<p>The first swept-wing jet bomber, the B-47 provided the US Air Force with a quantum leap in operational capability thanks to the enormous technological advances made by the Boeing team. For many people it is the epitome of grace and beauty in aircraft design—a design that was to find many uses during its illustrious service career.
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<p>On 17 December 1947 there took place a flight that revolutionized bomber aviation: the Boeing XB-47 took to the air for the first time. Its swept-back wings and its six engines underslung in pods beneath and its sleek, slim fuselage brought the first real jet age bomber design into being. Additionally, the high speed of the aircraft brought the world's manufacturers of fighter aircraft to attention, for the XB-47 was capable of outrunning the majority of fighter aircraft that had appeared up to that time.
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<p>The newly established US Air Force had looked upon the design with favor and ordered two prototypes into production. The bomber was originally powered by six General Electric J35 engines, each of which developed 3,750 lb (16.68 kN) of thrust. The 35-degree sweptback wing was thin and, combined with the extremely high aspect ratio of 11, it provided a very fine aerodynamic efficiency. However, this lack of depth made it impossible to house the landing gear or the fuel tanks in the wings. The final solution for the landing gear was a tandem gear or 'bicycle' arrangement. One two-wheel main gear was installed just forward of the bomb bay, and the second was installed just aft of the bomb bay. Small outrigger gears were incorporated into the inboard jet engine pods to provide lateral stability on the ground. Fuel cells were built into the fuselage above and aft of the bomb bay.
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<p>The aircraft normally carried a crew of only three: a pilot and co-pilot housed under the fighter-type Plexiglas canopy, and the navigator-bombardier who flew in the forward nose compartment.
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<p>The US Air Force ordered the aircraft into production in September 1948. The first 10 B-47As were to be considered non-combat types and were utilized for development and training purposes. The first B-47A flew on 25 June 1950. However, even the B-47A had changed powerplants: General Electric J47 engines each developing 5,200 lb (23.13 kN) of thrust replaced the J35s which were utilized on only the first prototype.
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<p>The first true combat model of the B-47 was the B-47B variant. This aircraft was fitted with six improved J47-23 jet engines. The clear Plexiglas nose had been closed, the size of the bomb bay had been reduced and to assist the slow development of jet power the aircraft was fitted with 18 1,000-lb (4.45-kN) thrust solid-fuel rocket (or JATO) units. Twin 0.5-in (12.7-mm) machine guns in the tail (and entirely radar-controlled) comprised the defensive armament.
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<hi style=hdr1>Quantity Production</hi>
<p>The B-47 Stratojet rapidly became the backbone of the USAF's Strategic Air Command, and before the production lines were shut down 2,289 of them had been produced. Quantity was such that the Boeing plant in Wichita, Kansas, could not undertake the building of the entire order. While the Wichita aircraft were designated B-47-BW, B-47s manufactured by Lockheed in its Marietta, Georgia, plant were designated B-47-LM and aircraft produced by Douglas in its plant in Tulsa, Oklahoma, were designated B-47-DT.
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<p>The first B-47B delivered to SAC went to the 306th Bomb Wing at MacDill AFB, Florida, on 23 October 1951. Before the end of the line the B-47 equipped 36 SAC wings, one MAC wing and various other small units in the USAF. The units each comprised 45 aircraft. It took until February 1953 before the 306th BW took part in its first simulated combat operation. During that month the bombers pioneered the first SAC deployment to England. Staging through Limestone AFB, Maine, the B-47s flew on to RAF Fairford in England. Before the initial deployment had been completed the indoctrination flight record had been broken nine times. The best time recorded was 5 hours 22 minutes from Limestone to Fairford, an average of 575 mph (925 km/h).
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<p>These rotational flights became policy in SAC and one B-47 unit was on duty in England for a 90-day period at all times. This rotation program continued until 1958.
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<p>The year that saw the new B-47E joining SAC was 1953. The B-47E was an extensively modified version of the aircraft. New and improved engines were installed which increased individual engine thrust to 6,000 lb (26.69 kN). Additionally, a water-injection feature had been added which raised the thrust to 7,200 lb (32.03 kN) for take-off. The later B-47E models also did away with the internal JATO units and incorporated 33 external units on a rack which could be jettisoned following take-off. An improved tail gun position was installed which utilized two 20-mm cannon replacing the earlier twin machine guns.
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<p>During this time another development of the aircraft was made that would become quite notable as the RB-47E began coming off the production lines. This long-nosed version of the aircraft was built for a completely different mission: long-range photo-reconnaissance. Numerous cameras were installed at various points in the fuselage, and in some versions of the aircraft crew members for electronic countermeasures and reconnaissance specialities were housed in what had been the bomb bay. The RB-47H and ERB-47H were electronic reconnaissance specialists with a bulbous nose and bomb-bay operator compartments. Other variants included the EB-47E Tell Two for telemetry intelligence gathering work aimed at Soviet ICBM tests, the EB-47L radio relay for SAC's post nuclear attack command structure, RB-47K dual weather/photo-reconnaissance platform, WB-47B/E meteorological aircraft and QB-47 drones. Many were used for test purposes.
