Lockheed Have Blue was the code name for Lockheed

Lockheed Corporation

The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...

's "proof of concept

Proof of concept

A proof of concept or a proof of principle is a realization of a certain method or idea to demonstrate its feasibility, or a demonstration in principle, whose purpose is to verify that some concept or theory that has the potential of being used...

" (i.e. demonstrator) that preceded the F-117 Nighthawk production stealth aircraft

Stealth aircraft

Stealth aircraft are aircraft that use stealth technology to avoid detection by employing a combination of features to interfere with radar as well as reduce visibility in the infrared, visual, audio, and radio frequency spectrum. Development of stealth technology likely began in Germany during...

. Have Blue was designed by Lockheed's Skunk Works

Skunk works

Skunk Works is an official alias for Lockheed Martin’s Advanced Development Programs , formerly called Lockheed Advanced Development Projects. Skunk Works is responsible for a number of famous aircraft designs, including the U-2, the SR-71 Blackbird, the F-117 Nighthawk, and the F-22 Raptor...

 division, and tested at Groom Lake

Groom Lake

Groom Lake is a salt flat in Nevada used for runways of the Nellis Bombing Range Test Site airport on the north of the Area 51 USAF military installation. The lake at elevation is ~ from north to south and from east to west at its widest point...

, Nevada

Nevada

Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...

. The Have Blue was the first fixed-wing aircraft

Fixed-wing aircraft

A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...

 designed from an electrical engineering

Electrical engineering

Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...

 (rather than an aerospace engineering) perspective. The aircraft's plate-like, faceted shape was designed to deflect electromagnetic waves

Electromagnetic radiation

Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...

, greatly reducing its radar

Radar

Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 signature. Two flyable vehicles were constructed, but both crashed during the flight-test program.

In the 1970s, it became increasingly apparent to U.S. planners that, in a military confrontation with Warsaw Pact

Warsaw Pact

The Warsaw Treaty Organization of Friendship, Cooperation, and Mutual Assistance , or more commonly referred to as the Warsaw Pact, was a mutual defense treaty subscribed to by eight communist states in Eastern Europe...

 forces, NATO aircraft would quickly be decimated. This came as a result of sophisticated Soviet defense networks, which used surveillance radars and radar-guided surface-to-air missile

Surface-to-air missile

A surface-to-air missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft or other missiles...

s (SAM) and anti-aircraft artillery to seek and eliminate enemy aircraft. Consequently, the Defense Advanced Research Project Agency (DARPA) started a study on low-observability aircraft, seeking to design and produce an operational stealth aircraft. Five companies were initially invited, three of which bowed out early. The remaining two were later joined by Lockheed.

To design the aircraft, the Skunk Works' design team devised a computer program

Computer program

A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

 to calculate the radar cross-sections (RCS) of various designs. The eventual design characteristically featured faceted surfaces to deflect radar waves elsewhere. It had highly-swept wings

Swept wing

A swept wing is a wing planform favored for high subsonic jet speeds first investigated by Germany during the Second World War. Since the introduction of the MiG-15 and North American F-86 which demonstrated a decisive superiority over the slower first generation of straight-wing jet fighters...

 and inward-canted vertical stabilizer

Vertical stabilizer

The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...

s, which lead to its being nicknamed "Hopeless Diamond". The first operational aircraft made its maiden flight

Maiden flight

The maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. This is similar to a ship's maiden voyage....

 on 1 December 1977. The flight test program validated the feasibility of a flyable stealth aircraft. However, both prototypes were lost due to mechanical problems. Nevertheless, Have Blue was deemed a success, paving the way for the first operational stealth aircraft, Senior Trend, or F-117 Nighthawk.

