Thorton D. Barnes, used with permission via Facebook
Not many aircraft have breached the Mach 3 barrier, but the short-lived, still-loved A-12 “Oxcart” is one such plane. In fact, the A-12, which started flying in 1963, still holds the record (Mach 3.29 at 90,000 feet) for air-breathing, jet piloted aircraft.
The predecessor to the SR-71 Blackbird, Lockheed’s Skunkworks built the A-12 for the same purpose: strategic, high-altitude reconnaissance. The A-12 was shorter and lighter than the SR-71, but even faster, meant to outrun enemy air defenses and bring back crucial imagery intelligence data. However, the SR-71 featured a considerably longer range, which led to the A-12’s retirement in 1968. (The SR-71, meanwhile, flew until 1999.)
Thornton “TD” D. Barnes worked on the A-12 project at the infamous Area 51 site in Nevada. Today, Barnes is the president of Roadrunners Internationale, an association of Area 51 veterans, and the author of books on Area 51 and the secret work done there.
Barnes recently posted declassified images (originally discovered by The Aviationist) of radar cross section testing on a full-sized wooden mockup of the A-12 inside Area 51. Here, Popular Mechanics shares Barnes’s photos with his permission.
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Area 51 and Groom Lake are seen here, likely sometime in the 1960s. “Our special projects work area was the buildings at the edge of the lake,” Barnes explained on Facebook.
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A-12 Radar Cross-Section Testing
According to Barnes, this is a “full-scale A-12 mock-up in its final external configuration with all-moving rudders on stud fins. A piston-activated ram elevated the pole consisting of three battleship propeller shafts welded together to 50 feet with a rotating head for changing the (radar cross section) view.”
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Reducing a Radar Signature with Salt
Barnes and his fellow engineers worked to hide the A-12’s exhaust plumes from radar. Barnes says they ended up “adding radioactive cesium to the fuel that produced a metallic salt that, when vaporized, had a ver