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,
B-17 Flying Fortress units of the United States Army Air Forces B-17 Flying Fortress units of the United States Army Air Forces This is a list of United States Army Air Forces B-17 Flying Fortress units of the United States Army Air Forces including variants and other historical information. Heavy bomber training organizations primarily under II Bomber Command in the United States and non-combat units are not included. The B-17 Flying Fortress was perhaps the most well-known American heavy bomber of the Second World War (1939/41-1945), . It achieved a fame far beyond that of its more-numerous contemporary, the Consolidated B-24 Liberator. The first pre-production Y1B-17 Fortress was delivered to the