Today's Message Index:
----------------------
1. 01:50 AM - Re: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 (Kevin Horton)
2. 02:06 AM - Re: Re: Grommets (Kevin Horton)
3. 04:14 AM - Encoding Altimeter ()
4. 04:57 AM - Re: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 (Ken)
5. 05:33 AM - Re: Dual alternator single shunt (David & Elaine Lamphere)
6. 06:36 AM - Re: LED Landing Lights (Robert L. Nuckolls, III)
7. 06:36 AM - Re: Garmin 250XL problem (Robert L. Nuckolls, III)
8. 07:04 AM - Re: Dual alternator single shunt (MartinErni@aol.com)
9. 07:22 AM - Re: Re: LED Landing Lights (Bill Denton)
10. 07:42 AM - Re: Non-tso altitude encoder, was Questions on avionics (Glen Matejcek)
11. 09:14 AM - Re: ELT Antenna for Fiberglass aircraft (BobsV35B@aol.com)
12. 10:29 AM - Re: Dual alternator single shunt (Ron Shannon)
13. 11:26 AM - FOR SALE, RV6A (cecilth@juno.com)
14. 03:54 PM - Re: Dual alternator single shunt (MartinErni@aol.com)
15. 06:36 PM - Re: Dual alternator single shunt (Robert L. Nuckolls, III)
16. 06:38 PM - Re: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 (Robert L. Nuckolls, III)
17. 06:41 PM - Battery bus (Robert L. Nuckolls, III)
18. 06:42 PM - Re: Dual alternator single shunt (Robert L. Nuckolls, III)
19. 06:44 PM - Re: Dual alternator single shunt (Robert L. Nuckolls, III)
20. 06:57 PM - Re: Dual alternator single shunt (MartinErni@aol.com)
21. 07:57 PM - Re: Dual alternator single shunt (David & Elaine Lamphere)
22. 08:38 PM - Re: Dual alternator single shunt (Ron Shannon)
23. 08:45 PM - Re: Battery bus (Ron Shannon)
24. 08:45 PM - Pinout for Softcom ATC-P and Website Maintenance (Robert L. Nuckolls, III)
25. 09:33 PM - Re: A Bit of Help, Please (Speedy11@aol.com)
26. 10:14 PM - Re: LED Landing Lights (Speedy11@aol.com)
27. 10:17 PM - Re: Keep Alive (Speedy11@aol.com)
28. 10:21 PM - Re: Keep Alive (Speedy11@aol.com)
Message 1
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Subject: | Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 |
On 21 Apr 2008, at 01:58, Lee Logan wrote:
> I am in the process of completing the wiring design/effort on my
> homebuilt F1 Rocket and am "planning" on not using a battery bus,
> just a main and endurance buses. I'm using Z-13/8 (conventional
> mags), but don't see a need for a "keep alive" circuit with my
> avionics suite (not do I need power for an electronic ignition
> system). I see that other builders have put all sorts of things on
> their battery bus, such as flaps, clocks, etc. Since I may be
> missing something here, I'm asking: What does the "List" think
> ought to be on a "modern" battery bus and what rationale is
> commonly used to justify those selections, please...
I'd put anything that needed "keep alive" power, and anything that
you absolutely need to have running if you kill the battery master
and alternator following a "smoke in the cockpit" event. In my case,
I will fly IFR, so I need something to help me keep the wings level -
I put my turn and bank on the battery bus. You want as little as
possible on the battery bus, to maximize the chance that you can stop
the smoke by killing the electrics.
Given your situation, I agree that there may be no need for a battery
bus.
--
Kevin Horton
RV-8 (FInal Assembly)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 2
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I would expect proper aviation grommets to be OK, as long as they
were installed in proper sized holes. These grommets are made to
military specifications, and should have been well tested in aviation
environments. The ones with narrow grooves are certainly intended to
be installed in thin sheet.
Putting a grommet in an undersized hole (as the original poster did)
is using the grommet in a way that the designer never intended. In
this case, all the design work and testing that the manufacturer did
is is no longer relevant, as is the previous service history. You
now are on your own, and have to do your own testing to establish an
envelope of conditions under which the grommet functions properly.
The original poster has learned that one type of non-aviation
grommet, installed in an undersized hole, is not appropriate for
aviation use.
--
Kevin Horton
On 20 Apr 2008, at 14:45, Ken wrote:
>
> Another product that may be suitable is the plastic snap bushings
> such as Spruce 04-05730. I never liked putting soft grommets from
> any source in very thin metal.
> Ken
>
> Jeff Page wrote:
>> Two of you both thought my grommet problem so absurd that it must
>> be a prank.
>> I wish that were true, but my T hangar is locked.
>> They were exposed only to cold air, darkness, time and my
>> installation.
