The B-52G (Model 464-253) was the most numerous sub-type of the Stratofortress series, a total of 193 being built between October 1958 and February 1961. It was the first Stratofortess version to be built exclusively at the Wichita factory.
The B-52G design was officially begun in June of 1956. At that time, the Convair B-58 Hustler program seemed to be in trouble, and the development of the B-52G was initiated as a safety measure intended to prevent possible technical obsolescence of the strategic bomber force in the 1960s. As it turned out, the service of the B-52G far outlasted that of the B-58.
Thee were three separate orders for the B-52G:
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AF33(600)-35992 finalized on May 15, 1958, covering 53 aircraft
obtained with FY 57 funds with serials 57-6468/6520.
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AF33(600)-36470 finalized May 15, 1958 covered 101 examples
obtained with FY 58 funds. Serials were 58-158/258.
- AF33(600) finalized April 28, 1959 calling for 39 aircraft obtained with FY 59 funds. Serials were 59-2564/2602.
In the design of the B-52G, considerable attention was paid to reducing the structural weight. Different materials were used in the construction of the airframe, and the wing structure was extensively redesigned. The most visible difference was a vertical tail which was reduced in size. The height was reduced from 48 feet 3 inches to 40 feet 7 inches, and the chord (width) was increased. The new tail was tested on the first B-52A (52-001) and perhaps also on either the XB-52 or YB-52 before being adopted as standard for the B-52G.
The B-52G retained the J57-P-43W engines of the B-52F, but the engine's water injection system was improved in duration capability by adding a 1200-gallon tank of water in the forward fuselage.
In the B-52G, the gunner was moved from the extreme rear of the aircraft to a position beside the electronic warfare officer in the forward part of the fuselage. He was provided with a rearward-facing upward-firing ejector seat. The locations of the other four crew members (pilot, copilot, bombardier and radar navigator) were unchanged.
A new Avco-Crosley AN/ASG-15 fire control system was fitted in the extreme tail to support the now remotely-operated rearward-firing gun turret. Like earlier versions of the fire control system, the AN/ASG-15 featured separate radar dishes for search and track, but it also carried a television camera, although the camera was later replaced by ALQ-117 countermeasures gear. The gunner could operate the tail guns either by using the AGS-15 fire-contol system or by using a remote control system which he monitored approaching threats either by radar or by closed-circuit television.
The ammunition capacity of the tail gun was altered. The removal of the rear gunner's position made it possible to move the stowage location for the braking parachute from below to above the extreme aft fuselage section.
In the design of the B-52G, considerable attention was paid to improvements in crew comfort. In previous B-52s, pilots had often roasted while the bombardier and radar navigator froze, leading to lots of arguments over the cabin temperature control setting. The seats were redesigned to lessen the fatigue of 20-hour missions.
The B-52G retained the AN/ASQ-38 bombing navigation system of the B-52F. However, the nose radome was enlarged, and was now of one-piece construction.
The B-52G featured a "wet" wing which resulted in it being able to carry 48,030 gallons of fuel as opposed to the 41,553 gallons of the B-52F. Each wing had three integral fuel tanks which replaced the rubber bladder-type tanks in the wings of previous versions. This called for a complete structural redesign. The new wing required the machining of long alloy wing skins so that stiffeners were an integral part of the structure. This resulted in a surface with a minimum of chordwise joints which, it was hoped, would reduce the possibility of fuel leaks and fatigue.
The new wing also saved weight by dispensing with the ailerons, relying entirely on the spoilers for lateral control. However, the elimination of the ailerons did have some unpleasant side effects. The missing ailerons, acting in conjunction with the shorter rudder, increased the tendency of the aircraft to Dutch roll, a problem with all large swept wing aircraft. The existing yaw damper was not adequate to correct this problem. The elimination of the ailerons also changed the lateral response--when a turn was initiated the spoilers that were raising up would often induce a slight buffet. The spoilers also induced a slight tendency for the nose to pitch-up when they were extended. This effect was particularly troublesome during aerial refuelling, where the lateral spoiler movement that was needed to keep station often produced a nose pitch-up. This motion was very fatiguing for the pilot to correct, and resulted in a later modification.
