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SR-71 Blackbird
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SR-71 Blackbird

SR-71 Blackbird
RoleStrategic Reconnaissance
Length107.42 ft32.74 m
Wingspan55.58 ft16.94 m
Height18.5 ft5.64 m
Wing area1,800 ft²167.2 m²
Empty65,000 lb29,484 kg
Loaded170,000 lb77,112 kg
Maximum take-off
EnginesTwo Pratt & Whitney; J58-1; (JT11D-20B) continuous-bleed afterburning turbojets
Power32,500 lb145 kN
Maximum speed2,100 mph (< Mach 3)3,380 km/h
Combat range2,982 mi4,800 km
Ferry range
Service ceiling> 85,000 ft> 25,908 m
Rate of climb

The Lockheed SR-71, unofficially known as the Blackbird, is a long-range, advanced, strategic reconnaissance aircraft developed from the Lockheed A-12 and YF-12A aircraft by Lockheed's Skunkworks, which was also responsible for the U-2 and many other advanced aircraft. In particular, the legendary "Kelly" Johnson was largely responsible for many of the concepts behind the aircraft. The SR-71 was one of the first stealthy aircraft, it incorporated radar absorbing materials and was shaped to have an extremely low radar signature.

The first flight of an SR-71 took place on December 22, 1964, and the first SR-71 to enter service was delivered to the 4200th (later, 9th) Strategic Reconnaissance Wing at Beale AFB, California, in January 1966. The U.S. Air Force retired its fleet of SR-71s on January 26, 1990, because of a decreasing defense budget and high costs of operation. The USAF returned the SR-71 to the active Air Force inventory in 1995 and began flying operational missions in January 1997. The planes were permanently retired in 1998.

Throughout its career, the SR-71 remained the world's fastest and highest-flying operational aircraft. From an altitude of 80,000 ft (24 km) it could survey 100,000 miles²/h (72 km²/s) of the Earth's surface. On July 28, 1976, an SR-71 set two world records for its class: an absolute speed record of 2,193.167 mph (3,529.56 km/h) and an absolute altitude record of 85,068.997 feet (25,929 m). When the SR-71 was retired in 1990, one was flown from Palmdale Airbase to go on exhibit at the Smithsonian Institute's National Air & Space Museum; in Washington, D.C., setting a coast-to-coast speed record at an average 2,124 mph (3,418 km/h). The entire trip took only 68 minutes.

The aircraft flew so fast and so high that if the pilot detected that a surface-to-air missile had been launched, the standard process of evasive action was, simply, "accelerate". No SR-71 aircraft are known to have been shot down.

On March 21, 1968 Major (later General) Jerome F. O'Malley and Major Edward D. Payne made the first operational SR-71 sortie. During its career, this aircraft accumulated 2,981 flying hours and flew 942 total sorties (more than any other SR-71), including 257 operational missions, from Beale AFB, California; Palmdale, California; Kadena Air Base, Okinawa and RAF (Base) Mildenhall, England. The aircraft was flown to the United States Air Force Museum in March 1990.

Thirty-two planes were built. Of these, 12 were lost in flight accidents but all crews ejected safely.

The original designation for the aircraft was the RS-71. However when the aircraft was announced by Lyndon B. Johnson on February 29, 1964, Johnson accidentally switched the letters for the name of the aircraft, which forced Lockheed to instantly change the name of the aircraft. While never intended for the bomber role, the -71 designation comes from the sequence used for bombers pre-1962, perhaps as a disinformation strategy.

Similar to the SR-71 were the A-11 and A-12 which were prototypes for the Blackbird, and the YF-12 which was an attempt to convert the SR-71 into a long range fighter.

Table of contents
1 Variants
2 Details
3 See also
4 External link


The most notable variant of the basic SR-71 design was the M-21. This was a SR-71 platform modified to carry and launch the D-21 drone, an unpiloted, faster and higher flying reconnaissance device. Confusingly, this variant was known as the M-21 when the drone was absent, and the MD-21 when it was attached to the plane. The D-21 drone was completely autonomous, having been launched it would overfly the target, travel to a rendevous point and eject its data package. The package would be recovered in midair by a C-130 Hercules and the drone would self destruct. The program to develop this system was canceled in 1966 after a drone crashed into the mother ship shortly after being launched, destroying the M-21 and killing the Launch Control Officer.

The only surviving M-21 is on display--along with a D-21B Drone--at The Museum of Flight in Seattle, USA.


The airframe was made of titanium obtained from the USSR during the height of the Cold war. The builder used all possible guises to prevent the Russians from knowing what it was to be used for. In order to keep the costs under control, they used a more easily worked alloy of titanium which softened at a lower temperature and then painted the aircraft black to dissipate heat.

The shape of the vehicle is designed so that the plane had a very small 'radar crossection'- essentially the SR-71 was an early stealth design. In addition, the geometry of the airframe is such that the engine inlets are inline with the shockwave from the nose of the aircraft. This compressed the air in a similar way to a ramjet and permitted higher performance. Indeed, at top speed more than 80% of the thrust was due to the ramjet effect. However, for this effect to operate successfully it also necessitated moveable inlet cones; incorrect positioning tended to make the engines 'unstart'. This caused at least one pilot to crack his helmet due to the sudden loss of thrust.

Due to the great temperature changes in flight, the fuselage panels were essentially loose. Proper alignment was only achieved when the airframe warmed up, due to the air resistance at high speeds, and the airframe then expanded several inches. Because of this, and the lack of a fuel sealing system that could handle the extreme temperatures, the aircraft would leak its specially formulated JP-7 jet fuel onto the runway before it took off. The aircraft would quickly make a short sprint, meant to warm up the airframe, and was then air-to-air refueled before departing on its mission. Cooling was carried out by cycling fuel behind the titanium surfaces at the front of the wings (chines). Nonetheless, once the airplane landed no one could approach it for some time as its canopy was still hotter than 300 degrees Celsius. Asbestos (non-fiberous) was also used, such as in non-ceramic automotive brakes, due to its high heat tolerance.

See also

External link

Related content
Related Development A-12 - YF-12 - M-21
Similar Aircraft
Designation Series XB-68 - B-69 - XB-70 - SR-71
Related Lists List of military aircraft of the United States - List of reconnaissance aircraft
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