The Fastest Jet Aircraft in the World

How the Lockheed SR-71 Blackbird's design helped pilots go higher and further than ever before.

SR-71 Blackbird SR-71 BlackbirdSmithsonian's National Air and Space Museum

The Lockheed SR-71 Blackbird is the fastest jet aircraft in the world, reaching speeds of Mach 3.3--that’s more than 3,500 kph (2,100 mph) and almost four times as fast as the average cruising speed of a commercial airliner.

Key elements of the SR-71's design made this possible.

SR-71 Blackbird SR-71 BlackbirdSmithsonian's National Air and Space Museum

The secret to the aircraft’s speed and agility is largely in its unique engine inlets--a duct where air in brought into the engine. To handle the dramatic changes in speed and pressure, air is slowed to subsonic speeds before entering the SR-71’s jet engines.

Lockheed SR-71 Blackbird: AfterburnerSmithsonian's National Air and Space Museum

The exhaust from the SR-71’s jet engines creates a diamond pattern. That’s due to the extra thrust provided by its supersonic afterburner. This creates successive shock waves that show up as the diamond pattern. The SR-71 engines fly continuously in afterburner, except when refueling.

SR-71 Blackbird SR-71 BlackbirdSmithsonian's National Air and Space Museum

Flying more than three times the speed of sound means that the aircraft has to withstand heat. The SR-71 generates 316° C (600° F) temperatures on its external surfaces, which are enough to melt conventional aluminum airframes.

That's why the SR-71's external skin is made of titanium alloy that shield an internal aluminum airframe.

The tires, which retract into the wings during flight, also have to keep from melting.

To create the tires, latex was mixed with aluminum, and filled with nitrogen. The tire pressure on the SR-71 was 415 psi--10 times more than an average set of car tires.

With its ability to reach high speeds and high altitudes, the SR-71 was used to gather intelligence for the U.S. military during the Cold War. The aircraft could survey up to 160,934 square kilometers (100,000 square miles) of territory in just one hour. Its stealthy design also reduced its chances of being detected on radar.

Lockheed SR-71 Blackbird: Pressure SuitSmithsonian's National Air and Space Museum

During missions aboard the SR-71, pilots flew so high that they had to wear special pressure suits that were actually modified spacesuits.

SR-71 Blackbird SR-71 TakeoffSmithsonian's National Air and Space Museum

As Museum docent and former SR-71 pilot Buz Carpenter described: “Powerful acceleration pushed you against the seat during takeoff. The faster you flew, the more sensitive the aircraft became and required more concentration and care.”

SR-71 Blackbird Lockheed SR-71 Blackbird Skunk Works LogoSmithsonian's National Air and Space Museum

While the skunk logo on the SR-71’s tail didn’t help it reach peak speeds, it is part of the aircraft’s unique history.

This little skunk is the official logo of the Lockheed secret projects factory, nicknamed “Skunk Works.” The Lockheed factory was adjacent to an industrial plastics plant, which let off a terrible odor, thus the name.

Tour of the SR-71Smithsonian's National Air and Space Museum

Tour the Blackbird with one of its pilots or see it in person at the Museum.

Learn More About the Blackbird

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