Avistarpilot, the Avistar with an OS 55AX is a rocket! I flew mine for a season with a OS 40 LA then switched to a 55AX, its unreal. I have recently dropped a 40 back into it and added another servo along side the original so i could add flapperons. The Avistar is a real performer with both motors & will lift off with flapperons in under 20 feet even with the 40. I have dozens of planes to fly, but still get a kick out of flying my old Avistar. I have won fun fly events with it, so its not just a trainer.....Gene