>> When I get to the hangar next, i will be taking a close look at
>> all of them, to see if the ones remaining are partly torn, or if
>> some of them are perfectly intact.
>> I will also try to do some tests with some still in the box to see
>> if I can tear them like that.
>> Sure is weird though. We install grommets to protect the wires,
>> so they should be tougher than the insulation.
>> Jeff
>>> Are you sure someone didn't cut them off, just to play a mind
>>> game with
>>> you??
>>>
>>> Roger
>>>> Just a guess but exposure to solvents could breakdown SBR. I
>>>> cannot
>>>> imagine that hole size alone is the issue.
>>> I will chime in and comment.... This is really hard to believe
>>> they spli
>>> t all by themselves. Are you sure someone didn't remove them and
>>> split t
>>> hem with a razor and them drop them on the floor as a joke/ prank
>>> etc...
>>>
>>> Ben Haas
>
Message 3
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Subject: | Encoding Altimeter |
4/20/2008
Hello Anonymous, You wrote:
1) "You seem to be saying that the only practical way to meet the
requirements is to use a TSO'd source for the altitude information the
transponder is transmitting."
That is close. Here is how I would phrase it: "At present the only practical
way to be in compliance with FAR Section 91.217, Data Correspondence Between
Automatically Reported Pressure Altitude Data and the Pilot's Altitude
Reference, is to use a TSO'd equipment source for the altitude information
the transponder is transmitting."
2) "That, of course, would eliminate valuable functionality of many
non-TSO'd electronic EFISs including the serial output to the transponder."
Specifically, the serial altitude data output to the transponder from a non
TSO'd altitude encoder within an EFIS would not, at present, be in
compliance
with either 91.217 (b) or (c).
3) "Clearly, that isn't happening in the real world. These are selling
well."
Correct.
4) "Are you against that?"
Not at all. Here are my positions:
A) People should make informed decisions.
B) If I can provide accurate information to people that will permit them to
make informed decisions I should do so.
C) The decisions that those people make, after I have given them the best
information that I have available, is theirs to make, not mine. The risks
that they chose to take, or not take, are theirs, not mine.
D) Most of the EFIS available to the amateur built community represent a
significant improvement in performance, reliability, and safety over
previously available flight instrument technology.
E) Most of the EFIS available to the homebuilt community contain a non-TSO'd
altitude encoder that is superior in performance, reliability, granularity,
and accuracy over altitude encoding equipment that was manufactured to
versions of TSO-C88 prior to TSO-C88b.
F) Amateur built experimental aircraft have flown thousands of hours using
EFIS with non-TSO'd altitude encoders feeding their transponders with no
apparent problems.
G) Hundreds of amateur built experimental airplanes are under construction
using EFIS containing non-TSO'd altitude encoders.
H) The FAA should recognize and accept the real world conditions described
in D, E, F, and G above.
I) The best way for the FAA to accept the real world conditions described in
D, E, F, and G above is to interpret the tests required by FAR Secs 91.411
and 91.413 (as appropriate) as fulfilling the requirements of FAR Sec 91.217
(b).
J) My initial attempts to accomplish H and I above with FAA HQ were met with
resistance and I ceased activity in this regard.**
K) If the FAA, and the people / entities who perform the tests required by
91.411 / 91.413, decided that every non-TSO'd altitude encoder in an EFIS
was not airworthy because it did not meet the requirements of either 91.217
(b) or (c) this decision would be a serious blow to the amateur built
community.**
L) I do not proactively broadcast the information in K above, but if someone
asks a specific question on this issue or posts a position that I know to be
in error I revert to my positions A and B above.
M) I am open to improvements or changes in my positions.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
**PS: The FAA decision makers who perpetrated the recent fiasco involving
hundreds of airline flights being canceled and thousands of people being
stranded over the issue of the exact spacing of electrical wire cable ties
in the landing gear wheel wells of airline aircraft are capable of such
thinking and actions.
------------------------------------------------------------
----- Original Message -----
From: Anonymous
Sent: Sunday, April 20, 2008 9:20 AM
Subject: Encoding Altimeter
> OC,
>
> I don't understand what you are trying to say with your posts
> to
> the AeroElectric List. You seem to be saying that the only practical way
> to
> meet the requirements is to use a TSO'd source for the altitude
> information
> the transponder is transmitting. That, of course, would eliminate
> valuable
> functionality of many non-TSO'd electronic EFISs including the serial
> output
> to the transponder. Clearly, that isn't happening in the real world.
> These
> are selling well. Are you against that?
