Today's Message Index:
----------------------
1. 06:40 AM - Alternator Systems (Mike Lehman)
2. 07:31 AM - headphone sockets (Fergus Kyle)
3. 07:47 AM - Re: Placing headset jacks (Paul Messinger)
4. 08:05 AM - Resetting C/Bs (Fergus Kyle)
5. 08:16 AM - Re: Alternator Systems (Paul Messinger)
6. 09:32 AM - Resetting C/Bs (David Swartzendruber)
7. 10:44 AM - Firewall penetration (David Carter)
8. 11:10 AM - Re: Alternator Systems (Robert L. Nuckolls, III)
9. 11:19 AM - Re: Resetting C/Bs (Paul Messinger)
10. 02:01 PM - Re: Resetting C/Bs (Robert L. Nuckolls, III)
11. 02:07 PM - Re: Resetting C/Bs (Robert L. Nuckolls, III)
12. 03:19 PM - Radio Noise (cecilth@juno.com)
13. 03:19 PM - Re: Resetting C/Bs (David Swartzendruber)
14. 03:28 PM - Re: Resetting C/Bs (Tom FRIEDLAND)
15. 03:58 PM - Re: Firewall penetration (Ron)
16. 04:11 PM - Re: Alternator Systems (Benford2@aol.com)
17. 05:45 PM - Re: Firewall penetration (Julia)
18. 05:59 PM - Re: Firewall penetration (Julia)
19. 10:55 PM - question on alternators/controllers (Aucountry@aol.com)
Message 1
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| Subject: | Alternator Systems |
--> AeroElectric-List message posted by: "Mike Lehman" <LehmansMtl@netzero.com>
Paul Messinger,
I've just received a delivery fail notice for this reply (edited) sent to you privately
(because the idea was posted previously) about 5 days ago:-
Paul,
I'd like to extend your analysis 1 step.
We've got an external voltage regulator powered via a 5 amp field supply breaker.
However, virtually all light aircraft then power the field breaker from the
battery side of the 'B' lead fuse/breaker (typically 40 to 60 amps rating).
If this main breaker/fuse opens, the VR senses low voltage and maximizes alternator
field current in the impossible attempt to restore 13.8 to 14.5 volts on
the disconnected buss. The result is 100+ volts at the alternator B terminal
and sometimes severe alternator damage involving the faults mentioned. In my
opinion, the field supply breaker should be powered from the alternator side
of the main breaker.
Regards,
Mike
Message 2
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| Subject: | headphone sockets |
--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
">Hello Mark, After 44 years plus of plugging headsets plugs into a wide
>variety of locations I came to the conclusion that the best location for
the
>pilot's headset jacks (in a side by side seating arrangement) was behind
the
>copilots seat back and the best location for the copilots headset jacks was
>behind the pilots seatback. In sight and always reachable even when
strapped
>in. No plugs to bump with your knee and no cords lying across your lap.
Agreed. I was going to suggest above, behind and outboard of the
seat. I put some intercom systems in C-150s and moved the
mic-headset jacks to small boxes behind the seats. Cords were
always out of the way. Bob . . . "
Cheers,
On the topic of 'where do I put the headphone holes?', I thought
back to the fighter cockpits of yore (where space CAN be a problem, and hard
treatment also) in considering where mine ought to go.
In one, the plugs entered a socket pair on the wall at the right
knee. One leaned forward on entry and plugged in - the lines draped down to
the ankle and either inside or outside the belts. Damage to the leads was
minimal but was result of unsnagging on occasion.
In another, the sets were plugged in behind the head (plug in
the helmet, set it aside, then enter ). This produced a twofoot loop to
permit reaching forward, but was innocuous enough except for the entry need.
The third was the simplest - it plugged in at the hip on the
bump seat. Easy to attach, easy to avoid (came up the back of one shoulder),
minimum loop because the required length stayed constant, and if you gotta
go, the headset required no unplugging. This site is mitigated somewhat by
having to be protected against dust etc.
The number of aviators is legion, whose necks were stretched by
helmets plugged into departed aircraft.
Might be worth considering -
Ferg
Europa A064
Message 3
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| Subject: | Re: Placing headset jacks |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@tenforward.com>
I would put them so the cords are on the inside between the pilots but
otherwise agree with you both. My logic is if you need to exit in a rush
there are no cords between you and the door.
Paul
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Placing headset jacks
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 12:15 PM 3/28/2003 -0500, you wrote:
> >--> AeroElectric-List message posted by: BAKEROCB@aol.com
> >
> >AeroElectric-List message posted by: Mark Phillips <ripsteel@edge.net> on
> >placing headset jacks
> >
> ><<.....skip....Now if I could just decide where to drill these six little
> >holes!
