Boeing B-17 Flying Fortress B-17B

The B-17B (Boeing model 299M) was the first genuinely production version: over the B-17A it added a larger rudder and flaps, a redesigned nose and 890 kW R-1820-51 engines. The Y1B-17's globe-like nose turret was replaced by a single machine gun poking through a ball-socket in the new glazing. It first flew on 27 June 1939; 39 were built in a single production run, spread across several serial-number batches because of the tight budgets of the time. In October 1942 in-service B-17Bs were redesignated RB-17B and moved to training and transport duties.