Whatever happened to the YF-12, the only Mach 3 fighter against bombers?

For a brief shining moment, the U.S. Air Force was on the verge of becoming the fastest, perhaps toughest pilot. fighter fighter jet of all time. The jet, the YF-12A, was one of several proposed variants in the SR-71 Blackbird family of high-speed aircraft in the 1960s. Yet an operational version of the aircraft never entered production, due to world events and the changing US nuclear The policy made it a questionable choice. Today, the YF-12A remains the closest the United States has ever come to producing an armed, Mach 3 capable aircraft.

On May 1, 1960, the Soviet Union shot down a U-2 spy plane over the USSR with its S-75 “Dvina” surface-to-air aircraft. rocket . Central Intelligence Agency pilot Francis Gary Powers piloted the high-flying but slow U-2 and took photographs of the Soviet Union. The CIA had hoped that the photographs would help formulate estimates of Soviet military power, but the capture of the powers and the loss of its aircraft meant that the U-2 was no longer invulnerable to the Soviet -air defense. A new aircraft was needed to continue the overflight program.

One of them was already in the works. In 1959, Lockheed’s Advanced Development Programs division, or its current name “Skunk Works,” presented the CIA with plans for a Mach 3 reconnaissance aircraft codenamed Oxcart. Later called the A-12, it was designed to perform the same mission as the U-2, with belly-mounted cameras that could photograph large areas of the ground below. But the A-12 would fly faster and be much harder to detect than its predecessor.

THE A-12 HAD A PIONEER AIRCRAFT DESIGN. The aircraft was 30 meters long, much longer than most tactical aircraft at the time, and used two new J58 turbojet engines embedded in the wings, an unusual design – engines are usually located in the fuselage. The two engines, which produced a total of 65,000 pounds of thrust in afterburner mode, would allow the aircraft to fly further at Mach 3.1, giving air defense systems like the S-75 very little time to respond. This was unprecedented in a time when the fastest was fighter jet at the time, the F-106 Delta Dart, could only support Mach 2.6. The large, blended design of the wings and body gave it plenty of internal volume for fuel, resulting in a range of 4,900 miles before needing to refuel. The plane would fly at an altitude of up to 35,000 feet – about three and a half times as high as Mount Everest – allowing the cameras to capture sweeping, panoramic views of the countryside below.

The A-12 was the first aircraft designed with stealth in mind. President Dwight D. Eisenhower, who had taken a special interest in the program, wanted the aircraft to be invisible to radar, to avoid embarrassing incidents involving the loss of an aircraft while entering enemy territory. A CIA study concluded that it was possible to reduce an aircraft’s radar signature, so Lockheed set to work modifying the A-12’s design, blending the wings and fuselage as much as possible to reduce the number reduce vertical surfaces. The design also traded its one large, upright tail wing, known as a vertical stabilizer, for two smaller angled stabilizers. Slanted stabilizers provided a smaller surface area for incoming radar waves, reflecting less energy back to enemy radars and making the aircraft more difficult to detect.

When the A-12 went into production, Lockheed quietly approached the Air Force about an armed variant of the new aircraft; until now, the Air Force had been left out of the effort to build an unarmed spy plane. The Air Force enthusiastically agreed, and three A-12s in production were diverted to a new, mysterious program known only as KEDLOCK. The plane would have an important mission in the nuclear age: eliminating enemy bombers.

THE THREAT OF AN ATTACK BY ATOMIC BOMB BECAME A REALITY B-29 long-range bombers once dropped an atomic bomb on the Japanese cities of Hiroshima on August 6, 1945, and on Nagasaki three days later. When the Soviet Union became the second country to develop nuclear weapons in 1949, the nuclear ones threat expanded against the US The Soviet R-7, the world’s first intercontinental ballistic missile, was still not much of a threat with a range of only 8,000 kilometers. Until the early 1960s, the heavy bomber was still the primary means of delivering an atomic bomb to the target, and the US continued to develop a defensive fighter capable of intercepting and downing all bombers.

