My .53 spent its first year on an RCM 40 trainer, the 12x6 three blade held the rpm to 10,800, it would easily pull the plane at half throttle and got fantastic fuel ecomomy, it was not overloaded with the 12x6 three blade because a 13x6 is one of the recommended props. A Webra .50 is another very user friendly engine that is real easy to tune, light and reliable.