He's at altitude just like we are. I gave you some wrong info. It's a 20x6 Master Airscrew wood prop on 30% CP heli fuel. Works ok but I think it's a little overloaded. As I said in another thread, I think it's a lot worse to overload these engines than run them a little on the fast side. The mid 8000 range can be exceeded on the low pitch props for fun fly type airplanes because you don't run them fast for extended periods. I would not be afraid to run these at 9500 or better for short periods.