Barracuda is correct...next time when you mount aileron servos if they are on their sides, then opposite of each other..ie....both facing outboard or both inboard...if they mount flat then the servo arms need to be opposite.......that is of course if your using a single channel for ailerons......if dual channels are being used then reverse one servo on the correct channel to make the ailerons move correctly in relation to the stick on your transmitter