bought one used,old model,very heavy,put an os 91 with pump,was not enough motor,then put a saito 180,that did it,hot but easy landings .The modeler who built it put ailerons on the top wing also,I had to move the elevetor and rudder servo to the tail,also made a hutch for the battery under the tail to balance it,(to long nose).it was build like a tank,(over built).like biplanes.