Hi there all, was hopin someone out there can help. I recently had a 40 TT Super Decathlon built for me. It has completed about ten incident free flights, when after the tenth flight, I just turned it around on the RWY and took off again. As soon as I lifted of it started a very eratic uncontrolled oscilation about all the axes. Needless to say, it got worse until the aircraft crashed. One reaching the a/c I found all the servos jumping around wildly. Now they do not stop chattering and making wild uncommand movements. When I do a range check with the engine off, It is fine until I move about 10ft away, and then it starts gyrating wildly, witht he servos moving way past their full travel ranges. I am aware of metal on metal interferance, however all of the normal fixes have not yet been sucessful. I have a pull pull rudder installed, and was wondering if I had to remove it and replace one of the pull pull wires with a plastic coated wire. I notice that it has the two wires touching. The other possible problem is that I see the throttle linkage is connected directly onto the carb arm. How could all this change after about 10 flights? I am very confused and have just about dismantled the whole model and still found no cure.

Very suspicious for a radio failure. Loss of range, power off, indicates that it's not vibration related. Thoughts include a failed crystal in the Rx, PC board land failure, broken solder joint or lead, internal problem with battery pack like a failed cell, wiring issues with the switch harness, maybe antenna pulled loose from Rx. I would, one at a time, replace the Rx, the switch, and the battery trying to isolate it. Less likely:unplug all the servos and and put them back one at a time. If it works with the first one, keep adding them until you find one causing problems. Try transmitter with another working airborne pack in case it isn't the plane radio that's the trouble. Something seems to have failed in the radio.

I use the same radio to fly my other planes with, without a hitch, so its definitely interferance from the decathlon itsself. Have also tried various crystals and recievers....

It doesn't have to be interference. You could have problems with your receiver too. Since you have other receivers on the same channel, swap one out into this plane and see if you still have the same problem. If not, then the problem is with the receiver. If you do still have problems, then you need to look elsewhere for the problem.

Hope this helps

Ken