Today's Message Index:
----------------------
1. 06:26 AM - Pitot/antenna (Fergus Kyle)
2. 06:55 AM - Re: AeroElectric-List Digest: 6 Msgs - 12/25/06 (Lee Logan)
3. 07:32 AM - Re: Over Voltage (Dennis Haverlah)
4. 07:39 AM - Re: Re: AeroElectric-List Digest: 6 Msgs - 12/25/06 (John Erickson)
5. 08:50 AM - Re: Some experiments fail (Robert L. Nuckolls, III)
6. 08:59 AM - Re: Oops (Robert L. Nuckolls, III)
7. 09:12 AM - Oops too! ()
8. 09:23 AM - Re: Re: AeroElectric-List Digest: 6 Msgs - 12/25/06 (S. Ramirez)
9. 10:08 AM - OV protection in an internally regulated alternator (Grant Neilson)
10. 11:05 AM - Re: Back-Up Battery ground (Larry L. Tompkins, P.E.)
11. 11:19 AM - Re: Pitot/antenna (Bill Boyd)
12. 11:38 AM - Re: OV protection in an internally regulated alternator (Robert L. Nuckolls, III)
13. 11:47 AM - Re: Back-Up Battery ground (Ed Holyoke)
14. 11:53 AM - Re: Pitot/antenna (Robert L. Nuckolls, III)
15. 12:01 PM - Re: Back-Up Battery ground (Robert L. Nuckolls, III)
16. 12:25 PM - Re: Back-Up Battery ground (Carlos Trigo)
17. 12:27 PM - Re: Back-Up Battery ground (BobsV35B@aol.com)
18. 01:14 PM - Re: Oops! (Robert L. Nuckolls, III)
19. 01:19 PM - Re:OOOPS (EMAproducts@aol.com)
20. 01:25 PM - Re: Pitot/antenna (Bill Boyd)
21. 05:07 PM - Avionics Switch (Steve Glasgow)
22. 05:33 PM - Re: Avionics Switch (Alan K. Adamson)
23. 06:11 PM - Re: Back-Up Battery ground (Robert L. Nuckolls, III)
24. 06:12 PM - Re: Back-Up Battery ground (Robert L. Nuckolls, III)
25. 06:17 PM - Re: Pitot/antenna (Robert L. Nuckolls, III)
26. 06:36 PM - Re: Some experiments fail (Ernest Christley)
27. 07:08 PM - Z14 contactor(s) circuit question (rtitsworth)
28. 09:21 PM - Homemade Avionics/Electrical component bench tester (macrafic)
Message 1
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Bob N has obviously taken great pains to discuss the meritsa of combining
the two........ The thing that bothers me is that a 'hoizontal' antenna
loses 20dB to a vertical one and 26 inches does not give great scope to
adapt both. the one exception would be if the pitot could be mostly vertical
base isolated in cloth skin.
Cheers,
Ferg Kyle
Europa A064 914 Classic
Message 2
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Subject: | Re: AeroElectric-List Digest: 6 Msgs - 12/25/06 |
Those pictures of the B-1 gear up landing went around the "military circuit"
several months ago. My understanding is that the crew was fully aware the
gear were up and spent a long time trying to get it down. When all
emergency modes failed, they made an on-purpose gear up landing with
emergency crews standing by. The military stopped foaming the runway for
landings such as this quite a few years ago: Just makes the airplane slide
farther and it's better to have the firefighting foam still in the truck to
fight any fire that breaks out after landing than on the runway way behind
you. The captions I saw said the aircraft was not seriously damaged.
Not to say military crews never make mistakes, they do of course (lots of
them, but then they have a lot to do), but this is the kind of stuff where
they really earn their money. Anyone can fly the airplane when everything is
working right.
Regards,
Lee...
Message 3
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Subject: | Re: Over Voltage |
George,
I have the same regulator (VR 749) controlling a 100 amp Mazda
alternator. I'm running the engine on the ground while I finish the A/C
but I've experienced the same thing. High voltage at the battery.
Measured voltage is approximately 15.5 volts when running. I'm using an
Odyssey PC 680. Before I installed the Odyssey I was using a large 12
volt truck battery to start the engine and test the charging system.
Using the large battery and temporary wiring I did not have any over
voltage problems. As soon as I installed the PC 680 and flight ready
wiring the voltage at the battery went too high.
Dennis H.
