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96-605: The Lockheed F-117 Nighthawk is a retired American single-seat, subsonic twin-engine stealth attack aircraft developed by Lockheed 's secretive Skunk Works division and operated by the United States Air Force (USAF). It was the first operational aircraft to be designed with stealth technology . Work on what would become the F-117 commenced in the 1970s as a means of countering increasingly sophisticated Soviet surface-to-air missiles (SAMs). During 1976,

192-649: A great circle route. Hence, in case of an engine failure in a twinjet (like Boeing 777 ), the twin-jet could make emergency landings in fields in Canada , Alaska , eastern Russia , Greenland , Iceland , or the British Isles . The Boeing 777 has also been approved by the Federal Aviation Administration for flights between North America and Hawaii , which is the world's longest regular airline route with no diversion airports along

288-403: A radar cross-section (RCS) of about 0.001 m (0.0108 sq ft). Among the penalties for stealth are subsonic speeds to prevent frame heating, heat on the engine inlet and outlet prevent certain thrusting maneuvers, a very low wing aspect ratio , and a high sweep angle (50°) are needed to deflect incoming radar waves to the sides. With these design considerations and no afterburner ,

384-422: A thermal imaging infrared system and a laser rangefinder / laser designator . It is aerodynamically unstable in all three aircraft principal axes and thus requires constant flight corrections via a fly-by-wire (FBW) flight system to maintain controlled flight. Even in the years following its entry to service, the F-117 was a black project , its existence being denied by USAF officials. On 10 November 1988,

480-466: A thermal imaging infrared system, paired with a laser rangefinder / laser designator that finds the range and designates targets for laser-guided bombs . The F-117's split internal bay can carry 5,000 pounds (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, after 2006, two Joint Direct Attack Munitions (JDAM) GPS/INS guided stand-off bombs. The F-117 has

576-531: A British engineer who invented radar , noted that measures to reduce an object's radar cross-section (RCS) could be used to evade radar detection. In 1962, Pyotr Ufimtsev , a 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

672-533: A bomber ("B") or attack ("A") designation. Early on, one potential air-to-air mission considered for the F-117 was to hunt down the Soviet 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 F-22 Raptor . The designation "F-117" seems to indicate that it

768-421: 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 aircraft. The first YF-117A, serial number 79-10780 , made its maiden flight from Groom Lake (" Area 51 "), Nevada, on 18 June 1981, only 31 months after the full-scale development decision. The first production F-117A

864-470: A critical role in the design of American stealth aircraft such as the F-117 and B-2. See also the Forewords written by K. Mitzner to the books: In these two books, P. Ya. Ufimtsev presented the further development and application of PTD and its validation by mathematical theory. In particular, a new version of PTD, based on the concept of elementary edge waves, is presented in his book Fundamentals of

960-600: A high level of secrecy, components were often rerouted from other aircraft programs, ordered using falsified addresses and other details, while $ 3 million worth of equipment was removed from USAF storage without disclosing its purpose. The aircraft is equipped with sophisticated navigation and attack systems integrated into a digital avionics suite. 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 an attack mission, including weapons release. Targets are acquired by

1056-491: A high-frequency asymptotic theory for predicting the scattering of electromagnetic waves from two-dimensional and three-dimensional objects. Among such objects were the finite bodies of revolution (disk, finite cylinder with flat bases, finite cone, finite paraboloid, spherical segment, finite thin wire). This theory is now known as the Physical Theory of Diffraction (PTD). The first results of PTD were collected in

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1152-412: A large amount of maintenance and was eventually superseded by streamlined shapes produced with computer-aided design . Other weapon systems began to take on the F-117's roles, such as the F-22 Raptor gaining the ability to drop guided bombs. By 2005, the aircraft was used only for certain missions, such as if a pilot needed to verify that the correct target had been hit, or when minimal collateral damage

1248-424: A minimum of mass thrust, which eased the task of designing a suitable inlet and nozzle. To obscure the engine from enemy radar, a conductive metal mesh grill was installed in the intake while the exhaust gases were intentionally mixed with cool air to lower the thermal signature. The aircraft is air refuelable and features a V-tail . The maximum speed is 623 mph (1,003 km/h; 541 kn) at high altitude,

1344-456: A new ground-attack radar with air-to-air capability. In that role, the F-117N could carry AIM-120 AMRAAM air-to-air missiles. Twinjet There are three common configurations of twinjet aircraft. The first, common on large aircraft such as airliners, has a podded engine usually mounted beneath, or occasionally above or within, each wing. Most notable examples of such a configuration are

