The SR-71 Blackbird

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The Lockheed SR-71, nicknamed the Blackbird, holds the record for the fastest airplane ever. A record which it set in 1976 and has held for 44 years. It also set a record for the highest altitude ever recorded for a sustained flight. 

Even though the plane hasn’t flown in over 20 years, it is still high in the consciousness of many aviation enthusiasts. 

Learn more about the SR-71 on this episode of Everything Everywhere Daily.

The story of the SR-71 Blackbird began on May 1, 1960, when Air Force pilot Francis Gary Powers was shot down in his U2 spy plane over the Soviet Union.

The Lockheed U-2 was designed to be a high altitude reconnaissance aircraft. The theory behind the U-2 was that it would fly so high, at over 70,000 feet, that it would be out of range of most anti-aircraft weapons.

Well, clearly that only worked for so long. 

After the U2 incident, the US needed some other spy plane, which avoided the problems of the U2. They needed something which could not only fly high but also extremely fast. 

The initial plane which was developed was the Lockheed A-12 OXCART. The A-12 looks suspiciously like the SR-71 and many of the engineering solutions used on the SR-71 were first developed for the A-12. I also have to give a side note, that the recent child of Elon Musk and Grimes had the name given to it of X Æ A-12, with the A-12 part being from the A-12 aircraft. 

The A-12 was a fine aircraft, but there were certain things it was lacking. For starters, it had to fly directly over a target, which wasn’t always desirable. Second, it only had one seat, so you couldn’t have a navigator to take care of all the non-flying parts of a mission. It also was smaller, which meant that it didn’t have the same range as the Blackbird.

The name SR-71 has a meaning. The SR part means “Strategic Reconnaissance”. The 71 part just means it was the 71st model, which was produced by Lockheed. The XB-70 Valkyrie preceded it, but it wasn’t a reconnaissance aircraft.

The Blackbird posed a host of engineering challenges that had to be overcome.

For starters, the plane was made mostly out of titanium. Titanium has unique properties for heat and strength. The problem was, most of the titanium in the world was produced by the Soviet Union at the time. They had to create dozens of dummy shell corporations all over the world, mostly in developing countries, to buy the titanium they required.

So, the Soviets actually supplied the materials for the United State’s most advanced spy plane.

In most aircraft, there is a separate bladder to contain fuel. For the Blackbird, to save weight, the fuselage itself was used as the fuel tank. The problem was when the plane was on the ground, fuel would be leaking out constantly. However, once it got airborne, and the temperature of the aircraft rose due to friction, the leaks would close up.

While they did try to seal the inside of the aircraft to minimize fuel leaks, eventually they gave up trying to stop it 100% and just created tolerances for how much fuel was allowed to leak. 

Speaking of fuel, they had to use special fuel which was only used for extremely special aircraft. The fuel was known as JP-7, and it was designed to be an incredibly stable fuel. This was necessary because of the high temperatures that the plane would experience while flying at extreme speeds. 

Also, because the fuel would leak out of the plane when it was on the ground, they didn’t want something which could easily ignite or cause a safety problem for the ground crew. 

The fuel was so stable at high temperatures that it was used as a coolant for parts of the aircraft during flight.

What limited the speed of the SR-71 wasn’t the engines or fuel; it was heat. 

When flying at speeds over Mach 3, the friction of the atmosphere on the fuselage of the plane created incredibly high temperatures. The average temperature on the skin of the plane could reach 600 degrees Fahrenheit or 320 degrees celsius. The window in the cockpit was an inch and a half thick oven glass.

The heat was why titanium was used on the body of the plane. As the plane would heat up, the titanium would expand. The plane in flight was actually four inches, or 10.6 centimeters longer than it was on the ground. You can see how fuel would have leaked out. 

The SR-71 had no weapons systems onboard. There were no guns or missiles installed. In the event that the aircraft was fired at by a surface to air missile, it would just change direction and accelerate. That’s it. At Mach 3 nothing could catch it. Even though some missiles would be faster, by the time they caught up to the plane, they would have spent all of their fuel.

Not a single Blackbird was ever lost to enemy action. 

The first flight of the SR-71 was on December 22, 1964. Over the course of its life, there were 32 of the planes manufactured. 

During its lifetime it was responsible for many record-breaking feats, many of which still stand today.

In 1976, the SR-71 set the world speed record for an air-breathing aircraft, in other words, it isn’t a rocket. It recorded a top speed of 2,193.2 miles per hour or 3,529.6 kilometers per hour, or Mach 3.4.  There was an unconfirmed case of a pilot flying an SR-71 over Libya in 1986 which achieved a speed of March 3.5 while evading a surface to air missile.

The greatest height achieved by the plane was 85,069 feet, which was also in 1976, and on the same day the speed record was set, but by a different flight on a different aircraft. 

In 1974, the plane set the speed record for flying from New York to London, which it did in 1 hour 54 minutes, and 56 seconds. By comparison, the Concorde’s best time for flying the same route was 2 hours and 52 minutes. 

The Blackbird flew thousands of missions over its lifetime, all over the world. However, it was an extremely expensive plane to operate. The turnaround for a single flight was about a week. The special fuel, the maintenance, and everything else meant that it couldn’t be used as frequently as was necessary.

At the same time, reconnaissance satellites got better, as did drones.  Most importantly, the need for real-time intelligence became more important. The SR-71 couldn’t be upgraded to allow for the type of real-time video, which you’ve probably seen since the first Gulf War. 

The plane was retired in 1988 and then unretired again in the early 90s before finally being retired one final time in the late 90s.

In 1990, one of the retired planes flew its last flight from Los Angeles to Washington where it would find its final home at the Smithsonian Museum. It made the flight in 64 minutes and 20 seconds.

The last flight ever of the SR-71 was on  October 9, 1999, when the last remaining plane, which was operated by NASA, was retired. 

One interesting question is if we will ever have a plane which is faster than the Blackbird?

There have been reports of a successor called the SR-72 which could fly up to March 6, but it would be an unmanned vehicle.

There may have been at least experimental planes that have gone faster than Blackbird. Many aircraft research projects are not made public, and if they are made public, it might not be for decades after the fact.

There have been rumors of a project called Aurora, which dealt with the creation of an experimental aircraft faster than the SR-71. While there is no proof of it, the one thing that you can’t hide with such an aircraft is the sonic boom, which can be picked up by seismic stations.

Dom Maglieri of the California Institute of Technology did an analysis of some sonic boom recordings and determined that they were created by an aircraft flying at  90,000 ft and flying between Mach 4 to Mach 5.2. 

There is work on new technologies which include ramjets and scramjets which in theory allow aircraft to fly up to Mach 10, but such planes are probably years away, assuming they ever get built.

Until those planes arrive, the SR-71 Blackbird will probably continue to hold the record for the fastest airplane that ever flew.


Executive Producer of Everything Everywhere Daily is James Makkala. 

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