| AIM-4 Falcon | |
|---|---|
 AIM-4D Falcon | |
| Type | Air-to-air missile |
| Place of origin | United States |
| Service history | |
| In service | 1956–88 (AIM-4F/AIM-4G) |
| Production history | |
| Manufacturer | Hughes Aircraft |
| Specifications | |
| Length | 1.98 m (6 ft 6 in) |
| Diameter | 163 mm (6.4 in) |
| Wingspan | 508 mm (20.0 in) |
| Warhead | 3.4 kg (7.5 lb) |
| Propellant | solid fuel rocket |
Operational range | 9.7 km (6.0 mi) |
| Maximum speed | Mach 3 |
Guidance system | semi-active radar homing andTail-chase engagementinfrared homing |
TheHughes AIM-4 Falcon was the first operational guidedair-to-air missile of theUnited States Air Force. Development began in 1946; the weapon was first tested in 1949. The missile entered service with the USAF in 1956.
Produced in both heat-seeking and radar-guided versions, the missile served during theVietnam War with USAFMcDonnell Douglas F-4 Phantom II units. Designed to shoot down slow bombers with limited maneuverability, it was ineffective against maneuverable fighters overVietnam. Lackingproximity fusing, the missile would detonate only if a direct hit was scored. Only five kills were recorded.
With the AIM-4's poor kill record rendering theF-4D ineffective at air-to-air combat, the fighters were modified to carry theAIM-9 Sidewinder missile instead, which was already carried on USAFF-4Cs, USN and USMCF-4 Phantom II andF-8 Crusader jet fighters. The Sidewinder was more effective in the fighter vs fighter role on the F-4 platform, and improved versions continue to serve the armed forces of the United States and numerous allied nations to this day.
Development of a guided air-to-air missile began in 1946.Hughes Aircraft was awarded a contract for asubsonic missile under the project designationMX-798, which soon gave way to thesupersonicMX-904 in 1947.
The original purpose of the weapon was as a self-defense weapon forbomber aircraft, which would carry a magazine of three missiles in the rear fuselage, and fire them through a long tube that led through the area that normally held the tail turret. In the case of theB-52, the missile contained a tuner for the bomber's A-3 rear-facing radar, and would follow the signal being reflected off the target aircraft using asemi-active radar homing (SARH) system.
At the same time that the original MX-798 had been released, a specification for a forward-firing missile forfighter aircraft had been released as MX-799. This had progressed to the point of testing prototype rounds, as theAAM-A-1 Firebird, when its subsonic speed andmanual guidance were realized to be serious problems.
The project was cancelled, and the recently released MX-904 was redirected to replace Firebird in the anti-bomber role. At this stage the weapon was still designed to be fired out of a tube, now leading from a weapon bay behind the nose-mounted radar with the launch tube exiting below the radar antenna. Instead of a magazine with multiple missiles, three missiles were placed in the tube tip-to-tail.
Housing in a tube presented several problems, but primary among them was that there was no way for the missile's seeker tolock-on before launch. The original concept would be firing againstinterceptor aircraft that were slowly approaching the B-52 and would be somewhere fairly close to directly behind the aircraft. In the case of a fighter, the target might not be so conveniently located, and with no way to know if it could see the target while inside the tube, this meant it might never lock-on properly.
Eventually, it was decided to abandon the tube-launched concept and mount the missile on the wings or in weapon bays that would point the missile at the target prior to launch. This change also allowed the seeker to useinfrared homing as well as SARH. Interchangeable seekers were developed, allowing an aircraft to carry either type, or both. Additionally, freed from the tube, the missile's wings were allowed to grow larger and took on the long delta form that it and its various descendants would carry into the 2000s.
The first test firings took place in 1949, at which time it was designatedAAM-A-2 and given the popular nameFalcon. A brief policy of assigning fighter and bomber designations to missiles led it to be redesignatedF-98 in 1951. In 1955, the policy changed again, and the missile was again redesignatedGAR-1.
The initialGAR-1 andGAR-2 models entered service in 1956.[1] It armed theNorthrop F-89 Scorpion,McDonnell F-101B Voodoo andConvair F-102 Delta Dagger andF-106 Delta Dartinterceptors. The only other users were Canada, Finland, Sweden and Switzerland, whoseCF-101 Voodoo,Saab 35 Draken andDassault Mirage IIIS carried the Falcon. Canada also hoped to use them on theAvro Canada CF-105 Arrow interceptor; however, this was never realized because of the Arrow's cancellation.
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. The F-101B had an unusual bay arrangement where two were stored externally, and then the bay door would rotate to expose two more missiles. It is likely theGeneral Dynamics F-111's 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 GAR-1 hadsemi-active radar homing (SARH), giving a range of about 5 mi (8.0 km). About 4,000 missiles were produced. It was replaced in production by theGAR-1D (laterAIM-4A), with larger control surfaces. About 12,000 of this variant were produced, the major production version of the SARH Falcon.
