The B-17F was the first version of the Flying Fortress to be built in really large numbers. A total of 3,405 aircraft were built. Production was subcontracted to Douglas, who built 605 aircraft, and Vega, who built 500, with Boeing producing the remaining 2,300. The most obvious visual change was the replacement of the framed nose with a rather point pointed frameless Plexiglas nose. The B-17F was also given paddle-blade propellers to improve high altitude performance. Internally there were around 400 minor improvements. The aircraft also carried an additional 1,100 gallons of fuel in “Tokyo tanks” installed in the wings. The use of Wright Cyclone R-1820-97 engines meant that despite the extra weight, the B-17F was the fastest version of the aircraft, with a top speed of 325mph. The B-17F was the standard production version of the aircraft for most of 1942 and the first half of 1943.
Early B-17Fs carried the same arrangement of guns as the B-17E. A single 0.30in gun was carried in the nose. A total of eleven 0.50in guns were carried, two cheek guns, two waist guns, two in the ball turret, two in the tail, two in the upper turret and one in the radio compartment. Later aircraft replaced the 0.30in nose gun with a mounting that could carry one or two 0.50in guns, for a potential total of 13 guns. The cheek guns were initially carried in flat windows, but this did not allow them to fire forwards, and so bulged cheek gun positions were added, at first at modification centres, and then as standard from Boeing production block 55 onwards. Finally, the Bendix chin turret normally associated with the B-17G was added to the last 86 Douglas built aircraft, starting with block-75, giving the aircraft a total of 15 guns.
The B-17F could carry up to eight 1,000lb bombs or twenty four 100lb bombs. Part of the increase in bomb load was due to the addition of bomb racks capable of carrying one 1,000lb bomb under each wing, between the inner engine nacelle and the fuselage. These were added from Boeing production block 30 and Vega and Douglas blocks 20. The normal bomb load remained 4,000lb
The vast majority of B-17Fs served with the Eighth Air Force in Britain or in North Africa. Nineteen were delivered to the RAF from August 1942, where they served as the Fortress II with Coastal Command.
Engine: Wright Cyclone R-1820-97
Horsepower: 1,380hp (war emergency setting)
Span: 103ft 9 3/8in
Length: 74ft 8.9in
Design Weight: 40,437lb (early), 48,726lb (late)
Maximum Weight: 56,500lb (early), 65,500lb (late)
Max Speed: 325mph
Cruising Speed: 160mph
Ceiling: 37,500 feet
Range: 2,800 miles (early), 3,800 miles (late)
Armament: Eleven 0.50in machine guns plus one 0.30in gun.
Bomb load: 8,000lb