Anonymous
Message 4
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Subject: | Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 |
I also use a battery bus cigarette lighter receptacle for several
things. Programming handheld gps, blowing up air mattresses, powering a
small inverter for a soldering iron, dremel tool etc. It was really
installed to power handheld devices in flight after everything else was
shut off. I also put a switch beside the receptacle to kill it which is
handier than unplugging stuff sometimes. LED dome lights are also on
that circuit. I have additional cig. lighter receptacles that get power
through the batt master contactor.
Ken
Dale Ensing wrote:
> I have a small battery bus for the 'keep alive' for the clock in my
> engine monitor and for a 12 voltv cig. lighter outlet which I use for
> the Battery Minder to maintain the battery in the hangar and accesories
> like my XM radio when flying. Happy with that set up.
> Dale Ensing
>
> ----- Original Message -----
> *From:* Lee Logan <mailto:leeloganster@gmail.com>
> *To:* aeroelectric-list@matronics.com
> <mailto:aeroelectric-list@matronics.com>
> *Sent:* Sunday, April 20, 2008 8:58 PM
> *Subject:* AeroElectric-List: Re: AeroElectric-List Digest: 10 Msgs
> - 04/19/08
>
> I am in the process of completing the wiring design/effort on my
> homebuilt F1 Rocket and am "planning" on not using a battery bus,
> just a main and endurance buses. I'm using Z-13/8 (conventional
> mags), but don't see a need for a "keep alive" circuit with my
> avionics suite (not do I need power for an electronic ignition
> system). I see that other builders have put all sorts of things on
> their battery bus, such as flaps, clocks, etc. Since I may be
> missing something here, I'm asking: What does the "List" think
> ought to be on a "modern" battery bus and what rationale is commonly
> used to justify those selections, please...
>
> Regards,
>
> Lee...
Message 5
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Subject: | Re: Dual alternator single shunt |
Will this position of the shunt cause any problems when the engine
starter is engaged?? (as in peg the meter)
Dave
----- Original Message -----
From: Ron Shannon
To: aeroelectric-list@matronics.com
Sent: Sunday, April 20, 2008 8:47 PM
Subject: Re: AeroElectric-List: Dual alternator single shunt
Thanks for the input. Physically, that's roughly where my shunt will
be too, on the FW about 8" or less from the FW ground stud, contactors,
battery, etc. (Only one battery here.) I'm just trolling the group
wisdom to confirm I'm not creating some unanticipated electrical risk
with a single shunt downstream from the two alternators' ANLs.
Ron
On Sun, Apr 20, 2008 at 5:09 PM, <MartinErni@aol.com> wrote:
Ron,
I found it easier to place the shunt next to my common ground
block that goes to both batteries.
Earnest
Message 6
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Subject: | Re: LED Landing Lights |
At 08:59 AM 4/20/2008 -0700, you wrote:
>Stan,
>I've been watching the development of Landing Lights over the last several
>years as I build my Velocity. It used to be the cost of flying was enough
>to rationalize keeping on building rather than actually finishing and
>taking the plane out of the garage. Now it seems the advances in LED
>technology may be a new way to rationalize! I'm curious if you've lit
>these up yet and can give us an impression of how well they light compared
>to the other technologies out there (filament, halogen, HID, etc.). Can
>you give us a quick user report? What model are you using?
>
>Thanks,
>Dan
I'm not at liberty to speak to details but know that
the TC aircraft guys are presently evaluating LED
landing and taxi light products in a right-left
comparison of new and old technologies on existing
high-performance aircraft. When the go/no-go
decisions are made and they're ready to share
their findings, I'll let you all know.
At first blush, it's a no-brainer. Incandescent
lamps will soon be a thing of the past.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 7
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Subject: | Re: Garmin 250XL problem |
At 10:34 AM 4/20/2008 -0700, you wrote:
>I have a VariEze with a Garmin 250XL GPS/COM. I accidentally shut off the
>master while flying and because of my B&C 8 amp. permanent magnet
>alternator I continued to feed power to the buss until I rolled out on
>landing. At that point the instruments showed intermittent low voltage and
>were flickering and cutting out. I discover the reason and turned the
>master back on. The next flight my 250XL began to flick off and back on in
>a split second several times at regular 4-5 min. intervals. It continued
>to work fine as it was on, but the GPS had to reboot each time. It appears
>that I have damaged some internal component with the low voltage episode.
>Does anyone know if this can be fixed easily or am I looking at a major
>circuit change-out?
I can't speak to the potential for damage to your
accessories but I can suggest a review of your system
architecture that allows operator mis-positioning of
switches to produce an alternator-only powering of
the bus.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 8
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Subject: | Re: Dual alternator single shunt |
I put the starter ground on the same side of the shunt as the battery
grounds. All other grounds attach to the other side of the shunt, so the answer
is
"no".
