The R-985 was a nine-cylinder, air-cooled, super-charged radial aircraft engine first used by the U.S. Army Air Corps beginning in 1932. It featured a 985 cubic inch displacement and turned 2,300 maximum RPM. The earliest versions were rated at 300 horsepower, but subsequent models produced up to 450 horsepower. This engine was used in thousands of military and civilian aircraft of numerous types over the years.