AIM-4 Falcon

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AIM-4 Falcon
Image:AIM-4D.jpg A pair of AIM-4D Falcons in the weapons bay of the F-102 Delta Dagger fighter.
General characteristics
Length	1.98 m
Wingspan	508 mm
Diameter	163 mm
Launch Weight	54 kg / 61 kg
Warhead and guidance
Warhead	3.4 kg
Guidance	semi-active radar homing and rear-aspect infrared
Mobility
Speed	Mach 3
Range	9.7 km

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

1 Development
2 Vietnam
3 Specifications (GAR-1D/ -2B / AIM-4C/D)
4 Notes
5 Related content

[edit] 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 vogue for 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. user was Canada, whose CF-101 Voodoo and CF-105 Arrow interceptors carried the AIM-4 Falcon.

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.

[edit] Vietnam

The USAF deployed this weapon in Vietnam on F-4D Phantoms, which carried this on the two inner pylons <ref>Hasegawa's 1970s 1/72 Phantom II model kit included these parts, despite the limited time it was employed</ref>. Its combat performance in that conflict was very poor. Slow seeker cooling took as much as 6 to 7 seconds to lock onto a target, which might have been effective against a bomber, but an eternity in a dogfight. Limited coolant supply meant that once cooled, the missile would soon expend its supply of liquid nitrogen, making it useless. The small missile had a tiny warhead, and lacked proximity fusing. Only five kills were scored, though that is the most Falcon kills of any platform the Falcon was employed on, and most missiles of the Vietnam era were problematic in general, resulting in the redesign of the definitive air superiority version of the F-4E Phantom to accommodate the M61 Vulcan 20 mm cannon. The Falcon was also experimentally fired by the F-102 Delta Dagger against ground targets using IR seekers. It was not effective, and bases in South Vietnam were never attacked by air, nor was any US territory or its bases during its service life. The weapon was extremely unpopular with pilots, and was withdrawn in 1969. Many other USAF fighters used the superior Navy designed AIM-9 Sidewinder, which replaced the Falcon on the Phantom.

An effort to address the AIM-4D's limitations 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 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).

The most famous variant of the Falcon would be the AIM-54 Phoenix which armed the classic F-14 Tomcat. It could be fired simultaneously at six different targets as far as 100 miles away and 100,000 feet high, and was not retired until 2005 after adoption of the AMRAAM on the F/A-18 Hornet. Others would observe that it was rarely used, didn't hit anything when it was used, and suggested it was just <ref>[1]"the blank combat record of the Phoenix is consistent with the [nearly] blank record of the Hughes Falcon series of AAMs in general."</ref> another ineffective Falcon.