McDonnell GAM-72/ADM-20 Quail
The Quail was a bomber-launched decoy missile of the USAF, designed to appear on the enemy's radar screens as additional bombers, and thus confuse and degrade the air-defense system.
In 1955, the USAF started a major development effort for decoy missiles, which were intended to give almost identical radar images as real strategic bombers, and therefore confuse and saturate the enemy air defenses. The projects included the GAM-71 Buck Duck (a rocket-powered air-launched vehicle to be carried by the B-36 Peacemaker), the SM-73 Bull Goose (a ground-launched long-range jet-powered decoy), and the GAM-72 Green Quail. The latter was to become a turbojet-powered air-launched decoy for internal carriage by B-52 Stratofortress bombers. In February 1956, McDonnell was selected as prime contactor for the GAM-72, whose name had been shortended to Quail by that time (the names of the other two decoy projects are also often quoted without the "first name"). Captive tests with B-52s began in July 1957, and the first free glide flight of an XGAM-72 prototype occurred in November 1957. The first successful powered flight in August 1958 was followed by the initial production contract for the GAM-72 Quail in December 1958. In September 1960, the USAF received its first production Quails, and in February 1961, the first B-52 squadron with Quail decoys was operational.
Photo: USAF | Photo: Boeing | |
GAM-72 (ADM-20A) |
The GAM-72 was powered by a General Electric J85-GE-3 turbojet engine. Its slab-sided fuselage and twin dorsal and ventral fins produced a large radar cross section similar to that of a B-52. The wings and fins of the Quail could be folded, reducing the overall dimensions to 3.94 m x 0.74 m x 0.66 m (155 in x 29 in x 26 in). This allowed the carriage of up to eight decoys in the B-52's weapons bays, although the operationally used quantity was four decoys per aircraft. The Quails were located in the extreme rear of the B-52's bay, and could be lowered out of the bay before launch for wing unfolding and engine start. The Quail could be preprogrammed on the ground to perform two turns and one speed change during its flight to a range of up to 825 km (445 nm). Additionally, it carried an ECM package including of a radar repeater, and later versions also had chaff dispensers and a heat source (to simulate the B-52's IR signature).
The J85-GE-3 engines of the original GAM-72 suffered from serious reliability problems, and the engine was therefore modified into the J85-GE-7 version. Quails equipped with the new engine were designated GAM-72A. The GAM-72A was also about 90 kg (200 lb) heavier than the GAM-72, and had a slightly smaller wing area, reducing the maximum range to about 650 km (350 nm). The first GAM-72A flew in March 1960, and almost all of the 550+ production Quails (except for the first 24 missiles only) were built as GAM-72As. During 1963, all available GAM-72As were modified for low-level operations by the addition of a barometric switch for terrain avoidance. In this confuguration the Quail was redesignated as GAM-72B.
Photo: Pima Air & Space Museum |
ADM-20C |
In June 1963, all Quail missiles were redesignated in the ADM-20 series as follows:
Old Designation | New Designation |
---|---|
GAM-72 | ADM-20A |
GAM-72A | ADM-20B |
GAM-72B | ADM-20C |
The ADM-20 was a relatively effective decoy against 1960s technology radars. However, in a USAF test in 1972, the Air Force radar operators were able to correctly identify the decoys in 21 out of 23 cases. Because the Quail was apparently no longer a useful decoy, the Air Force began its phase-out, and in 1978 the last ADM-20C had left the USAF inventory. A total of about 600 Quail decoys of all variants were built.
Specifications
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for ADM-20B/C (except where noted):
Length | 3.94 m (12 ft 11 in) |
Wingspan | 1.65 m (5 ft 5 in) |
Height | 1.02 cm (3 ft 4 in) |
Weight | 540 kg (1200 lb); ADM-20A: 450 kg (1000 lb) |
Speed | Mach 0.95 |
Ceiling | 15200 m (50000 ft) |
Range | 650 km (350 nm); ADM-20A: 825 km (445 nm) |
Propulsion | General Electric J85-GE-7 turbojet; 10.9 kN (2450 lb) ADM-20A: General Electric J85-GE-3 turbojet; 10.9 kN (2450 lb) |
Main Sources
[1] Kenneth P.Werrell: "The Evolution of the Cruise Missile", Air University Press, 1985
[2] Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
[3] Dennis R. Jenkins, Brian Rogers: "Boeing B-52G/H Stratofortress", Aerofax, 1990
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Last Updated: 21 November 2002