AGM-28 Hound Dog

The AGM-28 was an air-launched cruise missile with a range approaching 800 miles. Known as Hound Dog, it was only carried by certain versions of the B-52 Stratofortress bomber. It was termed a “stand off” weapon in that it could be launched at targets keeping the bomber well away from any local defenses. The turbojet engines of the paired AGM-28s mounted beneath the inboard wings of a B-52 could be used to supplement its takeoff power, once airborne the bomber could refuel the missiles’ fuel tanks. No Hound Dogs were ever fired in anger, and they were withdrawn from use in 1978.

B-52F-70-BW 57-0163, 320th Bombardment Wing, Strategic Air Command, North American AGM-28A Hound Dog stand-off missile carrier

The first of the nuclear-tipped missiles carried by the B-52E, F, G and H models, Hound Dog was operational with SAC from September 1961 to 1976. One could be carried on a pylon suspended beneath each wing of a B-52G between the fuselage and the inboard engine nacelles. Two basic models of Hound Dog – GAM-77 (later AGM-28A) and GAM-77A (later AGM-28B) were produced. The missile was not capable of pin-point accuracy but it was designed as a standoff or ‘roll-back’ weapon to ‘soften’ enemy defences or target complexes up to 700 miles away during attacks by the bombers, much like the later AGM-69 SRAM. AGM-28B differed from the AGM-28A mainly in having a more accurate inertial guidance system and repositioning of the KS-120 astrotracker device from the missile pylon to the missile body. The B-52 could use Hound Dog’s Pratt & Whitney J52-P-3 turbojet engines for extra power on heavyweight take-offs and the missile’s tanks could be topped up by the B-52 in flight. Hound Dog had an inertial guidance system, which was updated by the B-52’s onboard system just prior to launch. The first Hound Dog-equipped B-52G unit was the 4135th Strategic Wing, at Eglin AFB, Florida, which first deployed in December 1959. On 17 January 1962 B-52Gs of the 4038th Strategic Wing at Dow AFB, Maine, became the first operational unit to go on alert status with the new missile. A total of 703 units were built and at its peak in 1963 the Hound Dog force numbered 593, but the missile was rapidly rendered obsolete and withdrawal from service was begun in 1967. At the end of June 1975 it was finally taken off alert duty and the last AGM-28 was scrapped in June 1978.

On 12 April 1960 a B-52G crew in the 4135th Strategic Wing at Eglin AFB, Florida, successfully launched a GAM-77 (AGM-28) Hound Dog air-launched attack missile as the climax of its 20½-hour captive flight to the North Pole and back. The 4135th Strategic Wing had been the first Hound Dog-equipped B-52G unit and first deployed in December 1959. The crew completed extensive tests of both the B-52G and the Hound Dog’s guidance system in temperatures as low as -7.5 degrees. On 14 December a B-52G of the 5th Bomb Wing at Travis AFB, California, completed an official record-breaking flight of 10,078.84 miles without refuelling in nineteen hours forty-four minutes. The aircraft, commanded by Lieutenant Colonel T. R. Grisson, flew a closed-circuit course from Edwards AFB, California, to El Paso, Texas, Andrews AFB, Maryland, Ernest Harmon AFB, Newfoundland, Eielson AFB, Alaska, Philip, South Dakota, and back to Edwards.

The first B-52H flew on 20 July 1960. Due to extensive rework and advanced technologies each B-52H model cost $9.2 million apiece. (The first ‘B’ models cost $14.4 million each and the B-52E eventually cost $5.9 million per aircraft.) One of the reasons for the B-52H order was a requirement to carry four GAM-87A Skybolt missiles on twin missile-launcher pylons. Though the pylons were developed the B-52s never carried Skybolts operationally, as the missile was cancelled in 1962. The B-52 force reverted to AGM-28 Hound Dogs for a further fourteen years and the new B-52H models were retrofitted for Hound Dogs in 1963.

