I almost forgot, I use 22-12 props while most other pilots use 10 inch or less pitch. The 22-12 size gives me much better top speed and excellent vertical climb (2-3 vertical rolls). Reed valve motors like the DA deliver their horsepower and torque peak at lower RPMs while piston port and crankshaft valve motors favor higher RPMs (they work best with smaller diameter and lower pitch). When you under-prop a reed motor you don't get any where near the power it can produce. They will wind up to 8000 RPMs but the HP and Torque is lower at those crank speeds than equivalent crank ported motors (front crank port or rear rotor valve) this last is the best with all prop sizes. For any given prop size a crank port motor will wind it higher than a reed valve motor. Reed valve motors give better low speed and idle performance and if you lug them with big high pitch props they can surprise you with what they will do.