History of the SR-71

The US was in need of a new spy plane, and the SR-71 was the answer.

A t Lockheed’s advanced development group, Skunk Works® in Burbank, work had already begun on an innovative aircraft with improved intelligence-gathering, one that would fly faster than any aircraft had ever before or since, at greater altitude, and with a minimal radar cross section.  President Eisenhower deeply valued the strategic benefits of the U-2’s airborne reconnaissance during tense Cold War times.  And now the call came from Lockheed’s customer in Washington to build the impossible – an aircraft that can’t be shot down – and do it fast.

First Flight

On December 22nd, 1964, the SR-71 took off for the first time

Materials

The very first Blackbird was built using Soviet titanium that the CIA smuggled into the US, making it the ultimate spy machine.

Conspiracy… conspiracy…

The first testing location? Area 51.

Requirements

To fly or even work on the plane, every pilot was required to be married

Overheating

At Mach 3, some parts of the plane could reach 1,000 degrees (F), that’s the reason for the special dark navy blue paint it would cool the plane down.

A suit built for space

The flight suit was essentially built for space, and looks like one built for NASA. They also had to have specially made watches, because the standard one would freeze being that high in our atmosphere.

unbroken speed records

On her final flight, the Blackbird, destined for the Smithsonian National Air and Space Museum , sped from Los Angeles to Washington in 64 minutes, averaging 2,145 mph and setting four speed records.

Everything Had to be Invented

K elly Johnson, one of the preeminent aircraft designers of the twentieth century, and his Skunk Works team had a track record of delivering “impossible” technologies on incredibly short, strategically critical deadlines.  The U-2 was but one example.  The group was known for its unfailing sense of duty, its creativity in the face of a technological challenge and its undaunted perseverance.

This new aircraft was in a different category from anything that had come before. “Everything had to be invented. Everything,” Johnson recalled. He committed Skunk Works to succeed in its toughest assignment to date: to have the innovative, challenging, envelope-bursting aircraft flying in a mere twenty months.

The speed of the new aircraft was to exceed 2,000 mph. Other planes of the era could, in theory, approximate that speed but only in short, after-burner-driven bursts. This new plane needed to maintain a record-setting speed for hours at a time. At such velocity, friction with the atmosphere generates temperatures that would melt the conventional airframe.

With anticipated temperatures on the aircraft’s leading edges exceeding 1,000 degrees Fahrenheit, dealing with the heat raised a host of seemingly insurmountable design and material challenges. Titanium alloy was the only option for the airframe —providing the strength of stainless steel, a relatively light weight, and durability at the excessive temperatures.

A Stealthy Pioneer

R educing the size of the Blackbird’s radar image meant an even further reduction in the likelihood that the plane would be perceived and shot down. Though the initial test results were good, rumors of Soviet radar advances led the U.S. government to ask for an even smaller radar profile.

Surfaces had to be redesigned to avoid reflecting radar signals, the engines moved to a subtler mid-wing position, and a radar-absorbing element was added to the paint. Then a full-scale model of the Blackbird was hoisted on a pylon for radar testing at a Skunk Works’ secret location in the Nevada desert. With tests carefully scheduled to avoid Soviet satellite observations, the results were impressive: The Blackbird model, more than 100 feet in length, would appear on Soviet radar as bigger than a bird but smaller than a man. The team had succeeded in reducing radar cross section by 90 percent.

Titanium, however, proved to be a particularly sensitive material from which to build an airplane. The brittle alloy shattered if mishandled, which meant great frustration on the Skunk Works assembly line, and new training classes for Lockheed’s machinists. Conventional cadmium-plated steel tools, it was soon learned, embrittled the titanium on contact; so new tools were designed and fabricated—out of titanium.

While friction would generate incredible heat at the leading edges of the aircraft, the ambient temperature outside the cockpit window would be -60 degrees Fahrenheit. Skunk Works’ Ben Rich spent untold hours tackling the problem of how heat could be dissipated across the entire airframe. Then he recalled a simple lesson from one of his university courses: Black paint both emits and absorbs heat. The aircraft was painted black, and soon earned its name: “Blackbird.”

The original Blackbird was the A-12 and made its first flight on April 30, 1962. The single-seat A-12 soon evolved into the larger SR-71, which added a second seat for a Reconnaissance Systems Officer and carried more fuel than the A-12. The SR-71’s first flight was on December 22, 1964.

The SR-71 Rose To The Challenge

T he pressure mounted to deliver the Blackbird to service on October 27, 1962 when, at the height of the Cuban missile crisis, Air Force Major Rudolph Anderson was piloting a U-2 reconnaissance mission over Cuba and suffered a fatal injury from a Soviet surface-to-air strike. The need for a faster, stealthier spy plane was crucial for the United States during this vital point in the Cold War.

Skunk Works responded, diligently and creatively persisting through the many problems that arose as flight testing pushed the envelope. Breaking records nearly every time it flew, the Blackbird achieved a sustained speed above Mach 3 on July 20, 1963, at an astounding altitude of 78,000 feet. The challenges kept coming: Zipping across the sky at 3,000 feet per second, the rules of navigation needed be rewritten. Visual references for conventional flying—highways, rivers, and metropolitan areas—were rendered obsolete, giving way to mountain ranges, coast lines, and large bodies of water.

Piloting the Blackbird was an unforgiving endeavor, demanding total concentration. But pilots were giddy with their complex, adrenaline-fueled responsibilities. “At 85,000 feet and Mach 3, it was almost a religious experience,” said Air Force Colonel Jim Wadkins. “Nothing had prepared me to fly that fast… My God, even now, I get goose bumps remembering. ”

At that speed and altitude, even the best air defense systems had no hope of catching the Blackbird. When anti-aircraft weapons were fired, a warning light glowed red on the control panel. But that would typically be the last the pilot would see of the attempted attack, as surface-to-air missiles consistently missed wildly, exploding many miles from the intended target.

The records set are many: The Blackbird was and remains the world’s fastest and highest-flying manned aircraft. On its retirement flight from Los Angeles to Washington in 1990, to its final resting place in the Smithsonian Air & Space collection, the plane flew coast to coast in 67 minutes.

Most importantly, the aircraft delivered on its strategic responsibilities, providing the United States detailed, mission-critical reconnaissance for more than two decades. Only a select few know the true extent of the role the Blackbird’s intelligence played in the Cold War. But its legacy as a game-changer will be admired for generations.

Text © 2018 Lockheed Martin Corporation. All Rights Reserved.