The Boeing Model 299F was originally ordered as a static test bed; however, it was converted to a flight capable aircraft for testing supercharged engines. This converted aircraft was designated Y1B-17A and was one of a kind. A variety of engine installations and configurations eventually led to the bottom-mounted turbo-supercharger, which became standard on the B-17B -- the first production model of the B-17 series of bombers. The turbo-superchargers allowed the aircraft to fly higher and faster than the non-supercharged YB-17. Once testing was complete, the Y1B-17A became the B-17A.
Number built/ converted
Supercharged engine test aircraft
Serial number: 37-369 Notes: Boeing Model 299F originally ordered as a static test aircraft; became B-17A after completion of testing
SPECIFICATIONS: Span: 103 ft. 9 in. Length: 68 ft. 9 in. Height: 15 ft. 0 in. Weight: 37,000 lbs. gross Armament: Five .30-cal. (or .50-cal.) machine guns and eight 600-lb. bombs Engines: Four Wright R-1820-51 turbo-supercharged radials of 1000 hp each
PERFORMANCE: Maximum speed: 295 mph at 25,000 ft. Cruising speed: 183 mph Service ceiling: 38,000 ft. Range: 3,600 miles (maximum ferry range)