Today's Message Index:
----------------------
1. 05:49 AM - Re: NiMH Batteries (Robert L. Nuckolls, III)
2. 06:00 AM - Perplexed by Intercom and radio ground complexities (Ken)
3. 06:00 AM - Re: Charging the battery through the E-bus (Robert L. Nuckolls, III)
4. 07:38 AM - Re: NiMH Batteries (Eric M. Jones)
5. 07:47 AM - Re: LRI Audio Warning Wanted (Robert L. Nuckolls, III)
6. 07:51 AM - Drawing Z-11 (Tom & Carol Strong)
7. 07:51 AM - Re: Perplexed by Intercom and radio ground (Robert L. Nuckolls, III)
8. 08:07 AM - Re: Ground Test???? (Robert L. Nuckolls, III)
9. 08:07 AM - Re: Shoo Goo Repost (Eric M. Jones)
10. 08:16 AM - Re: Clinic in St. Louis and P-Mag call ? (Robert L. Nuckolls, III)
11. 09:16 AM - Re: Contactor vs Power Relay (Eric M. Jones)
12. 09:19 AM - Re: Perplexed by Intercom and radio ground complexities (Bob C.)
13. 09:46 AM - Re: Perplexed by Intercom and radio ground (Robert L. Nuckolls, III)
14. 10:57 AM - Re: Perplexed by Intercom and radio ground complexities (Ken)
15. 11:10 AM - SOT: GPS/NAV Switch (Matthew Brandes)
16. 04:20 PM - Re: Perplexed by Intercom and radio ground (Robert L. Nuckolls, III)
17. 08:12 PM - Automotive wiring harness tape-suitable? (Paul Weismann)
Message 1
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| Subject: | Re: NiMH Batteries |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 05:36 AM 5/30/2005 -0700, you wrote:
>--> AeroElectric-List message posted by: Pat Salvati <pats4p@sbcglobal.net>
>
>Is there any good reason, safety standpoint, that NiMH batteries should
>not be used in an aircraft. I have a dual alternator dual battery ship I'm
>building , NiMH battery packs come in some very attractive packaging
>versus 28v RG battery dimensions. The only one that I have come across is
>the one from B+C (7.5 AH or 11 AH) that would fit for me. Any input would
>be appreciated.
How do you want to use this battery? Which Z-figure are
you considering? The NiMH is not going to be able to help
crank an engine . . . further, it's trickier to charge
than lead-acid and has a 10x higher self-discharge rate
than SVLA batteries.
I think I would recommend that NiMH be limited to portable
power such has handhelds and then if maintained at home in
chargers specific to the characteristics of the cells.
Bob . . .
Message 2
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| Subject: | Perplexed by Intercom and radio ground complexities |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
I am installing a flighttech intercom and an icom radio on a metal panel
and both have dedicated ground wires going to the firewall forest of
tabs. All the ground pins (signal and power) on both devices are common
to their metal cases. But how to connect the two devices together? The
intercom instructions show connecting individual single wires to the mic
and headphone connections on the radio but it seems to make sense to use
shielded cable for this since they run for several inches beside the
electronic ignition and fuel injector wires if I leave a reasonable
length of wire for servicing. Those noisy wires are fairly numerous and
not shielded. So my first inclination is to ground one end only of the
shield. After all it seems that I already have a potential ground loop
going on with the devices grounded together through the panel mounting
screws and through wires going to the firewall. But it doesn't seem
quite right that the mic and headphone grounds go through the firewall
ground if the case grounds become high resistance. Keying the mic adds a
couple of amps to the radio ground wires although they are double runs
of 18awg to keep the voltage drop minimal. I will do it this way unless
someone suggests a better approach.
However the radio instructions show shielded wire for the mic and
headphone with the shield connected at both ends between the radio and
the audio panel. An audio panel is about the same as an intercom on this
aircraft I figure. At first glance this seems better to me with a direct
ground connection between the devices. But it would also give a triple
ground route through 1. the case grounds 2. the shield 3. the wires
from the power ground pins to the firewall. That does not seem like a
good idea.
