On May 1, 1960, a Lockheed U-2 reconnaissance aircraft known as the "Dragon Lady" was shot down by a SA-2 surface-to-air missile near Yekaterinburg, soviet Union. The CIA was discredited in the ensuing public opinion war, and then-President Dwight Eisenhower announced the termination of the U-2 program to fly over soviet airspace.
The United States ostensibly terminated reconnaissance operations, but secretly put pressure on the CIA and Lockheed.
"The world of martial arts, only fast is not broken"
Lockheed's aeronautical engineers decided to compensate for the "stealth" deficit with speed, and their answer was: hypersonic reconnaissance aircraft, faster than all the fastest missiles and fighters in the world at the time.
The SR-71 Blackbird was born against this background, with a speed of 3,540 kilometers per hour. To achieve this goal, Lockheed applied a number of new technologies, such as semi-ramjet engines, titanium alloy fuselages, and low detectability. Even its fuel is dedicated, and engineers have developed JP-7 fuel specifically for it.
The titanium raw material for making the SR-71 came from the "nemesis" of the former Soviet Union
The SR-71 body is made of titanium, and the former Soviet Union was the largest producer of titanium at that time. Lockheed went to great lengths to procure enough titanium from Maozi. They do a lot of fake business through third world countries, shipping titanium raw materials from the former Soviet Union to the United States.
Interestingly, the upper limit of an aircraft's speed is not determined by the fuselage, but by the engine. The SR-71 is powered by two Pratt & Whitney J58-1 variable-cycle ramjet turbojet engines with a temperature detector in front of the engine, which indicates that the aircraft can no longer accelerate when the detected temperature exceeds 427 degrees Celsius. Pu Hui, who is responsible for building the engine, said that when the detection temperature exceeds the standard, they cannot guarantee that the engine will still work properly.
John Kelly, the chief designer of the SR-71, found that when the surface temperature of the aircraft exceeded 300 degrees Celsius, the temperature of the leading edge of the aircraft was similar to that of it, and the temperature of the rest of the aircraft could reach 200 degrees Celsius. The 36 tons of fuel carried by the six main fuel tanks can also reach a temperature of 190 degrees Celsius, which is prone to explosions and fires.
So engineers had to develop a fuel with a high flash point, the JP-7. A pilot once threw a cigarette butt into JP-7 fuel, and then the cigarette butt went out.
Since the body of SR-71 is mainly made of titanium alloy, this material is very difficult to weld, so it also uses riveting. The SR-71 is about 1 foot longer than the cold aircraft when flowing. The riveting process is always accompanied by oil leakage problems due to the effect of thermal expansion and contraction, resulting in SR-71 always being accompanied by oil leakage.
The SR-71 was refueled only after receiving the mission order, and it was also filled with half a tank of fuel, leaking while adding, leaving about 450 kilograms of fuel on the ground after being added. This also made the takeoff process for the SR-71 lengthy, taking 40 minutes at a time. After the SR-71 completes its mission, it also needs to do a comprehensive inspection, which takes another 19 hours. As a result, the number of SR-71s built was reduced again and again, and only 32 were eventually rolled off the production line.
Typically, the average mission time for the SR-71 is 3.5 to 4 hours, while the ultra-long mission is up to 8 hours, which requires aerial refueling. During the 1973 Yom Kippur War, pilots took off from the East Coast, flew to the Middle East, took pictures, and turned back. The President of the United States saw the intelligence photos taken before deciding to end the war.
In the early days of the SR-71's replacement of the U-2, other aircraft, including missiles, were only expected to sigh. However, with the service of the 5-speed SA-5 surface-to-air missile and the 3-sonic MiG-25 interceptor, the speed advantage of the SR-71 was in vain. In order not to repeat the mistake of the U-2 being shot down and the pilot being captured. The SR-71 is only used in Vietnam, the Middle East, and North Korea.
The Vietnamese battlefield became the site of SR-71 training, when the SR-71 was deployed at Kadena base, it took off with only 1/3 of the fuel, and then ordered tankers carrying JP-7 fuel to stand in the air. After waiting for the "Blackbird" to fly for half an hour to warm up, it is filled with fuel tanks in the form of aerial refueling.
During the Fourth Middle East War, the SR-71 traveled to the Middle East and conducted dust sampling missions over Israeli airspace. During this time, Israeli F-4 fighters took off to intercept and launch Sidewinder missiles.
The SR-71 also conducted reconnaissance operations against North Korea, but all of them flew at Mach 3. Later, after North Korea imported SA-5 anti-aircraft missiles, the SR-71 stopped operating against North Korea.
Thereafter, the SR-71 also conducted a "Baltic Chase" along the Soviet border. The Baltic Sea is surrounded by the borders of Sweden, Finland, the Soviet Union and Poland. The SR-71 approached the Soviet Union from the high seas of the Baltic Sea, at which point the Soviets would also send MiG-25s to intercept them. The two sides basically flew along the border. This phenomenon continued until the withdrawal of SR-71 from the UK in 1988.
With the popularity of reconnaissance satellites, the SR-71 was fully retired from active service in 1998. A new record of not being shot down during the SR-71's service.