This is my second summer with mine. I have an O.S.46AX on mine, and I love it. I put a Bisson muffler on, and cut down the aluminum mount, and used a Top Flite 11 x 6 to get it to balance properly. I could never get comfortable with the flaps, so I cut them off and put the full ailerons back on. Its got a great roll rate now on high. I had to re-do the gear mounting inside the fuselage this spring. Some ply in some strategic places, and all was good again, you would never know it was repaired.