The B-17G was the final production version of the Flying Fortress and was produced in greater numbers than every other version put together. A total of 8,680 B-17Gs were built, 4,035 by Boeing, 2,395 by Douglas and 2,250 by Vega. The early B-17G was actually very similar to late production B-17Fs. The main difference was the adoption of the Bendix remotely sighted chin turret, adopted on the last 86 B-17Fs. On early B-17Gs this replaced both the nose guns and the cheek guns, but the cheek guns were soon restored. The bulging cheek gun positions used on the B-17F was reintroduced later in the production run (Douglas block 25, Vega block 35 and Boeing block 60).
The waist gun positions were fully enclosed, with the gun mounted in the middle of a Plexiglas window. At first the two waist positions were level with each other, but on later production they were staggered to give the gunners more space. The radio compartment gun was also enclosed, before later being removed altogether.
When fully armed the B-17G carried thirteen guns (two in the tail, two in the lower ball turret, two in the roof turret, two waist guns, two in the chin turret, two cheek guns and one in the radio operations position), only one less than the XB-40.
The B-17G first flew on 21 May 1943, and production aircraft began to appear in July. Before entering service they were then modified, either at the United Air Lines Modification Centre at Cheyenne, or at Field Modification centres in England. One of the best known modifications introduced at Cheyenne was the “Cheyenne” tail turret. This was designed to improve the field of fire of the tail guns. The gunner’s position was redesigned, with much larger windows. The guns were moved nearer the gunner, reducing the length of the aircraft slightly, and the mounting was protected by a semi-circular cover.
A number of B-17s were converted into SG-17 air-sea rescue aircraft. This involved replacing the chin turret with the housing for an air to surface vessel (ASV) radar set and carrying an air droppable lifeboat under the fuselage.
Engine: Wright R-1820-97
Horsepower: 1,000hp at 25,000ft
Span: 103ft 9 3/8 in
Length: 74ft 3.9in (with “Cheyenne” tail)
Design Weight: 48,726lb
Maximum Weight: 65,500lb
Max Speed: 302mph
Cruising Speed: 160mph
Range: 3,400 miles
Armament: 12 or 13 .50in machine guns
Bomb load: 6x1600lb (9600lb) or 2x4000lb (8000lb)