GP U Can Do 3D
Saw one fly this weekend with a brand new OS91 4 stroke (not broke in yet).
An acclomplished 3D flyer owned it. I flew it also. The OS91 4 stroke works for this plane.
The plane came out at 7 lbs 10 oz. with some fuel in the tank.
The airplane torque rolled, knife edged, waterfalled, and flat spinned. The owner touched the rudder on the grass also.
The airplane flys very well with the OS91 4 stroke. After watching it fly and flying it this weekend, I would question adding more power.
The owner watched a demo of the airplane fly at Chattanooga and it too was powered by the OS91 4 stroke.
Just my 2 cents. I thought exactly like everyone else concerning the potential lack of power of the OS 91 4 stroke until I saw one fly.