Lockheed Experimental Stealth-Tactical (XST) / Have Blue
Lockheed was one of at least five US aerospace companies which apparently received contracts in 1973 from the US Defense Advanced Projects Research Agency (DARPA) to study signature reduction techniques and their potential application to a manned combat aircraft. The effort was code-named Have Blue.
Lockheed's Advanced Development Projects organisation at Burbank (ADP), more commonly known as 'The Skunk Works', already had practical experience in the design of stealth aircraft; low radar signature had been a significant consideration in the Blackbird family of Mach 3.0 reconnaissance aircraft. But rivals, such as General Dynamics, McDonnell Douglas and Northrop, were the then current manufacturers of fighter aircraft for the US military. Even to this day it has not been officially confirmed that Lockheed was the only Have Blue contractor to be funded as far as the hardware stage of an Experimental Stealth-Tactical (XST) prototype. It seems unlikely. It is known, however, that funding for this and other stealth projects was accelerated in 1977, and that the Lockheed design was airborne from the secluded and top secret Groom Lake airfield, on the Nevada test range in December 1977, flown by ADP chief test pilot Bill Park. Although only half the size of the F-117A, this aircraft's configuration was broadly similar, except for the vertical tail surfaces. Apparently these were individually-mounted and inwardly canted, similar to those of the Blackbird series. The prototype Lockheed stealth aircraft was powered by two General Electric J85 turbojets and used an adapted F-16 fly-by-wire system.
Using special-access, fast-track procedures, the programme developed rapidly, despite the crash of a prototype at Groom Lake on 4 May 1978. After a hard landing which damaged the starboard undercarriage member, Bill Park elected to apply power and climb away in order to assess the damage. Following another abortive approach, he was obliged to eject, but sustained serious injuries and never flew the aircraft again. The landing problem was attributed to faulty fly-by-wire software; Ken Dyson took over as the contractor's chief test pilot. There were at least two other Lockheed prototypes, however, and they were evidently flown with great success against various radars on the Nevada range. Ground test vehicles were sent for radar cross-section measurement on large-scale outdoor ranges, with similarly encouraging results. By the end of 1978, Lockheed had received a USAF contract to develop a full-scale production version. It contained warranties covering the aircraft's range, weapons delivery accuracy and radar cross section.
Both prototypes ultimately crashed, one in May 1978 and the other in 1980, with their pilot’s ejecting.
The wreckage of the two Have Blue aircraft was buried within the Nellis Test Range. One was reportedly buried at the Groom Lake site just south of the hangar complex. Lockheed engineers have since searched for the buried Have Blue with a view to restoring it for display purposes, but despite their best efforts have been unable to locate the wrecked aircraft.