Today's Message Index:
----------------------
1. 07:56 AM - Re: Contactor Locations (Robert L. Nuckolls, III)
2. 08:30 AM - Z-14 add the RV6A (or 7A) ???? (James E. Clark)
3. 09:29 AM - Re: De-Rate Mini Switches? (Robert L. Nuckolls, III)
4. 09:51 AM - Re: De-Rate Mini Switches? (Robert L. Nuckolls, III)
5. 10:11 AM - Re: De-Rate Mini Switches? ()
6. 10:17 AM - Re: De-Rate Mini Switches? (N67BT@aol.com)
7. 10:20 AM - Re: De-Rate Mini Switches? (Aucountry@aol.com)
8. 10:37 AM - Re: De-Rate Mini Switches? (Robert L. Nuckolls, III)
9. 10:38 AM - Re: De-Rate Mini Switches? (Robert L. Nuckolls, III)
10. 10:41 AM - Radio Wiring question (Vince Ackerman)
11. 10:42 AM - Re: De-Rate Mini Switches? (RSwanson)
12. 10:57 AM - Re: System architecture decisions (Robert L. Nuckolls, III)
13. 11:03 AM - Re: Z-14 add the RV6A (or 7A) ???? (Robert L. Nuckolls, III)
14. 11:09 AM - Re: De-Rate Mini Switches? (Richard E. Tasker)
15. 11:22 AM - Re: fast on connectors (Robert L. Nuckolls, III)
16. 11:39 AM - Re: Radio Wiring question (Charlie & Tupper England)
17. 12:39 PM - Re: Alternator Alternatives? (Robert L. Nuckolls, III)
18. 12:42 PM - Re: Wing-Tip VOR Antenna (Robert L. Nuckolls, III)
19. 01:00 PM - Re: De-Rate Mini Switches? (Tinnemaha)
20. 03:26 PM - Re: Radio Wiring question (Vince Ackerman)
21. 03:50 PM - Re: Z-14 AND the RV6A (or 7A) ???? (James E. Clark)
22. 03:50 PM - Shop Light Interference with Radio (John H. Wiegenstein)
23. 04:25 PM - Re: Z-14 AND the RV6A (or 7A) ???? (Jim Pack)
24. 04:33 PM - Re: Shop Light Interference with Radio (Terry Watson)
25. 05:39 PM - Re: Shop Light Interference with Radio (N67BT@aol.com)
26. 06:17 PM - Re: Radio Wiring question (Leonard Garceau)
27. 06:31 PM - Re: De-Rate Mini Switches? (Richard E. Tasker)
28. 06:50 PM - Re: Shop Light Interference with Radio (Robert L. Nuckolls, III)
29. 08:13 PM - Re: Z-14 AND the RV6A (or 7A) ???? (James E. Clark)
30. 08:44 PM - Re: De-Rate Mini Switches? (Robert L. Nuckolls, III)
31. 10:06 PM - Re: Z-14 AND the RV6A (or 7A) ???? (Jim Pack)
32. 10:40 PM - Wire bundles through firewall . . . (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Contactor Locations |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:47 PM 3/1/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "William Bernard"
><billbernard@worldnet.att.net>
>
>First, Thanks for the responses on the heat sink for the diode. I don't
>believe that the e-bus loads will be 10 amps, but I thought it would give
>me some safety factor since nothing is actually wired yet.
>
>The nest question I have is to see if there are any problems with where I
>plan to physically locate the various contactors in the aircraft. (The
>aircraft is a Wittman Tailwind.) The battery is behind the seat and the
>battery contactor (and battery bus) will mount near the battery. There
>will be a 2AWG wire running to the starter contactor. I'm planning to
>locate the starter contactor on the engine side of the firewall, about 5
>feet from the battery. The b-lead from the alternator will run back to the
>battery side of the starter contactor. The ground power plug will also
>connect to the battery side of the starter contactor. The ground power
>plug will be located on the firewall and accessed through a hole in the cowl.
Many production aircraft connect ground power as you have
described. I favor the wiring shown in
http://www.aeroelectric.com/articles/grndpwr.pdf
for several reasons.
Ground power cannot be applied to your aircraft without
also having ship's battery across the supply . . . batteries
are strong filters and reasonable mitigators of poor power
quality.
Ground power tied right to the battery can be used to charge
the battery where it sits in the airplane without having
to power up the whole airplane.
In your case, the line mechanic will appreciate it if
your ground power jack is further away from the prop.
>Are there any major problems with locating things where indicated? Also,
>is there any need to protect the battery side of the starter contactor
>from the possibility of an arc to the firewall? The terminal, with three
>pretty big wires on it, will be about an inch away from the firewall
>(stainless steel). I haven't seen any of the little rubber boots that
>would accomodate 3 wires like this.
How are these wires going to "get loose" and/or what articles
of equipment located nearby are likely to come into contact
with the terminal? If there are candidate conditions that
put the system at risk, it's usually easier and better
design to eliminate them as opposed to guarding against
them. The bus bars on production aircraft are good examples.
They are large areas of un-insulated, high current conductors
that are waving out there in the breeze . . . but with no
concerns because of their construction integrity and controlled
environment. It's akin to operating your airplane in a way
that eliminates the need for guards around your propeller
to keep body parts out of them.
The soft rubber, insulating booties found on many fat-wire
terminals may be useful for keeping the band of your wrist
watch from coming into contact with a hot terminal . . . but
that's about all. They have no structural integrity and
should not be depended upon to "protect" your system
from the results of poor planning and/or mechanical
design.
Bob . . .
>Thanks again for the help.
>
>Bill
>
>
Bob . . .
|-------------------------------------------------------|
| The man who does not read good books has no advantage |
| over the man who cannot read them. |
| - Mark Twain |
|-------------------------------------------------------|
Message 2
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| Subject: | Z-14 add the RV6A (or 7A) ???? |
--> AeroElectric-List message posted by: "James E. Clark" <jclark@conterra.com>
GlacierI am now working on an RV6A that I plan to make "all electric" per
Z-14.
Has anyone out there on the list implemented Bob's "Z-14" (dual battery/dual
alternator) on the RV6/7A???
If so I have a few questions:
1. Which batteries did you use? (Bill of B&C recommends 2 of their 12AH
batteries ... fine by me)
2. Did you mount your batteries inside the cabin or on the firewall?
3. If you mounted them on the firewall (where I wish to), how did you do it
... one per side? Both on same side?
