Today's Message Index:
----------------------
1. 04:48 AM - Strange breaker issues (Brett Ferrell)
2. 05:19 AM - Re: Strange breaker issues (Rob Turk)
3. 05:41 AM - Re: Strange breaker issues (Brett Ferrell)
4. 05:51 AM - Re: Strange breaker issues (Matt Prather)
5. 06:02 AM - Re: Strange breaker issues (Robert L. Nuckolls, III)
6. 06:07 AM - Re: Figure Z-8 (Robert L. Nuckolls, III)
7. 06:54 AM - Re: Z-19 and considerations of SYSTEM reliability (Robert L. Nuckolls, III)
8. 07:18 AM - Re: Strange breaker issues (paul wilson)
9. 07:29 AM - making fuseable links (CardinalNSB@aol.com)
10. 07:33 AM - el cheapo battery tester (CardinalNSB@aol.com)
11. 07:42 AM - Re: Figure Z-8 (SkipperClyde)
12. 08:01 AM - Re: making fuseable links (Robert L. Nuckolls, III)
13. 08:11 AM - Re: Re: Figure Z-8 (Robert L. Nuckolls, III)
14. 08:20 AM - Re: Re: Z-19 and considerations of SYSTEM reliability (Allen Fulmer)
15. 08:37 AM - Re: el cheapo battery tester (Robert L. Nuckolls, III)
16. 09:15 AM - Yaesu VXA-100 external PTT (Bob Bittner)
17. 10:04 AM - Re: Re: Z-19 and considerations of SYSTEM reliability ()
18. 10:12 AM - Re: making fuseable links ()
19. 10:32 AM - A look at the future - Perhaps a wiring system that could fit into the palm of your hand ()
20. 01:34 PM - Re: making fuseable links (Ken)
21. 02:05 PM - Ground loop risk? (Neil Clayton)
Message 1
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| Subject: | Strange breaker issues |
Bob/all,
I have a strange issue with my newly flying homebuilt Velocity. My nav
light breaker keeps tripping, but only when the engine is running. If I
turn on the nav lights (red/green/two rear-facing whites of a Whelen
wingtip kit, supposed to pull 2A - it's not clear if that's a piece or
together, are on a 5A Klixon breaker), without the engine running they
will stay lighted for long periods of time without issue (easily over a
half hour during testing, even with the strobes and other loads on, or
without other loads). However, when I turn them on with the engine
running, the breaker trips within 5 minutes typically.
My first thought was to remove one load at a time to see if one of my
molex connectors had a partial short, or if they were just pulling too
much load together, so I started this test in the hangar and found it
wouldn't trip in the hangar.
Other, probably not relevant data:
1) all uses have dedicated direct ground wires due to composite construction
2) grounds are routed on a common ground bus on 1 ground that runs from
the engine at back to a forest of tabs at the rear firewall, and a set
of tabs on the canard, to the battery
3) set up as dual-alternator, single battery system
4) engine uses electronic ignition
5) the (rear-mounted) alternators use current limiters on the firewall,
not breakers in the panel
Brett
Message 2
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| Subject: | Re: Strange breaker issues |
If these Whelen strobe/nav lights are like mine they draw close to 7A. Maybe
they draw 5A when running on 12V battery power, and it goes up a bit to 7A
when you start the engine and your ships power goes to 14V.
Rob
----- Original Message -----
From: "Brett Ferrell" <bferrell@123mail.net>
Sent: Friday, October 12, 2007 1:46 PM
Subject: AeroElectric-List: Strange breaker issues
> <bferrell@123mail.net>
>
> Bob/all,
>
> I have a strange issue with my newly flying homebuilt Velocity. My nav
> light breaker keeps tripping, but only when the engine is running. If I
> turn on the nav lights (red/green/two rear-facing whites of a Whelen
> wingtip kit, supposed to pull 2A - it's not clear if that's a piece or
> together, are on a 5A Klixon breaker), without the engine running they
> will stay lighted for long periods of time without issue (easily over a
> half hour during testing, even with the strobes and other loads on, or
> without other loads). However, when I turn them on with the engine
> running, the breaker trips within 5 minutes typically.
>
Message 3
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| Subject: | Re: Strange breaker issues |
I've got the stobes switched and 'breakered' separately with a 7A Klixon. The
wingtip position/nav (A600 PG/PR) lights, which are clearly shown as 4 amps at
14V on page 24 of thier documentation, but here I see the wattage (26 and 24,
respectively) for the first time, and so it does appear that is the "total
power consumption" for one Lamp Assembly (forward and aft) but not the pair....
