B-52 Stratofortress | |
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A B-52H from Barksdale AFB flying over the desert | |
Role | Strategic bomber |
Manufacturer | Boeing |
First flight | 15 April 1952 |
Introduction | February 1955 |
Status | Active: 68[1] Reserve: 9[1] |
Primary users | United States Air Force NASA |
Produced | 1952–1962 |
Number built | 744[2] |
Unit cost | B-52B: US$14.43 million[3] B-52H: $9.28 million (1962) B-52H: $53.4 million (1998)[4] |
The Boeing B-52 Stratofortress is a long-range, subsonic, jet-powered strategic bomber designed and built by Boeing and operated by the United States Air Force (USAF).
Beginning with the successful contract bid on 5 June 1946, the B-52 design evolved from a straight-wing aircraft powered by six turboprop engines to the final prototype YB-52 with eight turbojet engines. The aircraft first flew on 15 April 1952 with "Tex" Johnston as pilot.[5] Built to carry nuclear weapons for Cold War-era deterrence missions, the B-52 Stratofortress replaced the Convair B-36. Although a veteran of a number of wars, the Stratofortress has dropped only conventional munitions in combat. The B-52 carries up to 70,000 pounds (32,000 kg) of weapons.[6] Its Stratofortress name is rarely used outside of official contexts; it has been referred to by Air Force personnel as the BUFF (Big Ugly Fat Fucker/Fellow).
The B-52 has been in active service with the USAF since 1955. The bombers flew under the Strategic Air Command (SAC) until it was disestablished in 1992 and its aircraft absorbed into the Air Combat Command (ACC). This remained the case until February 2010 when it became part of Air Force Global Strike Command (AFGSC). Superior performance at high subsonic speeds and relatively low operating costs have kept the B-52 in service despite the advent of later aircraft, including the Mach-3 North American XB-70 Valkyrie, the supersonic Rockwell B-1B Lancer, and the Northrop Grumman B-2 Spirit. 2005 marked the B-52's 50th anniversary of continuous service with its original primary operator.(Others in this class are the English Electric Canberra, the Tupolev Tu-95, the Lockheed C-130 Hercules, the Boeing KC-135 Stratotanker, and the Lockheed U-2.)[7][8][9][10]
Contents |
On 23 November 1945, Air Materiel Command (AMC) issued desired performance characteristics for a new strategic bomber "capable of carrying out the strategic mission without dependence upon advanced and intermediate bases controlled by other countries".[12] The aircraft was to have a crew of five or more turret gunners, and a six-man relief crew. It was required to cruise at 300 mph (240 knots, 480 km/h) at 34,000 feet (10,400 m) with a combat radius of 5,000 miles (4,300 nautical mile, 8,000 km). The armament was to consist of an unspecified number of 20 mm cannon and 10,000 pounds (4,500 kg) of bombs.[13] On 13 February 1946, the Air Force issued bid invitations for these specifications, with Boeing, Consolidated Aircraft, and Glenn L. Martin Company submitting proposals.[13]
On 5 June 1946, Boeing's Model 462, a straight-wing aircraft powered by six Wright T35 turboprops with a gross weight of 360,000 pounds (160,000 kg) and combat radius of 3,110 miles (2,700 nmi, 5,010 km), was declared the winner.[14] On 28 June 1946, Boeing was issued a letter of contract for US$1.7 million to build a full-scale mock-up of the new XB-52 and do preliminary engineering and testing.[15] However, by October 1946, the Air Force began to express concern about the sheer size of the new aircraft and its inability to meet the specified design requirements.[16] In response, Boeing produced Model 464, a smaller four-engine version with a 230,000 pound (105,000 kg) gross weight, which was briefly deemed acceptable.[16][17]
Subsequently, in November 1946, the Deputy Chief of Air Staff for Research and Development, General Curtis LeMay, expressed the desire for a cruise speed of 400 miles per hour (345 kn, 645 km/h), to which Boeing responded with a 300,000 pound (140,000 kg) aircraft.[18] In December 1946, Boeing was asked to change their design to a four-engine bomber with a top speed of 400 miles per hour, range of 12,000 miles (10,000 nmi, 19,000 km), and the ability to carry a nuclear weapon; in total, the aircraft could weigh up to 480,000 pounds (220,000 kg).[19] Boeing responded with two models powered by the T-35 turboprops. The Model 464-16 was a "nuclear only" bomber with a 10,000 pound (4,500 kg) payload, while the Model 464-17 was a general purpose bomber with a 90,000 pound (40,000 kg) payload.[19] Due to the cost associated with purchasing two specialized aircraft, the Air Force selected Model 464-17 with the understanding that it could be adapted for nuclear strikes.[20]
