The Lockheed A-12 family, known as the Blackbirds, were designed by Clarence “Kelly” Johnson. They were constructed mostly of titanium to withstand aerodynamic heating. Fueled by JP-7, the Blackbirds were capable of cruising at Mach 3.2 and attaining altitudes above 80,000 feet. The first version, a CIA reconnaissance aircraft that first flew in April 1962 was called the A-12. An interceptor version developed in 1963 under the designation YF-12A. A USAF reconnaissance variant, called the SR-71, was first flown in 1964. The A-12 and SR-71 designs included leading and trailing edges made of high-temperature fiberglass-asbestos laminates.
The SR-71 Blackbird, the United States’ renowned reconnaissance aircraft capable of speeds of Mach 3.3, remains until today the world’s fastest ever aircraft.
Its record speed is closely followed by that of the Soviet MiG-25 interceptor – which remains the world’s fastest combat aircraft. A U.S. military project in the late 1960s, however, was set to develop a combat jet faster even that the MiG-25’s, with the ability to approach hypersonic speeds at Mach 4.
With the F-108 interceptor program having been canceled due to budgetary constraints, the U.S. Air Force still requested a modern high-speed interceptor with air to air combat capabilities.
This combat adaptation of the Blackbird, called the F-12, was set to be equipped by Lockheed Martin with a powerful AN/ASG-18 radar capable of detecting aerial targets over 800km away.
The interceptor was also set to carry four long-range AIM-47 missiles, with a range of over 160km and a potent 100-pound high explosive warhead.
Such a platform was ideally suited to intercepting Soviet bombers and reconnaissance aircraft near the U.S. mainland, with its high speed allowing it to respond quickly to any airborne threats detected.
The U.S. Air Force placed an order for 93 F-12 interceptors, though these were canceled when Defence Secretary Robert McNamara refused to released the necessary funds.
As a result, only three prototype interceptors were ever produced, and none ever entered service in the Air Force. The systems developed for the F-12 did, however, serve in other potent air combat platforms.
The formidable AWG-9 radar and long-range AIM-54 Phoenix missiles used by the F-14 Tomcat air superior fighter were based closely on the technologies in the F-12 interceptor.
Largely as a result of these technologies, the F-14 would go on the become one of the most lethal American combat aircraft of all time – in the Iran-Iraq war achieving a phenomenal 160 kills against Iraqi fighters for only three losses. Partly as a result of the F-12 program’s cancellation, the USSR and today Russia have remained well ahead in the capabilities of their interceptors.
Had the F-12 entered service, however, the Russian advantage in this field may today be less absolute?
With the next generation of aircraft prizing maneuverability, and from the 1980s stealth, far more relative to speed – a combat aircraft capable of exceeding the Mach 3.2 record set by the MiG-25 in the late 1960s has yet to enter service anywhere in the world.