Oops.
http://www.whelen.com/pb/Aviation/Anti-Collision_Light_Systems_Installation_and_Service_Manual.pdf
Brett
Quoting Rob Turk <matronics@rtist.nl>:
>
> If these Whelen strobe/nav lights are like mine they draw close to 7A. Maybe
> they draw 5A when running on 12V battery power, and it goes up a bit to 7A
> when you start the engine and your ships power goes to 14V.
>
> Rob
>
> ----- Original Message -----
> From: "Brett Ferrell" <bferrell@123mail.net>
> To: <aeroelectric-list@matronics.com>
> Sent: Friday, October 12, 2007 1:46 PM
> Subject: AeroElectric-List: Strange breaker issues
>
>
> > <bferrell@123mail.net>
> >
> > Bob/all,
> >
> > I have a strange issue with my newly flying homebuilt Velocity. My nav
> > light breaker keeps tripping, but only when the engine is running. If I
> > turn on the nav lights (red/green/two rear-facing whites of a Whelen
> > wingtip kit, supposed to pull 2A - it's not clear if that's a piece or
> > together, are on a 5A Klixon breaker), without the engine running they
> > will stay lighted for long periods of time without issue (easily over a
> > half hour during testing, even with the strobes and other loads on, or
> > without other loads). However, when I turn them on with the engine
> > running, the breaker trips within 5 minutes typically.
> >
>
>
Message 4
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| Subject: | Re: Strange breaker issues |
2A sounds low for nav lights. Is this a 12/14V system, or 24/28V? Are
these LED lights or conventional incandescent bulbs? If conventional
bulbs, I think you can count on at least 5A for the system. When the
engine is running the bus voltage comes up, and since lights aren't
constant power devices, they will draw more current - popping the breaker.
At least that's my theory...
Regards,
Matt-
> <bferrell@123mail.net>
>
> Bob/all,
>
> I have a strange issue with my newly flying homebuilt Velocity. My nav
> light breaker keeps tripping, but only when the engine is running. If I
> turn on the nav lights (red/green/two rear-facing whites of a Whelen
> wingtip kit, supposed to pull 2A - it's not clear if that's a piece or
> together, are on a 5A Klixon breaker), without the engine running they
> will stay lighted for long periods of time without issue (easily over a
> half hour during testing, even with the strobes and other loads on, or
> without other loads). However, when I turn them on with the engine
> running, the breaker trips within 5 minutes typically.
>
> My first thought was to remove one load at a time to see if one of my
> molex connectors had a partial short, or if they were just pulling too
> much load together, so I started this test in the hangar and found it
> wouldn't trip in the hangar.
>
> Other, probably not relevant data:
> 1) all uses have dedicated direct ground wires due to composite
> construction
> 2) grounds are routed on a common ground bus on 1 ground that runs from
> the engine at back to a forest of tabs at the rear firewall, and a set
> of tabs on the canard, to the battery
> 3) set up as dual-alternator, single battery system
> 4) engine uses electronic ignition
> 5) the (rear-mounted) alternators use current limiters on the firewall,
> not breakers in the panel
>
> Brett
>
>
Message 5
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| Subject: | Re: Strange breaker issues |
At 06:46 AM 10/12/2007 -0500, you wrote:
>
>Bob/all,
>
>I have a strange issue with my newly flying homebuilt Velocity. My nav
>light breaker keeps tripping, but only when the engine is running. If I
>turn on the nav lights (red/green/two rear-facing whites of a Whelen
>wingtip kit, supposed to pull 2A - it's not clear if that's a piece or
>together, are on a 5A Klixon breaker), without the engine running they
>will stay lighted for long periods of time without issue (easily over a
>half hour during testing, even with the strobes and other loads on, or
>without other loads). However, when I turn them on with the engine
>running, the breaker trips within 5 minutes typically.
>
>My first thought was to remove one load at a time to see if one of my
>molex connectors had a partial short, or if they were just pulling too
>much load together, so I started this test in the hangar and found it
>wouldn't trip in the hangar.