In June 1947, the military requirements were updated and the Model 464-17 met all of them except for the range.[21] It was becoming obvious to the Air Force that, even with the updated performance, the XB-52 would be obsolete by the time it entered production and would offer little improvement over the Convair B-36; as a result, the entire project was put on hold for six months.[22] During this time, Boeing continued to perfect the design which resulted in the Model 464-29 with a top speed of 455 miles per hour (395 kn, 730 km/h) and a 5,000-mile range.[23] In September 1947, the Heavy Bombardment Committee was convened to ascertain performance requirements for a nuclear bomber. Formalized on 8 December 1947, these requirements called for a top speed of 500 miles per hour (440 kn, 800 km/h) and an 8,000 mile (7,000 nmi, 13,000 km) range, far beyond the capabilities of 464–29.[22][24]
The outright cancellation of the Boeing contract on 11 December 1947 was staved off by a plea from its president William McPherson Allen to the Secretary of the Air Force Stuart Symington,[25] reasoning the aircraft design was fully capable of being adapted to new aviation technology and more stringent requirements.[26] In January 1948 Boeing was instructed to thoroughly explore recent technological innovations, including aerial refueling and the flying wing.[27] Noting stability and control problems Northrop was experiencing with their YB-35 and YB-49 flying wing bombers, Boeing insisted on a conventional aircraft, and in April 1948 presented a US$30 million (1948 dollars) proposal for design, construction, and testing of two Model 464-35 prototypes.[28] The Model 464-35 design bore similarity to a later Tupolev design that was built for the Soviet Union, the Tupolev Tu-95 Bear strategic bomber.[29] Further revisions of specifications during 1948 resulted in an aircraft with a top speed of 513 miles per hour (445 kn, 825 km/h) at 35,000 feet (10,700 m), a range of 6,909 miles (6,005 nmi, 11,125 km), and a 280,000 pounds (125,000 kg) gross weight which included 10,000 pounds (4,500 kg) of bombs and 19,875 US gallons (75,225 L) of fuel.[30][31]
In May 1948, AMC asked Boeing to incorporate the previously discarded, but now more fuel-efficient, jet engine into the design.[32] This resulted in Boeing developing yet another revision – in July 1948, Model 464-40 substituted Westinghouse J40 turbojets for the turboprops.[33] Nevertheless, on 21 October 1948, Boeing was told to create an entirely new aircraft using Pratt & Whitney J57 turbojets.[34]
On 25 October, Boeing engineers produced a proposal and a hand-carved model of 464–49.[35][36] The new design built upon the basic layout of the B-47 Stratojet with 35° swept wings, eight engines paired in four underwing pods, and bicycle landing gear with wingtip outrigger wheels.[37] A notable feature of the landing gear was the ability to pivot the main landing gear up to 20° from the aircraft centerline to increase safety during crosswind landings.[38] The aircraft was projected to exceed all design specifications.[39] Although the full-size mock-up inspection in April 1949 was generally favorable, range again became a concern since the J40s and early model J57s had excessive fuel consumption.[40]
Despite talk of another revision of specifications or even a full design competition among aircraft manufacturers, General LeMay, now in charge of Strategic Air Command, insisted that performance should not be compromised due to delays in engine development.[41][42] In a final attempt to increase range, Boeing created the larger 464-67, stating that once in production, the range could be further increased in subsequent modifications.[43] Following several direct interventions by LeMay,[44] Boeing was awarded a production contract for 13 B-52As and 17 detachable reconnaissance pods on 14 February 1951.[45] The last major design change, also at the insistence of General LeMay, was a switch from the B-47 style tandem seating to a more conventional side-by-side cockpit which increased the effectiveness of the copilot and reduced crew fatigue.[46] Both XB-52 prototypes featured the original tandem seating arrangement with a framed bubble-type canopy.[47]
The YB-52, the second XB-52 modified with more operational equipment, first flew on 15 April 1952,[48][Notes 1] A 2 hour, 21-minute proving flight from Boeing Field, King County, near Renton, Washington to Larson AFB was undertaken with Boeing test pilot Alvin M. Johnston and Air Force Lieutenant Colonel Guy M. Townsend.[49] The XB-52 followed on 2 October 1952.[50] The thorough development,[51] including 670 days in the wind tunnel and 130 days of aerodynamic and aeroelastic testing, paid off with smooth flight testing. Encouraged, the Air Force increased its order to 282 B-52s.[52]
