Today's Message Index:
----------------------
1. 05:01 AM - Re: 3-position switch (rd2@evenlink.com)
2. 06:46 AM - Re: Tach transducer (Kent Ashton)
3. 07:41 AM - Jig for wiring a 25 pin D-Sub connector (Neil Clayton)
4. 08:21 AM - Re: Jig for wiring a 25 pin D-Sub connector (KITFOXZ@aol.com)
5. 08:29 AM - Re: intermittent ignition on 912S (KITFOXZ@aol.com)
6. 08:39 AM - Re: Jig for wiring a 25 pin D-Sub connector (Malcolm Thomson)
7. 08:41 AM - Wire strippers redux (Robert L. Nuckolls, III)
8. 08:42 AM - Re: Wig Wag help (Robert L. Nuckolls, III)
9. 08:53 AM - Re: 12V VS. 24V Electrical System. (Robert L. Nuckolls, III)
10. 08:56 AM - Re: Architecture for 2 batteries and 1 alternator (Glaeser, Dennis A)
11. 09:23 AM - Re: 12V VS. 24V Electrical System. (Bruce Gray)
12. 09:35 AM - Re: 12V VS. 24V Electrical System. (BobsV35B@aol.com)
13. 10:03 AM - Re: Jig for wiring a 25 pin D-Sub connector (Phil Birkelbach)
14. 10:03 AM - Re: Re: iPod and altitude (Brian Lloyd)
15. 10:11 AM - Audio (Mickey Billings)
16. 10:28 AM - Re: 12V VS. 24V Electrical System. (Robert L. Nuckolls, III)
17. 11:02 AM - Re: 12V VS. 24V Electrical System. (Bruce Gray)
18. 11:17 AM - Re: Audio (Charlie England)
19. 11:57 AM - Re: Audio (Mickey Billings)
20. 01:27 PM - FW: Re: Architecture for 2 batteries and 1 alternator (Glaeser, Dennis A)
21. 06:18 PM - Re: Re: Architecture for 2 batteries and 1 alternator (Ken)
22. 06:19 PM - Re: FW: Re: Architecture for 2 batteries and 1 (Ken)
23. 08:40 PM - Re: 12V VS. 24V Electrical System. (Jim and Lucy)
24. 10:58 PM - Microair transponder problem (James Redmon)
Message 1
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| Subject: | Re: 3-position switch |
--> AeroElectric-List message posted by: rd2@evenlink.com
Thank you, Bob. One of these should do the job.
BTW,
>
There's no such thing as a "certified switch" . . . both of these
switches have been used at one time or another on certified
aircraft.
<
what log book entry should one make to keep the faa guys happy, if such
switch is installed in certified aircraft ? The switch actually replaces
the original 2 position toggle. (When bought from digikey, it comes with
invoice only and no tso.)
Rumen
_____________________Original message __________________________
(received from Robert L. Nuckolls, III; Date: 01:42 PM
8/8/2004 -0500)
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<rnuckolls@aeroelectric.com>
At 12:53 PM 8/7/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: BobsV35B@aol.com
>
>
>In a message dated 8/7/04 11:32:08 AM Central Daylight Time,
>rd2@evenlink.com writes:
>
>I was wondering if anyone could recommend/direct me to a source for an
>inexpensive, reliable, certified, small size 3-position switch (all
>positions "on") to be used to switch an autopilot between 3 signal sources
>(yaw signals from 2 VORs and a GPS). It could be a toggle or (preferably)
>rotary switch.
>Thanks
>Rumen
That's a tall order of mutually exclusive requirements. If your
heart is set on rotary switching, I'd recommend a Grayhill, totally
enclosed switch like the 56 series which can be found at Digikey's
catalog page http://dkc3.digikey.com/PDF/T042/1044.pdf
See 56D36-01-2-AJN in lower left corner of page.
My personal preference would be a 4 pole, progressive transfer,
three position toggle which can be wired to provide double-pole,
three position operation as described in Figure 11-16 of the
'Connection (except you have two poles of circuit instead of
one). A good switch for this task is a ITT-Cannon/CK 7411SYZQE
which you can also find in Digikey's catalog at:
http://dkc3.digikey.com/PDF/T042/1005.pdf
It's in the top group of switches, lower right hand corner of
top box.
There's no such thing as a "certified switch" . . . both of these
switches have been used at one time or another on certified
aircraft.
Bob . . .
---
Message 2
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| Subject: | Re: Tach transducer |
--> AeroElectric-List message posted by: Kent Ashton <kjashton@vnet.net>
Van's Aircraft sells a nice little tach transducer. It won't fit if you're
using a B&C oil filter adapter, though. It mounts on the tach drive on the
Lycoming.
