Have Blue was the forerunner to the classic Lockheed F-117 "Nighthawk", the so-called stealth fighter that was actually a bomber. Have Blue, also constructed by Lockheed, was devised as a proof-of-concept aircraft intended to prove the viability of a stealth-centric aircraft including Fly-By-Wire controlling, stealth body designing and stealth body materials. The result was a wholly unique aircraft in the history of aviation. The Have Blue prototypes mimicked the finalized F-117 in both form and function and provided engineers with the needed data when forging ahead with the Nighthawk product. Two prototypes were built for the program from 1977 to 1978 but both were eventually lost during testing.
At the time of the program's origination, the United States Air Force's (USAF) primary opponent on the global stage remained the Soviet Empire and, with it, its broad network of air defense systems and high-speed interceptors. To bypass this network, it was realized that a supersonic, high-flying platform was no longer a viable option given that Soviet air defenses had advanced much too far. Instead, thought was given to developing a subsonic platform capable of simply flying into and out of said defenses through the use of stealth. Stealth would be accomplished by a peculiar shaping of the aircraft as well as non-afterburning turbojet engines and Radar-Absorbent Materials (RAMs) coating the aircraft's "skin".
Design and development of the aircraft fell to Lockheed's vaunted "Skunk Works" arm and computer programs aided engineers in refining the base concept. The end-product was an arrowhead-shaped aircraft with a faceted fuselage and low-set blended wing mainplanes. No horizontal tailplanes were used - instead, inward-canted planes became the only vertical surfaces to be featured. Structural dimensions included a length of 47.2 feet, a wingspan of 22.5 feet and a height of 7.5 feet. Empty weight was 8,950lb against an MTOW of 12,500lb. A conventional wheeled/retractable tricycle undercarriage was featured for ground running.
Internally, the aircraft carried one pilot under a framed, triangular-shaped canopy and position just aft of the sharp nosecone assembly. Propulsion power was served from 2 x General Electric J85-GE-4A non-afterburning turbojet engines and these provided the aircraft with a maximum speed of 600 miles per hour. The exhaust ports of the engines were purposefully designed and aided in reducing the heat signature of the aircraft, particularly from the rear. The fuselage and wings were extended beyond these ports for the same reason and the intakes were shrouded with grille-like panels.
While the Have Blue demonstrator aircraft exhibited roughly the same faceted shaping and planform of the F-117, it was dimensionally smaller than the finalized Nighthawk bomber in USAF service and the vertical tailplanes of the F-117 were outward-canted as this was eventually found to provide better stability. So low was the hope that these diamond-shaped aircraft would realistically fly that the design came to be known as the "Hopeless Diamond" by engineers.
Two prototypes were ultimately constructed for the Have Blue program and these actively flown as "HB1001" and "HB1002" (under complete secrecy). HB1001 went airborne for the first time on December 1st, 1977 and particular attention was paid by engineers to the Fly-By-Wire (FBW) (quadruple redundant) system at play - the Have Blue concept was essentially inherently unstable as aircraft went so external pilot-assistance became mandatory. On May 4th, 1978, on the aircraft's 36th flight, the prototype suffered a hard landing which damaged one of the main undercarriage legs. A lack of fuel then caused a flameout of one of the engines. Unable to land, the test pilot ejected to safety and the prototype crashed.
HB1002, with a revised rear fuselage section, went into the air for the first time on July 20th, 1978. However, its time in the skies was also short-lived for, on July 11th, 1979, a hydraulic leak sparked an engine fire and loss of hydraulic pressure. Again the test pilot ejected to safety but the prototype was lost in the ensuing crash.
Even with the loss of both Have Blue prototypes during testing, the project was still considered a success in the eyes of program observers and nevertheless supplied the needed framework for the F-117 to follow. The press was already somewhat aware that something was afoot by the time of the late 1970s but it was not until the F-117's complete unveiling in 1988 when the concept of a stealth-minded fighter became truly realized to the public. Before long, the idea of a largely faceted fuselage was dropped as computer testing showed curves could be applied and still maintain stealth - which is why the B-2 was able to be finalized with its smooth contours.
Today, the Lockheed F-22 Raptor fighter and F-35 Lightning II strike platform both benefit from the technological breakthroughs offered by the Have Blue program. Of note are the type's combination of faceted surfaces as well as rounded contours.