimate 20+ Amps with everything on.
>And in a fit of overkill, my main contactor to Battery Bus is a robust 8AWG.
How much of this stuff do you need to run in the en route mode
of flight? This is suppose to be an endurance bus which (when
combined with unlimited engine driven support of 8-10A) saves
100% of battery reserves for the descent to landing phase.
Except for pitot heat, the SD-8 ought to very nicely carry
everything you need to use up fuel aboard and still have
lots of battery snort left to wrap up the flight running
anything NEEDED to get you on the ground. Suggest you revisit
your e-bus load analysis.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Current Limiters |
>
>Bob: I am resending this question as I never heard from you and maybe I was
>a casuality of your server's battle with AOL. In any case, here goes:
>
>Bob: Help!! I am building a Lancair IV and am at the wire stringing stage.
>I have two 17 amp hour batteries and one 70 amp alternator. I have adopted a
>version of your Z-13 for the power distribution architecture, but can't
>figure out how many, where and what size current limiters I should use.
> Part of
>the problem is I can't read the diagrams in your book as the small print is
>fuzzy (and my eyes are on their sixth decade).
I presume you're really looking at Z-14 . . . much more appropriate
to your class of aircraft and the alternators you've cited. If you'd
like to tape two pieces of paper together for a larger version of Z-14,
download
http://www.aeroelectric.com/articles/Appendix_Z_Drawings/z14h_A.pdf
and
http://www.aeroelectric.com/articles/Appendix_Z_Drawings/z14h_B.pdf
and with some minor scissors work and a little tape, you can have
an 11x15" drawing.
> Another problem is I don't know
>how to size the current limiters: eg: one 40 amp at each battery and one 60
>amp at the alternator, or are they sized based on wire size and length like
>fuses and cbs. So please tell me how to configure my current
>limiters. thanks
>and regards, paul
You need only two. An ANL60 (upper right corner of drawing) would be
just fine
for the 70A alternator, an ANL30 (lower left corner of drawing) would be
good
for the 40A alternator.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>Can anyone compare and contrast the panel lighting dimmer listed in Vans
>catalog with the dimmer offered by B&C?
>
>Both appear to good for 1.5A, but the Vans dimmer is less than half the cost
>of the B&C dimmer. I know you get what you pay for, but I'd like to know what
>the differences are. There is no picture in the Vans catalog, so I'm not
>really too sure what they're offering.
I am unfamiliar with Van's offering. Can anyone help Geoff out here?
Bob . . .
________________________________________________________________________________
| Subject: | Re: Bob, external power receptacle |
Bob, I put your ground power circuit (without the indicator) into my
Glasair. One morning, I came into my hangar and found the airplane battery
dead.
The problem was that if you charge your battery, and then unplug the charger
without pulling out the controlling circuit breaker, the charging contactor
stays energized (and therefore drawing current) even with the master battery
switch off. This is an easy mistake to make.
Jim Oberst.
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Bob, external power receptacle
>
> >
> >
> >Bob,
> >I got a receptacle which is used commonly for connection to an external
> >battery if internal battery is week. I was told that the receptacle is
> >from a Cessna. I hoped for an easy installation but there are three
> >prongs there. Two big ones are described "+" (the central one), and
> >"-" (the side one). Unfortunately, there is a third one, smaller. No
> >description there, but there are two ~1A diodes connected to it, able
> >to conduct "from" the prong.
>
> There are two commonly used ground power receptacles in the
> wild. One is a Cole-Hersey product designed for over the road
> trucks and adapted to aircraft by Piper about 40 years ago.
> It's has be popularized as the "Piper style ground power jack."
> This is a simple, cylinder with outside shell as ground, and
> a single robust center pin as power.
>
> In the years BP (before Piper) the military and air transport
> communities developed a three terminal plug/socket combination
> which you have described. It's a military standard part used
> on many ground and air vehicle applications and is the connector
> of choice for most aircraft.
>
>
> >I would like to make the receptacle compatible with battery carts at
> >airports, so Cessna standard seems to be the right one. But how is the
> >third prong connected? Is it used to drive a relay or something?
>
> Consider what happens if you make or break a high current
> connection while energized. There is bound to be arcing that
> ultimately damages the contacts of the connector. The third
> pin is smaller (is sized only for mechanical robustness and
> carries only a few amps in operation) and shorter (connects
> AFTER the big guys are hooked up and disconnects BEFORE
> the big guys do). This pin is used to control a ground power
> contactor in the in a manner that makes sure that
> power cannot flow through the big pins while the connector
> is being mated or de-mated. Originally, this was the ONLY
> purpose for the small pin.
>
> Other features have been added over the years to include
> some components for ov and reverse polarity protection.
> I have illustrated wiring for both the Piper style and
> military style ground power jacks in an article at:
>
> http://www.aeroelectric.com/articles/grndpwr.pdf
>
> If it were my airplane, I'd go the "Piper" route.
> The military style is a pain in the arse to install.
> You need to fabricate your own door or mount it
> someplace where a door is not needed. The Piper
> style comes with its own door built in, is much
> easier to install, and probably lighter than
> the 3-pin connector installation.
>
> Another advantage of the Cole-Hersey connector
> is that you can have your own ground power jumper
> cables made up and it two is lighter than one
> using the fatter military style connector and
> a LOT less expensive.
>
> Bob . . .
>
>
> >I could not find anything on thet topic. I would appreciate your answer.
> >Thank you,
> >Jerzy
> >
> >Werner Schneider wrote:
> >
> >
> > >
> > >Interesting approach, would wonder what happens if you have a fuel
injected
> > >engine with a return line (of "hot" fuel) back into the tanks.
> > >
> > >I'm using a optical device in my Glastar, works great and as it is LED
it
> > >needs nearly no power!!
> > >
> > >http://www.ppavionics.com/LFL.htm
> > >
> > >Werner
> > >
> > >----- Original Message -----
> > >
> > >
> > >
> > >>When the thermistor is immersed in fuel, the fuel keeps the thermistor
> > >>cooled off, the resistance remains high and the indicator light bulb
does
> > >>not light up.
> > >>
> > >>
> > >
> > >
> > >
> > >
> >
> >
>
> Bob . . .
>
> --------------------------------------------
> ( Knowing about a thing is different than )
> ( understanding it. One can know a lot )
> ( and still understand nothing. )
> ( C.F. Kettering )
> --------------------------------------------
>
>
________________________________________________________________________________
| From: | "Robinson, Chad" <crobinson(at)rfgonline.com> |
In case nobody else responds, you can make some guesses if you squint hard at the
fourth-to-last picture here:
http://www.rvproject.com/20030505.html
Looks like a pot controlling a single, heat-sunk TO-220 package device with only
a few other components on the board. I'm guessing an LM317?
B&C's site has a picture of their dimmer, which doesn't look like much more, but
it's a heck of a big heat sink. Also, it includes some DB-9 connectors that
add to the parts count but makes it easier to hook up, and the mounting tabs look
a lot easier to work with. Bob, do you know where they sourced this heat sink?
Looks like a nice getup.
I see B&C also offers a 5A option, which will control a heck of a lot more lights
- no way will that itty bitty heat sink picture on this Van's builder's site
stand up to even a portion of that without torching the board, unless this picture
isn't of the right thing.
The TO-3 picture in even the smaller of B&C's site can better dissipate heat to
begin with (over the TO-220 package), so I'm certain it will stand up to the
load it says it will. But that setup I see pictured on this Van's builder's site
won't take more than 500mA or so unless there's a fan blowing on it - that
will limit the number of lights it can control. (Read as 1/3 as many lights, if
that. And don't plan on touching it.)
Bear in mind that linear regulators, which these all are, just convert the excess
voltage to heat, so the DIMMER your lights are the HOTTER they get (some people
find this counter-intuitive). That means that if you hardly dim your lights
you may never notice the difference, until you turn them way down one day and
the dimmer torches anything that might be touching it.
> -----Original Message-----
> From: Robert L. Nuckolls, III [mailto:bob.nuckolls(at)cox.net]
> Sent: Monday, October 20, 2003 6:49 PM
> To: aeroelectric-list(at)matronics.com
> Subject: Re: AeroElectric-List: Dimmers
>
>
> III"
>
> >
> >
> >Can anyone compare and contrast the panel lighting dimmer
> listed in Vans
> >catalog with the dimmer offered by B&C?
> >
> >Both appear to good for 1.5A, but the Vans dimmer is less
> than half the cost
> >of the B&C dimmer. I know you get what you pay for, but I'd
> like to know what
> >the differences are. There is no picture in the Vans
> catalog, so I'm not
> >really too sure what they're offering.
>
> I am unfamiliar with Van's offering. Can anyone help Geoff out here?
>
> Bob . . .
>
>
> ============
> ============
________________________________________________________________________________
| From: | Charlie & Tupper England <cengland(at)netdoor.com> |
| Subject: | Re: Crimping dies |
Eric M. Jones wrote:
>
>In preparation for the "CCA FatCables", I am searching for good crimping
>dies for AWG 1/0 to AWG 8 or so. Does anyone have a suggestion for good
>quality crimpers for these sizes for not too much money?
>
>Regards,
>Eric M. Jones
>www.PerihelionDesign.com
>113 Brentwood Drive
>Southbridge MA 01550-2705
>Phone (508) 764-2072
>Email: emjones(at)charter.net
>
The best crimper you can buy for 'not too much money' for big wires is
a propane torch.
Charlie
(Let the 'stress riser games' begin...)
:-)
________________________________________________________________________________
| From: | Jim Daniels <jwdanie(at)comcast.net> |
At the top of this page is a picture of the Vans dimmer boards.
http://home.comcast.net/~jwdanie/Wiring2/wiring2.html
They just use an LM317 with a remote pot and another divider resistor.
The 317 has a minimal heatsink (I'm only drawing ~350ma so not a
problem). Note that the board contains locations for filter capacitors
but they are not populated. I opted to install some parts I had around
rather than hoping the regulator didn't oscillate.
I'm not sure I would count on that heatsink at 1.5A, but if your
application, like mine, is not very demanding then it should be no
problem.
Also, I may go in later and tune the pot so that the bottom 1/3rd of
the travel isn't wasted. As designed with the pot below this point the
lights are off, so only partial rotation will control the entire
intensity range.
Jim Daniels
________________________________________________________________________________
| From: | SportAV8R(at)aol.com |
| Subject: | Encoder / Transponder domino failure? |
Okay, gentlemen: help me puzzle this out...
A few weeks ago my RMI microEncoder became erratic in flight, cycling into test
mode and shutting itself off repeatedly. Finished the flight with no mode C
squawk but a normally-functioning transponder; at least I was seeing the interrogation
light come on at the expected level of activity. Tear-down inspection
of the RMI revealed a rattle in the case, turned out that two screws holding
down a heat sink had shed their nuts and lockwashers and fallen free. The screws
were in the bottom of the can, but the nuts and washers had been dancing
around on the solder-side of the lower circuit board, apparently causing the gremlin-action
in flight.
The screw integrity issue seems to have come from the insulating shoulder washers
compressing/separating into sheared-off fragments and exhausting their pre-load
on the fasteners, which then vibrated loose. It was a simple fix (Loc-Tite)
and the bullet-proof uEncoder came back to life and has acted fine since.
Later on, my buddy says he can't see me on his TCAD, and I start to notice the
interrogation light is not doing anything on the next few local flights. That's
odd; I usually get pinged at this altitude at the home field. A cross-country
trip just outside some major Class C confirms that the Garmin GTX 320 is apparently
deaf or mute, and we have a problem.
Dilemma: garmin will bench test it for me and fix it for $250. Cost is the same
even if the unit checks out okay. I know from the startup light that it has
power. How can I be sure it's not a coincidental feedline/antenna problem without
spending 250 bucks?
All I can speculate is that somehow during all the electrical mayhem in the encoder
while the screws were loose, some voltage got into the XPDR via the data
bus from the encoder and let the smoke out of some component. It seems unlikely
that a stray voltage on those pins would damage the very guts of the transponder
rather than just the mode C part, but I'm just musing in the dark.
Ideas appreciated.
I know of a nearby avionics shop that might be willing I will probably give them
a call tomorrow.
-Bill B
RV-6A
________________________________________________________________________________
| Subject: | Re: Battery Contactor vibration problem |
| From: | Vince Ackerman <vack(at)mac.com> |
I glad (sort of ) that it wasn't just me and you could duplicate what I
did with a little more eloquence. The bottom line for an aircraft
(helicopter ) like mine, with FADEC's that cannot tolerate any power
interuptions, is still a question in my mind. What are the options?
Give a vibration that could disrupt the contactor, what could bridge
the millisecond power interuptions that would keep the computers from
shutting down and rebooting? Some sort of capacitor? A rubber mount for
the contactor? I'm not an electrical engineer by any stretch, so your
suggestions would be most valuable.
Thanks
Vince
On Monday, October 20, 2003, at 02:19 PM, Robert L. Nuckolls, III wrote:
>
>
>
> Yes. Went to the workbench and wired up your Cole-Hersee
> contactor to a power supply and load resistor. Powered
> it up at 10V and 15V. Lightly tapped with a
> hammer and took the following response graphs:
>
> http://www.aeroelectric.com/temp/CH10V.jpg
> http://www.aeroelectric.com/temp/CH15V.jpg
>
>
> Dug out a RBM/Stancor part and repeated the experiment:
>
> http://www.aeroelectric.com/temp/RS15V.jpg
> http://www.aeroelectric.com/temp/RS10V.jpg
>
> Both brands of contactor are similarly affected
> by the hammer taps.
>
> After some reflection, I'm not surprised. While
> relatively light taps were used, a rigid metal
> mass striking another rigid metal mass can easily
> generate acceleration pulses (shock)
> of 100-1000G . . . The pulses are very short
> meaning that the energy transferred is low . . .
> but instantaneous force to components mounted
> within can be substantial.
>
> Forgive the non-quantified words above like "light"
> "short" "substantial" and "low" . . . I don't have
> the tools in my shop to instrument and quantify
> these phenomenon. However, I will invoke some hands-
> on experience with qualifying flight hardware at
> shock levels of 400G or more . . . it's NOT difficult
> to impart stimulus of 100 to 1000G in these situations.
>
> You'll note that documented disruptions are on the order
> of 1 to 3 milliseconds in length and steep sided.
> The steep sides says there was no arc forming in the
> contact gaps. You will also note that each event
> generated 2 to 5 circuit interruptions (contact bounce).
>
> Playing with the test fixture demonstrated that the
> number of interruptions per event had more to do with
> tapping-technique and chance than with any observable
> difference between the two brands of contactor.
>
> Okay, what's this all mean?
>
> (1) let us note that both contactor designs are
> at least 50 years old and no doubt been produced in
> millions of parts. If the parts are still in production,
> it's a fair assumption that the vast majority of
> users have experienced satisfactory service life
> WHETHER OR NOT they were aware of the propensity for
> bouncing contacts if tapped with a hammer.
>
> (2) the stimulus is not cyclical vibration but short,
> high-g shocks . . . a stimulus rarely found in an
> airframe or any other vehicle.
