i had a h9 cap with a irvine 1.5, apc 16x8 prop, a little over 12lbs, and it wouldnt hover to save its life, the irvines are probably the best running engine, but just not as powerful as the os's and ys's. Best bet, get an os 1,6, ys 1.4, or even a saito 1.8 if you dont mind a gas guzzler. I currently have a h9 cap with a super tiger 2300, 12lbs, ys 20/20 fuel and apc 17x8, unlimited vertical, but has a perry pump and carb, just my opinion, good luck, here the sig cap is a very nice aircraft