Earnest
In a message dated 4/21/2008 8:36:06 A.M. Eastern Daylight Time,
lamphere@vabb.com writes:
Will this position of the shunt cause any problems when the engine starter
is engaged?? (as in peg the meter)
Dave
----- Original Message -----
From: _Ron Shannon_ (mailto:rshannon@cruzcom.com)
(mailto:aeroelectric-list@matronics.com)
Sent: Sunday, April 20, 2008 8:47 PM
Subject: Re: AeroElectric-List: Dual alternator single shunt
Thanks for the input. Physically, that's roughly where my shunt will be too,
on the FW about 8" or less from the FW ground stud, contactors, battery,
etc. (Only one battery here.) I'm just trolling the group wisdom to confirm I'm
not creating some unanticipated electrical risk with a single shunt
downstream from the two alternators' ANLs.
Ron
On Sun, Apr 20, 2008 at 5:09 PM, <_MartinErni@aol.com_
(mailto:MartinErni@aol.com) > wrote:
Ron,
I found it easier to place the shunt next to my common ground block that
goes to both batteries.
Earnest
href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List
href="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
(http://www.matronics.com/Navigator?AeroElectric-List)
(http://www.matronics.com/contribution)
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
Message 9
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Subject: | Re: LED Landing Lights |
JFTR...
Whelen shows LED landing lights in their current catalog...
Thanks!
Bill Denton
bdenton@bdenton.com
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Monday, April 21, 2008 8:32 AM
Subject: AeroElectric-List: Re: LED Landing Lights
<nuckolls.bob@cox.net>
At 08:59 AM 4/20/2008 -0700, you wrote:
>Stan,
>I've been watching the development of Landing Lights over the last several
>years as I build my Velocity. It used to be the cost of flying was enough
>to rationalize keeping on building rather than actually finishing and
>taking the plane out of the garage. Now it seems the advances in LED
>technology may be a new way to rationalize! I'm curious if you've lit
>these up yet and can give us an impression of how well they light compared
>to the other technologies out there (filament, halogen, HID, etc.). Can
>you give us a quick user report? What model are you using?
>
>Thanks,
>Dan
I'm not at liberty to speak to details but know that
the TC aircraft guys are presently evaluating LED
landing and taxi light products in a right-left
comparison of new and old technologies on existing
high-performance aircraft. When the go/no-go
decisions are made and they're ready to share
their findings, I'll let you all know.
At first blush, it's a no-brainer. Incandescent
lamps will soon be a thing of the past.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 10
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Subject: | Re: Non-tso altitude encoder, was Questions on avionics |
OC-
Thanks for answering the question before I could ask it!
Glen Matejcek
Message 11
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Subject: | Re: ELT Antenna for Fiberglass aircraft |
Good Morning Bruce,
Obsolete maybe, but I believe they will still meet federal requirements.
Is that not true?
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
628 West 86th Street
Downers Grove, IL 60516
630 985-8502
Stearman N3977A
Brookeridge Air Park LL22
In a message dated 4/18/2008 2:20:30 P.M. Central Daylight Time,
Bruce@glasair.org writes:
--> AeroElectric-List message posted by: "Bruce Gray" <Bruce@glasair.org>
I could be wrong but I don't think that dipole antennas are around for 406
MHTZ ELT's yet. They exist for 121.5 ELT's but they will be obsolete next
year.
Bruce
www.Glasair.org
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
Message 12
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Subject: | Re: Dual alternator single shunt |
Not sure I understand this point, Earnest. Is your shunt wired differently
than shown in Z-12, or the same?
Looking at Z-12, basically my proposal for a single shunt instead of two
would mean that the downstream side of both ANL/fusible links would be
connected to the shunt, instead of to the battery side of the starter
contactor. The other side of the shunt would then connect to the battery
side of the starter contactor. I don't see meaningful electrical difference
between that and the dual shunt circuit in Z-12. (Except obviously, with
just one "joint" shunt you can't discriminate between readings for the two
different alternators if they were ever run simultaneously, which mine won't
be.)
Ron
On Mon, Apr 21, 2008 at 7:01 AM, <MartinErni@aol.com> wrote:
> I put the starter ground on the same side of the shunt as the battery
> grounds. All other grounds attach to the other side of the shunt, so the
> answer is "no".
> Earnest
>
Message 13
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FOR SALE, RV6A 99% complete Except for engine. I had a heart attack, lost
medical. I completed the plane including a Chev V6 Vortec engine. I will
keep the engine for insurance reasons.
See attachment
Message 14
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Subject: | Re: Dual alternator single shunt |
I don't have z-12 handy so I couldn't say. Basically my starter ground
bypasses the shunt.
In a message dated 4/21/2008 1:31:38 P.M. Eastern Daylight Time,
rshannon@CRUZCOM.COM writes:
Not sure I understand this point, Earnest. Is your shunt wired differently
than shown in Z-12, or the same?
