Thats a lot of engine for the 25% H9 Cap 232.

Maybe you should look for a 35--40cc engine for it. That 3.7 is about 60cc!!! You could use that on a 28% plane with an 80--90" wingspan.

I'm not sure your going to like the way the little 25% Cap flies with that heavy of an engine up front.

I flew my H9 Cap with a ST3000 at 6000' elevation and it was a monster. It weighed 11.75 pounds and would hover at about 3/4 throttle. Pretty darn good when you read the posted weight of a lot of the H9 Caps.

I really wouldn't put that much engine on that plane if I were you. Trust me--I'm all about HP and hovering. Too much HP is just about right. You DON'T have to fly it at full throttle. With that engine on the firewall---you'd better not fly it at ful throttle. You'll rip it apart. You've got a pretty darn heavy engine there, and you could easily get the Cap to hover and fly 3D very well with an engine that weighed significantly less.

Save the 3.7 for an 80"+ plane and get a 35--45cc engine for the 25% Cap.