>
> (3) Interruptions of 3 millisecond interruptions and
> more are EXACTLY the kinds of power input perturbations
> that DO-160 tells us to EXPECT and be prepared to
> shrug it off.
>
> (4) the act of rotating the mounting axis of a contactor
> to ward off evil shocking spirits is not useful
> . . . aerodynamic linear g-loads can be reasonably
> expected to maximize through the vertical axis . . .
> mechanical shock may come from any direction.
>
> Bottom line:
>
> If you hammer-tap any contactor of this genre, you'll
> undoubtedly produce the same kind of interruptions
> that Vince noted and brought to our attention. I'm
> pleased to have an opportunity to compare two
> brands of similar devices and to have a reason to sit
> down and consider their relative design features.
> It's useful to make a new discovery of old data and
> understand its significance in the design and operation
> of our airplanes.
>
> What I've learned today doesn't change my recommendations
> for using these el-cheapo contactors in a well-considered,
> failure-tolerant design. I continue to be of the opinion
> that they will give good value performance free of extraordinary
> risk when mounted in any orientation for ease of installation.
>
>
>> Thanks again
>>
>> Vince
>
> Thank you sir! I figure any day you go to bed knowing
> something you didn't know yesterday is a good day. This
> would not have come to light without your observations
> and a willingness to ask the question.
>
> I cranked though a number of plausible but way-out-in-left-
> field scenarios to explain what you observed. It was quite
> useful to put all those hypotheses in the trash and
> discover the truth . . . and best yet . . . to find that
> it didn't matter!
>
> Bob . . .
>
________________________________________________________________________________
| From: | Geoff Evans <hellothaimassage(at)yahoo.com> |
| Subject: | Small aux battery: diode vs. relay |
Bob.
After reading this list for a year or so and perusing the archives, I've
narrowed down my my proposed electrical system from a "that would be nice to
have" design to a "this is all I really need to get the job done" design.
I'm (now) planning dual electronic ignitions, one main battery, and one small
aux battery which ONLY supports the second ignition and is not used for
starting. I might install a SD-8 later, but I don't think I need that for my
VFR ship at this time.
Anyway... You made a comment in one of the archived messages that you prefer
"hard" connections to diodes in this situation. Why is that??
I'm trying to decide between a S704-1 relay with manual control of the small
aux battery bus tie, or a schottky diode to provide current for charging of
the aux battery and operation of the second ignition.
The diode is attractive because it reduces the possibility of pilot error
(like cranking the engine with the aux battery connected) and it reduces the
parts count. However, the relay is attractive because it gives you more
control over the system and doesn't produce the voltage drop that a diode
would. So... Why do you prefer "hard" connections to diodes?
Also... I understand that small aux batteries won't accept a large charging
current, so fat wires are not necessary. You have stated in the past that 18
or 20 AWG wire is fine for charging only a small aux battery and running one
ignition. However, how does one KNOW for sure how much charging current the
small (4.5 AH) battery will accept? The distance between my batteries and
their relays/contactors is less than 6", so I don't plan to protect those
wires. How do I know that I won't smoke the wire going to the aux battery if
(for some strange reason) it is accepting a large charge?
Thanks.
-Geoff
RV-8 QB
__________________________________
________________________________________________________________________________
| From: | "Rob W M Shipley" <rob(at)robsglass.com> |
| Subject: | Neutral cure silicone and urethane adhesive |
Larry,
The automotive urethanes accept auto paints only too well. Body shops are extremely
proficient at painting over a nice cleanly cut layer of urethane left on
the vehicles pinchweld ready for applying the new bead of adhesive and the new
windshield / backglass / quarter window. (Perhaps you can guess I own an autoglass
company. ;-]). They are similar in texture to a stiff rubber and as such
might shed paint if flexed. I would not consider them a good structural foundation
for paint unless used as a thin layer - perhaps 3/32" or less. Smoothing
them is something of an art and if you want more detailed information you
can call me at 619 697 9192 any evening (CA time).
Rob
??Will these urethane adhesives hold paint??
At 05:34 PM 10/16/03, you wrote:
>
>It performs just as well as it's acetic acid curing counterpart. When you
>ask if it is "as strong" as the other form do remember that none of the
>silicones should be viewed as a structural adhesives. If you need a
>waterproof adhesive/sealer which has significant strength you need to be
>considering urethane adhesives. These are used to install auto
>windshields and in this application must retain the windshield in the
>event of an airbag deploying. This can place an almost instantaneous load
>of up to half a ton of outward pressure. I know of one builder who used
>this type of adhesive to attach hi canopy to the frame of a slider and I
>am actually considering the same method for my 9 tipper.
>Fly safe
>Rob
________________________________________________________________________________
| Subject: | Source for BNC adapters? |
Bob or anyone: Does anyone know of a source for the type of BNC adapter
that Garmin uses in their new transponders and nav/com units (other than
direct from Garmin that is). These are the type that install in the chassis with
a
snap ring and have a plug in socket on the inside to mate with the unit and a
BNC jack on the outside.
I want to replace the solder type antenna coax snap ring adapters that came
with my KX-125. I called John Stark, but he said he has been looking for them
also with no success so far.
Harry Crosby
Pleasanton, California
RV-6, firewall forward
________________________________________________________________________________
| From: | <mjheinen(at)adelphia.net> |
Is there a solid state dimmer available yet that only uses the power needed to
light the bulbs without spilling over excess as heat?
>
> From: Jim Daniels <jwdanie(at)comcast.net>
> Date: 2003/10/20 Mon PM 09:58:16 EDT
> To: aeroelectric-list(at)matronics.com
> Subject: Re: AeroElectric-List: Dimmers
>
>
________________________________________________________________________________
| From: | "Neville Kilford" <nkilford(at)etravel.org> |
| Subject: | Re: Encoder / Transponder domino failure? |
Bill,
Have you run the transponder without the encoder? I.e. is it really the
transponder that's at fault, or just some "interference" sort of problem
that's caused by the encoder?
Nev
--
Jodel D150 in progress
UK
----- Original Message -----
From: <SportAV8R(at)aol.com>
Subject: AeroElectric-List: Encoder / Transponder domino failure?
>
> Okay, gentlemen: help me puzzle this out...
>
> A few weeks ago my RMI microEncoder became erratic in flight, cycling into
test mode and shutting itself off repeatedly. Finished the flight with no
mode C squawk but a normally-functioning transponder; at least I was seeing
the interrogation light come on at the expected level of activity. Tear-down
inspection of the RMI revealed a rattle in the case, turned out that two
screws holding down a heat sink had shed their nuts and lockwashers and
fallen free. The screws were in the bottom of the can, but the nuts and
washers had been dancing around on the solder-side of the lower circuit
board, apparently causing the gremlin-action in flight.
>
> The screw integrity issue seems to have come from the insulating shoulder
washers compressing/separating into sheared-off fragments and exhausting
their pre-load on the fasteners, which then vibrated loose. It was a simple
fix (Loc-Tite) and the bullet-proof uEncoder came back to life and has acted
fine since.
>
> Later on, my buddy says he can't see me on his TCAD, and I start to notice
the interrogation light is not doing anything on the next few local flights.
That's odd; I usually get pinged at this altitude at the home field. A
cross-country trip just outside some major Class C confirms that the Garmin
GTX 320 is apparently deaf or mute, and we have a problem.
>
> Dilemma: garmin will bench test it for me and fix it for $250. Cost is
the same even if the unit checks out okay. I know from the startup light
that it has power. How can I be sure it's not a coincidental
feedline/antenna problem without spending 250 bucks?
>
> All I can speculate is that somehow during all the electrical mayhem in the
encoder while the screws were loose, some voltage got into the XPDR via the
data bus from the encoder and let the smoke out of some component. It seems
unlikely that a stray voltage on those pins would damage the very guts of the
transponder rather than just the mode C part, but I'm just musing in the
dark.
>
> Ideas appreciated.
>
> I know of a nearby avionics shop that might be willing I will probably
give them a call tomorrow.
>
> -Bill B
> RV-6A
>
>
________________________________________________________________________________
| From: | "William Slaughter" <willslau(at)alumni.rice.edu> |
| Subject: | Re: Battery Contactor vibration problem |
I'm powering my Aerosance FADEC system directly from the battery busses
via fusible links - no contactor involved.
William Slaughter
RV-8 IOF-360
-----Original Message-----
From: owner-aeroelectric-list-server(at)matronics.com
[mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Vince
Ackerman
Subject: Re: AeroElectric-List: Re: Battery Contactor vibration problem
I glad (sort of ) that it wasn't just me and you could duplicate what I
did with a little more eloquence. The bottom line for an aircraft
(helicopter ) like mine, with FADEC's that cannot tolerate any power
interuptions, is still a question in my mind. What are the options?
Give a vibration that could disrupt the contactor, what could bridge
the millisecond power interuptions that would keep the computers from
shutting down and rebooting? Some sort of capacitor? A rubber mount for
the contactor? I'm not an electrical engineer by any stretch, so your
suggestions would be most valuable.
Thanks
Vince
On Monday, October 20, 2003, at 02:19 PM, Robert L. Nuckolls, III wrote:
>
>
>
> Yes. Went to the workbench and wired up your Cole-Hersee
> contactor to a power supply and load resistor. Powered
> it up at 10V and 15V. Lightly tapped with a
> hammer and took the following response graphs:
>
> http://www.aeroelectric.com/temp/CH10V.jpg
> http://www.aeroelectric.com/temp/CH15V.jpg
>
>
> Dug out a RBM/Stancor part and repeated the experiment:
>
> http://www.aeroelectric.com/temp/RS15V.jpg
> http://www.aeroelectric.com/temp/RS10V.jpg
>
> Both brands of contactor are similarly affected
> by the hammer taps.
>
> After some reflection, I'm not surprised. While
> relatively light taps were used, a rigid metal
> mass striking another rigid metal mass can easily
> generate acceleration pulses (shock)
> of 100-1000G . . . The pulses are very short
> meaning that the energy transferred is low . . .
> but instantaneous force to components mounted
> within can be substantial.
>
> Forgive the non-quantified words above like "light"
> "short" "substantial" and "low" . . . I don't have
> the tools in my shop to instrument and quantify
> these phenomenon. However, I will invoke some hands-
> on experience with qualifying flight hardware at
> shock levels of 400G or more . . . it's NOT difficult
> to impart stimulus of 100 to 1000G in these situations.
>
> You'll note that documented disruptions are on the order
> of 1 to 3 milliseconds in length and steep sided.
> The steep sides says there was no arc forming in the
> contact gaps. You will also note that each event
> generated 2 to 5 circuit interruptions (contact bounce).
>
> Playing with the test fixture demonstrated that the
> number of interruptions per event had more to do with
> tapping-technique and chance than with any observable
> difference between the two brands of contactor.
>
> Okay, what's this all mean?
>
> (1) let us note that both contactor designs are
> at least 50 years old and no doubt been produced in
> millions of parts. If the parts are still in production,
> it's a fair assumption that the vast majority of
> users have experienced satisfactory service life
> WHETHER OR NOT they were aware of the propensity for
> bouncing contacts if tapped with a hammer.
>
> (2) the stimulus is not cyclical vibration but short,
> high-g shocks . . . a stimulus rarely found in an
> airframe or any other vehicle.
>
> (3) Interruptions of 3 millisecond interruptions and
> more are EXACTLY the kinds of power input perturbations
> that DO-160 tells us to EXPECT and be prepared to
> shrug it off.
>
> (4) the act of rotating the mounting axis of a contactor
> to ward off evil shocking spirits is not useful
> . . . aerodynamic linear g-loads can be reasonably
> expected to maximize through the vertical axis . . .
> mechanical shock may come from any direction.
>
> Bottom line:
>
> If you hammer-tap any contactor of this genre, you'll
> undoubtedly produce the same kind of interruptions
> that Vince noted and brought to our attention. I'm
> pleased to have an opportunity to compare two
> brands of similar devices and to have a reason to sit
> down and consider their relative design features.
> It's useful to make a new discovery of old data and
> understand its significance in the design and operation
> of our airplanes.
>
> What I've learned today doesn't change my recommendations
> for using these el-cheapo contactors in a well-considered,
> failure-tolerant design. I continue to be of the opinion
> that they will give good value performance free of extraordinary
> risk when mounted in any orientation for ease of installation.
>
>
>> Thanks again
>>
>> Vince
>
> Thank you sir! I figure any day you go to bed knowing
> something you didn't know yesterday is a good day. This
> would not have come to light without your observations
> and a willingness to ask the question.
>
> I cranked though a number of plausible but way-out-in-left-
> field scenarios to explain what you observed. It was quite
> useful to put all those hypotheses in the trash and
> discover the truth . . . and best yet . . . to find that
> it didn't matter!
>
> Bob . . .
>
==
direct advertising on the Matronics Forums.
==
==
==
________________________________________________________________________________
| From: | SportAV8R(at)aol.com |
| Subject: | Re: Encoder / Transponder domino failure? |
In a message dated 10/21/2003 5:03:33 AM Eastern Daylight Time, nkilford(at)etravel.org
writes:
> Bill,
>
> Have you run the transponder without the encoder? I.e. is it really the
> transponder that's at fault, or just some "interference"
> sort of problem
> that's caused by the encoder?
>
> Nev
No, but that would be easy to accomplish. I will put it on my list of things to
try.
________________________________________________________________________________
| From: | Jim Sower <canarder(at)frontiernet.net> |
I was thinking about using largish LEDs mounted under the glare shield to
shine on my panel. Someone told me that there are dimmers that are actually
oscillators that vary the width of the "ON" pulse to "dim" LEDs. Is there
anything to this? Are these devices readily available? Are they compact
enough to compete with pots for compactness?
Inquiring minds need to know .... Jim S.
________________________________________________________________________________
| From: | "Robinson, Chad" <crobinson(at)rfgonline.com> |
> Is there a solid state dimmer available yet that only uses
> the power needed to light the bulbs without spilling over
> excess as heat?
I don't know of any for the aircraft industry, but they're not hard to build on
a piece of perfboard. They're called "switching" or "switch mode" power supplies.
They're also much more efficient - linear regulators dissipate any excess
power as heat, so you use the same amount of power (plus a small margin) as you
would have used at full brightness. Switching regulators only have that little
margin, so at maximum dim you're using very little power.
For instance, Maxim's MAX8545 is $0.92 in bulk (probably a little over a buck in
single-unit quantities), and have a 2.7V-28V input range. The first page of
their spec sheet has a sample application circuit that you could probably put
on a perfboard in an afternoon's work, if you know how to read a schematic. It's
got about 10 parts, which is more than the linear regulator, but if you were
building it yourself you'd probably still end up saving money.
They are NOT a panacea, however. Switch-mode regulators work by running an oscillator,
which can put out noise that causes all sorts of trouble with other devices.
You can eliminate much of this noise by putting the circuit in a shielded
enclosure, if you're careful. The problem is that "switching artifacts" (more
noise) can still appear on the output, so all those wires to your lights can
act like antennae and radiate that noise. It's possible to eliminate even this
with a good choke design, but that's not exactly a beginner design - you would
need to tune it for the 300kHz switching frequency and possibly a few harmonics.
