Hey Capt,n, my apologies to hamaoki if I was blunt, I really did not mean to be. Maybe I overstated my thoughts. Yeah I hate cleaning planes too. But my 4 strokes are not too bad if you route the exhaust and breather the right direction, I realize some times it is not possible though. My later OS and Magnum engines recirculate it back into the intake which takes care of the breather problem. Hamaoki hang in there with your work! We all leave our experiments open to critical comments, these comments can be constructive. I think the jist of my reply was about the complexity. If you are flying larger 4 strokes, why not mod the rod and crank and run gas/glow?