>
>Other, probably not relevant data:
>1) all uses have dedicated direct ground wires due to composite construction
>2) grounds are routed on a common ground bus on 1 ground that runs from
>the engine at back to a forest of tabs at the rear firewall, and a set of
>tabs on the canard, to the battery
>3) set up as dual-alternator, single battery system
>4) engine uses electronic ignition
>5) the (rear-mounted) alternators use current limiters on the firewall,
>not breakers in the panel
Nav lamps are typically 2A PER BULB. Your total
draw on this system could be as much as 8A with
the alternator on line. Get your meter out and
measure it.
Bob . . .
----------------------------------------
( "Problems are the price of progress. )
( Don't bring me anything but trouble. )
( Good news weakens me." )
( -Charles F. Kettering- )
----------------------------------------
Message 6
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At 06:51 PM 10/11/2007 -0700, you wrote:
><jandlhussey@sbcglobal.net>
>
>Greetings,
> I'm new at this please be gentle. Other than a new switch (Off-Master
> on- Master on, Alternator on) have there been any corrections/changes to
> Figure Z-8. I can't seem to find the drawing on line. Can anybody provide
> a link?
> Thank you in advance.
Figures Z-1 through Z-10 were replaced with a new
series Z-11 and up which are published at:
http://aeroelectric.com/articles/Rev11/AppZ_R11K.pdf
Sounds like you're working with a copy of the 'Connection
that is quite old.
Bob . . .
----------------------------------------
( "Problems are the price of progress. )
( Don't bring me anything but trouble. )
( Good news weakens me." )
( -Charles F. Kettering- )
----------------------------------------
Message 7
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| Subject: | RE: Z-19 and considerations of SYSTEM reliability |
At 08:16 PM 10/11/2007 -0500, you wrote:
>
>By the way, Bob, both Z19 and Z19RB (rear battery) have 2 fuel pumps
>depicted (the Eggenfellner Subs. have 2 pumps).
>While Z19 only has a switch to control Pump #2, I don't see any problem with
>adding a pressure fail-over switch to automatically turn on #2 in the event
>#1 quits pumping.
Oh yeah, THAT #2 pump switch. Having a sr. moment here.
"Automatic" features are not necessarily "problems",
but they add to parts count which drives up probability
of a SYSTEM failure. For example:
I did what I believe was the first speed controlled
pitch trim system on the Lear 55 and ultimately the
30 series fleet about 1980. The speed control board
was pretty simple and fit on about 3 x 3" of copper-clad.
Then the systems guys began to worry about failures
of the speed control system and levied some requirements
for monitoring and warning. Over the past 25 years,
the preponderance of failures have been in the warning
system . . . and the failures in the speed control system
that produced a too-fast motor were less than 1% of all
failures. The monitor board was about twice the parts
count and accounts for most of the cost-of-ownership
for the system. It catches only 1% of all failures which
turned out to be so benign that the monitor board wasn't
really necessary after all.
My cautionary comments go to the fact that the more
complex your airplane becomes as a complete flight system,
the more it costs you to maintain it and the more likely
it is to present an in-flight conundrum to be pondered
and reacted to. A part that is not present is not going
to be the part that generates an in-flight distraction
or and on-the-ground maintenance event.
Your task as a system integrator is deducing
the return on investment for adding ANY components
to your system. What is the value of that device in
reducing the probability of breaking a sweat while
airborne? My second car was a '57 Chevy BelAir with
all the goodies on it. My third car was a '59 Chevy
six-cylinder, stick shift with no goodies. Subsequent
cars were similarly lacking in fluff. I learned very
quickly that my best return on investment was the simplest
combination of hardware that provided comfortable,
reliable, lowest cost, easiest to maintain transport
from point A to point B.
Our low-wing, TC aircraft have been fitted with
boost pumps since day one. 95+ percent of all engine
falters in flight have to do with fuel issues.
We were taught to hit the pump switch first. Perception,
interpretation and reaction took perhaps two seconds.
. . . and the pump is already ON for takeoff and
landing. So, what is the return on investment of
adding an automatic "failover" device in those aircraft?
Now, if these engines tend to quit and be hard to
get restarted then perhaps some form of automatic,
fast reaction system is called for. But if it just
falters, windmills and recovers immediately upon
return of fuel flow, then perhaps the automatic
system is less than elegant. THAT decision is
entirely yours . . . I'm only suggesting that
you ponder the decision with good data and a goal
of arriving at the elegant solution.
Bob . . .
Message 8
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| Subject: | Re: Strange breaker issues |
I measured a pair cold and it is close to 7A measured at the bulb end
ignoring the wiring. Suggest you use a 10a CB and be sure the wire
can deal with the amps.
