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
Military history of the United Kingdom during World War II fastest fighter became one of the central themes of World War II. The RAF underwent rapid expansion following the outbreak of war against Germany in 1939. This included the training in Canada of half of British and Commonwealth aircrews, some 167,000 men in all. The RAF also integrated Polish and other airmen who had escaped from Hitler's Europe. The combined bomber offensive was born out of the need to strike back at Germany during the years when the United Kingdom had no forces on the continent of Europe. Initially the bomber forces available for attacks were small, and the rules