Boeing B-17 Flying Fortress Boeing B-17 Flying Fortress The Boeing B-17 Flying Fortress is a four-engined heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). Competing against Douglas and Martin for a contract to build 200 bombers, the Boeing entry (prototype Model 299/XB-17) outperformed both competitors and exceeded the air corps' performance specifications. Although Boeing lost the contract (to the Douglas B-18 Bolo) because the prototype crashed, the air corps ordered 13 more B-17s for further evaluation. From its introduction in 1938, the B-17 Flying Fortress evolved through numerous design advances, becoming the third-most produced bomber of all time,
31st Flying Training Wing (World War II) for most of its operational service, it controlled contract pilot schools primarily in the Central United States. Until 1939, the Army Air Corps provided all flying training with military instructor pilots. Beginning in 1939, it contracted with nine civilian flying schools to provide primary flight training. Primary training consisted of a three-month course of 65 hours of flying instruction. As the United States prepared to enter World War II by expanding its number of flying squadrons, the number of contract primary schools increased. According to the contract, the government supplied students with training aircraft, flying clothes, textbooks, and equipment. The