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The B-47 arose from an informal 1943 requirement for a jet-powered reconnaissance bomber, drawn up by the U.S. Army Air Forces (USAAF) to prompt manufacturers to start research into jet bombers. Boeing was among several companies that responded to this request; its initial design, the Model 424, was basically a scaled-down version of the piston-engined Boeing B-29 Superfortress equipped with four jet engines. The next year, this concept evolved into a formal request-for-proposal to design a new bomber with a maximum speed of 550 mph (800 km/h), a cruise speed of 450 mph (725 km/h), a range of 3,500 mi (5,600 km) and a service ceiling of 45,000 ft (13,700 m).
In December 1944, North American Aviation, the Convair Corp., Boeing and the Glenn Martin Company submitted proposals for the new long-range jet bomber. Wind tunnel testing had shown that the drag from the engine installation of the Model 424 was too high, so Boeing engineers then tried a revised design, the Model 432, with the four engines buried in the forward fuselage. The USAAF awarded study contracts to all four companies, requiring that North American and Convair concentrate on four-engined designs (to become B-45 and XB-46), while Boeing and Martin were to build six-engined aircraft (the B-47 and XB-48). The powerplant was to be General Electric's new TG-180 turbojet engine.
By 1956, the U.S. Air Force had 28 wings of B-47 bombers and five wings of RB-47 reconnaissance aircraft. The bombers were the first line of America's strategic nuclear deterrent, often operating from forward bases in the UK, Morocco, Spain, Alaska, Greenland and Guam. B-47 bombers were often set up on "one-third" alert, with a third of the operational aircraft available sitting on hardstands or an alert ramp adjacent to the runway, loaded with fuel and nuclear weapons, crews on standby, ready to attack the USSR at short notice.
Cache approved by Martin Morse, park service specialist.
Remember, park all four tires off the road, don't block any gates and NO speeding.
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