The Pobjoy R is a British seven-cylinder air-cooled radial aircraft engine designed and built by Pobjoy Airmotors. Introduced in 1926, it was a popular engine for ultralight and small aircraft in the 1930s. A notable feature of the Pobjoy R was the propeller reduction gear which allowed the small engine to operate at more desirable higher speeds. The engine was license produced in Czechoslovakia by Walter Aircraft Engines as the Walter Mira.