Boeing B-17 Flying Fortress B-17F

The B-17F replaced the heavily framed B-17E nose with a molded one- or two-piece plexiglass cone and adopted broad-blade paddle propellers. Reinforced landing gear let maximum bomb load rise from 1,900 to 3,600 kg, at the cost of cruising speed. Additional wing fuel cells ("Tokyo tanks") extended range by roughly 1,400 km. In combat it proved tail-heavy and inadequately defended head-on, a problem the last Douglas production blocks began fixing with a powered chin turret inherited from the experimental YB-40. 3,405 were built: 2,300 by Boeing, 605 by Douglas and 500 by Lockheed/Vega, including the famous Memphis Belle.