The Toolman: This plane weighs roughly 4 1/2 to 5 or so pounds. None the less, I have seen a .61 sized engine on a Twist 40 (a Super Tiger, I think). It looked like it was a little too big for that size of plane. It flew very well, with unlimited vertical. But then again, the pilot told me that he wasn't into 3D flying, just wanted an affordable plane for sport. I think the weight of the engine will put the CG a little too far forward, without adding some weight to the tail. You'll probably end up with something heavier that won't float as well, with some reduced 3D capability, and you will have to carefully manage your airspeed. You will want a lower pitched prop for the proper amount of torque at the reduced speeds these planes require, and you will need to land hotter.

NorfolkSouthern