| Is Missile: | yes |
| AIM-47 Falcon | |
| Origin: | United States |
| Type: | Air-to-air missile |
| Used By: | United States Air Force (testing) |
| Designer: | Hughes Aircraft |
| Design Date: | 1957-1966 |
| Propellant: | Solid fuel rocket |
| Spec Label: | XAIM-47A |
| Engine: | Lockheed XSR13-LP-1 |
| Weight: | 818lb |
| Length: | 12feet |
| Diameter: | 13.5inches |
| Wingspan: | 33inches |
| Speed: | Mach 4 |
| Vehicle Range: | 100miles |
| Filling: | 100lb |
| Guidance: | Semi-active radar homing, terminal infrared homing |
| Detonation: | Proximity fuse |
| Launch Platform: | Lockheed YF-12, North American XF-108 Rapier |
The Hughes AIM-47 Falcon, originally GAR-9, was a very long-range high-performance air-to-air missile that shared the basic design of the earlier AIM-4 Falcon. It was developed in 1958 along with the new Hughes AN/ASG-18 radar fire-control system intended to arm the Mach 3 XF-108 Rapier interceptor aircraft and, after that jet's cancellation, the YF-12A (whose production was itself cancelled after only 3 vehicles). It was never used operationally, but was a direct predecessor of the AIM-54 Phoenix used on the Grumman F-14 Tomcat.
In the early 1950s, the United States Air Force developed requirements for a high speed, high performance interceptor aircraft, originally called the LRI-X. In 1957, Hughes won the contract to supply the weapons system for this aircraft. This system consisted of the GAR-X missile and the YX-1 radar and fire control system. The original missile design had a range of 15 to 25 miles (25 to 40 km), and could be equipped with a conventional warhead or a 0.25 kiloton version of the W42 nuclear warhead. When the North American XF-108 Rapier was announced as the winner of the LRI-X contest in April 1958, the Hughes entries were redesignated GAR-9 and AN/ASG-18 on the same day. The F-108 was canceled in September 1959, but the Air Force decided to continue development of the missile system with both warheads.[1]
During its development, the capabilities of the new missile grew tremendously. Growing much larger, the missile's range was extended to 100 miles (160 km), using the Aerojet-General XM59 solid-fuel motor. The SARH seeker was a powerful system of its own, with the resolution to be able to lock onto a 100square feet target at 63 nm (116 km). Some consideration was given to the addition of a passive infrared homing seeker to improve terminal performance but that would have required the missile to grow by 180lb and two inches in diameter, making it too large for the F-108's weapon bay. The W42 nuclear version was dropped in 1958 in favor of a 100lb high-explosive design.[1]
Problems with the motor during development led to the brief consideration of using a storable liquid-fuel rocket design, but was replaced instead by the Lockheed XSR13-LP-1 solid rocket. This lowered the top speed from Mach 6 to Mach 4. In this form, the GAR-9 started ground firings in August 1961. For air-launch testing at supersonic speeds the Republic XF-103 had originally been proposed as a test platform, but this aircraft was canceled before reaching the prototype stage. Instead, B-58 Hustler s/n 55-665 was modified to house the AN/ASG-18 radar in a large protruding radome that gave it the nickname "Snoopy", and in-flight launches started in May 1962.
In 1960 Lockheed started development of the Lockheed YF-12 interceptor, as a lower-cost replacement for the F-108. The GAR-9/ASG-18 were moved to this project. The F-12 would have featured four flip-open internal weapons bays on the chines behind the cockpit, one of these filled with electronics. The F-12B bays were too small for the GAR-9, so the GAR-9B was developed with flip-out fins to reduce its diameter. It weighed 365kg (805lb).[2]
Test firings of the GAR-9A from the prototype F-12As resulted in six kills from seven launches, the lone miss due to a missile power failure (there were several non-guiding test launches as well). The missile was renamed AIM-47 in late 1962 as part of the transition to common naming for aerospace vehicles across the U.S. Department of Defense in 1962. The last launch was from a YF-12 flying at Mach 3.2 and an altitude of 74400feet at a QB-47 target drone 500feet off the ground.[3]
In 1966, the F-12 project was canceled just as the F-108 had been. Another project which expressed an interest in the design was the XB-70 Valkyrie, a bomber which could have carried the AIM-47 for self-defense. This aircraft was also canceled after Soviet deployment of effective high-altitude surface-to-air missiles made high-altitude attacks on the Soviet Union impractical.
Hughes had built 80 pre-production AIM-47 missiles.
The AIM-47 was used as a base for the AIM-54 Phoenix (originally the AAM-N-11), intended for the General Dynamics F-111B. This project was also canceled in 1968, but the weapon system finally found a home on the F-14 Tomcat, entering service in the early 1970s.
In 1966, the basic airframe was adapted with the seeker from the AGM-45 Shrike and the 250lb warhead from the Mk 81 bomb to create the high-speed AGM-76 Falcon anti-radar missile, although this did not see service.[4]