All things considered, I'd stick with a linear design like B&C's unless you have
a good reason to switch. Heat is an easier problem to deal with than noise.
Regards,
Chad
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Battery Contactor vibration problem |
>
>I glad (sort of ) that it wasn't just me and you could duplicate what I
>did with a little more eloquence. The bottom line for an aircraft
>(helicopter ) like mine, with FADEC's that cannot tolerate any power
>interuptions, is still a question in my mind. What are the options?
>Give a vibration that could disrupt the contactor,
There's a big difference between vibration and shock in terms
of intensity and total energy of the stimulus. You're not
going to see this interruption happen in normal operation
even in a helicopter . . . now, if you hit the side of a
mountain . . .
> what could bridge
>the millisecond power interuptions that would keep the computers from
>shutting down and rebooting? Some sort of capacitor? A rubber mount for
>the contactor? I'm not an electrical engineer by any stretch, so your
>suggestions would be most valuable.
ANY accessory needed for engine operation should run
from a battery bus . . . and ESPECIALLY when the accessory is
known to be ill-prepared to live in the real world of
aircraft. If Rotorway has told you their FADEC is so
afflicted, then this reinforces my not so humble opinion
of their power distribution architecture.
Bob . . .
________________________________________________________________________________
| From: | "John Slade" <sladerj(at)bellsouth.net> |
Jim,
I have the solid state unit from B&C. The one that comes with the goose neck
light. It's small and dims 4 or 5 outputs. Works well with LEDS, not
expensive, and much easier than making one.
John Slade
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Small aux battery: diode vs. relay |
>
>
>Bob.
>
>After reading this list for a year or so and perusing the archives, I've
>narrowed down my my proposed electrical system from a "that would be nice to
>have" design to a "this is all I really need to get the job done" design.
>
>I'm (now) planning dual electronic ignitions, one main battery, and one small
>aux battery which ONLY supports the second ignition and is not used for
>starting. I might install a SD-8 later, but I don't think I need that for my
>VFR ship at this time.
>
>Anyway... You made a comment in one of the archived messages that you prefer
>"hard" connections to diodes in this situation. Why is that??
>
>I'm trying to decide between a S704-1 relay with manual control of the small
>aux battery bus tie, or a schottky diode to provide current for charging of
>the aux battery and operation of the second ignition.
>
>The diode is attractive because it reduces the possibility of pilot error
>(like cranking the engine with the aux battery connected) and it reduces the
>parts count. However, the relay is attractive because it gives you more
>control over the system and doesn't produce the voltage drop that a diode
>would. So... Why do you prefer "hard" connections to diodes?
because you can charge and load the battery thought the same path
and both batteries are always charged at the same bus voltage . .
>Also... I understand that small aux batteries won't accept a large charging
>current, so fat wires are not necessary. You have stated in the past that 18
>or 20 AWG wire is fine for charging only a small aux battery and running one
>ignition. However, how does one KNOW for sure how much charging current the
>small (4.5 AH) battery will accept? The distance between my batteries and
>their relays/contactors is less than 6", so I don't plan to protect those
>wires. How do I know that I won't smoke the wire going to the aux battery if
>(for some strange reason) it is accepting a large charge?
You won't smoke any wires with a battery that small. The only
time the battery would request a high charge rate is if you
ran it down. If it's tied to the main battery with a diode, you
can't run it down unless the main battery is going down too and
or has disappeared. Which begs the question, if you choose not
to provide for complete isolation of the two batteries via hard
contacts, then what scenario do you anticipate that the small
battery would become your last ditch option for plugging the
hole in dike?
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>In case nobody else responds, you can make some guesses if you squint hard
>at the fourth-to-last picture here:
> http://www.rvproject.com/20030505.html
>
>Looks like a pot controlling a single, heat-sunk TO-220 package device
>with only a few other components on the board. I'm guessing an LM317?
>
>B&C's site has a picture of their dimmer, which doesn't look like much
>more, but it's a heck of a big heat sink. Also, it includes some DB-9
>connectors that add to the parts count but makes it easier to hook up, and
>the mounting tabs look a lot easier to work with. Bob, do you know where
>they sourced this heat sink? Looks like a nice getup.
That's the series of dimmers I designed and use to sell off
my website. There are a series of dimmers rated at .5A, 1.5A
3A and 5A. All are electrically identical except for the size
of the heatsink and the linear regulators (lm317, lm350, lm338).
If Van's dimmer doesn't have a heatsink and it features a
linear regulator of the LM317 variety, then it's NOT a 1.5A
capable device. The LM317 will control this load only when
mounted on a suitable heatsink.
The heatsinks I used can be found in the Wakefield Engineering
catalog at:
http://www.wakefield.com/pdf/extruded_heat_sink.pdf
The smaller heatsink is a 401K, the larger is a 403K
>I see B&C also offers a 5A option, which will control a heck of a lot more
>lights - no way will that itty bitty heat sink picture on this Van's
>builder's site stand up to even a portion of that without torching the
>board, unless this picture isn't of the right thing.
The 5A controller has been used mostly for heater motor
controls in airplanes with hot-water heaters.
>The TO-3 picture in even the smaller of B&C's site can better dissipate
>heat to begin with (over the TO-220 package), so I'm certain it will stand
>up to the load it says it will. But that setup I see pictured on this
>Van's builder's site won't take more than 500mA or so unless there's a fan
>blowing on it - that will limit the number of lights it can control. (Read
>as 1/3 as many lights, if that. And don't plan on touching it.)
I believe you are correct . . .
>Bear in mind that linear regulators, which these all are, just convert the
>excess voltage to heat, so the DIMMER your lights are the HOTTER they get
>(some people find this counter-intuitive). That means that if you hardly
>dim your lights you may never notice the difference, until you turn them
>way down one day and the dimmer torches anything that might be touching it.
For the most part, the LM317 will self protect by shutting down
if they get too hot . . . so if you overload Van's dimmer, it might
survive the ordeal. But it's not a 1.5A rated device.
> > -----Original Message-----
> > From: Robert L. Nuckolls, III [mailto:bob.nuckolls(at)cox.net]
> > Sent: Monday, October 20, 2003 6:49 PM
> > To: aeroelectric-list(at)matronics.com
> > Subject: Re: AeroElectric-List: Dimmers
> >
> >
> > III"
> >
> > >
> > >
> > >Can anyone compare and contrast the panel lighting dimmer
> > listed in Vans
> > >catalog with the dimmer offered by B&C?
> > >
> > >Both appear to good for 1.5A, but the Vans dimmer is less
> > than half the cost
> > >of the B&C dimmer. I know you get what you pay for, but I'd
> > like to know what
> > >the differences are. There is no picture in the Vans
> > catalog, so I'm not
> > >really too sure what they're offering.
> >
> > I am unfamiliar with Van's offering. Can anyone help Geoff out here?
> >
> > Bob . . .
> >
> >
> > ============
> > ============
>
>
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Is there a solid state dimmer available yet that only uses the power
>needed to light the bulbs without spilling over excess as heat?
Sure, a number of articles have been published (most notably by
Jim Wier in Kitplanes) on variable duty-cycle controllers
for panel lights. Another way to mitigate heat issues is
to reduce power needed . . . e.g. all LED illumination.
Bob . . .
________________________________________________________________________________
| From: | Klaus Dietrich <Klaus.Dietrich(at)oracle.com> |
| Subject: | LOM-magneto filters |
I'm making the electrics on a LOM powered Bucker and I wonder what sort
of magneto filters (if any) I should use. Can't get hold of the LOM
filters as specified on Bob's drawing for the LOM.
I bought 2 USmade Magneto Filters from Lonestar (Spruce), just to find
out that there is no reasonable way to mount them on the LOM magnetos.
Best I could imagine is to mount them on the firewall, which is 60 cm
away from the mags; don't know if this makes any sense
I changed the LOM generator and use the TK10 Alternator plus OV from B&C
instead.
Thanks for any advise on this one
Klaus, Vienna
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: LOM-magneto filters |
>
>
>I'm making the electrics on a LOM powered Bucker and I wonder what sort
>of magneto filters (if any) I should use. Can't get hold of the LOM
>filters as specified on Bob's drawing for the LOM.
>I bought 2 USmade Magneto Filters from Lonestar (Spruce), just to find
>out that there is no reasonable way to mount them on the LOM magnetos.
>Best I could imagine is to mount them on the firewall, which is 60 cm
>away from the mags; don't know if this makes any sense
>
>I changed the LOM generator and use the TK10 Alternator plus OV from B&C
>instead.
>
>Thanks for any advise on this one
>Klaus, Vienna
First, leave them off entirely and see if they're really
necessary. If you wire the p-leads according to the power
distribution diagram, it's likely that the filters will
not be needed. I included them only because they're called
out on LOM's drawings. I'm not sure they even knew how the
filters worked and when they are useful.
Bob . . .
________________________________________________________________________________
| From: | "Gabe A Ferrer" <ferrergm(at)bellsouth.net> |
| Subject: | Hobbyair Respirator For Sale |
Hobbyair Buddy System with 2 Direct Feed Hoods #HBBUDDF
40 Foot Hose for Hobbyair
Will sell for $280 plus shipping. Paid $561. Used about seven times. Mostly for
priming a few parts.
Please contact me off list if interested
Gabe A Ferrer
RV6 N2GX 72 hours
South Florida
Email: ferrergm(at)bellsouth.net
Cell: 561 758 8894
Night Phone: 561 622 0960
Fax: 561 622 0960
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Jim,
>I have the solid state unit from B&C. The one that comes with the goose neck
>light. It's small and dims 4 or 5 outputs. Works well with LEDS, not
>expensive, and much easier than making one.
>John Slade
That's the 0.5A version. Exactly the same electronics as
all other sizes, just no heatsink. This is an approximate
equal to Van's sink-less product.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
> > Is there a solid state dimmer available yet that only uses
> > the power needed to light the bulbs without spilling over
> > excess as heat?
>
>I don't know of any for the aircraft industry, but they're not hard to
>build on a piece of perfboard. They're called "switching" or "switch mode"
>power supplies. They're also much more efficient - linear regulators
>dissipate any excess power as heat, so you use the same amount of power
>(plus a small margin) as you would have used at full brightness. Switching
>regulators only have that little margin, so at maximum dim you're using
>very little power.
>
>For instance, Maxim's MAX8545 is $0.92 in bulk (probably a little over a
>buck in single-unit quantities), and have a 2.7V-28V input range. The
>first page of their spec sheet has a sample application circuit that you
>could probably put on a perfboard in an afternoon's work, if you know how
>to read a schematic. It's got about 10 parts, which is more than the
>linear regulator, but if you were building it yourself you'd probably
>still end up saving money.
>
>They are NOT a panacea, however. Switch-mode regulators work by running an
>oscillator, which can put out noise that causes all sorts of trouble with
>other devices. You can eliminate much of this noise by putting the circuit
>in a shielded enclosure, if you're careful. The problem is that "switching
>artifacts" (more noise) can still appear on the output, so all those wires
>to your lights can act like antennae and radiate that noise. It's possible
>to eliminate even this with a good choke design, but that's not exactly a
>beginner design - you would need to tune it for the 300kHz switching
>frequency and possibly a few harmonics.
>
>All things considered, I'd stick with a linear design like B&C's unless
>you have a good reason to switch. Heat is an easier problem to deal with
>than noise.
Well considered advice sir . . . that's why the
offerings from AEC and now B&C are linears. I've
considered some switchmode regulator designs over
the years but haven't convinced myself that they're
good value yet . . . and with the lighting current
requirements going DOWN instead of up by using LEDs,
the switchmode dimmers may never make it to the
B&C catalog.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Battery Contactor vibration problem |
>
>
>I'm powering my Aerosance FADEC system directly from the battery busses
>via fusible links - no contactor involved.
good for you . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Source for BNC adapters? |
>
>Bob or anyone: Does anyone know of a source for the type of BNC adapter
>that Garmin uses in their new transponders and nav/com units (other than
>direct from Garmin that is). These are the type that install in the
>chassis with a
>snap ring and have a plug in socket on the inside to mate with the unit and a
>BNC jack on the outside.
>
>I want to replace the solder type antenna coax snap ring adapters that came
>with my KX-125. I called John Stark, but he said he has been looking for
>them
>also with no success so far.
I'm not familiar with this part. Got a picture?
Bob . . .
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
Chad posted an excellent description of switching (PWM) type dimmers.
I would like to add that linear voltage regulators such as the LM317 (one of
those parts you really need to know about) give some great advantages over a
rheostat potentiometer in dimming applications.
Let's say you have a 15 Volt supply that you want to "dim" to 10V using a
rheostat. If the current is 1A that's 10W for the bulb and 5W dissipation in
the rheostat. Or you could just use a 5 ohm resistor if you are happy with
the 10W.
So why use a voltage regulator?
It's cheaper, smaller, lighter, and the output voltage won't noticeably
change if you add or subtract load or if the input voltage changes. You can
easily dump the heat where you want. You can remotely control it. You can
easily couple it electronically to other devices. It will outlast the
rheostat. A dozen other reasons....
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
________________________________________________________________________________
| From: | "Bob Kuc" <bkuc1(at)tampabay.rr.com> |
Jim,
I am doing the same thing on my velocity. However, I put my largish LEDs in
the overhead console. I have three of them that light up the whole panel.
While I am not flying yet, I have sat in the garage with all the lights out
and it does light up the panel very nicely, but not that brightly. I am not
planning on putting a dimmer on. If you look at Jim Weir's site, he had an
article that used an op amp to oscillate to get a higher voltage through the
LEDs. I believe that the schematic did contain a pot for dimming it if
needed. You should be able to use that. The board should not be big at
all.
> I was thinking about using largish LEDs mounted under the glare shield to
> shine on my panel.
Bob
---
________________________________________________________________________________
| Subject: | Re: Battery Contactor vibration problem |
| From: | Vince Ackerman <vack(at)mac.com> |
I guess I'll look into making a battery direct bus to run the Fadecs,
ign packs and fuel pumps, although it would be pretty much negating the
reason I put the contactor in there in the first place. Not much left
to be switched by a contactor. I wanted to be able to remove all power
from the aircraft busses, for several reason one of which was to try to
reduce electrolysis problems with the coolant and aluminum
block/radiator. On the plus side, leaving it as is, even if I lost the
contactor the alternator would still be providing power to the bus as
long as the engine was running. If it isn't , then I don't need them
anyway : ). How would I wire the battery bus / essential bus to be
powered by the alternator/battery in normal mode, powered by the
battery if the alternator died, and powered by the alternator alone if
the contactor failed? Guess I'll spend some time looking at appendix
Z. Wonder if there's a way to make a warning light that tells you the
contactor has failed (powered by the alternator)? I don't have a lot of
space on this thing to add components or modify the electrical system.
The electrical busses are contained in the overhead switch panel which
is only 12 x 8 inches.
Thanks for your ideas
Vince
On Tuesday, October 21, 2003, at 07:13 AM, Robert L. Nuckolls, III
wrote:
>
>
> There's a big difference between vibration and shock in terms
> of intensity and total energy of the stimulus. You're not
> going to see this interruption happen in normal operation
> even in a helicopter . . . now, if you hit the side of a
> mountain . . .
