I flew the Great Planes Gene Soucy Extra last year on that engine and did well but I'm at 400'. It a beautiful flying plane and presents very well. Mine had no coupling at all in knife edge, inverted was just a breath of down and I was completely setup exactly as the manual recommends. I think I came in at 13lbs even using the slimline muffler

http://www.towerhobbies.com/products.../gpma1365.html

And there is a review here on it which includes video doing 3D work. I never did do any 3Dwith mine so I cannot help there

http://www.rcuniverse.com/magazine/a...article_id=262