Looking at Z-12, basically my proposal for a single shunt instead of two
would mean that the downstream side of both ANL/fusible links would be connected
to the shunt, instead of to the battery side of the starter contactor. The
other side of the shunt would then connect to the battery side of the starter
contactor. I don't see meaningful electrical difference between that and the
dual shunt circuit in Z-12. (Except obviously, with just one "joint" shunt
you can't discriminate between readings for the two different alternators if
they were ever run simultaneously, which mine won't be.)
Ron
On Mon, Apr 21, 2008 at 7:01 AM, <_MartinErni@aol.com_
(mailto:MartinErni@aol.com) > wrote:
I put the starter ground on the same side of the shunt as the battery
grounds. All other grounds attach to the other side of the shunt, so the answer
is
"no".
Earnest
(http://www.matronics.com/Navigator?AeroElectric-List)
(http://www.matronics.com/contribution)
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
Message 15
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Subject: | Re: Dual alternator single shunt |
At 04:57 PM 4/20/2008 -0700, you wrote:
>My Murphy Rebel is going together with a slightly modified dual
>alternator, single battery Z-12 design. The primary alternator is the
>Jabiru 3300's integral 20A PM alternator. The second, backup only
>alternator is a manually switched B&C SD-20S. Except during very brief,
>momentary, preflight test switching perhaps, the two alternators will
>probably never be ON simultaneously.
>
>Due to various challenges, I'd like to use just one ammeter shunt to read
>output from both alternators, whichever is in use. However, that would
>require the shunt to be located downstream of the two independent
>ANL/fusible links, instead of upstream from the ANL/fusible links as shown
>in Z-12.
That' fine . . . .
>It appears to me there would be no significant electrical difference in
>having a single shunt downstream from the two ANL/fusible's compared to
>two shunts being upstream, as long as the single downstream shunt is big
>enough to take the output of both alternators if need be. Is that correct,
>or am I missing something?
That's correct.
Bob . . .
Message 16
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Subject: | Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 |
At 08:58 PM 4/20/2008 -0400, you wrote:
>I am in the process of completing the wiring design/effort on my homebuilt
>F1 Rocket and am "planning" on not using a battery bus, just a main and
>endurance buses. I'm using Z-13/8 (conventional mags), but don't see a
>need for a "keep alive" circuit with my avionics suite (not do I need
>power for an electronic ignition system). I see that other builders have
>put all sorts of things on their battery bus, such as flaps, clocks,
>etc. Since I may be missing something here, I'm asking: What does the
>"List" think ought to be on a "modern" battery bus and what rationale is
>commonly used to justify those selections, please...
What items do you want to run without having the battery
contactor closed? Unless you have an electrically dependent
engine, don't want courtesy lights, electric clocks, hour
meter that runs on oil pressure switch even if the master is
off . . . then perhaps you don't need a battery bus. Its
easy to add if you decide it's needed later.
Bob . . .
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At 07:06 PM 4/20/2008 -0700, you wrote:
>My blade fuse-style battery bus has these fused circuits:
>
>1) cabin dome lights
>2) the N/O oil pressure switch which feeds the Hobbes meter
>3) E-Bus alternate feed fuse
>4) low amperage (15A) ground power which goes to the battery, of course
Good . . .
>5) power for the over-voltage panel light so if everything suddenly goes
>dark due to an over voltage trip, I'll still have a clue what happened.
What item of equipment provides an ov trip indication?
What keeps this lead from draining the battery if it's
not on a charger?
>Any of those fuses could be handled by an inline fuse. I prefer having
>them securely mounted and organized on a fuse block where I can easily get
>to them. I have one more slot in the block, and will probably find
>something else to go there.
Sounds like a well considered and implemented
battery bus architecture.
Bob . . .
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Subject: | Re: Dual alternator single shunt |
At 08:35 AM 4/21/2008 -0400, you wrote:
>Will this position of the shunt cause any problems when the engine starter
>is engaged?? (as in peg the meter)
No . . .
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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Subject: | Re: Dual alternator single shunt |
At 10:01 AM 4/21/2008 -0400, you wrote:
>I put the starter ground on the same side of the shunt as the battery
>grounds. All other grounds attach to the other side of the shunt, so the
>answer is "no".
>Earnest
???? I think the question was about having two alternator
output leads share a common shunt where they feed the bus.
Contrary to a suggestion in the 'Connection about ground-side
shunts, it's not a good idea and will be eliminated in
Revision 12.
Bob . . .
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Subject: | Re: Dual alternator single shunt |
Which is not a good idea "ground-side shunts or 2 alt leads sharing a common
shunt"? Could you elaborate?
