Editing Lockheed F-117 Nighthawk (section)

== Development ==

=== Background and ''Have Blue'' ===
{{main|Lockheed Have Blue}}

In 1936, [[Robert Watson Watt]], the British [[radar]] pioneer, noted that measures to reduce an object's [[radar cross-section]] (RCS) could be used to evade radar detection.<ref name= "bomber 277">Gunston and Gilchrist 1993, p. 277.</ref> In 1962, [[Pyotr Ufimtsev]], a [[:Soviet Union|Soviet]] mathematician, published a seminal paper titled ''Method of Edge Waves in the Physical Theory of Diffraction'' in the journal of the Moscow Institute for Radio Engineering, in which he showed that the strength of the radar return from an object is related to its edge configuration, not its size.<ref name="dtic" /> Ufimtsev was extending theoretical work published by the German physicist [[Arnold Sommerfeld]].<ref name="Centennial" /><ref name="dtic" />{{rp|xiii}}<ref name="filling" /> Ufimtsev demonstrated that he could calculate the RCS across a wing's surface and along its edge. The obvious and logical conclusion was that even a large aircraft could reduce its radar signature by exploiting this principle. However, the resulting design would make the aircraft [[Relaxed stability|aerodynamically unstable]], and the state of computer technology in the early 1960s could not provide the kinds of flight computers which would later allow aircraft such as the F-117 and [[Northrop Grumman B-2 Spirit|B-2 Spirit]] to stay airborne. By the 1970s, when Lockheed analyst Denys Overholser found Ufimtsev's paper, computers and software had advanced significantly, and the stage was set for the development of a stealth airplane.<ref name="Advent" /><ref name="crickmore 14"/>

[[File:F-117 Grey Dragon.jpg|thumb|F-117A painted in "Gray Dragon" experimental camouflage scheme|alt=Aircraft parked inside an open hangar]]
The F-117 was conceived after the [[Vietnam War]], where increasingly sophisticated Soviet [[surface-to-air missile|SAMs]] had downed heavy bombers.<ref name="crickmore 9">Crickmore and Crickmore 2003, p. 9.</ref> The heavy losses inflicted by Soviet-made SAMs upon the [[Israeli Air Force]] in the [[Yom Kippur War|1973 Yom Kippur war]] also contributed to a 1974 [[Defense Science Board]] assessment that in case of a conflict in Central Europe, air defenses would likely prevent [[NATO]] air strikes on targets in Eastern Europe.<ref name=":0">{{Cite web |last=Sweetman |first=Bill |date=January 2008 |title=Unconventional Weapon |url=https://www.airspacemag.com/military-aviation/unconventional-weapon-23371597/ |access-date=22 November 2020 |website=[[Air & Space Magazine]] |language=en}}</ref>

It was a [[black project]], remaining an ultrasecret program for much of its life.<ref name="maxwell" /><ref name="bbc" /><ref name="crickmore 14">Crickmore and Crickmore 2003, p. 14.</ref> The project began in 1975 with a model called the "Hopeless Diamond"<ref name="rich" /><ref name="f117reunion" /><ref name="crickmore 12">Crickmore and Crickmore 2003, p. 12.</ref> (a wordplay on the [[Hope Diamond]] because of its appearance). The following year, the [[Defense Advanced Research Projects Agency]] (DARPA) issued Lockheed Skunk Works a contract to build and test two Stealth Strike Fighters, under the code name "''[[Lockheed Have Blue|Have Blue]]''".<ref name="Goodall p.19" /><ref name="crickmore 1314">Crickmore and Crickmore 2003, pp. 13-14.</ref> These subscale aircraft incorporated jet engines of the [[Northrop T-38 Talon|Northrop T-38A]], [[fly-by-wire]] systems of the [[General Dynamics F-16 Fighting Falcon|F-16]], landing gear of the [[Fairchild Republic A-10 Thunderbolt II|A-10]], and [[Environmental control system|environmental systems]] of the [[Lockheed C-130 Hercules|C-130]].<ref name="Goodall p.19" /> By bringing together existing technology and components, Lockheed built two demonstrators under budget, at $35&nbsp;million for both aircraft, and in record time.<ref name="Goodall p.19" /> [[Undersecretary of Defense for Research and Engineering]] [[William J. Perry]] was instrumental in shepherding the project.<ref name="csisrw">{{cite news |last1= Wagner |first1= Rich |last2= Tegnelia |first2= Jim |title= Technology-Strategy Seminar: NATO's AirLand Battle Strategy and Future Extended Deterrence |url= https://www.youtube.com/watch?v=rSukv1CcORk |publisher= Center for Strategic & International Studies Center for Strategic & International Studies}}</ref>

