Bryan,

I feel your pain. I just had an almost identical situation to yours. My servos would go nuts at only about 20 to 25 feet away. In my case, the plane is a BVM Ultraviper, BVM fan, engine, and pipe and the radio is a Futaba 8UAFS.

I tried everything and the problem defied solution. I tried three different brand new receivers, all the same make, model and channel and which were proven to have excellent range in other planes. Even tried a JR 10 channel PCM receiver on another channel. It got only about 10 feet away before the servos went crazy. I tried a different battery pack, isolated the switch, unplugged each servo one at a time, plugged them back in one at a time. Nothing worked. Next, I thought I had some excess length in some of the servo leads so I ordered new leads custom made to the exact length I needed. Still no help.

I failed to mention earlier that my servos are all Futaba high end servos and all of the servo extensions and Y harnesses are buffered and from Electro-Dynamics. The two aileron servos are digitals.

I have never discovered the source of the problem! But, I did discover a workaround solution and it is the only thing that worked. A friend of mine suggested that for one of the many range checks I bring along a long plastic tube. He ran the antenna through the tube and used some tape to hold the tube vertical. The next range check was amazing. 350 to 400' before the servos began a slight twitch. I had a couple of whip antennas that I bought in the anticipation that I might need them for my turbine planes so the next time we did a range check we had the receiver set up with one of the whip antennas. No noticeable change to the 350 to 450' range. I now have the whip permanently installed on the plane but it still bugs me that the source of the problem could not be identified. I have not flown this plane since being equipped with the whip antenna so it hasn't been proven 100% as the solution. First flight will be any day now(waiting on retract parts from BVM).