>
> ANY accessory needed for engine operation should run
> from a battery bus . . . and ESPECIALLY when the accessory is
> known to be ill-prepared to live in the real world of
> aircraft. If Rotorway has told you their FADEC is so
> afflicted, then this reinforces my not so humble opinion
> of their power distribution architecture.
>
> Bob . . .
>
________________________________________________________________________________
| From: | "Stucklen, Frederic IFC" <Fred.Stucklen(at)UTCFuelCells.com> |
Listers,
I've tested and installed into my new RV-6A a digital dimmer from Carling
Technologies. It will easily switch 10A loads, has negligible heat output,
is small, and only has three wires (Power, Ground, & Output). Testing has
shown that they do not cause any radio interference.... The part number is
LD-3A1CC1-3AA-FE-1FC. The spec sheet can be found at:
http://www.carlingtech.com/pdf/ld_series.pdf
The Carling technologies website gives distributor names. I got mine as a
sample, but they should be in under $50.00 retail....
This was a nice find relative to constructing my own as I did in the last
RV. (Simple low frequency 555 timer circuit driving a MOSFET switch, with
controlled rise/fall times). The carling dimmer's waveforms were very
similar to what I had built, and the package is much smaller. The only
difference is that the Carling unit has 10 distinctive intensity setting,
while mine used a potentiometer.... Turns out to not be a big deal in the
cockpit......
I'm using two of these in a full IFR implementation......
Fred Stucklen
RV-6A N925RV 65 Hours
Subject: Re: Dimmers
From: Jim Daniels
Date: 2003/10/20 Mon PM 09:58:16 EDT
> Subject: Re: AeroElectric-List: Dimmers > >
Is there a solid state dimmer available yet that only uses the power needed
to light the bulbs without spilling over excess as heat?
________________________________________________________________________________
| From: | Canyon <steve.canyon(at)verizon.net> |
| Subject: | Re: Dimmers -- and LED trends |
Robert L. Nuckolls, III wrote:
>... and with the lighting current requirements going DOWN instead of
>up by using LEDs, the switchmode dimmers may never make it to the B&C
>catalog.
---
Hi Bob and All,
This is what I'm now considering -- LEDS White, RS supplied as
superbright, 1100 mcd, 3.64 VDC, 0.020 A. I have no comparison in my
memory to tell me whether this is the LED most are using for this
application but it sounds like it could be. As a prelude to use in an
RV, I'm thinking of fabricating a replacement for some small halogen
12VDC under cabinet counter lights in the kitchen. If this works as I
expect, then onto the RV application.
Any advice as to whether this is the best choice for white LEDS from
RadioShack or is there a better LED/source?
Thanks
Steve
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Bob, external power receptacle |
><joberst@cox-internet.com>
>
>Bob, I put your ground power circuit (without the indicator) into my
>Glasair. One morning, I came into my hangar and found the airplane battery
>dead.
>
>The problem was that if you charge your battery, and then unplug the charger
>without pulling out the controlling circuit breaker, the charging contactor
>stays energized (and therefore drawing current) even with the master battery
>switch off. This is an easy mistake to make.
That is an operational disadvantage of the single-pin, Piper
style ground power connector . . . if a 3-pin, mil-spec device,
the ground power contactor can be automatically force off when
the plug is pulled.
Yes . . . there are a number of switches in most airplanes that
that will run the battery down if left ON. To drive down probability
of the scenario you describe (1) I called out a switch-breaker (the
only time I've ever found this device REALLY useful) so that it
can be perceived and treated like a switch. (2) I added a ground
power energized annunciator light (which would be illuminated
any time the ground power contactor is closed irrespective of
the power source).
When one walks away from the airplane, whether post-flight
or post-maintenance, the use of a checklist . . . or at least
a scan of the panel to make sure nothing is lit up is a good
thing to do.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Battery Contactor vibration problem |
>
>I guess I'll look into making a battery direct bus to run the Fadecs,
>ign packs and fuel pumps, although it would be pretty much negating the
>reason I put the contactor in there in the first place. Not much left
>to be switched by a contactor.
It's a backup disconnect for a stuck starter contactor. It's
a means for
> I wanted to be able to remove all power
>from the aircraft busses, for several reason one of which was to try to
>reduce electrolysis problems with the coolant and aluminum
>block/radiator.
don't understand how cold wiring helps avoid airframe corrosion . . .
> On the plus side, leaving it as is, even if I lost the
>contactor the alternator would still be providing power to the bus as
>long as the engine was running.
> If it isn't , then I don't need them
>anyway : ). How would I wire the battery bus / essential bus to be
>powered by the alternator/battery in normal mode, powered by the
>battery if the alternator died, and powered by the alternator alone if
>the contactor failed? Guess I'll spend some time looking at appendix
>Z.
For a single alternator, electrically dependent engine
flying machine, Figure Z-11 with a second battery is my
suggested architecture. Each pump/fadec combo runs from its
own battery bus. If this is a day/vfr only machine, then
you probably don't need the ebus . . . Given what I've
studied so far and based on the present state of our
conversation, here's how I think I'd wire MY helicopter.
http://www.aeroelectric.com/articles/Appendix_Z_Drawings/Z11H_Rotorway.pdf
Bob . . .
> Wonder if there's a way to make a warning light that tells you the
>contactor has failed (powered by the alternator)? I don't have a lot of
>space on this thing to add components or modify the electrical system.
>The electrical busses are contained in the overhead switch panel which
>is only 12 x 8 inches.
Hmmmm . . . the "buses" can be fuseblocks mounted anywhere. A failure
tolerant system shouldn't impact the present switch arrangements. I'm
REALLY skeptical of the fuse sizes called out on the Rotorway drawing.
It would be useful to have some real engineering data on current draw
for the various systems.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Jim,
>I am doing the same thing on my velocity. However, I put my largish LEDs in
>the overhead console. I have three of them that light up the whole panel.
>While I am not flying yet, I have sat in the garage with all the lights out
>and it does light up the panel very nicely, but not that brightly. I am not
>planning on putting a dimmer on. If you look at Jim Weir's site, he had an
>article that used an op amp to oscillate to get a higher voltage through the
>LEDs.
??? Even the highest voltage LEDs are on the order of 4 volts. Can
you describe why some kind of "boost" was necessary?
Bob . . .
________________________________________________________________________________
| From: | John Schroeder <jschroeder(at)perigee.net> |
Bob -
Can you confirm that it is ok to use this design of yours with LED's. For
example, with a red cluster and white cluster in an overhead cabin flood
light. Or with a string of blue-green LED's under the glare shield as
panel floods.
Thanks,
John
>> I have the solid state unit from B&C. The one that comes with the goose
>> neck
>> light. It's small and dims 4 or 5 outputs. Works well with LEDS, not
>> expensive, and much easier than making one.
>> John Slade
>
> That's the 0.5A version. Exactly the same electronics as
> all other sizes, just no heatsink. This is an approximate
> equal to Van's sink-less product.
>
> Bob . . .
________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
| Subject: | Re: Dimmers -- and LED trends |
Steve
>This is what I'm now considering -- LEDS White, RS supplied as
>superbright, 1100 mcd, 3.64 VDC, 0.020 A.
>Any advice as to whether this is the best choice for white LEDS from
>RadioShack or is there a better LED/source?
Check eBay for leds. These guys sell white leds (and other colors) for
cheap!
Example of price---100 Ultra White LED 5mm 7000mcd Free Shipment $28.
That's $0.28 each! 1000 pc for $190. $0.19 each!
cwithk--- Chi Wing LED product shop
deidynamic2000--- Dynamic Electronics and IT Products
hkcitytrader--- HKCityShop
The higher priced 5 mm white leds are now around 12000 mcd!
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
I'm not going to buy my kids an encyclopedia. Let them walk to school like I
did.
--Yogi Berra
________________________________________________________________________________
| Subject: | Re: Track width on PCB |
----- Message d'origine -----
De : "David E. Nelson"
:
Envoy : mercredi 15 octobre 2003 17:46
Objet : Re: AeroElectric-List: Track width on PCB
>
>
> Hi Gilles,
>
> I did a google seach (pcb track width current amps) and found a PCB track
width
> calculator:
>
> http://www.geocities.com/CapeCanaveral/Lab/9643/TraceWidth.htm
>
> Regards,
> /\/elson
Thanks to all who responded,
Regards
Gilles
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Magnetos and preflight testing . . . |
>Comments/Questions: Hi Bob,
> A magneto clarification Question-----when you select left mag on a
> mag check,Are you grounding out the left mag and getting a mag drop
> reading from the right mag,and vice versa or am I totatally confused and
> miseducated about mag operating concept?Please educate me on this topic
> and/or direct me to where I can get a layman's explanation on how this
> all works.
Let's talk about "mag drop" as a test data point.
The speed at which a flame front progresses across
the top of a piston is a function of mixture and
pressure but mostly pressure. The higher the
pressure, the faster the burn. Given the relatively
large diameter pistons in aircraft engines -AND-
location of plugs on opposite sides, there is an
effective change in ignition timing depending on
whether one or two ignition systems are in operation.
When you light TWO fires at opposite sides of the
piston, two flame fronts meet sorta in the middle
with total ignition happening sooner than if you
light the fire at one side only where a single flame
front has to go all the way across the top of piston.
Depending on mixture and the octane rating of the
fuel, you can experience a huge increase in flame
front velocity. Once the fire is lighted, pressures
climb very quickly due to heat released as part of
the combustion process. If octane rating is too low,
the pressure front (travels faster than flame front)
drives pressures in un-burned mixture so high that it
ignites all at once - the explosion is called detonation.
Diesel engines are designed to WORK in this mode of
ignition, 4-cycle gasoline engines break in this mode
of operation . . .
Magnetos, as fixed timing devices, must be timed
so that under worst case conditions (full throttle,
lowest quality fuel, sea-level operation, highest
temperatures, etc, etc) the timing is not so advanced
that detonation will happen. This setting has to
consider the effective advance in timing that
occurs when two magnetos light fires on both sides
of the piston. Needless to say, while the engine
will run at altitude on one magneto, the low manifold
pressures combined with retarded effective timing
will produce a significant decrease in performance.
This is where the electronic ignition with variable,
scheduled timing can stand head-n-shoulders above
the lowly farm tractor ignition system.
During a so-called magneto test during preflight,
we're shown how to explore TWO aspects of magneto
operation. At some RPM higher than idle but with still
relatively low manifold pressures we shut off one
mag at a time. Two things are observed during single
magneto operation: (1) We see that the mag still running
is working and that all plugs are firing . . . (2) we
see a slight drop in RPM due to effective retardation
of ignition timing during single-ignition operation.
Then, we repeat the observation on the other
mag. Noting magnitude of drop is a rough check
of total effective timing . . . noting the same RPM
drop for each mag says they're well synchronized
to each other.
Then comes an potential for confusion when trying
to write a squawk describing a magneto problem.
When you turn a key switch to "L" (engine runs on
left mag only) and the engine stumbles . . . you
can confidently write "left magneto tests bad on
run-up". If you have toggle switches, testing the
LEFT mag requires you turn OFF the RIGHT mag. It's
a common mistake for a pilot to belive that turning
the switch marked "R MAG" OFF is a test of the right
mag and he/she squawks the wrong mag.
If you have any combination of electronic ignition,
it is possible that the electronic ignition will be
advanced to optimum timing for the engine speed and
manifold pressures during run-up. The important fact
to be gathered by running the engine from one
ignition source at a time is to prove that both
sources are working. RPM notations are dependent
design and programming of the electronic ignition
and may or may not have any significance during
preflight testing.
Bob . . .
________________________________________________________________________________
| From: | "Bob Kuc" <bkuc1(at)tampabay.rr.com> |
Jim wrote an article on how to get more light from an LED. Basically by
flashing the LED at 120 Hz with 1/4 duty you can use higher voltage through
the LED that what it was rated for, the eye sees the brighter light as
steady.
His article can explain it much better that I can. Here is the link to
Jim's article and schematic on how to build it. It does contain a pot to
adjust the brightness http://www.rst-engr.com/kitplanes/KP0010/KP0010.htm
I used this schematic to drive three jumbo defused LEDs that allows me to
light my panel from my overhead console. While I was testing this in my
garage on late evening, my wife decided to go to bed, looked in the garage
and saw that it was dark, locked it up with me still in the garage.
Needless to say, scared the begeezus out of here when I started to bang on
the garage door :-)
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Dimmers
>
> >
> >Jim,
> >I am doing the same thing on my velocity. However, I put my largish LEDs
in
> >the overhead console. I have three of them that light up the whole
panel.
> >While I am not flying yet, I have sat in the garage with all the lights
out
> >and it does light up the panel very nicely, but not that brightly. I am
not
> >planning on putting a dimmer on. If you look at Jim Weir's site, he had
an
> >article that used an op amp to oscillate to get a higher voltage through
the
> >LEDs.
>
> ??? Even the highest voltage LEDs are on the order of 4 volts. Can
> you describe why some kind of "boost" was necessary?
>
> Bob . . .
>
---
________________________________________________________________________________
On 21 Oct 2003 at 8:35, Jim Sower wrote:
>For those who need to mix and match LED with Incondesent bulbs, check out this
site.
http://www.a-and-t-labs.com/K11_Dimmer/index.htm
peter
________________________________________________________________________________
| From: | Canyon <steve.canyon(at)verizon.net> |
| Subject: | Re: Dimmers -- and LED trends |
Eric M. Jones wrote:
>Check eBay for leds. These guys sell white leds (and other colors) for
>cheap!
>Example of price---100 Ultra White LED 5mm 7000mcd Free Shipment $28.
> That's $0.28 each! 1000 pc for $190. $0.19 each!
Thanks, Eric -- I don't know squat about candlepower, at least from
practical experience. Though the 1100mcd sounded low though.
>cwithk--- Chi Wing LED product shop
> deidynamic2000--- Dynamic Electronics and IT Products
> hkcitytrader--- HKCityShop
>
>The higher priced 5 mm white leds are now around 12000 mcd!
I'll check these out -- thanks again!
Steve
________________________________________________________________________________
| From: | "Dawson, Bill" <Bill.Dawson(at)pepperdine.edu> |
| Subject: | Re: LED Position Lights |
-----Original Message-----
From: Shaun Simpkins [mailto:shauns(at)hevanet.com]
Subject: AeroElectric-List: Re: LED Position Lights
>You're close. The emitters appear to be the 1W Luxeon Star-O in a custom
heat sink/circuit board.
>These units run at 350mA and 4.0V worst case ( about 3.3V for red ), so 7
of them in series just
> fit in a 28V system. No 28-to-56V step-up unit required. The Star-O,
because of its optics,
>can put out a really bright beam - over 180 candela.
Whelen confirms that the 70875 position lights mentioned in this thread over
the last few weeks are
using the Luxeon Star-O emitters. The housing contains only a heat sink,
and the emitters are derated
20% for maximum reliability. The list price of these items is about $460 -
expect the street price to be
around $250. Whelen will be changing over its entire aviation filament-based
illuminators
to LED-based over the next two years or so. The economies of scale of its
emergency vehicle and
industrial divisions are allowing its aviation division to modernize its
products. A/C mfgs are chomping
at the bit, but more for the install-and-forget reliability rather than the
power savings.