As always, any thoughts are appreciated
Ken
Message 3
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| Subject: | Re: Charging the battery through the E-bus |
diode
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
diode
At 11:27 AM 5/29/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: "Dave Morris \"BigD\""
><BigD@DaveMorris.com>
>
>Hi Bob,
>
>I'm wiring my plane pretty much according to Z-16, with some minor mods
>since I'm using a coil and points based ignition system on my Corvair
>engine and have implemented an Always-Hot bus.
>
>In studying the schematic and trying to list all possible failures and
>their impact, I began wondering about battery failures. So I have some
>questions. I think these would have to involve in-flight battery failures,
>(let's say one dead cell), so they may be extremely rare, but I wonder still:
>
>1. If you open the battery contactor and close the E-bus switch in flight,
>and the battery needs a lot of charging, the alternator will attempt to do
>so through the E-bus diode, which could presumably blow if the charge
>current is high enough. Will it ever get that high? I've got a B&C heat
>sink on mine.
Only if you leave the alternator ON . . . all of my drawings
insure that the alternator is OFF when the battery contactor is
opened.
>2. I'm using a John Deere (PM) dynamo with a regulator whose supply pin is
>connected to the main bus. The battery fails for some reason. I have a
>big electrolytic cap on the output, so everything is fine and dandy, but
>while trying to diagnose what exactly is happening, let's say I make the
>mistake of pulling the dynamo breaker. I will not be able to reset the
>breaker or do anything else to get the dynamo back online, because there is
>no supply voltage to power the regulator.
If you plan to use the PM alternator breaker for control of this device,
then perhaps you're better advised to connect the PM alternator directly
to the battery like I show for the PM aux alternator in Z-13/8.
>So maybe these are very rare, and could be easily overcome by simply using
>two 17ah batteries instead of a single larger battery. Am I wasting my
>time worrying about these?
That's a judgement call only you can make for yourself. If the potential
for battery failure worries you this much, then perhaps two batteries
are in order. I believe probability of loss of a well maintained battery
is along the same order as loss of a major component of your single
ignition system. With reasonable maintenance, both have been attractive
performers for a host of builders.
I don't think I'd go two 17 a.h. batteries. Your ignition system will
run for hours on a 4 a.h. battery. Just add a second battery per Z-30
except small battery and 30A plastic relay instead of big contactor.
Don't close second battery contactor for cranking . . . in fact, consider
automatic aux battery switching as suggested in
http://aeroelectric.com/articles/lvwarn/9021-620.pdf
Use small battery as primary supply for ignition and main battery
bus as secondary supply.
And arrange for PM altenrator to be disconnected from the main
bus any time the battery contactor is open.
Bob . . .
Message 4
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| Subject: | Re: NiMH Batteries |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr@cox.net>
> The NiMH is not going to be able to help
> crank an engine . . . further, it's trickier to charge
> than lead-acid and has a 10x higher self-discharge rate
> than SVLA batteries.
> I think I would recommend that NiMH be limited to portable
> power such has handhelds and then if maintained at home in
> chargers specific to the characteristics of the cells. Bob . . .
My advice is to go ahead and try it. This is an EXPERIMENTAL list. Just keep
good notes and report back.
>The NiMH is not going to be able to help crank an engine . . .
Data point: Last Saturday I tried to put a Craftsman 6.5 HP lawn mower back
into use. I stripped it down to its essentials and diagnosed the beast. Good
compression pop, some spark (weak?). Plug was okay, getting fresh gasoline,
air filter clean. But I needed to spray gas into it while I turned it over.
Whipped out the socket set and my Makita 14.4V 2.6 amp-hour drill. I knew
this was problematic. The Makita, however, had plenty of power to turn over
the lawnmower engine--and did it every time I asked it to through the span
of a short afternoon. And I haven't had to recharge it yet. (I finally sent
the lawnmower to the lawnmower repair shop....)
>--> AeroElectric-List message posted by: "DonVS" <dsvs@comcast.net>
>Nimh batteries have very low tolerence for vibration. I lost a couple of
rc
>helicopters as a result. I went back to Nicad's and have had no problems.
>Just my 2 cents. Don
I think this may be a fairly random event. There are many high-vibration
applications in battery-powered tools (even hammer-drills) where NiMH do
just fine. I haven't heard of this problem before.
The other post make good points about the limitations and advantages. It is
quite possible to use NiMH power packs from portable drills (or just the
batteries) in your airplane. Biz jets use nicads, and NiMHs are worlds
better. Satellites use NiMHs. Yes, the charging circuitry is different but
you can buy it off-the-shelf.