> > ....skip...... Mark Phillips >>
> >
> >3/28/2003
> >
> >Hello Mark, After 44 years plus of plugging headsets plugs into a wide
> >variety of locations I came to the conclusion that the best location for
the
> >pilot's headset jacks (in a side by side seating arrangement) was behind
the
> >copilots seat back and the best location for the copilots headset jacks
was
> >behind the pilots seatback. In sight and always reachable even when
strapped
> >in. No plugs to bump with your knee and no cords lying across your lap.
>
> Agreed. I was going to suggest above, behind and outboard of the
> seat. I put some intercom systems in C-150s and moved the
> mic-headset jacks to small boxes behind the seats. Cords were
> always out of the way.
>
> Bob . . .
>
>
Message 4
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--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
"Bob is clearly right on with this one. Ricky Nelson and several others were
KILLED by a flight crew person repeatedly resetting a circuit breaker on a
DC3 till the heater went up in smoke. !!!!!!!"
Cheers,
See also: Air Canada DC-9 fire at Pittsburgh - and it
doesn't take aircrew to screw up - too many C/Bs in the cabin make that
possible. Wonder where the C/B for cabin entertainment on Swissair's FLt 111
was?
....and, bibliography on Kapton wiring may also provide
info!
Ferg
Message 5
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| Subject: | Re: Alternator Systems |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@tenforward.com>
Thanks, Some of us who live in the outskirts have problems from time to time
with the local ISP. Also lost mail etc. Not to mention no reasonable cost
hispeed access. Fast here is 26K.
While this should not be a design used by experimentals ( or any one ) I
agree with your point.
Thanks for the extra effort to contact me.
Paul
----- Original Message -----
From: "Mike Lehman" <LehmansMtl@netzero.com>
Subject: AeroElectric-List: Alternator Systems
> --> AeroElectric-List message posted by: "Mike Lehman"
<LehmansMtl@netzero.com>
>
> Paul Messinger,
>
> I've just received a delivery fail notice for this reply (edited) sent to
you privately (because the idea was posted previously) about 5 days ago:-
>
> Paul,
>
> I'd like to extend your analysis 1 step.
>
> We've got an external voltage regulator powered via a 5 amp field supply
breaker. However, virtually all light aircraft then power the field breaker
from the battery side of the 'B' lead fuse/breaker (typically 40 to 60 amps
rating). If this main breaker/fuse opens, the VR senses low voltage and
maximizes alternator field current in the impossible attempt to restore 13.8
to 14.5 volts on the disconnected buss. The result is 100+ volts at the
alternator B terminal and sometimes severe alternator damage involving the
faults mentioned. In my opinion, the field supply breaker should be powered
from the alternator side of the main breaker.
>
> Regards,
> Mike
>
>
Message 6
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--> AeroElectric-List message posted by: "David Swartzendruber" <dswartzendruber@earthlink.net>
I'm involved in a discussion concerning resettable circuit protection verses
non-resettable in certified aircraft. Any resources you guys can recommend
would be appreciated.
One of the challenges with the non-resettable argument for certified
aircraft is that after certification, an aircraft is hard to change. If it
gets through certification with a system that has nuisance tripping of the
circuit protection device, the owner is stuck with it. Therefore you have
the argument that you need to be able to reset the circuit breaker because
you can't fix the problem.
The other argument I'm facing is that even though there may be a plan B when
plan A fails, plan A is more convenient. Therefore, if we can use plan A
even a few more times by simply resetting the circuit breaker, it's better
for the pilot.
What I would like to determine is whether there is enough of a safety hazard
to resetting circuit breakers to offset the need to reset a poorly designed
system that can't be changed.
Dave in Wichita
Message 7
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| Subject: | Firewall penetration |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
For Ron Triano, ref your e-mail to the list Sat March 1st,
I looked at stainless steel grab bars at Lowe's last night - $18 to $20 depending
on length, 1 1/4" dia I think, with welded flange.
I'd rather have the 5/8 diameter that you are using. Can you tell us where you
bought it (or where we could buy it), manufacturer, part number? I can't find
any "towel racks" that have this stainless steel flange on hollow tube feature.
I suspect the 5/8 towel bar will be cheaper than the 1 1/4 dia grab bar.
David Carter
Message 8
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| Subject: | Re: Alternator Systems |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:34 AM 3/29/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Mike Lehman"
><LehmansMtl@netzero.com>
>
>Paul Messinger,
>
>I've just received a delivery fail notice for this reply (edited) sent to
>you privately (because the idea was posted previously) about 5 days ago:-
>
>Paul,
>
>I'd like to extend your analysis 1 step.
