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) covered with a hood for "Blind" instrument flying training. Glider pilot schools used Aeronca TG-5As, Taylorcraft TG-6As, and Piper TG-8As unpowered glider conversions of powered light observation aircraft which had similar characteristics to the military gliders under development. 31st Flying Training Wing (World War II) The 31st Flying Training Wing is an inactive United States Air Force unit. It was last assigned to the Central Flying Training Command, and was disbanded on 30 December 1945 at Fort Worth Army Airfield, Texas. There is no lineage between the current United States Air Force 31st Fighter Wing, established on 6 November 1947