Origins

The Lockheed Have Blue was born out of a requirement to evade radar detection. During the Vietnam War

Vietnam War

The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

, radar-guided surface-to-air missile

Surface-to-air missile

A surface-to-air missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft or other missiles...

s (SAM) and anti-aircraft artillery (AAA) posed a significant threat to US aircraft. As such, strike aircraft during the war often required support aircraft to perform combat air patrols and suppression of enemy air defenses (SEAD). The 1973 Yom Kippur War

Yom Kippur War

The Yom Kippur War, Ramadan War or October War , also known as the 1973 Arab-Israeli War and the Fourth Arab-Israeli War, was fought from October 6 to 25, 1973, between Israel and a coalition of Arab states led by Egypt and Syria...

 again highlighted the vulnerability of aircraft to SAMs – the Israeli Air Force

Israeli Air Force

The Israeli Air Force is the air force of the State of Israel and the aerial arm of the Israel Defense Forces. It was founded on May 28, 1948, shortly after the Israeli Declaration of Independence...

 lost 109 aircraft in 18 days. During the Cold War

Cold War

The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

, the Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 developed an integrated defense network, central to which were medium- to long-range surveillance radars. SAMs and AAA batteries would be set up around key locations to defend them from incoming enemy aircraft. If the loss ratio of Israel during the Yom Kupper War was experienced by NATO forces during a military confrontation with the Warsaw Pact

Warsaw Pact

The Warsaw Treaty Organization of Friendship, Cooperation, and Mutual Assistance , or more commonly referred to as the Warsaw Pact, was a mutual defense treaty subscribed to by eight communist states in Eastern Europe...

, NATO aircraft numbers would be depleted within two weeks.

In 1974, DARPA secretly requested answers from five aircraft manufacturers regarding two considerations. The first was about the signature thresholds at which an aircraft is virtually undetectable. The second point was whether these companies had the capacity to design and manufacture such an aircraft. Fairchild and Grumman declined to participate, while General Dynamics

General Dynamics

General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...

 insisted on the use of electronic countermeasures

Electronic countermeasures

An electronic countermeasure is an electrical or electronic device designed to trick or deceive radar, sonar or other detection systems, like infrared or lasers. It may be used both offensively and defensively to deny targeting information to an enemy...

. As a result, General Dynamics left the discussion. The remaining two companies, McDonnell Douglas

McDonnell Douglas

McDonnell Douglas was a major American aerospace manufacturer and defense contractor, producing a number of famous commercial and military aircraft. It formed from a merger of McDonnell Aircraft and Douglas Aircraft in 1967. McDonnell Douglas was based at Lambert-St. Louis International Airport...

 and Northrop

Northrop Corporation

Northrop Corporation was a leading United States aircraft manufacturer from its formation in 1939 until its merger with Grumman to form Northrop Grumman in 1994. The company is known for its development of the flying wing design, although only a few of these have entered service.-History:Jack...

, were each awarded $100,000 for further research.

Design effort and early testing

Lockheed, having been absent from the fighter aircraft industry for 10 years, was not approached by DARPA in 1974. Ed Martin, Lockheed California Companies director of science and engineering, became aware of the research into stealth during his work at the Pentagon

The Pentagon

The Pentagon is the headquarters of the United States Department of Defense, located in Arlington County, Virginia. As a symbol of the U.S. military, "the Pentagon" is often used metonymically to refer to the Department of Defense rather than the building itself.Designed by the American architect...

 and Wright-Patterson AFB. Martin and Ben Rich

Ben Rich

Benjamin Robert Rich was the second director of Lockheed's Skunk Works from 1975 to 1991, succeeding its founder, Kelly Johnson. Regarded as the "father of stealth," Ben Rich was responsible for leading the development of the F-117, the first production stealth aircraft...

, who at that time had recently become Skunk Works

Skunk works

Skunk Works is an official alias for Lockheed Martin’s Advanced Development Programs , formerly called Lockheed Advanced Development Projects. Skunk Works is responsible for a number of famous aircraft designs, including the U-2, the SR-71 Blackbird, the F-117 Nighthawk, and the F-22 Raptor...

