MTH R 422-CGThe MTH R 422-CG is an Austrian aircraft engine, designed and produced by MTH Engines of Mattsee for use in ultralight aircraft.Design and developmentThe engine is a twin-cylinder two-stroke, in-line, displacement, liquid-cooled, gasoline engine design, with a toothed mechanical gearbox reduction drive with a reduction ratio of 3.0:1. It employs dual electronic ignition systems and produces at 6500 rpm, with a compression ratio of 12:1.