I didn't put a tach on it.....so I don't know for sure an exact speed. But just listening to it by ear, it is higher than I would like it to be........if that makes sense. Like I said, I am rarely above half throttle, and even then it is screaming. I did I few high speed fly-bys today.....and I was waiting for something to break inside the motor. I'm thinking that by swinging the bigger prop, the rpms at half throttle should be lower than with the smaller prop at same throttler setting.