In 1953, the Air Force began developing a new interceptor that would protect the United States and Canada from Soviet bomber attacks. The North American Aviation XF-108 Rapier was a large fighter designed to fly at Mach 3 and at an altitude of 60,000 feet. From its command position high in the sky, the Rapier would encounter Soviet bombers as they attempted to enter American airspace via the North Pole. A new, highly advanced radar, the AN/ASG-18, would allow the XF-108 to detect bombers 100 miles away and fly as low as 500 feet. The Rapier would be armed with three GAR-9A air-to-air missiles, each with a top speed of Mach 4. Each missile would carry a 0.25 kiloton warhead, which would guarantee the destruction of bombers. However, the ambitious program became too expensive and America’s changing nuclear strategy made the aircraft less necessary. In 1959, the Pentagon canceled the XF-108 Rapier.

Despite this setback, the prospect of a Mach 3 fighter had whetted the Air Force’s appetite for game-changing speed. And despite the loss of the Rapier aircraft, its radar and main weapons system, the AN/ASG-18 and GAR-9 missiles, showed promise. The stage was set for a new aircraft to carry the torch. In the deserts of Nevada, Lockheed had the answer to the ongoing need for a new high-speed interceptor.

The Lockheed A-12 is a retired high-altitude reconnaissance aircraft that could fly at Mach 3 and higher. Lockheed’s Skunk Works built it for the CIA and it was the precursor to the US Air Force’s YF-12 prototype interceptor.

THE KEDLOCK PROGRAM WAS A covert attempt to build an armed A-12. Lockheed workers kept three aircraft on the A-12 production floor, but separate from other projects, to secretly modify them. To confuse Soviet spies, they carried the designation A-11, that of an earlier, failed spy plane.

The YF-12s that the US concealed were very similar in appearance to the A-12, except for a round cone fairing, like that of the F-14 Tomcat fighter jet. This fairing hid the 40-inch nose-mounted AN/ASG-18 radar, which would not fit into the A-12’s existing nose design. This ultimately gave the YF-12 a dramatically different, fighter-jet-like shape.

The YF-12 traded the A-12’s Perkins Type I stereographic camera system for three GAR-9 missiles. They were stored in three cargo holds under and behind the cockpit. The YF-12 conducted its first unpowered drop test with a GAR-9 in April 1964, but the test failed: the rocket separated, nose up. If a rocket engine had ignited, it would have plowed straight into the aircraft’s cockpit. Less than a year later, however, a YF-12 scored its first air-to-air kill, downing a target 36 miles (58.2 kilometers) away. During a test in September 1965, a YF-12 launched another GAR-9, from an altitude of 70,000 feet at a speed of Mach 3.26, again scoring an intercept at a similar distance.

The YF-12 was always intended as a technology demonstrator. Now that the technology had been proven, engineers put the production version of the aircraft, the combination fighter-bomber, designated FB-12, on the drawing board. Even more ambitious than the YF-12, the FB-12 was intended to carry both the GAR-9 missile (later known as the AIM-47 Falcon) and the Short Range Attack Missile, or SRAM. SRAM was an air-to-surface nuclear strike missile with a range of about 130 miles and a 17-kiloton warhead – more than the 15-kiloton yield of the “Little Boy” Hiroshima bomb. SRAM would likely allow the FB-12 to fly deep into Russia and attack ground targets in conjunction with larger, nuclear-armed bombers.

The Air Force secured funding for 93 FB-12 fighters, but the planes were never built. Once again, a change in nuclear strategy meant that the planes no longer played a useful role. US military policy no longer called for shooting down enemy bombers, but revolved around a strategy that deterred the enemy from launching an attack. Meanwhile, a fighter-bomber armed with short-range nuclear missiles competed in the Air Force budget with the Mach 3-capable XB-70 Valkyrie bomber. The FB-12 was fast, but it couldn’t outrun the changing world. Despite coming tantalizingly close, the US government never built a Mach 3 interceptor.

As time went on, fighter jet design placed less emphasis on speed in favor of maneuverability, weapons capacity, aircraft range, and stealth. But you can still see one of the three surviving YF-12A on display at the National Museum of the US Air Force in Dayton, Ohio. NASA rented the other two for research purposes.

The A-12 line left a proud line of work in the 32 SR-71 Blackbirds – with their muscular capabilities, the Blackbird can be considered a direct descendant of the A-12. The Air Force got its Mach 3 planes anyway, at least until they were retired in 1999.