perkinsm...Dave Quatse, our local 3D Ace uses S&W 10% fuel and a 14x6 prop. This guy is good and he will tell you he went through 5 planes until he could tail touch. He also has a gyro on the rudder.
He started out with a .46 engine and finally found that with the O.S. .91 he was pulling out of a hover with authority.

Regards, FRED