This Magnum 273 3-cylinder radial model airplane engine was manufactured in England, circa 1980s. The engine is 20”-long, 9”-wide, and 9”-high. The Magnum 91S was a single-cylinder, four-cycle, air-cooled model airplane engine that burned methanol on glow ignition. They adapted three of their 91S cylinder assemblies to a common crankcase to produce this three-cylinder radial 273. A few of these radials were converted to burn methanol on spark ignition by utilizing spark plugs and adding a camshaft driven distributor in back. The distributor, which supports a distributor cap provided by Bruce Satra (Utah) was mounted to a movable plate to provide manual adjustment for spark timing.