The Blackbird
The SR-71, which earned the unofficial nickname “Blackbird,” originated as a development from the Lockheed A-12 and YF-12A aircraft and served as a long-range strategic reconnaissance aircraft capable of exceeding Mach 3. December 22, 1964, marked the inaugural flight of an SR-71, with the first operational model being delivered to the 4200th (later redesignated as the 9th) Strategic Reconnaissance Wing at Beale Air Force Base, California, in January 1966.
The Blackbird stood in a class entirely its own compared to all preceding aircraft. As Skunk Works’ legendary aircraft designer Kelly Johnson recalled in a fascinating article on Lockheed Martin’s website: “Everything had to be invented. Everything.”
Production of the SR-71 was done at the Skunk Works plant, in Burbank, California, as the photos in this post show [the image were taken in 1965 and show some of the first SR-71 under construction: featured in the pictures are the first B models (957 and 956) under construction with an A-model (955). My dad Richard “Butch“ Sheffield told me that he watched these airplanes under construction at the Skunk Works plant at Burbank].
SR-71 airframes built almost entirely of titanium
The airframe structures were primarily constructed from titanium and various advanced alloys to endure the heat produced during prolonged high-speed flight; indeed, the Blackbirds were engineered to maintain a cruising speed of Mach 3 for over an hour at altitudes reaching 85,000 feet.
Blackbird’s engineers faced a puzzling issue regarding the corrosion of certain titanium components. Nevertheless, they eventually determined the cause. It turned out to be chlorine present in the water!
According to Wisconsin Metal Tech, the SR-71 engineers were among the first people in history to make real use of the material. In that process, they ended up throwing away a lot of material, some through necessity and some through error. At times, the engineers were perplexed as to what was causing problems, but thankfully, they documented and cataloged everything, which helped find trends in their failures.
Spot-welded parts made in summer corroded, while those made in winter didn’t
They discovered that spot-welded parts made in the summer were failing very early in their life, but those welded in winter were fine. They eventually tracked the problem to the fact that the Burbank water treatment facility was adding chlorine to the water they used to clean the parts to prevent algae blooms in summer, but took it out in winter. Chlorine reacts with titanium, so they began using distilled water from this point on.
They discovered that their cadmium-plated tools were leaving trace amounts of cadmium on bolts, which would cause galvanic corrosion and cause the bolts to fail. This discovery led to all cadmium tools being removed from the workshop.
Check out Habubrats SR-71 X profile and Born into the Wilde Blue Yonder Habubrats Facebook for further Blackbird photos and stories.
Lockheed photos via Tony Landis and CIA
