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
31st Flying Training Wing (World War II) covered with a hood for "Blind" instrument flying training. Glider pilot schools used Aeronca TG-5As, Taylorcraft TG-6As, and Piper TG-8As unpowered glider conversions of powered light observation aircraft which had similar characteristics to the military gliders under development. 31st Flying Training Wing (World War II) The 31st Flying Training Wing is an inactive United States Air Force unit. It was last assigned to the Central Flying Training Command, and was disbanded on 30 December 1945 at Fort Worth Army Airfield, Texas. There is no lineage between the current United States Air Force 31st Fighter Wing, established on 6 November 1947