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,
Boeing B-17 Flying Fortress misgivings by the RAF that attempts at daylight bombing would be ineffective. As use by Bomber Command had been curtailed, the RAF transferred its remaining Fortress I aircraft to Coastal Command for use as a long-range maritime patrol aircraft, instead. These were later augmented in August 1942 by 19 Fortress Mk II (B-17F) and 45 Fortress Mk IIA (B-17E). A Fortress from No. 206 Squadron RAF sank U-627 on 1942, the first of 11 U-boat kills credited to RAF Fortress bombers during the war. The RAF's No. 223 Squadron, as part of 100 Group, operated a number of Fortresses equipped