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<hi style=hdr1>Extended Missions</hi>
<p>Modified B-47B and the later B-47E models were all fitted for inflight refueling. With Boeing KC-97 and later Boeing KC-135 tanker aircraft utilizing flying booms, the B-47 could fly extended missions. The initial exercise featuring inflight refueling took place in June 1954 when three B-47s of the 22nd Bomb Wing from March AFB, California, flew nonstop to Yokota Air Base, Japan, a distance of 6,700 miles (10,780 km) in less than 15 hours. This flight was made possible by two inflight refuelings from KC-97s. It also marked the first appearance of the B-47 in the Far East.
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<p>One very exceptional record flight for the B-47 took place on 17 November 1954. Colonel David A. Burchinal, commander of the 43rd Bomb Wing, took off from Sidi Slimane in French Morocco en route to RAF Fairford in England. Upon arrival at Fairford he was unable to land as a result of bad weather, so he returned to Sidi Slimane. Upon arrival there he again found the weather too bad for landing. With the assistance of nine aerial refuelings Burchinal kept flying until he was finally able to land at Fairford after a total of 21,163 miles (34,058 km) in 47 hours 35 minutes!
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<p>A very interesting maneuver used with some of the early B-47s was the LABS method of delivery of an atomic weapon. Through extensive modification the B-47 wing was beefed up for low-level operations, for it was proposed that the bomber would come in at tree-top level, zoom upwards, release its bomb while in a vertical climb, continue up into a half-loop and complete the Immelmann maneuver with a half-roll off the top. This would give the B-47 time to make its getaway before the bomb detonated.
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<p>Another feature brought about by the nuclear capability of the aircraft was its all-white paint on the lower surfaces of the aircraft. This coating was applied to reflect the heat and light of a nuclear bomb, giving the structural framework of the B-47 a bit of protection.
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<p>The B-47 also served as a pioneer in the testing and operational deployment of deceleration and braking parachutes. To assist in braking the aircraft a 32-ft (9.75-m) diameter parachute or 'drag chute' was stowed in the bottom of the fuselage forward of the tail guns for release while the aircraft was a few feet in the air before touchdown on the runway. The 'ribbon' parachute was a 16-ft (4.88-m) parachute which could be streamed on the downwind leg of landing to act as an air brake. If a 'go around' was necessary this parachute could be released and sufficient jet thrust would be immediately available for the power required for a second landing approach.
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<p>Two B-47s became testbeds in a very interesting 1955 experiment when two B-47Bs were converted to XB-47Ds. The four inboard engines were removed and replaced with Wright YT49-W-1 turboprop engines, which each provided 9,710 shp (7,240 ekW). The engines were fitted with four-bladed Curtiss turbo-electric propellers with paddle-type blades. At the time these were the most powerful propeller engines to fly outside the USSR.
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<p>Another record-breaking flight was made by a B-47 on 14 August 1957, when a bomber from the 321st Bomb Wing under the command of Brigadier General James V. Edmundson made a nonstop flight from Andersen AFB, Guam, to Sidi Slimane Air Base, Morocco, a distance of 11,450 miles (18,425 km). The flight was made possible by four refuelings from KC-97 tankers.
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<hi style=hdr1>International Incident</hi>
<p>An RB-47H of the 55th Strategic Reconnaissance Wing from Forbes AFB, Kansas, was headlined in international circles when it was shot down by a Soviet MiG fighter on 1 July 1960. Two of its crew were imprisoned by the USSR and four were listed as missing. The USSR claimed that the aircraft was on a spy mission over the Bering Sea, while US officials claimed that the Soviets drew the aircraft off course and shot it down. The two imprisoned fliers were finally released seven months later. One crewman's body was returned but the other three were still listed as missing until a date of declaration of death was set.
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<p>The last B-47 bomber was retired from SAC on 11 February 1966, but it was 29 December 1967 before the last RB-47 was retired from the 55th Strategic Reconnaissance Wing at Forbes AFB, Kansas. Military Airlift Command continued to operate a weather reconnaissance WB-47 until 1969.
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<p>In addition to its primary function as bomber and reconnaissance aircraft the B-47 served as testbed for many types of jet and conventional engines, carried and tested all sorts of electronic countermeasures equipment and airborne missiles. It was utilized by Military Airlift Command as a weather reconnaissance aircraft and during its later years it served as a target drone for experimental surface-to-air missiles. The RB-47 and ERB-47 were instrumental in the development of Elint.
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<hi style=hdr1>Specification</hi>
<hi style=hdr2>Boeing—B-47E-II Stratojet</hi>
<list style=aflst>
<item><hi format=bold>Type:</hi> strategic medium bomber
<item><hi format=bold>Powerplant:</hi> six General Electric J47-GE-25 or -25A turbojets, each developing 7,200-lb (32.03-kN) thrust with water injection
<item><hi format=bold>Performance:</hi> maximum speed 606 mph (975 km/h) at 16,300 ft (4,970 m); cruising speed 557 mph (896 km/h) at 38,500 ft (11,735 m); service ceiling 40,500 ft (12,345 m); range 4,000 miles (6,437 km)
<item><hi format=bold>Weights:</hi> empty 80,756 Ib (36,630 kg); maximum take-off 198,180 lb (89,893 kg)
<item><hi format=bold>Dimensions:</hi> span 116 ft 0 in (35.36 m); length 109 ft 10 in (33.48 m); height 27 ft 11 in (8.51 m); wing area 1,428.0 sq ft (132.66 m<su>2</su>)
<item><hi format=bold>Armament:</hi> two 20-mm cannon in remotely controlled tail turret, plus up to 20,000 lb (9,072 kg) of bombs carried internally
