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
II Bomber Command II Bomber Command The II Bomber Command is an inactive United States Army Air Forces unit. It was last assigned to Second Air Force, based at Fort George Wright, Washington. It was inactivated on 6 October 1943. During World War II, the unit trained large numbers of B-17 Flying Fortress and B-24 Liberator bombardment groups. It controlled operational training units (OTU) and replacement training units (RTU) primarily in the west and southwest of the United States until late 1943 when its operations were taken over by Headquarters, Second Air Force and the command was disbanded. It also performed antisubmarine patrols