Sally Kilishek wrote:
>
>I'm using a generic Ford regulator (Wells VR749) and a
>B&C OVM-14 overvoltage module wired as per Z-22 in my
>RV8.
>
>It worked fine for a short time, but after about 4
>hours of flying, the overvoltage indicator light
>started flickering. Bus voltage is rising above 15
>volts (one time as high as 16 volts), then dropping
>back below 15 volts and immediately rising again.
>
>It looks to me like the regulator isn't regulating and
>that the OV module is cutting off the field excitation
>until voltage drops below 15.
>
>I've replaced the regulator twice, but the problem
>continues.
>
>Is there somewhere else I should be looking?
>
>George
>N57GK
>
>__________________________________________________
>
>
>
>
Message 4
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Subject: | Re: AeroElectric-List Digest: 6 Msgs - 12/25/06 |
Not exactly. To read the accident report yourself, go to
http://usaf.aib.law.af.mil/B-1_8May06.pdf and enjoy...
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Lee Logan
Sent: Tuesday, December 26, 2006 7:54 AM
Subject: AeroElectric-List: Re: AeroElectric-List Digest: 6 Msgs - 12/25/06
Those pictures of the B-1 gear up landing went around the "military circuit"
several months ago. My understanding is that the crew was fully aware the
gear were up and spent a long time trying to get it down. When all
emergency modes failed, they made an on-purpose gear up landing with
emergency crews standing by. The military stopped foaming the runway for
landings such as this quite a few years ago: Just makes the airplane slide
farther and it's better to have the firefighting foam still in the truck to
fight any fire that breaks out after landing than on the runway way behind
you. The captions I saw said the aircraft was not seriously damaged.
Not to say military crews never make mistakes, they do of course (lots of
them, but then they have a lot to do), but this is the kind of stuff where
they really earn their money. Anyone can fly the airplane when everything is
working right.
Regards,
Lee...
Message 5
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Subject: | Re: Some experiments fail |
At 09:58 PM 12/25/2006 -0600, you wrote:
>
>By far I am not an antenna expert but what I've seen from the pictures
>there are several major issues.
>The length of the antenna element appears to be far shorter than it should
>be for a 118-136 MHz spectrum.
>The next thing I noticed is you go from coax to long simple single
>connector wires to connect to the element and the ground plane.
>You don't have much of a ground plane that I can see.
>Last, looks like you have the antenna element and the pitot in very close
>proximity to each other, if not at the proper spacing that has to impact
>your SWR, added together even more so.
>I use nothing more than a simple SS whip from Radio Shack bent into L
>shape and sized to produce a good SWR across normal frequency spectrum
>used in our area. I get out well and receive well.
>Bob didn't comment on these items that I noticed so either he's biting his
>fingers or what I noticed isn't a factor.
Didn't see the pictures until now Jerb but you're observations are spot
on.
Ernest. Your interest and willingness to explore antenna options
are commendable. The experiments are worthwhile learning tools.
But whether you're wanting to explore a new antenna configuration
or learn to make biscuits, the shortest path to success is to
study what has preceded your efforts.
Do some Google searches on antennas. There are thousands of
articles. Get copies of ANY editions of amateur radio antenna
handbooks. Those published by ARRL are noteworthy. Used book stores
on the 'net can provide a wealth of low cost, detailed data on how on
might approach the task of launching intelligence into the ether borne
on a stream of electromagnetic radiation. Your pictures
and words suggest that you've acquired some useful facts about
antennas but have yet to grasp the simple-ideas that support those
facts.
Get some books and study up on the relationship between operating
frequency and physical sizes of antennas. You'll need to have a rudimentary
grasp of transmission line theory and impedance at radio frequencies.
There's a chapter on antennas in the 'Connection that would provide
a beginning but what you're attempting to accomplish requires a study
into much more detail.
If you find something published for which you'd like more explanation
post a question about it here on the List. There are plenty of folks
here who would be willing to participate in some shared learning and
teaching experiences.
Now, if it's the 'short' answer you're looking for, I can tell you
that the current crop of pitot tubes offer little prospect for becoming
a useful antenna on an aircraft. But that doesn't mean we shouldn't
study and discuss why - both for your benefit and that of perhaps
1300 other folks who watch this list.