4. What about the mounting of the contactors?
5. If you mounteed them one per side, how was the wire run for
"interconnect" handled?
Part of the problem I seem to be having is that I do not see how I can mount
the two batteries on the same side and I have not been able to find
batteries that are both suitable and much smaller.
Any advice (and especially pictures) would be appreciated before I go and
re-invent the wheel.
Thanks in advance.
James
p.s. The RV6 that my partner and I built and are flying, has the single
battery (PC680) mounted on the firewall and all if fine ... so I am a little
bit familiar with some of the issues.
"If you don't make dust, you eat dust"
Message 3
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:57 PM 3/1/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Tinnemaha" <Tinnemaha@charter.net>
>
>Hello List,
>
>This is my first post. I am building a 12 Volt system and want to
>incorporate Alco Ultra-Mini Toggle switches wherever possible but I need
>advice:
>
>The catalog says the switches are rated for 6 amps at 125 V AC and 4 amps
>at 28 V DC: Can I assume they are rated for 8 amps at 14 V?
>
>AC 43-13 requires de-rating factors to be applied to switches (factors
>vary according to voltage & type of load): Do you apply the same de-rating
>factors?
Be wary of AC43-13 and in particular any sense you may
have that what's offered is in any way a REQUIREMENT for
you as the builder of an airplane. AC43-13 contains some
really good information but it's rife with little pockets
of junk science and outright errors.
Everything AC43-13 purports to do for system reliability
is ALWAYS predicated on increasing longevity through
quality enhancement, little tricks-of-the-trade like de-rating
certain parts, and a reverence for things "certified" for both
hardware and the people who are allowed to work on airplanes.
No place in AC43-13 or any other holy-watered document will
you see a discussion of architecture that produces system
reliability by way of a failure tolerant design.
Take peek at the article on switch ratings at:
http://www.aeroelectric.com/articles/swtchrat.pdf
I wouldn't discourage you from your quest to build
with small switches but keep in mind the following
considerations as physical size goes down in a switch.
(1) assuming most switches have about the same on-resistance,
smaller switches will run warmer at the same current levels
thus exacerbating degradation of contacts during the ON times.
Loads like landing lights and pitot heaters are best handled
by a relay (like S704-1 on our website) which is in turn
controlled by a miniature switch.
(2) if you have magnetos and choose to be rid of the
Jurassic key-switch, then be aware of voltage breakdown
limitations on the small switches in their OPEN position.
I would be wary of a miniature toggle switch's ability
to stand off the several hundred, fast rate-of-rise volts
that are present on p-leads of a mag. After some
years in service, a miniature switch may acquire enough
contaminates to be vulnerable to this kind of stress even
though it worked fine upon initial installation. The result
would be a rough running mag that is being sapped of
spark energy by arcing at the switch. If you're
contemplating electronic ignition, this isn't a concern.
Choose good quality switches. Brands like C&K or
Cuttler-Hammer and ALCO are mechanically more robust
than miniature switches of unknown pedigree found
in many parts catalogs.
Finally, plan ahead. Should you find at some time
in the future that your choice of switches produced
less than satisfactory performance, will surgery
to your panel be a major or minor effort?
Bob . . .
Message 4
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:16 PM 3/1/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Richard E. Tasker"
><retasker@optonline.net>
>
>No, the rating at 14V would be essentially the same as 28V. The switch
>ratings are based on two factors: the steady state current handling
>capacity of the contacts and, when switched from on to off, the ability
>to break the current carried by the switch and quench the internal arc
>caused by opening the switch contacts.
>
>The ratings you quote indicate that the physical current handling
>capacity is 6 amps steady state - which limits the 125VAC rating. The
>reason the DC rating is less is due to the second limitation. With AC,
>the current goes through zero 120 times per second,which serves very
>nicely to quench the arc when switching a load off. With DC, the
>current is continuous so the contacts have to open wide enough to cause
>the internal arc to quench.
>
>Bottom line - do not use this switch for more than 4A continuous at 14 VDC.
>
>Dick Tasker
Good answer . . . I agree.
Bob . . .
Message 5
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: <315@cox.net>
Hi Bob,
I am thinking through rewiring my RV6A. It has a Chevy V6 engine which has
an older style ignition system. A dual point distributer and dual coils
provide one backup to the spark plugs thru a coil selector. Current is
passed thru a ballast resistor before entering the coils.
I would like to provide power supply redundancy that would deal with either
a shorted out battery or a loss of an alternator. I recently had a battery
short causing an OV and the panel 60 amp breaker to pop. I also recently
had an alternator OV and try to fry the battery.
I have been studying the "the book" and am wondering how to configure the
most reliable, simple system. I am thinking of replacing the vacuum pump
with a PM Alternator along the lines of Z-13 or possibly Z-14. I am looking
to find a PM alternator that will run without the battery so it can feed the
ignition system independantly. I am thinking that I would like to
incorporate Z-29 or Z-30 to keep the ignition circuit always hot but can't
quite see how to isolate the battery from the ignition in the event of the
battery shorting.
Any comments appreciated.
Thanks,
Ned
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: De-Rate Mini Switches?
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 06:57 PM 3/1/2003 -0800, you wrote:
> >--> AeroElectric-List message posted by: "Tinnemaha"
<Tinnemaha@charter.net>
> >
> >Hello List,
> >
> >This is my first post. I am building a 12 Volt system and want to
> >incorporate Alco Ultra-Mini Toggle switches wherever possible but I need
> >advice:
> >
> >The catalog says the switches are rated for 6 amps at 125 V AC and 4 amps
> >at 28 V DC: Can I assume they are rated for 8 amps at 14 V?
> >
> >AC 43-13 requires de-rating factors to be applied to switches (factors
> >vary according to voltage & type of load): Do you apply the same
de-rating
> >factors?
>
> Be wary of AC43-13 and in particular any sense you may
> have that what's offered is in any way a REQUIREMENT for
> you as the builder of an airplane. AC43-13 contains some
> really good information but it's rife with little pockets
> of junk science and outright errors.
>
> Everything AC43-13 purports to do for system reliability
> is ALWAYS predicated on increasing longevity through
> quality enhancement, little tricks-of-the-trade like de-rating
> certain parts, and a reverence for things "certified" for both
> hardware and the people who are allowed to work on airplanes.
>
> No place in AC43-13 or any other holy-watered document will
> you see a discussion of architecture that produces system
> reliability by way of a failure tolerant design.
