Im running the OS .61FX on mine. I have plenty of pull out power. Im using a 12X6 Zinger on it right now, but im changing it out to a 13X4 the next time I head out. This plane is great, but to anyone building it, I would suggest reinforcing the fues where the horizontal stab sitts. I almost put it in the first flight because it was too weak and caused the entire stab to flutter.