Shaun
________________________________________________________________________________
I looked around on his website, and didn't see any article boosting the
"voltage" to an LED... and as you say, it really wouldn't do much
(except posssibly overheat the current-limiting resistor I suppose...)
However, if he was indeed making an *oscillator*, there is a trick to
make the LED *appear* to be brighter, by driving it at some fractional
duty cycle at a multiple of the current... so if an LED is rated to 20mA
at 100% duty cycle, you can drive it at 200mA at 10%... the human eye
will perceive it to be brighter, even though the total power is the same.
Come to think of it, that could be a neat way to make a dimmer for LEDs...
-John R.
Robert L. Nuckolls, III wrote:
>
>
>
>>
>>Jim,
>>I am doing the same thing on my velocity. However, I put my largish LEDs in
>>the overhead console. I have three of them that light up the whole panel.
>>While I am not flying yet, I have sat in the garage with all the lights out
>>and it does light up the panel very nicely, but not that brightly. I am not
>>planning on putting a dimmer on. If you look at Jim Weir's site, he had an
>>article that used an op amp to oscillate to get a higher voltage through the
>>LEDs.
>>
>>
>
> ??? Even the highest voltage LEDs are on the order of 4 volts. Can
> you describe why some kind of "boost" was necessary?
>
> Bob . . .
>
>
>
>
________________________________________________________________________________
rv-list(at)matronics.com
| Subject: | B&C regulator for sale |
| From: | Bob Bittner <rbittner(at)us.ibm.com> |
10/21/2003 08:10:23 PM,
Serialize complete at 10/21/2003 08:10:23 PM
Hi all.
I ordered a B&C LR-3 14V alternator controller / OV protection, but I'm
going to use an internally regulated alternator instead. It's still
new-in-box, unopened condition. I could send it back to Aircraft Spruce,
but I thought I might just as well see if anyone here wants it. I can
ship it to you without sales tax or shipping charge (pay via PayPal) and
probably a bit sooner... otherwise, I'll just send it back to AS.
Bob B
________________________________________________________________________________
| From: | Jim Sower <canarder(at)frontiernet.net> |
<... much more efficient - linear regulators dissipate any excess power as heat,
so you use the same amount of power ...>
<... All things considered, I'd stick with a linear design like B&C's ...>
I thought a linear regulator varied the voltage to the lights and wouldn't work
on a LED - that they are either on or off and you need to flash them to make
them look dim. Could I use a linear regulator? And how is it different from
a pot?
Wondering if I'm asking the right questions now ... Jim S.
"Robinson, Chad" wrote:
>
> > Is there a solid state dimmer available yet that only uses
> > the power needed to light the bulbs without spilling over
> > excess as heat?
>
________________________________________________________________________________
| From: | "Robinson, Chad" <crobinson(at)rfgonline.com> |
> I looked around on his website, and didn't see any article boosting the
> "voltage" to an LED... and as you say, it really wouldn't do much
> (except posssibly overheat the current-limiting resistor I suppose...)
John, you made a good point about pulse width modulation (PWM) to make LEDs seem
brighter at the same power levels, but I'd like to respond to this other point.
Yes and no. A higher voltage WOULD make the LED brighter, because it's the
difference between the supply voltage and the LED's forward voltage drop that
determines the drop across the resistor, and thus the current flow through the
whole shebang.
Normally, you look at the data sheet for the LED and see that it has, say, a 1.7V
drop and a max current rating of 50mA. So maybe you knock off 5mA to keep them
living as long as possible and end up with 45mA. Now supposing you have an
"ideal" main bus voltage of 13.8V. That means you're dropping 12.1V across the
resistor. E = I * R, so 12.1V = 0.045 * R. Solving for R, you get a resistance
of about 269 ohms. Interestingly enough, you can find 270 ohm resistors fairly
readily (red purple brown), so that makes a good size.
[ I didn't mean for that explanation to patronize anybody, but it's been a while
since I last saw it mentioned, and it's sort of a regular question so I figured
I'd make a round of it for the benefit of the lurkers. Bob, maybe you should
make a FAQ? =) ]
I think Bob's point was that even the biggest LEDs (and these are monsters, please
note) only have a 4V drop, so there's still plenty of room to calculate decent
limiting resistors for this (200 ohms gives you roughly 50mA here, for instance).
So it's a puzzle as to why somebody would need to boost the voltage.
Normally, all that matters is that you're a certain amount above the forward voltage
drop of the diode.
May I take a guess? Betcha these aren't for LEDs. Switch mode regulators are quite
similar to the inverters used to power EL light strips, and I've seen a few
mentions of those mentioned recently. They require AC to excite them, usually
at anywhere from 100-400 volts, so it's definitely a "step up" application.
Also, I looked at RST's site, at Jim Weir's articles, and it looks like his "mother
of all lamp dimmers" was designed for lamps, not LEDs (although it could
certainly handle both, to an extent).
There are some advantages to both designs, but gosh, look at all the parts. =)
With LEDs drawing as little power as they do, it's probably overkill. (That's
a hypocritical statement for anybody who's seen my glass cockpit design, but what
the hey. )
Regards,
Chad
________________________________________________________________________________
| From: | Jim Sower <canarder(at)frontiernet.net> |
Bob,
It looks at this point like I'll be getting the B&C unit everyone's suggesting.
It's also becoming apparent that I was maybe posing the question based on false
premises around how stuff works.
Bob Kuc wrote:
>
> Jim,
> I am doing the same thing on my velocity. However, I put my largish LEDs in
> the overhead console. I have three of them that light up the whole panel.
> While I am not flying yet, I have sat in the garage with all the lights out
> and it does light up the panel very nicely, but not that brightly. I am not
> planning on putting a dimmer on. If you look at Jim Weir's site, he had an
> article that used an op amp to oscillate to get a higher voltage through the
> LEDs. I believe that the schematic did contain a pot for dimming it if
> needed. You should be able to use that. The board should not be big at
> all.
________________________________________________________________________________
Well, I was trying to keep my reply uncharacteristically simple and
direct... yes, a higher supply voltage will increase the Vdrop across
the resistor, which increases the current in both the resistor and the
LED, which increases the heat dissipated by the resistor, and light
output of the LED... to a point. (LEDs have ratings for a reason; too
much and they will indeed glow more brightly - for a while. Maybe even
REAL bright. and then, real DARK! :-)
But in any event, although I'm not certain what Bob's "???" specifically
referred to (you're probably right), I was just thinking that if you
wanted to boost an LED's output, you generally don't do it by throwing
more voltage at it - and if you did, using an oscillator to do it is the
long way 'round to end up at the same problem - the higher voltage
across the resistor generates a lot of wasted heat, which is what we're
trying to avoid.
I vote for the PWM as the most likely explanation for a design involving
an oscillator.Yes, it's somewhat more complex (although a 556, a few
caps and resistors will do the trick nicely I should think), but does
not create much excess heat, and can function both as a dimmer and a
"booster".
I'd like to find the article though.
-John
Robinson, Chad wrote:
>
>
>
>>I looked around on his website, and didn't see any article boosting the
>>"voltage" to an LED... and as you say, it really wouldn't do much
>>(except posssibly overheat the current-limiting resistor I suppose...)
>>
>>
>
>John, you made a good point about pulse width modulation (PWM) to make LEDs seem
brighter at the same power levels, but I'd like to respond to this other point.
Yes and no. A higher voltage WOULD make the LED brighter, because it's the
difference between the supply voltage and the LED's forward voltage drop that
determines the drop across the resistor, and thus the current flow through the
whole shebang.
>
>Normally, you look at the data sheet for the LED and see that it has, say, a 1.7V
drop and a max current rating of 50mA. So maybe you knock off 5mA to keep
them living as long as possible and end up with 45mA. Now supposing you have an
"ideal" main bus voltage of 13.8V. That means you're dropping 12.1V across the
resistor. E = I * R, so 12.1V = 0.045 * R. Solving for R, you get a resistance
of about 269 ohms. Interestingly enough, you can find 270 ohm resistors fairly
readily (red purple brown), so that makes a good size.
>
>[ I didn't mean for that explanation to patronize anybody, but it's been a while
since I last saw it mentioned, and it's sort of a regular question so I figured
I'd make a round of it for the benefit of the lurkers. Bob, maybe you should
make a FAQ? =) ]
>
>I think Bob's point was that even the biggest LEDs (and these are monsters, please
note) only have a 4V drop, so there's still plenty of room to calculate decent
limiting resistors for this (200 ohms gives you roughly 50mA here, for instance).
So it's a puzzle as to why somebody would need to boost the voltage.
Normally, all that matters is that you're a certain amount above the forward
voltage drop of the diode.
>
>May I take a guess? Betcha these aren't for LEDs. Switch mode regulators are quite
similar to the inverters used to power EL light strips, and I've seen a few
mentions of those mentioned recently. They require AC to excite them, usually
at anywhere from 100-400 volts, so it's definitely a "step up" application.
Also, I looked at RST's site, at Jim Weir's articles, and it looks like his "mother
of all lamp dimmers" was designed for lamps, not LEDs (although it could
certainly handle both, to an extent).
>
>There are some advantages to both designs, but gosh, look at all the parts. =)
With LEDs drawing as little power as they do, it's probably overkill. (That's
a hypocritical statement for anybody who's seen my glass cockpit design, but
what the hey. )
>
>Regards,
>Chad
>
>
>
>
________________________________________________________________________________
| From: | Alex Balic <alex157(at)direcway.com> |
Does anyone foresee any value in twisting the strobe wiring to reduce RF
output? I know that most of the interference comes from the power supply,
and not the wire, but it seems that the high voltage pulsing within the
strobe head supply wire would cause some kind of output..... Would twisting
the wires even have an effect in this situation?
________________________________________________________________________________
| From: | Alex Balic <alex157(at)direcway.com> |
| Subject: | using the battery buss |
Bob mentioned that all electronic engine controls should be run from the
Battery bus - including the fuel pumps- is the purpose of this primarily to
eliminate the contactor as a source of unwanted intermittent interruption?
________________________________________________________________________________
| From: | "Robinson, Chad" <crobinson(at)rfgonline.com> |
> <... much more efficient - linear regulators dissipate any
> excess power as heat, so you use the same amount of power ...>
> <... All things considered, I'd stick with a linear design
> like B&C's ...>
> I thought a linear regulator varied the voltage to the lights
> and wouldn't work on a LED - that they are either on or off
> and you need to flash them to make them look dim. Could I
> use a linear regulator? And how is it different from a pot?
> Wondering if I'm asking the right questions now ... Jim S.
Nope, you can use a linear regulator here. Treat an LED like a light bulb with
some special characteristics, namely, voltage has to be above the forward voltage
drop or it won't turn on, and they require a current limiting resistor to
control the current flow. It's actually the CURRENT flow that determines the LED's
brightness, but we know through Ohm's law that they're related: voltage current
* resistance.
Suppose you flipped what I said earlier about changing the resistance to make it
dimmer or brighter? Instead, you boost or drop the voltage, which is what the
regulator does? The current will naturally increase or decrease, and the LED
will get brighter or dimmer.
LEDs really have two big advantages IMHO. First, they last a very long time - not
forever, but it feels like it compared to a light bulb. They'll outlast your
plane, anyway - we're talking 100,000 hours here, depending on how much current
you shove through them, and many manufacturers list lifetime as "time to half
brightness", not even when the thing actually dies completely. Second, they
don't consume very much current all things considered, so they can be more efficient
(little to no waste heat).
There are limits to how bright they can get, though. Jeff Wilson (www.jbwilco.com/Cozyweb), a gentleman I'm collaborating with on my glass cockpit display (www.lucubration.com, although I've made progress I haven't had a chance to log - our firstborn is 7 weeks out now!) is an engineer with ST (to establish his credentials) and spent a great deal of time experimenting with arrays of white LEDs to replace wing lights. He wasn't able to find a satisfactory and cost-effective solution, at least not so far.
Regards,
Chad
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: using the battery buss |
>
>Bob mentioned that all electronic engine controls should be run from the
>Battery bus - including the fuel pumps- is the purpose of this primarily to
>eliminate the contactor as a source of unwanted intermittent interruption?
That's one reason . . . but a small one.
When I walk up to a J-3 and turn ON two toggle switches, the
mags are "hot" and the engine will run. When I set down in
a Sundowner and turn the keyswitch to "BOTH", I can prop the
engine and it will run. One airplane has no electrical system,
the other has an electrical system . . . but in neither
case does the engine depend on the electrical system for
operation. When I walk up to any rental airplane available
to me, I know (because of what I carry in my flight bag)
that as long as the engine runs, I'll arrive comfortably
at an airport of my choice irrespective of any failure
in the electrical/avionics systems of that airplane.
Now, lets add some product that improves engine performance
but requires electrical power to function. Why would one willingly
give up system reliability features to acquire a modicum of
performance features? As a former owner/operator of a rental
fleet, I can tell you that I wouldn't even consider modifying
one of the airplanes with electronic ignition and/or a FADEC system.
Why? Return on investment just isn't there. Even on an airplane
that rents 30-40 hours a month, I couldn't pay for a certified
FADEC in any reasonable period of time in fuel savings. I'm
not sure the numbers would justify putting a $low$ Jeff or Klaus
ignition system on a rental machine.
All of these "enhancements" require electrical power to keep
the engine running. Therefore, any engine so fitted should
have enough independent sources of power to keep probability
of electrically induced stoppage to some level on a par
with dual magnetos of yore.
(1) We know that parts count is inversely related to
reliability. So, it behooves us to MINIMIZE parts count
between electrically critical engine components and
their power sources.
(2) It's also useful to keep engine operation as independent
as possible from electrical system operation. Suppose you
smell bad stuff in the cockpit and it's not gasoline
fumes? First reaction is to shut down the DC power master
switches . . . it's really handy if you can do this and
not have the engine continue to run.
With one or two $LOW$ ignition systems, this is pretty
easy. FADECs are more problematic. I don't know what the
REAL current requirements are for these systems but some
of the wire and fuse sizes specified by the system designers
are scarry.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: twisted wiring |
>
>Does anyone foresee any value in twisting the strobe wiring to reduce RF
>output? I know that most of the interference comes from the power supply,
>and not the wire, but it seems that the high voltage pulsing within the
>strobe head supply wire would cause some kind of output..... Would twisting
>the wires even have an effect in this situation?
The shielded-triple wire supplied in the installation kits
for strobes IS twisted . . . but if it were not, it wouldn't
make any difference. Just the fact that the wires between strobe
heads and power supplies are closely bundled breaks 99% of
the noise propagation potential. Shielding takes out the
majority of the last 1%. Wether or not it's twisted is of
no practical consequence.
Most noise problems with strobes is related to audio rate
CONDUCTED noise coming out the power supply leads and propagating
around the airplane on the bus. When encountered, this noise
is easy to fix.
Bob . . .