--Kent
> From: "Steve Sampson" <SSampson.SLN21@london.edu>
> Reply-To: aeroelectric-list@matronics.com
> Date: Sun, 8 Aug 2004 18:44:46 +0100
> To: <aeroelectric-list@matronics.com>
> Subject: AeroElectric-List: Tach transducer
>
> --> AeroElectric-List message posted by: "Steve Sampson"
> <SSampson.SLN21@london.edu>
>
> I am installing a Grand Rapids 400 engine monitor. The tach signal come in
> one of two ways, either off the mag leads or from a transducer plugged into
> the location on a Lycoming where a mechanical tach fits.
>
> QUESTION Anyone know of a transducer that will fit in the Lycoming and give
> me a signal? An Aircraft Spruce part number would be ideal.
>
> (I have asked Grand Rapids this question twice now over 10 days but they
> seem to be having an extended lunch break!) I prefer the idea of using the
> port, since I would only have to buy a cover plate otherwise and switch
> signal source when checking the mags.
>
> Thanks, Steve
>
> RV9a #90360
>
> ---
>
>
>
>
>
>
Message 3
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| Subject: | Jig for wiring a 25 pin D-Sub connector |
--> AeroElectric-List message posted by: Neil Clayton <harvey4@earthlink.net>
Bob....I spent two frustrating hours trying to solder a D-sub connector
onto the 19+ wires of an Infinity Stick. The idea is to be able to remove
the stick during annuals, etc. I eventually threw up the idea and decided
there MUST be some kind of professional jig for wiring these things.
Can you direct me to such a device?
Many thanks
Neil
Message 4
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| Subject: | Re: Jig for wiring a 25 pin D-Sub connector |
--> AeroElectric-List message posted by: KITFOXZ@aol.com
In a message dated 8/9/2004 10:41:59 AM Eastern Standard Time,
harvey4@earthlink.net writes:
Bob....I spent two frustrating hours trying to solder a D-sub connector
onto the 19+ wires of an Infinity Stick. The idea is to be able to remove
the stick during annuals, etc. I eventually threw up the idea and decided
there MUST be some kind of professional jig for wiring these things.
Can you direct me to such a device?
Many thanks
Neil
Hello Neil,
I have used many home brewed jigs over the years to hold parts on the
"operating" table so that I can do surgery on them. A common solution is to get
some wooden spring loaded clothes pins and cut the nose of them off flush so
that they have a blunt nose. Take them apart and drill a hole in one side so
you can screw it down to a small slab of wood. Reassemble the clothes pins and
you have a handy hold for small stuff. I have a board with four of them
lined up with a few inches space between them. I can clip four wires across the
bench for tinning at once.
Try screwing a mate D-sub to a wooden board with the mating male/female pins
side up. Mate the male/female plug you are working on to it and you will
have the rascal held down good for soldering. Don't forget to be very clean
and try some liquid flux while you are at it. I wrote a posting about the
advantages to using liquid flux for this exact purpose a few weeks back.
Don't burn your fingers!
John P. Marzluf
Columbus, Ohio
Kitfox Outback (out back in the garage)
Message 5
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| Subject: | Re: intermittent ignition on 912S |
--> AeroElectric-List message posted by: KITFOXZ@aol.com
In a message dated 8/8/2004 10:14:47 PM Eastern Standard Time,
flyasuperseven@yahoo.com writes:
For the first time I noticed an intermittent ignition issue with my Rotax
912S. The right ignition controller cut out several times when doing a "mag"
check (on the ground of course). I couldn't get it to duplicate again since
though.
I carefully checked my wiring and also used an ohmmeter to check continuity
to see if there was a short causing that side to cut out. No joy.
Perhaps a problem with the starter switch (ACS unit)?
Anybody else with experience with this ignition and possibly some
suggestions? Thanks folks!
Joa
"who just *hates* intermittent electrical issues"
Joa,
Everybody hates intermittent electrical issues! The most common problem
found with the 912's ignition modules has been "broken" not "shorted" wires
coming immediately out of the ignition modules. They are very fine wires and
will not tolerate the relative motion of the harness shaking on the engine
without being tied down VERY securely. Many builders have located the modules
off
the engine. Carefully check out the wires and expect to find a break near
the module's case. Pull the wire jackets gently to see if you get some
stretch. If so, the wire is broken inside!
John P. Marzluf
Columbus, Ohio
Kitfox Outback (out back in the garage)
Message 6
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| Subject: | Jig for wiring a 25 pin D-Sub connector |
--> AeroElectric-List message posted by: "Malcolm Thomson" <mdthomson@attglobal.net>
If you use quality crimp pins, I believe it is faster and provides a
high quality connection. Also, it is easy to push pins out of the
connector if it becomes necessary to change anything. I also just wired
two of the Infinity Stick grips, the multiconductor cable goes down
through the stick. Only way to remove the grip now is to push the DB25
pins out of the connector. If they were soldered, you would have to
desolder the pins and start over.
