Lockheed SR-71B Blackbird
The loss of Francis Gary Powers’ U-2A on 1 May 1960 underscored the fact that the U-2 was not as invulnerable to interception as originally hoped. If altitude was no longer a defense against Soviet air defenses, speed would be. Clarence “Kelly” Johnson, who had designed the U-2, was put to work with his legendary “Skunk Works” section of Lockheed to develop a very high-speed reconnaissance aircraft to supplement the U-2, named first the A-12—like the U-2’s use of the innocuous “utility” designation, the A-12 would use the outdated “attack” designation, though it carried no weapons. This designation was later changed as the design evolved, to the RS-71; this in turn was reversed to SR-71 by General Curtis LeMay, for strategic reconnaissance.
Work on the A-12/SR-71 was done in the strictest secrecy, although its existence was revealed in 1964 by President Lyndon Johnson. Virtually everything about the aircraft had to be invented on the spot, and even the tools used in its production had to be specially built first. The SR-71 was built of mostly light titanium, and design specifications were such that normal tools would damage the airframe. Emphasis was made on stealth and especially high speed: the SR-71’s intended normal operating speed was in excess of Mach 3, which at that time had only been achieved with the rocket-powered X-15.
To reach this speed, the aircraft would use J58 ramjets: once at altitude, the SR-71 would be accelerated to the point that the airflow over its shock-cone intakes would be forced into the engines at above the speed of sound. At speed above Mach 3, the SR-71 was more or less pulling itself through the air by brute force, with the engines only providing thirty percent of the thrust. At these speeds, heat was a real problem, as the fuselage would rapidly heat up. Titanium sheds heat better than most metals, and the SR-71 was designed with corrugated “skin” that would easily expand and contract with changing airspeed, heat, and altitude. Panels in the aircraft were deliberately designed to be loose on the ground and contract at altitude; fuel leaks on SR-71s were so commonplace that they were not remarked upon. Even the fuel and black paint scheme (actually a very dark blue) were placed and applied to diffuse heat away from leading edges.
The A-12, and the short-lived YF-12 interceptor, lacked the extended chines of the SR-71; these were emplaced to enhance the aircraft’s stealth techniques to reflect away radar. While in practice this did not work—Soviet radars could easily track the SR-71 through its heat plume—it actually made the aircraft more controllable and gave it increased lift. The SR-71 was not an easy aircraft to fly, but it was considerably easier than the U-2, and was generally reliable unless it lost an engine: the high speeds of the aircraft occasionally caused engine disintegrations, which would usually destroy the SR-71. It was also very unstable in bad weather, should it run into any after takeoff or on approach. Because of its high speed, the approach “pattern” for SR-71s to land at their home base of Beale AFB, California, had to begin at St. Louis, Missouri. Considerable restrictions were placed on supersonic flight over the continental United States, as Mach 3 sonic booms at 50,000 feet could shatter windows on the ground. The navigation system was adapted from that of the Skybolt air-launched nuclear missile, while cameras and side-looking radar was carried in the nose or the chines; these could be swapped out as the mission required. Extensive electronic countermeasures were also carried.
The SR-71 first flew in December 1964 and entered service in 1966—only six years after being ordered, an impressive achievement given its highly advanced nature. It was immediately committed to service over Vietnam under Operation Giant Scale. Attempts by the North Vietnamese to intercept the SR-71 were failures. Soviet attempts to intercept the SR-71 were no more successful: MiG-25 Foxbat interceptors could reach Mach 3, but Foxbat pilot Viktor Belenko later related the “ridiculous ease” that SR-71s could leave behind even the speedy MiG-25. Even later variants of SAMs and increasingly more sophisticated Soviet aircraft still could not intercept the SR-71, which quickly acquired the nickname Blackbird for its paint scheme; its snakelike chines earned it the nickname (and later callsign) Habu from Okinawans around Kadena airbase, where SR-71s often operated from, after the habu pit viper. Like the U-2s before them, SR-71s also operated from the legendary “Area 51” at Groom Lake, Nevada, and also led to a number of “UFO sightings” before knowledge of the aircraft became more commonplace.
