You will be most dissapointed in the final performance levels of any of the 40cc class engines for the P-47. I don't care how you go about putting it together two things are going to happen. You will need nose weight to balance and you will need power to fly it to maintain a comfortable thrust to weight ratio. The same holds very close for the lower class 50cc engines. I'm not speaking of extreme aerobatics, I'm talking about flying it like a warbird.

I'm very familiar with this plane, it's equipment options, weights, and performance. If you always want to be concerned about energy management in the turns, make long take off runs, and do lopsided loops because you had to trade altitude for aispeed, and sweat stalling the plane all the time, get a 40 to 50cc engine. If you want excellent power levels at all times and an average to relativly short t/o run, get a 55 to 62.

Underpower the 47 and it won't be long before it becomes just another smokin' hole in the ground.