Today's Message Index:
----------------------
1. 05:45 AM - H10-40 Headsets for sale (Stucklen, Frederic IFC)
2. 06:28 AM - Re: Faston Terminals on 7.2 ah Aux Battery (Robert L. Nuckolls, III)
3. 06:41 AM - Instrument cutouts (Neville Kilford)
4. 07:02 AM - Cell Phone Headset Adapter (Jon Finley)
5. 07:05 AM - big wire terminations (Paul Wilson)
6. 07:17 AM - Re: AOA//LED's for cockpit (Paul Messinger) (Greg Campbell)
7. 08:16 AM - Re: Instrument cutouts (Kevin Horton)
8. 08:27 AM - ground plane (Kenneth Melvin)
9. 09:43 AM - Re: ground plane (richard@riley.net)
10. 09:54 AM - Re: big wire terminations (Robert L. Nuckolls, III)
11. 09:56 AM - Re: Auxiliary Electrical System (Robert L. Nuckolls, III)
12. 09:58 AM - Re: Instrument cutouts (Pete Waters)
13. 10:22 AM - Re: ground plane (Gilles.Thesee)
14. 12:02 PM - Re: ground plane (Robert L. Nuckolls, III)
15. 12:24 PM - Re: Re: Z-14 with two rear batteries (Robert L. Nuckolls, III)
16. 04:33 PM - Tach sensor (irampil@notes.cc.sunysb.edu)
17. 05:33 PM - Re: Re: Z-14 with two rear batteries (John Schroeder)
18. 06:26 PM - Re: Re: Z-14 with two rear batteries (Robert L. Nuckolls, III)
19. 07:47 PM - Re: ground plane (Kenneth Melvin)
20. 07:47 PM - Re: ground plane (Kenneth Melvin)
21. 07:47 PM - Re: ground plane (Kenneth Melvin)
22. 08:46 PM - Re: Instrument cutouts (Alex Peterson)
23. 09:22 PM - Connecting Whelen Strobes (Larry Bowen)
Message 1
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| Subject: | H10-40 Headsets for sale |
--> AeroElectric-List message posted by: "Stucklen, Frederic IFC" <Fred.Stucklen@UTCFuelCells.com>
Listers,
I have two H10-40 headsets that I am no longer using, and would like to
sell. Both are a few years old, but in excellent condition. One has a head
pad and gel ear muffs. Both have foam mike filters.
I'm asking $150.00 each, or $275.00 for both. Anybody interested should
contact me off the list at the email address below.
Fred Stucklen
RV-6A N926RV 54 Hrs
fred.stucklen@utcfuelcells.com
Message 2
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| Subject: | Re: Faston Terminals on 7.2 ah Aux Battery |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 05:14 PM 9/23/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Pat Hatch" <pat_hatch@msn.com>
>
>Bob,
>
>I am using the 7.2 ah aux batt from B & C on Z-14, coupled with the 20 amp
>vac pad alternator.
>
>I am trying to figure out how to terminate the #4 AWG wires to plug into
>the Faston terminals of the battery. Any suggestions?
Sure, as a general rule, any battery fitted with fast-on
terminals is incapable of delivering a discharge current
worthy of 4AWG wire . . . with a few exceptions. I believe
I've seen some of the very popular 17 a.h. size batteries
optionally offered with both bolt-on posts -OR-
1/4" fast-ons . . . obviously this battery is capable of
such currents but would probably burn the tabs off if
you loaded it that hard.
Keep in mind that the Z-drawings are exemplar documents
that suggest wire sizes based on certain variables . . . these
may change under various conditions. For example:
Rear mounted batteries get fatter wires to offset
voltage drop considerations. Small batteries used
primarily to stabilize and alternator and perhaps
provide momentary support for accessories not
designed to live in real world (FADEC and some
EFIS systems) might have fast-on tabs and will
use smaller wire. In the case of 1/4" fast-on
fitted batteries, 10AWG wire can be crimped
into a yellow 1/4" fast-on terminal. If this
battery is supported only by a small alternator
(SD-8 or SD-20) then all "fat" wires in the
smaller system can be downsized to 10 (SD-20)
or 12AWG (SD-8).
