By the mid-1970s the problem was simple to state. Soviet air defenses had become good enough that aircraft flying into them were not expected to come back. The Defense Advanced Research Projects Agency asked industry whether an aircraft could be made so hard to see on radar that it would not matter.
Lockheed’s Skunk Works joined the competition late. Its answer came from a mathematician named Denys Overholser and a paper published in Moscow in 1962 by the Soviet physicist Pyotr Ufimtsev, which described how to predict the way radar waves scatter from the edges of a flat surface. The Air Force’s Foreign Technology Division had translated it in 1971. It was, in effect, available to anyone.
The method had a limit. The computers of the day could only calculate reflections from flat panels, so the aircraft would have to be built from flat panels. The result, a faceted shape the engineers called the Hopeless Diamond, looked nothing like an aircraft and was not obviously capable of flight.
“Our old D-21 drone has a lower radar cross-section than that goddamn diamond.”
A model was mounted on a pole on a radar range. Johnson was wrong. He paid Ben Rich, who ran the Skunk Works, a quarter.
§ 01Borrowed parts
Two flying demonstrators were ordered under the name HAVE BLUE. To save time and money they were assembled largely from parts already in the inventory: engines from the T-2 Buckeye trainer, a fly-by-wire flight control system from the F-16. The finished aircraft was 47 feet 3 inches long, with a wingspan of 22 feet 6 inches and two inward-canted tails.
It was painted in a three-tone camouflage — not to hide it from radar, which it managed on its own, but to stop people on the ground from noticing the facets.
§ 02Groom Lake
HB1001 first flew on 1 December 1977 at Groom Lake, Nevada, with Lockheed test pilot Bill Park at the controls. On 4 May 1978, on its thirty-sixth flight, it landed hard, Park was ordered to climb away and eject, and he was seriously injured.
HB1002, flown by Air Force test pilot Ken Dyson, carried on with the radar trials against which every later stealth aircraft would be measured. It was lost on 11 July 1979, on its fifty-second flight, after a fire. Dyson ejected safely.
The wreckage of both aircraft was buried on the Nevada ranges. The program had already done what it was for. In November 1978, before the second crash, the Air Force had ordered the aircraft that became the F-117 Nighthawk. Its existence was acknowledged ten years later, on 10 November 1988.