A quick note on other comments you offered:
>>I didn't think I could get much below an SWR of 2.5 or so, and was
>>willing to accept the resulting poor performance; but, 8.6 is really
>>high. But then I put the rubber ducky antennae from my handheld scanner
>>on the instrument. Everything in the aviation band was ">25", ie out of
>>the instruments range. It dropped into range at 130MHz and to 1.6 at 149.5.
>>
>>Considering that the handheld scanner seems to work, how viable would an
>>SWR of 10 to 20 work over here on the crowded eastern seaboard for mostly
>>day VFR operations?
Please understand that SWR has only a very loose connection
with antenna performance. SWR is a measure of the antenna system's
ability to accept power from the transmitter (or convey it to
a receiver). It says nothing about the antenna's ability to
efficiently radiate or intercept a signal.
A 50 ohm resistor has an SWR of 1:1 over the entire range of
interest but zero ability to function as an antenna. The MFJ-259
is of great value for improving power transfer by helping you
optimize a "match". But 1.5:1 SWR measured on a wet-string
does not insure that the wet-string will produce satisfactory
performance as an antenna.
Bob . . .
Message 6
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At 08:38 AM 12/26/2006 -0700, you wrote:
>Not exactly. To read the accident report yourself, go to
><http://usaf.aib.law.af.mil/B-1_8May06.pdf>http://usaf.aib.law.af.mil/B-1_8May06.pdf
>and enjoy...
>
>
Sit back in your chairs laddies and take another sip,
the fat lady is still singing!
Bob . . .
Message 7
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I can understand reasons for landing with gear up, becauseof forgetting to
check......................
But forgetting to check and landing with 1 wing????
http://www.whoisthemonkey.com/videos/31f15-flying-with-1-wing
Ron Parigoris
Message 8
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Subject: | Re: AeroElectric-List Digest: 6 Msgs - 12/25/06 |
John,
So what happens to guys (and gals) that have many years of service
experience combined with somewhat high ranking positions (Major, Lt. Col,
Col) that make such a drastic mistake? It doesn't reflect well on their
record, so my guess is that they will get RIFed out of the service, unless
they have superior political connections.
BTW, thanks for setting us straight on what really happened by using an
official document. This argument could have raged on forever.
Simon Ramirez, Aerocanard Builder
LEZ N-44LZ
Oviedo, FL 32765 USA
Copyright C 2006
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John
Erickson
Sent: Tuesday, December 26, 2006 10:38 AM
Subject: RE: AeroElectric-List: Re: AeroElectric-List Digest: 6 Msgs -
12/25/06
Not exactly. To read the accident report yourself, go to
http://usaf.aib.law.af.mil/B-1_8May06.pdf and enjoy...
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Lee Logan
Sent: Tuesday, December 26, 2006 7:54 AM
Subject: AeroElectric-List: Re: AeroElectric-List Digest: 6 Msgs - 12/25/06
Those pictures of the B-1 gear up landing went around the "military circuit"
several months ago. My understanding is that the crew was fully aware the
gear were up and spent a long time trying to get it down. When all
emergency modes failed, they made an on-purpose gear up landing with
emergency crews standing by. The military stopped foaming the runway for
landings such as this quite a few years ago: Just makes the airplane slide
farther and it's better to have the firefighting foam still in the truck to
fight any fire that breaks out after landing than on the runway way behind
you. The captions I saw said the aircraft was not seriously damaged.
Not to say military crews never make mistakes, they do of course (lots of
them, but then they have a lot to do), but this is the kind of stuff where
they really earn their money. Anyone can fly the airplane when everything is
working right.
Regards,
Lee...
Message 9
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Subject: | OV protection in an internally regulated alternator |
When using the aeroelectric connection diagram for crowbar overvoltage
protection for an internally regulated alternator, why is it necessary to
have the continuous duty contactor in the system? Doesn't the OV module
cause the alternator field circuit breaker to trip, effectively shutting
down the alternator? It seems a redundancy to me to have both the alternator
field circuit and the contactor. And when the circuit breaker trips and the
contactor opens is there any risk of a voltage spike or arcing from the
contactor?
Thanks for any responses. I know there must be something I'm not
getting..........
Grant Neilson
RV9A, Firewall forward
Message 10
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Subject: | Re: Back-Up Battery ground |
Why not just carry a small amount of ballast in the baggage compartment
that you can trade for cargo when the need arises? I think it's the
simplest solution and gives you the oppportunity to maximize cargo
capacity.
