Gas engine for H9 EDGE
There is nothing wrong with the design of the H9 Edge 540. The only problem is that some of the planes have been coming with warped wings or with leading edges that do not match. It is not the round leading edge that is causing the stalling. Actually a blunt leading edge is more stall resistant than a sharper one.
Ditto on keeping this plane light. Try to stay under 13 pounds for good performance. The one that I have has an OS 1.60 FX w/slimline pitts muffler running an 18x6W APC. I have fully unlimited vertical with this combo on 5% fuel. My plane weights in at 12.25 pounds and it performs 3D very well. It does not have any tendicy to tipstall. It just mushes forward in a stall. Very easy to control elevators and harriers. This plane does a perfect wall. It seems to rotate on the wings cg. In all I believe this to be one of the best 1.20 size planes for 3D.