>
>We've got an external voltage regulator powered via a 5 amp field supply
>breaker. However, virtually all light aircraft then power the field
>breaker from the battery side of the 'B' lead fuse/breaker (typically 40
>to 60 amps rating). If this main breaker/fuse opens, the VR senses low
>voltage and maximizes alternator field current in the impossible attempt
>to restore 13.8 to 14.5 volts on the disconnected buss. The result is
>100+ volts at the alternator B terminal and sometimes severe alternator
>damage involving the faults mentioned. In my opinion, the field supply
>breaker should be powered from the alternator side of the main breaker.
I have seen this theory advanced before . . . and illustrated
in a number of wiring diagrams . . . some on STC'd alternator
installations for certified aircraft.
Consider that the 60A breaker on virtually ALL production
aircraft with alternators is DESIGNED to nuisance trip. I've
had it happen to me on one occasion. In this instance and
many others observed over the years, the regulator does
indeed go to full-output in an attempt to raise bus voltage.
I've never talked to the designers who choose to wire
the field supply to the alternator side of the b-lead
breaker . . . so I can only guess at their rational for
doing so. It's fairly easy to deduce the effects of
this architecture under various abnormal conditions.
If the b-lead breaker is open before the system is brought
up, the alternator never gets start-up power from the
bus and as long as the alternator is incapable of self
exciting, it will remain dormant after engine start
irrespective of switch positions.
If the b-lead breaker opens due to nuisance trip after
the system is running, then the alternator is indeed
isolated from the bus and it may continue to run self
excited but regulated.
I cannot deduce any particular benefit for wiring
the system this way. It may be that the designer
was concerned about the potential for diode failure
in the "runaway" condition that results when the
regulator looses sight of the b-lead output voltage.
Diode failure under open-circuit runaway conditions
was a key component of Paul's failure mode hypothesis
that I didn't recognize at first. Let's examine
this hypothesis:
I've heard also that typical alternator diodes are
RATED at 200 piv or thereabouts. In some components,
it may be rational to assume that the device is at
high risk of failure at 225 or even 250 volts.
Considering the fact that b-lead breakers open
routinely in certified ships and often goes unnoticed
for minutes to hours suggests that the non-regenerative
runaway (field stays at bus voltage) doesn't
produce a lot of failures. I've read many
dark-n-stormy night stories and even my
own experience has demonstrated that this
is not an automatic recipe for diode failure.
About 40 years ago, I was doing design work
in a nuclear fuel processing plant. I had
a task to look at ways to modernize some of
our GM tube radiation detectors. The GM tube
needed a relatively constant 900 volt
source for proper operation. At the suggestion
of one of the best teachers I ever had,
I explored the avalanche (breakdown) voltage
of garden variety silicon diodes. I found that
many 400 volt rated devices went into avalanche
in the 900 +/- 50V range I was looking for.
The current we subjected these devices to was
on the order of 10-20 MICROamps so the energy
dissipated was well within the physical
ability of the diode to tolerate. Here's
an example of how a diode could be usefully
operated in a mode that might otherwise prove
fatal to the device. The interesting point
of this experience was that the 400 volt
devices didn't go into potentially fatal
avalanche operation at voltages more than
TWICE the rated voltage of the device.
Of course, this is quite temperature dependent
and in no way suggests that we should count
on a run-of-the-mill alternator diode being
good for 400 volts . . . my point is that
past experience shows that these alternators
are routinely capable of sustained operation
at 8-15 times normal output voltage without
suffering diode failure.
Which brings me to the condition Paul was
considering hazardous. I agree that diode
failure (opens or shorts) and/or mechanical
shorts in windings to the core are necessary
to produce burned windings. In a 3-phase
alternator, each winding carries an average
of 1/3 total output meaning that a 60A
alternator can be wound with 20A wire. When
load sharing is upset by any of several
failures, stator windings are indeed at risk
of overload and destruction.
Never-the-less, destruction of the windings
while smelly is not very spectacular and
given their location on the engine, they
represent no risk of bringing one spiraling
out of the sky trailing black smoke and
flames.
Getting back to the idea of relocating the
field feed breaker to the alternator
side of the b-lead breaker . . . The
only benefit I can deduce for this design
is to limit the alternator's output in
case the b-lead breaker nuisance trips.
