Boeing YB-40 Flying Fortress Boeing YB-40 Flying Fortress The Boeing YB-40 Flying Fortress was a modification for operational testing purposes of the B-17 Flying Fortress bomber aircraft, converted to act as a heavily armed gunship for other bombers during World War II. At the time of its development, long-range fighter aircraft such as the North American P-51 Mustang were just entering quantity production, and thus were not yet available to accompany bombers all the way from England to Germany and back. Work on the prototype, Project V-139, began in September 1942 by converting the second production B-17F-1-BO (serial number 41-24341) built. Conversion work was
38th Flying Training Wing (World War II) in advanced (Phase III) two and four engine training, along with bombardier training and before June 1944, glider training. Graduates of the advanced schools were commissioned as Second Lieutenants, received their "wings" and were reassigned to Operational or Replacement Training Units operated by one of the four numbered air fores in the zone of interior. As training requirements changed during the war, schools were activated and inactivated or transferred to meet those requirements. The schools of the wing used a wide variety of planes to support its numerous training needs: 38th Flying Training Wing (World War II) The 38th Flying