Lockheed F-117A Nighthawk

The Lockheed F-117 Nighthawk is a stealth ground attack aircraft formerly operated by the United States Air Force. The F-117A's first flight was in 1981, and it achieved Initial Operational Capability status in October 1983.[1] The F-117A was "acknowledged" and revealed to the world in November 1988.[4]

As a product of the Skunk Works and a development of the Have Blue prototype, it became the first operational aircraft initially designed around stealth technology. The F-117A was widely publicized during the Gulf War of 1991.

The Air Force retired the F-117 on 22 April 2008,[2] primarily due to the purchasing and eventual deployment of the more effective F-22 Raptor[5][6] and F-35 Lightning II.

Development

The F-117 was born after combat experience in the Vietnam War after increasing sophistication of Soviet surface-to-air missiles (SAMs) downed heavy bomber flights.[7]

In 1964, Pyotr Ya. Ufimtsev, a Russian mathematician, published a seminal paper, "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 a radar return is proportional to the edge configuration of an object, not its size.[8] Ufimtsev was extending theoretical work published by the German physicist Arnold Sommerfeld.[9][10][11] Ufimtsev demonstrated that he could calculate the radar cross-section across a wing's surface and along its edge. The obvious conclusion was that even a large airplane could be made stealthy by exploiting this principle. However, the airplane's design would make it aerodynamically unstable, and the state of computer science in the early 1960s could not provide the kinds of flight computers which allow aircraft such as the F-117, F-22 Raptor and B-2 Spirit to stay airborne. However, by the 1970s, when a Lockheed analyst reviewing foreign literature found Ufimtsev's paper, computers and software had advanced significantly, and the stage was set for the development of a stealthy airplane.[12]

The F-117 was a black project, an ultra-secret program for much of its life, until the late 1980s.[13] The decision to produce the F-117A was made in 1978, and a contract awarded to Lockheed Advanced Development Projects, popularly known as the "Skunk Works", in Burbank, California.[citation needed] The program was led by Ben Rich. Rich called on Bill Schroeder, a Lockheed mathematician, and Denys Overholser, a computer scientist, to exploit Ufimtsev's work. They designed a computer program called Echo, which made it possible to 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 airplane.[14][15][12]
F-117A painted in 'Gray Dragon' experimental camouflage scheme
F-117A painted in 'Gray Dragon' experimental camouflage scheme
F-117 taxiing.
F-117 taxiing.

The project began with a model called "The Hopeless Diamond" in 1975 due to its bizarre appearance. In 1977 Lockheed produced two 60% scale models under the Have Blue contract. The Have Blue program lasted from 1976 to 1979. The F-117 first flew in June 1981, only 31 months after the full-scale development decision. The first production F-117A was delivered in 1982, operational capability was achieved in October 1983, and the last of 59 airplanes was delivered in the summer of 1990.[9] The Air Force denied the existence of the aircraft until 1988, when a grainy photograph was released to the public. In April 1990 two were flown into Nellis Air Force Base, Nevada, arriving during daylight and visible to a crowd of tens of thousands.

As the Air Force 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."[1] The aircraft maintenance statistics are comparable to other tactical fighters of similar complexity. Logistically supported by Sacramento Air Logistics Center, McClellan AFB, California, the F-117A is kept at the forefront of technology through a planned weapon system improvement program located at USAF Plant 42 at Palmdale, California.

Several of the F-117s were painted in a grey camouflage pattern in an experiment to determine the effectiveness of the F-117's stealth during daylight conditions. 2004 and 2005 saw several mid-life improvement programs implemented on the F-117, including an avionics upgrade.
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[edit] Designation
An F-117A parked at Langley AFB, Virginia.
An F-117A parked at Langley AFB, Virginia.

The 59 operational aircraft have an official designation of "F-117A".[16] The five Full Scale Development (FSD) aircraft are designated "YF-117A".[17]

Most modern U.S. military aircraft use post-1962 designations in which the designation "F" is usually an air-to-air fighter, "B" is usually a bomber, "A" is usually a ground-attack aircraft, etc. (Examples include the F-15, the B-2, and the A-6.) The Stealth Fighter is primarily a ground-attack plane so its "F" designation is inaccurate.

The designation "F-117" would seem 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 designation F-19 as that number had not been used. However there were no other aircraft to receive a "100" series number following the F-111. The explanation is an example of general secrecy on the part of the U.S. Government. Captured Soviet fighters were given F-series numbers for their evaluation by U.S. test pilots, and with the advent of the "Teen Series" fighters, most often 'Century Series' designations.