Larry
Message 11
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Subject: | Re: Pitot/antenna |
I wonder if we could prototype a helically-loaded "rubber duck" comm
antenna and slip a polypropylene tube inside it with an L-bend at the
end to act as a pitot; encase the whole thing in a streamlined radome.
Interesting excercise. Bandwidth would inevitably suffer from the
physical shortening versus a quarter wave. A lossy loading coil would
give some feeble de-ice heat during Tx (just kidding.) A lot of work
to shave a half knot of speed penalty, but a fun excercise
nonetheless. If I weren't busy with other projects, it's just the
kind of thing I'd try.
Come to think of it, a full size transponder antenna would easily fit
in a very modest blade pitot housing...
-Bill B
On 12/26/06, Fergus Kyle <VE3LVO@rac.ca> wrote:
>
> Bob N has obviously taken great pains to discuss the meritsa of combining
> the two........ The thing that bothers me is that a 'hoizontal' antenna
> loses 20dB to a vertical one and 26 inches does not give great scope to
> adapt both. the one exception would be if the pitot could be mostly vertical
> base isolated in cloth skin.
> Cheers,
> Ferg Kyle
> Europa A064 914 Classic
>
>
Message 12
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Subject: | Re: OV protection in an internally regulated alternator |
At 10:06 AM 12/26/2006 -0800, you wrote:
><grantneilson@telus.net>
>
>When using the aeroelectric connection diagram for crowbar overvoltage
>protection for an internally regulated alternator, why is it necessary to
>have the continuous duty contactor in the system? Doesn't the OV module
>cause the alternator field circuit breaker to trip, effectively shutting
>down the alternator? It seems a redundancy to me to have both the alternator
>field circuit and the contactor. And when the circuit breaker trips and the
>contactor opens is there any risk of a voltage spike or arcing from the
>contactor?
>Thanks for any responses. I know there must be something I'm not
>getting..........
See:
http://www.aeroelectric.com/FAQ/Internal_Regulator/
Links to z-figures don't work but you can get the latest
z-figures at:
http://aeroelectric.com/articles/Rev11/AppZ_R11J.pdf
For a lengthy analysis of this an related/unrelated
issues surrounding the use of stock automotive alternators
in aircraft goto:
http://www.matronics.com/searching/ws_script.cgi
and search the AeroElectric List archives for
"b-lead disconnect"
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 13
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Subject: | Back-Up Battery ground |
Toolkit for instance. Survival supplies good too.
Pax,
Ed
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Larry
L. Tompkins, P.E.
Sent: Tuesday, December 26, 2006 11:04 AM
Subject: Re: AeroElectric-List: Back-Up Battery ground
Why not just carry a small amount of ballast in the baggage compartment
that you can trade for cargo when the need arises? I think it's the
simplest solution and gives you the oppportunity to maximize cargo
capacity.
Larry
Message 14
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Subject: | Re: Pitot/antenna |
At 02:18 PM 12/26/2006 -0500, you wrote:
>
>I wonder if we could prototype a helically-loaded "rubber duck" comm
>antenna and slip a polypropylene tube inside it with an L-bend at the
>end to act as a pitot; encase the whole thing in a streamlined radome.
>Interesting excercise. Bandwidth would inevitably suffer from the
>physical shortening versus a quarter wave. A lossy loading coil would
>give some feeble de-ice heat during Tx (just kidding.) A lot of work
>to shave a half knot of speed penalty, but a fun excercise
>nonetheless. If I weren't busy with other projects, it's just the
>kind of thing I'd try.
>
>Come to think of it, a full size transponder antenna would easily fit
>in a very modest blade pitot housing...
Cool! Hadn't considered that.
Hmmm . . . maybe better yet, slice metal pitot tube into
horizontal and vertical portions (right across
the knee joint). Materials that traverse the joint wound
have to be non-conductor -OR- fabricated in a way
that provides loading components for the comm antenna.
Now the horizontal portion becomes more of a minimally
radiating top-hat and the vertical mast enjoys majority
current flow in the right polarity.
THAT could work! Except for the inevitable distortion
in pattern that arises from a leading edge location
on wing, it might function rather well.
If I can get an IR&D activity spun up next year, I'll toss
that out on the table to see if some RF-inquisitive guys
might like to go mock that up in the lab. It would be an
easily crafted experiment.
Bob . . .
