B-17F
The failure of the ball turret was of greater concern on the early models. Apart from the problem with retaion, the oxygen line, throat microphone, and flying suit heater cords all became tangled during normal combat operations. The gunner also feced the risk of running out of oxygen. The bottle contained insufficient oxygen for a normal mission and it was the job of the waist gunner to re-charge the ball turret cylinder but the valve often froze open and supply quickly emptied.
Other Problems included a leaking hydraulic unit, and a turret door that was prone to cracking. Getting out of the turret in an emergency was also a painfully slow procedure. The gunner had to hand-crank the turret in to the correct position, then lift himself out of the hatch and put on a parachute. Needless to say ball turret gunner was the least popular job amoung B-17 crews.
By May 1943, the US VIII Bomber Command had listed a dozen priorities for standard modifications: nose gun fittings, upper turret charging handles, armor plate protection for the pilot's panel, more ammunitin for the gun in the radio room, an increase in the oxygen supply to all turrets, new radio antennae, Mark III IFF sets, a remote indicating compass and a life-raft realease. there was also a list of less important changes such as bullet proof glass in windows, re-locating waist gun sites for a better field of fire, fitting of GEE and changes to the oxygen system.
The cold conditions the aircraft operated in tended to freeze the bomb bay doors and the bomb shackles. In early missions this problem was overcome by one of the crew using a crow bar on on the frozen mechanism. Experienced crews would test the bomb bay door operation before they were on the bomb run.
Nothing could be done to stop the plane from being tail heavy but crews were warned about storing equipment and ammunition near the rear.
Another cause for condern was the ability of the waist gunners to inadvertently fire into the wing and tail. In July 1943 an electrical cut off system was fitted which automaticlly stopped the gun firing pins if the gun was aimed at any part of the plane.
One of the most important changes in the development of the B-17F was the addition of extra fuel tanks giving the plane another 1080 US gallons. effectively, this increased the B-17F's range by 1000 miles and the operational radius doubled to 650 miles. The extra fuel units were called "Tokyo Tanks" (supposedly adding enough range so that a B-17 could get to Tokyo from a carrier in the Pacific) and were made up of nine rubber self-sealing cells placed betwenn of ribs of both wings. These long-range versions first appeared at English bases in May 1943.