And even better batteries are coming.
Lithiums have been in the news from burning cellphones....so be careful. As
much as I am in favor of new technology, I am putting a single Optima D51
into my Glastar. This seems to make the most sense for my needs.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
"To avoid criticism do nothing, say nothing, be nothing." -- Elbert Hubbard
Message 5
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| Subject: | Re: LRI Audio Warning Wanted |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 10:41 AM 5/30/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: PeterHunt1@aol.com
>
>I have a Lift Reserve Indicator (LRI) and want to add an audio warning to it.
> Has anyone experimented with a pressure differential switch (the LRI needle
>operates by indicating pressure differential) to actuate a warning tone in
>your headset? The LRI manufacturer has told me for three years he is
>working on
>this. I am tired of waiting for something he is likely not going to develop
>and want to develop something on my own.
>
>Pete - Clearwater, FL
>RV-6, all electric panel
>Getting ready for first flight.
Hey Peter, I heard that your airplane was finally out of the
living room. Great news!
The "hard" part is to accurately and repeatedly sense the
pressure at which you want the warning to sound. This would
probably take some form of solid state pressure transducer
like those found on:
http://dkc3.digikey.com/PDF/T052/1507.pdf
These would be combined with a power supply, precision
comparator and calibration potentiometer to make the
alarm sound at the right place.
Do you plan to conduct a lot of "close tolerance" approaches?
This seems like an expensive feature . . .
Bob . . .
Message 6
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--> AeroElectric-List message posted by: Tom & Carol Strong <tstrong@ida.net>
I am getting ready to wire up my RV 9 using the Z-11 plan 12/02 version.
I just noticed on Bob's web site there is a newer version of Z-11 from 4/05.
Is the 12/02 version using the LR-3 alternator controller no longer
acceptable?
Thanks, Tom Strong
Message 7
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| Subject: | Re: Perplexed by Intercom and radio ground |
complexities
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
complexities
At 09:01 AM 5/31/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>
>I am installing a flighttech intercom and an icom radio on a metal panel
>and both have dedicated ground wires going to the firewall forest of
>tabs. All the ground pins (signal and power) on both devices are common
>to their metal cases. But how to connect the two devices together? The
>intercom instructions show connecting individual single wires to the mic
>and headphone connections on the radio but it seems to make sense to use
>shielded cable for this since they run for several inches beside the
>electronic ignition and fuel injector wires if I leave a reasonable
>length of wire for servicing. Those noisy wires are fairly numerous and
>not shielded. So my first inclination is to ground one end only of the
>shield. After all it seems that I already have a potential ground loop
>going on with the devices grounded together through the panel mounting
>screws and through wires going to the firewall. But it doesn't seem
>quite right that the mic and headphone grounds go through the firewall
>ground if the case grounds become high resistance. Keying the mic adds a
>couple of amps to the radio ground wires although they are double runs
>of 18awg to keep the voltage drop minimal. I will do it this way unless
>someone suggests a better approach.
>
>However the radio instructions show shielded wire for the mic and
>headphone with the shield connected at both ends between the radio and
>the audio panel. An audio panel is about the same as an intercom on this
>aircraft I figure. At first glance this seems better to me with a direct
>ground connection between the devices. But it would also give a triple
>ground route through 1. the case grounds 2. the shield 3. the wires
>from the power ground pins to the firewall. That does not seem like a
>good idea.
>
>As always, any thoughts are appreciated
have you reviewed the new chapter on audio systems in the
'Connection. See:
http://dkc3.digikey.com/PDF/T052/1507.pdf
Suggest you congregate ALL panel grounds locally on the panel
before extending them to the firewall ground bus.
Bob . . .
Message 8
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| Subject: | Re: Ground Test???? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 08:46 AM 5/25/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: "Eric Henson"
><ehenson@teamhorner.com>
>
>Bob, is it possible to test your airframe ground? I hooked my B&C
>grounding strap to the 1/4" bolts on my prop gov boss (Its blanked off,
>not using the governor). I'm suspicious because the boss is removable,
>which means its separated from the accessory case by two gaskets. Does the
>current just run through the steel stud/nut connection?