Earnest
In a message dated 4/21/2008 9:45:45 P.M. Eastern Daylight Time,
nuckolls.bob@cox.net writes:
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<nuckolls.bob@cox.net>
At 10:01 AM 4/21/2008 -0400, you wrote:
>I put the starter ground on the same side of the shunt as the battery
>grounds. All other grounds attach to the other side of the shunt, so the
>answer is "no".
>Earnest
???? I think the question was about having two alternator
output leads share a common shunt where they feed the bus.
Contrary to a suggestion in the 'Connection about ground-side
shunts, it's not a good idea and will be eliminated in
Revision 12.
Bob . . .
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
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Subject: | Re: Dual alternator single shunt |
I just have to ask ....
If you use a shunt that "sees" all current flowing from the battery and the
starter draws 200a, doesn't that hit the 50ma ammeter (if using a 40a shunt)
with 250ma?? Doesn't seem like that would do the ammeter any good...
I must be missing something about this... sorry..
Dave
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
Sent: Monday, April 21, 2008 9:39 PM
Subject: Re: AeroElectric-List: Dual alternator single shunt
> <nuckolls.bob@cox.net>
>
> At 08:35 AM 4/21/2008 -0400, you wrote:
>
>>Will this position of the shunt cause any problems when the engine starter
>>is engaged?? (as in peg the meter)
>
> No . . .
>
>
> Bob . . .
>
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Subject: | Re: Dual alternator single shunt |
Take a look at Z-12. As is the case in most all of Bob's schematics (I
think) the shunt is in series with the alternator output, which connects to
the upstream side of the starter contactor. The starter motor current goes
through the starter contactor. That heavy current does not split off to the
side, through the alternator. In that position the shunt senses the output
of the alternator.
Ron
On Mon, Apr 21, 2008 at 7:58 PM, David & Elaine Lamphere <lamphere@vabb.com>
wrote:
> lamphere@vabb.com>
>
> I just have to ask ....
>
> If you use a shunt that "sees" all current flowing from the battery and
> the starter draws 200a, doesn't that hit the 50ma ammeter (if using a 40a
> shunt) with 250ma?? Doesn't seem like that would do the ammeter any good...
>
> I must be missing something about this... sorry..
>
> Dave
>
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>
> At 07:06 PM 4/20/2008 -0700, you wrote:
>
> My blade fuse-style battery bus has these fused circuits:
> >
> > 1) cabin dome lights
> > 2) the N/O oil pressure switch which feeds the Hobbes meter
> > 3) E-Bus alternate feed fuse
> > 4) low amperage (15A) ground power which goes to the battery, of course
> >
>
> Good . . .
>
> 5) power for the over-voltage panel light so if everything suddenly goes
> > dark due to an over voltage trip, I'll still have a clue what happened.
> >
>
> What item of equipment provides an ov trip indication?
> What keeps this lead from draining the battery if it's
> not on a charger?
I later corrected my (silly) statement that I had the OV warn light on the
battery bus (#5 above) in a later post, where i changed the subject from
"Digest..." to "why a battery bus" so it would make a little more sense (the
subject, not my error!) When I listed OV warn, I must have been suffering
from some sort of acute brain fade, or worse, I guess. My alternator warn
light is powered through the main bus, of course.
>
>
> Any of those fuses could be handled by an inline fuse. I prefer having
> > them securely mounted and organized on a fuse block where I can easily get
> > to them. I have one more slot in the block, and will probably find something
> > else to go there.
> >
>
> Sounds like a well considered and implemented
> battery bus architecture.
>
> Bob . . .
At least as corrected. Thanks.
Ron
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Subject: | Pinout for Softcom ATC-P and Website Maintenance |
At 06:33 AM 4/20/2008 -0700, you wrote:
>On 04/20/2008 05:59 Robert L. Nuckolls, III wrote:
>
> > I've worked on it a bit in Photoshop and enhanced the
> > readability a tad. It has been posted to:
> >
> > http://www.aeroelectric.com/Installation_Data/ATC-2P_Schematic.gif
>
>
>Very good, Bob. I'm sure members of the community will be grateful for
>it, as I have been for other materials you've provided over the years.
>
>Alas, the URL for the schematic (above) gives a "403 error". Perhaps
>the fix is as simple as giving the file read permissions for everyone.
>
>Best,
>Joe (K7JD)
>http://www.mail2600.com/Airplane
Thanks for the head's up on it Joe . . . your hypothesis
was correct. I didn't set the permissions after uploading.
On the topic of website maintenance, what started out
many moons ago as an eclectic collection of occasional
tidbits interesting to the OBAM aviation community to a rather
large body of work.
