RE: H9 Twist 40 engine and prop choice???
Nubie, Shouldn't be a problem with that size prop. I have a Saito 72 on mine with a 13x4w. Plenty of clearance. I'll have to say that so far my Saito hasn't worked all that well on this plane so I'm glad to see that others have had good success with the 2 strokes mentioned. I may have to switch......[:-]