The familiar jettisonable 3000-gallon underwing auxiliary fuel tanks of the B-52C through F were replaced by smaller, fixed 700-gallon tanks. These were actually fitted not so much for the additional fuel capacity but more for their role as bob weights to help prevent wing flutter.
In spite of the weight reduction program, the gross weight of the B-52G was up to 488,000 pounds because of the increased fuel capacity. Total internal fuel tankage was 46,575 gallons. With the two external tanks fitted, total fuel capacity was 47,975 gallons. This offered greatly enhanced range performance.
The B-52G flew for the first time on August 31, 1958. The B-52G entered service with the 5th Bomb Wing at Travis AFB on February 13, 1959. In May, the 42nd Wing began to receive B-52Gs.
From the 55th B-52G onward (58-0159), ability to carry the North American GAM-77 (later redesignated AGM-28) Hound Dog air-launched cruise missile was added. An underwing pylon was added inboard of the inner engine pods underneath each wing, one Hound Dog being carried on each pylon. Earlier B-52Gs were upgraded by 1962 with Hound Dog capability, as well as some earlier B-52s. All versions from the B-52C onward are known to have carried the Hound Dog at some time in their careers.
The AGM-28 Hound Dog was 42 feet long with a wingspan of 12 feet. It was powered by by a single Pratt & Whitney J52-P-3 turbojet engine rated at 7500 lb.s.t. It had a maximum speed of Mach 2.1, and maximum range at high altitude was about 700 nautical miles, although this was reduced to 200 nautical miles when at low level. The Hound Dog was guided by an inertial system assisted by an astrotracker. The inertial guidance system was updated by the B-52's onboard system just before launch. Since the inertial guidance system relied on no external signals, it could not be jammed. The flight path could be profiled for tree top level or for altitudes as high as 55,000 feet. The AGM-28 carried a single W28 thermonuclear warhead, with a 1 megaton yield. The J52 jet engines of the AGM-28 could be used for extra power during takeoff, and the inertial navigation system of the AGM-28 could even be used as a backup for the B-52's own system.
The first Hound Dog-equipped B-52G unit was the 4135th Strategic Wing, based at Eglin AFB in Florida. This unit first deployed in December of 1959. At the peak in 1963, the Hound Dog force numbered 600. However, the weapon was not all that accurate, and its primary mission in the case of a nuclear war would probably have been to go ahead of the penetrating bombers to clear a path through enemy defenses. The Hound Dog rapidly became obsolete in the face of technological advances, the weapon being gradually withdrawn from service beginning in 1967. By the end of 1969, the number of missiles was down to 350. By the end of June 1975, the missile was finally taken off alert duty, but it remained on non-operational status for a while longer. The last AGM-28 was scrapped in June 1978, and the only ones left are now on display in museums.
The B-52G could also carry up to four McDonnell GAM-72 (later AGM-20) Quail decoy missiles internally in the extreme rear of the weapons bay. The GAM-72 decoy missile was designed to simulate the radar cross section, infrared signature, and flight profile of the B-52. This was done by careful use of radar reflectors, electronic repeaters, chaff, and infrared simulators. The Quail could be programmed to perform at least one change of cruising speed and two turns. The Quail was 12 feet 10.6 inches long, the wing span was 5 feet 4.5 inches, and the height was 3 feet 3.5 inches when the aerodynamic surfaces were deployed. The Quail was powered by a single General Electric J85-GE-7 turbojet. Maximum speed of the AGM-20 was Mach 0.85 and the range was 460 nautical miles when flying at 50,000 feet. When flying at 35,000 feet, maximum speed was Mach 0.8 and range was 393 nautical miles.
The Quails were carried in a folded configuration inside the weapons bay. At the time of launch, a retractable device lowered the decoys into the slipstream. The flying surfaces were deployed and the engine was started prior to launch on the command of the radar navigator. Any one or all the missiles could be jettisoned in the event of a malfunction, and it was possible to dump the entire package in the case of a major emergency.
