John Thompson, of Kansas, employed some Saito 120 model airplane engine cylinder assemblies for this radial, but from that point on it is his design. Each cylinder has its own pair of cams that operate the inlet and exhaust valves. It weighs in at 28 pounds and has a 1.25-inch (32 mm) bore and a 1-inch (24.8 mm) stroke with a total displacement of 10.8 cu. in. (180 cc). Initial tests with a 28-14 propeller indicated it produces 18+ horsepower. John incorporated a Borg Warner 1SH`1 2-inch, 10-blade turbocharger compressor for fuel distribution and atomization located within the intake manifold in the rear of the engine. It runs on glow ignition and burns gasoline with oil mixed in for lubrication. It also sports his custom designed hydraulic controlled variable pitch propeller. The engine is 14″-long, 28″-wide, and 14″-high.
Below you can watch a video of an engine just like this one running. It was built by Pete Palmquist and Duane Treiber in 1998 at Custom Mold Tool Shop.