The Lockheed SR-71 "Blackbird" is a long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft designed and produced by Lockheed Corporation in the United States. The United States Air Force (USAF) and NASA both operated it.
The Making
Titanium was mainly employed only in components exposed to the greatest temperatures, such as exhaust fairings and the leading edges of wings, on most aircraft due to the expense involved. On the SR-71, titanium made up 85 percent of the construction, with polymer composite materials making up the balance. Lockheed employed a more readily worked titanium alloy that softened at a lower temperature to save money. Because of the difficulties, Lockheed developed new fabrication technologies that have subsequently been employed in the production of other aircraft. Lockheed discovered that cleaning welded titanium needed distilled water since tap water contains chlorine, which is corrosive; cadmium-plated tools could not be used because they corroded as well. Another issue was metallurgical contamination; at one time, 80 percent of the titanium shipped for manufacturing was rejected due to this.
Titanium Extraction
Because titanium was in scarce supply in the United States, the Skunk Works crew had to hunt for it overseas. The Soviet Union supplied much of the required materials. Colonel Rich Graham, an SR-71 pilot, explained how the plane was acquired: Inside and exterior, the plane is made of 92 percent titanium. The United States did not have the ore sources — rutile ore – while they were manufacturing the airplane. It's extremely sandy soil that can only be found in a few places on the planet. The USSR was the primary ore supply. They were able to transport the rutile ore to the US to create the SR-71 by working via Third World countries and fraudulent companies.
Shape and threat avoidance
Chines were a pair of sharp edges that ran down the fuselage from each side of the nose of the SR-71. Frank Rodgers, a doctor with the Scientific Engineering Institute, a CIA front organization, discovered that a cross-section of a sphere had a far lower radar reflection, therefore he designed a cylindrical-shaped fuselage with sides that extended outward. After the advisory panel temporarily chose Convair's FISH design over the A-3 based on RCS, Lockheed adopted chines for its A-4 through A-6 designs.
Aerodynamicists found that the chines created powerful vortices and contributed lift, resulting in unexpected aerodynamic improvements. The angle of incidence of the delta wings might be reduced to improve stability and reduce drag at high speeds, as well as carry additional weight, such as fuel. The chines' vortices created turbulent flow over the wings at high angles of attack, slowing landing speeds and making stalling more difficult. The Chinese also increased the agility of aircraft such as the F-5, F-16, F/A-18, MiG-29, and Su-27 by acting as leading-edge extensions. The removal of the canard foreplanes was also made possible by the insertion of chines.
Cold War Operatives
There were two routes. One was along the Norwegian west coast and along the Kola Peninsula, where the Soviet Navy's Northern Fleet had numerous substantial naval stations. The Baltic Express was the alternative line, which ran from Mildenhall over the Baltic Sea. One of the engines on an SR-71 that was on a mission near the Baltic Sea to spy on Soviet troops burst on June 29, 1987. A MiG-25 had locked a missile on the damaged SR-71, but no missiles were launched since the plane was being escorted. The four Swedish pilots engaged received medals from the US Air Force on November 29, 2018.
Examination
The reactivation was greeted with opposition. The aircraft had not been budgeted for by the US Air Force. The funding was reauthorized by Congress, but President Bill Clinton sought to use his line-item veto in October 1997 to eliminate the $39 million budgeted for the SR-71. The line-item veto was declared illegal by the United States Supreme Court in June 1998. All of this put the SR-71's future in jeopardy until September 1998, when the USAF requested that money be transferred; the SR-71 was finally retired in 1998. The final two operational Blackbirds were operated by NASA until 1999. Except for two SR-71s and a few D-21 drones kept by the Armstrong Flight Research Center, all other Blackbirds have been transported to museums.
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