Development of the GAM-72 was initiated back in October of 1952, when SAC issued a requirement for a decoy that could be deployed and launched from a bomber prior to penetrating enemy airspace. In February 1956, McDonnell was selected as the prime contractor. Flight trials of the XGAM-72 began in November 1958. A contract for production was awarded to McDonnell on December 31, 1958.
The first Quails began to join the 4135th Strategic Wing at Eglin AFB in late 1960. A total of 14 Stratofortress squadrons eventually received the Quail. The Quail was withdrawn in 1989, when a shortage of spares forced its retirement.
The B-52G had a lighter structure than previous versions in order to save weight, but it carried more fuel. This meant that fatigue problems resulting from the structural flexing generated by the stresses of low-level flying and midair refuelling manifested themselves earlier in the life cycle of the airframe. This was especially the case in the region of the wing structure where most of the weight savings had been achieved by using an aluminum alloy. Fatigue cracks got so bad that stringent flying restriction had to be imposed, pending modifications. In May of 1961, a program was approved in which the wings were modified and strengthened as part of the regular IRAN schedules for the aircraft in the B-52 fleet. The project was finally completed in September of 1964.
In 1970, the Air Force decided to equip the B-52Gs to carry the Boeing AGM-69A short-range attack missile (SRAM). This involved the addition of underwing pylons, launch gear, rotary launchers, and new avionics. These modifications began in October 1971, and the first SRAM-equipped B-52G entered service with the 42nd Bomb Wing in March of 1972. Each modified B-52G could carry up to 20 SRAMs, 12 externally on the underwing pylons and 8 on a rotary launcher inside the rear of the bomb bay. The SRAM was 14 feet long , 17.5 inches in diameter, and weighed about 2300 pounds. It was powered by a Thiokol SR-75-LP-1 restartable solid-fuelled two-pulse rocket motor which gave a maximum speed of Mach 2.5. A General Precision/Kearfott inertial guidance system was fitted. The missile could be flow at either supersonic or subsonic speeds, and could follow either a high-altitude semi-ballistic trajectory or a low-altitude profile. It was designed to attack targets ahead of the launch aircraft or could turn in flight to attack installations to the side or behind the bomber. A 170 kiloton W69 nuclear warhead was carried.
External carriage of the SRAM was abandoned in the the early 1980s. Concerns over the continued safety of the warheads in the SRAM caused the weapon to be removed from the operational inventory in 1990.
During 1967-1969, some of the B-52Gs that had been assigned to conventional warfare missions were given the same set of electronic warfare updates as were assigned to the B-52D fleet. This was done under a program known as Rivet Rambler or Phase V ECM fit. This involved the fitting of one AN/ALR-18 automated set-on receiving set, one AN/ALR-20 panoramic receiver set, one AN/APR-25 radar homing and warning system, four AN/ALT-6B or AN/ALT-22 continuous wave jamming transmitters, two AN/ALT-16 barrage-jamming systems, two AN/ALT-32H and one AN/ALT-32L high- and low-band jamming sets, six AN/ALE-20 flare dispensers (96 flares) and eight AN/ALE-24 chaff dispensers (1125 bundles). Some of the B-52Gs that went through this upgrade program were also provided with AN/ALE-25 forward-firing chaff dispenser rocket pods suspended on pylons between the engine pods. Each pod was about 13 feet long and contained 20 Tracor AN/ADR-8 2.5-inch folding fin chaff rockets that could be fired either manually or automatically by the AN/ASG-21 fire control system.
Between 1972 and 1976, all surviving B-52Gs were provided with the AN/ASQ-151 Electro-optical Viewing System (EVS) to give the B-52 crew enhanced vision when flying at low level at night. The system was contained in two prominent fairings underneath the nose. The port fairing contained a steerable Westinghouse AN/AVQ-22 low-light-level television camera, whereas the starboard unit contained a Hughes AN/AAQ-6 forward-looking infrared (FLIR) sensor. Both units feed information into video display screens for the pilot, copilot, and both navigators. Data that could be presented on these screens included overlaid terrain avoidance profile trace in both TV or FLIR mode, alphanumeric symbology which included a height reading from the radar altimeter and time-to-go before weapons release, as well as indicated airspeed, heading error and bank steering, artificial horizon overlay and attitude and position of the sensor in use. When not in use, the EVS sensors rotated into the blisters for protection. The optical windscreens for the sensors even had inflight washing capability.