Type

Intermediate-range, air-launched, ramjet-powered, single warhead cruise missile.

Development

Studies of the development of the GAM-77 Hound Dog began in 1956 when the USAF issued a General Operations Requirement for an air-to-surface missile for the B-52 bomber aircraft. The design requirements called for a 4 MT nuclear warhead (later reduced to 1 MT) to be carried a maximum range of 560 km, at M2.0 at over 17,000 m (55,000 ft) altitude. The contract for the development and production of Hound Dog was awarded to North American Aviation in 1957. The W-28, a 1 MT warhead, which had been developed for the Mk 28 bomb, was selected for Hound Dog. In 1958 growing concern about both the perceived unfavourable shift in the strategic balance and the increasing vulnerability of penetrating bombers prompted the USAF to accelerate development of the GAM-77, now designated AGM-28. In 1959 compatibility of the W-28 warhead to the Hound Dog missile was established and the first prototype missile was successfully tested. The first production AGM-28A Hound Dog was delivered to the Strategic Air Command (SAC) in December 1959 and SAC launched its first AGM-28A in February 1960. Because of certain deficiencies in the initial production missiles, development continued and an improved version GAM-77A designated AGM-28B was introduced into service in 1961.

The B-52 could carry two of the missiles, one on each of its two underwing inboard pylons, although the two missiles degraded the B-52 flight performance. However, the SAC crews found that they could shorten the B-52s take off run by using the Hound Dog engines in addition to the bombers eight engines, and bomber fuel could then be transferred to the missiles before they were launched.

Description

AGM-28 Hound Dog was a streamlined, long slender missile with a canard and delta wing configuration. Under the rear half of the fuselage was a large ramjet engine on a short pylon. The missile was 12.95 m long, had a body diameter of 0.72 m, a wing span of 3.70 m and a launch weight of 4,350 kg. Guidance was by a self-contained inertial system produced by North American’s Autonetics Division that operated the canard and wing control surfaces. The propulsion unit was the Pratt & Whitney J52 ramjet engine, which developed a thrust of 3,400 kg. The engine had a centre-body air intake and a variable propulsive nozzle to modulate the thrust and turbine temperature under different flight conditions. The missile payload was 790 kg and consisted of a W-28 nuclear warhead that had a yield of 1 MT.

When launched in its high-level profile, Hound Dog had a cruising speed of M 2.0 and range of 1,180 km. The maximum range at low level was 630 km with a speed of M 0.83 at 300 m altitude. The accuracy of the missile, 1,850 m CEP at full range, was probably adequate considering the yield of the warhead.

Operational status

The AGM-28A Hound Dog entered service with the USAF on B-52 bombers in 1960. This was followed by AGM-28B in 1961. The numbers of Hound Dog missiles in the B-52 fleet grew rapidly from 54 in 1960, rising to 593 in 1963 of which over 400 were AGM-28Bs, and by this time 29 SAC wings were operational with the AGM-28. Hound Dog production ended in 1963 and the number of missiles declined to 308 in 1976. The USAF phased out the Hound Dog in 1976, replacing it with the smaller AGM-69 SRAM. The last Hound Dog was retired for scrapping on June 15, 1978, from the 42nd Bomb Wing at Loring Air Force Base, Maine

Specifications

Length: 42 ft 6 in (1295.4 cm)

Diameter: 2 ft 4 in (71.12 cm)

Height: 9 ft 4 in (284.48 cm)

Maximum Span: 12 ft 2 in (370.84 cm)

Function: Air-to-Surface

Weight: 10,147 lbs (4,607 kg)

Warhead: W28 Nuclear Warhead, 1 MT

Guidance: Inertial

First Use Date: 1959

Producer: North American

Users: US Air Force

Other Designations: WS 131B, GAM-77

Status: Was operational, withdrawn from use 1978

Airborne cruise missile AGM-28A/B (GAM-77/GAM-77A) Hound Dog

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