If you're contemplating installation of a
battery with 1/4" fast-on terminals wherein
starter current may flow from this battery,
you need to get a battery with better terminals.
Even if you don't expect to use the smaller battery
for starting, an overly robust wire on a 1/4"
terminal offers unnecessary vibration stresses
to this terminal. Battery to contactor and battery
to ground jumpers are generally short and can be
mechanically undersized to enhance vibration
resistance (B&C offers 4AWG battery jumpers
which are useful even in systems where the long
battery feeds are 2AWG).
There are a few small batteries capable of engine
cranking currents and have appropriately sized,
threaded terminals. See B&C catalog for latest
offerings.
Bob . . .
Message 3
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| Subject: | Instrument cutouts |
--> AeroElectric-List message posted by: "Neville Kilford" <nkilford@etravel.org>
I'd like to proceed with the panel wiring & plumbing etc, and then slot in
flight instruments at the last minute (i.e. in about a year's time) but I'm
rather nervous about cutting holes and then discovering that the instruments
I buy (esp. gyros) don't fit, e.g. if I've cut the holes too close together.
Can anyone recommend a spacing for instruments, or make any other suggestions
for this?
Many thanks in anticipation.
Nev
--
Jodel D-150 in progress
UK
Message 4
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| Subject: | Cell Phone Headset Adapter |
--> AeroElectric-List message posted by: "Jon Finley" <jon@finleyweb.net>
Hi all,
I've seen the archived discussion regarding the legality/usefulness of
using a cell phone in an airplane.
My question is: Is there an easy way to make a cell phone adapter for
aviation headsets/intercom? If so, what is it (diagram perhaps??)? Is
using one of the premade versions like SafetyCell
(http://www.mypilotstore.com/MyPilotStore/sep/1767) the best way to go
(it seems kinda pricey).
Thanks!
Jon Finley
N90MG Q2 - Subaru EJ-22 DD - 455 Hrs. TT - 3.5 Hrs Engine
Apple Valley, Minnesota
http://www.FinleyWeb.net/default.asp?id=96
Message 5
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| Subject: | big wire terminations |
--> AeroElectric-List message posted by: Paul Wilson <pwilson@climber.org>
Bob,
I have misplaced the link for the DIY attachment of the lugs on big wires. Can
you provide the link?
Thanks, Paul
Message 6
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| Subject: | Re: AOA//LED's for cockpit (Paul Messinger) |
--> AeroElectric-List message posted by: "Greg Campbell" <GregCampbellUSA@earthlink.net>
If you don't have time to build the "vane type" AOA described,
you might consider the Rite Angle IIIb from EMAviation.
Check out www.RiteAngle.com then click on "Angle of Attack System Info".
For $545 + $50 for the flap option (necessary in my opinion if you have flaps).
The display is a simple row of color coded LED's - you can mount one or two of
them.
One idea was to put them in the glare shield so they reflect off the windshield
like a HUD.
Bob mentioned "piecemeal development"...
+ Flap position compensation for an additional $50 - includes flap position indicator
LEDs
+ Gear warning option for $40 - includes MAP switch for throttle position
+ Automatic and manual LED dimming
+ Audio warnings, adjustable volume
+ Optional second display or high intensity LEDs.
+ Automatic Power Supply from aircraft and/or separate batteries.
+ Simple programmer box - easy calibration.
Anyway - for not much more than the cost of the components to DIY,
you can get a system that's proven and ready to install.
I'm in the process of installing one - so I'll let you know
how it works. So far - the components and design are nice.
Greg Campbell
Lancair ES 75%
Message 7
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| Subject: | Re: Instrument cutouts |
--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
>--> AeroElectric-List message posted by: "Neville Kilford"
><nkilford@etravel.org>
>
>I'd like to proceed with the panel wiring & plumbing etc, and then slot in
>flight instruments at the last minute (i.e. in about a year's time) but I'm
>rather nervous about cutting holes and then discovering that the instruments
>I buy (esp. gyros) don't fit, e.g. if I've cut the holes too close together.
