Roby: I do not know what you are looking for....so I do not know what you are missing? You mention trimmers, weed wackers ect. Chain saws have much more power. Ever watch a contest how fast a modified one can cut a very big log. In the contest the engine has to start in one pull. Saw is on the ground and operator has to grab saw and start it on a very quick pick it up to cut log. What I am saying our airplane engines got to do about the same thing. That is to start and run strong. I would venture to say your so called dedicated airplane engine builders used much of the same parts and technology. I am very glad there is RC people out there converting engines.... it keeps the big boys from charging anything they want. Thanks Captinjohn