' president, briefed Clarence "Kelly" Johnson on the program. The Central Intelligence Agency

Central Intelligence Agency

The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

 (CIA) gave Skunk Works permission to discuss with DARPA on the stealth characteristics of the A-12 and D-21

Lockheed D-21/M-21

The Lockheed D-21 was an American Mach 3+ reconnaissance drone. The D-21 was initially designed to be launched from the back of its M-21 carrier aircraft, a variant of the Lockheed A-12 aircraft. Development began in October 1962...

. Rich and Martin formally requested DARPA for the company to participate in the program, but the agency initially refused because there were insufficient funds; after much debate, Lockheed was allowed entry, albeit without a government contract.
Preliminary designer Dick Scherrer

Richard C. Scherrer

Richard C. Sherrer is an aircraft designer notable for pioneering work on revolutionary aircraft designs with extremely low radar cross sections that led to the Lockheed F-117 Nighthawk and Northrop Grumman B-2 Spirit.-Career:...

 requested possible shapes upon which he could base his low radar cross-section (RCS) design. He was introduced to Denys Overholser, who recommended an aircraft with flat surfaces. Overholser later recounted his discussion with Sherrer: 'When Dick Scherrer asked me... I said "Well, it's simple, you just make it out of flat surfaces, and tilt those flat surfaces over, sweeping the edges away from the radar view angle, and that way you basically cause the energy to reflect away from the radar."' Scherror subsequently drew a preliminary low-RCS aircraft with faceted surfaces. At the same time, Overholser hired mathematician Bill Schroeder, with whom he had a prior working relationship – in fact, it was Schroeder who trained Overholser on mathematics relating to stealth aircraft. Kenneth Watson was hired as the senior lead aircraft designer.

During the next few weeks, the team created a computer program which could evaluate the RCS of possible designs. The RCS-prediction software was called "ECHO 1". As tests with the program proceeded, it became apparent that edge calculations by the program were incorrect due to diffraction

Diffraction

Diffraction refers to various phenomena which occur when a wave encounters an obstacle. Italian scientist Francesco Maria Grimaldi coined the word "diffraction" and was the first to record accurate observations of the phenomenon in 1665...

. In 1964, Pyotr Ufimtsev, the chief scientist of the Moscow Institute for Radio Engineering, published a seminal paper titled Method of Edge Waves in the Physical Theory of Diffraction. The work was translated by the Air Force Systems Command

Air Force Systems Command

Air Force Systems Command is a former United States Air Force command. Its headquarters was located at Andrews Air Force Base, Maryland...

's Foreign Technnology Division; subsequently, Overholser incorporated elements of Ufimtsev's work to refine the software. ECHO 1 allowed the team to quickly decide which of the 20 possible designs were optimal, finally settling on the faceted delta-wing design. However, many within the division were skeptical of the shape, giving rise to the name "Hopeless Diamond" – Kelly Johnson said to Rich, "Our old D-21 drone has a lower radar cross-section than that goddamn diamond".

For early tests of the design, two ⅓-scale wooden mock-ups were constructed. One model, coated in metal foil, was used to verify ECHO 1's RCS calculations, while the other was earmarked for wind tunnel tests. Afterwards, a model was moved to the Grey Butte Range radar-testing facility in the Mojave Desert

Mojave Desert

The Mojave Desert occupies a significant portion of southeastern California and smaller parts of central California, southern Nevada, southwestern Utah and northwestern Arizona, in the United States...

 near Palmdale, which allowed more accurate tests of the aircraft's RCS. In the event, the aircraft's RCS level confirmed ECHO 1's predictions. This meant Ben Rich won a quarter

Quarter (United States coin)

A quarter dollar, commonly shortened to quarter, is a coin worth ¼ of a United States dollar, or 25 cents. The quarter has been produced since 1796. The choice of 25¢ as a denomination, as opposed to 20¢ which is more common in other parts of the world, originated with the practice of dividing...

 from Johnson, who previously insisted that the D-21 had less RCS than Have Blue.

