I have an OS 50 with a Mac header and pipe on mine turning a 12X4 wood prop at right at 16000rpm on the ground. It will hold a hover ant about 1/3 power. This give plenty of power left to get out of trouble. Most of the guys that I fly with a running OS 46 with pipes with 11X4 props at right at 16000rpm on the ground having good luck. We moved our bat. back behind the servos and then I made mine a little tail heavy with a full tank of fuel get all the movement you can get on all surfaces and use the Ele to Fla mix maxed out and she will hover like crazy!!!!!!!!!

Nothing like a little extra power when you need it.