Boeing XB-38 Flying Fortress The XB-38 was destroyed and the project was canceled, in part because the V-1710 engines were needed for other projects such as the Lockheed P-38 Lightning, Bell P-39 Airacobra, Curtiss P-40 Warhawk, North American P-51A Mustang, and Bell P-63 Kingcobra fighters. Boeing XB-38 Flying Fortress The XB-38 Flying Fortress was a single example conversion of a production B-17E Flying Fortress, testing whether the Allison V-1710 V type engine could be substituted for the standard Wright R-1820 radial engine during early World War II. The XB-38 was the result of a modification project undertaken by Boeing and Vega (a subsidiary of
RAF Bomber Command aircrew of World War II air gunner to man the mid-upper gun turret although sometimes the gunners would agree to exchange turrets. At the outbreak of war in September 1939 operational Royal Air Force bomber squadrons in Europe were equipped with two main categories of bombers, single-engined Fairey Battle and twin-engined Bristol Blenheim light bombers and Armstrong Whitworth Whitley, Vickers Wellington and Handley Page Hampden medium bombers. Bomber Command aircrew "trades" flying operationally in the early stages of the war were: Pilot – A qualified pilot flew the aircraft and in the Royal Air Force was usually the captain (function not rank) of the crew,