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radio interference, flying wires, wing rigging.

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radio interference, flying wires, wing rigging.

Old 03-23-2003, 06:41 PM
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Eindecker_pilot
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Default radio interference, flying wires, wing rigging.

I need to install flying wires on a WWI airplane wing. I've got Proctor flying wire (bare metal) and nylon coated wire from Du-bro. Haven't decided which one to actually install yet.

I am concerned about radio interference from all of this wire, as either one (bare metal wire or coated wire) will effect the radio signal to some unknown extent.

What about kevlar wire? That should eliminate any risk of interference from the metal wires, right?

If kevlar wire is not an option, what is the safest way to install these metal flying wires?

thanks,
Greg
Old 03-23-2003, 11:15 PM
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Denjones
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Default Flying wires

I used the Sullivan flying wires on my deceased Fun-Tiger and didn't have any problems with interferrence. I did use the kevlar though.
Old 03-24-2003, 01:19 AM
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Bish Wheeler
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Default radio interference, flying wires, wing rigging.

The thing you MUST NOT do with metal flying wires is to allow a "loop" to be established. For example: A wire, starting above the wing at the fusalage, going out to a point on the wing, then through the wing, back through the gear, etc, etc all the way around and back up to the fusalage and connecting to the wire you started out with. That would be a loop and it will cause you no end of problems. If you need your plane to be so rigged, use nylon or some other non conducting material to "Break" the loop some where.

Bish
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Old 03-24-2003, 01:30 AM
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Eindecker_pilot
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Default flying wires & interference

Thanks, Bish. My set-up is such that I won't have a loop as you describe. I will however have wires on the top of the wing, and wires on the bottom of the wing. However, the top and bottom sets will not be directly connected to each other.

The wing-end of each wire is connected to a cable anchor that is fastened with a wood screw to gussets in the wing structure. In other words, the wood of the wing separates the top and bottom wire sets.

The lengths of the wires vary, but the longest will be about 30 inches from the kingpost out to the wing tip. There are sixteen wires in total (including top and bottom) and that just seems like a lot of metal in between my transmitter on the ground and the reciever antennae!

I should just bite the bullet and buy some kevlar cable. I wish I had been this paranoid before I bought the metal wire, though! Oh well, live and learn.

Any watch-outs in regards to kevlar? Whatever I end up with, I do want the rigging to be structurally functional.

thanks,
Greg
Old 03-24-2003, 01:34 AM
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Bish Wheeler
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Default radio interference, flying wires, wing rigging.

Well as I said, you won't have trouble with wire if you "break" it. Have never used Kevlar, so can't comment, but wire is easy to use and to solder. I'm sure either will be fine.

Bish
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Old 03-24-2003, 03:20 AM
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Default radio interference, flying wires, wing rigging.

A club member brought his 1/3 scale sopwith pup out to the field today. This thing is huge and is full of rigging cables. The cables are bare metal and there are about 8 of them on the wings. He is also using metal pull/pull on the rudder and elevator. Thats a lot of metal wire and he has zero probs with interferance.

Warren
Old 03-24-2003, 03:26 AM
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Default radio interference, flying wires, wing rigging.

Thanks for the advice everyone. I guess I feel more comfortable with the metal flying wires. It is easy to get paranoid and over-analyze things after I spent a year building this airplane!

-Greg
Old 03-26-2003, 09:18 PM
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Default radio interference, flying wires, wing rigging.

I'm not sure what model your building but my Jenny has a lot of wire, structural flying wires, scale pull-pull controls etc. I also worried about interference and did range checks on the ground with the engine running. No problem.

I must keep power on for landing as all that wire has a lot of drag.
Old 03-29-2003, 08:11 PM
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MAJSteve
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Default radio interference, flying wires, wing rigging.

I rigged tail wires with a big loop through metal crimping sleeves in the balsa - don't. One came out and drove me nuts trying to guess what was causing the interference during run-up. It was vibrating on the wire at specific frequencies.
Old 03-29-2003, 10:30 PM
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Hurri
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Default radio interference, flying wires, wing rigging.

I have some 4 WW1 bipes , some have total of 6 pull wires , [4 elev; 2 rudd;] I use plastic coated fishing wire , 60, 80 lb test . If the wires rub on each other it is not metal on metal so no interferance . Sleeves on the ends are crimped , Also put the antenna on the very bottom of the fuse , in a plastic tube , that way as you look up from the tx when flying , the antenn; is below the control wires . There are control wires for elev; rudd; & also loads of flying wires , never even a glitch in 15 years of big bipes .
Old 04-01-2003, 07:08 AM
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Default radio interference, flying wires, wing rigging.

I 've always used 90 lb. fishing line with a 2-56 tie rod end screwed onto it and glued with CA. They have lasted over eighteen years on my eight foot wing bi plane.

give it a try it works! and never any radio interference.
Old 08-13-2003, 03:59 PM
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Default radio interference, flying wires, wing rigging.

Flying wires necessary only if you're a loop de loop guy. I'm a boring flyer-just in a circle above the field. Many folks say, "Why don't you try a loop or a roll?" And I say, "Uh huh." One pain in the neck always say, "You're flying your cub too fast." And I say, "Goodbye Dave."

Kraus
Old 08-13-2003, 04:50 PM
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Default radio interference, flying wires, wing rigging.

I've heard the "loop" thing through the years but have never really seen any interference as a result.

The most often encountered problem with flying wires are metal to metal interference between clevis, or wire, abrading against the surface of the mounting bracket.

The last instance of this I observed on my friends extra 300. He had used the plastic jacketed wire, similar to that used for pull/pull installations, and he looped it through metal brackets attached to rudder and stab.

The wires would abrade and wear through the plastic jacket and come into contact with the metal bracket. Wala, electrical interference.

Metal to metal interference is caused by a phenomena termed "thermal EMF".

Thermoelectric EMFs are small voltages developed at the junctions of dissimilar metals. The magnitude of the voltage depends both on the type of metals used as well as the temperature differences between junctions.

The high frequency vibration levels of our gassers can cause quite a thermal rise in two surfaces that are abrading. An analogy would be similar to rubbing two sticks together to make fire, rubbing two metals together will make voltage/electrical noise.

Accompanying the temperature rise are ac voltages that are radiated from the junction(s) and picked up as electrical noise by our receivers.

This noise, because of the close proximity to our antennas, will cause the receiver to "believe" that it's receiving a very strong signal and subsequently causes the receiver to close down it's rf amplifier in response.

Thermoelectric EMFs can be eliminated by using no metal to metal connections.

Now some guys will claim that they have made similar hookups before and have had no problem(s). Others use pCM receivers and don't know they have a problem (until too late).......

This is a measure of "good practice" to avoid these kinds of problems. Just because you got away with it a couple of times doesn't mean that, given just the right set of circumstances that you won't encounter it on the next airplane.

So the motto is "never use metal/metal" in a gasser if at all possible.

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