SR-71 Blackbird

SR-71 Blackbird – developed as a long-range strategic reconnaissance aircraft capable of flying at speeds over Mach 3.2 and at 85,000 feet. The first SR-71 to enter service was delivered in 1966 and retired in 1990. The USAF still kept a few SR-71s in operation up until 1998, after a few were brought back to service in 1995. NASA’s DFRC at Edwards AFB, CA flew the SR-71 from 1991 until late 2001.

The SR-71 was designed to minimize its radar cross-section, an early attempt at stealth design. Finished aircraft were painted a dark blue, almost black, to increase the emission of internal heat and to act as camouflage against the night sky. The dark color led to the aircraft’s call sign “Blackbird”.

The SR-71 was the world’s fastest and highest-flying operational manned aircraft throughout its career. From an altitude of 80,000 feet, it could survey 100,000 square miles per hour of the Earth’s surface. In addition, it was accurate enough to take a legible picture of a car’s license plate from this altitude. On 28 July 1976, an SR-71 broke the world record for its class, an absolute speed record of 2193.17 mph and an “absolute altitude record” of 85,069 feet.

• SR-71B was the trainer version of the SR-71. The dual cockpit to allow the instructor to fly the airplane.
• SR-72 – successor to the Blackbird – Using a new hypersonic engine design that combines turbines and ramjets, the company says that the unmanned SR-72 will be twice as fast as its predecessor with a cruising speed of Mach 6.
• J58 (JT11D-20A) Engine – The J58 powered nearly all of the Blackbirds. The J58 is the first engine designed to operate for lengthy periods in afterburner, and it is the first engine to be flight-qualified at Mach 3 for the Air Force.
• SR-71 Simulator – The SR-71 Simulator was used to train every crew member. Complete with both a Pilot and an RSO cockpit, the SR-71 simulator’s instrument panels are identical to those in the real aircraft. The simulator is now at NASA’s Dryden Flight Research Center, Edwards AFB, CA.

What’s the problem?
SR-71 (video 7:15) – The SR-71 was in service from 1964 to 1998 as top secret reconnaissance aircraft. Clarence “Kelly” Johnson was responsible for many of the design’s innovative concepts.

• Ask – A defensive feature of the aircraft was its high speed and operating altitude. If a surface-to-air missile launch were detected, standard evasive action was simply to accelerate. How fast was fast enough to outrun a missile? What factors of aircraft design are critical to achieving these speeds?
• Imagine – Designs for the SR-71 required lots of innovation. Many of the components did not exist or had not been used for building aircraft. What material properties were needed? Why was titanium selected? What problems had to be solved to accommodate the crew?
• Design, Build – Once most of the problems were identified, the designers and builders still had a lot to learn. They had to do a lot of testing and redesign when their original ideas didn’t work. Some problems were never “fixed” – the gas tanks always leaked on the ground and at low altitude. What did they need to solve the leaky gas tank problem? Why weren’t they able to?
• Improve – The gas tank leak would still be a problem today. There aren’t material for the seams and joints that could withstand the change in temperature up to 700 degrees.

That’s engineering

• afterburner – A device for burning excess carbon wastes produced by the engine so that air pollution is reduced.

Engineering ideas

• turbine, ramjet, unmanned, Mach, afterburner, man-machine integration, high temperature materials, titanium, polymers

Do It
Challenges for you to work on…

• design the “next generation SR-71”. What materials and processes are available now? How could the original design be improved based on today’s aerodynamics and technologies?
• SR-71 Trivia – test your knowledge on the Blackbird. Questions 1-80 are multiple choice. Use the ‘Check Your Answers’ form submission button at the bottom of each page to find out your score.

Learn more…

• Lockheed SR-71 Blackbird – an advanced, long-range, Mach 3 strategic reconnaissance aircraft developed by Lockheed. Clarence “Kelly” Johnson was responsible for many of the design’s advanced concepts. A defensive feature of the aircraft was its high speed and operating altitude, whereby, if a surface-to-air missile launch were detected, standard evasive action was simply to accelerate.
• SR-71 Blackbird Online Aircraft Museum – home to more than two thousand military aviation photos (over 850 of which are of the Lockheed Blackbirds) and fact sheets on more than a dozen military airplanes. The Blackbird Archive includes an in-depth look at the A-12, YF-12, and SR-71. It is also home to the SR-71 Flight Manual, a more than thousand page document now presented online.
• Lockheed SR-71 Blackbird – extensive article – Wikipedia