AIM-4 Falcon

The Hughes AIM-4 Falcon was the first operational guided air-to-air missile of the United States Air Force.

Development

Development of a guided air-to-air missile began in 1946. Hughes Aircraft was awarded a contract for a subsonic missile under the project designation MX-798, which soon gave way to the supersonic MX-904 in 1947. The original purpose of the weapon was as a self-defense weapon for bomber aircraft, but after 1950 it was decided that it should arm fighter aircraft instead, particularly in the interception role.

The first test firings took place in 1949, at which time it was designated AAM-A-2 and given the popular name Falcon. A brief policy of awarding fighter and bomber designations to missiles led it to be redesignated F-98 in 1951. In 1955 the policy changed again, and the missile was again redesignated GAR-1.

The initial GAR-1 and GAR-2 models entered service in 1956. It armed the F-89 Scorpion, F-101B Voodoo and F-102 Delta Dagger interceptors. The only non-U.S. users were Canada, Finland, Sweden and Switzerland, whose CF-101 Voodoo, Saab 35 Draken and Mirage IIIS carried the AIM-4 Falcon. Canada also hoped to use them on the CF-105 Arrow interceptor, that was never realized because of the Arrow's cancellation.

Unlike all but the newest generation of stealth-enabled fighters, fighters carrying the Falcon were often designed with internal weapons bays for carrying this missile. The Scorpion carried them on wingtip pods, while the Delta Dagger and Delta Dart had belly bays with a trapeze mechanism to move them into the airstream for launch (see picture above). The F-101B had an unusual bay arrangement where 2 were stored externally, and then the bay door would rotate to expose 2 more missiles. It is likely the F-111 internal bay would have accommodated the missile as well, but by the time of service, the Air Force had already dropped the Falcon for use against fighters, as well as the idea of using the F-111 as an air combat fighter. The F-22 Raptor and F-35 Lightning II both use internal weapons bays for missiles.

The GAR-1 had semi-active radar homing (SARH), giving a range of about 5 miles (8 km). About 4,000 rounds were produced. It was replaced in production by the GAR-1D (later AIM-4A), with larger control surfaces. About 12,000 of this variant were produced, the major production version of the SARH Falcon.

The GAR-2 (later AIM-4B) was a heat-seeker, generally limited to rear-aspect engagements, but with the advantage of being a 'fire and forget' weapon. As would also be Soviet practice, it was common to fire the weapon in salvos of both types to increase the chances of a hit (a heat-seeking missile fired first, followed moments later by a radar-guided missile). The GAR-2 was about 1.5 in (40 mm) longer and 16 lb (7 kg) heavier than its SARH counterpart. Its range was similar. It was replaced in production by the GAR-2A (later AIM-4C), with a more sensitive infrared seeker. A total of about 26,000 of the infrared-homing Falcons were built.

All of the early Falcons had a small 7.6 lb (3.4 kg) warhead, limiting their lethal radius. Also limiting them tactically was the fact that Falcon lacked a proximity fuze: the fuzing for the missile was in the leading edges of the wings, requiring a direct hit to detonate.

In 1958 Hughes introduced a slightly enlarged version of the Falcon, initially dubbed Super Falcon, with a more powerful, longer-burning rocket engine, increasing speed and range. It had a larger warhead (28.7 lb / 13 kg) and better guidance systems. The SARH versions were GAR-3 (AIM-4E) and the improved GAR-3A (AIM-4F). The infrared version was the GAR-4A (AIM-4G). About 2,700 SARH missiles and 3,400 IR Super Falcons were produced, replacing most earlier versions of the weapon in service.

The Falcon was redesignated AIM-4 in September 1962.

The final version of the original Falcon was the GAR-2B (later AIM-4D), which entered service in 1963. This was intended as a fighter combat weapon, combining the lighter, smaller airframe of the earlier GAR-1/GAR-2 weapon with the improved IR seeker of the GAR-4A/AIM-4G.

Vietnam

The USAF deployed AIM-4 during the Vietnam War on F-4D Phantom II, which carried it on the inner wing pylons. The missile's combat performance was very poor. The Falcon was designed to be used against bombers and its slow seeker cooling times requiring as much as 6 to 7 seconds to obtain a lock on a target rendered it largely ineffective against maneuvering fighters. Limited coolant supply meant that once cooled, the missile would soon expend its supply of liquid nitrogen, making it useless. The missile also had a small warhead, and lacked proximity fusing. As a result, only five kills were scored. The Falcon was also experimentally fired by the F-102 Delta Dagger against ground targets at night using its infrared seeker. The weapon was unpopular with pilots and was withdrawn in 1969, to be replaced by the Navy-designed AIM-9 Sidewinder.

An effort to address the limitations of AIM-4D led to the development in 1970 of the XAIM-4H, which had a laser proximity fuze, new warhead, and better maneuverability. It was cancelled the following year without entering service.

The AIM-4F/AIM-4G Super Falcon remained in USAF and ANG service, primarily with F-102 Delta Dagger and F-106 Delta Dart interceptors, until the final retirement of the 'Six' in 1988.

The AIM-4C was also produced for the Swiss air force (as the HM-58), where it was used on French-Swiss Mirage IIIS fighters, and the Swedish Flygvapnet (as the Rb 28) with Saab Draken aircraft.

A bigger, nuclear version of the Falcon carrying a 0.25-kiloton warhead was developed as the GAR-11 (later AIM-26 Falcon), while a long-range version was developed for the XF-108 Rapier and Lockheed YF-12 interceptors as the GAR-9 (later AIM-47 Falcon).

Specifications (GAR-1D/ -2B / AIM-4C/D)

• Length: 78 in (1.98 m) / 79.5 in (2.02 m)
• Wingspan: 20 in (508 mm)
• Diameter: 6.4 in (163 mm)
• Weight: 119 lb (54 kg) / 135 lb (61 kg)
• Speed: Mach 3
• Range 6 miles (9.7 km)
• Guidance: semi-active radar homing / rear-aspect infrared
• Warhead: 7.6 lb (3.4 kg) high explosive

Related content

Related Development:

• AIM-26 Falcon
• AIM-47 Falcon
• AIM-54 Phoenix

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "AIM-4 Falcon".