Again Dan............the plane is not complete so the engine is not running. All that is installed are the servos, the engine and the two control rods going from the engine to the servos. I'm thinking there is some kind of physical strain going on but I can't figure what it would be. The servo is mounted to hardwood with the usual grommets in rubber but that's all. I've set the endpoints both equally from center so there is no adverse travel for the servo.