Only three of the 13 B-52As ordered were built.[53] All were returned to Boeing, and used in their test program.[54] On 9 June 1952, the February 1951 contract was updated to order the aircraft under new specifications. The final 10, the first aircraft to enter active service, were completed as B-52Bs.[54] At the roll out ceremony on 18 March 1954, Air Force Chief of Staff General Nathan Twining said:
“ | The long rifle was the great weapon of its day. ...today this B-52 is the long rifle of the air age.[55][56] | ” |
The B-52B was followed by progressively improved bomber and reconnaissance variants, culminating in the B-52G and B-52H. In order to allow rapid delivery, production lines were set up both at its main Seattle factory and at Boeing's Wichita facilty. More than 5,000 companies were involved in the massive production effort, with 41% of the airframe being built by subcontractors.[57] The prototypes and all B-52A, B and C models (90 aircraft)[58] were built at Seattle. Testing of aircraft built at Seattle caused problems due to jet noise, with curfews being established for testing of engines, and aircraft being ferried on their maiden flights to Larson Air Force Base, 150 miles (241 km) away, where they were fully tested.[59] As production of the B-47 came to an end, the Wichita factory was phased in for B-52D production, with Seattle building 101 Ds and Wichita 62.[60] Both plants continued to build the B-52E, with 42 built at Seattle and 58 at Wichita,[61] and the B-52F (44 from Seattle and 45 from Wichita.[62] For the B-52G, it was decided in 1957 to transfer all production to Wichita, freeing up Seattle for other tasks (in particular the production of airliners).[63][64] Production ended in 1962 after 744 aircraft were built.[65]
In November 1959, SAC initiated the Big Four modification program (also known as Modification 1000) for all operational B-52s except early B models, intended to improve the aircraft's combat capabilties in the changing strategic environment.[66][67] The program was completed by 1963.[68] The four modifications were:
The ability to carry up to 20 AGM-69 SRAM nuclear missiles was added to G and H models starting in 1971.[69] Fuel leaks due to deteriorating Marman clamps continued to plague all variants of the B-52. To this end, the aircraft were subjected to Blue Band (1957), Hard Shell (1958), and finally QuickClip (1958) programs. The latter fitted safety straps which prevented catastrophic loss of fuel in case of clamp failure.[70]
Ongoing problems with advanced avionics were addressed in the Jolly Well program, completed in 1964, which improved components of the AN/ASQ-38 bombing navigational computer and the terrain computer. The MADREC (Malfunction Detection and Recording) upgrade fitted to most aircraft by 1965 could detect failures in avionics and weapons computer systems, and was essential in monitoring the Hound Dog missiles. The electronic countermeasures capability of the B-52 was expanded with Rivet Rambler (1971) and Rivet Ace (1973).[71] The navigational capabilities of the B-52 were later augmented with the addition of GPS.[72]
To improve safe day and night operations at low altitude, the AN/ASQ-151 Electro-Optical Viewing System (EVS), consisting of a Low Light Level Television (LLLTV) and a Forward Looking Infra-Red (FLIR) system mounted in blisters under the noses of B-52Gs and Hs between 1972 and 1976.[73] To further improve the B-52's offensive ability, Air Launched Cruise Missiles (ALCMs) were fitted.[74] After testing of both the Air Force-backed Boeing AGM-86 and the Navy-backed General Dynamics AGM-109 Tomahawk, the AGM-86B was selected for operation by the B-52 (and ultimately by the B-1 Lancer).[75] A total of 194 B-52Gs and Hs were modified to carry AGM-86s, carrying 12 missiles on underwing pylons, with 82 B-52Hs further modified to carry another eight missiles on a rotary launcher fitted in the aircraft's bomb-bay. To conform with the requirements of the SALT II Treaty for cruise missile capable aircraft to be readily identified by reconnaissance satellites, the cruise missile armed B-52Gs were modified with a distinctive wing root fairing. As all B-52Hs were assumed to be modified, no visual modification of these aircraft was required.[76] In 1990, the stealthy AGM-129 ACM cruise missile entered service. Although originally intended to replace the AGM-86, its high cost and the end of the Cold War stopped production after only 450 were made. Unlike the AGM-86, no conventional (that is, non-nuclear) armed version was built.[77] The B-52 was to have been modified to utilize Northrop Grumman's AGM-137 weapon; however, the missile was canceled due to development costs.[78]