You're correct with your concerns for adequate ground path when the
terminal sets on top of a gasketed cover! The ground strap terminal
needs to be clamped directly against the crankcase.
Bob . . .
Message 9
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| Subject: | Re: Shoo Goo Repost |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>--> AeroElectric-List message posted by: "John Schroeder"
<jschroeder@perigee.net>
>> I want to add that Gorilla Glue has a lot to recommend it. It has become
>> a favorite of mine, although > it has some quirks. Eric -
>Like, what quirks. We always need ideas as to what sticks to what -
>especially to epoxy-glass.
John, et al:
Gorilla Glue is a polyurethane glue. Its advantages are very low cost
compared to epoxy. Very stable bond after hardening. Reasonably fast
setting. Used for most materials. Waterproof and permanent. No fumes--barely
any smell. It is a one-part adhesive that uses water as a kind of
accelerator--you spray a bit of water onto the surfaces you are gluing. This
speeds up the cure (but I think makes the bond more brittle).
The downsides are that it foams when it cures--so clean cosmetic bondlines
are difficult. And it is difficult to remove from fingers (like superglue).
Epoxy-glass often has a weird surface--adhesion is dependent on surface
prep.
I don't necessarily recommend it for everything, but it's a good glue to
become familiar with.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
"Every conscious act of learning requires the willingness to suffer an
injury to one's self-esteem...."
-Thomas Szasz
Message 10
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| Subject: | Clinic in St. Louis and P-Mag call ? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 09:29 AM 4/20/2005 +0200, you wrote:
>--> AeroElectric-List message posted by:
>
>Bob,
>
>Sobering response - thanks. Since my background in electrical engineering is
>close to nil, I am having to climb up a long incline, which leads me to
>occasional tentative decisions based on the most recent information which
>makes sense to me, hence I see-saw between extremes - over simplification to
>bring me to a level I can master and complexity to meet perceived mission
>requirements.
>
>As for rentals, I'd say that if I were intellectually honest, I would only
>rent an airplane after I've had someone knowledgeable fully check it out,
>but I don't do that - so there is a contradiction between my design
>principles and my behavior. Call it rationalization. When I rent I look at
>the track record of the people I rent from and figure if nothing has
>happened so far, there is little likelihood that something will happen as I
>fly the rental.
>
>So, it seems that Z-11 plus a small alternator which makes it Z-13 (correct
>me if I am wrong) would be the way to go - you suggest a small alternator;
>my question is: small alternator or small generator?
It's almost a certainty that the SD-8 will suffice. This
is a very compact, 8A permanent magnet machine from B&C.
Have you conducted a load analysis on your proposed system?
How do you plan to use this airplane? Night? Long flights
over very unfriendly territory? Extended operations in clouds
with ANY risk of ice?
Bob . . .
Message 11
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| Subject: | Re: Contactor vs Power Relay |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckollsr@cox.net>
>--> AeroElectric-List message posted by: "Mark Sletten"
>Bob and/or other expert,
>What's the difference between the Aeroelectric Connection recommended
>battery contactor and a high-amperage automotive power relay such as
>this: http://www.wiringproducts.com/?target=dept_96.html
>Scroll down a bit and you'll find a Bosch 75AMP power relay. This seem
>ideal to use in lieu of the bulky contactor and all it's associated
>diodes and such. What am I missing?
Hi Mark,
Paul Messinger mentioned this part to me. For some reason the specs are hard
to come by. Maybe someone can find them, but I think the device is just a
slightly upgraded R51 Series 70A design.
In general this device is used for a high current contactor in many vehicle
applications. It would make a great landing light relay even in its smaller
40A version.
But be careful regarding some things--(these data are for the 70A part)
The maximum surge current through the part is only about 120A--for cold
filaments. It will only carry AND break 70A. It would not be useful to start
an engine (but a few in parallel would probably do the job).
Don't use these for a B-line contactor since they will not necessarily break
the connection if the alternator runs away.
The current draw seems to be 1 amp or more. This can add up.
Darned nice part though.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
When choosing between two evils, I always like to try the one I've never
tried before.