We KNOW this to be a long standing, well understood
problem with the design of most certified
ships flying . . . it seems better
to up-size the b-lead protection to ELIMINATE
the nuisance trip than to relocate field
feed point to ACCOMMODATE what amounts to
a basic design flaw.
One last failure mode: In the case of
REGENERATIVE runaway for an alternator with a
built-in regulator where we deliberately cut the
b-lead loose from the airplane, there is
certainly an increased risk of loosing diodes
compared to the simple fixed-field runaway
that occurs when the b-lead breaker opens
and the field stays at 12v.
This is a toss of the coin. We know that b-lead
output will rise quickly to levels that are
greater than fix-field levels. It seems like
the alternator design would benefit from an
internal field fuse rated at, say 5A. This is
much higher than any normal field currents but
much lower than what would be induced by a
regenerative runaway . . . the I(squared)*T
constant for the fuse is much shorter than
for 22AWG field winding wire. A regenerative
runaway event would terminate very quickly at
much less risk to the diodes.
The likelihood of ever having an ov condition
is low. Likelihood of burning stator wires is
not zero but it's low. Likelihood of a burned
wire being a hazard is extremely low. Aside
from having rotors balanced (with pulley
installed), I can think of nothing we might
do to INCREASE reliability of these inexpensive
and robust products.
I find no compelling reason to discourage anyone
from taking advantage of modern, internally
regulated alternators when fitted with a means
for containing an overvoltage event. These
alternators are demonstrably better products
than those flying most certified ships today.
Many OBAM aircraft owners have elected to run
one-wire alternators without ov protection.
The odds of a trouble free operation over the
lifetime of the airplane are very much in their
favor.
Bob . . .
Message 9
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| Subject: | Re: Resetting C/Bs |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@tenforward.com>
I have had smoke in the cockpit in certificated acft a couple of times. A
master breaker saved my butt once as it was in IFR. Turned out to be COM #2.
breaker never opened as short was current limited and hist burned internal
to radio. The other case was the same but could have continued with master
off if needed.
Had I not has a manually openable CB I am not sure how things would have
turned out. So its not just a CB but if you have one be sure you can pull it
open.
What I did was to pull the master and then each individual CB. reset master
and close others one at a time until source of smoke was found. No radio/nav
was not really an option in IFR.
However all the cases of crashes etc from having resetable CB is from the
pilots or crews lack of the first rule of flight. FLY THE AIRPLANE FIRST AND
ALWAYS.
Many pilots allow a problem to distract them and the result is usually very
bad. A simple problem crashed the afft because of pilot distraction.
Thus I feel in most cases Bob is right. Design your acft so you can keep
going with no inflight trouble shooting needed.
Paul
----- Original Message -----
From: "David Swartzendruber" <dswartzendruber@earthlink.net>
Subject: AeroElectric-List: Resetting C/Bs
> --> AeroElectric-List message posted by: "David Swartzendruber"
<dswartzendruber@earthlink.net>
>
> I'm involved in a discussion concerning resettable circuit protection
verses
> non-resettable in certified aircraft. Any resources you guys can
recommend
> would be appreciated.
>
> One of the challenges with the non-resettable argument for certified
> aircraft is that after certification, an aircraft is hard to change. If
it
> gets through certification with a system that has nuisance tripping of the
> circuit protection device, the owner is stuck with it. Therefore you have
> the argument that you need to be able to reset the circuit breaker because
> you can't fix the problem.
>
> The other argument I'm facing is that even though there may be a plan B
when
> plan A fails, plan A is more convenient. Therefore, if we can use plan A
> even a few more times by simply resetting the circuit breaker, it's better
> for the pilot.
>
> What I would like to determine is whether there is enough of a safety
hazard
> to resetting circuit breakers to offset the need to reset a poorly
designed
> system that can't be changed.
>
> Dave in Wichita
>
>
Message 10
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| Subject: | Re: Resetting C/Bs |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:37 AM 3/29/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "David Swartzendruber"
><dswartzendruber@earthlink.net>
>
>I'm involved in a discussion concerning resettable circuit protection verses
>non-resettable in certified aircraft. Any resources you guys can recommend
>would be appreciated.
>
>One of the challenges with the non-resettable argument for certified
>aircraft is that after certification, an aircraft is hard to change. If it
>gets through certification with a system that has nuisance tripping of the
>circuit protection device, the owner is stuck with it. Therefore you have
>the argument that you need to be able to reset the circuit breaker because
>you can't fix the problem.
>
>The other argument I'm facing is that even though there may be a plan B when
>plan A fails, plan A is more convenient. Therefore, if we can use plan A
>even a few more times by simply resetting the circuit breaker, it's better
>for the pilot.
