[8D]I have a Magnum .52FS on my Kaos, and it is a good combination for power; however, the extra weight caused the plane to be nose heavy requiring using an old AA nicad in the tail as a weight. Also the throttle cable is set up for a two stroke and required considerable effort to reroute. If I were doing it again I would use a .45 to .51 two stroke. I had a kit built Kaos with a .47 on it years ago and it was a fine combination.

Mike H.