It's become so large that I'm having trouble keeping track
of what's posted where and why. A couple of weeks ago I
began a reorganization effort that will include sorting
of information into categories and a comprehensive linked
table of contents that will aid both the manager (me) and
the readers (you folks) in accessing what's available.
I think I've got a couple more days worth of work to go
but it's shaping up nicely. When the new organization is
posted, I'll have to rely on all of you good folks to
sift the sands of reorganization and letting me know
where a link or permission didn't get handled properly.
One example of the "new look" is already posted
at:
http://aeroelectric.com/Mfgr_Data.html
I have similar index pages being crafted for all
the articles.
On the topic of manufacturer's data, if any of you
possess operation, installation and/or maintenance
data on various bits of hardware that you can scan
(preferably into pdf files) and forward to me, I'll
have a better place to post such items and support
the efforts of our brothers.
Finally, I'd like to re-enforce the notion that the
website is not intended to be the gospel according
to Bob Nuckolls but a gathering place for sharing
the best we know how to do. If any of you have a
process or technique that seems particularly elegant
and you would like to share it, please feel encouraged
to write it up, take photos, etc. and forward to me.
I'll help with editing, captioning, formating and
of course, getting it posted.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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Subject: | Re: A Bit of Help, Please |
Bob,
Your analysis of my situation was dead on accurate. And your info was
invaluable.
I sincerely appreciate your response!
Stan Sutterfield
>Bob,
>Thanks for your robust reply. Very helpful.
>My intention is to prevent reverse current flow in certain conditions.
>I connected the zener diodes in line where needed and did a test of the
>system and the diodes did stop the reverse flow of current - as
>desired. My concern was that the selected diodes (RS INT4742A - RS part
>number 276-563) may not be robust enough to stop the 0.9 Amp current over
>the long term.
That's what I understood. I was mystified by the
use of a zener diode. These will "stop reverse flow"
only if the voltage remains below the rating
at which reverse flow is desired and expected . . .
in the case of the 1N4742, 12 volts.
The "ratings" numbers for these devices are
given in there reverse current flow mode of
operation where they dissipate higher power
for the same current flow. Since this package
is generally good for about 1W of dissipation,
their max reverse current should be limited to
about 1w/12v = 0.08 amps. The 0.02 amps you cited
was the "test current" at which the 12v regulation
accuracy was given . . . not the operating
current where the current is dissipation limited.
You're using these devices in their forward
conduction mode where voltage drop is not related
to the zener voltage rating of the device, i.e.
12v but the forward conduction rating which is on
the same order as the ordinary silicon diode
rectifier of about 0.8 volts. Here the same
dissipation limits apply . . . but to get 1w
of heat out of it in the forward mode, you can
now force 1.2a through the device. MUCH larger
than any of the reverse current ratings given
in the 1N4742 data sheet . . . because folks
are generally expect to use theses as reverse
current regulators, not forward current
power steering devices.
http://en.wikipedia.org/wiki/Zener_diode
This is why the 1N4742 didn't smoke during your
extended bench test . . . you were not using it
in the manner described in the data sheets hence
non-hazardous dissipated power at higher than "rated"
currents.
>I may as well insert the correct diodes now rather than redo the work at a
>later time. So, it sounds like I should change the diodes to another type
>or another rating. Correct? Perhaps the 1N5400 series would be best.
The significance of my earlier posting was that
mis-application of the zener as a power steering
device was marginally satisfactory given that
voltages in your system are expected to exceed
the 12v rating of the device whereupon some amount
of reverse current may flow under conditions where
you don't want it to happen. If you picked a zener
that was larger, say 16v or even higher, then
it could be expected to function as you intended
even if it wasn't exactly the right part for the
job.
The silicon rectifier also has a voltage rating
stated as a limit. See:
http://www.diodes.com/datasheets/ds28002.pdf
Note that these little critters are the same
physical size as the 1N4742 but have voltage
limits ranging from 50 to 1000v. Any of these
devices could be used in your application. I
suggested the 5400 series devices be considered
also:
http://www.diodes.com/datasheets/ds28007.pdf
These to are offered in the same ranges of
voltage limits as the 4000 series devices and
while electrically much larger than you need in
this particular case, there's no great transgression
in using such devices at much lower levels
than their rated limits.
In this case, I favor the 5400 series devices
for their mechanical robustness. Larger package,
larger leadwires, much easier to work with in
these situations and less likely to be damaged in
service due to handling.
I think you got sucked into the 12v zener
selection due to a mis-understanding of its
rating as being "appropriate" to your 14v
airplane. The problem was that zeners are
not intended for or generally used as reverse
power blocking devices. The silicon rectifiers
come with lots larger voltage LIMIT ratings
so while much larger than the system voltage
of your aircraft, they are not being mis-applied
by using say a 600v device in your 14v
airplane.
