ADM-20 Quail - Design

Design

McDonnell Aircraft Corporation submitted a design which included a cropped-delta-wing decoy constructed largely of fiberglass and carried internally within a B-52. The following month on February 1, 1956, the McDonnell Aircraft Corporation was awarded a contract to develop Weapon System 122A which included the GAM-72 Green Quail missile. In June 1956 General Electric was selected as the engine contractor for the GAM-72. Guidance components were built by Summers Gyroscope and the countermeasures equipment by Ramo-Wooldridge Corporation.

The GAM-72 was designed with a high-mounted delta wing and no horizontal stabilizer. A slab-sided fuselage and two sets of vertical stabilizers contributed to the GAM-72s ability to simulate the radar cross section of a bomber. Initially the GAM-72 was powered by a YJ85-GE-3. This jet engine produced 2,450 lbf (10.9 kN) of thrust with a thrust-to-weight ratio goal of (6:1).

The GAM-72s guidance system could be pre-programmed on the ground to execute two turns and one speed change during a flight time of 45 to 55 minutes. Flight duration depended on altitude. The GAM-72 was designed to operate at altitudes between 35,000 ft (10,668 m) to 50,000 ft (15,240 m) at speeds between Mach 0.75 to Mach 0.9. Range varied between 357 nm and 445 nm (661 to 716 km), also depending on altitude.

Two GAM-72s with folded wings and stabilizers were packaged together for mounting in the bomber weapons bay. Before launch the bomber's radar navigator lowered the GAM-72 using a retractable arm from the airplane's weapons bay into the slipstream below the aircraft. The wings and stabilizers of the GAM-72 were unfolded, the jet engine was started, and the missile was launched.

Flight testing of the XGAM-72 began in July 1957 at Holloman Air Force Base and the adjacent White Sands Missile Range. Initially testing involved the XGAM-72 being captively carried by a B-52. The first glide flight of the XGAM-72 occurred in November 1957. Three test launches were completed in 1957. The first successful powered flight of the XGAM-72 occurred in August 1958. This flight lasted 14 minutes and covered 103 nautical miles (191 km). A total of ten test flights occurred in 1958, seventeen flights in 1959, with the final four flights being completed in 1960. Operational testing then moved to Eglin Air Force Base, Florida, United States where the 4135th Strategic Wing launched a GAM-72 on June 8, 1960.

McDonnell Aircraft received a production contract for the GAM-72A on December 31, 1958. Reliability problems encountered during testing resulted in McDonnell replacing the J85-GE-3 with the J85-GE-7 engine in the production GAM-72A. The GAM-72A was also about 200 lb (90 kg) heavier than the GAM-72. This increase in weight when combined with a slightly smaller wing area reduced the maximum range of the GAM-72A to 402 statute miles (647 km). The first production GAM-72A flight was in March 1960. The final GAM-72A was delivered by McDonnell Aircraft on May 28, 1962. A total of 616 GAM-72A missiles were produced by McDonnell Aircraft. The inventory of GAM-72As in the USAF peaked at 492 in 1963.

During 1963 all remaining GAM-72A missiles were modified to the GAM-72B configuration. A barometric switch for terrain avoidance was added so the GAM-72B could operate at lower altitudes.

In 1963 the GAM-72 was re-designated the ADM-20