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Neil
Clayton
Subject: AeroElectric-List: Jig for wiring a 25 pin D-Sub connector
--> AeroElectric-List message posted by: Neil Clayton
--> <harvey4@earthlink.net>
Bob....I spent two frustrating hours trying to solder a D-sub connector
onto the 19+ wires of an Infinity Stick. The idea is to be able to
remove
the stick during annuals, etc. I eventually threw up the idea and
decided
there MUST be some kind of professional jig for wiring these things. Can
you direct me to such a device?
Many thanks
Neil
==
direct advertising on the Matronics Forums.
==
==
==
Message 7
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| Subject: | Wire strippers redux |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
A few days ago, the topic of wire strippers circulated around
the list again. I did a short illustrated article on this topic
a couple years ago. I've updated this article with new information
and pictures. I'll encourage interested individuals to check it out
at: http://www.aeroelectric.com/articles/strippers/strippers.html
Bob . . .
---
Message 8
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| Subject: | Re: Wig Wag help |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 08:05 PM 8/8/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: "Jaye and Scott Jackson"
><jayeandscott@telus.net>
>
>First thing comes to mind is a problem I had wiring up my 6 as per Bob's
>manual: the switches' terminals didn't necessarily work as per the drawings.
>Had to use an ohmmeter, a good, hard look at how the switch was supposed to
>work in the drawings, and I think I scratched out about half my remaining
>hair.
>It all worked out in the end.
>Bob does alude to the fact that some of the switches he supplies have the
>terminals numbered differently than what he spec'd in the drawings.
>Scott in VAncouver
>RV-6
Here's a link to the data sheet that speaks to vairability
in terminal numbering between various brands of switches. See:
http://www.aeroelectric.com/articles/Carling_Micro/Carling_Micro.pdf
Bob . . .
---
Message 9
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| Subject: | Re: 12V VS. 24V Electrical System. |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
>In a message dated 08/08/2004 11:35:13 AM Central Standard Time,
>bob.nuckolls@cox.net writes:
> Wire weight savings was touted but there is so little wire
> in a single engine aircraft that smaller wires might account for
> a two or three pounds of savings.
>Another consideration: well over half the wire in my RV is 22 ga., the
>smallest wire recommended for routine wiring tasks due to mechanical
>considerations. Even if 24v would ALLOW smaller wire, I don't think I'd
>use it for this
>reason alone, therefore weight savings is much less a consideration, even
>with
>the fat wires going on a 24v diet...........
Exactly! The biggest weight savings comes from possible downsizing
of fat wires. Problem is that the biggest driver for fatwire selection
is cranking currents. If 24 volt starters would draw exactly 1/2 the current
of 12 v starters, then one might be able to rear-mount some batteries
in an RV or wire a nose mounted battery in a canard pusher with 4 AWG
wire and not compromise performance. My experience suggests that
24 volt starters are not that much lower in current draw. If one
sorts through all the wiring requirements through filters of
good practice and real historical numbers, I can find no compelling
reasons to jump on the 24 volt wagon for small aircraft.
I was told that the B-52 had over 500 miles of wire in it. Many runs
were 20-50 feet in length or more. To be sure, weight savings for 24v
on the order of hundreds of pounds could be realized making significant
changes in payload and range capabilities. But when your TOTAL wire
bundle weighs less than 10 pounds, you could only save 9.5 pounds
total by going to say, a 500 volt system . . . This example illustrates
how focus on weight savings is absurdly overshadowed by technical
and economic issues associated with increasing system voltage.
Bob . . .
---
Message 10
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| Subject: | Re: Architecture for 2 batteries and 1 alternator |
--> AeroElectric-List message posted by: "Glaeser, Dennis A" <dennis.glaeser@eds.com>
Ken,
I'm no expert either, that's why I'm looking for input such as yours! My
degree is Aerospace Engineering, so I know enough EE to just be dangerous
;-)
I agree with you that the 4 pole engine bus master is both expensive and a
single point of failure, and another is the 3 position fuel pump selector
switch. The engine electrical design is from the Eggenfeller Subaru
installation manual (that's the E-Subaru I'm talking about - not an EJ22 -
sorry for any confusion). (see: http://www.jlc.net/~fcs/EAA_IG/EA_IG_6.htm
<http://www.jlc.net/~fcs/EAA_IG/EA_IG_6.htm> for the gory details if you're
interested). I'm not familiar with the mechanically ganged switches you
mention - where can I find out more about them? The fuel pump setup in
their design has an auto-failover feature which is nice but the extra switch
is not. I haven't thought about relays (yet), I just modified their design
to not use the EXPBUS, which they recommend.