The Phase VI ECM Defensive Avionics Systems (ECP2519) was an upgrade program designed to improve the electronic countermeasures capabilities of the B-52G fleet. The program was started in December of 1971, but it took several years of development and testing before the final configuration was decided, and then several more years before the entire fleet could be upgraded. Upgrades were still continuing as recently as the late 1980s. Externally, the most visible change was in the extreme aft fuselage, which was extended farther to the rear by 40 inches to accommodate extra electronic equipment. However, the addition of so many antennae required that many other assorted bumps and warts be added over the exterior, which spoiled the fairly clean lines of the original B-52G. The equipment added as part of Phase VI consisted of an AN/ALR-20A countermeasures receiver, an AN/ALQ-117 active countermeasures set, an AN/ALR-46(V) digital radar warning receiver set, an AN/ALQ-122 false target generator system (sometimes known as Smart Noise Operation Equipment), AN/ALT-28 noise jammers, AN/ALQ-153 tail warning radar set, AN/ALT-32H and AN/ALT-32L high and low-band jamming sets, AN/ALT-16A barrage-jamming system, 12 AN/ALE-20 flare dispensers (192 flares) and eight AN/ALE-24 chaff dispensers (1125 bundles). The chaff dispensers were housed in the wing trailing edge, just outboard of the inner engine pod in the region between the two sets of flaps. This space had been occupied by an aileron on previous versions of the B-52. The AN/ALQ-117 system was supported by a pair of antennae which were housed inside a rather prominent teardrop-shaped bulge that protruded from each side of the nose underneath the cockpit, as well as special antennae installed in the extreme rear of the fuselage. The antenna for the ALT-28 was housed inside a rather prominent bump installed on the forward nose just ahead of the windshield. The antennae for the AN/ALQ-153 tail-warning radar were installed in a pod which was attached to the tip of the port horizontal tail. Subsequent refinements involved replacement of the AN/ALQ-117 unit by an AN/ALQ-172(V)1 unit, but still keeping the antennae associated with the original AN/ALQ-117.
By the mid-1970s, the AN/ASQ-38 bomb/navigation equipment initially fitted to the B-52G was becoming increasingly obsolete and subject to frequent malfunctions. Beginning in 1980, this system was replaced by the AN/ASQ-176 Offensive Avionics System (OAS). Almost all of the analog systems of the AN/ASQ-38 were replaced by solid-state digital electronic systems. The AN/ASQ-176 OAS had a MilStd 1553A digital data bus, and the package had new controls and displays as well as a new AN/APN-224 radar altimeter, two AN/ASN-136 inertial navigation systems, an AN/ASN-134 attitude heading reference system, an AN/APN-218 Doppler radar, an inertial navigation system plus missile interface units and major modifications to the primary attack radar. The system was specially configured for low-altitude use and embodied hardening against electromagnetic pulse effects. It was considerably more reliable than the AN/ASQ-38 that it replaced.
In the early 1980s, 98 B-52Gs were modified to carry the Boeing AGM-86B Air-Launched Cruise Missile (ALCM). The ALCM is powered by a 600 lb.s.t. Williams F107-WR-100 turbofan, which is fed by an inlet which folds out on the top of the missile. It is 20 feet 9 inches long. The ALCM is carried with the engine air intake, the wings, the elevons and the vertical tail surfaces all folded up into the body of the missile. When released from the B-52G, these surfaces deploy and the engine starts. When fully extended, the wings have a span of 12 feet and are swept at 25 degrees. Of the three tail surfaces, only the two horizontal surface provide control during flight. The ALCM is equipped with a single W80-1 nuclear warhead with a selectable yield in the 150-170 kiloton range. Guidance is by a combination of inertial guidance and terrain contour matching. Once the B-52G is airborne, the aircraft's INS and altimeter systems continuously provide precise positional data to the missile's INS. Prior to launch, the missile computer onboard the B-52G downloads target location along with a set of a set of pre-gathered mapping data into the onboard memory of the missile. The AGM-86B missile thus has a precise position plot at the time of launch, and uses terrain contour matching and a radar altimeter to survey the surrounding terrain as the missile flys over it at low level, comparing selected points along the way with those on the electronic map stored in the onboard computer. The missile can can fly at very low levels and can skim over mountains or down valleys in order to avoid detection. Maximum range of the AGM-86B is about 1500 miles and gross weight is 3200 pounds. The B-52G could carry six AGM-86Bs on each of the two underwing pylons.