Message 15
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Subject: | Re: Back-Up Battery ground |
At 11:04 AM 12/26/2006 -0800, you wrote:
>Why not just carry a small amount of ballast in the baggage compartment
>that you can trade for cargo when the need arises? I think it's the
>simplest solution and gives you the oppportunity to maximize cargo capacity.
>
>Larry
An astute question sir. A Bonanza I used to rent had 6 plastic jugs
in the baggage compartment with a tiedown net. If one anticipated
lightly loaded flights, the jugs are filled with water to keep
the balance in range. If one were going to use the baggage compartment
both ways, then the net was used to wrap up jugs and hang them on
the hangar wall before departure. If you needed the weight only
one way, the jugs could be filled/emptied as needed for up to 50
pounds of aft ballast adjustment.
If I wanted to have adjustable balance while minimizing weight,
how about a plastic tank as far aft as possible with external
filler/drain access. Fill or empty as needed. Obviously, changes
could be accomplished only at temperatures above 32 degrees!
Sailplanes use water as a dynamic ballasting medium, don't
see why Haulplanes couldn't do it too.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 16
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Subject: | Re: Back-Up Battery ground |
Bob, Larry et all
Please forget the reason why I may want to put the Avionics Back-Up battery
in the tail, and please answer the electric questions:
- Can I connect the (-) terminal of that battery to the tail's ground lug,
which is isolated from the fuselage and is directly connected to the (-)
terminal of the "Main" battery ?
- Can I continue to use that same ground lug to connect the other grounds
( from the tail light, the strobe beacon, and the elevator trim motor)
there?
- Isn't there any possibility of "ground loop"?
Carlos
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
Sent: Tuesday, December 26, 2006 7:59 PM
Subject: Re: AeroElectric-List: Back-Up Battery ground
> <nuckollsr@cox.net>
>
> At 11:04 AM 12/26/2006 -0800, you wrote:
>
>>Why not just carry a small amount of ballast in the baggage compartment
>>that you can trade for cargo when the need arises? I think it's the
>>simplest solution and gives you the oppportunity to maximize cargo
>>capacity.
>>
>>Larry
>
> An astute question sir. A Bonanza I used to rent had 6 plastic jugs
> in the baggage compartment with a tiedown net. If one anticipated
> lightly loaded flights, the jugs are filled with water to keep
> the balance in range. If one were going to use the baggage compartment
> both ways, then the net was used to wrap up jugs and hang them on
> the hangar wall before departure. If you needed the weight only
> one way, the jugs could be filled/emptied as needed for up to 50
> pounds of aft ballast adjustment.
>
> If I wanted to have adjustable balance while minimizing weight,
> how about a plastic tank as far aft as possible with external
> filler/drain access. Fill or empty as needed. Obviously, changes
> could be accomplished only at temperatures above 32 degrees!
>
> Sailplanes use water as a dynamic ballasting medium, don't
> see why Haulplanes couldn't do it too.
>
> Bob . . .
>
Message 17
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Subject: | Re: Back-Up Battery ground |
In a message dated 12/26/2006 2:03:20 P.M. Central Standard Time,
nuckollsr@cox.net writes:
An astute question sir. A Bonanza I used to rent had 6 plastic jugs
in the baggage compartment with a tie down net. If one anticipated
lightly loaded flights, the jugs are filled with water to keep
the balance in range. If one were going to use the baggage compartment
both ways, then the net was used to wrap up jugs and hang them on
the hangar wall before departure. If you needed the weight only
one way, the jugs could be filled/emptied as needed for up to 50
pounds of aft ballast adjustment.
If I wanted to have adjustable balance while minimizing weight,
how about a plastic tank as far aft as possible with external
filler/drain access. Fill or empty as needed. Obviously, changes
could be accomplished only at temperatures above 32 degrees!
Sailplanes use water as a dynamic ballasting medium, don't
see why Haulplanes couldn't do it too.
Bob . . .
Good Afternoon Bob,
Just for a statistical data point, in the days of the DC-3, all airlines
used canvas bags with lead shot as ballast. They had canvas handles and each
weighed fifty pounds.
A baggage a cart full of ballast bags was maintained at each station. The
bags would be thrown in the aft baggage compartment of the DC-3 so as to
maintain a reasonable CG. If any one station got a little low on bags or a little
heavy on bags, a message would be sent and bags would be moved from the
'Heavy' stations to the 'Light' stations.
