Irvine is a great Mojo 40 engine I like the Kit build better then the Arf, I get to tweak and cut wieght. But I have a 40 ARF that is top quality and flies fine, and so far has taken two hard dorks no problems[8D]


That 72 won't be nowhere near 3/4 throttle to hover a 4-4.5 lb MOJO 40, as I said many perfer it over a 82.
Twist may be heavy or you didn't have it proped well.