Intrigued by the Morton M5, Bruce Satra considered it to be of sound design, but felt it lacked structural integrity inside. His quest to produce a more robust engine led him to this design that he dubbed the Satra R-5, which was finished in 1984. The bore is .700 and stroke is .625, making the total displacement 1.2 cubic inches compared to the Morton M5’s bore of .625 and stroke of .600 totaling only .920 cubic inches. This engine burns methanol on spark ignition and turns a 15-6 propeller at 6500 revolutions per minute. Unlike the Morton M5 Bruce utilized enclosed rocker boxes eliminating the need for manually lubricating the rocker arms before operation. The engine is 8″-long, 6″-wide, 7″-high, and weighs 2 lbs. 6 oz.
Satra “R-5” Model Radial Airplane Engine