Experimental Survival Testbed

In the summer of 1975, DARPA informally invited Lockheed, Northrop and McDonnell Douglas to develop an aircraft under the name "Experimental Survival Testbed" (XST). McDonnell Douglas, having identified the thresholds at which aircraft were deemed undetectable, was unable to design and produce such an aircraft. Phase 1 of XST would see both Lockheed and Northrop build full-scale models to test their RCS, construct flyable vehicles, and wind-tunnel test their designs. Following Phase 1, a sole contractor would be selected to continue with the construction and flight testing of two demonstrators as part of Phase 2. Northrop's and Lockheed's designs were generally similar, though the former's submission featured more angular and flat surfaces. The company used "GENSCAT", a software similar to ECHO 1, to calculate the RCS of its designs.

On 1 November 1977, Lockheed and Northrop were each awarded $1.5-million contracts to proceed with Phase 1 of XST. During a four-month period, the two companies were each required to construct full-scale wooden mock-ups, which would then be evaluated at the USAF's Radar Target Scatter

National Radar Cross-section Facility

The United States' National Radar Cross-section Facility is located at Holloman AFB, New Mexico.-References:*...

 (RATSCAT) test facility at White Sands, New Mexico

White Sands, New Mexico

White Sands is a census-designated place in Doña Ana County, New Mexico, United States. The population was 1,323 at the 2000 census. It is part of the Las Cruces Metropolitan Statistical Area...

. To test the design's radar returns, Lockheed erected a $187,000 specially built pole upon which the model would be perched. In March 1976, a Lockheed model was transferred to the range before being tested; the following month Lockheed was pronounced the winner. DARPA, having realized the progress accumulated throughout the study, urged the Northrop team to remain together. The agency would later initiate the Battlefield Surveillance Aircraft, Experimental (BSAX), which evolved into the Tacit Blue

Northrop Tacit Blue

|-See also:...

 and, ultimately, the B-2 bomber.

Construction and further tests

Skunk Works now had to design, construct and flight test two manned demonstrators as part of Phase 2, or Have Blue. To build the demonstrators, Ben Rich had to raise $10.4 million from the Lockheed management, which was secured by June. Phase 2 encompassed three main objectives, which were the validation of: reduced visibility in the radio wave

Radio Wave

Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...

, infrared

Infrared

Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

, and visual spectrums and reduced acoustical observability; acceptable flying qualities; and the "modeling capabilities that accurately predict low observable characteristics of an aircraft in flight".

Construction of both Have Blue demonstrators used leftover tools from the C-5 program. Final assembly of HB1001 was originally scheduled to end in August, before being ground tested until mid-October. The secret roll-out was envisaged to occur on 23 October, after which the aircraft would be dismantled and flown to the test area. On 1 September, however, with HB1001 partially complete, Lockheed machinists went on a four-month strike. A group of managers instead took over the job of assembly, which was completed in six weeks, with ground tests beginning on 17 October.

While superficially similar to the later F-117, the Have Blue prototypes were smaller aircraft, about one quarter the weight of the F-117, with a wing sweep

Swept wing

A swept wing is a wing planform favored for high subsonic jet speeds first investigated by Germany during the Second World War. Since the introduction of the MiG-15 and North American F-86 which demonstrated a decisive superiority over the slower first generation of straight-wing jet fighters...

 of 72.5° and inward-canted vertical tails. Radar-absorbent material (RAM), developed in a Lockheed laboratory, were applied to the aircraft's flat surfaces – for the windscreen, special coatings were applied to give them metallic characteristics. The aircraft's gross weight of 9,200–12,500 lb (4,173–5,669 kg) enabled the aircraft to use the landing gear from the Northrop F-5 fighter. The aircraft's powerplant

Aircraft engine

An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...

s were two 2950 pound-forces (13.1 kN) General Electric J85-GE-4As

General Electric J85

-External links:**...

 of the T-2B Buckeye. Because stealth took precedence above all else, the aircraft was inherently unstable. As a result, a quadruple redundant fly-by-wire

Fly-by-wire

Fly-by-wire is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires , and flight control computers determine how to move the actuators at each control...