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 "Red Hats/Red Eagles" unit that often had flown expatriated MiGs in the area, but there was no relationship to the call and the formal F-19 designation then being considered by the Air Force. Apparently, use of the "117" radio call became commonplace and when Lockheed released its first flight manual ("dash one"), F-117A was the designation imprinted on the cover.[18]

A recent televised documentary quoted a senior member of the F-117A development team as saying that the top-notch fighter pilots required to fly the new aircraft were more easily attracted to an "F" plane, as opposed to a "B" or "A" aircraft.[19]

[edit] Nicknames

The aircraft's official name is "Night Hawk",[20] however the alternate form "Nighthawk" is frequently used.

Before it was given an official name, the engineers and test pilots referred to the ungainly aircraft, which went into hiding during daylight to avoid detection by Soviet satellites, as "Cockroach", a name that is still sometimes used.[citation needed] As it prioritized stealth over aerodynamics, the first model was nicknamed "The Hopeless Diamond".[21] Similarly, it earned the nickname "Wobbly-Goblin" due to its alleged instability at low speeds; according to F-117 pilots, the nickname is undeserved.[22] "Wobbly (or wobblin' Goblin" is very likely a holdover from the early Have Blue / Senior Trend (FSD) days of the project when instability was a problem. In the USAF, "Goblin" (without wobbly) persists as a nickname because of the aircraft's appearance. Locals in the area around Holloman Air Force Base refer to the aircraft simply as the "Stealth".

F-117 pilots call themselves "Bandits". Each of the 558 Air Force pilots who have flown the F-117 have a Bandit number, such as "Bandit 123", that indicates the sequential order of their first flight in the F-117.[23]

[edit] Design

About the size of an F-15C Eagle, the single-seat F-117A is powered by two non-afterburning General Electric F404 turbofan engines, and has quadruple-redundant fly-by-wire flight controls. It is air refuelable. In order to lower development costs, the avionics, fly-by-wire systems, and other parts are derived from the F-16 Fighting Falcon, F/A-18 Hornet and F-15E Strike Eagle. The parts were originally described as spares on budgets for these aircraft, to keep the F-117 project secret.[citation needed]

Among the penalties for stealth are lower engine power thrust, due to losses in the inlet and outlet, a very low wing aspect ratio, and a high sweep angle (50° needed to deflect incoming radar waves to the sides.[24]

The F-117A is equipped with sophisticated navigation and attack systems integrated into a digital avionics suite. It carries no radar, which lowers emissions and cross-section. It navigates primarily by GPS and high-accuracy inertial navigation. Missions are coordinated by an automated planning system that can automatically perform all aspects of a strike mission, including weapons release. Targets are acquired by a thermal imaging infrared system, slaved to a laser that finds the range and designates targets for laser-guided bombs.

The F-117A's split internal bay can carry 5,000 lb (2,300 kg) of ordnance. Typical weapons are a pair of GBU-10, GBU-12, or GBU-27 laser-guided bombs, two BLU-109 penetration bombs, or two Joint Direct Attack Munitions (JDAMs), a GPS/INS guided stand-off bomb.

[edit] Operational history
An F-117A during landing employing a drag-chute.
An F-117A during landing employing a drag-chute.

During the program's early years, from 1984 to mid-1992, the F-117A fleet was based at Tonopah Test Range, Nevada where it served under the 4450th Tactical Group. However, because the F-117 was classified during this time, the 4450th Tactical Group was "officially" located at Nellis Air Force Base, Nevada and equipped with A-7 Corsair II aircraft. The 4450th was absorbed by the 37th Tactical Fighter Wing in 1989. In 1992, the entire fleet was transferred to Holloman Air Force Base, New Mexico, where it was placed under the command of the 49th Fighter Wing. The move eliminated the need for Key Air flights, which flew 22,000 passenger trips on 300 flights from Nellis to Tonopah per month.

The F-117 has been used several times in war. Its first mission was during the United States invasion of Panama in 1989.[25] During that invasion two F-117A Nighthawks dropped two bombs on Rio Hato airfield.
F-117s in formation
F-117s in formation

During the Gulf War in 1991, the F-117A flew approximately 1,300 sorties and scored direct hits on 1,600 high-value targets in Iraq[1] while flying 6,905 combat flying hours.[26] The F-117 comprised only 2.5 percent of the American aircraft in Iraq yet struck more than 40 percent of the strategic targets.[27] "During their mission, the F-117A pilots delivered over 2,000 tons of precision-guided ordnance with a hit rate of better than 80 percent. Although the 37th Tactical Fighter Wing Provisional and its 42 stealth fighters represented just 2.5 percent of all allied fighter and attack aircraft in the Gulf, the F-117As were assigned against more than 31 percent of the strategic Iraqi military targets attacked during the first 24 hours of the air campaign."[26] However, during the war, it performed rather poorly in its dropping of smart bombs on Iraqi military targets, achieving a success rate of only 40%.[28]