>
>Can anyone recommend a spacing for instruments, or make any other suggestions
>for this?
>
>Many thanks in anticipation.
>
>Nev
>
>--
>Jodel D-150 in progress
>UK
I see two options:
1. Decide exactly which manufacturer and model instruments you will use,
then get the dimensions from them.
2. Use 3 5/8" spacing, which should be safe for the popular items.
Kevin Horton
Message 8
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--> AeroElectric-List message posted by: Kenneth Melvin <melvinke@direcway.com>
When fitting a transponder antenna ground plane in a composite airplane, does
the shape of the metal plate matter? Is a rectangle as good as a circle if the
area is the same?
Kenneth Melvin
Message 9
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| Subject: | Re: ground plane |
--> AeroElectric-List message posted by: richard@riley.net
At 08:24 AM 9/24/03 -0700, you wrote:
>--> AeroElectric-List message posted by: Kenneth Melvin
><melvinke@direcway.com>
>
> When fitting a transponder antenna ground plane in a composite airplane,
> does the shape of the metal plate matter? Is a rectangle as good as a
> circle if the area is the same?
>Kenneth Melvin
From Jim Wier, on rec.aviation.homebuilt
=============
Think of an aluminum pie pan after you've eaten the
pie. Circular, about 6" in diameter (I eat small pies). Anyway, you've
got a disk of thin aluminum after you cut the bent-up edges of the pie pan
off about 5.5 inches in diameter. Poke a 3/8" hole in the dead center of
that aluminum disk, mount the little transponder antenna (the one with the
little b-b on the top of the rod) and connector in the hole, point the rod
DOWN towards the ground, and away you go.
Some considerations:
1. It doesn't have to be circular. It can be square, elliptical,
hexagonal, or an old stop sign. What IS important is that there MUST be
equal metal on all sides of the radiating rod. What is ALSO important is
that there must be some place on every edge that is 2.75" away from the
center of the hole. Get it? If you do a SQUARE, make sure that you
average the side length versus the hypotenuse so that somewhere along each
edge there is a 2.75" length of metal from the center of the hole.
2. It doesn't have to be grounded to anything else in the airplane EXCEPT
the shield of the coax running to the transponder. It CAN be grounded if
you want, but it is not necessary.
3. It can be anything from one mil tinfoil to armor plate thick and it
won't work any better or worse. Me? I use an old scrap of PC board for
the plain and simple reason that I can SOLDER the connector to the copper
foil and not have to ever worry about corrosion getting between the
connector and the ground plane.
4. Put a piece of metal -- tinfoil to armor plate -- between the antenna
and the "sensitive" parts of your anatomy. Think about putting your fanny
in a microwave oven and the consequences thereof. Don't worry about your
head. If we all had any brains we'd be out chasing women instead of
messing with airplanes anyway.
5. In an airplane where it doesn't stick out into the slipstream and
create drag, the little "b-b rod" antenna works every bit as well as the
expensive blade. Save your money and get more avionics instead of wasting
it on blade antennas. I know this little avionics company in Grass
Valley...{;-)
Jim
Message 10
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| Subject: | Re: big wire terminations |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:09 AM 9/24/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: Paul Wilson <pwilson@climber.org>
>
>Bob,
>I have misplaced the link for the DIY attachment of the lugs on big wires.
>Can you provide the link?
> Thanks, Paul
http://www.aeroelectric.com/articles/big_term.pdf
Message 11
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| Subject: | Re: Auxiliary Electrical System |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:32 PM 9/23/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Paul" <list@incont.com>
>
>I have a '54 Cessna 170B with a C145-2 Engine and 60Amp Ford
>alternator (14V system). I would like to remove the venturii's
>(2) and go to a secondary electrical system with enough power to
>run an electric directional gyro, artificial horizon and a Garmin
>300XL GPS/COM for up to 4 hours. Any suggestions? THANKS, Paul
Talk to B&C at 316.283.8000 and see what their recommendations
are for your particular situation. If your airplane were OBAM
it would be easy but you'll need to arm-wrestle with the FAA
over any choices you make . . . Bill will have some recommendations
in this regard.