Structural fatigue, exacerbated by the change to low-altitude missions,[80] was first dealt with in the early 1960s by the three-phase High Stress program which enrolled aircraft at 2,000 flying hours.[66][81] This was followed by a 2,000-hour service life extension to select airframes in 1966–1968, and the extensive Pacer Plank reskinning completed in 1977.[82][64] The wet wing introduced on G and H models was even more susceptible to fatigue due to experiencing 60% more stress during flight than the old wing. The wings were modified by 1964 under ECP 1050.[83] This was followed by a fuselage skin and longeron replacement (ECP 1185) in 1966, and the B-52 Stability Augmentation and Flight Control program (ECP 1195) in 1967.[83]
For a study for the U.S. Air Force in the mid-1970s, Boeing investigated replacing the engines, changing to a new wing, and other improvements to upgrade B-52G/H aircraft as an alternative to the B-1A, then in development.[84] Boeing later suggested re-engining the B-52H fleet with the Rolls-Royce RB211 534E-4.[85] This would involve replacing the eight Pratt & Whitney TF33s (total thrust 8 × 17,000 lb) with four RB211s (total thrust 4 × 37,400 lb). The RR engines will increase the range and payload of the fleet and reduce fuel consumption. However, the procurement would cost approximately US$2.56 billion for the whole fleet (US$36 million × 71 aircraft). A Government Accountability Office study concluded that Boeing's estimated savings of US$4.7 billion would not be realized and that it would cost US$1.3 billion over keeping the existing engines. The higher cost was blamed on significant up-front procurement expenditure, necessary re-tooling, and the RB211's higher maintenance cost. The GAO report was subsequently disputed in a Defense Sciences Board report in 2003[86] and revised in 2004 that identified numerous errors in the prior evaluation of the Boeing proposal, and urged the Air Force to re-engine the aircraft without delay. Further, the DSB report stated the program would save substantial funds, reduce greenhouse gas emissions, and increase aircraft range and endurance. This finding was in line with the results of a Congressionally funded US$3M program office study conducted in 2003.[87] The re-engining has not been approved as of 2010.
In 2007 the LITENING targeting pod was fitted, increasing the combat effectiveness of the aircraft during day, night and poor weather conditions in the attack of ground targets with a variety of standoff weapons, using laser guidance under the guidance, a high resolution forward-looking infrared sensor (FLIR) and a CCD camera used to obtain target imagery.[88] LITENING pods have been fitted to a wide variety of other US aircraft, such as the McDonnell Douglas F/A-18 Hornet, the General Dynamics F-16 Fighting Falcon and the McDonnell Douglas AV-8B Harrier II.[89]
In September 2006, the B-52 became one of the first US military aircraft to fly using alternative fuel. It took off from Edwards Air Force Base with a 50/50 blend of Fischer-Tropsch process (FT) synthetic fuel and conventional JP-8 jet fuel which was burned in two of the eight engines.[90] On 15 December 2006 a B-52, tail number 61-0034 Checkmate, took off from Edwards with the synthetic fuel powering all eight engines, the first time an Air Force aircraft was entirely powered by the blend. The seven hour flight was considered a success.[90]
This program is part of the Department of Defense Assured Fuel Initiative, a Pentagon-led aim to reduce the usage of crude oil from foreign producers and obtain half of its aviation fuel from alternative sources by 2016.[90] On 8 August 2007, Air Force Secretary Michael Wynne certified the B-52H as fully approved to use the FT blend.[91] With the success upon the B-52, the Air Force intends to test and certify every airframe in its inventory to use the fuel by 2011.[91]
X/YB-52 | B-52A | B-52B | B-52C | B-52D | B-52E | B-52F | B-52G | B-52H | |
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Unit R&D cost | 100 million (1955) 820 million (current) |
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Airframe | 26,433,518 | 11,328,398 | 5,359,017 | 4,654,494 | 3,700,750 | 3,772,247 | 5,351,819 | 6,076,157 | |
Engines | 2,848,120 | 2,547,472 | 1,513,220 | 1,291,415 | 1,256,516 | 1,787,191 | 1,427,611 | 1,640,373 | |
Electronics | 50,761 | 61,198 | 71,397 | 68,613 | 54,933 | 60,111 | 66,374 | 61,020 | |
Armament | 47,874 | 482,284 | 293,346 | 548,353 | 931,665 | 862,839 | 840,000 | 1,501,422 | |
Ordnance | 9,193 | 11,520 | 10,983 | 17,928 | 4,626 | 3,016 | 6,809 | 6,804 | |
Flyaway cost | 28.38 million (1955) 232.8 M (current) |
14.43 M (1955) 118.4 M (current) |
7.24 M (1955) 59.4 M (current) |
6.58 M (1955) 54 M (current) |
5.94 M (1955) 48.7 M (current) |
6.48 M (1955) 54 M (current) |
7.69 M (1955) 63.1 M (current) |
9.29 M (1955) 76.2 M (current) |
|
Maintenance cost per flying hour | 925 | 1,025 | 1,025 | 1,182 |
Note: The original costs were in approximate 1955 United States dollars.[92] Figures in tables noted with current have been adjusted for inflation.