It was among the only U.S. or coalition aircraft to strike targets in downtown Baghdad. Among the aircraft the Nighthawk shared this distinction with were the F-16s which attacked Baghdad during daylight on 19 January 1991 during the "Package Q" mission - the largest single strike flown during the war.[29]

Since moving to Holloman AFB in 1992, the F-117A and the men and women of the 49th Fighter Wing have deployed to Southwest Asia more than once. On their first trip, the F-117s flew non-stop from Holloman to Kuwait, a flight of approximately 18.5 hours – a record for single-seat fighters that stands today.[1]

It has since been used in Operation Allied Force in 1999, Operation Enduring Freedom in 2001 and in Operation Iraqi Freedom in 2003.

[edit] Combat losses
Canopy of F-117 shot down on 27 March 1999, near the village of Buđanovci, Serbia (Museum of Aviation in Belgrade)
Canopy of F-117 shot down on 27 March 1999, near the village of Buđanovci, Serbia (Museum of Aviation in Belgrade)

One F-117 has been lost in combat, to the Yugoslav Army. On 27 March 1999, during the Kosovo War, the 3rd Battalion of the 250th Missile Brigade under the command of Colonel Zoltán Dani, equipped with the Isayev S-125 'Neva' (NATO designation SA-3 'Goa' anti-aircraft missile system, downed a F-117A callsign "Vega 31," serial number 82-806 with a Serbian improved Neva-M missile.[30][31] According to NATO Commander Wesley Clark and other NATO generals, Yugoslav air defenses found that they could detect F-117s with their radars operating on unusually long wavelengths. This made them visible on radar screens for short times.

Reportedly several SA-3s were launched from approximately 8 miles out, one of which detonated in close proximity to the F-117A, forcing the pilot to eject. Though still classified, it has long been believed that the F-117 possesses no radar warning indicator, so the pilot's first indication of an incoming missile was likely seeing its flame. At this distance and combined speed the pilot had about 6 seconds to react before impact. According to an interview, Zoltán Dani was able to keep most of his missile sites intact by keeping them on the move, and had a number of spotters spread out looking for F-117s and other NATO aircraft, he also personally supervised the modification of his targeting radar to increase its wavelength. The commanders and crews of the SAMs guessed the flight paths of earlier F-117A strikes from rare radar spottings and positioned their SAM launchers and spotters accordingly. It is believed that the SA-3 crews and spotters were able to locate and track F-117A 82-806 visually, probably with the help of infra-red and night vision systems. He also claimed that his battery shot down an F-16 as well.

The F-117 pilot survived and was later rescued by U.S. Air Force Pararescue personnel. However, the wreckage of the F-117 was not promptly bombed, due to possible media fallout from news footage of civilians around the wreckage. The Serbs are believed to have invited Russian personnel to inspect the remains, inevitably compromising the then 25-year old U.S. stealth technology.[32] Since the United States did not destroy the wreckage, the remains can still be seen today at the Museum of Aviation in Belgrade close to Belgrade Nikola Tesla Airport. An error of assumption was made by many as to the identity of the pilot. While the name "Capt Ken 'Wiz' Dwelle" was painted on the canopy, it was made public in 2007 that the actual pilot was Lt Col. Dale Zelko, USAF.[33][34][35][36]

Some American sources acknowledge that a second F-117A was also damaged during a raid in the same campaign, and although it made it back to its base, it supposedly never flew again.[37][38]

[edit] Retirement

Despite its successes in the Kosovo and Iraq Wars and its high mission-capable rate, the F-117 was nonetheless designed with late 1970s technologies. Its stealth technology, while still more advanced than that of any other aircraft except the B-2 Spirit, F-22 and F-35, is maintenance heavy. Furthermore, the facet-based stealth design has been surpassed by newer technology. Program Budget Decision 720 (PBD 720), dated 28 December 2005, proposed retiring the entire fleet by October 2008 to allow for buying more F-22As. PBD 720 called for 10 aircraft to be retired in FY 2007 and the remaining 42 aircraft in FY 2008 and stated there were other more capable Air Force assets that could provide low observable, precision penetrating weapons capability including the B-2, F-22 and JASSM.[39] The Air Force originally planned to retire the F-117 in 2011. The Air Force later decided to retire the F-117 sooner to shift funds to modernizing the rest of the fleet.[40] This would save an estimated $1.07 billion.[41]
A pair of specially painted F-117 Nighthawks fly off from their last refueling by the Ohio National Guard's 121st Air Refueling Wing
A pair of specially painted F-117 Nighthawks fly off from their last refueling by the Ohio National Guard's 121st Air Refueling Wing