--Mae West
Message 12
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| Subject: | Re: Perplexed by Intercom and radio ground complexities |
--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
I betting that's not the right link . . . try:
http://www.aeroelectric.com/articles/Rev11/18Audio_R11.pdf
Regards,
Bob Christensen
RV8 Bldr - SE Iowa
On 5/31/05, Robert L. Nuckolls, III <nuckollsr@cox.net> wrote:
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <
> nuckollsr@cox.net> complexities
>
> At 09:01 AM 5/31/2005 -0400, you wrote:
>
> >--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
> >
> >I am installing a flighttech intercom and an icom radio on a metal panel
> >and both have dedicated ground wires going to the firewall forest of
> >tabs. All the ground pins (signal and power) on both devices are common
> >to their metal cases. But how to connect the two devices together? The
> >intercom instructions show connecting individual single wires to the mic
> >and headphone connections on the radio but it seems to make sense to use
> >shielded cable for this since they run for several inches beside the
> >electronic ignition and fuel injector wires if I leave a reasonable
> >length of wire for servicing. Those noisy wires are fairly numerous and
> >not shielded. So my first inclination is to ground one end only of the
> >shield. After all it seems that I already have a potential ground loop
> >going on with the devices grounded together through the panel mounting
> >screws and through wires going to the firewall. But it doesn't seem
> >quite right that the mic and headphone grounds go through the firewall
> >ground if the case grounds become high resistance. Keying the mic adds a
> >couple of amps to the radio ground wires although they are double runs
> >of 18awg to keep the voltage drop minimal. I will do it this way unless
> >someone suggests a better approach.
> >
> >However the radio instructions show shielded wire for the mic and
> >headphone with the shield connected at both ends between the radio and
> >the audio panel. An audio panel is about the same as an intercom on this
> >aircraft I figure. At first glance this seems better to me with a direct
> >ground connection between the devices. But it would also give a triple
> >ground route through 1. the case grounds 2. the shield 3. the wires
> >from the power ground pins to the firewall. That does not seem like a
> >good idea.
> >
> >As always, any thoughts are appreciated
>
> have you reviewed the new chapter on audio systems in the
> 'Connection. See:
>
> http://dkc3.digikey.com/PDF/T052/1507.pdf
>
> Suggest you congregate ALL panel grounds locally on the panel
> before extending them to the firewall ground bus.
>
> Bob . . .
>
>
Message 13
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| Subject: | Re: Perplexed by Intercom and radio ground |
complexities
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
complexities
Oops . . . thanks Bob!
Bob . . .
At 11:19 AM 5/31/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
>
>I betting that's not the right link . . . try:
>http://www.aeroelectric.com/articles/Rev11/18Audio_R11.pdf
> Regards,
>Bob Christensen
>RV8 Bldr - SE Iowa
Message 14
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| Subject: | Re: Perplexed by Intercom and radio ground complexities |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
OK I got the impression from the new chapter that a panel ground was
just another convenient way of doing it rather than the preferred
method. Sounds like it is preferred so I'll do something similar for the
audio and avionics grounds. I imagined pros and cons (both performance
and installation wise) of both methods but obviously this method
generally works well..
thanks
Ken
Robert L. Nuckolls, III complexities wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
complexities
>
>At 09:01 AM 5/31/2005 -0400, you wrote:
>
>
>
>>--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>>
>>I am installing a flighttech intercom and an icom radio on a metal panel
>>and both have dedicated ground wires going to the firewall forest of
>>tabs. All the ground pins (signal and power) on both devices are common
>>to their metal cases. But how to connect the two devices together? The
>>intercom instructions show connecting individual single wires to the mic
>>and headphone connections on the radio but it seems to make sense to use
>>shielded cable for this since they run for several inches beside the
>>electronic ignition and fuel injector wires if I leave a reasonable
>>length of wire for servicing. Those noisy wires are fairly numerous and
>>not shielded. So my first inclination is to ground one end only of the
>>shield. After all it seems that I already have a potential ground loop
>>going on with the devices grounded together through the panel mounting
>>screws and through wires going to the firewall. But it doesn't seem
>>quite right that the mic and headphone grounds go through the firewall
>>ground if the case grounds become high resistance. Keying the mic adds a
>>couple of amps to the radio ground wires although they are double runs
>>of 18awg to keep the voltage drop minimal. I will do it this way unless
>>someone suggests a better approach.