Although the B-52A was the first production variant, these aircraft were used only in testing. The first operational version was the B-52B that had been developed in parallel with the prototypes since 1951. First flying in December 1954, B-52B, AF Serial Number 52-8711, entered operational service with 93rd Heavy Bombardment Wing (93rd BW) at Castle Air Force Base, California, on 29 June 1955. The wing became operational on 12 March 1956. The training for B-52 crews consisted of five weeks of ground school and four weeks of flying, accumulating 35 to 50 hours in the air. The new B-52Bs replaced operational B-36s on a one-to-one basis.[93]
Early operations were problematic;[94] in addition to supply problems, technical issues also struck.[95] Ramps and taxiways deteriorated under the weight of the aircraft, while the fuel system was prone to leaks and icing,[96] and bombing and fire control computers were unreliable.[95] The two-story cockpit presented a unique climate control problem – the pilots' cockpit was heated by sunlight while the observer and the navigator on the bottom deck sat on the ice-cold floor. Thus, comfortable temperature setting for the pilots caused the other crew members to freeze, while comfortable temperature for the bottom crew caused the pilots to overheat.[97] The J57 engines were still new and unreliable. Alternator failure caused the first fatal B-52 crash in February 1956,[98] which resulted in a brief grounding of the fleet. In July, fuel and hydraulic system problems again grounded the B-52s. To avoid maintenance problems, the Air Force set up Sky Speed teams of 50 maintenance contractors at each B-52 base. In addition to maintenance, the teams performed routine checkups which took one week per aircraft.[99]
On 21 May 1956, a B-52B (52-0013) dropped its first live hydrogen bomb (a Mk-15) over the Bikini Atoll.[100] From 24 to 25 November 1956, four B-52Bs of the 93rd BW and four B-52Cs of the 42nd BW flew nonstop around the perimeter of North America in Operation Quick Kick, covering 15,530 miles (13,500 nm, 25,000 km) in 31 hours 30 minutes. SAC noted that the flight time could have been reduced by 5 to 6 hours if the four inflight refuellings were done by fast jet-powered tanker aircraft rather than propeller-driven KC-97 Stratotankers.[101] In a demonstration of the B-52's global reach, from 16 to 18 January 1957, three B-52Bs made a nonstop flight around the world during Operation Power Flite, covering 24,325 miles (21,145 nm, 39,165 km) in 45 hours 19 minutes (536.8 smph) with several in-flight refuelings by KC-97s.[102] The 93rd Bomb Wing received the Mackay Trophy for their accomplishment.[100]
The B-52 set many records over the next few years. On 26 September 1958, a B-52D set a world speed record of 560.705 miles per hour (487 kn, 902 km/h) over a 10,000 kilometers (5,400 nm, 6,210 mi) closed circuit without a payload. The same day, another B-52D established a world speed record of 597.675 miles per hour (519 kn, 962 km/h) over a 5,000 kilometer (2,700 nmi, 3,105 mi) closed circuit without a payload.[82] On 14 December 1960, a B-52G set a world distance record by flying unrefueled for 10,078.84 miles (8,762 nm, 16,227 km); the flight lasted 19 hours 44 minutes (510.75 mph).[103] From 10 to 11 January 1962, a B-52H set a world distance record by flying unrefueled, surpassing the prior B-52 record set two years earlier, from Kadena Air Base, Okinawa, Japan, to Torrejon Air Base, Spain, covering 12,532.28 miles (10,895 nmi, 20,177 km).[104]
Originally there were concerns about the lifespan of the fleet. Several projects beyond the B-52, the Convair B-58 Hustler and North American XB-70 Valkyrie, had either been aborted or proved disappointing in light of changing requirements, leaving the older B-52 as the main bomber as opposed to the planned successive aircraft models.[105][106] On 19 February 1965 General Curtis E. LeMay testified to Congress that the lack of a followup bomber project to the B-52 raised the danger that:
“ | The B-52 is going to fall apart on us before we can get a replacement for it.[107] | ” |
When the B-52 entered into service, the Strategic Air Command (SAC) intended for it to be used to deter against and counteract the vast and modernising Soviet military. As the Soviet Union increased their nuclear capabilities, destroying or 'countering' the forces that would deliver nuclear strikes (bombers, missiles, etc.) became of great strategic importance.[108] The Eisenhower administration endorsed this switch in focus, the President in 1954 expressing a preference for military targets over those of civilian ones, a principle reinforced in the Single Integrated Operation Plan (SIOP), an plan of action in the case of nuclear war breaking out.[109]
Throughout the Cold War, B-52s performed airborne alert patrols under code names such as Head Start, Chrome Dome, Hard Head, Round Robin, and Giant Lance. Bombers loitered at high altitude near points outside the Soviet Union to provide rapid first strike or retaliation capability in case of nuclear war.[110] This was apart of the role of deterrence to the Sovier Union via the concept of Mutually Assured Destruction.[111]