________________________________________________________________________________
| From: | "Ashcraft, Keith -AES" <Keith.Ashcraft(at)itt.com> |
Hi All,
Another way to control a LEDs brightness is to modulate its "ON" time. Still limit
the current to around 20mA, but modulate the "ON" time. PWM (pulse width modulation)
is what it is referred to. A 555 timer chip, will work, but now you
are getting into a more complicated scenario, and is it worth it?
Keith
Zenith CH701
Tail 98% --kit
All else ----scratch
N 38.9947
W 105.1305
Alt. 9,100'
Robinson, Chad wrote:
<... much more efficient - linear regulators dissipate any
excess power as heat, so you use the same amount of power ...>
<... All things considered, I'd stick with a linear design
like B&C's ...>
I thought a linear regulator varied the voltage to the lights
and wouldn't work on a LED - that they are either on or off
and you need to flash them to make them look dim. Could I
use a linear regulator? And how is it different from a pot?
Wondering if I'm asking the right questions now ... Jim S.
Nope, you can use a linear regulator here. Treat an LED like a light bulb with
some special characteristics, namely, voltage has to be above the forward voltage
drop or it won't turn on, and they require a current limiting resistor to
control the current flow. It's actually the CURRENT flow that determines the LED's
brightness, but we know through Ohm's law that they're related: voltage current
* resistance.
Suppose you flipped what I said earlier about changing the resistance to make it
dimmer or brighter? Instead, you boost or drop the voltage, which is what the
regulator does? The current will naturally increase or decrease, and the LED
will get brighter or dimmer.
LEDs really have two big advantages IMHO. First, they last a very long time - not
forever, but it feels like it compared to a light bulb. They'll outlast your
plane, anyway - we're talking 100,000 hours here, depending on how much current
you shove through them, and many manufacturers list lifetime as "time to half
brightness", not even when the thing actually dies completely. Second, they
don't consume very much current all things considered, so they can be more efficient
(little to no waste heat).
There are limits to how bright they can get, though. Jeff Wilson (www.jbwilco.com/Cozyweb), a gentleman I'm collaborating with on my glass cockpit display (www.lucubration.com, although I've made progress I haven't had a chance to log - our firstborn is 7 weeks out now!) is an engineer with ST (to establish his credentials) and spent a great deal of time experimenting with arrays of white LEDs to replace wing lights. He wasn't able to find a satisfactory and cost-effective solution, at least not so far.
Regards,
Chad
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________________________________________________________________________________
| From: | "Eric M. Jones" <emjones(at)charter.net> |
Remember before running off to build some led lights, that leds are DIODES
and they cannot be put in parallel, without a current limiting resistor.
The reasonable way to make an led assembly is to put several leds in series
with ONE limiting resistor.
For example-- if the power supply is 14.5V and the individual led Vf
(voltage drop) is 2 volts, you can string seven of these leds in series with
a series resistor (in this case E=IR; pick the current; 0.5V/.020A=25 ohms).
This string (whose length is limited only by the available drive voltage)
can conveniently be put into a parallel-connected assembly (whose width is
limited only by the available current). Remember to calculate the power
dissipated in the resistor (I x I x R; in this case .02 x .02 x 25=.01W).
The dissipated power in a single led operated from 14.5V at .02A would be
about 30X as much. This often fools first timers.
Squash the notion that leds need to be pulsed to change their intensity.
This errant notion comes from the way digit displays are lighted by
microprocessors. It is also electrically very noisy. Regular leds behave
pretty much like regular filament lamps to changing voltage.
One more thing to watch for! Leds usually have a poor reverse voltage
withstand, usually only 4-5 volts. So you can easily blow them up by reverse
voltage or ESD static.
I don't know what Jim Weir was thinking. It must be hard to come up with an
article every month.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones(at)charter.net
"A man's got to know his limitations."
(Clint Eastwood's Dirty Harry in Magnum Force, 1973)
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
> > I looked around on his website, and didn't see any article boosting the
> > "voltage" to an LED... and as you say, it really wouldn't do much
> > (except posssibly overheat the current-limiting resistor I suppose...)
>
>John, you made a good point about pulse width modulation (PWM) to make
>LEDs seem brighter at the same power levels, but I'd like to respond to
>this other point. Yes and no. A higher voltage WOULD make the LED
>brighter, because it's the difference between the supply voltage and the
>LED's forward voltage drop that determines the drop across the resistor,
>and thus the current flow through the whole shebang.
>
>Normally, you look at the data sheet for the LED and see that it has, say,
>a 1.7V drop and a max current rating of 50mA. So maybe you knock off 5mA
>to keep them living as long as possible and end up with 45mA. Now
>supposing you have an "ideal" main bus voltage of 13.8V. That means you're
>dropping 12.1V across the resistor. E = I * R, so 12.1V = 0.045 * R.
>Solving for R, you get a resistance of about 269 ohms. Interestingly
>enough, you can find 270 ohm resistors fairly readily (red purple brown),
>so that makes a good size.
>
>[ I didn't mean for that explanation to patronize anybody, but it's been a
>while since I last saw it mentioned, and it's sort of a regular question
>so I figured I'd make a round of it for the benefit of the lurkers. Bob,
>maybe you should make a FAQ? =) ]
>
>I think Bob's point was that even the biggest LEDs (and these are
>monsters, please note) only have a 4V drop, so there's still plenty of
>room to calculate decent limiting resistors for this (200 ohms gives you
>roughly 50mA here, for instance). So it's a puzzle as to why somebody
>would need to boost the voltage. Normally, all that matters is that you're
>a certain amount above the forward voltage drop of the diode.
>
>May I take a guess? Betcha these aren't for LEDs. Switch mode regulators
>are quite similar to the inverters used to power EL light strips, and I've
>seen a few mentions of those mentioned recently. They require AC to excite
>them, usually at anywhere from 100-400 volts, so it's definitely a "step
>up" application. Also, I looked at RST's site, at Jim Weir's articles, and
>it looks like his "mother of all lamp dimmers" was designed for lamps, not
>LEDs (although it could certainly handle both, to an extent).
I've looked over Jim's schematic at:
http://www.rst-engr.com/kitplanes/KP0010/KPsch.jpg
This is a variable duty-cycle oscillator driving an array of
switches that modulate current flow through an LED/Resistor
combination.
First, let's consider the LED/Resistor combo at R8, R9, D1
A pair of 180 ohm resistors in parallel yields a combined
resistance of 90 ohms. A single 91 or 100 ohm resistor would
suffice here too . . . it's not apparent why he chooses to
parallel two devices . . . perhaps this was what he had in
the junkbox.
Okay, 14v supply fed to this resistor/lamp combo though a
saturated switch (Q2) says the current through the diode
is (14-2)/90 = 133 milliamperes. So, if the LED is rated
at 30 ma, one might reasonably deduce that maximum duty
cycle for operating at 133 mA PEAK is on the order of
22%
Now the question is, what is the apparent brightness
difference between two LEDs, on operated at 133 mA peak
and 22% and one operated at 30 mA and 100%? We do
know that the tends to be a peak intensity responder.
Its reasonable to infer that the eye might perceive
that the 133/22 lamp is brighter than the 30/100
lamp. 4x as bright? No, just because you whang
a LED at 4x its rated current doesn't mean that you
get 4x light. Even if it were 4x as bright in terms
of measured output, can you look at three lamps of
varying intensity and tell me if #1 is 2x the light
of #2 and #3 is 10x the light output of #1? I suspect
not.
I suspect this article was written some time ago and
perhaps before the virtual flood of high intensity
lamps came onto the market in a variety of colors.
I find it a weak idea to electronically fool our eyes
into believing a barely adequate single LED is superior
to running two or three LEDs . . . it's not like they
are expensive.
The strongest arguments against this technique of
intensity enhancement are: (1) What happens if a component
in the oscillator fails and the system goes to 100%
duty cycle? Do the LED go belly up? Do the resistors
smoke? and (2) what is the relative reliability of
a system that uses a single adjustable duty-cycle
controller for all of the LEDs in the system? One
part can crap and either smoke or shut down the whole
system.
The next revision to lighting chapter in the 'Connection
will touch on LEDs as primary illumination sources for
both annunicators and general panel illumination. If I were
building an airplane today, I find it attractive to
consider making the panel floods from an array of LEDs
powered from its own lithium or alkaline battery pack.
Completely independent of ship's power.
Bob . . .
________________________________________________________________________________
| From: | "Bob Kuc" <bkuc1(at)tampabay.rr.com> |
Jim wrote an article on how to get more light from an LED. Basically by
flashing the LED at 120 Hz with 1/4 duty you can use higher voltage through
the LED that what it was rated for, the eye sees the brighter light as
steady.
His article can explain it much better that I can. Here is the link to
Jim's article and schematic on how to build it. It does contain a pot to
adjust the brightness http://www.rst-engr.com/kitplanes/KP0010/KP0010.htm
I used this schematic to drive three jumbo defused LEDs that allows me to
light my panel from my overhead console. While I was testing this in my
garage on late evening, my wife decided to go to bed, looked in the garage
and saw that it was dark, locked it up with me still in the garage.
Needless to say, scared the begeezus out of here when I started to bang on
the garage door :-)
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: AeroElectric-List: Dimmers
>
> >
> >Jim,
> >I am doing the same thing on my velocity. However, I put my largish LEDs
in
> >the overhead console. I have three of them that light up the whole
panel.
> >While I am not flying yet, I have sat in the garage with all the lights
out
> >and it does light up the panel very nicely, but not that brightly. I am
not
> >planning on putting a dimmer on. If you look at Jim Weir's site, he had
an
> >article that used an op amp to oscillate to get a higher voltage through
the
> >LEDs.
>
> ??? Even the highest voltage LEDs are on the order of 4 volts. Can
> you describe why some kind of "boost" was necessary?
>
> Bob . . .
>
---
________________________________________________________________________________
| From: | John Schroeder <jschroeder(at)perigee.net> |
Chad -
To get relatively uniform dimming/illumination from a linear regulator on
a string of LED's you should have them in parallel. Correct?
Thanks,
John
> Nope, you can use a linear regulator here. Treat an LED like a light
> bulb with some special characteristics, namely, voltage has to be above
> the forward voltage drop or it won't turn on, and they require a current
> limiting resistor to control the current flow.
________________________________________________________________________________
| Subject: | Re: Powering LEDs |
Your numbers are correct in an ideal world - but if the voltage were to
fall to 12.6 or even 12 volts, the LEDs will have less than 1.7 volts
across each one (on average), and they will get *very* dim (luminance is
not linear with voltage)... I'd put no more than 5 in series (given Vled
of 2.0 volts) or maybe even only 4, so that they will always function
even in cases of power anomalies (no, I'm not going to use the word
"emergency"! :-)
But you do make a good point - much simpler than PWM, and not much
wastge heat in the resistor, since it is so much smaller. Of course I
wouldn't do a series string like this with incandescents because of the
relatively high failure rate, but LEDs are so long-lived that I think it
would be acceptable. And if you want redundancy, use two strings of 4
LEDs each, each with a current-limiting resistor of 330 ohms 1/4-watt
resistors (drop of maximum 14.5-8 volts or 6.5 volts/.02A = .13 watts)
-John R.
P.S.: BTW, I googled for "Jim Weir LED" and found the articles - he
actually covers both methods;
<http://www.rst-engr.com/kitplanes/KP0009A/KP0009A.htm> describes series
LED operation, and
<http://www.rst-engr.com/kitplanes/KP0010/KP0010.htm> shows a
dimming/boosting PWM circuit.
I think he's using the LM324 because it probably makes a bit less
electrical noise than a 555, and may be more flexible in drive
capability to multiple transistors (although I'm sure you could adapt a
555 to do something similar, still with fewer parts)
Eric M. Jones wrote:
>
>Remember before running off to build some led lights, that leds are DIODES
>and they cannot be put in parallel, without a current limiting resistor.
>
>The reasonable way to make an led assembly is to put several leds in series
>with ONE limiting resistor.
>For example-- if the power supply is 14.5V and the individual led Vf
>(voltage drop) is 2 volts, you can string seven of these leds in series with
>a series resistor (in this case E=IR; pick the current; 0.5V/.020A=25 ohms).
>
>This string (whose length is limited only by the available drive voltage)
>can conveniently be put into a parallel-connected assembly (whose width is
>limited only by the available current). Remember to calculate the power
>dissipated in the resistor (I x I x R; in this case .02 x .02 x 25=.01W).
>The dissipated power in a single led operated from 14.5V at .02A would be
>about 30X as much. This often fools first timers.
>
>Squash the notion that leds need to be pulsed to change their intensity.
>This errant notion comes from the way digit displays are lighted by
>microprocessors. It is also electrically very noisy. Regular leds behave
>pretty much like regular filament lamps to changing voltage.
>
>One more thing to watch for! Leds usually have a poor reverse voltage
>withstand, usually only 4-5 volts. So you can easily blow them up by reverse
>voltage or ESD static.
>
>I don't know what Jim Weir was thinking. It must be hard to come up with an
>article every month.
>
>Regards,
>Eric M. Jones
>www.PerihelionDesign.com
>113 Brentwood Drive
>Southbridge MA 01550-2705
>Phone (508) 764-2072
>Email: emjones(at)charter.net
>
> "A man's got to know his limitations."
> (Clint Eastwood's Dirty Harry in Magnum Force, 1973)
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Powering LEDs |
>
>Squash the notion that leds need to be pulsed to change their intensity.
>This errant notion comes from the way digit displays are lighted by
>microprocessors. It is also electrically very noisy. Regular leds behave
>pretty much like regular filament lamps to changing voltage.
I don't think this was the foundation of the philosophy. At the
time the article was done, I suspect Jim was trying to increase
perceived brightness by duty-cycle switching power at an elevated
peak level . . . adjusting intensity over the min to max bright
by adjusting duty-cycle from 0% to max bright was a fallout of
the pulsed control philosophy
>One more thing to watch for! Leds usually have a poor reverse voltage
>withstand, usually only 4-5 volts. So you can easily blow them up by reverse
>voltage or ESD static.
I've not found this to be a real toe-stubber. I've run repeated
bench tests applying 30V reverse voltage to high intensity red
and white LEDs with no damage.
>I don't know what Jim Weir was thinking. It must be hard to come up with an
>article every month.
Reading from the text of his article, it WAS his intention
to take advantage of peak handling capabilities of LEDs combined
with characteristics of the human eye to get more "brightness"
without over-stressing the devices . . . a relatively cool idea
if the parts counts and failure modes were not so discouraging.
Bob . . .
________________________________________________________________________________
| From: | "Steve Sampson" <SSampson.SLN21(at)london.edu> |
Why do contactors normally have one side labelled to the battery and the
other to the load? They would appear to be a symmetrical device from the
internal diagram in Bob's book.
The reason for the question is that I am wiring up the firewall of an RV9a
and am using basically diags Z9 and Z24 (to control an internally regulated
alternator). Placement of the contactor to kill the supply from the
alternator means the wiring would be simpler if the device was wired
'backwards'. In fact the current will also flow through it backwards in that
if a contactor is normally handling current flowing from a battery to
devices this contactor will be handling current flowing from an alternator
to a battery.
The specific units concerned are the VANS Master Relay and the VANS ND 60
amp alternator.
