Be careful of the engine chosen. Patrick himself said (may be in the instructions) that the plane was designed 120 size engines and vibration could be a problem. Pull your fuselage out and look at the firewall. Mine was lite-ply. I've flown with a YS120 and a YS140. Patrick talks about using up to a YS140L but admitted that some people ran with up to 30cc gas, but that all planes have their limits. It flies lighter than other planes designed for gas.