I flew an OS 108 powered CG Ultimate for several years. It would easily do knife edge loops and had plenty of power BUT, and a big But, it was heavy and when you cut the power it came down like an elevator. It was not easy to land because of the high sink rate caused by the extra weight and high drag natural with biplanes. I think it would have been much more enjoyable to fly with a bit less power and weight. Just my opinion.