Y1B-17A

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.

The Army Air Forces first ordered the aircraft as a static test bed, but it was converted to a flight capable aircraft for testing supercharged engines. The converted aircraft was designated Y1B-17A and was one of a kind. The B-17 prototype flew on July 28, 1935, as Boeing Model 299. 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.

After the loss of the Model 299, the Boeing Aircraft Co. was dropped from the Army Air Corps competition for a new bomber; however, the cause of the Model 299 crash was determined to be pilot error -- the pilot took off with the elevator lock still engaged. The Army leadership was convinced the aircraft had the potential to fill the long-range bomber requirement and ordered 13 service test aircraft (Boeing Model 299B) as Y1B-17 in 1936. The Y1 (instead of Y) indicates a funding source outside of the normal fiscal year procurement. The designation changed to YB-17 on Nov. 20, 1936, before the first aircraft flew.

The Second Bomb Group based at Langley Field, Va., took delivery of the first YB-17 on March 1, 1937. General Andrews (Commander of the Army's General Head Quarters Air Force) wanted heavy bomber techniques developed as quickly as possible so all but one of the 13 YB-17s ordered were assigned to the 2nd Bomb Group. The 13th YB-17 was the only aircraft actually used for extensive flight testing. It was assigned to the Material Division at Wright Field, Ohio.

Gen. Frank M. Andrews, commander of General Headquarters (GHQ) Air Force, wanted heavy bomber techniques developed as quickly as possible, so 12 of 13 Y1B-17s built were assigned to the 2nd Bomb Group, Langley Field, Va., beginning in March 1937. In addition to long-range bombardment, the Army was assigned coastal defense duties as outlined in the MacArthur-Pratt agreement of 1931. This allowed the U.S. Navy to assume long-range sea offensive operations.

Col. Robert Olds, commander of the 2nd Bomb Group, developed a "training mission" in which a flight of B-17s (the Y1B-17 was redesignated B-17 when assigned to the 2nd Bomb Group) would intercept a ship at sea to demonstrate the long-range bomber's capabilities. The ship selected for intercept was the Italian liner "Rex." On the morning of May 12, 1938, three B-17s took off from Langley Field under the command of Maj. Caleb Hayes. Lt. Curtis LeMay was lead navigator for the flight and charged with finding the liner, which was about 800 miles east of New York City.

Although the weather was bad, the B-17s successfully intercepted the "Rex" after a four-hour flight. The B-17s made several passes over the ship to allow for still and motion picture photography. The U.S. Navy protested that the flight was not coastal defense, but the U.S. Army made the most of the flight and heavily publicized it in news reels and newspaper stories.

Type Number built/ converted Remarks Y1B-17A 1 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) Type Number built/ converted Remarks Y1B-17 13 Service test aircraft Serial number: 36-149 to 36-161 SPECIFICATIONS: Span: 103 ft. 9 in. Length: 68 ft. 9 in. Height: 15 ft. 0 in. Weight: 34,873 lbs. gross Armament: Five .30-cal. (or .50-cal.) machine guns and 8,000 lbs. of bombs Engines: Four Wright R-1820-39 Cyclone radials of 930 hp each PERFORMANCE: Maximum speed: 256 mph at 14,000 ft. Cruising speed: 175 mph Service ceiling: 30,600 ft. Range: 3,320 miles