A member of my club bought an early version of the RCGF 15 and had the following experience:Crank shaft threads shredded,( repaired by the company), Carburetor problems ( company furnished new carb.), after which he flew the engine for the next two seasons with no problems. Dependable and excellent power when broken in properly. His was an early engine and obviously had teething problem which I would judge to be resolved in later engines. My.02.