 (FBW) flight control system was integrated into the aircraft to give it normal flying characteristics. The flight control system was borrowed from the F-16. The overwing engine inlet was covered by a low-RCS grid; during takeoffs, when more air is need, blow-in doors were constructed at the upper fuselage to admit additional airflow.

Throughout the one and a half months after the start of ground tests, HB1001, the first of two demonstrators, underwent tests in preparations for the first flight. Flight instrumentation was checked first, followed by a thorough shakedown

Shakedown (testing)

A shakedown is a period of testing or a trial journey undergone by a ship, aircraft or other craft and its crew before being declared operational. Statistically, a proportion of the components will fail after a relatively short period of use, and those that survive this period can be expected to...

 of the aircraft. In early November, two semi-trailer

Semi-trailer

A semi-trailer is a trailer without a front axle. A large proportion of its weight is supported by a road tractor, a detachable front axle assembly known as a dolly, or the tail of another trailer...

s were parked parallel to each other outside Building 82; a camouflage net was thrown over the top to cover the demonstrator during outdoor engine runs. During the engine tests, a local resident complained about the noise, but Have Blue retained its secrecy. HB1001 received a layer of iron-coat paint; during the weekend of 12–13 November, the aircraft received a camouflage scheme devised by Alan Brown, Have Blues chief technical engineer. The scheme, consisting of three colors, each with three tones, was used to deceive any casual onlooker from recognizing the design's characteristic faceting. The aircraft was disassembled and loaded onto a C-5 – on 16 November, the aircraft was flown from Burbank Airport

Bob Hope Airport

Bob Hope Airport is a public airport located 3 miles northwest of the central business district of Burbank, a city in Los Angeles County, California, United States...

 (since renamed Bob Hope Airport) to Area 51

Area 51

Area 51 is a military base, and a remote detachment of Edwards Air Force Base. It is located in the southern portion of Nevada in the western United States, 83 miles north-northwest of downtown Las Vegas. Situated at its center, on the southern shore of Groom Lake, is a large military airfield...

 at Groom Lake

Groom Lake

Groom Lake is a salt flat in Nevada used for runways of the Nellis Bombing Range Test Site airport on the north of the Area 51 USAF military installation. The lake at elevation is ~ from north to south and from east to west at its widest point...

, Nevada

Nevada

Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...

. Upon touchdown, the aircraft was reassembled before undergoing another round of testing prior to the first flight. After four taxi tests, HB1001 was ready for test flights.

HB1001

HB1001 made its first flight on 1 December 1977 at the hands of Lockheed test pilot, Bill Park. He would fly the next four sorties, all chased by a T-38 piloted by Major (later Lieutenant Colonel) Ken Dyson. Dyson, an F-15 Eagle pilot, was previously approached by United States Air Force

United States Air Force

The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

 personnel about the project in 1976. He made his first flight on HB1001 on 17 January 1978, chased by Park. In fact, the two would be the only test pilots of Have Blue, alternating between the demonstrator and the chase plane. Flight test results allowed engineers to refine the FBW system. At the same time, they verified predictions made earlier by aerodynamic engineers on the aircraft's behaviour.

Flight tests proceeded fairly smoothly until 4 May 1978, when HB1001 was making its 36th flight. The hard landing resulted in the gear being jammed in a semi-retracted position. Efforts to lower the gear were unsuccessful, and the pilot, Bill Park, ejected at 10000 feet (3,048 m) when fuel ran out. The aircraft was destroyed on impact in the vicinity of the Groom Lake

Groom Lake

Groom Lake is a salt flat in Nevada used for runways of the Nellis Bombing Range Test Site airport on the north of the Area 51 USAF military installation. The lake at elevation is ~ from north to south and from east to west at its widest point...

 facility. Park survived, but suffered a concussion, forcing him from further test flights. Dyson, who was in the chase plane, recounted: "Just before touchdown the airplane pitched up... It seemed it slammed down on the ground real hard... He [Park] raised the gear on the go around, and when he tried to extend it on approach, only one of the mains and the nose wheel came down. All this time, gas was being consumed... I suggested he climb up to 10,000 feet for ejection... He started climbing, but the engine started flaming out

Flameout

A flameout refers to the failure of a jet engine caused by the extinction of the flame in the combustion chamber. It can be caused by a number of factors, including fuel exhaustion; compressor stall; insufficient oxygen supply; foreign object damage ; severe inclement weather; and mechanical...

