Continental O-470-13A By The O-470-13A powered the U.S. Air Force's Beech T-34A Mentor. This series of aircooled piston engines became available in the early 1950s, and they have also equipped the USAF's Cessna U-3A and many civilian general aviation aircraft. TECHNICAL NOTES: Type: Six-cylinder, air-cooled, horizontally opposed Displacement: 471 cu. in. Horsepower: 225 Maximum rpm: 2,600 Click here to return to the Cold War Gallery.