I do plan on an IFR machine. So, regarding the Aux battery - if I understand
correctly, you suggest a direct connect from the Alt to the Aux battery
through a diode - is that correct? The Aux Master would then be either
eliminated (aux battery used only to power the endurance bus when required)
or left in and used to power the main bus (is this what you mean by a
crossfeed contactor?). I'll probably keep the contactor, just to have the
capability to run the main bus from the Aux Bat if I want to. I did wonder
about just having the 2 batteries in parallel - I didn't think about a
failure which would drain them (but that possibility exists - probably what
was bothering me). I was wondering if turning off the Aux master
(especially prior to entering IMC) would be a good idea just to make it a
truly reserve battery, but it would also remove it from being charged. The
diode solves that!
Obviously this is a work in progress. I'm not building yet, so I have the
luxury of playing until I get it "right" (for me at least) on paper. I'll
be updating my diagram and reposting it one of these days. I appreciate
your inputs!.
Dennis
Message 11
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| Subject: | 12V VS. 24V Electrical System. |
--> AeroElectric-List message posted by: "Bruce Gray" <Bruce@glasair.org>
Bob,
Weight savings from wire size in a 24v system is not the issue.
Many years ago when I had my C177-RG's it was quite common when on final
at night with all the lights and radios on, to experience brown outs
when the gear was lowered. This was a 12v airplane and was back in the
days of power hungry radios. Cessna went to 24v systems a few years
later. The issue, in my opinion, is POWER.
Now, I realize that you're a strong proponent of the 12v system, I'm
not. There are many automotive components that are available in 24v
flavors. Most large trucks use 24v. Oh well, I guess we can agree to
disagree.
Bruce
www.glasair.org
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Subject: Re: AeroElectric-List: 12V VS. 24V Electrical System.
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<rnuckolls@aeroelectric.com>
>In a message dated 08/08/2004 11:35:13 AM Central Standard Time,
>bob.nuckolls@cox.net writes:
> Wire weight savings was touted but there is so little wire
> in a single engine aircraft that smaller wires might account for
> a two or three pounds of savings.
>Another consideration: well over half the wire in my RV is 22 ga., the
>smallest wire recommended for routine wiring tasks due to mechanical
>considerations. Even if 24v would ALLOW smaller wire, I don't think
I'd
>use it for this
>reason alone, therefore weight savings is much less a consideration,
even
>with
>the fat wires going on a 24v diet...........
Exactly! The biggest weight savings comes from possible downsizing
of fat wires. Problem is that the biggest driver for fatwire
selection
is cranking currents. If 24 volt starters would draw exactly 1/2 the
current
of 12 v starters, then one might be able to rear-mount some batteries
in an RV or wire a nose mounted battery in a canard pusher with 4 AWG
wire and not compromise performance. My experience suggests that
24 volt starters are not that much lower in current draw. If one
sorts through all the wiring requirements through filters of
good practice and real historical numbers, I can find no compelling
reasons to jump on the 24 volt wagon for small aircraft.
I was told that the B-52 had over 500 miles of wire in it. Many runs
were 20-50 feet in length or more. To be sure, weight savings for 24v
on the order of hundreds of pounds could be realized making
significant
changes in payload and range capabilities. But when your TOTAL wire
bundle weighs less than 10 pounds, you could only save 9.5 pounds
total by going to say, a 500 volt system . . . This example
illustrates
how focus on weight savings is absurdly overshadowed by technical
and economic issues associated with increasing system voltage.
Bob . . .
---
Message 12
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| Subject: | Re: 12V VS. 24V Electrical System. |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 8/9/04 11:24:48 AM Central Daylight Time,
Bruce@glasair.org writes:
The issue, in my opinion, is POWER.
Good Morning Bruce,
I have also become a proponent of the twenty-eight volt system. I have a
B&C standby alternator on my airplane. My full, everything on except pitot
heat and landing lights, night time loads are around twenty amps. (For What It's
Worth, the strobes, beacons and running lights account for almost half of
that load.)
My B&C can carry that load without even having to resort to a load reduction
regime.
When I first bought the airplane, I considered the twenty-eight volt system
to be a negative. I now consider it to be a strong plus.
On top of that, my gear retracts in less than four seconds. Twelve volt
versions of the same gear take from eight to twelve seconds to get tucked away.
Not really important, but way cool!
Color me VERY happy with twenty-eight volts.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 13
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| Subject: | Re: Jig for wiring a 25 pin D-Sub connector |
--> AeroElectric-List message posted by: Phil Birkelbach <phil@petrasoft.net>
I agree. I used a 25 Pin D-Dub for my infinity stick and it workes like
a champ. And I'll be able to get the grip off if I ever need to.