>
>What I would like to determine is whether there is enough of a safety hazard
>to resetting circuit breakers to offset the need to reset a poorly designed
>system that can't be changed.
Why would a poorly designed system have to go to production?
Surely we've got plenty of lessons learned from the past 5 decades
of aircraft production. It's hard to beat good critical design review
from a cadre of folks who understand the goals AND the
history of where we've come from. In the final analysis,
when in doubt, make it the next size bigger. There's nothing
that prohibits you from piping power to a product on bigger
wires than might otherwise be assumed adequate. Knowing the
characteristics of the load is useful too . . . "Oh yeah,
when it goes into the self cleaning mode, current draw
is 50% above operating mode . . . we recommend you don't
punch that button while airborne . . ." The questions
that bite later are the ones not asked going in.
No matter how convenient Plan A, there will always
be a whole lot more failure modes that DON'T pop
the breaker than the ones which DO pop the breaker.
Likelihood of "saving the day" or even improving
levels of comfort for having a breaker to punch
is very low.
Bob . . .
Message 11
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| Subject: | Re: Resetting C/Bs |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:19 AM 3/29/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger"
><paulm@tenforward.com>
>
>I have had smoke in the cockpit in certificated acft a couple of times. A
>master breaker saved my butt once as it was in IFR.
what's a "master breaker"?
> Turned out to be COM #2.
>breaker never opened as short was current limited and hist burned internal
>to radio. The other case was the same but could have continued with master
>off if needed.
>Had I not has a manually openable CB I am not sure how things would have
>turned out. So its not just a CB but if you have one be sure you can pull it
>open.
I'm surprised that the on/off switch for a radio didn't offer
a disconnect for everything powered within the radio.
>What I did was to pull the master and then each individual CB. reset master
>and close others one at a time until source of smoke was found. No radio/nav
>was not really an option in IFR.
>
>However all the cases of crashes etc from having resetable CB is from the
>pilots or crews lack of the first rule of flight. FLY THE AIRPLANE FIRST AND
>ALWAYS.
>
>Many pilots allow a problem to distract them and the result is usually very
>bad. A simple problem crashed the acft because of pilot distraction.
>
>Thus I feel in most cases Bob is right. Design your acft so you can keep
>going with no inflight trouble shooting needed.
I think Dave's issue was whether or not to offer breakers
that can be re-closed . . . for example, most production SE Cessnas
have push-only breakers. If one can justify putting those breakers
out of reach -or- replacing with no-flight-fiddling fuses, are
risks to the outcome of flight increased? I would suggest
that risks are decreased due to reduced pilot distraction as
long as one has a plan-B alternative for the most necessary
equipment items.
Bob . . .
>Paul
>
>
>----- Original Message -----
>From: "David Swartzendruber" <dswartzendruber@earthlink.net>
>To: <aeroelectric-list@matronics.com>
>Subject: AeroElectric-List: Resetting C/Bs
>
>
> > --> AeroElectric-List message posted by: "David Swartzendruber"
><dswartzendruber@earthlink.net>
> >
> > I'm involved in a discussion concerning resettable circuit protection
>verses
> > non-resettable in certified aircraft. Any resources you guys can
>recommend
> > would be appreciated.
> >
> > One of the challenges with the non-resettable argument for certified
> > aircraft is that after certification, an aircraft is hard to change. If
>it
> > gets through certification with a system that has nuisance tripping of the
> > circuit protection device, the owner is stuck with it. Therefore you have
> > the argument that you need to be able to reset the circuit breaker because
> > you can't fix the problem.
> >
> > The other argument I'm facing is that even though there may be a plan B
>when
> > plan A fails, plan A is more convenient. Therefore, if we can use plan A
> > even a few more times by simply resetting the circuit breaker, it's better
> > for the pilot.
> >
> > What I would like to determine is whether there is enough of a safety
>hazard
> > to resetting circuit breakers to offset the need to reset a poorly
>designed
> > system that can't be changed.
> >
> > Dave in Wichita
> >
> >
>
>
Bob . . .
|-------------------------------------------------------|
| The man who does not read good books has no advantage |
| over the man who cannot read them. |
| - Mark Twain |
|-------------------------------------------------------|
Message 12
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--> AeroElectric-List message posted by: cecilth@juno.com
I have shop radio noise.
AM Radio
I ran shielded cable to a roof antenna thats isolated from all metal.
Roof side grounded to ground pipe.
Radio side grounded to radio.
Have lots of ballasts in ceiling lights.
Can't seem to get rid of the noise while I work on my RV6A.
Do not archive.
Cecil needs help.
