I don't know if I still have the manual, but absolutely use 75 oz.in. or better metal gear servos. I lost mine in a blender when a 55 oz.in. plastic gear servo stripped out and locked into place fully deflected. It hammered into a huge rock pile and shoved the engine through the fuselage the long way.

The plane is fully 3D capable and flys well with anything 1.48 or larger in glow. I saw a couple that were waaayyy overpowered with gas engines and the wing tips would twist in tight turns at power. I'll have to say that they both had 45 and 50cc engines and it was much too much.

The plane is extremely well built, but could use a little reinforcemenmt at the landing gear plate. That was the only manufacturing problem I had with mine. Use 4/40 hardware at all control surfaces. It matters with this plane.