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One of
the most famous combat aircraft - and almost certainly the most famous bomber - ever built,
the B-17 is most closely
asssociated with the epic daylight bombing campaign conducted
by the United States' 8th Air Force against the Third Reich, and
now tends to be thought of exclusively as a strategic bomber.
It can therefore be a surprise to learn that the B-17 was in fact conceived as a maritime patrol and anti-shipping aircraft. The original specification arose out of the tactical theories of those - such as the outspoken W. Mitchell - who argued that enemy fleets could be destroyed by high-altitude bombing, and that the large warship (in particular the battleship) had been made obsolete by the invention of aircraft. Mitchell and his team had demonstrated in the 1920s (in a series of tests conducted using derelict warships, most notably the ex-German Ostfriesland) that even a heavily-armoured capital ship could be destroyed by high-altitude bombing - at least, that is, if it was stationary and unable to defend itself. In 1934 the US Army Air Corps issued a specification for a multi-engined anti-shipping aircraft. A two-motor design was expected, but Boeing came up with a design for a four-engined aircraft able to carry the same bomb load faster and higher. This aircraft had Pratt & Whitney Hornet engines (each producing 750 horsepower), a crew of 8, and internal stowage for eight 600-lb bombs. Designated the '299' it first flew on 28 July 1935. The first of the service-test batch of 13 YB-17s was delivered in January 1937, powered by the Wright Cyclone engine. All subsequent models were equipped with turbocharged engines giving improved high-altitude performance. The first production model - the B-17B of June 1939 - had a different nose configuration, and a larger rudder and flaps. The B-17C had more guns, better armour, and self-sealing fuel tanks. Twenty of the B-17C were supplied to the UK. 90 Squadron of Bomber Command used them in a few high-level bombing missions over German-occupied Europe. It was, however, found that the Norden bomb-sight tended to malfunction, the Browning machine-guns to freeze at high altitude and that German fighters would attack from astern in a defensive blind spot. The improved B17-D bore the brunt of the heavy bomber's early fighting in the Pacific. Extensive combat experience led to the B-17E, with powered ventral ("ball"), dorsal and tail turrets, a huge fin for high-level bombing accuracy, and a great increase in armour and other equipment. The B-17E was the initial weapon of the the US Eighth Air Force, and on 17 August 1942 opened the gruelling two-and-a-half year daylight bombing campaign against German industry. However, the E was quickly displaced by the B-17F, which had a clear plexiglas nose, paddle-bladed props, and provision for underwing racks. 3,405 of the B-17F were built. At the end of 1942 came the final bomber version - the B-17G. This variant was equipped with a chin turret and flush-mounted staggered waist guns, giving a formidable armament of thirteen 0.5" Browning machine-guns. When the bombers succeeded in maintaining tight formation the massed Brownings presented a daunting - and very dangerous - obstacle to attacking fighters. A total 8,680 of the B-17G were built,
the Seattle plant alone turning out 16 per day, and
Data
B-17G - profile drawingThe B-17 Fortress in the Pacific WarCombat Aircraft of the Pacific WarBattles of the Pacific War GuadalcanalThe Battle of the Philippine SeaThe Battle for Leyte Gulf |