>
> Take peek at the article on switch ratings at:
> http://www.aeroelectric.com/articles/swtchrat.pdf
>
> I wouldn't discourage you from your quest to build
> with small switches but keep in mind the following
> considerations as physical size goes down in a switch.
>
> (1) assuming most switches have about the same on-resistance,
> smaller switches will run warmer at the same current levels
> thus exacerbating degradation of contacts during the ON times.
> Loads like landing lights and pitot heaters are best handled
> by a relay (like S704-1 on our website) which is in turn
> controlled by a miniature switch.
>
> (2) if you have magnetos and choose to be rid of the
> Jurassic key-switch, then be aware of voltage breakdown
> limitations on the small switches in their OPEN position.
> I would be wary of a miniature toggle switch's ability
> to stand off the several hundred, fast rate-of-rise volts
> that are present on p-leads of a mag. After some
> years in service, a miniature switch may acquire enough
> contaminates to be vulnerable to this kind of stress even
> though it worked fine upon initial installation. The result
> would be a rough running mag that is being sapped of
> spark energy by arcing at the switch. If you're
> contemplating electronic ignition, this isn't a concern.
>
> Choose good quality switches. Brands like C&K or
> Cuttler-Hammer and ALCO are mechanically more robust
> than miniature switches of unknown pedigree found
> in many parts catalogs.
>
> Finally, plan ahead. Should you find at some time
> in the future that your choice of switches produced
> less than satisfactory performance, will surgery
> to your panel be a major or minor effort?
>
> Bob . . .
>
>
Message 6
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: N67BT@aol.com
Bob,
Will the S704-1 relay work for an Infinity grip starter switch setup?
> Loads like landing lights and pitot heaters are best handled
> by a relay (like S704-1 on our website) which is in turn
> controlled by a miniature switch.
Thanks,
Bob Trumpfheller
Building a RV7A QB in Western Colorado
Message 7
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: Aucountry@aol.com
In a message dated 03/02/03 09:51:49 AM, bob.nuckolls@cox.net writes:
> >The ratings you quote indicate that the physical current handling
> >capacity is 6 amps steady state - which limits the 125VAC rating.=A0 The
> >reason the DC rating is less is due to the second limitation.=A0 With AC,
> >the current goes through zero 120 times per second,which serves very
> >nicely to quench the arc when switching a load off.=A0 With DC, the
> >current is continuous so the contacts have to open wide enough to cause
> >the internal arc to quench.
> >
>
What about putting a diode across the contacts? Would that help with the
transients? How would this diode be attached?
Gary
Message 8
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:19 PM 3/2/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: Aucountry@aol.com
>
>
>In a message dated 03/02/03 09:51:49 AM, bob.nuckolls@cox.net writes:
>
>
> > >The ratings you quote indicate that the physical current handling
> > >capacity is 6 amps steady state - which limits the 125VAC rating.=A0 The
> > >reason the DC rating is less is due to the second limitation.=A0 With AC,
> > >the current goes through zero 120 times per second,which serves very
> > >nicely to quench the arc when switching a load off.=A0 With DC, the
> > >current is continuous so the contacts have to open wide enough to cause
> > >the internal arc to quench.
> > >
> >
>
>What about putting a diode across the contacts? Would that help with the
>transients? How would this diode be attached?
>
>Gary
No help here. It's not a 'transient' . . . when contacts FIRST
open, the air gap is measured in nano-inches . . . any voltage
level will form an arc in this gap. The secret is to increase
contact mass (to take heat out) and increase spreading velocity
(to stretch arc so fast it doesn't have time to heat things up)
and increase air gap for opened switch. All of these things
are physically limited when you miniaturize a switch.
Bob . . .
Message 9
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:16 PM 3/2/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: N67BT@aol.com
>
>Bob,
>
>Will the S704-1 relay work for an Infinity grip starter switch setup?
sure. relays can be used to boost the current handling
ability of any switching device. That's what starter and
battery contactors do too. You wouldn't want to put 200+
amp rated switches on your control panel for these tasks.
Bob . . .
Message 10
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| Subject: | Radio Wiring question |
--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
I'm a total novice so forgive me for the dumb questions. I can't get
any tech support on weekends so I thought I'd ask here first.
I'm trying to connect a DRE 244e intercom to a Garmin 250xl gps/com.
The 250xl has the com wires coming from the rack labeled as follows:
Each is a two wire twisted pair with shield
1st bundle
Mic Audio Hi - white
Mic Audio Key - blue/white (is this the PTT?)
Mic Audio low - shield
2nd bundle
Com Audio Hi - white
Com Audio Low - blue/white
Not labeled - shield (present but not labeled)
The DRE 244e diagram shows a RAD cable from intercom connected to a
radio as follows:
green wire -- Earphone
red wire -- Mic
white wire -- PTT
black and shield wire -- Gnd
I'm not sure how to go about wiring this up. What does low/high on the
250xl mean? Is low the ground in the reference to DRE 244e diagram?
The unlabeled shield on the com audio should be connected to what?
Could anyone give me some help?
Also, I need to make the instrument/ radio panel removable. Can I use
molex type connectors between the radio rack wiring and the DRE 244?
Will this cause interference/noise problems?
I also have two PTT switch's located on my stick grips . The DRE 244e
diagram shows these as wired off of the Pilot and Copilot headset wire
bundles on the intercom, from each black wire (looks like it's the
upper contact on the mike jack) and ground (shield) wire that run to
the mic/headphone jacks. Rather than running another set of wires from
the jacks, Can I intercept/splice into these wires closer to the
intercom unit without worrying about inducing some sort of noise
problems. They pass right next to the sticks. Also, Do the wires to
the stick grips need to be twisted pair?
Hope this is clear enough to figure out what I'm struggling with.
Thanks for your assistance
George Ackerman
Message 11
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: RSwanson <rswan19@comcast.net>
You might look at the Shogun alternator. It's rated at 15 amps, super
simple and very small. I know of several people who run them on their
racecars and have seen at least one airplane using one.
R
http://www.shogunindustries.com/cgi-local/Web_store/ws400CS.cgi
----- Original Message -----
From: <315@cox.net>
Subject: Re: AeroElectric-List: De-Rate Mini Switches?
> --> AeroElectric-List message posted by: <315@cox.net>
>
> Hi Bob,
>
> I am thinking through rewiring my RV6A. It has a Chevy V6 engine which
has
> an older style ignition system. A dual point distributer and dual coils
> provide one backup to the spark plugs thru a coil selector. Current is
> passed thru a ballast resistor before entering the coils.