If I Recall Correctly, for an empty airplane, we needed around five hundred
pounds of ballast in the aft compartment. I could be off by a couple of
hundred pounds on that though.
Worked well for a stable airline.
The idea of hauling ballast has a long history with sailing ships. They
would unload paying cargo in the New World and load up on rocks and stones to
get
reasonable stability for the trip home. A major effort was made to load up
stones that may have some value when the ship reached a port that had better
paying cargo available.
Nothing much new under the sun is there?
Do Not Archive
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
Message 18
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At 09:53 AM 12/26/2006 -0500, you wrote:
>Those pictures of the B-1 gear up landing went around the "military
>circuit" several months ago. My understanding is that the crew was fully
>aware the gear were up and spent a long time trying to get it down. When
>all emergency modes failed, they made an on-purpose gear up landing with
>emergency crews standing by. The military stopped foaming the runway for
>landings such as this quite a few years ago: Just makes the airplane slide
>farther and it's better to have the firefighting foam still in the truck
>to fight any fire that breaks out after landing than on the runway way
>behind you.
Interesting. At Cessna, we didn't foam the runway, we wet the grass.
There was a large field east of the Pawnee plant that was planted in
grass. The one gear up landing I got to watch was during our O-2A
development
days when the test pilot had to recover an aircraft that would not
extend the gear. They sprayed the grass down. I don't think they went
back to refill the trucks . . . nobody expected any fire.
The C337 had keel structure designed to tolerate such abuse.
As I recall, the airplane was flying the next day with a couple
of new belly skins and two new antennas.
>The captions I saw said the aircraft was not seriously damaged.
>
>Not to say military crews never make mistakes, they do of course (lots of
>them, but then they have a lot to do), but this is the kind of stuff where
>they really earn their money. Anyone can fly the airplane when everything
>is working right.
Lee, thank you for helping out with "the rest of the story".
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 19
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Gentlemen,
There are those who are going to and those who have, sorta like flying tail
draggers and ground looping. The laws of averages they say will eventually
catch up with everybody. I've been lucky in my 25,000+ hours, over a couple
thousand in tail draggers, but it has been close a few times, ground loops and
a couple times with the gear! Following and using a checklist properly will
help eliminate the gear up problem, but mechanical things do happen. It is
easy to after the fact comment with out all details. Accidents usually have
three main causes.
For this reason our AOA system has an optional gear warning, It does not
depend upon just throttle being reduced, but on three things, manifold pressure,
gear position, and AOA. Audio voice says Landing Gear, Landing Gear. On
amphibian aircraft it is wired so that when above conditions are met one will
always get the Landing Gear, Landing Gear Audio to verify down for landing on
terra firma or splashing down on H2O. Two companies who sell amphibian floats
and amphibian aircraft highly recommend the system. _www.riteangle.com_
(http://www.riteangle.com)
Elbie
Elbie Mendenhall
President
EM Aviation, LLC
13411 NE Prairie Rd
Brush Prairie, WA 98606
360-260-0772
_http://www.riteangle.com_ (http://www.riteangle.com/)
Message 20
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Subject: | Re: Pitot/antenna |
No reason I see why we can't have the pitot shaped like an inverted-T
rather than an L. That would allow more top (bottom) loading to be
added, and the "hat" would not radiate, thus negating any directivity
effects that would arise from the L-shape. The back of the T would be
strictly antenna-related and not needed for Pitot, of course.
I like it.
-Bill B
On 12/26/06, Robert L. Nuckolls, III <nuckollsr@cox.net> wrote:
>
> At 02:18 PM 12/26/2006 -0500, you wrote:
>
> >
> >I wonder if we could prototype a helically-loaded "rubber duck" comm
> >antenna and slip a polypropylene tube inside it with an L-bend at the
> >end to act as a pitot; encase the whole thing in a streamlined radome.
> >Interesting excercise. Bandwidth would inevitably suffer from the
> >physical shortening versus a quarter wave. A lossy loading coil would
> >give some feeble de-ice heat during Tx (just kidding.) A lot of work
> >to shave a half knot of speed penalty, but a fun excercise
> >nonetheless. If I weren't busy with other projects, it's just the
> >kind of thing I'd try.
> >
> >Come to think of it, a full size transponder antenna would easily fit
> >in a very modest blade pitot housing...
>
> Cool! Hadn't considered that.
