Wire type?

Discussion in 'Instruments / Avionics / Electrical System' started by SteveR, Jul 5, 2005.

1. Jul 5, 2005

SteveR

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I'm in the process of installing a radio, intercom, and battery. What wire types do people commonly use? MIL-W-22759/16? This is in an open cockpit aircraft, and wiring will be minimal, so I'm not concerned with toxic smoke/fumes (If my airplane is on fire, I've got more immediate problems...like the wings disappearing). I would just order some wire from Aircraft Spruce, but I have no idea what the sheath is like. I'd like something with a really tough, harder sheath, not the softer sheath that standard hook-up wire has.

Also, does anyone make or use wire with a braided sheath anymore? I think this would look better in my plane. I've seen some that seem to be a plastic sheath with a cloth braid. What is the general consensus on the durability & quality of this wire type, and is it even available today?

2. Jul 6, 2005

wally

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This is a topic I do know a little about from my previous day job. Gulfstream Aerospace, engineering, 16 years.

yes the MIL-W-22759/16 is the standard airframe wire. Aircraft Spruce sells it by the foot. I think it has a clear nylon outer layer and should do just fine anywhere in the airplane. Get a copy of FAA advisory circular AC43.13-1B, it shows how to install wiring among a lot of ohter usefull info. It is available free on-line at the FAA.gov website.

If you are concerned about it being rubbed against in your cockpit, you can put the wires in a bundle and then run the bundle through some plastic tubing. Or add some polyolefin shrink tubing over the wire or wires to help protect them.

Some of the older planes I have been around had the outer cover as a cloth braid. It was that way because the insulation material was not as durable as it is today.

I too am building an open cockpit plane (Pitts) and almost all the wiring will be in front of you behind the instrument panel so it should not be a worry.

And keep in mind, whatever you use, there will eventually be a time you have to show the plane to the FAA inspector or a DAR (designated airworthiness represenitive) in order to get your airworthiness. He will be much happier if he sees aircraft type materials and construction!
Best wishes,
Wally

Oh, I just checked your web pages. Nice plane and it is already flying! The only problem you might have is finding places to put the radios.

I am saving my pennies for a Micro-Air 760 comm and the T2000 transponder. They are about the only things I can fit in my little one place Pitts. I have a Val-Com 760 radio in my Cessna 150 and really like it but it is just too large to fit in the Pitts. Good luck!

Last edited: Jul 6, 2005
3. Jul 7, 2005

SteveR

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Thanks Wally, that tells me what I needed to know about the wire. One more question...do you (or most people) typically color-code the wires in your planes? The engineer in me wants to color code every wire, but aesthetically I think one color would be much better. I do have labels for each end of the wires.

For now I'm going to mount the antenna on the belly...the only place I have a suitable ground plane. I'd like the antenna to be completely hidden, so in the future, I'm going to try to mount a dipole antenna in the rear of the plane, since it is wood I think I can pull it off. I just need to find a location where I can mount it and maintain the proper spacing from the control wires, and do all of this through the inspection covers. Its kind of like trying to build a ship in a bottle.

I had every intention of using the 760 Comm radio when I bought this plane, but the A & P who did my pre-buy talked me into a handheld (for around $700 less than the 760). I have a VXA-150, so far it works fair with the rubber ducky antenna. Believe it or not, I have actually had a conversation at a 40SM range with a buddy in his Citabria. I think that was a fluke, I was probably benefiting somehow from the position of the handheld that day. My plane is based at a class D field UNDER DFW class B, and the tower's only complaint is wind noise. HOWEVER, using a handheld only a few inches away from my intercom causes an awful squeal when I transmit. That is why I am hurrying to install the belly antenna, and I'll do the internal antenna when I have more time to figure it out. I also initially had plans to use the T2000, but right now I'm not having any issues under the class B DFW shelf, and I don't want to pay$2,000 for the occasional trip through the class B.

Thanks again for the tips!

4. Jul 8, 2005

Craig

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Wire color

Steve -
I did my Duce wiring using only white (well, OK, the battery pos. is RED), and even with both ends of each wire coded, it is a major PAIN IN THE TAIL to sort them out when working out problems.

A trip to the local avionics shop revealed a rack full of 20 and 22 ga. colored wire - probably about 12 colors of each size, and also some colored shielded wire.

Do yourself a big favor, visit an avionics shop and get some wire from them - it makes tracing the circuits a breeze.

I am using hte MicroAir, and really love it. Also have a hand-held, but in the open-cockpit, it is hard to hear. Does have good range, however, and is great to leave with my buddy while I am test flying - we usually use 123.450 to talk back and forth while doing the time to climb, etc.

5. Jul 8, 2005

SteveR

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Good suggestion Craig, I will have to find an avionics shop. Its a pain to order all of this stuff online anyway.

Were you using a headset with your handheld? An adapter came with mine. I also bought some leather mic covers (\$12), and they make a massive difference in the useability of the intercom.

6. Jul 9, 2005

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