TheGAR-2 (laterAIM-4B) was a heat-seeker, generally limited torear-aspect engagements, but with the advantage of being a 'fire and forget' weapon. As would also beSoviet 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 theGAR-2A (laterAIM-4C), with a more sensitiveinfrared 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 that Falcon lacked aproximity 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 dubbedSuper 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 wereGAR-3 (AIM-4E) and the improvedGAR-3A (AIM-4F). The infrared version was theGAR-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 redesignatedAIM-4 in September 1962.
The final version of the original Falcon was theGAR-2B (laterAIM-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.
An effort to address the limitations of AIM-4D led to the development in 1970 of theXAIM-4H, which had a laserproximity fuze, new warhead, and better maneuverability. It was cancelled the following year without entering service.
A larger version of the Falcon carrying a0.25-kiloton nuclear warhead was developed as theGAR-11 (later designated theAIM-26 Falcon), while a long-range version was developed for theNorth American XF-108 Rapier andLockheed YF-12 interceptors as theGAR-9 (laterAIM-47 Falcon).
The Air Force deployed AIM-4 in May 1967 during theVietnam War on the newF-4D Phantom II, which carried it on the inner wing pylons and was not wired to carry theAIM-9 Sidewinder. The missile's combat performance was very poor. The Falcon, already operational onAir Defense Command aircraft, was designed to be used against bombers, and its slow seeker cooling times (as much as six or seven seconds to obtain a lock on a target) rendered it largely ineffective against maneuvering fighters. Moreover, it could be cooled only once. Limited coolant supply meant that once cooled, the missile would expend its supply ofliquid nitrogen in two minutes, rendering it useless on the rail. The missile also had a small warhead, and lacked proximity fusing. As a result, only five kills were scored, all with the AIM-4D version.[2] (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 from the onset and was supplemented or partially withdrawn in 1969, to be replaced in the F-4D by the Sidewinder after retrofitting the proper wiring. ColonelRobin Olds, USAF, commanding the F-4D-equipped8th Tactical Fighter Wing, was an outspoken critic of the missile and said of it:
By the beginning of June, we all hated the new AIM-4 Falcon missiles. I loathed the damned useless things. I wanted my Sidewinders back. In two missions I had fired seven or eight of the bloody things and not one guided. They were worse than I had anticipated. Sometimes they refused to launch; sometimes they just cruised off into the blue without guiding. In the thick of an engagement with my head twisting and turning, trying to keep track of friend and foe, I'd forget which of the four I had (already) selected and couldn't tell which of the remaining was perking and which head was already expiring on its launch rail. Twice upon returning to base I had the tech rep go over the switchology and firing sequences. We never discovered I was doing anything wrong.[3]
Colonel Olds became exasperated with the Falcon's poor combat performance. He ordered his entire fighter wing to rewire the F-4Ds to carry more reliable AIM-9 Sidewinders. Although it was an unauthorized field modification, the entire air force eventually followed his example.
Used from 1965 through 1972 in Vietnam, Falcons achieved their only kills duringOperation Rolling Thunder (1965–68) , with only 5 successful hits scored after 54 launches in aerial combat.[4][5]
| Date | Missile Firing Aircraft | AIM-4 Falcon Model | Downed Aircraft | Operating Unit |
|---|---|---|---|---|
| 26 Oct 1967 | F-4D Phantom II | AIM-4D | MiG-17 | USAF555th Tactical Fighter Squadron (TFS) |
| 17 Dec 1967 | F-4D Phantom II | AIM-4D | MiG-17 | 13th TFS |
| 03 Jan 1968 | F-4D Phantom II | AIM-4D | MiG-17 | 435th TFS |
| 18 Jan 1968 | F-4D Phantom II | AIM-4D | MiG-17 | 435th TFS |
| 05 Feb 1968 | F-4D Phantom II | AIM-4D | MiG-21 | 13th TFS |
The AIM-4 was also produced as theHM-55S (radar-guided) for theSwiss Air Force for use on theDassault Mirage IIIS,[6] and license-manufactured in Sweden for theSwedish Air Force (as theRb 28) to equip theSaab 35 Draken and37 Viggen. The seeker of the missile was also redesigned.
The AIM-4F/AIM-4G Super Falcon remained inUSAF andANG service, primarily withConvair F-102 Delta Dagger andF-106 Delta Dart interceptors, until the final retirement of the F-106 in 1988. These aircraft had been designed to carry the weapon and could not be easily converted to carry larger weapons like theAIM-9 Sidewinder orAIM-7 Sparrow, which were much longer.
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