________________________________________________________________________________
| Subject: | Substitute for Shoo Goo |
Hi Bob and all,
Shoo goo is not available on this side of the pond. Do you think the regulat
glue supplied with my hot glue gun could be a good replacement ?
Thanks
Gilles Thesee
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Substitute for Shoo Goo |
><Gilles.Thesee@ac-grenoble.fr>
>
>Hi Bob and all,
>
>Shoo goo is not available on this side of the pond. Do you think the regulat
>glue supplied with my hot glue gun could be a good replacement ?
No, hot melts are a whole other attachment technology. The
more generic, industrial equivalent of Shoe Goo is E-6000
offered by Eclectic Products (also makes Shoe Goo). Check with
hardware and craft stores. If push comes to shove, I could
get some and send it to you. This is a unique product with
extra-ordinary capabilities. There are undoubtedly other products
with similar capabilities but I've not researched any.
Bob . . .
________________________________________________________________________________
| From: | dschaefer1(at)kc.rr.com |
Bob ... can you remind me why there are so many diodes on the various
contactors? I'm building the 'all electric' airplane and don't really know
why they are there.
Regards,
David
________________________________________________________________________________
Hey guys,
I've got the solution.
First, use the PWM to brighten the LEDS and keep the life in the 20,000 hour range.
Second, Move to South Florida, you'll never notice the extra heat.
Cheers,
Peter
Well, I was trying to keep my reply uncharacteristically simple and
> direct... yes, a higher supply voltage will increase the Vdrop across
> the resistor, which increases the current in both the resistor and the
> LED, which increases the heat dissipated by the resistor, and light
> output of the LED... to a point. (LEDs have ratings for a reason; too
> much and they will indeed glow more brightly - for a while. Maybe even
> REAL bright. and then, real DARK! :-)
>
> But in any event, although I'm not certain what Bob's "???"
> specifically referred to (you're probably right), I was just thinking
> that if you wanted to boost an LED's output, you generally don't do it
> by throwing more voltage at it - and if you did, using an oscillator
> to do it is the long way 'round to end up at the same problem - the
> higher voltage across the resistor generates a lot of wasted heat,
> which is what we're trying to avoid.
>
> I vote for the PWM as the most likely explanation for a design
> involving an oscillator.Yes, it's somewhat more complex (although a
> 556, a few caps and resistors will do the trick nicely I should
> think), but does not create much excess heat, and can function both as
> a dimmer and a "booster".
>
> I'd like to find the article though.
>
> -John
>
>
> Robinson, Chad wrote:
>
> >
> >
> >
> >
> >>I looked around on his website, and didn't see any article boosting
> >>the "voltage" to an LED... and as you say, it really wouldn't do
> >>much (except posssibly overheat the current-limiting resistor I
> >>suppose...)
> >>
> >>
> >
> >John, you made a good point about pulse width modulation (PWM) to
> >make LEDs seem brighter at the same power levels, but I'd like to
> >respond to this other point. Yes and no. A higher voltage WOULD make
> >the LED brighter, because it's the difference between the supply
> >voltage and the LED's forward voltage drop that determines the drop
> >across the resistor, and thus the current flow through the whole
> >shebang.
> >
> >Normally, you look at the data sheet for the LED and see that it has,
> >say, a 1.7V drop and a max current rating of 50mA. So maybe you knock
> >off 5mA to keep them living as long as possible and end up with 45mA.
> >Now supposing you have an "ideal" main bus voltage of 13.8V. That
> >means you're dropping 12.1V across the resistor. E = I * R, so 12.1V
> >= 0.045 * R. Solving for R, you get a resistance of about 269 ohms.
> >Interestingly enough, you can find 270 ohm resistors fairly readily
> >(red purple brown), so that makes a good size.
> >
> >[ I didn't mean for that explanation to patronize anybody, but it's
> >been a while since I last saw it mentioned, and it's sort of a
> >regular question so I figured I'd make a round of it for the benefit
> >of the lurkers. Bob, maybe you should make a FAQ? =) ]
> >
> >I think Bob's point was that even the biggest LEDs (and these are
> >monsters, please note) only have a 4V drop, so there's still plenty
> >of room to calculate decent limiting resistors for this (200 ohms
> >gives you roughly 50mA here, for instance). So it's a puzzle as to
> >why somebody would need to boost the voltage. Normally, all that
> >matters is that you're a certain amount above the forward voltage
> >drop of the diode.
> >
> >May I take a guess? Betcha these aren't for LEDs. Switch mode
> >regulators are quite similar to the inverters used to power EL light
> >strips, and I've seen a few mentions of those mentioned recently.
> >They require AC to excite them, usually at anywhere from 100-400
> >volts, so it's definitely a "step up" application. Also, I looked at
> >RST's site, at Jim Weir's articles, and it looks like his "mother of
> >all lamp dimmers" was designed for lamps, not LEDs (although it could
> >certainly handle both, to an extent).
> >
> >There are some advantages to both designs, but gosh, look at all the
> >parts. =) With LEDs drawing as little power as they do, it's probably
> >overkill. (That's a hypocritical statement for anybody who's seen my
> >glass cockpit design, but what the hey. )
> >
> >Regards,
> >Chad
> >
> >
> >
> >
>
>
> advertising on the Matronics Forums.
> ====
>
>
>
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>
>Why do contactors normally have one side labelled to the battery and the
>other to the load? They would appear to be a symmetrical device from the
>internal diagram in Bob's book.
some but not all contactors have one side of coil connected
internally to the BAT terminal. Often, a manufacturer uses
the same shell for all versions of the contactor and one of
the fat terminals gets marked BAT even tho it's really significant
for only part of the product line.
>The reason for the question is that I am wiring up the firewall of an RV9a
>and am using basically diags Z9 and Z24 (to control an internally regulated
>alternator). Placement of the contactor to kill the supply from the
>alternator means the wiring would be simpler if the device was wired
>'backwards'. In fact the current will also flow through it backwards in that
>if a contactor is normally handling current flowing from a battery to
>devices this contactor will be handling current flowing from an alternator
>to a battery.
If you're using a 4-terminal device, you can ignore any
marking suggesting one of the fat terminals goes to
BAT.
>The specific units concerned are the VANS Master Relay and the VANS ND 60
>amp alternator.
As I recall, Van's master relay is a 3-terminal device with one
coil lead attached to BAT. This contactor can't be used for
alternator disconnect, you need a 4-terminal device like
the S701-1 offered by B&C at:
http://www.bandc.biz/S701-1.html
and others.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Bob ... can you remind me why there are so many diodes on the various
>contactors? I'm building the 'all electric' airplane and don't really know
>why they are there.
>
>Regards,
>
>David
See http://www.aeroelectric.com/articles/spikecatcher.pdf
The S701-1 contactor from B&C is fitted with a single spike
catcher as shown at:
http://www.bandc.biz/S701-1.html
The S701-2 contactor is for crossfeed service and needs
two additional diodes for steering power from either hot
bus to the close the contactor. Hence it has three total as
seen at:
http://www.bandc.biz/S701-2.html
Bob . . .
________________________________________________________________________________
| From: | caspainhower(at)aep.com |
10/22/2003 08:01:35 PM
If you can get by with a limited # of light levels, an option is to have
multiple strings of LEDS that can be switched on separately to provide
different levels of illumination. It would be fairly easy to use op amps
to drive them and use a potentiometer to vary the voltage to the op amp
inputs. A small mechanical ganged switch would probably do the same
thing. A simpler arrangement and built in redundancy.
Craig S.
601 XL
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________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Microair 706 and Audio Iso Amp |
>Comments/Questions: I have built your Audio Iso Amp and installed with a
>Microair 760.
>On initial power-up, the only sound from the audio was an exremely
>"clipped" output. Fearing a major error, I unplugged the Amp and
>jumpered out the audio output from the radio to the audio out pins
>on the Amp harness d-dub (to bypass the Amp) and the radio worked normally
>for about 10 brief test sessions. Then the radio began behaving
>badly- activation of any switch on the radio executes a channel flip-
>flop instead of a normal function. I contacted Microair and they suspect
>a bad processor and are sending a replacement. Three questions please:
>1. Could an error on the Iso Amp damage the radio?
Not likely especially if you put it together with one of our
etched circuit boards.
>2. Is there a way to test the Amp for errors? If you can do this I would
>gladly make appropriate compensation. I believe it to be properly built,
>but did have to correct the pin assignments from what the drawing shows
>(I contacted you regarding this when I assembled the amp)
You can send it to me and I'll test it.
>3. Regarding the recent A-list discussion on dimmers- I built and
>installed a
>PWM dimmer from a kit to control my panel LEDs (almost 1.5 amps worth) I
>do not
>know what frequency it operates at, but works well and did not seem to inject
>noise into the audio while it WAS working- could this perhaps have
>affected the
>radio processor somehow?
Don't think so.
>Sorry to take up so much of your time, but the dragon is winning here...
Awww . . . he's just an especially feisty one . . . they can
all be whipped . . .
Is Microair sending you an exchange radio?
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Updated instructions for Audio Iso Amp |
I've combed out some errors and added a note (14) to
point out connector pin variations depending on how
the connector is mounted. Download:
http://www.aeroelectric.com/Catalog/AEC/9009/9009-700D.pdf
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| From: | "Jon Finley" <jon(at)finleyweb.net> |
| Subject: | Fuel Pump Popping OV CB |
Hi Bob,
I discussed this problem with you at the Field of Dreams fly-in in
Sullivan, MO a few weeks back. Now that we're not standing on the
tarmac, could you restate your suggestion?
The situation is this: I have a Subaru EJ-22 Legacy engine with fuel
injection. I have most everything wired up per your book. The problem
is that the Alternator circuit breaker pops (OV crowbar installed) when
I switch OFF the auxiliary fuel pressure pump. I temporarily hooked up
a digital meter and "caused" the problem a few times but nothing helpful
was picked up (not surprisingly).
I believe your suggestion was to install a TVS between the fuel pump and
it's switch, correct? It seems like you mentioned a capacitor, does
this ring a bell?
Thanks for all your help!
Jon Finley
N90MG Q2 - Subaru EJ-22 DD - 461 Hrs. TT
Apple Valley, Minnesota
http://www.FinleyWeb.net/default.asp?id=96
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Watsonville Seminar Nov 8/9 |
The Watsonville program is a go. Dee and I will be hauling
out of ICT Friday morning of the 7th and hope to see a bunch
of you there!
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
________________________________________________________________________________
| Subject: | Re: Updated instructions for Audio Iso Amp |
Bob, I have a Garmin GMA340 audio panel, and I have installed some mini
earphone jacks that go to its music input. Problem is with portable tape or
CD players, their output level is far short of what's needed to hear them in
the headphones. Garmin has a fix that provides 10dB gain, but that doesn't
seem to me like it will be enough, so I don't want to start removing surface
mount resistors to do it. What would be simplest would be to add a stereo
audio amplifier between my panel jacks and the Garmin music input.
I saw this post on an audio isolation amplifier, and was wondering if this
is what I need. Or if not, has there been a design (or a simple box I can
buy) discussed before?
Thanks.
Jim Oberst
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: AeroElectric-List: Updated instructions for Audio Iso Amp
>
> I've combed out some errors and added a note (14) to
> point out connector pin variations depending on how
> the connector is mounted. Download:
>
> http://www.aeroelectric.com/Catalog/AEC/9009/9009-700D.pdf
>
> Bob . . .
>
> --------------------------------------------
> ( Knowing about a thing is different than )
> ( understanding it. One can know a lot )
> ( and still understand nothing. )
> ( C.F. Kettering )
> --------------------------------------------
>
>
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Fuel Pump Popping OV CB |
>
>Hi Bob,
>
>I discussed this problem with you at the Field of Dreams fly-in in
>Sullivan, MO a few weeks back. Now that we're not standing on the
>tarmac, could you restate your suggestion?
>
>The situation is this: I have a Subaru EJ-22 Legacy engine with fuel
>injection. I have most everything wired up per your book. The problem
>is that the Alternator circuit breaker pops (OV crowbar installed) when
>I switch OFF the auxiliary fuel pressure pump. I temporarily hooked up
>a digital meter and "caused" the problem a few times but nothing helpful
>was picked up (not surprisingly).
>
>I believe your suggestion was to install a TVS between the fuel pump and
>it's switch, correct? It seems like you mentioned a capacitor, does
>this ring a bell?
>
>Thanks for all your help!
Send me your mailing address and I'll ship you
some parts to try.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Updated instructions for Audio Iso Amp |
><joberst@cox-internet.com>
>
>Bob, I have a Garmin GMA340 audio panel, and I have installed some mini
>earphone jacks that go to its music input. Problem is with portable tape or
>CD players, their output level is far short of what's needed to hear them in
>the headphones. Garmin has a fix that provides 10dB gain, but that doesn't
>seem to me like it will be enough, so I don't want to start removing surface
>mount resistors to do it. What would be simplest would be to add a stereo
>audio amplifier between my panel jacks and the Garmin music input.
>
>I saw this post on an audio isolation amplifier, and was wondering if this
>is what I need. Or if not, has there been a design (or a simple box I can
>buy) discussed before?
The audio iso amp as configured has a voltage gain of about 1.0
but it could be higher. Is the music input mono or stereo? Do you
have a specification for the input sensitivity of this port? In the
automotive world, aux inputs are on the order of 500 mv rms (1.5v pk-pk)
which is in the same ballpark as headset outputs. I'm a bit mystified
as to why you're having problems.
Bob . . .
________________________________________________________________________________
| From: | Pete Waters <pedroagua(at)yahoo.com> |
| Subject: | Alternator Noise in Headset - Epilogue? |
Bob,
If the weather cooperates, I'll even bring the RV-4 we've been discussing on
the Aerolelectric list.
BTW, I replaced the voltage regulator I had with an automotive one (a Transpo),
and I no longer hear the Morse Code-like noise. The new VR cost me about
$20. I also took the alternator and old regulator out of the airplane to an automotive
alternator shop. They found nothing wrong with either, but at least
in the process I learned that the alternator, which is still in great shape,
is a 35 A Nippondenso model off a mid-70's Honda. The old voltage regulator
is probably of the same vintage, but is completely unmarked and therefore a complete
mystery part. For $20 it was worth it for me to just replace the VR so
that I could write a model and part number on the massive airplane configuration
spreadsheet I'm gradually constructing. I also replace the automotive voltmeter
that came in the airplane with an Electronics Instruments VA-1A volt/ammeter
so I could have an ammeter in the plane to diagnose any future electrical
issues. Right off, I learned that, with both lan
ding
lights off, I pull about 13 A with everything else on; with both landing lights
on, I pull 31 A (off a 35A alternator) and get a flickering discharge light
on the ammeter. So, I clearly need to either (a) go to lower-wattage landing
lights, or (b) disconnect one of them, (c) live with it for the short period
on final when everything is one, or (d) get a higher-output alternator. I'll
probably go for (a) in the short term and (d) at the next annual.
I'm not sure if the headset noise won't return, but at least I'm learning how
this plane is wired.
I'll copy this to the Aeroelectric list also to share it with the bubbas.
