I am 99% certain that I have found the problem - an incompatibility between Futaba receivers and other brands (some?) digital servos. To summarize; with the Futaba R127 reciever and only the JR8611a servo attached to channel 4, the servo will randomly twitch causing the rudder to jerk violently to the right about two inches. When other servos are connected the "noise" gets on other channels and causes them to twitch as well, most noticeably the right airleron which deflects upward. The combination of these two (rudder right, right airleron up) would cause a sudden roll to the right which is what I experienced. The duration is brief - 1/4 second perhaps, and then the servos return to center. All of this is without any transmitter input from me. On my 2nd flight it appeared that the plane just wanted to roll into knife edge right for no reason. To me that sounds exactly like the result of the glitch I am seeing. I should receive a Fortress 2000 receiver from FMA today. We are then going to perform some oscilloscope measurements of the Futaba R127, FutabaR138 and the Fortress. We'll throw a HiTec receiver in the mix if we can find one. I will post results later.

Bill Gavin