Bob . . .
Message 12
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| Subject: | Re: Instrument cutouts |
--> AeroElectric-List message posted by: Pete Waters <pedroagua@yahoo.com>
The last page of the "Instruments" section of the Aircraft Spruce catalog has instrument panel templates. Copy the page, cut out the templates onto cardboard, and play jigsaw-puzzle games on your panel before cutting. Also, you can lay out the panel digitally using the graphics tool at www.epanelbuilder.com, although that doesn't give you precise dimensions.
Pedro
Kevin Horton <khorton01@rogers.com> wrote:
--> AeroElectric-List message posted by: Kevin Horton
>--> AeroElectric-List message posted by: "Neville Kilford"
>
>
>I'd like to proceed with the panel wiring & plumbing etc, and then slot in
>flight instruments at the last minute (i.e. in about a year's time) but I'm
>rather nervous about cutting holes and then discovering that the instruments
>I buy (esp. gyros) don't fit, e.g. if I've cut the holes too close together.
>
>Can anyone recommend a spacing for instruments, or make any other suggestions
>for this?
>
>Many thanks in anticipation.
>
>Nev
>
>--
>Jodel D-150 in progress
>UK
I see two options:
1. Decide exactly which manufacturer and model instruments you will use,
then get the dimensions from them.
2. Use 3 5/8" spacing, which should be safe for the popular items.
Kevin Horton
---------------------------------
Message 13
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| Subject: | Re: ground plane |
--> AeroElectric-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
----- Message d'origine -----
De : "Kenneth Melvin" <melvinke@direcway.com>
: <aeroelectric-list@matronics.com>
Envoy : mercredi 24 septembre 2003 17:24
Objet : AeroElectric-List: ground plane
> --> AeroElectric-List message posted by: Kenneth Melvin
<melvinke@direcway.com>
>
> When fitting a transponder antenna ground plane in a composite airplane,
does the shape of the metal plate matter? Is a rectangle as good as a circle
if the area is the same?
> Kenneth Melvin
>
Kenneth,
My understanding is as follows :
-The radius of a circular plate must be 1/4 wave.
- The DIAGONAL of a a square-rectangle must be 1/4 wave.
- The ground plane may bend away from the antenna.
Hope this helps,
Gilles Thesee
Message 14
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| Subject: | Re: ground plane |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:24 AM 9/24/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: Kenneth Melvin
><melvinke@direcway.com>
>
> When fitting a transponder antenna ground plane in a composite airplane,
> does the shape of the metal plate matter? Is a rectangle as good as a
> circle if the area is the same?
>Kenneth Melvin
You'll get a number of answers to this . . . some will include
words like "must", "should" and "shall" . . .
From the best of all worlds perspective, a 1/4 wave monopole
antenna (like transponder and DME antennas) perform best when
operated against a "ground plane" . . . the ideal ground plane
extends to the horizon in all directions. Practical ground planes
are much smaller . . . in fact, it takes good test equipment to
measure the difference between an infinite ground plane and one
that is fabricated from an infinite number of 1/4 wave monopole
antennas radiating out from the base of the antenna in a disk
shaped plane . . .
Given that a transponder antenna is 2.65" tall, the ideal tuned
ground plane has a RADIUS of 2.65" or 5.3" DIAMETER.
This configuration yields an antenna system with a feedpoint
impedance somewhat less than the ideal 50 ohms . . . so if you
wanted to get really pedantic about it, the radial plane can
be drooped away from the antenna (becoming cone shaped) by
an amount necessary to raise the nominal 30 ohm feedpoint up
to 50 ohms . . . needless to say, we don't see many transponder
antennas on airplanes with conical groundplanes under them. We
OFTEN see fixed antennas on airport buildings with drooped radials.
Airborne radio communications extends only to
the relatively nearby horizon, so most radios would perform
adequately using a wet string for an antenna. Well, perhaps
something a little better than wet string . . . but
it is sufficient to say that poor radio performance on an
airplane is seldom a function of marginal antenna design.
