The main difference between the E and F was that wide blade propellers were fitted to the new type that gave better performance. The F was made in greater numbers and had to be manufactured by three different companies; each factory had slight detail modifications. The source factory was listed by a suffix placed after the designation and block number: BO stood for Boeing, VE for Lookheed Vega and DL for Douglas. Thus, a plane with the designation B-17F-109 VE told you that it was made by Lookheed.

The B-17F’s arrived in England in August 1942 and were destined to fly throughout 1943. However by the summer of 1944 they were a rare sight on operational bases. The planes were subsequently re-modifed by the idividual bases to cope with the unique problems that com to light in air combat. The aircraft, designed and tested in warmer climes, had to cope with the extremly low temperatures and high humidity of altitude flight. Problems encountered in the first few missions: the brushes in the electrical generators frozen up, the ball turret would not rotate, guns jammed, there was blind spot in the forward zone of fire and the tail was very heavy.

“To find out at the beginning as us tried as one attacks the B-17 best, tried we bomb to and so on everything, even the bombers bombs. But we found out that the best tactics consisted in attacking her from the front and we used the 190s for it as end of ’43. The time at which you could shoot was very short since the approach-speed was very high. But, when you have hit the B-17 from the front, you have hit the cockpit or the engines mostly. There were only four 190s groups after this time which attacked from behind, which were called the “storm troops”. If the B-17 didn’t burn or the garrison didn’t jump down, then these 190s rammed the bombers at the tail unit or the rudder.”
Walter Krupinski

Bundesarchiv, Bild 101I-657-6304-24 / Meschke / CC-BY-SA 3.0 [CC BY-SA 3.0 de (], via Wikimedia Commons

Bundesarchiv, Bild 101I-657-6304-24 / Meschke / CC-BY-SA 3.0 [CC BY-SA 3.0 de (], via Wikimedia Commons

Weak point

By November 1942, the Luftwaffe fighter pilots had realized that they could attack a B-17F head-on and be safe from return fire from the actual plane. The fitted 0.30-calibre michine gun in the plexiglass nose was ineffective so individual Bomber Groups decided to replace it with the more destructive 0.50-calibre guns. A nose gun installation kit was provided by 8th Air Force Service Command and the importance of a forward mounted turret on a B-17 was impressed upon the manufacturers. The work on converting the nose turret was very slow and could be only be carried on when the aircraft was free from combat commitments. It was not until May 1943 that B-17F’s with a factory fitted nose gun mount landed in Britain.

“The Germans got to the beginning of the war from the side or behind. But they got for a lot counter-intelligence fire at 25 to 30 B-17s. When they found out that the B-17 had less fire strength in the nose, they changed the tactics. You came in V formations of the front. For us it looked like a line, now and then, however, they came in the inverted V and we shot onto the middle which, however, wasn’t in range yet. At the next trace it was a normal V perhaps again and the middle was nearer than the outer positions. These came toward us with really high speed. You came with 400 miles and we flew 160 and fired her with her 20 mm cannons on the cockpits as soon as we were within range in the hope to meet something. One could see coming the 20 mm and one hoped that they didn’t meet. After the attack they shifted and came back. Only if they found a single machine, they were not effective from the front, they then came back from the side or behind. A machine at which one or two engines had failed was alone put on herself and the guys of the air force took their time to hit the fuel tanks on the two fuselage sides.”
Robert Davila, Pilot der USAAF

“At the beginning only the Fw 190 attacked the bombers and the Bf 109 only was used as escort. Most attacks were flown from the front. If the bombers noticed that the 190s came, they often flew a curve from 10 or 15 degrees. This made it hard to come flying up from the front again.”
Walter Krupinski

Several problems

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.

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