>
> I would like to provide power supply redundancy that would deal with
either
> a shorted out battery or a loss of an alternator. I recently had a
battery
> short causing an OV and the panel 60 amp breaker to pop. I also recently
> had an alternator OV and try to fry the battery.
>
> I have been studying the "the book" and am wondering how to configure the
> most reliable, simple system. I am thinking of replacing the vacuum pump
> with a PM Alternator along the lines of Z-13 or possibly Z-14. I am
looking
> to find a PM alternator that will run without the battery so it can feed
the
> ignition system independantly. I am thinking that I would like to
> incorporate Z-29 or Z-30 to keep the ignition circuit always hot but
can't
> quite see how to isolate the battery from the ignition in the event of
the
> battery shorting.
>
> Any comments appreciated.
>
> Thanks,
> Ned
>
>
> ----- Original Message -----
> From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
> To: <aeroelectric-list@matronics.com>
> Subject: Re: AeroElectric-List: De-Rate Mini Switches?
>
>
> > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <bob.nuckolls@cox.net>
> >
> > At 06:57 PM 3/1/2003 -0800, you wrote:
> > >--> AeroElectric-List message posted by: "Tinnemaha"
> <Tinnemaha@charter.net>
> > >
> > >Hello List,
> > >
> > >This is my first post. I am building a 12 Volt system and want to
> > >incorporate Alco Ultra-Mini Toggle switches wherever possible but I
need
> > >advice:
> > >
> > >The catalog says the switches are rated for 6 amps at 125 V AC and 4
amps
> > >at 28 V DC: Can I assume they are rated for 8 amps at 14 V?
> > >
> > >AC 43-13 requires de-rating factors to be applied to switches (factors
> > >vary according to voltage & type of load): Do you apply the same
> de-rating
> > >factors?
> >
> > Be wary of AC43-13 and in particular any sense you may
> > have that what's offered is in any way a REQUIREMENT for
> > you as the builder of an airplane. AC43-13 contains some
> > really good information but it's rife with little pockets
> > of junk science and outright errors.
> >
> > Everything AC43-13 purports to do for system reliability
> > is ALWAYS predicated on increasing longevity through
> > quality enhancement, little tricks-of-the-trade like de-rating
> > certain parts, and a reverence for things "certified" for both
> > hardware and the people who are allowed to work on airplanes.
> >
> > No place in AC43-13 or any other holy-watered document will
> > you see a discussion of architecture that produces system
> > reliability by way of a failure tolerant design.
> >
> > Take peek at the article on switch ratings at:
> > http://www.aeroelectric.com/articles/swtchrat.pdf
> >
> > I wouldn't discourage you from your quest to build
> > with small switches but keep in mind the following
> > considerations as physical size goes down in a switch.
> >
> > (1) assuming most switches have about the same on-resistance,
> > smaller switches will run warmer at the same current levels
> > thus exacerbating degradation of contacts during the ON times.
> > Loads like landing lights and pitot heaters are best handled
> > by a relay (like S704-1 on our website) which is in turn
> > controlled by a miniature switch.
> >
> > (2) if you have magnetos and choose to be rid of the
> > Jurassic key-switch, then be aware of voltage breakdown
> > limitations on the small switches in their OPEN position.
> > I would be wary of a miniature toggle switch's ability
> > to stand off the several hundred, fast rate-of-rise volts
> > that are present on p-leads of a mag. After some
> > years in service, a miniature switch may acquire enough
> > contaminates to be vulnerable to this kind of stress even
> > though it worked fine upon initial installation. The result
> > would be a rough running mag that is being sapped of
> > spark energy by arcing at the switch. If you're
> > contemplating electronic ignition, this isn't a concern.
> >
> > Choose good quality switches. Brands like C&K or
> > Cuttler-Hammer and ALCO are mechanically more robust
> > than miniature switches of unknown pedigree found
> > in many parts catalogs.
> >
> > Finally, plan ahead. Should you find at some time
> > in the future that your choice of switches produced
> > less than satisfactory performance, will surgery
> > to your panel be a major or minor effort?
> >
> > Bob . . .
> >
> >
>
>
Message 12
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| Subject: | Re: System architecture decisions |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:11 PM 3/2/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: <315@cox.net>
>
>Hi Bob,
>
>I am thinking through rewiring my RV6A. It has a Chevy V6 engine which has
>an older style ignition system. A dual point distributer and dual coils
>provide one backup to the spark plugs thru a coil selector. Current is
>passed thru a ballast resistor before entering the coils.
>
>I would like to provide power supply redundancy that would deal with either
>a shorted out battery or a loss of an alternator. I recently had a battery
>short causing an OV and the panel 60 amp breaker to pop.
I am having trouble figuring out what kind of failure
would produce the symptoms (breakers opening) that you
describe. A shorted battery wouldn't produce these
effects . . . and if you had an RG battery installed,
likelihood of shorting goes down to very small orders
of probability.
> I also recently
>had an alternator OV and try to fry the battery.
Did you have any kind of ov protection installed? If so, then the
ov protection device should have done its job and shut down the
failed alternator system. After that, assuming you've done
your homework for calculating and supporting endurance loads,
your battery should have been ready, willing and able to put
you on the ground comfortably.
>I have been studying the "the book" and am wondering how to configure the
>most reliable, simple system. I am thinking of replacing the vacuum pump
>with a PM Alternator along the lines of Z-13 or possibly Z-14. I am looking
>to find a PM alternator that will run without the battery so it can feed the
>ignition system independantly. I am thinking that I would like to
>incorporate Z-29 or Z-30 to keep the ignition circuit always hot but can't
>quite see how to isolate the battery from the ignition in the event of the
>battery shorting.
RG batteries don't short. Maintained flooded batteries
don't short. If you conduct event he most relaxed protocols
of preventative maintenance on your airplane, the battery
is an extremely reliable source of energy. You'll be replacing
the battery long before its quality degrades to the
conditions characteristic of shorted cells in flooded
batteries.
The automotive coil and distributor ignition system is
also very reliable . . . aside from wires breaking off
(easy to control with good craftsmanship and periodic
inspection) these systems seldom fail catastrophic
and with easy. low cost preventative maintenance, they
don't wear out and get flaky either.