Message 13
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| Subject: | Re: Resetting C/Bs |
--> AeroElectric-List message posted by: "David Swartzendruber" <dswartzendruber@earthlink.net>
See comments below:
Dave in Wichita
> Why would a poorly designed system have to go to production?
> Surely we've got plenty of lessons learned from the past 5 decades
> of aircraft production. It's hard to beat good critical design review
> from a cadre of folks who understand the goals AND the
> history of where we've come from. In the final analysis,
> when in doubt, make it the next size bigger. There's nothing
> that prohibits you from piping power to a product on bigger
> wires than might otherwise be assumed adequate. Knowing the
> characteristics of the load is useful too . . . "Oh yeah,
> when it goes into the self cleaning mode, current draw
> is 50% above operating mode . . . we recommend you don't
> punch that button while airborne . . ." The questions
> that bite later are the ones not asked going in.
Perhaps the nuisance tripping situations I'm thinking of shouldn't really be
called nuisance tripping. Some of the failure modes I'm thinking of are
flap systems that get out of rig and allow the motor to drive to a hard
mechanical stop and pop the breaker. Reversing the direction and resetting
the breaker gets you back into business where a fuse wouldn't. I was told
by a pilot in on the discussion that he is flying a Cheyenne with the same
sort of problem with a deicing flap of some sort. The group I'm part of
would like to tell the world of certified airframers that we are the answer
to their electrical needs. From power generation, to complete distribution.
Some customers may not give us much freedom in redesigning the individual
systems, so we have to accomodate the quirks of the existing pieces of the
system as best we can. One of those quirks may be a failure mode where the
system could be recovered if the circuit protection device could be reset.
>
> No matter how convenient Plan A, there will always
> be a whole lot more failure modes that DON'T pop
> the breaker than the ones which DO pop the breaker.
> Likelihood of "saving the day" or even improving
> levels of comfort for having a breaker to punch
> is very low.
>
The response I got to that argument when I made it was that even if we are
only able to recover the system 1% of the times we reset the breaker, we
need to do it for the 1% of times because the assumption is that there is no
downside to the ability of being able to reset. This was with the premise
that cost and panel space were not a problem. If there was an additional
argument, such as safety, that could be made against resetting, it would go
a long way. The other part of the equation is that from a business
perspective, it may be easier to win over more potential customers if we
offered resettable circuit protection than if we have to go through this
same argument and convincing process with each customer.
It's very appealing to some to be able to offer a big "WOW" factor with
systems involving data busses that control and monitor everything, flat
screen control and warning panels that can display information in many
colors and allow you to control anything at the touch of a button. How can
a fuse and switch be "state of the art"?
The Cheyenne pilot I mentioned earlier said that you won't be able to get
pilots to give up the ability to do troubleshooting. That's why they go to
flight safety training and all that.
Message 14
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--> AeroElectric-List message posted by: "Tom FRIEDLAND" <beecho@neteze.com>
>No radio/nav was not really an option in IFR.
Not necessarily... I left DesMoine IFR for Denver when we lost the
generator and all battery power. (Army Beaver) We had gyros and a mag
compass and flew a direct compass course for 3 hours at our last
assigned altitude. We eventually saw Pikes Peak and got light signals
to clear to land. ATC had 7000 feet cleared for most of the Midwest!
Tom Friedland
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Subject: Re: AeroElectric-List: Resetting C/Bs
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
At 11:19 AM 3/29/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger"
><paulm@tenforward.com>
>
>I have had smoke in the cockpit in certificated acft a couple of times.
A
>master breaker saved my butt once as it was in IFR.
what's a "master breaker"?
> Turned out to be COM #2.
>breaker never opened as short was current limited and hist burned
internal
>to radio. The other case was the same but could have continued with
master
>off if needed.
>Had I not has a manually openable CB I am not sure how things would
have
>turned out. So its not just a CB but if you have one be sure you can
pull it
>open.
I'm surprised that the on/off switch for a radio didn't offer
a disconnect for everything powered within the radio.
>What I did was to pull the master and then each individual CB. reset
master
>and close others one at a time until source of smoke was found. No
radio/nav
>was not really an option in IFR.
>
>However all the cases of crashes etc from having resetable CB is from
the
>pilots or crews lack of the first rule of flight. FLY THE AIRPLANE
FIRST AND
>ALWAYS.
>
>Many pilots allow a problem to distract them and the result is usually
very
>bad. A simple problem crashed the acft because of pilot distraction.
>
>Thus I feel in most cases Bob is right. Design your acft so you can
keep
>going with no inflight trouble shooting needed.
