Can anyone tell me the purpose of twisting the servos wires. Ive seen pics of setups and all the wires were twisted pretty tightly. Im buidling a new plane with all new radio gear and wondering what the benefits were if any.

It helps eliminate RF noise from interfering with your receiver. The longer the servo leads/extensions the more this simple technique will help.

I don't twist my wires but I do coil them to shorten them as much as possible. The usual tangle of wires that looks like a mares nest is easily placed and traceable beside the neat appearance of the interior.

Sir, if you are coiling up your long leads, you are creating a RF coil that can start radiating energy itself. Wad the extra wire in a random pattern to offset the effects of creating an RF coil, and wire tie it together. May not look as nice, but it will cause far less troubles.
(Background in electronic engineering)

Twisting the leads will only help if you are in a magnetic field created by AC, won't do a thing for you in so far as your RC interferance. The purpose of the twist is to have the induced field coupled in out of phase in each half of the turn of the twist thus canceling out the induced current. It does make a neater installation though so doesn't hurt anything to twist them.

I understand that to twist servo wires addresses an issue with gas ignition engines.
Let me quote Airwild Hobbies for you:
"It is a known fact that ignition generated electro-magnetic noises (EMI) is an unfortunate by-product of our high-performance power plant. By twisting leads together the propagated electro-magnetic field in each lead cross-couples to its neighboring fields and dampens the potentially adverse interferences."
Airwild hobbies are experts in my opinion. They are even supporting pros.
http://www.airwildhobbies.com/MoreIn...&level=2&id=38

What's more, new servos are being built with twisted leads. I just purchased some new Hitec servos with twisted leads. I'm sure this is more that a fad to clean up your install.
Also, in a new article in March "Model Airplane News" on page 140 for building your own servo extensions, the author writes about twisting the wires. However he doesn't tell why.
I am working on my first gasser, and I have some servo jitters in my system. I am currently working on twisting som home made long leads to clean this up.

I think it's kinda funny..

All my 20 year old G plug Futaba servos have twisted leads.. then they went flat with the J type.. now Twisted is cool again..

I am seeing the same thing. I have alof of futaba G on board equipment, and it is all twisted. Then I have my new JR radio equipment and its flat as a piece of plywood. However I do twist them on my larger airplanes and it helps alot!

Arrgh... I can't stand all this well intentioned but inaccurate information. Here's one more opinion. Add it to the above posts and choose the one you like.

Twisting the wires is effective only in the following two cases:

1) The three wires are separate - not part of a flat cable bonded together by each wires insulation. Twisting the wires holds them in close proximity, thereby making the cable less susceptible to EMI/RFI.

2) The servo cable, whether flat or separate wires, runs in close proximity to (e.g. touching) other cables or metal objects. In this case the twisting helps equalize coupling among the conductors.

Twisting a flat cable (most servos cables are flat) that is not in proximity to other cables or metal objects (usually the case in RC airplanes) accomplishes nothing.

One more thing, coiling the servo lead has the same effect as placing a ferrite torroid on the servo cable... it chokes off common-mode RF currents. This is sometimes a good thing but not always. You might try this if you experience RFI/EMI problems, for example from a gas engine ignition.

This is what Futaba has to say
http://www.futaba-rc.com/faq/product-faq.html#q136
Tony Hallo

tony........futaba is talking about electo-magnetic fields produced by the current flowing in the wires themselves... since the current flowing in red and black leads is opposte to each other ,then the magnetic fields are also opposite and therefore cancell each other. thats their theory.......... when a external electro-magnetic field passes across twisted pairs it induces equal currents in each wire. if the first amplifier in the device (that the wires go to) has some form of common mode rejection, the interference is rejected. this is EE 401

Well, out of the pan and into the fire!
The original intent of twisted wires was to HELP reject induced interference. For the most part everybody is saying the same thing but with different terms.

A length of wire that is coiled up but does not allow the strand to cross itself ( such as 90 degrees) does make a RF coil and will attract interference from an outside source. Go back in time to the old AM and FM radio days before solid state RF filters and you'll find choke coils were quite common. But to make a choke coil the wire was wraped in a coil and then one end was routed through the center of the coil so that it "cut" across the field of the coil. This is the same reason all RC radio makers tell you "never wrap the antenna lead or tie a knot in it" This will change the frequency "tuning" length of the antenna at the point of the knot or anywhere the wire crosses itself. Another reason to twist long servo leads is to prevent the length from being the same as or a multiple of the antenna lead. In the old crystle radio we made as kid do you remember a battery being used? The antenna set the frequency and induced the EMF need to operate the radio. If you wanted better reception or more volume all you had to do is run another equal lenght of wire in parallel with the antenna. The result was more reception and induction area. If your antenna length is say 36" a run of wire that is 36, 27, 18 or 9 inches could pick up other signals in the same frequency band. The + or - servo lead usually won't present a problem in this example because the interference is actually absorbed by the battery. But (I know a lot of electronic gurus are going to scream here) BUT the interference can be induced on the servo signal line and disrupt the PWM signal to the servo or feed back to the receiver. Futaba uses isolation circuits in both the receiver and the servo so they no longer twist the leads. Notice in the thread that quotes them, they only say twisting is not needed in THEIR products. Not only do I twist the leads in my planes but any time there is a long lead run I tie an overhand knot at random points to ack as a crude choke. So I'm crazy!

One statement above said in effect, that magnetic fields are only created by AC circuits. PWM signals are DC in nature but do create a magnetic field. As a matter of fact any time a current flows in a conductor a magnetic field is created. When the flow stops or changes direction, then the field collaspes and BEMF occurs. If magnetic fields were only created by AC then DC electric motors would not work. After working on autos for 35 years and getting a degree in Electronics and having a FCC Operator Lic. with RADAR Endorcement I can say that twisted servo leads do help to prevent interference. It's the same reason CAT 5 network leads use twisted pairs.

I noticed JR servo wires are also flat....

I twist my wires cause it looks cool