I would agree that in light of your cited experiences,
some attention to power generation reliability is in
order. Your selection of alternator, regulator and
ov protection can go a long way toward preventing
recurrent experiences. All-electric is another good
option to consider. But I'll suggest that if you drive
your ignition directly from a well maintained RG battery
and provide backup to the main alternator as shown
in Z-13, your system will be quite reliable with no
further concerns for keeping the ignition coil
happily fed with electrons.
Bob . . .
Message 13
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| Subject: | Re: Z-14 add the RV6A (or 7A) ???? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:29 AM 3/2/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "James E. Clark"
><jclark@conterra.com>
>
>GlacierI am now working on an RV6A that I plan to make "all electric" per
>Z-14.
>
>Has anyone out there on the list implemented Bob's "Z-14" (dual battery/dual
>alternator) on the RV6/7A???
>
>If so I have a few questions:
>
>1. Which batteries did you use? (Bill of B&C recommends 2 of their 12AH
>batteries ... fine by me)
>2. Did you mount your batteries inside the cabin or on the firewall?
>3. If you mounted them on the firewall (where I wish to), how did you do it
>... one per side? Both on same side?
>4. What about the mounting of the contactors?
>5. If you mounteed them one per side, how was the wire run for
>"interconnect" handled?
>
>Part of the problem I seem to be having is that I do not see how I can mount
>the two batteries on the same side and I have not been able to find
>batteries that are both suitable and much smaller.
>
>
>Any advice (and especially pictures) would be appreciated before I go and
>re-invent the wheel.
As I recall, Van's plans call for a 24 a.h. battery
on centerline, just behind the firewall. Given that
a pair of 12 a.h. batteries has about the same footprint
as a single 24 a.h. battery, could they not be mounted
side-by-side in the same place as a 24 a.h. battery?
Bob . . .
Message 14
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
>
>
>What about putting a diode across the contacts? Would that help with the
>transients? How would this diode be attached?
>
Alas, that will not help. The arc across the switch is caused by
current flowing in the normal direction. A diode would not do anything
since if it was placed on the switch to absorb/shunt the current it
would allow whatever the switch was switching to be on all the time. If
it was placed on the switch in the reverse manner, it would not do anything.
When switching resistive loads (lights, instruments, etc.) any internal
arc is just caused by the physical act of opening the contacts. As the
contacts go from closed to fully open, the space between them increases.
At first, when the space is infinitesimal, the current continues to
flow as a plasma is created between the contacts. This continues until
the spacing is large enough that the plasma breaks down and the circuit
opens. The larger the current flow, the greater the space required to
quench the plasma (think electrical arc welding on a miniature scale).
However, unlike inductive loads (coils, relays, etc.), there is no
energy storage that will increase the voltage as the circuit opens - so
if the manufacturer does his design job correctly and rates the switch
properly, you can expect a long and useful life from the switch (if you
use it within its ratings).
A diode MUST be placed across any coils or relays that are switched (see
numerous descriptions and comments on this in Aeroelectric Connection,
et. al.) to prevent damage to the device doing the switching. This
protects the switch from transients caused by the relay/coil by
eliminating or minimizing the transient in the first place. Without
this protection, the switch will fail quite quickly (and probably just
when you need it to work properly :-) ).
The switch ratings noted in the previous discussion are real and cannot
be improved upon (except by the manufacturer). You can, however,
effectively reduce the ratings and destroy the switch very quickly by
not doing anything to eliminate switching transients.
Dick Tasker
Message 15
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| Subject: | Re: fast on connectors |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:20 AM 3/1/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: DHPHKH@aol.com
>
><<hardware store terminals>>
>
> Gee Bob, you really know how to hurt a guy <g>
>
> My comments were directed to the concept of using quality heat
> shrink as
>a method of terminal insulation and prevention of wire fatigue. It also
>looks better than squashed nylon and requires less physical space. The
>trade-off is some additional time investment. I'm not running a production
>line.
>
<snip>
> I fully agree that you should not use substitutes without due
> dilligence,
>including simple tests in your own shop.
>
> Old buddy, I ain't trying to teach you how to suck eggs. It's just an
>alternate method.
Understand my friend . . . and no offense intended. I'm just
trying to reason through the value of adopting an alternative
technology. Aside from the savings in "physical space", how
do we gain by adopting an second technology requiring
yet another tool to install a more labor-and-materials
intensive substitute for the first choice which uses tools
we may already have? I suppose one could decide to go non-PIDG
throughout the project and opt instead to purchase tools that
apply only un-insulated terminals.
Bob . . .
Message 16
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| Subject: | Re: Radio Wiring question |
--> AeroElectric-List message posted by: Charlie & Tupper England <cengland@netdoor.com>
Partial answers below:
Vince Ackerman wrote:
>--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
>
>I'm a total novice so forgive me for the dumb questions. I can't get
>any tech support on weekends so I thought I'd ask here first.
>
>I'm trying to connect a DRE 244e intercom to a Garmin 250xl gps/com.
>The 250xl has the com wires coming from the rack labeled as follows:
>
>Each is a two wire twisted pair with shield
>
>1st bundle
>Mic Audio Hi - white
>Mic Audio Key - blue/white (is this the PTT?)
>Mic Audio low - shield
>
>2nd bundle
>Com Audio Hi - white
>Com Audio Low - blue/white
> Not labeled - shield (present but not labeled)
>
>The DRE 244e diagram shows a RAD cable from intercom connected to a
>radio as follows:
>
>green wire -- Earphone
>red wire -- Mic
>white wire -- PTT
>black and shield wire -- Gnd
>
1st bundle
Mic Audio Hi - white <from< DRE red
Mic Audio Key - blue/white (is this the PTT?yes) <from< DRE white
Mic Audio low - shield <from< DRE sheild
2nd bundle
Com Audio Hi - white >> to >> DRE green
Com Audio Low - blue/white >> to >> DRE black
Not labeled - shield (present but not labeled)
>
>I'm not sure how to go about wiring this up. What does low/high on the
>250xl mean? Is low the ground in the reference to DRE 244e diagram?
>The unlabeled shield on the com audio should be connected to what?
>Could anyone give me some help?
>
Hi usually means audio; low usually means audio return or audio ground.
Look at the radio's hookup diagram & be sure they aren't sending the
'high' to a speaker & the 'low' to the headphones.
Audio 'grounds' are usually kept isolated from the airframe to prevent
'ground loops', or noise in the audio circuits.
Hard to say about the unlabeled shield; it could be intended to provide
noise shielding for the audio output wires & left floating at the other end.
