The AIM-26 Falcon was the only guided nuclear-armed air-to-air missile ever deployed by the USAF. Development of a nuclear-armed derivative of the AIM-4 Falcon family was first planned in 1956, when Hughes was contracted to develop the XGAR-5 and XGAR-6 missiles. These missiles were intended to be significantly larger than the standard Falcon (length/diameter increased from 2.0 m/0.16 m (80 in/6.4 in) to about 3.5 m/0.30 m (140 in/12 in)), and were to be used against high and fast-flying missiles and bombers. The two variants were identical, except for the guidance method - semi-active radar homing for the XGAR-5, and infrared homing for the XGAR-6. However, development was cancelled early in the design phase.
Development of a nuclear-armed Falcon derivative started again in 1959, when it was decided that USAF interceptors needed a head-on kill capability against enemy bombers. This dictated radar homing (IR seekers of the day could only home on hot exhaust), but this was considered too inaccurate for a conventionally armed missile. Therefore a low-yield W-54 nuclear warhead was planned for the missile, which was designated as GAR-11.
The GAR-11 was slightly larger, and significantly heavier than the original Falcon. Testing of the XGAR-11 proceded without problems during 1960, and in 1961, the GAR-11 became operational with F-102 interceptors. The nuclear warhead, and the inherent all-weather capability of the SARH guidance made the GAR-11 the most powerful air-to-air missile ever deployed. Detonation of the warhead was triggered by a radar proximity fuze.
However, the nuclear warhead also had a major disadvantage - the missile could not be used against low-flying aircraft over friendly territory. Therefore the conventionally armed GAR-11A was developed in parallel. The GAR-11A was relatively little used by the USAF, but was exported to Sweden (and license-built there) as RB-27.
GAR-11 (AIM-26A)
GAR-11A (AIM-26B)
In 1963, the GAR-11 Falcon missiles were redesignated in the AIM-26 series. The XGAR-11, GAR-11, and GAR-11A became the XAIM-26A, AIM-26A, and AIM-26B, respectively.
Improvements in radar-homing in the late 1960's made the AIM-7 Sparrow missile effective in frontal attacks. This fact, together with the AIM-26A's unsuitability against low-level threats, led to a quick phase-out, and by 1971 the AIM-26A was no longer in service. The Swedish RB-27 (AIM-26B) was used by J 35 Draken fighters until the late 1990's. In total, about 4000 AIM-26 missiles of both variants were produced.
Data for GAR-11 (AIM-26A):
Length 2.14 m (84.2 in)
Wingspan 0.620 m (24.4 in)
Diameter 0.279 m (11 in)
Weight 92 kg (203 lb)
Speed Mach 2
Range 8-16 km (5-10 miles)
Propulsion Thiokol M60 solid-fuel rocket; 26 kN (5800 lb)
Warhead W-54 nuclear fission warhead (0.25 kT *)
*The 250 T yield is the figure quoted by most public sources. However, according to a first-hand account of an individual who worked with the weapon, the true nominal yield was actually 1.5 kT.