There is a thread started about this plane in sport and pattern. One guy put a YS 140 on it. Said it was way to much power and has trouble slowing down and if he did it again would use a YS 91. One guy put a 120 in his and said the instruction book is correct. The plane will not sit still on the runway and much more difficult to hover with. The instruction book says The OS 91FX
hovers almost as good as the OS 91 4 stroke but motor of choice is the OS 91 4 stroke