Paul
===========
At 06:40 AM 10/12/2007, you wrote:
>
>I've got the stobes switched and 'breakered' separately with a 7A Klixon. The
>wingtip position/nav (A600 PG/PR) lights, which are clearly shown as 4 amps at
>14V on page 24 of thier documentation, but here I see the wattage (26 and 24,
>respectively) for the first time, and so it does appear that is the "total
>power consumption" for one Lamp Assembly (forward and aft) but not
>the pair....
> Oops.
>
>http://www.whelen.com/pb/Aviation/Anti-Collision_Light_Systems_Installation_and_Service_Manual.pdf
>
>Brett
>
>Quoting Rob Turk <matronics@rtist.nl>:
>
> >
> > If these Whelen strobe/nav lights are like mine they draw close
> to 7A. Maybe
> > they draw 5A when running on 12V battery power, and it goes up a bit to 7A
> > when you start the engine and your ships power goes to 14V.
> >
> > Rob
> >
> > ----- Original Message -----
> > From: "Brett Ferrell" <bferrell@123mail.net>
> > To: <aeroelectric-list@matronics.com>
> > Sent: Friday, October 12, 2007 1:46 PM
> > Subject: AeroElectric-List: Strange breaker issues
> >
> >
> > > <bferrell@123mail.net>
> > >
> > > Bob/all,
> > >
> > > I have a strange issue with my newly flying homebuilt Velocity. My nav
> > > light breaker keeps tripping, but only when the engine is running. If I
> > > turn on the nav lights (red/green/two rear-facing whites of a Whelen
> > > wingtip kit, supposed to pull 2A - it's not clear if that's a piece or
> > > together, are on a 5A Klixon breaker), without the engine running they
> > > will stay lighted for long periods of time without issue (easily over a
> > > half hour during testing, even with the strobes and other loads on, or
> > > without other loads). However, when I turn them on with the engine
> > > running, the breaker trips within 5 minutes typically.
> > >
> >
> >
> >
> >
> >
> >
>
Message 9
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| Subject: | making fuseable links |
Please critique this idea for making fuseable link for #20 wire (ammeter
shunt, for instance)
Instead of soldering in a piece #24 wire at the end, what if I just stripped
a 2 inch "gap" and then carefully chisled out, perhaps half or so of the
strands.
Is there a milspec of 20 gauge wire that uses the same strands as #24, so as
to maintain the flexability of the smaller wire gauge wire "link".
Am I correct that the reason for splicing the link into both ends of the
protected wire is for physical strength, as opposed to crimping the link portion
to the appliance with only connection to be made to the protected wire?
Question, in the drawings the insulating sleeve is looking "loose" over the
fuseable link, is this a necessary design element, or would a tight fitting
fireproof sleeve work as well?
Thanks, Skip
Message 10
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| Subject: | el cheapo battery tester |
I coldn't resist the $16 battery tester on sale at Harbor Freight, for 12
volt batteries, it says for CCA up to 1000 amps and is rated at 100 amps.
Will this cause harm to "regular car batteries, flooded wet cells", and to
Odyssey type sla batteries?
The security shop next door throws out batteries all the time, out of about
20 I got out of the trash over the years 2 have held voltage overnight, but I
have never relied on them for anything.
What is the best way to use this product to test both types of batteries, or
should I go get my money back?
Thanks, Skip
Message 11
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Bob
I have appendix Z dated 04/05. I was working from Figure Z-11 Generic light Aircraft
Electrical System, which looks to be exactly what I need.
Looking through the revision 07/06 I don't find a similar Figure Z-11 but Z13/8
comes close.
Are there problems with the original Z-11 or should I look to find something out
of the new revision to model my system after.
thanks
phil
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=139573#139573
Message 12
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| Subject: | Re: making fuseable links |
At 10:27 AM 10/12/2007 -0400, you wrote:
>Please critique this idea for making fuseable link for #20 wire (ammeter
>shunt, for instance)
>
>Instead of soldering in a piece #24 wire at the end, what if I just
>stripped a 2 inch "gap" and then carefully chisled out, perhaps half or so
>of the strands.
>
>Is there a milspec of 20 gauge wire that uses the same strands as #24, so
>as to maintain the flexability of the smaller wire gauge wire "link".
>
>Am I correct that the reason for splicing the link into both ends of the
>protected wire is for physical strength, as opposed to crimping the link
>portion to the appliance with only connection to be made to the protected wire?
>
>Question, in the drawings the insulating sleeve is looking "loose" over
>the fuseable link, is this a necessary design element, or would a tight
>fitting fireproof sleeve work as well?
>
>Thanks, Skip
Do some experiments and find out. What you propose
seems feasible . . . the processes and materials
depicted have been bench and field tested. If you
have your own recipe for success to explore and
offer to the community, we'd be pleased to know
it. We can hypothesize a lot of variations on the
theme but the proof of the pudding is in the
tasting.
Bob . . .
Message 13
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At 07:41 AM 10/12/2007 -0700, you wrote:
>
>Bob
>
>I have appendix Z dated 04/05. I was working from Figure Z-11 Generic
>light Aircraft Electrical System, which looks to be exactly what I need.
>
>Looking through the revision 07/06 I don't find a similar Figure Z-11 but
>Z13/8 comes close.
>
>Are there problems with the original Z-11 or should I look to find
>something out of the new revision to model my system after.
I'm lost now. We started off with a discussion about Z-8, I take
it that's a typo and perhaps Z-13/8 was the real reference.
Z-11 is essentially unchanged with respect to architecture.
The modifications were to clarify part numbers and perhaps
make some substitutions. I think it used to have the B&C LR3
regulator and now shows a generic Ford product.
Keep in mind that these are ARCHITECTURE drawings. Various
features and component selections are sort of mix-n-match
between the drawings and should be accomplished as your
personal needs and situation dictates. If it were my airplane,
Z-13/8 would be the architecture of choice.
Bob . . .
Message 14
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| Subject: | RE: Z-19 and considerations of SYSTEM reliability |
Thanks Bob,
I can't seem to find the email but I think Eggenfellner has decided that a
simple switch on Pump#2 is fine. They were having too much trouble with the
pressure switch for automatic fail-over.
As a computer geek I find it so hard to resist "automatic techno gadgets"!
Thanks for the detailed exhortation.
Allen Fulmer
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert
L. Nuckolls, III
Sent: Friday, October 12, 2007 9:54 AM
Subject: AeroElectric-List: RE: Z-19 and considerations of SYSTEM
reliability
<nuckolls.bob@cox.net>
At 08:16 PM 10/11/2007 -0500, you wrote:
<afulmer@charter.net>
>
>By the way, Bob, both Z19 and Z19RB (rear battery) have 2 fuel pumps
>depicted (the Eggenfellner Subs. have 2 pumps).
>While Z19 only has a switch to control Pump #2, I don't see any problem
with
>adding a pressure fail-over switch to automatically turn on #2 in the event
>#1 quits pumping.
Oh yeah, THAT #2 pump switch. Having a sr. moment here.
"Automatic" features are not necessarily "problems",
but they add to parts count which drives up probability
of a SYSTEM failure. For example:
I did what I believe was the first speed controlled
pitch trim system on the Lear 55 and ultimately the
30 series fleet about 1980. The speed control board
was pretty simple and fit on about 3 x 3" of copper-clad.
Then the systems guys began to worry about failures
of the speed control system and levied some requirements
for monitoring and warning. Over the past 25 years,
the preponderance of failures have been in the warning
system . . . and the failures in the speed control system
that produced a too-fast motor were less than 1% of all
failures. The monitor board was about twice the parts
count and accounts for most of the cost-of-ownership
for the system. It catches only 1% of all failures which
turned out to be so benign that the monitor board wasn't
really necessary after all.
My cautionary comments go to the fact that the more
complex your airplane becomes as a complete flight system,
the more it costs you to maintain it and the more likely
it is to present an in-flight conundrum to be pondered
and reacted to. A part that is not present is not going
to be the part that generates an in-flight distraction
or and on-the-ground maintenance event.
Your task as a system integrator is deducing
the return on investment for adding ANY components
to your system. What is the value of that device in
reducing the probability of breaking a sweat while
airborne? My second car was a '57 Chevy BelAir with
all the goodies on it. My third car was a '59 Chevy
six-cylinder, stick shift with no goodies. Subsequent
cars were similarly lacking in fluff. I learned very
quickly that my best return on investment was the simplest
combination of hardware that provided comfortable,
reliable, lowest cost, easiest to maintain transport
from point A to point B.
Our low-wing, TC aircraft have been fitted with
boost pumps since day one. 95+ percent of all engine
falters in flight have to do with fuel issues.
We were taught to hit the pump switch first. Perception,
interpretation and reaction took perhaps two seconds.