>
>Also, I need to make the instrument/ radio panel removable. Can I use
>molex type connectors between the radio rack wiring and the DRE 244?
>Will this cause interference/noise problems?
>
Unlikely to cause problems, but each install is different.
>
>I also have two PTT switch's located on my stick grips . The DRE 244e
>diagram shows these as wired off of the Pilot and Copilot headset wire
>bundles on the intercom, from each black wire (looks like it's the
>upper contact on the mike jack) and ground (shield) wire that run to
>the mic/headphone jacks. Rather than running another set of wires from
>the jacks, Can I intercept/splice into these wires closer to the
>intercom unit without worrying about inducing some sort of noise
>problems. They pass right next to the sticks. Also, Do the wires to
>the stick grips need to be twisted pair?
>
Many intercoms are designed to allow the pilot's PTT & mic audio to
override the passenger's. This would mean running the wires as shown in
the DRE diagram to preserve the 'priority' feature. Does the DRE's
manual mention this feature?
Twisted pair is probably good enough for the PTT switches, but if you've
got the wire for the mic/PTT/sheild lines anyway, why not use it? The
PTT ties the white to shield when pushed (closed).
Charlie
>
>Hope this is clear enough to figure out what I'm struggling with.
>
>Thanks for your assistance
>
>George Ackerman
>
Message 17
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| Subject: | Re: Alternator Alternatives? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:41 PM 3/2/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: RSwanson <rswan19@comcast.net>
>
>You might look at the Shogun alternator. It's rated at 15 amps, super
>simple and very small. I know of several people who run them on their
>racecars and have seen at least one airplane using one.
>R
>http://www.shogunindustries.com/cgi-local/Web_store/ws400CS.cgi
This appears to be an adaptation of the PM alternator
common to many garden tractors a-la Kubota, etc. If
you can belt drive a second alternator, you might
want to look at spare parts for tractors.
Bob . . .
Message 18
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| Subject: | Wing-Tip VOR Antenna |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:00 PM 3/1/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Carl Froehlich" <carlfro@erols.com>
>
>Larry - the short strip of aluminum is not the antenna - it is part of the
>gamma match. The gamma match is an impedance transform network to match the
>impedance of the antenna to the feed line.
>Note RF is very much different than DC. This antenna is at DC ground
>potential, but certainly not grounded for RF. Unless you can find yourself
>a local amateur radio operator (that has been around the block a few times)
>to walk you through this just copy the drawing exactly.
>I am using a much modified wing tip antenna for my comm radio and am quite
>please with its performance- but I have been playing with antennas for 30
>years and have the necessary test equipment to make them work.
>
>Carl Froehlich
>RV-8A (flying)
>Vienna, VA
Thanks for fielding this one Carl . . .
Bob . . .
Message 19
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Tinnemaha" <Tinnemaha@charter.net>
Thank You Richard,
I will not put more than 4 Amps on one of these switches even in my 14 V system.
Can you tell me if higher rated mini switches are available? Where?
What about the de-rating of switches mentioned in AC 43-13? Do you follow that
or is it too conservative?
Grant
Message 20
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| Subject: | Re: Radio Wiring question |
--> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
Charlie
Thanks for the info!
The wiring diagram for the 250xl comm shows the 2 Comm audio leads
coming out as a hi and low, both going to an "audio panel." It doesn't
really specify what goes to what. It also shows the shield wire, with a
note to ground the shield at the audio panel. On the shield end of the
250xl, the diagram indicates that the shield doesn't appear to be
connected to anything, unlike other shields such as the Mic. Should I
assume the shield for the comm goes to ground with the rest (the black
and shield wires on the DRE)? It's a little confusing how this works.
The DRE does override the passenger audio. Both wire bundles for the
Pilot and Pax go past the control sticks so instead of running wires
back from the jacks by the headrests I was just going to splice into
the bundles near each stick to go to the PTT 's on the grips.
Thanks
George
On Sunday, Mar 2, 2003, at 11:38 US/Pacific, Charlie & Tupper England
wrote:
> Hi usually means audio; low usually means audio return or audio ground.
> Look at the radio's hookup diagram & be sure they aren't sending the
> 'high' to a speaker & the 'low' to the headphones.
>
> Audio 'grounds' are usually kept isolated from the airframe to prevent
> 'ground loops', or noise in the audio circuits.
>
> Hard to say about the unlabeled shield; it could be intended to provide
> noise shielding for the audio output wires & left floating at the
> other end.
>
Message 21
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| Subject: | Z-14 AND the RV6A (or 7A) ???? |
--> AeroElectric-List message posted by: "James E. Clark" <jclark@conterra.com>
Van's now mounts the battery on the firewall (under the cowl).
That is what we did on our "6" (done before Van did his) and I wish to mount
on the firewall this time, thus the problem.
If I were to put the inside the cabin on the floor next to the firewall all
would be fine but I have this other "preference".
James
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert
> L. Nuckolls, III
> Sent: Sunday, March 02, 2003 2:02 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Z-14 add the RV6A (or 7A) ????
>
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls,
> III" <bob.nuckolls@cox.net>
>
> At 11:29 AM 3/2/2003 -0500, you wrote:
> >--> AeroElectric-List message posted by: "James E. Clark"
> ><jclark@conterra.com>
> >
> >GlacierI am now working on an RV6A that I plan to make "all electric" per
> >Z-14.
> >
> >Has anyone out there on the list implemented Bob's "Z-14" (dual
> battery/dual
> >alternator) on the RV6/7A???
> >
> >If so I have a few questions:
> >
> >1. Which batteries did you use? (Bill of B&C recommends 2 of their 12AH
> >batteries ... fine by me)
> >2. Did you mount your batteries inside the cabin or on the firewall?
> >3. If you mounted them on the firewall (where I wish to), how
> did you do it
> >... one per side? Both on same side?
> >4. What about the mounting of the contactors?
> >5. If you mounteed them one per side, how was the wire run for
> >"interconnect" handled?
> >
> >Part of the problem I seem to be having is that I do not see how
> I can mount
> >the two batteries on the same side and I have not been able to find
> >batteries that are both suitable and much smaller.
> >
> >
> >Any advice (and especially pictures) would be appreciated before I go and
> >re-invent the wheel.