Development of the AGM-86 cruise missile began back in the late 1960s, with the first flight taking place in 1976. The original AGM-86A version of the ALCM had been developed for the Rockwell B-1A Rockwell B-1A bomber, and the length of the missile had been constrained by the requirement that it be albe to fit inside the B-1A's weapons bay. When the B-1A was cancelled, the ALCM design was reworked for the B-52G, resulting in the AGM-86B version with a longer fuselage. The first AGM-86B became operational in 1982, and production ended in October of 1986. A total of 1715 ALCMs were built.
Under the provisions of the SALT II treaty, aircraft carrying cruise missiles must be readily identifiable as such by reconnaissance satellites, so the AGM-86B-equipped B-52G was provided with non-functional wing root fairings known as "strakelets". The modification had to be visible from above so that spy satellites could confirm the number of cruise missile-capable aircraft, and it had to be made aerodynamically and structurally integral with the aircraft so that the change could not be quickly altered or moved from one aircraft to another.
The AGM-86C is a modified version of the AGM-86B with a 992-pound high-explosive blast-fragmentation warhead in place of the nuclear warhead and a GPS navigation system replacing the terrain-following inertial navigation system. Since the high-explosive warhead is heavier than the nuclear warhead it replaced, the maximum range of the C-version is only 1200 miles. The AGM-86C entered service with the B-52G fleet in the late 1980s, but its existence was kept secret until 1992, when it was revealed that 35 of these weapons had been used against targets in Iraq during the Gulf War. Its classified codename was Senior Surprise. Most of the AGM-86Cs were expended during the Gulf War, but more were modified later. Since the end of the Cold War has all but eliminated the need for the nuclear mission, the Air Force has proposed that 200 or 300 more AGM-86Bs be converted to AGM-86C configuration.
Some sources indicate that there exist other modified versions of the AGM-86B that are equipped as decoys or fitted with carbon-fiber dispensers (like those use by the BGM-109s during the Gulf War) or which are capable of carrying electro-magnetic pulse (EMP) warheads which would generate a burst of microwave energy to disable enemy electronic communications systems.
By the end of 1988, 30 years of attrition had reduced the original fleet of 193 B-52Gs to 166. 98 of them had been converted to operate the AGM-86B ALCM. Units operating the ALCM included the 97th BW, the 379th BW, and the 416th BW, plus the 2nd BW's 596th BS. Some ALCM-configured B-52Gs were used for crew training tasks by the 93rd BW.
Non-ALCM B-52Gs featured a much shorter "stub" underwing pylon. This
pylon was compatible with the original I-beam arrangement as well as
with the newer Heavy Stores Adapter Beam (HSAB). When used in concert
with the I-beam, external payload capacity was identical to that of
aircraft retaining the AGM-28 pylon. When employed with the HSAB,
however, only nine M117 bombs (or similar weapons) could be carried on
each pylon. However, the HSAB permitted much heavier ordnance items
to be carried externally such as five 2000-lb Mk84 bombs or Mk60
mines; six Mk55 or Mk56 mines, or six AGM-84 Harpoon antiship
missiles. Alternatively, they can carry up to four AGM-142A Raptor
3000-lb stand-off attack missiles.