>>
>>However the radio instructions show shielded wire for the mic and
>>headphone with the shield connected at both ends between the radio and
>>the audio panel. An audio panel is about the same as an intercom on this
>>aircraft I figure. At first glance this seems better to me with a direct
>>ground connection between the devices. But it would also give a triple
>>ground route through 1. the case grounds 2. the shield 3. the wires
>>
>>
>>from the power ground pins to the firewall. That does not seem like a
>
>
>>good idea.
>>
>>As always, any thoughts are appreciated
>>
>>
>
> have you reviewed the new chapter on audio systems in the
> 'Connection. See:
>
> http://dkc3.digikey.com/PDF/T052/1507.pdf
>
> Suggest you congregate ALL panel grounds locally on the panel
> before extending them to the firewall ground bus.
>
> Bob . . .
>
>
Message 15
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| Subject: | SOT: GPS/NAV Switch |
--> AeroElectric-List message posted by: "Matthew Brandes" <matthew@n523rv.com>
(Slightly off-topic... someone have place to get avionics questions
answered?)
I'm trying to figure out what sort of "external switch" I need to use for my
KLN-89B/KX-155/KI-209A installation. The 209A has the relay built in, I just
need some sort of external switch. Do I really need a full-blown annunciator
panel? Can I get by with a toggle switch? A Cessna I recently flew in had a
simple button that illuminated GPS or NAV when pressed. I'd like not to
spend $800+/- for an annunciator I really don't need.
Matthew Brandes,
Van's RV-9A (Electrical/FWF)
#90569
http://www.n523rv.com
EAA Chapter 1329 President
EAA Chapter 868 Web Editor
Message 16
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| Subject: | Re: Perplexed by Intercom and radio ground |
complexities
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
complexities
At 01:55 PM 5/31/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>
>OK I got the impression from the new chapter that a panel ground was
>just another convenient way of doing it rather than the preferred
>method. Sounds like it is preferred so I'll do something similar for the
>audio and avionics grounds. I imagined pros and cons (both performance
>and installation wise) of both methods but obviously this method
>generally works well..
>thanks
>Ken
I got the idea from a visit to Lancair's avionics shop out
in Oregon a couple years ago. They were assembling turn-key
panels and fitted each one with a panel ground block
fabricated from a captive stud terminal strip like:
http://www.aeroelectric.com/Pictures/MVC-698X.JPG
Of course, their ground block was a lot larger and had
many more wires.
We commiserated about it's bulkiness and discussed
several ways to make it more compact and user friendly.
The bussed d-sub was discussed and seemed to make the most
sense.
In the mean time, I've seen several audio distribution
amplifiers that fitted an avionics ground block right into
the rear of the amplifier . . . just a whole connector
dedicated to grounding things on the panel. The audio
system was a good "central" accessory that not only
touched a lot of the radios, it was also the most vulnerable
to ground loop induced noise. It made sense to build this
functionality into that accessory as long as it was in
the stack or at least on the panel with other radios.
This also addresses the need for dealing with multiple
shield grounds which tend also to cluster up around the
audio distribution amplifier.
Hence the development of the panel ground block extension
to the ground system architecture illustrated for the past
ten years in the 'Connection. Note that all the z-figures
now include an extended panel ground block that speaks to
this very issue.
Bob . . .
Message 17
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| Subject: | Automotive wiring harness tape-suitable? |
7.50 BARRACUDA_HEADER_FP56 RBL: Blacklist bl.spamcop
[Blocked - see <http://www.spamcop.net/bl.shtml?64.4.51.220>]
--> AeroElectric-List message posted by: "Paul Weismann" <p_weismann@hotmail.com>
I am following the standards of AC43-13B in my use of metal supports to
prevent excess bending or stress of wire bundles. However, in certain
areas, I am thinking of using standard automotive wiring harness tape as a
way to neaten things up and add an additional layer of protection and
support.
For example, I am building a Rotorway helicopter, and there are
approximately 15 wires running down it (not including antenna coax) for
various devices along its length (about 11 feet). I wrapped this bundle in
tape to see how it worked and it seems to make the bundle quite sturdy
(although I have metal standoffs every 12-18 inches in the boom).
Of course, adding wires to such a bundle would be a major PITA, so I stuck
another 2 conductors through it for spares. Any other issues or problems
with this setup?
Thanks
Paul
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