. . . and the pump is already ON for takeoff and
landing. So, what is the return on investment of
adding an automatic "failover" device in those aircraft?
Now, if these engines tend to quit and be hard to
get restarted then perhaps some form of automatic,
fast reaction system is called for. But if it just
falters, windmills and recovers immediately upon
return of fuel flow, then perhaps the automatic
system is less than elegant. THAT decision is
entirely yours . . . I'm only suggesting that
you ponder the decision with good data and a goal
of arriving at the elegant solution.
Bob . . .
Message 15
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| Subject: | Re: el cheapo battery tester |
At 10:31 AM 10/12/2007 -0400, you wrote:
>I coldn't resist the $16 battery tester on sale at Harbor Freight, for 12
>volt batteries, it says for CCA up to 1000 amps and is rated at 100 amps.
>
>Will this cause harm to "regular car batteries, flooded wet cells", and
>to Odyssey type sla batteries?
>
>The security shop next door throws out batteries all the time, out of
>about 20 I got out of the trash over the years 2 have held voltage
>overnight, but I have never relied on them for anything.
>
>What is the best way to use this product to test both types of batteries,
>or should I go get my money back?
>
>Thanks, Skip
The tester you have has some utility. In spite of the
claims as to what it's capable of doing, the simplest
description of functionality says it will put a signifiant
load (50+ amps) on a battery to demonstrate it's ability
to carry a load. I suspect it's similar to this device:
http://www.aeroelectric.com/Pictures/Tools/Battery_Testers/HF_Resistor_Load.jpg
While more portable and convenient than hooking the
battery to your car and measuring terminal voltage while
cranking, the fixed resistor tester is a simple, gross
look at a battery's performance but not very quantitative.
The next step up is a tester like this:
http://www.aeroelectric.com/Pictures/Tools/Battery_Testers/HF_Carbon_Pile_Load.jpg
Here the goal is to put as much load on the battery as it
will tolerate while holding terminal voltage at the bottom
of the green arc appropriate to the battery's temperature.
There's a timer and buzzer in the tester that starts
when you crank up the current.
http://www.aeroelectric.com/Pictures/Tools/Battery_Testers/HF91129_2.jpg
When the buzzer goes off at 15 seconds, read the current
that the battery will support at the voltage appropriate
to the temperature. This is a MEASURE of that battery's
ability to crank an engine.
CAPACITY is another matter entirely. To make this determination,
you need to deplete and measure the energy the battery will
deliver at a load current of interest (like your e-bus loads).
This takes a device like:
http://www.aeroelectric.com/Pictures/Tools/Battery_Testers/CBA2_1.jpg
To make a learned decision as to the suitability of
any battery to do a task, you should consider both
short term high current, low-energy loads and long
term, low current, high-energy loads.
The tester you have is a good value but it's limited.
It does not tell you everything you'd really like to know
about any given battery.
Bob . . .
----------------------------------------
( "Problems are the price of progress. )
( Don't bring me anything but trouble. )
( Good news weakens me." )
( -Charles F. Kettering- )
----------------------------------------
Message 16
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| Subject: | Yaesu VXA-100 external PTT |
Hi.
I have a Yaesu VXA-100 and the Yaesu external headset adapter cable. The
standard PTT switch (which works fine with other radios & intercoms) does
not work on this handheld/cable combination. It does not trigger tx.
Is anyone out there using a Yaesu handheld radio with an external PTT?
Do you have a wiring diagram that shows how to hook in an external PTT?
Thanks.
---------------------------------------------- >+
Bob Bittner
Message 17
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| Subject: | RE: Z-19 and considerations of SYSTEM reliability |
Et al,
Thanks for all the input. I will go the 2 switch route and decide
whether it is more elegant to hang them off each bus as shown by #2 in
the diag, or incorporate them behind the diodes for primary and
secondary power. Either option should provide the same level of
redundancy. I am very excited to lay this out for real.
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Allen
Fulmer
Sent: Friday, October 12, 2007 11:21 AM
Subject: RE: AeroElectric-List: RE: Z-19 and considerations of SYSTEM
reliability
--> <afulmer@charter.net>
Thanks Bob,
I can't seem to find the email but I think Eggenfellner has decided that
a simple switch on Pump#2 is fine. They were having too much trouble
with the pressure switch for automatic fail-over.
As a computer geek I find it so hard to resist "automatic techno
gadgets"! Thanks for the detailed exhortation.