Due to the late 1950s era threat of surface-to-air missiles (SAMs) that could threaten high-altitude aircraft,[112][113] seen in practice in the 1960 U-2 incident,[114] the intended use of B-52 was changed to serve as a low-level penetration bomber during a foreseen attack upon the Soviet Union, as terrain masking provided an effective method of avoiding radar and thus the threat of the SAMs.[67]
Although never intended for the low-level role, the B-52's flexibility allowed it to outlast several intended successors as the nature of the air warfare environment changed. The B-52's large airframe with internal room allowed the addition of improved electronic countermeasures suites and other adaptions to be made over time.[115] Other aircraft, such as the General Dynamics F-111 Aardvark, complimented the B-52 in roles that the aircraft was not as capable in, such as missions involving high-speed low-level penetration dashes.[116]
The B-52's official name Stratofortress has been rarely used in informal circumstances; it has become common amongst personnel to refer to the aircraft as the BUFF (Big Ugly Fat Fucker).[117][Notes 2][118]
With the escalating situation in Southeast Asia, 28 B-52Fs were fitted with external racks for 24× 750 pound (340 kg) bombs under project South Bay in June 1964; an additional 46 aircraft received similar modifications under project Sun Bath.[62] In March 1965, the United States commenced Operation Rolling Thunder. The first combat mission, Operation Arc Light, was flown by B-52Fs on 18 June 1965, when 30 bombers of the 9th and 441st Bombardment Squadrons struck a communist stronghold near the Bến Cát District in South Vietnam. The first wave of bombers arrived too early at a designated rendezvous point, and while maneuvering to maintain station, two B-52s collided, resulting in the loss of both bombers and eight crewmen. The remaining bombers, minus one more which turned back due to mechanical problems, continued on towards the target, which was bombed successfully.[119]
Beginning in late 1965, a number of B-52Ds underwent Big Belly modifications to increase bomb capacity for carpet bombings.[120] While the external payload remained at 24× 500 pound (227 kg) or 750 pound (340 kg) bombs, the internal capacity increased from 27 to 84× 500 pound bombs or from 27 to 42× 750 pound bombs.[121] The Big Belly modification created enough capacity for a total of 60,000 pounds (27,215 kg) in 108 bombs. Thus modified, B-52Ds could carry 22,000 pounds (9,980 kg) more than B-52Fs.[122] Replacing B-52Fs, modified B-52Ds entered combat in April 1966 flying from Andersen Air Force Base, Guam. Each bombing mission lasted 10 to 12 hours with an aerial refueling by KC-135 Stratotankers.[48] In spring 1967, the aircraft began flying from U Tapao Airfield in Thailand giving the aircraft the advantage of not requiring in-flight refueling.[121]
On 22 November 1972, a B-52D (55-0110) from U-Tapao was hit by a surface-to-air missile (SAM) while on a raid over Vinh. The crew was forced to abandon the damaged aircraft over Thailand. This was the first B-52 to be destroyed by hostile fire in Vietnam.[123] In total 30 B-52s were lost during the war, including ten B-52s being shot down over North Vietnam with five others being damaged and crashing in Laos or Thailand.[124][125]
The zenith of B-52 attacks in Vietnam was Operation Linebacker II (sometimes referred to as the Christmas Bombing) which consisted of waves of B-52s (mostly D models, but some Gs without jamming equipment and with a smaller bomb load). Over 12 days, B-52s flew 729 sorties,[126] dropping 15,237 tons of bombs on Hanoi, Haiphong, and other targets.[127][128] Originally 42 B-52s were committed to the war; however, numbers were frequently twice this figure.[129] The B-52's usage had been highly important in the war, although their lack of precision weapons translated to limited deployment; American journalist and war correspondent Neil Sheehan described their role in the war:
“ | The B-52s were restricted to bombing suspected Communist bases in relatively uninhabited sections, because their potentcy approached that of a tactical nuclear weapon. A formation of six B-52s, dropping their bombs from 30,000 feet, could "take out"... almost everything within a "box" approximately five-eights mile wide by two miles long. Whenever Ark Light struck... in the vicinity of Saigon, the city woke from the tremor.[130] | ” |