The AGM-142A Raptor is a joint effort on the part of Israel's Rafael
and the US's Lockheed Martin. It is a derivative of the Rafael Popeye
missile that has been in service in Israel. The US version was
developed under a program code-named Have Nap. It is a
precision-guided air-to-ground missile that is designed to be
effective against high-value ground and sea targets such as
powerplants, missile sites, bridges, ships, and bunkers. The Raptor
employs mid-course autonomous guidance based on inertial navigation,
then homes in on its target using TV or imaging infrared terminal
guidance, depending on what kind of sensor is installed. The radar
navigator aboard the B-52G used a joystick to "ride" the missile in to
its target while looking at the IR or TV display. The missile is
15.83 feet long and has an overall weight of about 3000 pounds. It
carries a warhead of about 1000 pounds in weight, and can have blast
fragmentation or penetrator warheads. There are four variants,
depending on the warhead/ guidance system mix--AGM-142A (blast
fragmentation/TV), AGM-142B (blast fragmentation/IIR), AGM-142C
(penetrator/TV), AGM-142D (penetrator/IIR). The Raptor has been in
production since 1989. The B-52G could carry four AGM-142 Raptors on
each of its underwing pylons (or three plus a datalink pod).
Engines: Eight Pratt & Whitney J57-P-43WB turbojets, each rated at 13,750
lb.s.t with water injection.
Performance: Maximum speed 636 mph at 20,800 feet, 570 mph at 46,000
feet. Cruising speed 523 mph. Stalling speed 169 mph. Initial climb
rate 5450 feet per minute. An altitude of 33,400 feet could br
reached in 19 minutes. Cruising speed 523 mph. Service ceiling at
combat weight 47,000 feet. Combat radius 4100 miles with 10,000 pound
bombload. Ferry range 7976 miles. Takeoff ground run 8150 feet.
Takeoff over 50-foot obstacle 10,400 feet.
Dimensions: Length 157 feet 7 inches (later increased to 160 feet
10.9 inches), wingspan 185 feet 0 inches, height 40 feet 8 inches,
wing area 4000 square feet.
Weights: 168,445 pounds empty, 302,634 pounds combat, 488,000 pounds
maximum takeoff.
Armament: Four 0.50-inch M3 machine guns with 600 rpg in tail turret.
Maximum offensive payload 50,000 pounds. Up to 20 Boeing AGM-86 ALCMs
could be carried, eight internally and three on each underwing pylon.
Internally, a clip of four B83 free-fall nuclear weapons could be
carried. In the conventional role, could be configured with the Heavy
Stores Adaptor Beam on the wing hardpoints so that nine 2000-lb Mk 84
bombs could be carried under each wing, with a further 27 internally.
Alternatively, 27 750-lb M117 or 1000-lb Mk 83 bombs could be carried
internally, with a further 24 on underwing positions fitted with the
redundant Hound Dog pylon and multiple ejector racks. AGM-86C and the
AGM-142 Have Nap EO guided missile can be carried on the HSABs.
Serials of B-52G:
57-6468/6475 Boeing B-52G-75-BW Stratofortress
c/n 464173/464180
57-6476/6485 Boeing B-52G-80-BW Stratofortress
c/n 464181/464190
57-6486/6499 Boeing B-52G-85-BW Stratofortress
c/n 464191/464204
57-6500/6520 Boeing B-52G-90-BW Stratofortress
c/n 464205/464225
58-158/187 Boeing B-52G-95-BW Stratofortress
c/n 464226/464255
58-188/211 Boeing B-52G-100-BW Stratofortress
c/n 4642256/464279
58-212/232 Boeing B-52G-105-BW Stratofortress
c/n 464280/464300
58-233/246 Boeing B-52G-110-BW Stratofortress
c/n 464301/464314
58-247/258 Boeing B-52G-115-BW Stratofortress
c/n 464315/464326
59-2564/2575 Boeing B-52G-120-BW Stratofortress
c/n 464327/464338
59-2576/2587 Boeing B-52G-125-BW Stratofortress
c/n 464339/464350
59-2588/2602 Boeing B-52G-130-BW Stratofortress
c/n 464351/464365
60-063/070 cancelled contract for Boeing B-52G
Specification of Boeing B-52G Stratofortress:
Sources:
