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
Military history of the United Kingdom during World War II for the launching of Operation Overlord on 6 June 1944. Following Overlord, further direct support was provided to the troop, but Harris eventually succeeded in detaching his command from Eisenhower's control. The striking of German cities resumed. By the winter of 1944, the power of the British and American bomber forces had grown enormously. It was now routine for 1,000 bomber raids to be mounted by both American and British forces flying from the UK. American forces flying from Italy could also put several hundred aircraft above a target. Accuracy had improved, but it was still nowhere near good enough