Allen Fulmer
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert
L. Nuckolls, III
Sent: Friday, October 12, 2007 9:54 AM
Subject: AeroElectric-List: RE: Z-19 and considerations of SYSTEM
reliability
<nuckolls.bob@cox.net>
At 08:16 PM 10/11/2007 -0500, you wrote:
<afulmer@charter.net>
>
>By the way, Bob, both Z19 and Z19RB (rear battery) have 2 fuel pumps
>depicted (the Eggenfellner Subs. have 2 pumps).
>While Z19 only has a switch to control Pump #2, I don't see any problem
with
>adding a pressure fail-over switch to automatically turn on #2 in the
>event #1 quits pumping.
Oh yeah, THAT #2 pump switch. Having a sr. moment here.
"Automatic" features are not necessarily "problems",
but they add to parts count which drives up probability
of a SYSTEM failure. For example:
I did what I believe was the first speed controlled
pitch trim system on the Lear 55 and ultimately the
30 series fleet about 1980. The speed control board
was pretty simple and fit on about 3 x 3" of copper-clad.
Then the systems guys began to worry about failures
of the speed control system and levied some requirements
for monitoring and warning. Over the past 25 years,
the preponderance of failures have been in the warning
system . . . and the failures in the speed control system
that produced a too-fast motor were less than 1% of all
failures. The monitor board was about twice the parts
count and accounts for most of the cost-of-ownership
for the system. It catches only 1% of all failures which
turned out to be so benign that the monitor board wasn't
really necessary after all.
My cautionary comments go to the fact that the more
complex your airplane becomes as a complete flight system,
the more it costs you to maintain it and the more likely
it is to present an in-flight conundrum to be pondered
and reacted to. A part that is not present is not going
to be the part that generates an in-flight distraction
or and on-the-ground maintenance event.
Your task as a system integrator is deducing
the return on investment for adding ANY components
to your system. What is the value of that device in
reducing the probability of breaking a sweat while
airborne? My second car was a '57 Chevy BelAir with
all the goodies on it. My third car was a '59 Chevy
six-cylinder, stick shift with no goodies. Subsequent
cars were similarly lacking in fluff. I learned very
quickly that my best return on investment was the simplest
combination of hardware that provided comfortable,
reliable, lowest cost, easiest to maintain transport
from point A to point B.
Our low-wing, TC aircraft have been fitted with
boost pumps since day one. 95+ percent of all engine
falters in flight have to do with fuel issues.
We were taught to hit the pump switch first. Perception,
interpretation and reaction took perhaps two seconds.
. . . and the pump is already ON for takeoff and
landing. So, what is the return on investment of
adding an automatic "failover" device in those aircraft?
Now, if these engines tend to quit and be hard to
get restarted then perhaps some form of automatic,
fast reaction system is called for. But if it just
falters, windmills and recovers immediately upon
return of fuel flow, then perhaps the automatic
system is less than elegant. THAT decision is
entirely yours . . . I'm only suggesting that
you ponder the decision with good data and a goal
of arriving at the elegant solution.
Bob . . .
Message 18
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| Subject: | making fuseable links |
Why not just find and use a 20 AWG fuse link? Are we worried about
corrosion or some kind of electron acceleration over a 6" fuse link? For
that matter to make it really elegant, have a custom 20 AWG fuse link
made (or make it yourself) that is seamless between the shunt and the
load meter. Two less connections to worry about.
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Sent: Friday, October 12, 2007 12:01 PM
Subject: Re: AeroElectric-List: making fuseable links
--> <nuckolls.bob@cox.net>
At 10:27 AM 10/12/2007 -0400, you wrote:
>Please critique this idea for making fuseable link for #20 wire
>(ammeter
>shunt, for instance)
>
>Instead of soldering in a piece #24 wire at the end, what if I just
>stripped a 2 inch "gap" and then carefully chisled out, perhaps half or
so
>of the strands.
>
>Is there a milspec of 20 gauge wire that uses the same strands as #24,
>so
>as to maintain the flexability of the smaller wire gauge wire "link".
>
>Am I correct that the reason for splicing the link into both ends of
>the
>protected wire is for physical strength, as opposed to crimping the
link
>portion to the appliance with only connection to be made to the
protected wire?
>
>Question, in the drawings the insulating sleeve is looking "loose" over
>the fuseable link, is this a necessary design element, or would a tight
>fitting fireproof sleeve work as well?
