also the ailerons have separate servos so there not connected like most trainers with single servo setups and can sag when the power is off . having a servo for each aileron gives more control authority . that plane in the foreground has a DA 150 which is a 2 cilinder gas engine which means there are probably 2 servos on each surface in the wing and 2 or 3 servos on each of the other surfaces with a pull-pull set up $$$$$$