Bottom line is that if you have a hunk of scrap around the
shop from which you can cut a 5.3" disk, fine. If you have
a weirdly-shaped hunk of .08" scrap (too heavy to use snips
and you don't have a bandsaw) with one dimension over 5",
you can use that too and you're never going to know the
difference. Needless to say, if the ground plane is something
other than flat, the un-flatness will do you the most
good if it moves away from the antenna. The "magic"
isn't area but distance from the center. We often see
building mounted antennas with four radially positioned
conductors as a ground plane. These are known to perform
within a few percent of the capability of a full disk
tuned ground plane which is almost indistinguishable from
the ideal infinite ground plane.
Bob . . .
Message 15
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| Subject: | Re: Z-14 with two rear batteries |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:20 PM 9/23/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Dan O'Brien" <danobrien@cox.net>
>
>
>Bob,
>
>I have a few questions about your drawing of Z-14 with two rear-mounted
>batteries, which you posted at
><http://www.aeroelectric.com/articles/Appendix_Z_Drawings/Z-14_Rear_Bats.pdf>http://www.aeroelectric.com/articles/Appendix_Z_Drawings/Z-14_Rear_Bats.pdf.
>
>You indicate that the connection from the crossfeed contactor to the
>starter and the main alternator current limiter should be a copper/brass
>strap, .032" by .70". First, for educational purposes, what is the purpose
>for this strap rather than, say, 2 AWG wire? Second, can one substitute,
>say, 2AWG wire, welding wire, etc.? Third, if the strap is best, where can
>it be obtained?
It is often very useful to mount high current
components right next to each other. In some of my
drawings I show the ANL fuse holder, starter contactor
and crossfeed contactors mounted right next to each other.
It's difficult and ugly to put terminals on very short
pieces of fat wire to make up connections between
these components. Strips of copper or brass can be bent
and drilled to provide nice conducting straps that
have no joints, are easy to fabricate and will make
a VERY compact installation compared to the use of wire
and terminals.
Building suppliers have flashing copper. Hobby shops and
hardware stores stock KS Engineering hobby materials.
http://www.ksmetals.com/
http://www.ksmetals.com/HobbyMerchandisers/structural_sheet.asp
See if a local hobby shop or hardware store can
sell you a 6" x 12" x 0.32" copper sheet.
If push comes to shove, you can order off the 'net
One source is Tower Hobbies at
http://www2.towerhobbies.com/cgi-bin/WTI0091P?&C=RDB&V=K+S
Where we see a listing for CS32 copper sheet (3 sheets
for $25). A local store can sell you one sheet from
their display case.
Bob . . .
Message 16
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09/24/2003 07:33:11 PM,
Serialize complete at 09/24/2003 07:33:11 PM
--> AeroElectric-List message posted by: irampil@notes.cc.sunysb.edu
Does anyone have experience with the Westach 720-4a proximity sensor
used as a prop tachometer. I was planning to mount it behind (and in
proximity to)
the 6 radial bolts attaching my Rotax to my Airmaster. I was planning on
using
its output to drive a BMA EFIS/1. There seems to be be very little info
on the web about it.
Ira N224XS
Back from Upholstery, Panel mounted, Prop hub mounted :-)
Message 17
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| Subject: | Re: Z-14 with two rear batteries |
--> AeroElectric-List message posted by: John Schroeder <jschroeder@perigee.net>
Bob -
In the file below, you show the crossfeed contactor on the firewall with
the starter and alternator B-leads. In a previous discussion regarding Z-
14, you recommended that the crossfeed contactor be in the rear with the
batteries. We are about to start the wiring with 4 contactors in the rear
(ground power contactor feeding #2 battery contactor and the crossfeed
contactor tying the #1 battery contactor to the the # 2 battery contactor.
Any reason not to go this way?