>
> Hmmm . . . maybe better yet, slice metal pitot tube into
> horizontal and vertical portions (right across
> the knee joint). Materials that traverse the joint wound
> have to be non-conductor -OR- fabricated in a way
> that provides loading components for the comm antenna.
>
> Now the horizontal portion becomes more of a minimally
> radiating top-hat and the vertical mast enjoys majority
> current flow in the right polarity.
>
> THAT could work! Except for the inevitable distortion
> in pattern that arises from a leading edge location
> on wing, it might function rather well.
>
> If I can get an IR&D activity spun up next year, I'll toss
> that out on the table to see if some RF-inquisitive guys
> might like to go mock that up in the lab. It would be an
> easily crafted experiment.
>
> Bob . . .
>
>
Message 21
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Does anyone have any information on building a Avionics Switch System?
I'm helping a friend with an All Electric Airplane with 20-Amp E-Bus and he
wants a Avionics Switch.
Could I somehow wire a Switch between two FH-10 Fuseholders? One for all
the avionics and one for all the other Main Bus stuff.
Any input would be appreciated.
Steve Glasgow-Cappy
N123SG RV-8
Cappy's Toy
Message 22
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Steve, my only experience with an Avionics Master is with my electronics
modules for my Lancair. They use a contactor to switch the avionics buss
off the primary buss. And an associated fuseable link for the right
amperage.
Alan
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Steve
Glasgow
Sent: Tuesday, December 26, 2006 8:05 PM
Subject: AeroElectric-List: Avionics Switch
--> <willfly@carolina.rr.com>
Does anyone have any information on building a Avionics Switch System?
I'm helping a friend with an All Electric Airplane with 20-Amp E-Bus and he
wants a Avionics Switch.
Could I somehow wire a Switch between two FH-10 Fuseholders? One for all
the avionics and one for all the other Main Bus stuff.
Any input would be appreciated.
Steve Glasgow-Cappy
N123SG RV-8
Cappy's Toy
Message 23
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Subject: | Re: Back-Up Battery ground |
At 08:24 PM 12/26/2006 +0000, you wrote:
><trigo@mail.telepac.pt>
>
>Bob, Larry et all
>
>Please forget the reason why I may want to put the Avionics Back-Up
>battery in the tail, and please answer the electric questions:
> - Can I connect the (-) terminal of that battery to the tail's ground lug,
>which is isolated from the fuselage and is directly connected to the (-)
>terminal of the "Main" battery ?
Can't imagine what you're describing here. Ground the
battery to local structure.
> - Can I continue to use that same ground lug to connect the other grounds
>( from the tail light, the strobe beacon, and the elevator trim motor)
>there?
Ground these devices to local structure. You don't
need a "tail ground" in a metal airplane for items
located in the tail.
> - Isn't there any possibility of "ground loop"?
No.
Do you plan a "mini battery contactor" for this "mini-battery"?
Even thought it's a relatively small battery compared to
the ship's battery, it is capable of significant fault currents
and should be treated like any other battery with respect to
positive disconnection via local contactor.
It would be helpful if you could publish sketches of your
proposed wiring.
Bob . . .
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Subject: | Re: Back-Up Battery ground |
>Good Afternoon Bob,
>
>Just for a statistical data point, in the days of the DC-3, all airlines
>used canvas bags with lead shot as ballast. They had canvas handles and
>each weighed fifty pounds.
>
>A baggage a cart full of ballast bags was maintained at each station. The
>bags would be thrown in the aft baggage compartment of the DC-3 so as to
>maintain a reasonable CG. If any one station got a little low on bags or a
>little heavy on bags, a message would be sent and bags would be moved from
>the 'Heavy' stations to the 'Light' stations.
>
>If I Recall Correctly, for an empty airplane, we needed around five
>hundred pounds of ballast in the aft compartment. I could be off by a
>couple of hundred pounds on that though.
>
>Worked well for a stable airline.
>
>The idea of hauling ballast has a long history with sailing ships. They
>would unload paying cargo in the New World and load up on rocks and stones
>to get reasonable stability for the trip home. A major effort was made to
>load up stones that may have some value when the ship reached a port that
>had better paying cargo available.
Puts a whole new twist on the term "dead heading" . . . nothing
deader than a rock!
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
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Subject: | Re: Pitot/antenna |
At 04:25 PM 12/26/2006 -0500, you wrote:
>
>No reason I see why we can't have the pitot shaped like an inverted-T
>rather than an L. That would allow more top (bottom) loading to be
>added, and the "hat" would not radiate, thus negating any directivity
>effects that would arise from the L-shape. The back of the T would be
>strictly antenna-related and not needed for Pitot, of course.