You'll most likely need the pin crimping tool for something else like
radio or transponder anyway.
If you still want to use the soldered connectors go to Radio Smack
("You've got questions, We've got dumb looks") and get one of those
little helping hand jigs that have the articulating aligator clips.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Panel
http://www.myrv7.com
Malcolm Thomson wrote:
>--> AeroElectric-List message posted by: "Malcolm Thomson" <mdthomson@attglobal.net>
>
>If you use quality crimp pins, I believe it is faster and provides a
>high quality connection. Also, it is easy to push pins out of the
>connector if it becomes necessary to change anything. I also just wired
>two of the Infinity Stick grips, the multiconductor cable goes down
>through the stick. Only way to remove the grip now is to push the DB25
>pins out of the connector. If they were soldered, you would have to
>desolder the pins and start over.
>
>
>-----Original Message-----
>From: owner-aeroelectric-list-server@matronics.com
>[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Neil
>Clayton
>To: aeroelectric-list@matronics.com
>Subject: AeroElectric-List: Jig for wiring a 25 pin D-Sub connector
>
>
>--> AeroElectric-List message posted by: Neil Clayton
>--> <harvey4@earthlink.net>
>
>Bob....I spent two frustrating hours trying to solder a D-sub connector
>onto the 19+ wires of an Infinity Stick. The idea is to be able to
>remove
>the stick during annuals, etc. I eventually threw up the idea and
>decided
>there MUST be some kind of professional jig for wiring these things. Can
>you direct me to such a device?
>
>Many thanks
>
>Neil
>
>
>==
>direct advertising on the Matronics Forums.
>==
>==
>==
>
>
>
>
Message 14
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| Subject: | Re: RE: iPod and altitude |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
On Aug 7, 2004, at 11:05 PM, James Foerster wrote:
> --> AeroElectric-List message posted by: "James Foerster"
> <jmfpublic@comcast.net>
>
> Music lovers:
>
> Rather than pressurize the iPod, getting a solid state MP3 player
> makes more sense. I saw that 1 GB of compact flash memory was $169 at
> Best Buy recently, and prices will only drop.
The problem with the flash-based MP3 players is that they won't hold
all your music.
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 15
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--> AeroElectric-List message posted by: "Mickey Billings" <mbilli@cox.net>
Does anyone know the difference between audio high and audio low on the
radio pin output?
Message 16
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| Subject: | 12V VS. 24V Electrical System. |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 12:23 PM 8/9/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: "Bruce Gray" <Bruce@glasair.org>
>
>Bob,
>
>Weight savings from wire size in a 24v system is not the issue.
>
>Many years ago when I had my C177-RG's it was quite common when on final
>at night with all the lights and radios on, to experience brown outs
>when the gear was lowered. This was a 12v airplane and was back in the
>days of power hungry radios. Cessna went to 24v systems a few years
>later. The issue, in my opinion, is POWER.
>
>Now, I realize that you're a strong proponent of the 12v system, I'm
>not. There are many automotive components that are available in 24v
>flavors. Most large trucks use 24v. Oh well, I guess we can agree to
>disagree.
Your example is anecdotal. No DATA. Your observations about
brownout cannot be argued with, what's missing is: What are
the simple-ideas, the physics surrounding the observed phenomenon?
If you'd let me rewire that airplane with one of the Z-figure
architectures using MODERN RG batteries, I suspect I could
make the observed phenomenon go away and still have the 12 volt
system. To make a blanket assumption that a 24 volt upgrade
was critical to improved performance. It may have been the
"simple" solution for the designers . . . things may have
got better with the "upgrade" . . . without changing the
architecture or taking time to truly understand the benefits
of alternative architectures combined with much improved, modern
components. It's the response we've come to expect from the
certified world. I can almost always sell some sort of band-aid
to an existing system. It's nigh well impossible to really
make a quantum leap change to bring a system into the 21st
century.
One has to make decisions based on what they know and understand.
I'm not suggesting that 24 volt systems are "bad", I've cited
numerous occasions wherein I've enthusiastically supported and
aided in the design of such systems. I am suggesting that much
of what passes for data handed down from our past experience in
the Jurasic Park of aviation is incomplete or in error. Your
24 volt system has a high order probability of performing just
fine and I would not suggest you change it out in favor of a
12 volt system. I'm only suggesting that folks in the decision-
making mode take the time to gather and understand all the data.
If anecdotal info is sought, get it from other RV or Cozy
builders, NOT from C-172 or PA-28 drivers.
Bob . . .
"One can know a great deal about something
and still understand nothing."
