Since the plane only weighs 10.5 pounds go with the 17 x 6 apc. Don't go any larger than 17 inch because the plane is so light and you want to keep your R's up a bit for good transition and throttle setting durring hover. The 16 x 7 apc might be another prop that would work well. Both these props are under propped for this motor. It will be out of the power range of this motor at full throttle but you will like them a lot on your 10.5 pound plane.