The [[maiden flight]] of the demonstrators occurred on 1&nbsp;December 1977.<ref name="eden" /><ref name="crickmore 1820">Crickmore and Crickmore 2003, pp. 18-20.</ref> Although both aircraft crashed during the demonstration program, test data gathered proved positive.<ref name="crickmore 2023">Crickmore and Crickmore 2003, pp. 20-23.</ref><ref name= "bomber 2789">Gunston and Gilchrist 1993, pp. 278-279.</ref>  The success of ''Have Blue'' led the government to increase funding for [[stealth technology]]. Much of that increase was allocated towards the production of an operational stealth aircraft, the Lockheed F-117, under the program code name ''Senior Trend''.<ref name="goodall" /><ref name="f-117a" />

=== ''Senior Trend'' ===
The decision to produce the F-117 was made on 1 November 1978, and a contract was awarded to Lockheed Advanced Development Projects, popularly known as the Skunk Works, in [[Burbank, California]].<ref name="rich1" /><ref name="crickmore 25">Crickmore and Crickmore 2003, p. 25.</ref> The program was led by [[Ben Rich (engineer)|Ben Rich]], with Alan Brown as manager of the project.<ref name="crickmore 1011">Crickmore and Crickmore 2003, pp. 10-11.</ref><ref>{{cite web |url=https://www.youtube.com/watch?v=mzQPIlXe2H0 |archive-url=https://web.archive.org/web/20140313124234/http://www.youtube.com/watch?v=mzQPIlXe2H0 |archive-date=13 March 2014 |url-status=dead |title=YouTube |via=YouTube}}</ref> Rich called on Bill Schroeder, a Lockheed mathematician, and Overholser, a mathematician and radar specialist, to exploit Ufimtsev's work. The three designed a computer program called "Echo", which made possible the design an airplane with flat panels, called facets, which were arranged so as to scatter over 99% of a radar's signal energy "painting" the aircraft.<ref name="Advent" /><ref name="discovery" /><ref name="crickmore 1011"/>

The first YF-117A, serial number ''79-10780'', made its maiden flight from Groom Lake ([[Area 51]]), Nevada, on 18 June 1981,<ref name="Goodall p.27" /><ref name= "bomber 279">Gunston and Gilchrist 1993, p. 279.</ref> only 31 months after the full-scale development decision. The first production F-117A was delivered in 1982, and operational capability was achieved in October 1983.<ref name="Centennial" /><ref name="Goodall p.29" /> The [[4450th Tactical Group]] stationed at [[Nellis Air Force Base]], Nevada, was tasked with the operational development of the early F-117, and between 1981 (prior to the arrival of the first models) and 1989, the group used [[LTV A-7 Corsair II]]s for training, to bring all pilots to a common flight-training baseline and later as chase planes for F-117A tests.<ref name=Holder&Wallace>Holder and Wallace 2000, {{page needed|date=September 2023}}.</ref>

[[File:Lockheed F-117A Nighthawk 79-7084.jpg|thumb|F-117 79-7084 is being refueled by a [[Boeing KC-135 Stratotanker]] of the 4450th Tactical Group in 1983.]]
The F-117 was secret for much of the 1980s. Many news articles discussed what they called an "[[F-19]]" stealth fighter, and the [[Testor Corporation]] produced a very inaccurate [[scale model]]. When an F-117 crashed in [[Sequoia National Forest]] in July 1986, killing the pilot and starting a fire, the USAF established [[restricted airspace]].<ref>{{cite web | url=https://www.youtube.com/watch?v=ruBeOIcKIdo&ab_channel=ForrestHaggertyChannel | title=F-117 Nighthawk Crash 1986. On Site Visit | website=[[YouTube]] | date=10 November 2024 }}</ref> Armed guards prohibited entry, including firefighters, and a [[helicopter gunship]] circled the site. All F-117 debris was replaced with remains of a [[F-101A Voodoo]] crash stored at Area 51. When another fatal crash in October 1987 occurred inside Nellis, the military again provided little information to the press.{{r|afmag-richelson}}

The USAF denied the existence of the aircraft until 10 November 1988, when Assistant Secretary of Defense [[J. Daniel Howard]] displayed a grainy photograph at a Pentagon press conference, disproving the many inaccurate rumors about the shape of the "F-19".<ref>{{Cite news |last1=Jr |first1=John H. Cushman |last2=Times |first2=Special To the New York |date=11 November 1988 |title=Air Force Lifts Curtain, a Bit, on Secret Plane |language=en-US |work=The New York Times |url=https://www.nytimes.com/1988/11/11/us/air-force-lifts-curtain-a-bit-on-secret-plane.html |access-date=16 September 2023 |issn=0362-4331}}</ref> After the announcement, pilots could fly the F-117 during daytime and no longer needed to be associated with the A-7, flying the T-38 [[supersonic]] trainer for travel and training, instead.{{r|crickmorep2003}} In April 1990, two F-117s flew to Nellis, arriving during daylight and publicly displayed to a crowd of tens of thousands.<ref name="dreamlandresort">Gregos, J. [http://www.dreamlandresort.com/black_projects/f117_intro.html "First Public Display of the F-117 at Nellis AFB April 21, 1990"]. dreamlandresort.com. Retrieved 27 April 2012.</ref><ref>{{Cite news |last=Morrissey |first=David H. |date=22 April 1990 |title=Secret Fighter Steals Into Public View |pages=[https://www.newspapers.com/article/albuquerque-journal-secret-fighter-steal/130919764/ A1], [https://www.newspapers.com/article/albuquerque-journal-analysts-say-radar-c/130919893/ A10] |work=[[Albuquerque Journal]] |via=[[Newspapers.com]]}}</ref>

