The Great Planes [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJSX0&P=ML]Giant U-Can-Do[/link] weighs about 13lbs.

Multiply 13lbs x 100 watts/lb for good aerobatic performance or by 150-200 watts/lb for 3D performance.

If we use 13lb x 175w/lb we get a power level of about 2300 watts. This is the motor class that you will need.

One possible solution is the [link=http://www.hobby-lobby.com/brushless-axi5330.htm]AXI 5330/18[/link] motor on a 10s Lithium pack capable of delivering 80amps. Use a 20" or 21" APC thin e-prop found [link=http://www.hobby-lobby.com/elecprop.htm]here[/link] at Hobby Lobby.

Good luck!