saito 91 on flip 3d
I wouldn't recommend it. Too much weight and you don't need the extra power. Keep the Flip 3D as light as you can.
A YS 63 or Saito 72 or O.S. 50 SX are the engines of choice and will be plenty of power. I have the YS 63 on mine and it will hover at 1/2 throttle.
Jim