>
>I like it.
I've added it to my notebook of "cookies" to toss on the
table should I find an opportunity to suggest it in the
future.
Bob . . .
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Subject: | Re: Some experiments fail |
Robert L. Nuckolls, III wrote:
> Ernest. Your interest and willingness to explore antenna options
> are commendable. The experiments are worthwhile learning tools.
> But whether you're wanting to explore a new antenna configuration
> or learn to make biscuits, the shortest path to success is to
> study what has preceded your efforts.
>
> Do some Google searches on antennas. There are thousands of
> articles. Get copies of ANY editions of amateur radio antenna
> handbooks. Those published by ARRL are noteworthy. Used book stores
> on the 'net can provide a wealth of low cost, detailed data on how on
> might approach the task of launching intelligence into the ether borne
> on a stream of electromagnetic radiation. Your pictures
> and words suggest that you've acquired some useful facts about
> antennas but have yet to grasp the simple-ideas that support those
> facts.
Thank you, Bob, but I've believe I've bitten off way more than I can
chew. The problem with antennaes is what I've heard from both you and
Jim Weir. To paraphrase: A wet noodle in a cast iron swimming pool
will radiate, and it gets better from there. The implication is that
just about anything will work, for some qualified definition of 'work'.
This experiment was an exercise in placing a chunk of existing metal at
it's appropriate spot somewhere is the spectra of wet noodle to
'dedicated ham special'.
I don't have the resources, time or energy to remanufacture the tube,
and once I get past the basics of antennae theory I started to get
swimmy headed. The pitot tube has to remain unmodified so that it may
serve its intended purpose for one very profound reason. I've done paid
for it and it was EXPENSIVE 8*) I also think I know more about antennae
than I originally set out learn...which is a good thing, but for the
swimmy headiness. At this point, I know the radio will transmit well
enough to be recieved in the kitchen from the garage (put that unit in
your metric pipe and smoke it 8*), and I can only presume that it was
received clearly since it brought the family out to ask what I wanted
(another great measurment unit for the international community 8*).
The next step will be to see how well it does at the airport during the
taxi test. It shouldn't be very hard to pre-arrange for a few strategic
radio checks. If it is sufficient, it will get qualified in the
pattern. If it proves worthwhile, I'll extend the range until I know
how effective it is. If it is really bad, I'll try something a little
more conventional, though not as universally applicable. I could fish a
welding rod down into the foam core of my air intake, for instance.
All in all, I think this has been a worthwhile experiment for me, and
I'm especially pleased that my little splash has stirred the neurons of
a few that have many more to stir than I. Marc Beranger inspired me. I
inspire someone else. They develop something that exceeds, even by the
slightest of measures, what what done before. I LOVE this internets thing.
Message 27
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Subject: | Z14 contactor(s) circuit question |
Bob, etal,
I noticed on the Z-14 schematic there is not a breaker, nor fuse, nor
fuseable link, anywhere along the current path from the battery(s) to the
battery contactor master switch(es) on the panel (and then to ground).
A short (wire failed to ground) between the contactor and the switch would
just keep the contactor closed (the same as the switch being on) and thus no
risk of additional damage, fire, etc. (due to the resistance of the
contactor coil).
However, if the contactor itself failed internally and shorted the power
terminal to the switch/coil terminal, it seems the 22AWG switch wire would
fry.
Perhaps the likelihood of that is so remote as to outweigh the complexity/
risk of an additional component in the circuit. However, breakers and fuses
are pretty reliable and with Z14 there is Bus#2 and the cross tie, which
could be used if the #1 master breaker/fuse failed and caused the #1
contactor to open (and/or vise versa).
Thus, I am thinking of perhaps putting a fuse(s) in-line with the master
switch(es). Thoughts?
Rick
Message 28
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Subject: | Homemade Avionics/Electrical component bench tester |
Anybody have a lead on plans/instructions for a simple homemade avionics bench
tester? One that would include a 12V battery, batter charger, and a box with
a couple of switches and 3-4 different amp circuits protected by fuses? The idea
would be to drive the various electonic components simply by hooking them
into the correct circuit, based on its current draw; thinks like lights, flashers,
servos, etc..
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=83707#83707
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