One thing that the Blackbird could not outrace was the cost of operation: it required special JP-7 fuel, which in turn required specialized KC-135Q tankers to refuel them. The tooling for the aircraft had been destroyed on the order of Secretary of Defense Robert McNamara in 1967, which meant the 32 operational SR-71s had to be maintained by cannibalizing either the retired A-12 fleet or other Blackbirds to stay operational. It survived several attempts at forced retirement in the 1980s until the breakup of the Communist Bloc finally brought an end to SR-71 operations in 1989, though developments were underway to equip the Blackbird with synthetic-aperature radar and even more advanced engine designs that could propel it up to Mach 6. This retirement proved to be short-lived: during the First Gulf War, the USAF keenly felt the loss of the SR-71, which could provide better coverage of Iraq than satellites and was not as vulnerable as other reconnaissance platforms. Over heavy opposition from the USAF, three SR-71s were returned to service in 1993. After annual fights between the USAF, Congress, and President Bill Clinton over keeping the Blackbird in service, it was finally retired for good in 1998, except for two aircraft to be handed over to NASA for flight testing. Before the final Blackbird was grounded, it set a number of speed records across the United States, having already held the record for fastest transatlantic and transpacific crossings. NASA’s two aircraft only lasted a few years longer, with the end finally coming in 1999.
Of the 32 SR-71s produced (including SR-71A operational aircraft, SR-71B conversion trainers, and the single SR-71C “hybrid” trainer, converted from an A-12), 12 were lost in accidents. The remaining 20 aircraft have all been preserved in museums around the world.
This particular Blackbird, 61-7956, is unique--it is the only remaining SR-71B left in the world. (A converted A-12, the SR-71C "Bastard," is on display at Hill AFB, Utah.) As it was one of a few SR-71s sent to NASA after the first retirement of the Blackbird, it wears the more colorful NASA emblem on the tail; otherwise, it is as anonymous as most SR-71s. The Kalamazoo Air Zoo has given it appropriately mysterious nighttime lighting.
Lockheed SR-71B Blackbird
The loss of Francis Gary Powers’ U-2A on 1 May 1960 underscored the fact that the U-2 was not as invulnerable to interception as originally hoped. If altitude was no longer a defense against Soviet air defenses, speed would be. Clarence “Kelly” Johnson, who had designed the U-2, was put to work with his legendary “Skunk Works” section of Lockheed to develop a very high-speed reconnaissance aircraft to supplement the U-2, named first the A-12—like the U-2’s use of the innocuous “utility” designation, the A-12 would use the outdated “attack” designation, though it carried no weapons. This designation was later changed as the design evolved, to the RS-71; this in turn was reversed to SR-71 by General Curtis LeMay, for strategic reconnaissance.
Work on the A-12/SR-71 was done in the strictest secrecy, although its existence was revealed in 1964 by President Lyndon Johnson. Virtually everything about the aircraft had to be invented on the spot, and even the tools used in its production had to be specially built first. The SR-71 was built of mostly light titanium, and design specifications were such that normal tools would damage the airframe. Emphasis was made on stealth and especially high speed: the SR-71’s intended normal operating speed was in excess of Mach 3, which at that time had only been achieved with the rocket-powered X-15.
To reach this speed, the aircraft would use J58 ramjets: once at altitude, the SR-71 would be accelerated to the point that the airflow over its shock-cone intakes would be forced into the engines at above the speed of sound. At speed above Mach 3, the SR-71 was more or less pulling itself through the air by brute force, with the engines only providing thirty percent of the thrust. At these speeds, heat was a real problem, as the fuselage would rapidly heat up. Titanium sheds heat better than most metals, and the SR-71 was designed with corrugated “skin” that would easily expand and contract with changing airspeed, heat, and altitude. Panels in the aircraft were deliberately designed to be loose on the ground and contract at altitude; fuel leaks on SR-71s were so commonplace that they were not remarked upon. Even the fuel and black paint scheme (actually a very dark blue) were placed and applied to diffuse heat away from leading edges.
