For 24 years, from 1966 through the 1980s, American leaders from field commanders to the President of the United States relied on data gathered by SR-71 Blackbird reconnaissance aircraft. Flying missions around the globe at speeds above Mach 3 and altitudes of 85,000 feet (26,000 m) or more, Blackbirds became a vital tool of international decision-making as their advanced photographic and electronic sensor systems collected intelligence for the Air Force and other federal agencies.
A congressional appropriation approved in late 1994 provided funds to return two or more SR-71s to reconnaissance flying. Subsequently, Lockheed Martin Skunk Works was awarded an Air Force contract to refurbish Blackbirds that had been kept in storage since 1990.
Origins of the SR-71 date back to the late 1950s when legendary Lockheed designer and Skunk Works founder Clarence L. "Kelly" Johnson proposed a high speed, high altitude alternative to supplement the Lockheed-built U-2 subsonic reconnaissance plane that would soon become vulnerable to Soviet missiles. As a result, the Blackbird family was initiated with the A-12, which first flew in April 1962. The single-seat A-12s were the smallest of the Blackbird series. Designed for reconnaissance missions, the A-12 spawned a two-place, armed version designated YF-12A, which was proposed as an interceptor. Although never adopted for this role, the YF-12s made important contributions as research aircraft, serving for more than a decade with NASA. It was the first aircraft capable of sustaining speeds above Mach 3.
A limited number of A-12 and YF-12 aircraft were produced before the design evolved into the SR-71, which first flew in 1964 and entered operational service in January 1966. Slightly larger than its predecessors, the SR-71 carried more fuel and featured chines that extended forward to the tip of the nose.
The aircraft remains a technological marvel. Practically every area of design required new approaches or breakthroughs in technology. To withstand high temperatures generated by friction in the upper atmosphere during sustained Mach 3 flight, the Blackbird required an array of specially developed materials including high temperature fuel, sealants, lubricants, wiring and other components. Ninety-three percent of the Blackbird's airframe consists of titanium alloy that allows the aircraft to operate in a regime where temperatures range from 450 degrees Fahrenheit at its aft midsection to 950 degrees Fahrenheit near the engine exhaust. The cockpit canopy, made of special heat resistant glass, must withstand surface temperatures as high as 640 degrees Fahrenheit.
Two Pratt & Whitney J58 turbojet engines with afterburners, each supplying more than 35,000 pounds of thrust, are housed in wing nacelles with diameters larger than the fuselage itself. Virtually every part of these complex powerplants had to be fabricated from special materials to meet the demands of triple-sonic flight. A translating (moveable) spike in each inlet controls airflow, retracting at speeds above Mach 1.6 to capture more air for the engines.
Although its many contributions to national security will never be fully revealed to the public, the SR-71 holds many world aviation records for speed and altitude.
In 1971 an Air Force crew demonstrated the SR-71's extended supersonic capabilities on a non-stop, 15,000-mile (24,140 km) flight -- the equivalent of a non-stop trip from San Francisco to Paris and back -- in 10-1/2 hours. Slowing to subsonic speeds for periodic aerial refueling, the Blackbird still averaged nearly 1,500 mph. For this feat the crew was awarded the 1971 Mackay trophy for "most meritorious flight of the year" and the 1972 Harmon International Trophy for the "most outstanding international achievement in the art/science of aeronautics."
On Sept. 1, 1974, an SR-71 flew from New York to London in 1 hour, 54 minutes, 56 seconds, smashing the previous trans-Atlantic speed record by nearly three hours! Returning to the U.S. on Sept. 13, 1974, the same aircraft established a world speed record of 3 hours, 47 minutes, 36 seconds for the 5,463 mile (8,790 km) flight from London to Los Angeles. It literally outraced the sun, landing some four hours before the time of day it took off.
Three SR-71s flown by three different crews set seven world speed and altitude records on July 27 and 28, 1976. They captured three records previously held by a specially modified Russian MiG 25 Foxbat and bettered four records held by the Lockheed/USAF YF-12. The new marks included absolute and class records of 2,193 mph (3,530 kph) for speed over a straight course and 85,069 feet (25,930 m) for altitude in sustained level flight.
In achieving these milestones the SR-71 was never extended to its ultimate capabilities. The aircraft used were stock, operational SR-71s, unlike the specially prepared aircraft commonly used to set such records. Air Force crews always stayed well within the SR-71's normal operational envelope.
In January 1990 the Air Force officially retired its fleet of SR-71s from service. On March 6, 1990, aircraft number 17972, the same aircraft that had set the 1974 records, was delivered to the Smithsonian Institution for permanent display at Dulles International Airport. Enroute, flying at "normal" operating speeds, this SR-71 set four more world records including a Los Angeles to Washington, D.C., flight time of 64 minutes, 20 seconds, averaging 2,144.8 mph (3,451.7 km/h).
That was the last SR-71 mission flown by an Air Force crew until the spring of 1995, when the crew retraining program began.
Between 1990 and 1995, NASA crews at the Dryden Flight Research Facility at Edwards AFB flew two SR-71s for training and scientific flights, and kept a third in storage. Those Blackbirds had been loaned to NASA by the Air Force when the military flying ceased.
The Skunk Works received funding to refurbish two Blackbirds to operational capability -- they were delivered to the U.S. Air Force in 1995.
See more SR-71 Blackbird photos on Flickr
Span: 55’ 7”
Length: 107’ 5”
Height: 18’ 6”
Weight: 140,000 lb.
Max Speed: 2,250 mph
Rate of Climb: 1,140 ft/min
Service Ceiling: 85, 000 + ft
Range: 3,000 + miles
- Lockheed Martin Archives
- Miller, J. (1982). Lockheed’s Skunk Works: The First Fifty Years. Arlington, Texas: Aerofax, Inc.
- National Museum of the United States Air Force