The Lockheed SR-71 Blackbird: A Legendary Military Plane Forged from Failure

The Lockheed SR-71 Blackbird was a fast, stealthy, and high-flying spy plane that remains the fastest manned aircraft in history. The Blackbird could fly at speeds of Mach 3.3, or nearly three times the speed of sound. It could also fly higher than any other manned aircraft — at peak altitudes above 85,000 feet, where air is so thin pilots must wear pressure suits to avoid developing hypothermia and becoming unable to perform essential functions. Even more impressively, the SR-71 can do this all without an afterburner — it’s that efficient. The SR-71 was retired from service in 1999 due to cost and the effectiveness of newer spy planes that have since replaced it. However, even with its retirement from active service, the SR-71 remains one of the most well-known military aircraft still in operation today. Let’s take a closer look at how this legendary plane was forged from failure.

The birth of a legend

The idea for a new high-speed, high-altitude jet was born of failure. The Air Force had commissioned Lockheed to build a high-altitude reconnaissance aircraft in 1956, but their design turned out to be a failure. The Lockheed F-108 was a single-seat, high-altitude interceptor capable of speeds of over 2,000 mph. However, it was plagued with development problems, including issues with its engines and overall weight. Because of its failure as an interceptor, the U.S. Air Force took an interest in the F-108 as a high-altitude reconnaissance aircraft, and Lockheed was given the task of converting the aircraft. The modified F-108, now designated the RS-71, would require a new engine because the original J-58 engines were too heavy for the mission.

From F-108 to the SR-71

The engines for the SR-71 were built by Pratt & Whitney, and were a type of engine the company had not previously built for aircraft. However, they rose to the challenge and created the J-58, a turbine engine that ran on liquid hydrogen. Because liquid hydrogen is very flammable and difficult to store, the J-58 engines were fuelled in the air. The fuel was pumped through the engine while it was mounted on the aircraft, rather than beforehand. This meant the engines could be fuelled and ready to go quickly. The J-58 engines are so efficient and powerful; they can even operate in a vacuum, albeit at a lower power setting. This is why the SR-71 could fly higher than any other aircraft.

An impossible deadline

The SR-71 was originally intended to be a high-speed reconnaissance aircraft. But by the time it entered service, the world had changed, and the SR-71 found itself with a new mission: to fly above 80,000 feet and capture images of Soviet nuclear missile sites. When the aircraft was originally designed, engineers had not anticipated the need for it to operate at such high altitudes — those altitudes had previously been too high for most aircraft. The Air Force had been flying U-2 reconnaissance aircraft at altitudes above 70,000 feet for several years, but the Soviets were aware of their presence, and sent up MiG fighters to shoot them down. The SR-71 was needed to keep the U-2’s safe. The problem was, the SR-71 had not yet been built and the Air Force had a tight deadline to get a high-altitude spy plane in the air.

A short runway and a even shorter deadline

When the US Air Force started developing the SR-71, they wanted to test the aircraft’s design by seeing how fast it would go. They chose a runway at Edwards Air Force Base in California as the site of their test flights. Air Force officials had decided that the runway length was appropriate for the test, but the officials were unaware that the runway had been lengthened since the original project had been approved. With the runway now longer than expected, the aircraft would simply drop off the end of the runway if it reached the targeted speed of Mach 3. To prevent the test from ending in disaster, engineers devised an ingenious solution. They used a measuring tape to determine the distance between the runway’s touchdown markers and measured the length of the SR-71. Then, they placed pieces of cardboard under the wheels of the aircraft to shorten the distance between the touchdown markers. When the test flight reached Mach 3, the wheels lifted off the ground and the SR-71 floated down the runway.

The final product: A masterpiece of engineering

When the SR-71 was first introduced, it broke the sound barrier in level flight and achieved a speed of Mach 3.3. Furthermore, the aircraft was designed to absorb radar signals, making it invisible to the enemy. Even the paint was specially designed to deflect electromagnetic waves. However, the engines’ dependence on liquid hydrogen proved to be a major flaw. While the SR-71 could “top off” its tanks using a system that transferred hydrogen from the fuel tank, the tanks were not meant to store liquid hydrogen for long periods of time. The SR-71 was being stationed in England with a special squadron, and the Air Force realized that the cooling system for the liquid hydrogen was inadequate for the English climate. The tanks could easily overheat and explode, and after only a few months, the entire squadron was grounded for safety reasons.

Conclusion

The SR-71 was retired from service in 1999 due to cost and the effectiveness of newer spy planes that have since replaced it. However, even with its retirement from active service, the SR-71 remains one of the most well-known military aircraft still in operation today. This is partly due to its popularity with the public. In addition, people are often amazed by the sheer speed and altitude at which the aircraft operated. It is not a stretch to say that the Lockheed SR-71 Blackbird is one of the fastest and highest-flying aircraft in history. It was built by engineers who needed to push the boundaries of what was possible. While the project that produced this legendary aircraft began as, and remained, a failure, the engineers involved were able to transform it into a masterpiece of aviation.