Editing Lockheed F-117 Nighthawk (section)

=== 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" />