By late 2006, the Air Force had closed the F-117 pilot school,[42] and announced the retirement of the F-117.[43] The first six aircraft to be retired made the last flight on 12 March 2007 after a ceremony at Holloman AFB to commemorate the aircraft's storied career. Brigadier General David Goldfein, commander of the 49th Fighter Wing, said at the ceremony, "With the launch of these great aircraft today, the circle comes to a close - their service to our nation's defense fulfilled, their mission accomplished and a job well done. We send them today to their final resting place - a home they are intimately familiar with - their first, and only, home outside of Holloman."[44]

Unlike most other Air Force aircraft which are retired to Davis-Monthan AFB, the F-117s are being retired to the Tonopah Test Range. At Tonopah, their wings will be removed and the aircraft will be stored in their original hangars.[44] On 11 March 2008 it was reported that the last F-117s in service would touch down on 22 April 2008 in Tonopah Test Range Airfield in Nevada, the site of the F-117's first flight.[45] The F-117 was retired during ceremonies at Palmdale and Tonopah on 22 April 2008.[2] Four aircraft were kept flying beyond April by the 410th Flight Test Squadron at Palmdale for flight test. By the beginning of August, two were remaining, and the last F-117 left Palmdale to fly to Tonopah on 11 August 2008.[46] With the last aircraft leaving for retirement, the 410th was inactivated in a ceremony on 1 August 2008.[47]

[edit] Aircraft on display

The first YF-117A is currently on pedestal display at Nellis Air Force Base, Nevada (N36°13'38.00", W115° 3'33.28") and can be seen from outside the base from Nellis Blvd. The second YF-117A is currently on static display at the National Museum of the Air Force at Wright-Patterson Air Force Base, Ohio. The third YF-117A built is on static display at Holloman Air Force Base, repainted to resemble the first F-117A used to drop weapons in combat. The fourth YF-117A built is currently on static display in the Blackbird Airpark at Air Force Plant 42 in Palmdale, California. Parts of a F-117A are also on display at the Museum of Aviation in Belgrade.[48]

[edit] Specifications
An orthographically projected diagram of the F-117A Nighthawk
An F-117 conducts a live exercise bombing run using GBU-27 laser-guided bombs.
An F-117 conducts a live exercise bombing run using GBU-27 laser-guided bombs.

General characteristics

* Crew: 1
* Length: 69 ft 9 in (20.08 m)
* Wingspan: 43 ft 4 in (13.20 m)
* Height: 12 ft 9.5 in (3.78 m)
* Wing area: 780 ft² (73 m²
* Empty weight: 29,500 lb (13,380 kg)
* Loaded weight: 52,500 lb (23,800 kg)
* Powerplant: 2× General Electric F404-F1D2 turbofans, 10,600 lbf (48.0 kN) each

Performance

* Maximum speed: Mach 0.92 (617 mph, 993 km/h)
* Cruise speed: Mach 0.92
* Range: 930 NM[49] (1720 km)
* Service ceiling 69,000 ft (20,000 m)
* Wing loading: 65 lb/ft² (330 kg/m²
* Thrust/weight: 0.40

Armament

* 2× internal weapons bays with one hardpoint each (total of two weapons) equipped to carry:
o Bombs:
+ BLU-109 hardened penetrator
+ GBU-10 Paveway II laser-guided bomb
+ GBU-12 Paveway II laser-guided bomb
+ GBU-27 Paveway III laser-guided bomb
+ JDAM INS/GPS guided munition

[edit] Popular culture

A Sprint commercial in the 1990s featured a large schematic drawing of the F-117, which was then subsequently identified incorrectly by Candice Bergen, their spokesperson, as a B-2. In the 1980s, the Jane's Information Group misidentified the F-117 as the F-19, and featured fictitious artwork in All the World's Aircraft. Modelmakers Testors and Monogram both released hypothetical "F-19 Stealth" models; neither bore any resemblance to the real F-117. In the 1996 film Executive Decision an airplane called the F-117X is used to transfer an assault team onto another aircraft in midflight. In the film Philadelphia Experiment 2, a transportation experiment sent an F-117 back in time to Nazi Germany.