So yes, my recommendation is that you avail yourself
of Radio Shack's standard inventory and substitute
any one of the 5400 series devices for the 1N4742
in the application you've described.
Bob . . .
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
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Subject: | Re: LED Landing Lights |
Dan,
I'd be happy to give you my impressions on using LEDs for landing lights.
I've done a number of experiments over the past 2 years with various LEDs up
to 1W. There are now much larger wattage LEDs (3W, 5W) available that
provide greater illumination, so my info is a bit dated. The technology gains
in
the LED industry is literally changing daily.
I don't have all the technical data, but rather will tell you in layman's
terms what I've discovered.
In short, LEDs are not yet ready for prime time as landing lights - although
they are getting very close. Several applications of LED headlights are in
use in 2008 automobiles, but I have not witnessed the performance of those
lights. I do know they are using optics similar to projection-type lights to
focus the LED emissions in order to get suitable illumination. Whelen had
some 12 LED landing lights at Sun n Fun, but to get illumination close to
halogens, they have to narrowly focus the beam (10 degrees, I think) which means
you get little side illumination which is needed at night in order to have the
peripheral vision needed to recognize sink rate in the landing flare.
However, although not ready as landing lights, I believe LEDs are quite up to
the
task as taxi or recognition lights. Peripheral vision is not as critical when
taxiing and furthermore, LEDs can be used in a wider beam which does not
project as far.
I bought the AeroSun 800 LED lights and found them suitable only as
taxi/recognition lights. I don't intend to use them because they are heavy and
the
dimensions are twice as large as I can fit in my airplane. I bought the
Whelen Model 71125 LED light to use as taxi-recognition lights. I have a steady
on in one switch position and flashing (using Eric Jones' wig wag) in the
other position.
I believe that, at this time, LEDs are suitable for taxi illumination and
for recognition lights. As recognition lights, the square wave light emission
is easily recognized by the eye. The temperature of the light emission is
close to daylight (the yellow emission of halogen is easier to see in daylight
conditions), however the square wave pattern mitigates the tendency of the
light to blend into daylight.
I have a short report and photos of the AeroSun 800 lights on my web site at
_http://www.rv-8a.net/2008.htm_ (http://www.rv-8a.net/2008.htm) on 6 Mar
08. You can see the Whelen LEDs I bought on the same page if you scroll down
to 12 Apr 08.
I am completely sold on using LEDs for the position lights. Since they
simply have to radiate and not illuminate, LEDs are ideal for position lights.
I've been complaining at Whelen to bring out 12v LED position lights and they
finally did it. They consume only 0.25A, so three would be only 0.75A. I
strongly recommend using LEDs for position lights.
I believe you are wise to wait a bit longer to decide which LED light to
use. I am convinced that LEDs will be able to provide illumination suitable for
use as a landing light in the near future.
If you have additional questions, feel free to contact me offline.
Stan Sutterfield
_www.rv-8a.net_ (http://www.rv-8a.net)
Stan,
I've been watching the development of Landing Lights over the last several
years
as I build my Velocity. It used to be the cost of flying was enough to
rationalize
keeping on building rather than actually finishing and taking the plane
out of the garage. Now it seems the advances in LED technology may be a new
way to rationalize! I'm curious if you've lit these up yet and can give us
an
impression of how well they light compared to the other technologies out
there
(filament, halogen, HID, etc.). Can you give us a quick user report? What
model are you using?
Thanks,
Dan
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
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Lee,
I'm not building in a battery bus either. I don't need it. The only thing
that needs a battery bus on my plane is a GPS antenna keep alive. With it,
the GPS locks on in 10 seconds. Without it, it locks on in 30 seconds.
Stan Sutterfield
I am in the process of completing the wiring design/effort on my homebuilt
F1 Rocket and am "planning" on not using a battery bus, just a main and
endurance buses. I'm using Z-13/8 (conventional mags), but don't see a need
for a "keep alive" circuit with my avionics suite (not do I need power for
an electronic ignition system). I see that other builders have put all
sorts of things on their battery bus, such as flaps, clocks, etc. Since I
may be missing something here, I'm asking: What does the "List" think ought
to be on a "modern" battery bus and what rationale is commonly used to
justify those selections, please...
Regards,
Lee...
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
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Lee,
A slight correction. While I don't have a battery bus, I do have a fused
wire from the hot battery terminal that powers my dimmer-controlled interior
LED lights.
Stan Sutterfield
I am in the process of completing the wiring design/effort on my homebuilt
F1 Rocket and am "planning" on not using a battery bus, just a main and
endurance buses.
**************Need a new ride? Check out the largest site for U.S. used car
listings at AOL Autos.
(http://autos.aol.com/used?NCID=aolcmp00300000002851)
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