Thanks,
John Schroeder
Lancair Super ES
> <http://www.aeroelectric.com/articles/Appendix_Z_Drawings/Z-
> 14_Rear_Bats.pdf
Message 18
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| Subject: | Re: Z-14 with two rear batteries |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:32 PM 9/24/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: John Schroeder
><jschroeder@perigee.net>
>
>Bob -
>
>In the file below, you show the crossfeed contactor on the firewall with
>the starter and alternator B-leads. In a previous discussion regarding Z-
>14, you recommended that the crossfeed contactor be in the rear with the
>batteries. We are about to start the wiring with 4 contactors in the rear
>(ground power contactor feeding #2 battery contactor and the crossfeed
>contactor tying the #1 battery contactor to the the # 2 battery contactor.
>
>Any reason not to go this way?
>
>Thanks,
>
>John Schroeder
>Lancair Super ES
> > <http://www.aeroelectric.com/articles/Appendix_Z_Drawings/Z- >
> 14_Rear_Bats.pdf
What size are your batteries? Do you intend to crank with
both batteries? If they are both capable of and will
be used to crank, then I prefer to put the crossfeed contactor
on the firewall so that it can be power distribution point from
each battery to its respective bus and terminate one end of
the feed to starter.
If the aux battery is small and will not be used to crank,
then the crossfeed contactor can be relatively small . . .
Like and S704-1 relay as opposed to an S701-1 contactor.
Here the relay is a poor terminal block for fat wires
so the notion of putting it on the firewall has no
mechanical value for gathering fat wires together so
one could consider putting it back next to the batteries.
Personally, I like the S701-2's ability to provide both
crossfeed function and serve as a distribution point
for the suite of system feedwires . . . If you've
got a substantial aux alternator (SD-20 or larger)
then S701-2 on the firewall would be my contactor
style and location of choice.
Bob . . .
Message 19
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| Subject: | Re: ground plane |
--> AeroElectric-List message posted by: Kenneth Melvin <melvinke@direcway.com>
As ever, the definitive answer. Thanks Bob.
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: ground plane
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 08:24 AM 9/24/2003 -0700, you wrote:
> >--> AeroElectric-List message posted by: Kenneth Melvin
> ><melvinke@direcway.com>
> >
> > When fitting a transponder antenna ground plane in a composite
airplane,
> > does the shape of the metal plate matter? Is a rectangle as good as a
> > circle if the area is the same?
> >Kenneth Melvin
>
> You'll get a number of answers to this . . . some will include
> words like "must", "should" and "shall" . . .
>
> From the best of all worlds perspective, a 1/4 wave monopole
> antenna (like transponder and DME antennas) perform best when
> operated against a "ground plane" . . . the ideal ground plane
> extends to the horizon in all directions. Practical ground planes
> are much smaller . . . in fact, it takes good test equipment to
> measure the difference between an infinite ground plane and one
> that is fabricated from an infinite number of 1/4 wave monopole
> antennas radiating out from the base of the antenna in a disk
> shaped plane . . .
>
> Given that a transponder antenna is 2.65" tall, the ideal tuned
> ground plane has a RADIUS of 2.65" or 5.3" DIAMETER.
>
> This configuration yields an antenna system with a feedpoint
> impedance somewhat less than the ideal 50 ohms . . . so if you
> wanted to get really pedantic about it, the radial plane can
> be drooped away from the antenna (becoming cone shaped) by
> an amount necessary to raise the nominal 30 ohm feedpoint up
> to 50 ohms . . . needless to say, we don't see many transponder
> antennas on airplanes with conical groundplanes under them. We
> OFTEN see fixed antennas on airport buildings with drooped radials.
>
> Airborne radio communications extends only to
> the relatively nearby horizon, so most radios would perform
> adequately using a wet string for an antenna. Well, perhaps
> something a little better than wet string . . . but
> it is sufficient to say that poor radio performance on an
> airplane is seldom a function of marginal antenna design.
>
> Bottom line is that if you have a hunk of scrap around the
> shop from which you can cut a 5.3" disk, fine. If you have
> a weirdly-shaped hunk of .08" scrap (too heavy to use snips
> and you don't have a bandsaw) with one dimension over 5",
> you can use that too and you're never going to know the
> difference. Needless to say, if the ground plane is something
> other than flat, the un-flatness will do you the most
> good if it moves away from the antenna. The "magic"
> isn't area but distance from the center. We often see
> building mounted antennas with four radially positioned
> conductors as a ground plane. These are known to perform
> within a few percent of the capability of a full disk
> tuned ground plane which is almost indistinguishable from
> the ideal infinite ground plane.