>
> As I recall, Van's plans call for a 24 a.h. battery
> on centerline, just behind the firewall. Given that
> a pair of 12 a.h. batteries has about the same footprint
> as a single 24 a.h. battery, could they not be mounted
> side-by-side in the same place as a 24 a.h. battery?
>
> Bob . . .
>
>
Message 22
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| Subject: | Shop Light Interference with Radio |
--> AeroElectric-List message posted by: "John H. Wiegenstein" <johnw@hellerwiegenstein.com>
Hi listers, I've been lurking a bit recently as my project gets into the
'lectrical phase, and have been perusing Bob's various diagrams and options
over the last several months. Today, though, I have a more generalized
question. I have commercial flourescent lights with electronic ballasts in
my shop, and while they do a good job and are efficient, they also generate
a hell of a lot of noise on the shop FM radio. Any suggestions on how to
cure this, so I can listen to more than one station? Reception is great
with the lights off, but with them on its a real bear - moving the radio and
power cord around don't do much..... TIA
John Wiegenstein
Hansville, WA
RV-6 N727JW (reserved) - engine hung, cowl and electrical in progress
johnw@hellerwiegenstein.com
Message 23
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|
| Subject: | Re: Z-14 AND the RV6A (or 7A) ???? |
--> AeroElectric-List message posted by: "Jim Pack" <jpack@igs3.com>
In the 9A, Vans puts the battery on the engine side of the firewall, pilots
side. I just added another battery on the CoPilot's side, same place. 17AH
batteries each.
- Jim
> Van's now mounts the battery on the firewall (under the cowl).
>
> That is what we did on our "6" (done before Van did his) and I wish to
mount
> on the firewall this time, thus the problem.
>
> If I were to put the inside the cabin on the floor next to the firewall
all
> would be fine but I have this other "preference".
>
> James
>
Message 24
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| Subject: | Shop Light Interference with Radio |
--> AeroElectric-List message posted by: "Terry Watson" <terry@tcwatson.com>
John,
I had a similar problem with my cheap stereo in the shop that has a
telescoping antenna. The problem was corrected by turning the FM antenna to
near horizontal.
Terry
--> AeroElectric-List message posted by: "John H. Wiegenstein"
<johnw@hellerwiegenstein.com>
Hi listers, I've been lurking a bit recently as my project gets into the
'lectrical phase, and have been perusing Bob's various diagrams and options
over the last several months. Today, though, I have a more generalized
question. I have commercial flourescent lights with electronic ballasts in
my shop, and while they do a good job and are efficient, they also generate
a hell of a lot of noise on the shop FM radio. Any suggestions on how to
cure this, so I can listen to more than one station? Reception is great
with the lights off, but with them on its a real bear - moving the radio and
power cord around don't do much..... TIA
Message 25
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| Subject: | Re: Shop Light Interference with Radio |
--> AeroElectric-List message posted by: N67BT@aol.com
I bought a XM (satellite) radio for the shop and plane. I think it's the
best deal on the planet. I get no interference from my 18 double florescent
light fixtures.
> I have commercial flourescent lights with electronic ballasts in
> my shop, and while they do a good job and are efficient, they also generate
> a hell of a lot of noise on the shop FM radio.
Bob Trumpfheller
Building a RV7A QB in Western Colorado
Message 26
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| Subject: | Re: Radio Wiring question |
--> AeroElectric-List message posted by: "Leonard Garceau" <lhgcpg@westriv.com>
I need some help finding a connector for an in tank highpressure fuel pump.
I need a connector that is gasoline proof and won't leak. I looked at an
automotive pump but couldn't find the connector. Any ideas how to run a
wire for my fuel pumps out of my tank.
Leonard
----- Original Message -----
From: "Vince Ackerman" <vack@mac.com>
Subject: AeroElectric-List: Radio Wiring question
> --> AeroElectric-List message posted by: Vince Ackerman <vack@mac.com>
>
> I'm a total novice so forgive me for the dumb questions. I can't get
> any tech support on weekends so I thought I'd ask here first.
>
> I'm trying to connect a DRE 244e intercom to a Garmin 250xl gps/com.
> The 250xl has the com wires coming from the rack labeled as follows:
>
> Each is a two wire twisted pair with shield
>
> 1st bundle
> Mic Audio Hi - white
> Mic Audio Key - blue/white (is this the PTT?)
> Mic Audio low - shield
>
> 2nd bundle
> Com Audio Hi - white
> Com Audio Low - blue/white
> Not labeled - shield (present but not labeled)
>
> The DRE 244e diagram shows a RAD cable from intercom connected to a
> radio as follows:
>
> green wire -- Earphone
> red wire -- Mic
> white wire -- PTT
> black and shield wire -- Gnd
>
> I'm not sure how to go about wiring this up. What does low/high on the
> 250xl mean? Is low the ground in the reference to DRE 244e diagram?
> The unlabeled shield on the com audio should be connected to what?
> Could anyone give me some help?
>
> Also, I need to make the instrument/ radio panel removable. Can I use
> molex type connectors between the radio rack wiring and the DRE 244?
> Will this cause interference/noise problems?
>
> I also have two PTT switch's located on my stick grips . The DRE 244e
> diagram shows these as wired off of the Pilot and Copilot headset wire
> bundles on the intercom, from each black wire (looks like it's the
> upper contact on the mike jack) and ground (shield) wire that run to
> the mic/headphone jacks. Rather than running another set of wires from
> the jacks, Can I intercept/splice into these wires closer to the
> intercom unit without worrying about inducing some sort of noise
> problems. They pass right next to the sticks. Also, Do the wires to
> the stick grips need to be twisted pair?
>
> Hope this is clear enough to figure out what I'm struggling with.
>
> Thanks for your assistance
>
> George Ackerman
>
>
Message 27
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
Higher rated switches are available, but I do not what physical size you
are referring to so I do not know if they meet your size requirements.
As far as AC43-13 goes, the derating factors there are for maximizing
the life of a switch used for a particular application. Since you have
a 12V system and since a lot of your loads are effectively resistive,
there is no derating there anyway. If you (religiously!) use a diode on
each and every relay or coil, then the diode is absorbing the energy
that would normally go into the switch at turnoff so the switch should
not need to be derated there either. Switches controlling motors should
be derated since it is difficult to predict what transients the motors
might generate at turn-on or turn-off. Lamps draw enormous currents at
turn-on so the switch should be derated appropriately or you might find
that you cannot turn it off after the contacts weld together. Of
course, if you have a "keep alive" or a "soft start" circuit for the
lamp filaments, that eliminates the turn-on surge.