C.F. Kettering
---
Message 17
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| Subject: | 12V VS. 24V Electrical System. |
--> AeroElectric-List message posted by: "Bruce Gray" <Bruce@glasair.org>
OK, I still like your ideas about other things, just not this one. My
airplane, and it's electrical system, are all anecdotal. It's sort of
like horse power, you never have enough. It's a personal thing.
Now, where did I put that 500VAC inverter?
Bruce
www.glasair.org
GIII- 28v
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Robert L. Nuckolls, III
Subject: RE: AeroElectric-List: 12V VS. 24V Electrical System.
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<rnuckolls@aeroelectric.com>
Your example is anecdotal. No DATA. Your observations about
brownout cannot be argued with, what's missing is: What are
the simple-ideas, the physics surrounding the observed phenomenon?
If you'd let me rewire that airplane with one of the Z-figure
architectures using MODERN RG batteries, I suspect I could
make the observed phenomenon go away and still have the 12 volt
system. To make a blanket assumption that a 24 volt upgrade
was critical to improved performance. It may have been the
"simple" solution for the designers . . . things may have
got better with the "upgrade" . . . without changing the
architecture or taking time to truly understand the benefits
of alternative architectures combined with much improved, modern
components. It's the response we've come to expect from the
certified world. I can almost always sell some sort of band-aid
to an existing system. It's nigh well impossible to really
make a quantum leap change to bring a system into the 21st
century.
One has to make decisions based on what they know and understand.
I'm not suggesting that 24 volt systems are "bad", I've cited
numerous occasions wherein I've enthusiastically supported and
aided in the design of such systems. I am suggesting that much
of what passes for data handed down from our past experience in
the Jurasic Park of aviation is incomplete or in error. Your
24 volt system has a high order probability of performing just
fine and I would not suggest you change it out in favor of a
12 volt system. I'm only suggesting that folks in the decision-
making mode take the time to gather and understand all the data.
If anecdotal info is sought, get it from other RV or Cozy
builders, NOT from C-172 or PA-28 drivers.
Bob . . .
"One can know a great deal about something
and still understand nothing."
C.F. Kettering
Message 18
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--> AeroElectric-List message posted by: Charlie England <ceengland@bellsouth.net>
Mickey Billings wrote:
>--> AeroElectric-List message posted by: "Mickey Billings" <mbilli@cox.net>
>
>Does anyone know the difference between audio high and audio low on the
>radio pin output?
>
Typically, high=signal, low=signal return (ground, in common
terminology). Sometimes separate grounds for separate signals are for
convenience, but usually it's to minimize noise (ground loops, etc.).
Charlie
Message 19
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--> AeroElectric-List message posted by: "Mickey Billings" <mbilli@cox.net>
Thanks Charlie that makes sense!
----- Original Message -----
From: "Charlie England" <ceengland@bellsouth.net>
Subject: Re: AeroElectric-List: Audio
> --> AeroElectric-List message posted by: Charlie England
<ceengland@bellsouth.net>
>
> Mickey Billings wrote:
>
> >--> AeroElectric-List message posted by: "Mickey Billings"
<mbilli@cox.net>
> >
> >Does anyone know the difference between audio high and audio low on the
> >radio pin output?
> >
>
> Typically, high=signal, low=signal return (ground, in common
> terminology). Sometimes separate grounds for separate signals are for
> convenience, but usually it's to minimize noise (ground loops, etc.).
>
> Charlie
>
>
Message 20
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| Subject: | Re: FW: Re: Architecture for 2 batteries and 1 alternator |
--> AeroElectric-List message posted by: "Glaeser, Dennis A" <dennis.glaeser@eds.com>
I started to play with isolating the Aux Battery with a diode and making the
contactor a crossover contactor (if I'm using that term correctly) per Ken's
suggestion. The problem with that scheme is that the Aux battery is now not
available to help with starting the engine, since it is no longer in
parallel. I also remembered that there is an article on the Aeroelectric
site which discussed this, and I found it:
http://www.aeroelectric.com/articles/bat_iso2.pdf
<http://www.aeroelectric.com/articles/bat_iso2.pdf> I knew that I
basically lifted my design from one of Bob's diagrams, and this article has
it. His Figure 2 is essentially the design I copied - without the Aux
Battery Management Module shown in that article (I went with the manual
option). The failure mode that Ken mentions which could drain both
batteries still concerns me, although the ABMM in Bob's design would
immediately isolate the Aux battery if such a drain occurred (I think). I
went with the manual mode because I do have LV warning. My question is:
what kind of failure could occur which would NOT trigger the LV warning, but
could drain the batteries?