During the Vietnam War, B-52D tail gunners were credited with shooting down two MiG-21 "Fishbeds". On 18 December 1972, tail gunner SSgt Samuel O. Turner's B-52 had just completed a bomb run for Operation Linebacker II and was turning away when a North Vietnamese Air Force MiG-21 approached.[131] The MiG and the B-52 locked onto one another. When the fighter drew within range, Turner fired his quad (four guns on one mounting) .50 caliber machine guns.[132] The MiG exploded aft of the bomber,[131] a victory confirmed by MSG Lewis E. Le Blance, the tail gunner in a nearby Stratofortress. Turner received a Silver Star for his actions.[133] His B-52, tail number 55-0676, is preserved on display at Fairchild AFB in Spokane, Washington.[131]
On 24 December 1972, during the same bombing campaign, the B-52 Diamond Lil was headed to bomb the Thai Nguyen railroad yards when tail gunner A1C Albert E. Moore spotted a fast-approaching MiG-21.[134] Moore opened fire with his quad fifties at 4,000 yards, and kept shooting until the fighter disappeared from his scope. TSG Clarence W. Chute, a tail gunner aboard another Stratofortress, watched the MiG catch fire and fall away. The Diamond Lil is preserved on display at the United States Air Force Academy in Colorado.[134] Moore was the last recorded bomber gunner to shoot down an enemy aircraft with machine guns in aerial combat.[132]
The last Arc Light mission took place on 15 August 1973, as US military action in Vietnam was wound down.[135] These victories make the B-52 the largest aircraft to be credited with air-to-air kills.[136]
B-52Bs reached the end of their structural service life by the mid-1960s and all were retired by June 1966, followed by the last of the B-52Cs on 29 September 1971; except for NASA's B-52B "008" which was eventually retired in 2004 at Edwards AFB, California.[137] Another of the remaining B Models, "005" is on display at the Wings Over the Rockies Air and Space Museum in Denver, Colorado.[138]
A few time-expired E models were retired in 1967 and 1968, but the bulk (82) were retired between May 1969 and March 1970. Most F models were also retired between 1967 and 1973, but 23 survived as trainers until late 1978. The fleet of D models served much longer; eighty D models were extensively overhauled under the Pacer Plank program during the mid-1970s.[139] Skinning on the lower wing and fuselage was replaced, and various structural components were renewed. The fleet of D models stayed largely intact until late 1978, when 37 un-upgraded Ds were retired.[140] The remainder were retired between 1982 and 1983.[141]
The remaining G and H models were used for nuclear standby ("alert") duty as part of the United States' nuclear triad. This triad was the combination of nuclear-armed land-based missiles, submarine-based missiles and manned bombers. The B-1B Lancer, intended to supplant the B-52, replaced only the older models and the supersonic FB-111.[142] In 1991, B-52s ceased continuous 24-hour SAC alert duty.[143]
After the fall of the Soviet Union, the B-52Gs were destroyed per the terms of the Strategic Arms Reduction Treaty (START). The AMARC was tasked with eliminating 365 B-52 bombers, completion of this task was to be verified by Russia via satellite and first-person inspection at the AMARC facility. To place the aircraft permanently beyond restoration, the B-52s were cut up into pieces with a 13,000 pound guillotine.[144]
B-52 strikes were an important part of Operation Desert Storm. Flying about 1,620 sorties, B-52s delivered 40% of the weapons dropped by coalition forces while suffering only one non-combat aircraft loss, with several receiving minor damage from enemy action.[4]
On 16 February 1991, a flight of B-52Gs flew from Barksdale AFB, Louisiana, refueled in the air en route, struck targets in Iraq, and returned home – a journey of 35 hours and 14,000 miles round trip. It set a record for longest-distance combat mission.[146] B-52Gs operating from bases at Jeddah, Saudi Arabia; RAF Fairford in the United Kingdom; Moron AB, Spain; and the island of Diego Garcia flew bombing missions over Iraq, initially at low altitude. After the first three nights, the B-52s moved to high-altitude missions instead, which reduced their effectiveness and psycological impact compared to the low altitude role initially played.[147]
The conventional strikes were carried out by three bombers dropping up to 153 750-pound bombs, covering an area 1.5 miles long by 1 mile wide. The bombings demoralized the defending Iraqi troops, many of whom surrendered in the wake of the strikes.[148] In 1999, the science and technology magazine Popular Mechanics described the B-52's role in the conflict:
“ | The Buff's value was made clear during the Gulf War and Desert Fox. The B-52 turned out the lights in Baghdad.[149] | ” |
From 2 to 3 September 1996, two B-52H struck Baghdad power stations and communications facilities with 13 AGM-86C conventional air-launched cruise missiles (CALCM) as part of Operation Desert Strike, a 34-hour, 16,000-mile round trip mission from Andersen AFB, Guam – the longest distance ever flown for a combat mission.[150]