I think Dave's issue was whether or not to offer breakers
that can be re-closed . . . for example, most production SE Cessnas
have push-only breakers. If one can justify putting those breakers
out of reach -or- replacing with no-flight-fiddling fuses, are
risks to the outcome of flight increased? I would suggest
that risks are decreased due to reduced pilot distraction as
long as one has a plan-B alternative for the most necessary
equipment items.
Bob . . .
>Paul
>
>
>----- Original Message -----
>From: "David Swartzendruber" <dswartzendruber@earthlink.net>
>To: <aeroelectric-list@matronics.com>
>Subject: AeroElectric-List: Resetting C/Bs
>
>
> > --> AeroElectric-List message posted by: "David Swartzendruber"
><dswartzendruber@earthlink.net>
> >
> > I'm involved in a discussion concerning resettable circuit
protection
>verses
> > non-resettable in certified aircraft. Any resources you guys can
>recommend
> > would be appreciated.
> >
> > One of the challenges with the non-resettable argument for certified
> > aircraft is that after certification, an aircraft is hard to change.
If
>it
> > gets through certification with a system that has nuisance tripping
of the
> > circuit protection device, the owner is stuck with it. Therefore
you have
> > the argument that you need to be able to reset the circuit breaker
because
> > you can't fix the problem.
> >
> > The other argument I'm facing is that even though there may be a
plan B
>when
> > plan A fails, plan A is more convenient. Therefore, if we can use
plan A
> > even a few more times by simply resetting the circuit breaker, it's
better
> > for the pilot.
> >
> > What I would like to determine is whether there is enough of a
safety
>hazard
> > to resetting circuit breakers to offset the need to reset a poorly
>designed
> > system that can't be changed.
> >
> > Dave in Wichita
> >
> >
>
>
Bob . . .
|-------------------------------------------------------|
| The man who does not read good books has no advantage |
| over the man who cannot read them. |
| - Mark Twain |
|-------------------------------------------------------|
Message 15
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| Subject: | Firewall penetration |
--> AeroElectric-List message posted by: Ron <rondefly@pacbell.net>
Hi Dave, I did not purchase mine, they were left over from a store I built
in the bay area CA, The owner of the store supplied all the hardware. i will
see if I can find out where they purchased them, Find a store that sells
bobrick hardware. I believe that was the kind. If not it would be pretty
easy to weld up some.
Ron Triano
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of David
Carter
Subject: AeroElectric-List: Firewall penetration
--> AeroElectric-List message posted by: "David Carter"
<dcarter@datarecall.net>
For Ron Triano, ref your e-mail to the list Sat March 1st,
I looked at stainless steel grab bars at Lowe's last night - $18 to $20
depending on length, 1 1/4" dia I think, with welded flange.
I'd rather have the 5/8 diameter that you are using. Can you tell us where
you bought it (or where we could buy it), manufacturer, part number? I
can't find any "towel racks" that have this stainless steel flange on hollow
tube feature. I suspect the 5/8 towel bar will be cheaper than the 1 1/4
dia grab bar.
David Carter
Message 16
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| Subject: | Re: Alternator Systems |
--> AeroElectric-List message posted by: Benford2@aol.com
In a message dated 3/29/2003 1:37:19 PM Mountain Standard Time,
bob.nuckolls@cox.net writes:
>
> I find no compelling reason to discourage anyone
> from taking advantage of modern, internally
> regulated alternators when fitted with a means
> for containing an overvoltage event. These
> alternators are demonstrably better products
> than those flying most certified ships today.
> Many OBAM aircraft owners have elected to run
> one-wire alternators without ov protection.
> The odds of a trouble free operation over the
> lifetime of the airplane are very much in their
> favor.
>
> Bob . . .
>
Once again I want to thank you for all your time you spend explaining the
finer details of the electrical systems. Not only are you VERY sharp in the
field you are willing to take time to help us all out in understanding the
workings of our charging systems. I hope we meet one day at a fly in because
you are getting a nice dinner paid for by me. Thanks again. Ben Haas. N801BH.
Jackson Hole WY.
