Im thinking a bb abc type engine is what im gona go with. alse I have a os la-.46 that has a vibration problem. I took it to the field and asked what people thought was wrong with it. they all thought it had a bent shaft, and it needed a new shaft to run right. I might put the tt .42 gp back on until I can locate the parts for cheap. this has me kinda peeved at this point with all the troubles with the club and the airplane servo problem and now this. Aaargggg, this was supposed to be fun.