Dennis
> -----Original Message-----
> From: Glaeser, Dennis A
> Sent: Monday, August 09, 2004 11:56 AM
> To: 'aeroelectric-list@matronics.com'
> Subject: Re: Architecture for 2 batteries and 1 alternator
>
> Ken,
>
> I'm no expert either, that's why I'm looking for input such as yours! My
> degree is Aerospace Engineering, so I know enough EE to just be dangerous
> ;-)
>
> I agree with you that the 4 pole engine bus master is both expensive and a
> single point of failure, and another is the 3 position fuel pump selector
> switch. The engine electrical design is from the Eggenfeller Subaru
> installation manual (that's the E-Subaru I'm talking about - not an EJ22 -
> sorry for any confusion). (see: http://www.jlc.net/~fcs/EAA_IG/EA_IG_6.htm
> <http://www.jlc.net/~fcs/EAA_IG/EA_IG_6.htm> for the gory details if
> you're interested). I'm not familiar with the mechanically ganged
> switches you mention - where can I find out more about them? The fuel
> pump setup in their design has an auto-failover feature which is nice but
> the extra switch is not. I haven't thought about relays (yet), I just
> modified their design to not use the EXPBUS, which they recommend.
>
> I do plan on an IFR machine. So, regarding the Aux battery - if I
> understand correctly, you suggest a direct connect from the Alt to the Aux
> battery through a diode - is that correct? The Aux Master would then be
> either eliminated (aux battery used only to power the endurance bus when
> required) or left in and used to power the main bus (is this what you mean
> by a crossfeed contactor?). I'll probably keep the contactor, just to
> have the capability to run the main bus from the Aux Bat if I want to. I
> did wonder about just having the 2 batteries in parallel - I didn't think
> about a failure which would drain them (but that possibility exists -
> probably what was bothering me). I was wondering if turning off the Aux
> master (especially prior to entering IMC) would be a good idea just to
> make it a truly reserve battery, but it would also remove it from being
> charged. The diode solves that!
>
> Obviously this is a work in progress. I'm not building yet, so I have the
> luxury of playing until I get it "right" (for me at least) on paper. I'll
> be updating my diagram and reposting it one of these days. I appreciate
> your inputs!.
>
> Dennis
Message 21
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| Subject: | Re: Architecture for 2 batteries and 1 alternator |
on juliet
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Hi Dennis
comments are embedded below.
Ken
Glaeser, Dennis A wrote:
>--> AeroElectric-List message posted by: "Glaeser, Dennis A" <dennis.glaeser@eds.com>
>
>Ken,
>
>I'm no expert either, that's why I'm looking for input such as yours! My
>degree is Aerospace Engineering, so I know enough EE to just be dangerous
>;-)
>
>I agree with you that the 4 pole engine bus master is both expensive and a
>single point of failure, and another is the 3 position fuel pump selector
>switch. The engine electrical design is from the Eggenfeller Subaru
>installation manual (that's the E-Subaru I'm talking about - not an EJ22 -
>sorry for any confusion). (see: http://www.jlc.net/~fcs/EAA_IG/EA_IG_6.htm
><http://www.jlc.net/~fcs/EAA_IG/EA_IG_6.htm> for the gory details if you're
>interested).
>
Since Egenfellner uses the Subaru computer, that makes it a Subaru
regardless of what they call it in my mind so I think we are talking
about the same thing pretty much.
> I'm not familiar with the mechanically ganged switches you
>mention - where can I find out more about them? The fuel pump setup in
>their design has an auto-failover feature which is nice but the extra switch
>is not. I haven't thought about relays (yet), I just modified their design
>to not use the EXPBUS, which they recommend.
>
>
As far as mechanically ganged switches, my plan was to just line up some
toggle switches side by side about an inch apart. Then drill some holes
1" apart in a 1/8" x 1/2" bar of aluminum. Place the aluminum bar over
the toggles so that the toggles protrude into the holes and then put a
hinge on each end of the aluminum bar so that moving the aluminum bar
moves all the switch toggles together.( My application is slightly more
complicated in that some of the holes are slots so that some of the
toggles can be moved in one direction without moving the bar) However
when the bar is moved up or down all the switches will be positioned
where I want them. There are some pricey Honeywell switches made from
microswitches stacked side by side and actuated by one toggle but I kind
of like completely separate switches with no common parts for this
application.
>I do plan on an IFR machine. So, regarding the Aux battery - if I understand
>correctly, you suggest a direct connect from the Alt to the Aux battery
>through a diode - is that correct?
>
Well not quite. In most cases you don't want to run the alternator
without a two way connection (no diodes) to a battery. I decided not to
put a battery contactor between my main alternator and my battery but
let's ignore that for now - at least until Paul M. presents his research
on that.
