Boeing B-17 Flying Fortress NAN10-50.jpg|thumb|B-17 modified for testing of the [[Pratt & Whitney T34|XT-34 turboprop]]. When testing concluded, the aircraft was restored to stock configuration as the "[[Liberty Belle (B-17)|Liberty Belle]]", but was lost in a post-forced-landing fire near [[Oswego, Illinois]] on 13 June 2011.]] [[Category:Boeing aircraft|B-17 Flying Fortress]] [[Category:United States bomber aircraft 1930–1939]] [[Category:Four-engined tractor aircraft]] [[Category:Low-wing aircraft]] [[Category:World War II bombers of the United States]] [[Category:Boeing B-17 Flying Fortress| ]] [[Category:Aircraft first flown in 1935]] 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
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