The A-12, and the short-lived YF-12 interceptor, lacked the extended chines of the SR-71; these were emplaced to enhance the aircraft’s stealth techniques to reflect away radar. While in practice this did not work—Soviet radars could easily track the SR-71 through its heat plume—it actually made the aircraft more controllable and gave it increased lift. The SR-71 was not an easy aircraft to fly, but it was considerably easier than the U-2, and was generally reliable unless it lost an engine: the high speeds of the aircraft occasionally caused engine disintegrations, which would usually destroy the SR-71. It was also very unstable in bad weather, should it run into any after takeoff or on approach. Because of its high speed, the approach “pattern” for SR-71s to land at their home base of Beale AFB, California, had to begin at St. Louis, Missouri. Considerable restrictions were placed on supersonic flight over the continental United States, as Mach 3 sonic booms at 50,000 feet could shatter windows on the ground. The navigation system was adapted from that of the Skybolt air-launched nuclear missile, while cameras and side-looking radar was carried in the nose or the chines; these could be swapped out as the mission required. Extensive electronic countermeasures were also carried.
The SR-71 first flew in December 1964 and entered service in 1966—only six years after being ordered, an impressive achievement given its highly advanced nature. It was immediately committed to service over Vietnam under Operation Giant Scale. Attempts by the North Vietnamese to intercept the SR-71 were failures. Soviet attempts to intercept the SR-71 were no more successful: MiG-25 Foxbat interceptors could reach Mach 3, but Foxbat pilot Viktor Belenko later related the “ridiculous ease” that SR-71s could leave behind even the speedy MiG-25. Even later variants of SAMs and increasingly more sophisticated Soviet aircraft still could not intercept the SR-71, which quickly acquired the nickname Blackbird for its paint scheme; its snakelike chines earned it the nickname (and later callsign) Habu from Okinawans around Kadena airbase, where SR-71s often operated from, after the habu pit viper. Like the U-2s before them, SR-71s also operated from the legendary “Area 51” at Groom Lake, Nevada, and also led to a number of “UFO sightings” before knowledge of the aircraft became more commonplace.
One thing that the Blackbird could not outrace was the cost of operation: it required special JP-7 fuel, which in turn required specialized KC-135Q tankers to refuel them. The tooling for the aircraft had been destroyed on the order of Secretary of Defense Robert McNamara in 1967, which meant the 32 operational SR-71s had to be maintained by cannibalizing either the retired A-12 fleet or other Blackbirds to stay operational. It survived several attempts at forced retirement in the 1980s until the breakup of the Communist Bloc finally brought an end to SR-71 operations in 1989, though developments were underway to equip the Blackbird with synthetic-aperature radar and even more advanced engine designs that could propel it up to Mach 6. This retirement proved to be short-lived: during the First Gulf War, the USAF keenly felt the loss of the SR-71, which could provide better coverage of Iraq than satellites and was not as vulnerable as other reconnaissance platforms. Over heavy opposition from the USAF, three SR-71s were returned to service in 1993. After annual fights between the USAF, Congress, and President Bill Clinton over keeping the Blackbird in service, it was finally retired for good in 1998, except for two aircraft to be handed over to NASA for flight testing. Before the final Blackbird was grounded, it set a number of speed records across the United States, having already held the record for fastest transatlantic and transpacific crossings. NASA’s two aircraft only lasted a few years longer, with the end finally coming in 1999.
Of the 32 SR-71s produced (including SR-71A operational aircraft, SR-71B conversion trainers, and the single SR-71C “hybrid” trainer, converted from an A-12), 12 were lost in accidents. The remaining 20 aircraft have all been preserved in museums around the world.
This particular Blackbird, 61-7956, is unique--it is the only remaining SR-71B left in the world. (A converted A-12, the SR-71C "Bastard," is on display at Hill AFB, Utah.) As it was one of a few SR-71s sent to NASA after the first retirement of the Blackbird, it wears the more colorful NASA emblem on the tail; otherwise, it is as anonymous as most SR-71s. The Kalamazoo Air Zoo has given it appropriately mysterious nighttime lighting.