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Have Blue

Lockheed Skunk Works · Stealth demonstrator · Cold War (1970–1991)

The Lockheed Have Blue was an American experimental stealth-aircraft prototype — the proof-of-concept demonstrator that established stealth technology + led directly to the F-117 Nighthawk. Lockheed Skunk Works' Bill Schroeder + Denys Overholser designed the Have Blue in 1975-1977 under a classified DARPA contract; first flight 1 December 1977. Only 2 Have Blue prototypes were built. Both crashed during testing (HB1001 in May 1978, HB1002 in July 1979). The programme directly seeded the F-117 Nighthawk in production from 1981.

The Have Blue used 2 × General Electric J85-GE-4A turbojet engines (2,950 lbf each, mounted close to the fuselage in shielded buried inlets). Maximum speed Mach 0.81 (subsonic), service ceiling 11,000 m. Crew: 1. The aircraft used the faceted-surface stealth approach developed by Lockheed mathematician Denys Overholser based on Soviet physicist Pyotr Ufimtsev's 1962 paper on edge-diffraction theory ("Method of Edges in the Theory of Diffraction") — angles + flat surfaces designed to scatter radar energy away from the source. The Have Blue's radar cross-section was approximately 1/1000 of a conventional fighter — an order of magnitude lower than any prior aircraft.

Have Blue's two prototypes both crashed during testing — but flight test data validated the faceted-stealth approach. Lockheed Skunk Works followed Have Blue with the F-117 Nighthawk full-scale production design (first flight 18 June 1981, IOC 1983, retirement 2008) — first deployed in combat over Panama 1989 + Iraq 1991. The Have Blue programme was declassified in the late 1990s. About 0 Have Blue airframes survive (both crashed); reconstructed engineering drawings + photographs exist.

For Kids — a shorter, friendlier version

The Lockheed Have Blue was a secret American test plane. It was built to prove that a plane could hide from radar. Engineers at Lockheed Skunk Works designed it in the 1970s. Its first flight was on December 1, 1977.

The Have Blue looked very strange. It was covered in flat, angled surfaces instead of smooth curves. Those flat surfaces bounced radar signals away. This made the plane nearly invisible to radar. It was smaller than a typical fighter jet of its time.

Only two Have Blue planes were ever built. Both of them crashed during test flights. The pilots survived both crashes. Even so, the tests taught engineers a huge amount about stealth flying.

The Have Blue used two jet engines buried inside its body. This helped hide the plane from radar even more. It could fly at just under the speed of sound. One pilot flew the plane at a time.

The Have Blue led directly to the F-117 Nighthawk. The F-117 became the world's first stealth jet to go into full service. Without the Have Blue, stealth aircraft might never have been built.

Fun Facts

The Have Blue had a radar return smaller than a large bird — about one-thousandth the size of a normal fighter jet's radar signal.
Only two Have Blue prototypes were ever built, and both of them crashed during testing.
The plane's flat, angled surfaces were inspired by math from a Soviet scientist's paper written in 1962.
The Have Blue's first flight took place on December 1, 1977.
The Have Blue was smaller than a typical fighter jet, making it even harder to spot.
Both pilots survived their crashes, which helped engineers learn from the accidents.
The Have Blue flew at just under the speed of sound, slower than most jet fighters.
The Have Blue led directly to the F-117 Nighthawk, which entered service in 1981.

Kids’ Questions

What made the Have Blue so hard to see on radar?

The Have Blue was covered in flat, angled panels instead of smooth curves. Those flat surfaces bounced radar signals away from the radar dish. This made the plane nearly invisible to radar systems. Its engines were buried inside the body to hide them too.

Did both test planes crash?

Yes, both Have Blue prototypes crashed during test flights. The first crashed in May 1978 and the second in July 1979. Both pilots survived. Engineers still learned a great deal from the tests.

How did the Have Blue lead to other planes?

The Have Blue proved that stealth technology really worked. Engineers used what they learned to build the F-117 Nighthawk. The F-117 became the world's first stealth plane in full service, starting in 1981.

Variants

Have Blue HB1001 + HB1002 (only prototypes): Two prototypes. Both crashed during testing.

Notable Operators

Lockheed Skunk Works + DARPA (test programme only): Classified test programme 1977-1979.

Frequently Asked Questions

Why is the Have Blue famous?

Foundational stealth aircraft. The Have Blue proved (1977-1979) that faceted-surface design could reduce aircraft radar cross-section by 1000× — enabling penetration of heavily-defended airspace without detection. This proof-of-concept directly seeded the F-117 Nighthawk + B-2 Spirit + F-22 Raptor + F-35 Lightning II stealth-aircraft generations. The Have Blue's two prototypes both crashed during testing — yet the test data validated the concept, demonstrating that early stealth flight could be achieved despite handling challenges (faceted-surface aircraft have poor inherent stability requiring fly-by-wire control).

Sources

Wikipedia — Lockheed Have Blue