Message 17
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| Subject: | Re: Firewall penetration |
--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
I used the 1 1/4 OD size - ran ALL off my engine wires through AN10 fire sleeve
(I think that was the size) and ran the fire sleeve throught the 1 1/4 OD firewall
fitting. The fitting I got had 3 mount holes in the flange - I mounted
the engine side with the tube pointing down at about a 45degree angle then on
the inside I mounted the other half facing straight up - maybe that's overkill
but I was able to use only the three holes in each flange. I was able to have
ALL my wires run through firesleeve to protect them from chaffing inside the
firewall fitting. Then to top it all off on the outside I put a larger firesleeve
around the entire bundle which will slide back over the outside of the
1 1/4 tube on the firewall fitting. I'll put a hose clamp on that piece to hold
it in place. It came out slick as can be. I highly recommend it. it is
loose enough so I might slip a couple more wires through without having to take
the fittings off the firewall. by the time you get everything run, it's quite
a big bundle of wires -I kept forgetting things -like 4 EGT & 4 CHT probe wires
take up some room if you get the ones shielded - and then they already have
the ends on them - so that complicates getting it through the tube - having
done it- you could never persuade me to go with smaller tube size. The only
other wire I ran was my Bat. buss wire - that's supposed to be only 6 inches
and I ran it using another rig.
my 2 cents for now.
David Carter <dcarter@datarecall.net> wrote:--> AeroElectric-List message posted
by: "David Carter"
For Ron Triano, ref your e-mail to the list Sat March 1st,
I looked at stainless steel grab bars at Lowe's last night - $18 to $20 depending
on length, 1 1/4" dia I think, with welded flange.
I'd rather have the 5/8 diameter that you are using. Can you tell us where you
bought it (or where we could buy it), manufacturer, part number? I can't find
any "towel racks" that have this stainless steel flange on hollow tube feature.
I suspect the 5/8 towel bar will be cheaper than the 1 1/4 dia grab bar.
David Carter
---------------------------------
Message 18
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| Subject: | Firewall penetration |
--> AeroElectric-List message posted by: Julia <wings97302@yahoo.com>
you want Franklin Brass (a Masco Company), #6424 - grab bar - 24 inch - stainless
steel, UPS code 0-79171-64245-6 - I got mine at home depot. once in a while
I have a good idea and this one is REALLY good. mines all done and looks
totally awesome.
Ron <rondefly@pacbell.net> wrote:--> AeroElectric-List message posted by: Ron
Hi Dave, I did not purchase mine, they were left over from a store I built
in the bay area CA, The owner of the store supplied all the hardware. i will
see if I can find out where they purchased them, Find a store that sells
bobrick hardware. I believe that was the kind. If not it would be pretty
easy to weld up some.
Ron Triano
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of David
Carter
Subject: AeroElectric-List: Firewall penetration
--> AeroElectric-List message posted by: "David Carter"
For Ron Triano, ref your e-mail to the list Sat March 1st,
I looked at stainless steel grab bars at Lowe's last night - $18 to $20
depending on length, 1 1/4" dia I think, with welded flange.
I'd rather have the 5/8 diameter that you are using. Can you tell us where
you bought it (or where we could buy it), manufacturer, part number? I
can't find any "towel racks" that have this stainless steel flange on hollow
tube feature. I suspect the 5/8 towel bar will be cheaper than the 1 1/4
dia grab bar.
David Carter
---------------------------------
Message 19
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| Subject: | question on alternators/controllers |
--> AeroElectric-List message posted by: Aucountry@aol.com
I Just finished the installation of an overhauled alternator (Aeroelectrics)
and new Zeftronics alternaor controller in a Piper PA-24-250 Comanche.=A0 =20I
replaced all of the the wires firewall forward.=A0 New ground wires.=A0
Dedicated ground wire from the alternator to the alternator controller.=A0 =20
On
engine start, the ammeter goes up like expected then decreases as expected.=A0
The voltage readout on a digital ammeter/voltmeter on the avionics side of
the bus bar shows 12.6 volts at idle and 13.0 volts at 1500 RPM.=A0 The
voltage readout on the JPI 700 at the same time is 13.0 volts at idle and
13.4 volts at 1500 RPM.=A0 At 1500 RPM with ALL of the switches turned on=20is
12.1 volts on the avionics side and 12.4 on the JPI 700.=A0 The ammeter under
a full load shows about 0.0 amps plus or MINUS 0.2 amps.
Now, had this been the first time this has happened I'd say more trouble
shooting is called for.=A0 However.=A0 I installed an overhauled (from
AVIALL) alternator and Zeftronics controller on a Tiger about a year ago and
his JPI 700 showed a consistant 12.6 to 13.2 volts under most conditions.=A0
I did the usual and cleaned the grounds, replaced the Master Switch, and
cleaned all connections.=A0 Still no change.=A0 The owner decided to take the
plane and if there were any problems with the battery not staying charged
he'd get back to me.=A0 So far, the battery has stayed charged.=A0
Can the voltage be set on the alternator controllers?=A0 Is there something
else I should be looking at or for?
Gary
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