, from the lack of fuel, so he ejected."

HB1002

At the time of the crash, HB1002 was almost complete, with the lessons learned from the HB1001 incorporated into the aircraft, including the rebuilding of the aft fuselage. HB1002 was distinguished from the prototype in having a gray paint coat. It did not have the flight test instrumentation boom present on HB1001's nose. As the aircraft was used to test RCS returns, the unstealthy spin recovery chute was removed, and the aircraft was covered in RAM. It first flew on 20 July 1978 at the controls of Dyson, who would be the only pilot to fly the aircraft.

HB1002 was lost on 11 July 1979 during the aircraft's 52nd flight. A hydraulic

Hydraulic fluid

Hydraulic fluids, also called hydraulic liquids, are the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water...

 leak caused an engine fire, resulting in the loss of hydraulic pressure, which in turn caused the severe pitch oscillation

Oscillation

Oscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes...

s. The pilot ejected safely, while the aircraft was written-off. It was later discovered that an engine exhaust clamp had loosened, allowing the hot exhaust to migrate to the right engine compartment. The heat built up there, failing the hydraulic lines. The debris from both aircraft were secretly buried somewhere within the Nellis complex. Despite the crashes, Have Blue was considered a success.

Senior Trend

In October 1977, just prior to Phase 2 of the XST competition, Lockheed was tasked with exploring possible operational aircraft. Just a month later, on the day HB1001 was transported to Groom Lake, the Air Force awarded the company a contract under the code name Senior Trend. The Air Force wanted to exploit the revolutionary technologies developed during the Have Blue program. The Tactical Air Command

Tactical Air Command

Tactical Air Command is an inactive United States Air Force organization. It was a Major Command of the United States Air Force, established on 21 March 1946 being headquartered at Langley Air Force Base, Virginia...

 ordered five full-scale development and twenty production aircraft.

Based on the Have Blue demonstrators, Senior Trend aircraft were different from their predecessors in several aspects. The wings exhibited less sweep to resolve a center-of-gravity

Center of gravity

In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...

 problem discovered during tests. The front fuselage was shortened to give the pilot a better view. And, the vertical stabilizers were canted outwards from the centerline. Additionally, provisions were made to include two weapons bays, each of which would accommodate a single 2000 pounds (907.2 kg) laser-guided bomb

Laser-guided bomb

A laser-guided bomb is a guided bomb that uses semi-active laser homing to strike a designated target with greater accuracy than an unguided bomb. LGBs are one of the most common and widespread guided bombs, used by a large number of the world's air forces.- Overview :Laser-guided munitions use a...

, or the B61

B61 nuclear bomb

The B61 nuclear bomb is the primary thermonuclear weapon in the U.S. Enduring Stockpile following the end of the Cold War. It is an intermediate yield strategic and tactical nuclear weapon featuring a two-stage radiation implosion design....

 tactical nuclear bomb

Tactical nuclear weapon

A tactical nuclear weapon refers to a nuclear weapon which is designed to be used on a battlefield in military situations. This is as opposed to strategic nuclear weapons which are designed to menace large populations, to damage the enemy's ability to wage war, or for general deterrence...

.

Beset by early construction problems, the first FSD aircraft was transferred to Groom Lake in May 1981 inside a C-5. Further problems, this time with fuel leaks, delayed the first flight. Under the control of Harold Farley, the aircraft took off on 18 June for its maiden flight, nine months after the July 1980 first flight originally envisaged. The first production F-117A was delivered in 1982, and operational capability was achieved in October 1983; the 59th and last F-117 was delivered in 1990.

Specifications

See also

External links

• Have Blue page at FAS.org