Is a particular switch essential to the completion of the flight? Then
derate it appropriately. If not, then use your best judgement and
common sense.
Dick Tasker
Tinnemaha wrote:
>--> AeroElectric-List message posted by: "Tinnemaha" <Tinnemaha@charter.net>
>
>Thank You Richard,
>
>I will not put more than 4 Amps on one of these switches even in my 14 V system.
Can you tell me if higher rated mini switches are available? Where?
>
>What about the de-rating of switches mentioned in AC 43-13? Do you follow that
or is it too conservative?
>
> Grant
>
>
>
>
Message 28
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| Subject: | Re: Shop Light Interference with Radio |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:55 PM 3/2/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "John H. Wiegenstein"
><johnw@hellerwiegenstein.com>
>
>Hi listers, I've been lurking a bit recently as my project gets into the
>'lectrical phase, and have been perusing Bob's various diagrams and options
>over the last several months. Today, though, I have a more generalized
>question. I have commercial flourescent lights with electronic ballasts in
>my shop, and while they do a good job and are efficient, they also generate
>a hell of a lot of noise on the shop FM radio. Any suggestions on how to
>cure this, so I can listen to more than one station? Reception is great
>with the lights off, but with them on its a real bear - moving the radio and
>power cord around don't do much..... TIA
Have the same problem in a lab out at RAC . . . put up an outside
antenna with coax to bring signals into receiver. Extra signal +
more distance from interference did the trick.
Bob . . .
Message 29
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|
| Subject: | Z-14 AND the RV6A (or 7A) ???? |
--> AeroElectric-List message posted by: "James E. Clark" <jclark@conterra.com>
Are you using "Z-14 (Dual/Dual)"??
If so, how did you handle running the wire for interconnects?
Thanks,
James
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Jim
> Pack
> Sent: Sunday, March 02, 2003 7:25 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Z-14 AND the RV6A (or 7A) ????
>
>
> --> AeroElectric-List message posted by: "Jim Pack" <jpack@igs3.com>
>
> In the 9A, Vans puts the battery on the engine side of the
> firewall, pilots
> side. I just added another battery on the CoPilot's side, same
> place. 17AH
> batteries each.
>
> - Jim
>
>
> > Van's now mounts the battery on the firewall (under the cowl).
> >
> > That is what we did on our "6" (done before Van did his) and I wish to
> mount
> > on the firewall this time, thus the problem.
> >
> > If I were to put the inside the cabin on the floor next to the firewall
> all
> > would be fine but I have this other "preference".
> >
> > James
> >
>
>
>
>
>
>
Message 30
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| Subject: | Re: De-Rate Mini Switches? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:30 PM 3/2/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Richard E. Tasker"
><retasker@optonline.net>
>
>Higher rated switches are available, but I do not what physical size you
>are referring to so I do not know if they meet your size requirements.
>
>As far as AC43-13 goes, the derating factors there are for maximizing
>the life of a switch used for a particular application. Since you have
>a 12V system and since a lot of your loads are effectively resistive,
>there is no derating there anyway. If you (religiously!) use a diode on
>each and every relay or coil, then the diode is absorbing the energy
>that would normally go into the switch at turnoff so the switch should
>not need to be derated there either. Switches controlling motors should
>be derated since it is difficult to predict what transients the motors
>might generate at turn-on or turn-off. Lamps draw enormous currents at
>turn-on so the switch should be derated appropriately or you might find
>that you cannot turn it off after the contacts weld together. Of
>course, if you have a "keep alive" or a "soft start" circuit for the
>lamp filaments, that eliminates the turn-on surge.
>
>Is a particular switch essential to the completion of the flight?
Name a switch falls into this category . . .
>Then derate it appropriately. If not, then use your best judgement and
>common sense.
Most switches in light aircraft die of old age with fewer
than 10% of the manufacturer's rated operations.
De-rating is a useful thing to do for a commercial
airplane that sees perhaps 10-30 operating cycles per day. Owner
operated light aircraft see typically 50-100 operations per
YEAR . . . works out to .15 to .3 operations per day.
The guts of switches offered from B&C's website catalog
are the same as the rockers installed in single engine
Cessnas back in the 60's . . . the vast majority of those
ORIGINAL switches are still in service. Using miniature
switches is a whole new ball-game that may indeed call
for buffering (relay) for known high-stress tasks
like pitot heat and big lamps.
Bob . . .
Message 31
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| Subject: | Re: Z-14 AND the RV6A (or 7A) ???? |
--> AeroElectric-List message posted by: "Jim Pack" <jpack@igs3.com>
I put the battery contactors at the top of the firewall with the crossfeed
contactor between the battery contactors. The batteries are on the lower
two sides of the firewall.
- Jim
>
> Are you using "Z-14 (Dual/Dual)"??
>
> If so, how did you handle running the wire for interconnects?
>
> Thanks,
>
> James
> > > --> AeroElectric-List message posted by: "Jim Pack" <jpack@igs3.com>
> >
> > In the 9A, Vans puts the battery on the engine side of the
> > firewall, pilots
> > side. I just added another battery on the CoPilot's side, same
> > place. 17AH
> > batteries each.
> >
Message 32
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| Subject: | Wire bundles through firewall . . . |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
A few days ago, a general question popped up about wire bundles
through the firewall with specific question about EMI problems
that drive a requirement to separate some bundles. I put off
answering the question until after finishing the comic book
at
http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html
. . . but now, I can't find the original message. If the
questioner is on the list, check out the link above and know
that this particular airplane runs ALL wires that pass through
the firewall in the same bundle. The firewall fitting illustrated
is the only one on the airplane for wires. Everything else goes
through eye-balls or all metal bulkhead fittings for fluid
lines. There are no concerns for inter-system interference
by virtue of having routed all the wires together (This
is another thing that DO-160 does for us).
Some folks are enamored of putting connectors in
wire bundles so that removing an engine doesn't require
so much attention to disconnecting and re-connecting
individual conductors. For a time, Lancair even provided/
recommended an AMP CPC bulkhead feed-through for this
purpose. I wouldn't recommend any kind of plastic fitting
through a firewall.
If you want to include convenience connectors in large
wire count bundles, CPC connectors are fine but make
them cable/cable connectors pendant on a short bundle
of wires inside the engine compartment. You can wrap this
junction with a couple of layers of silicone guide-line
tape to reduce effects of environment on the connector.
Bob . . .
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