An air-cooled vertical model engine I designed in 1990. It is entirely fabricated construction in steel and aluminum, although others have made it completely of brass. Both valves are cam and rocker actuated, and the carburetor is a throttling type. The counter-balanced crankshaft has the connecting rod slinging oil in the enclosed case. Plans for construction of this engine were also published in Strictly IC magazine in 1998, and modelers have built many of these. It starts easily with a cord around the fly wheel pulley and is quite lively in throttle response. I added the intake filter on my original for outdoor running at dusty gas engine meets. Bore of this engine is 3/4-inch and stroke is 7/8-inch.
Photo by Dick Upshur