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
RAF Bomber Command aircrew of World War II recognized emergency landing place. Vigilance was always maintained as Luftwaffe night fighters flying as "night intruders" sometimes followed the bombers home and attacked as aircraft came into land. If the conditions were foggy, or particularly poor on their return it was not unusual for aircraft to be diverted to more distant bases which were clear. Arriving back at base crews were promptly ferried to de-briefing where mugs of tea were distributed while each crew was interviewed and a detailed operational report, compiled before a generous bacon and egg breakfast could be claimed. From the outbreak of war RAF Bomber Command