>
>Thanks, Skip
Do some experiments and find out. What you propose
seems feasible . . . the processes and materials
depicted have been bench and field tested. If you
have your own recipe for success to explore and
offer to the community, we'd be pleased to know
it. We can hypothesize a lot of variations on the
theme but the proof of the pudding is in the
tasting.
Bob . . .
Message 19
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| Subject: | A look at the future - Perhaps a wiring system that |
could fit into the palm of your hand
Or at least a new material for making diodes and chip material. How
about an EFIS as thin as a wafer?
Nanowire
http://news.rpi.edu/update.do?artcenterkey=1883
Nanotube sandwich your next carbon fibre aircraft. This is a very kool
concept as nanotube weaving could cut the weight of your already light
carbon aircraft and allow you to keep the strength and power.
http://news.rpi.edu/update.do?artcenterkey=1545
Rennselaer Nano Home
http://www.rpi.edu/research/nanotechnology/index.html
NANOTUBES DETECT, REPAIR WING DAMAGE
Adding even a small amount of carbon "nanotubes" can go a long way
toward enhancing the strength, integrity, and safety of composite
structures, according to a new study at Rensselaer Polytechnic
Institute, New York. Researchers there have developed a simple new
technique for identifying and repairing small, potentially dangerous
cracks in high-performance aircraft wings and many other composite
structures. By infusing the polymer with electrically conductive carbon
nanotubes and monitoring the electrical resistance at different points
in the structure, Professor Nikhil Koratkar, who developed the method,
can pinpoint the location and length of even the tiniest stress-induced
crack.
Once a crack is located, Koratkar can then send a short electrical
charge to the area in order to heat up the carbon nanotubes and in turn
melt an embedded healing agent that will flow into and seal the crack.
"What's novel about this application is that we're using carbon
nanotubes not just to detect the crack, but also to heal the crack,"
Koratkar said. "We use the nanotubes to create localized heat, which
melts the healing agent, and that's what cures the crack." To learn
more, visit www.rpi.edu <http://www.rpi.edu/> .
Message 20
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| Subject: | Re: making fuseable links |
I would suspect that such a "fuse link" would allow the wire immediately
downstream of it to get hotter than the wire farther from the link.
Basically we would be expecting some current to pass from the continuous
strands to the broken strands and hope that the rest of the wire would
share current equally in all strands from that point. Any corrosion
would further degrade that and I would expect the continuous strands to
run hotter outside the link than we might like prior to the fuse link
open circuiting. I'd guess the risk is probably small but the wire
insulation is not equivalent to the glass spaghetti that I have around
my fuse link segments and I can't imagine any commercial product
utilizing such a method. If I wanted to use this method I would still
solder the point that transitions to all strands.
FWIW I found it easy to solder in fuse links and immobilize the solder
joint with a few layers of heat shrink or silicone tape.
Ken
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@cox.net>
>
> At 10:27 AM 10/12/2007 -0400, you wrote:
>
>> Please critique this idea for making fuseable link for #20 wire
>> (ammeter shunt, for instance)
>>
>> Instead of soldering in a piece #24 wire at the end, what if I just
>> stripped a 2 inch "gap" and then carefully chisled out, perhaps half
>> or so of the strands.
>>
>> Is there a milspec of 20 gauge wire that uses the same strands as
>> #24, so as to maintain the flexability of the smaller wire gauge wire
>> "link".
>>
>> Am I correct that the reason for splicing the link into both ends of
>> the protected wire is for physical strength, as opposed to crimping
>> the link portion to the appliance with only connection to be made to
>> the protected wire?
>>
>> Question, in the drawings the insulating sleeve is looking "loose"
>> over the fuseable link, is this a necessary design element, or would
>> a tight fitting fireproof sleeve work as well?
>>
>> Thanks, Skip
>
>
> Do some experiments and find out. What you propose
> seems feasible . . . the processes and materials
> depicted have been bench and field tested. If you
> have your own recipe for success to explore and
> offer to the community, we'd be pleased to know
> it. We can hypothesize a lot of variations on the
> theme but the proof of the pudding is in the
> tasting.
>
> Bob . . .
>
>
Message 21
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| Subject: | Ground loop risk? |
I'm feeding my strobes from the 12 volt buss behind the panel.
Is it necessary to run the ground for the strobes back to the panel
ground buss, or can I just run the ground to the battery terminal
since I'm in that vicinity?
I'm trying to save a wire going forward.
Will I risk a ground loop if I have more than one ground termination point?
Thanks
Neil
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