Thanks for all the help,
Pete Waters
See you in Watsonville, by plane if VFR, by car if not
---------------------------------
________________________________________________________________________________
| Subject: | Re: Updated instructions for Audio Iso Amp |
| From: | caspainhower(at)aep.com |
10/23/2003 12:39:44 AM
>Problem is with portable tape or
>CD players, their output level is far short of what's needed to hear them
in
>the headphones.
This might seem obvious but make sure you use the headphone output and not
the line out. I have the same problem I hook up to the line output of the
portable CD player in my Skyhawk. It take about 30 - 50% volumn adjustment
to achieve a comfortable level in the headsets.
Craig S.
This e-mail message and all attachments transmitted with it from the
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use of the intended recipient(s) and may contain confidential and
privileged information. Any unauthorized review, use, disclosure or
distribution is prohibited. If you are not the intended recipient, please
contact the sender by reply e-mail and destroy all copies of the original
message.
________________________________________________________________________________
| From: | Vince Ackerman <vack(at)mac.com> |
Bob,
Do you know the lowest voltage required to hold the coil closed (on B&C
Contactor)? I don't have a variable power supply or I'd check it myself.
Thanks
Vince
________________________________________________________________________________
| Subject: | Re: Substitute for Shoo Goo |
Bob,
Thanks for your answer and your offer.
Before you get into too much trouble I'll try and make sure we really don't
have a suitable substitute at hand.
Had a peek at their website. Rally amazing stuff indeed. I gather it is a
rubber base sealant-adhesive or something.
Thank you,
Gilles
> No, hot melts are a whole other attachment technology. The
> more generic, industrial equivalent of Shoe Goo is E-6000
> offered by Eclectic Products (also makes Shoe Goo). Check with
> hardware and craft stores. If push comes to shove, I could
> get some and send it to you. This is a unique product with
> extra-ordinary capabilities. There are undoubtedly other products
> with similar capabilities but I've not researched any.
>
>
> Bob . . .
>
>
________________________________________________________________________________
| From: | Charles Brame <charleyb(at)earthlink.net> |
| Subject: | Contactor Question |
I have a Van's three terminal Master Contactor. I have two fat wires and
a diode attached to the BAT terminal. I need to connect a back up
alternator lead to the same terminal, but there ain't no more room. Is
there an easy solution other than going to a four terminal contactor?
Charlie Brame
RV-6A N11CB
San Antonio
________________________________________________________________________________
| Subject: | Garmin GMA340 music volume was: Updated instructions |
for Audio Iso Amp
| From: | royt.or(at)netzero.com |
Jim, Bob,
I'm using the equivalent of a boostaroo (see http://www.boostaroo.com/) that I got from Radio Shack for about $20.00. This is ~$30.00 on the boostaroo web page. (Currently, I can not find this on the Radio Shack web page.)
This works well for using a portable CD/MP3 player with the Garmin GMA340 in my
plane. I plan to try the Garmin update in the future.
Regards,
Roy
CH601HDS, Rotax 912S, All electric panel. 130 hours since first flight on 5/12/03
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Substitute for Shoo Goo |
><Gilles.Thesee@ac-grenoble.fr>
>
>Bob,
>
>Thanks for your answer and your offer.
>Before you get into too much trouble I'll try and make sure we really don't
>have a suitable substitute at hand.
>Had a peek at their website. Rally amazing stuff indeed. I gather it is a
>rubber base sealant-adhesive or something.
I think it's a polyurethane or close cousin. It's tough as
a boot when cured (hence characteristics adequate for gluing
one's sneakers back together). Really more of a plastic than
a rubber. It would be no big deal to ship you a tube if
needs be. I can get it in a hobby shop two blocks from
my house.
I note that Eclectic's website speaks of retail outlets
in US, Canada, Mexico and Asia . . . hmmm . . . might
have to send you some. I'll check with Todd at B&C
to see if they're interested in stocking it.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
>
>Bob,
>
>Do you know the lowest voltage required to hold the coil closed (on B&C
>Contactor)? I don't have a variable power supply or I'd check it myself.
>
>Thanks
>
>Vince
At room temperature, the one I have picks up at 6 and drops
out at 4 volts.
Bob . . .
________________________________________________________________________________
| From: | "Dan Checkoway" <dan(at)rvproject.com> |
| Subject: | Re: Updated instructions for Audio Iso Amp |
Jim,
I can tell you that the optional gain does work very well on the GMA-340.
It boosts it more than you might think. I went and installed a little
toggle switch on my panel to control the boost on/off. You might want to
give it a shot and try it out before going with a more complicated solution.
Just my 2 cents!
)_( Dan
RV-7 N714D
http://www.rvproject.com
----- Original Message -----
From: "J. Oberst" <joberst@cox-internet.com>
Subject: Re: AeroElectric-List: Updated instructions for Audio Iso Amp
<joberst@cox-internet.com>
>
> Bob, I have a Garmin GMA340 audio panel, and I have installed some mini
> earphone jacks that go to its music input. Problem is with portable tape
or
> CD players, their output level is far short of what's needed to hear them
in
> the headphones. Garmin has a fix that provides 10dB gain, but that
doesn't
> seem to me like it will be enough, so I don't want to start removing
surface
> mount resistors to do it. What would be simplest would be to add a stereo
> audio amplifier between my panel jacks and the Garmin music input.
>
> I saw this post on an audio isolation amplifier, and was wondering if this
> is what I need. Or if not, has there been a design (or a simple box I can
> buy) discussed before?
>
> Thanks.
>
> Jim Oberst
>
> ----- Original Message -----
> From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
> To:
> Subject: AeroElectric-List: Updated instructions for Audio Iso Amp
>
>
>
> >
> > I've combed out some errors and added a note (14) to
> > point out connector pin variations depending on how
> > the connector is mounted. Download:
> >
> > http://www.aeroelectric.com/Catalog/AEC/9009/9009-700D.pdf
> >
> > Bob . . .
> >
> > --------------------------------------------
> > ( Knowing about a thing is different than )
> > ( understanding it. One can know a lot )
> > ( and still understand nothing. )
> > ( C.F. Kettering )
> > --------------------------------------------
> >
> >
>
>
________________________________________________________________________________
| From: | "Joseph Kearns, DO,MPH,FACOEM" <Kearns(at)pol.net> |
| Subject: | Re: Wire Selection |
Valued contributors.
Does anyone have an excel spreadsheet that will consider temp, length,
current, bundled, ... and will give the suggested gage according to the
AC43-13? Thanks.
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Contactor Question |
>
>
>I have a Van's three terminal Master Contactor. I have two fat wires and
>a diode attached to the BAT terminal. I need to connect a back up
>alternator lead to the same terminal, but there ain't no more room. Is
>there an easy solution other than going to a four terminal contactor?
Hmmm . . . the Cole-Hersee contactors have a fat wire stud
length about 0.1" shorter than the RBM/Stancore parts from
B&C . . . it can present a problem with terminal stacking.
Do you have a battery bus? If so, you can tie the aux alternator
to a fuse slot on the battery bus and eliminate the fusible link.
I'd go for a 15A fuse in off the battery bus.
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | Re: Alternator Noise in Headset - Epilogue? |
>
>Bob,
>
> If the weather cooperates, I'll even bring the RV-4 we've been
> discussing on the Aerolelectric list.
great!
> BTW, I replaced the voltage regulator I had with an automotive one (a
> Transpo), and I no longer hear the Morse Code-like noise. The new VR
> cost me about $20. I also took the alternator and old regulator out of
> the airplane to an automotive alternator shop. They found nothing wrong
> with either, but at least in the process I learned that the alternator,
> which is still in great shape, is a 35 A Nippondenso model off a mid-70's
> Honda. The old voltage regulator is probably of the same vintage, but is
> completely unmarked and therefore a complete mystery part.
Good detective work. I've run into a whistling regulator
a couple of times that I can recall. My design for the B&C LR-1 and
LR-2 regulators would go into oscillation at an inaudible
radio frequency that upset ADF and Loran receivers when driving
a long regulator-to-field wire in canard pushers. I think
I recall talking with two different builders about adding
a capacitor inside the regulator to stop the problem. We
got it right with the LR-3 series regulators later.
> For $20 it was worth it for me to just replace the VR so that I could
> write a model and part number on the massive airplane configuration
> spreadsheet I'm gradually constructing.
Sure. The generic "ford" regulators are a good example
of a $5 to $20 regulator that gives good service.
> I also replace the automotive voltmeter that came in the airplane with
> an Electronics Instruments VA-1A volt/ammeter so I could have an ammeter
> in the plane to diagnose any future electrical issues. Right off, I
> learned that, with both landing
> lights off, I pull about 13 A with everything else on; with both
> landing lights on, I pull 31 A (off a 35A alternator) and get a
> flickering discharge light on the ammeter.
Hmmm . . . fat rascals aren't they?
> So, I clearly need to either (a) go to lower-wattage landing lights, or
> (b) disconnect one of them,
or put them on separate switches so you have one or both but
always an independent spare should one turn belly up.
> (c) live with it for the short period on final when everything is one,
this isn't a sin either . . . how about two switches with a wigwag
system. You can turn on both lights in the last few seconds before
flare and keep total lighting loads down to 9A before this time.
> or (d) get a higher-output alternator.
I think what you have will do just fine.
> I'll probably go for (a) in the short term and (d) at the next annual.
> I'm not sure if the headset noise won't return, but at least I'm
> learning how this plane is wired.
> I'll copy this to the Aeroelectric list also to share it with the bubbas.
I appreciate that. See you in Watsonville!
Bob . . .
________________________________________________________________________________
| From: | "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> |
| Subject: | An electrical system for my homebuilt |
>Bob,
>
>
>In France, a small minority of people have the "Legion d'honneur". A
>minority in this minority really deserves it. I believe that if you live
>in France you would deserve it!
>I build a two-seats aircraft in composite (carbon epoxy). It is a MCR 01
>SPORTSTER known in US under the name of LAFAYETTE. It is powered with a
>ROTAX 912 and gently cruise at 140 Kts.
>
>I discovered your Web site thanks to (excellent!) friend of mine. I do not
>put myself any more a question, I have the answers!!!!! It is a true gold
>mine and I think that it is necessary to be right and don't forget the minor!!
>
>I want to buy at B&C all which I need to carry out my wiring and first of
>all, THE BOOK !!.
Thank you for the kind words . . .
>As the Atlantic Ocean separates us, I have many questions to ask to you in
>order to avoid making errors by writing this order.
> * Which is the wire is necessary to employ for the control circuits?
> The electric considerations would allow very fine gauges: AWG 34 for the
> relays of engine control of flaps (200 ma) by ex. But of the mechanical
> considerations (brittleness) and especially the possibility of crimping
> seems to limit the choice to AWG 22. Is it correct?
Correct. We use some 24AWG wire in harnesses on Premier at Raytheon
with a mixed bag of reaction from folks on the line. Personally,
22AWG is the smallest wire I would use in the airframe. Some folks
have wired with 20AWG as the smallest . . . it fits into all but a few
avionics connectors and handles currents up to 7A which covers the
majority of installed systems. 20AWG Tefzel is no heavier than 22AWG
nylon over PVC of yesteryear . . . and in any case . . . would probably
add less than a pound of empty weight to a simple airplane.
> * Is your S704-1 relay a good choice for the engine control of flaps
> (10 A) and trim (5 A). I will use 2 relays in "H bridge" for each one.
It's certainly BIG enough and one could consider smaller relays. I like
this particular product for ease of use. It's easy to mount and wire.
> * Do you think that it is possible (and desirable) to entirely carry
> out a full disconnectable instrument panel thanks to D-Sub connectors.
If you use any connector for this purpose, a D-sub is hard to beat.
Consider also building your airframe to panel wire harness with
perhaps 1' of slack in it so that you can dismount the panel and
lay it aside without disconnecting it. Either way should serve
you well as long as the connector quality is good. Machined pin
d-subs would be my connector of choice.
> * When you are read, one could believe that the "buses bar" are
> reserved for the "breakers". I will use fuses (of course !) and in
> particular Fuseholder (20 position). Which is the good method to
> distribute the PLUS to all fuses?
A bus bar is built into the fuse holder. A single fat screw visable
centered on one end is the commom (+) supply for all of the fuses
in the holder.
> * Logically, it would be necessary to protect the wiring located
> between the battery and the Fuseholder with a principal fuse located
> close to the battery. Does one have to do it?
You don't need to do this. These wires are classically BIG. Further,
there are only a few and easy to install with extra care to preclude
mechanical damage that might ground the wire. When you get the book,
you will note there are no special provisions for protecting fat
wires in the airplane. All fat-wires in certified single engine
airplanes are treated the same way here in the US
> * I do not see on B&C Web site the in line fuse (JJN/JJS Serie
> cartridge fuse) allowing to protect the alternator which you describe in
> your article "Circuit_protection.pdf".
The JJN/JJS series fuses are offered only for spares for folks who
installed them per recommendations of some years back. B&C uses the
ANL series devices in their kits for certified alternators so it
made more sense to convert to the ANL series for all high current
circuit protection.
> * In France, the MICROAIR VHF has been approved only for one month
> (!). It interests me much, because beyond his good service/price ratio,
> it is the least long of the market and in my case, they is very
> advantageous. Do you have good opinions on this radio?
I have sold about two dozen. Out of these, I am aware
of only one that needed to be returned for service. This
is a relatively new product and I expect some early
learning glitches . . . I think their radios are good
value and so far, their willingness to fix misbehaving
radios is quite good. I would probably put Microair radios
in the panel if I were building an airplane.
> * I saw that you provide a harness for this radio. Which are its
> advantages compared to that which provided MICROAIR? It is not on the B
I don't know the details of their harness but I suspect it's
not much different than the one we offered. I'm out of stock
on those harnesses for now put plan to do a batch of both 760VHF
and T2000 harnesses and put them back up on my website. B&C
doesn't plan to offer them but I'll have them again soon.
> * Which is the best place to install a "spike catching diode", at the
> boundaries of the contact or the boundaries of the coil?
On the coil.
See http://www.aeroelectric.com/articles/spikecatcher.pdf
> * Which is the good protection device for the engine of the starter?
> The question of the protection of the cable between the battery and the
> relay also arises (?).
These wires are very rarely a problem and are not protected.
The wiring diagrams in the book will illustrate placement
and numbers of recommended circuit protection.
>
>Thank you for your answers.
You are most welcome. Good luck on your project.
I will invite you to join us on the AeroElectric List
to continue this and similar discussions. It's useful to
share the information with as many folks as possible.
A further benefit can be realized with membership on
the list. There are lots of technically capable folks
on the list who can offer suggestions too. You can
join at . . .
http://www.matronics.com/subscribe/
Well considered and technically elegant answers to
all of your questions are waiting for you there. Also,
check out the downloadable materials at
http://www.aeroelectric.com
Thanks!
Bob . . .
|---------------------------------------------------|
| A lie can travel half way around the world while |
| the truth is till putting on its shoes . . . |
| -Mark Twain- |
|---------------------------------------------------|
________________________________________________________________________________
October 13, 2003 - October 23, 2003
AeroElectric-Archive.digest.vol-cn