>
> Bob . . .
>
>
Message 20
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| Subject: | Re: ground plane |
--> AeroElectric-List message posted by: Kenneth Melvin <melvinke@direcway.com>
Great info. Thanks.
----- Original Message -----
From: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
Subject: Re: AeroElectric-List: ground plane
> --> AeroElectric-List message posted by: "Gilles.Thesee"
<Gilles.Thesee@ac-grenoble.fr>
>
>
> ----- Message d'origine -----
> De : "Kenneth Melvin" <melvinke@direcway.com>
> : <aeroelectric-list@matronics.com>
> Envoy : mercredi 24 septembre 2003 17:24
> Objet : AeroElectric-List: ground plane
>
>
> > --> AeroElectric-List message posted by: Kenneth Melvin
> <melvinke@direcway.com>
> >
> > When fitting a transponder antenna ground plane in a composite
airplane,
> does the shape of the metal plate matter? Is a rectangle as good as a
circle
> if the area is the same?
> > Kenneth Melvin
> >
>
> Kenneth,
> My understanding is as follows :
>
> -The radius of a circular plate must be 1/4 wave.
> - The DIAGONAL of a a square-rectangle must be 1/4 wave.
> - The ground plane may bend away from the antenna.
>
> Hope this helps,
> Gilles Thesee
>
>
Message 21
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| Subject: | Re: ground plane |
--> AeroElectric-List message posted by: Kenneth Melvin <melvinke@direcway.com>
Very helpful information. Thankyou!
----- Original Message -----
From: <richard@riley.net>
Subject: Re: AeroElectric-List: ground plane
> --> AeroElectric-List message posted by: richard@riley.net
>
> At 08:24 AM 9/24/03 -0700, you wrote:
> >--> AeroElectric-List message posted by: Kenneth Melvin
> ><melvinke@direcway.com>
> >
> > When fitting a transponder antenna ground plane in a composite
airplane,
> > does the shape of the metal plate matter? Is a rectangle as good as a
> > circle if the area is the same?
> >Kenneth Melvin
>
> From Jim Wier, on rec.aviation.homebuilt
> =============
>
> Think of an aluminum pie pan after you've eaten the
> pie. Circular, about 6" in diameter (I eat small pies). Anyway, you've
> got a disk of thin aluminum after you cut the bent-up edges of the pie pan
> off about 5.5 inches in diameter. Poke a 3/8" hole in the dead center of
> that aluminum disk, mount the little transponder antenna (the one with the
> little b-b on the top of the rod) and connector in the hole, point the rod
> DOWN towards the ground, and away you go.
>
> Some considerations:
>
> 1. It doesn't have to be circular. It can be square, elliptical,
> hexagonal, or an old stop sign. What IS important is that there MUST be
> equal metal on all sides of the radiating rod. What is ALSO important is
> that there must be some place on every edge that is 2.75" away from the
> center of the hole. Get it? If you do a SQUARE, make sure that you
> average the side length versus the hypotenuse so that somewhere along each
> edge there is a 2.75" length of metal from the center of the hole.
>
> 2. It doesn't have to be grounded to anything else in the airplane EXCEPT
> the shield of the coax running to the transponder. It CAN be grounded if
> you want, but it is not necessary.
>
> 3. It can be anything from one mil tinfoil to armor plate thick and it
> won't work any better or worse. Me? I use an old scrap of PC board for
> the plain and simple reason that I can SOLDER the connector to the copper
> foil and not have to ever worry about corrosion getting between the
> connector and the ground plane.
>
> 4. Put a piece of metal -- tinfoil to armor plate -- between the antenna
> and the "sensitive" parts of your anatomy. Think about putting your fanny
> in a microwave oven and the consequences thereof. Don't worry about your
> head. If we all had any brains we'd be out chasing women instead of
> messing with airplanes anyway.