During the conflict several claims of Iraqi air-to-air successes were made, including an Iraqi pilot, Khudai Hijab, firing a Vympel R-27R missile from his MIG-29 and damaging a B-52G on the opening night of the Gulf War.[151] However, the United States Air Force disputes this claim, stating the bomber was actually hit by friendly fire, a AGM-88 High-speed, Anti-Radiation Missile (HARM) that homed on the fire-control radar of the B-52's tail gun; the jet was subsequently renamed "In HARM's Way".[152] Shortly following this incident, General George Lee Butler announced that the gunner position on B-52 crews was to be eliminated, and the gun turrets permanently deactivated, commencing on 1 October 1991.[153]
Since the mid-1990s, the B-52H has been the only variant remaining in military service;[Notes 3] it is currently stationed at:
The B-52 contributed to Operation Enduring Freedom in 2001 (Afghanistan/Southwest Asia), providing the ability to loiter high above the battlefield and provide Close Air Support (CAS) through the use of precision guided munitions, a mission which previously would have been restricted to fighter and ground attack aircraft.[155] B-52s also played a role in Operation Iraqi Freedom, which commenced on 20 March 2003 (Iraq/Southwest Asia). On the night of 21 March 2003, B-52Hs launched at least one hundred AGM-86C CALCMs at targets within Iraq.[156]
In August 2007, a B-52H ferrying AGM-129 ACM cruise missiles from Minot Air Force Base to Barksdale Air Force Base for dismantling was mistakenly loaded with six missiles from which the nuclear warhead was not removed. The weapons did not leave USAF custody and were secured at Barksdale.[157][158]
As of February 2009[update], 90 of the original 744 B-52 aircraft were still operational within the U.S. Air Force. Four of 18 B-52Hs from Barksdale AFB that are currently being retired are in the "boneyard" of 309th AMARG at Davis-Monthan AFB as of 8 September 2008.[159]
Even while the Air Force works on its Next-Generation Bomber and 2037 Bomber projects, it intends to keep the B-52H in service until at least 2040, nearly 80 years after production ended. This will be an unprecedented length of service for a military aircraft.[4][160] B-52s are periodically refurbished at USAF maintenance depots such as Tinker Air Force Base, Oklahoma.[161]
The USAF continues to rely on the B-52 because it remains an effective and economical heavy bomber, particularly in the type of missions that have been conducted since the end of the Cold War against nations that have limited air defense capabilities. The B-52's capacity to "loiter" for extended periods over (or even well outside) the battlefield, while delivering precision standoff and direct fire munitions, has been a valuable asset in conflicts such as Operation Iraqi Freedom.[162]
The speed of the B-1 Lancer and the stealth of the B-2 Spirit have only been useful until enemy air defenses were destroyed, a task that has been swiftly achieved in recent conflicts. The B-52 boasts the highest mission capable rate of the three types of heavy bombers operated by the USAF. Whereas the B-1 averages a 53% ready rate, and the B-2 achieved 26%, the B-52 averages 80% as of 2001.[145]
Additionally, a proposed variant of the B-52H was the EB-52. This version would have modified and augmented 16 B-52H airframes with additional electronic jamming capabilities.[163][164] This new aircraft would have given the USAF an airborne jamming capability that it has lacked since retiring the EF-111 Raven. The program was canceled in 2005 following removal of funding for the stand-off jammer. The program was revived in 2007 but funding was again cut in early 2009.[165]
Variant | Produced | Entered Service |
---|---|---|
XB-52 | 2 (1 redesignated YB-52) | prototypes |
B-52A | 3 | |
NB-52A | 1 Modified B-52A | |
B-52B | 50 | 29 June 1955 |
RB-52B | 27 Modified B-52Bs | |
NB-52B | 1 Modified B-52B | |
B-52C | 35 | June 1956 |
B-52D | 170 | December 1956 |
B-52E | 100 | December 1957 |
B-52F | 89 | June 1958 |
B-52G | 193 | 13 February 1959 |
B-52H | 102 | 9 May 1961 |
Grand total | 744 production |
The B-52 went through several design changes and variants over its 10 years of production.[92]
There are many B-52s still in use and others on static display at USAF bases and museums around the world.
Data from Knaack,[193] USAF fact sheet,[6] Quest for Performance[194]
General characteristics
Performance
Armament
Avionics
The B-52 has been featured in a number of major films, most notably: Bombers B-52 (1957),[196] A Gathering of Eagles (1963),[197] Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964),[198] and By Dawn's Early Light (1990).[199] It has also been featured in numerous novels, such as most of the early Patrick McLanahan novels by Dale Brown, which feature one or more heavily modified B-52 bombers, nicknamed the "EB-52 Megafortress".[200] A 1960s hairstyle, the beehive, is also called a B-52 for its resemblance to the aircraft's distinct nose.[201] The popular band The B-52's was subsequently named after this hairstyle.[201]
Related development
Comparable aircraft
Related lists
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