> The Aux Master would then be either
>eliminated (aux battery used only to power the endurance bus when required)
>or left in and used to power the main bus (is this what you mean by a
>crossfeed contactor?). I'll probably keep the contactor, just to have the
>capability to run the main bus from the Aux Bat if I want to. I did wonder
>about just having the 2 batteries in parallel - I didn't think about a
>failure which would drain them (but that possibility exists - probably what
>was bothering me). I was wondering if turning off the Aux master
>(especially prior to entering IMC) would be a good idea just to make it a
>truly reserve battery, but it would also remove it from being charged. The
>diode solves that!
>
>
Yes I think that might be the way to go. I'm not familiar with it but
isn't Bob's Aux battery management module designed to add a second
battery and do pretty much what you want?
Anyway Bob's Z-30 keeps the contactors pretty much as per your diagram.
And elsewhere he shows how to wire the start switch to automatically
close the contactor during engine cranking. So yes I'm suggesting that
you leave the aux battery contactor open except for engine starting then
but bypass it with one of the 25 amp diode blocks so that it can always
accept a charge. (Or maybe use one of Eric's shotky diodes for an even
lower voltage drop.) Wired like that I'd call it a crossfeed contactor
instead of an aux battery contactor but an apple is an apple no matter
what we call it ;)
>Obviously this is a work in progress. I'm not building yet, so I have the
>luxury of playing until I get it "right" (for me at least) on paper. I'll
>be updating my diagram and reposting it one of these days. I appreciate
>your inputs!.
>
>Dennis
>
>
>
Message 22
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| Subject: | Re: FW: Re: Architecture for 2 batteries and 1 |
alternator
on juliet
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Glaeser, Dennis A wrote:
>--> AeroElectric-List message posted by: "Glaeser, Dennis A" <dennis.glaeser@eds.com>
>
>I started to play with isolating the Aux Battery with a diode and making the
>contactor a crossover contactor (if I'm using that term correctly) per Ken's
>suggestion. The problem with that scheme is that the Aux battery is now not
>available to help with starting the engine, since it is no longer in
>parallel. I also remembered that there is an article on the Aeroelectric
>site which discussed this, and I found it:
>http://www.aeroelectric.com/articles/bat_iso2.pdf
><http://www.aeroelectric.com/articles/bat_iso2.pdf> I knew that I
>basically lifted my design from one of Bob's diagrams, and this article has
>it. His Figure 2 is essentially the design I copied - without the Aux
>Battery Management Module shown in that article (I went with the manual
>option). The failure mode that Ken mentions which could drain both
>batteries still concerns me, although the ABMM in Bob's design would
>immediately isolate the Aux battery if such a drain occurred (I think). I
>went with the manual mode because I do have LV warning. My question is:
>what kind of failure could occur which would NOT trigger the LV warning, but
>could drain the batteries?
>
> Dennis
>
>
Probably none except a failure of the LV warning itself?
Or maybe the pilot not noticing the LV warning?
The combination of a LV warning and occasionally glancing at a voltmeter
should be pretty reliable I'd think.
Ken
Message 23
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| Subject: | 12V VS. 24V Electrical System. |
--> AeroElectric-List message posted by: Jim and Lucy <jpollard@mnsi.net>
At 12:23 PM 8/9/2004 -0400, you wrote:
>Most large trucks use 24v
I think the reason for this in trucks and other
big diesels is for the starter. 12v just does not
seem to be good enough when these big engines get
to be a certain size. Even with a pair of giant
batteries. They used air starters for a while
probably still do on some things. A three or five
hundred horse diesel at 18 - 1 compression ratio
takes a lot of torque to get it up to speed. One
machine we have uses 12 volts for everything but
the starter. Its got a series parallel contactor
for the starter circuit. It was alot of expense and complication
to build it like that but there was no starter available at 12
volts to start this machine. Starter weighs about 80 lbs.
Jim Pollard
Message 24
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| Subject: | Microair transponder problem |
--> AeroElectric-List message posted by: "James Redmon" <james@berkut13.com>
All,
I hope this is not too far off topic....
I had a very stringent pitot/static/transponder checkout performed this last
weekend. The EFIS-Lite passed with flying colors, as did all my plumbing.
However, my brand new out of the box Microair T2000SFL plain flat FAILED the
tests.
It had good power, stable and clear frequency and signal, but would only
respond to <50% of the looped interrogations. The data coming back from the
unit was good only every .5 to 1 second, randomly. Not enough good data to
really determine pulse width, and other specifics.
We checked all the standard stuff - voltage, antenna, BNC connectors, coax,
correct 5.5" diameter ground plane, possible interference, etc. All good.
Anyone else having the same problems and how was it solved? I'm grounded
from first flight until this gets resolved.
James Redmon
Berkut #013 N97TX
http://www.berkut13.com
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