>
> 5. In an airplane where it doesn't stick out into the slipstream and
> create drag, the little "b-b rod" antenna works every bit as well as the
> expensive blade. Save your money and get more avionics instead of wasting
> it on blade antennas. I know this little avionics company in Grass
> Valley...{;-)
>
> Jim
>
>
Message 22
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| Subject: | Instrument cutouts |
--> AeroElectric-List message posted by: "Alex Peterson" <alexpeterson@usjet.net>
>
> I'd like to proceed with the panel wiring & plumbing etc, and
> then slot in flight instruments at the last minute (i.e. in
> about a year's time) but I'm rather nervous about cutting
> holes and then discovering that the instruments I buy (esp.
> gyros) don't fit, e.g. if I've cut the holes too close together.
>
Why not wait until you have the instruments? If it is a year away,
you'll probably change your mind about numerous things. I don't see the
gain in doing the cutouts now.
Alex Peterson
Maple Grove, MN
RV6-A N66AP 372 hours
www.usfamily.net/web/alexpeterson
Message 23
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| Subject: | Connecting Whelen Strobes |
--> AeroElectric-List message posted by: "Larry Bowen" <Larry@bowenaero.com>
I'm installing the light/strobe in the rudder and am confused about this
drain wire.
I found the post below in the archives that asks many of the same
questions I have, but I didn't find a reply to questions 1-5. Anyone
know?
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
AeroElectric-List message previously posted by: "Robert L. Nuckolls,
III"
<bob.nuckolls@cox.net>
>Bob/Others - First - I bleieve you recommend attaching both ends of the
Whelen >strobe shielding on composites. What's the best way to attach
the AL
foil,
>solder wire to it? I've installed a Molex connector for service at the
>strake-wing junction, what kind of connector would you recommend there,
>another Molex? And finally, would it be sufficient to put a ring
terminal
>under the mounting screw for the ground connection at the light
fixture,
>or should I solder the sheild to the housing, or what?
There is a bare, stranded wired IN ADDITION to the three insulated
wires
under the shield. This forth wire is called a "drain wire" and its
purpose
is to provide you with a convenient means for making electrical
connection
to the shield-foil which is, as you've noted, impossible to make
connection with. You can extend the drain wire with a short piece of
wire, install a ring terminal and attach to mounting screw for
fixture.
If you DON'T do this, in all probability, you won't know the
difference.>>
6/29/2003
Hello Bob Nuckolls and Bret Ferrell, I'd like to flog this horse a few
more
lashes.
1) Bob Nuckolls really says the drain wire should be attached at both
ends on
a composite aircraft? But not on a metal aircraft? Why?
2) When one receives the strobe light installation kit from Whelen the
cable
already has two AMP plastic 3 wire connectors attached, one on each end.
These
connectors are the ones that plug into the mating 3 wire connectors at
the
strobe light ends. After cutting the cable somewhere in the middle and
snaking
those two cut ends through the airframe to the vicinity of the strobe
power
supply one installs the other two (different) appropriate 3 wire
connectors
provided by Whelen and plugs the cables into the power supply.
3) The installation instructions say that the drain wire should be
connected
to the housing / mounting of the power supply. Easy enough to do by
leaving
the drain wire longer when you cut the cable, strip it, and install the
3 wire
connectors that plug into the power supply.
4) But out at the strobe light end of the cable where the Whelen
installed
connectors are, Whelen has left no access to the drain wire. I suppose
one could
cut back the plastic covering, remove the aluminum shield, attach a
short
wire to the now exposed drain wire, and then attach that short wire to
some metal
part of the strobe light housing, but I find this action both puzzling
and
unnecessary.
5) Whelen has thousands of these units in service throughout the skies
mounted on both metal surfaces and composite wing tips. I am unaware of
any need
to
go through the additonal effort of connecting the drain wire to the
metal
light housing out at the strobe light end. Can anyone show me different?
'OC' Baker, Builder of KIS TR-1 #116 4/14/97 - ?/?/?
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