[[File:Lockheed F-117.ogg|thumb|thumbtime=32|right|F-117 flight demonstration]]
Five full-scale development<!-- (FSD) --> aircraft were built, designated "YF-117A".<ref name="designation-systems" /> The last of 59 production F-117s were delivered on 3 July 1990.<ref name="Goodall p.29" /><ref name="donald" /> As the USAF has stated, "Streamlined management by Aeronautical Systems Center, [[Wright-Patterson AFB]], [[Ohio]], combined breakthrough stealth technology with concurrent development and production to rapidly field the aircraft... The F-117A program demonstrates that a stealth aircraft can be designed for reliability and maintainability."<ref name="Nat_Museum_factsht" />

=== Designation ===
The operational aircraft was officially designated "F-117A".<ref name="dtic3" /><ref name= "bomber 277"/> Most modern U.S. military aircraft use [[1962 United States Tri-Service aircraft designation system|post-1962 designations]] in which the designation "F" is usually an [[Fighter aircraft|air-to-air fighter]], "B" is usually a [[bomber]], "A" is usually a ground-attack aircraft, etc. (Examples include the [[McDonnell Douglas F-15 Eagle|F-15]], the B-2, and the [[Grumman A-6 Intruder|A-6]].) The F-117 is primarily an attack aircraft,<ref name=eden_p240>{{harvnb|Eden|2004|p=240.}}</ref> so its "F" designation is inconsistent with the [[United States Department of Defense|Department of Defense]] system. This is an inconsistency that has been repeatedly employed by the USAF with several of its attack aircraft since the late 1950s, including the [[Republic F-105 Thunderchief]] and [[General Dynamics F-111 Aardvark]]. A televised documentary quoted project manager Alan Brown as saying that [[Robert J. Dixon]], a four-star USAF general who was the head of [[Tactical Air Command]], felt that the top-notch USAF fighter pilots required to fly the new aircraft were more easily attracted to an aircraft with an "F" designation for fighter, as opposed to a bomber ("B") or attack ("A") designation.<ref name="history" /><ref>{{cite web |url=https://www.youtube.com/watch?v=81S4W8rOCgo&t=1658s |url-status=dead |title=Modern Marvels S11E62 F117 |last=Moderns |date=13 April 2017 |via=YouTube |access-date=22 July 2018 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308223809/https://www.youtube.com/watch?v=81S4W8rOCgo&t=1658s}}</ref> Early on, one potential air-to-air mission considered for the F-117 was to hunt down the Soviet [[Beriev A-50|A-50 "Mainstay"]] airborne warning and control system<!-- (AWACS) -->. However, this was not deemed to be effective and this mission was passed to the nascent [[Advanced Tactical Fighter]], which eventually became the [[Lockheed Martin F-22 Raptor|F-22 Raptor]].<ref name="WMOF_JB">{{cite AV media |url=https://www.youtube.com/watch?v=lltMfkj1yPU |title=F-117 Nighthawk and F-22 Raptor with Jim "JB" Brown, President & CEO National Test Pilot School |date=21 November 2022 |publisher=Western Museum of Flight |location=Torrance, California |access-date=30 June 2023 |people=[[James E. Brown III|Brown, James "JB"]]}}</ref>

The designation "F-117" seems to indicate that it was given an official designation prior to the 1962 U.S. Tri-Service Aircraft Designation System and could be considered numerically to be a part of the earlier [[Century Series]] of fighters. The assumption prior to the revealing of the aircraft to the public was that it would likely receive the F-19 designation, as that number had not been used, but no other aircraft were to receive a "100" series number following the F-111. Soviet fighters obtained by the U.S. via various means under the [[Constant Peg]] program<ref name="airforce-magazine" /> were given F-series numbers for their evaluation by U.S. pilots, and with the advent of the [[Teen Series]] fighters, most often Century Series designations.<ref name="Merlin_groom_2011_p32">Merlin 2011, p. 32.</ref>

As with other exotic military aircraft types flying in the southern Nevada area, such as captured fighters, an arbitrary radio call of "117" was assigned. This same radio call had been used by the enigmatic [[4477th Test and Evaluation Squadron]], also known as the "Red Hats" or "Red Eagles", that often had flown expatriated [[Mikoyan#List of MiG aircraft|MiG jet fighters]] in the area, but no relationship existed between the call and the formal F-19 designation then being considered by the USAF. Apparently, use of the "117" radio call became commonplace and when Lockheed released its first flight manual (i.e., the USAF "dash one" manual for the aircraft), F-117A was the designation printed on the cover.<ref name="Miller1990" />