1440-702: A number of research and academic institutions, including the Institute of Radio Engineering and Electronics of the USSR Academy of Sciences (Moscow), Moscow Aviation Institute , the University of California (Los Angeles, Irvine) and most recently, the Moscow State University (Russia, 2007) and the University of Siena (Italy, 2008). Currently he is a retiree and a consultant in the field of electromagnetics. Among his honors and awards are

1536-575: A pair of F-117s landed at Fresno Yosemite International Airport in California. They were scheduled to train with the California Air National Guard F-15 C/D Eagles of the 144th Fighter Wing over the next few days. One aircraft had red letters on its tail, and the other had white letters. One of the two was observed to not be fitted with radar reflectors. That year USAF published photographs on DVIDS ,

1632-406: A photograph of the still-secret F-117, he "promptly giggled and thought [to himself] 'this clearly can't fly ' ". The single-seat F-117 is powered by two non-afterburning General Electric F404 turbofan engines. They were extensively modified to suit a stealth aircraft, such as to have a cooler operational temperature, and somewhat resembled a turbojet instead. The engine was redesigned to produce

1728-456: A short-range widebody, as airlines operating the A300 on short-haul routes had to reduce frequencies to try and fill the high-capacity aircraft, and lost passengers to airlines operating more frequent narrow-body flights. However, after the introduction of ETOPS rules that allowed twin-engine jets to fly long-distance routes that were previously off-limits to them, Airbus was able to further develop

1824-408: A specified distance from an available diversion airport. Overwater flights near diversion airports need not be ETOPS/LROPS-compliant. Since the 1990s, airlines have increasingly turned from four-engine or three-engine airliners to twin-engine airliners to operate transatlantic and transpacific flight routes. On a nonstop flight from America to Asia or Europe, the long-range aircraft usually follows

1920-541: A trijet aircraft) and Boeing worked on new widebody twinjet designs that would become the Airbus A330 and Boeing 777 , respectively. The MD-11's long range advantage was brief as it was soon nullified by the Airbus A330-300 and the extended-range Boeing 767-300ER and Boeing 777-200ER. The Airbus A320 twinjet stands out as the most produced jet airliner. The Boeing 777X is the world's largest twinjet, and

2016-470: Is a Soviet Russian electrical engineer and mathematical physicist , considered the seminal force behind modern stealth aircraft technology . In the 1960s he began developing equations for predicting the reflection of electromagnetic waves from simple two-dimensional and three-dimensional objects. Much of Ufimtsev's work was translated into English , and in the 1970s American Lockheed engineers began to expand upon some of his theories to create

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2112-498: Is also restricted to subsonic speeds as breaking the sound barrier would produce an obvious sonic boom that would increase both its acoustic and infrared footprints. While its performance in air combat maneuvering was less than that of most contemporary fighters, it was strictly an attack aircraft despite being commonly referred to as the "Stealth Fighter". For this reason, it is equipped with integrated sophisticated digital navigation and attack systems, targeting being achieved via

2208-583: Is currently using the aircraft in aggressor squadron and cruise missile training, and research and development. USAF has also slowed the retirement of its current inventory of about 45 F-117s to two to three units a year. This plan should extend the lifetime of the F-117 program to 2034. In March 2019, it was reported that four F-117s had been secretly deployed to the Middle East in 2016 and that one had to make an emergency landing at Ali Al Salem (OKAS), Kuwait sometime late that year. On 13 September 2021,

2304-474: Is not an issue, as one of the engines is more than powerful enough to keep the aircraft aloft (see below). Mostly, ETOPS certification involves maintenance and design requirements ensuring that a failure of one engine cannot make the other one fail also. The engines and related systems need to be independent and (in essence) independently maintained. ETOPS/LROPS is often incorrectly thought to apply only to long overwater flights, but it applies to any flight more than

2400-464: The 410th Flight Test Squadron at Palmdale for flight test. By August, two were remaining. The last F-117 (AF Serial No. 86-0831) left Palmdale to fly to Tonopah on 11 August 2008. With the last aircraft retired, the 410th was inactivated in a ceremony on 1 August 2008. Five aircraft were placed in museums, including the first four YF-117As and some remains of the F-117 shot down over Serbia. Through 2009, one F-117 had been scrapped; AF Serial No. 79-0784

2496-481: 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." Unlike most other USAF aircraft that are retired to Davis-Monthan AFB for scrapping, or dispersal to museums, most of

2592-556: The 757 and updated "classic" variants of the 737 . During that decade only McDonnell Douglas continued development of the trijet design with an update to the DC-10 , the MD-11 , which initially had a range advantage over its closest medium wide-body competitors which were twinjets, the in-production Boeing 767 and Airbus A300/A310. In contrast to McDonnell Douglas sticking with their existing trijet configuration, Airbus (which never produced

2688-518: The 777X in November 2013, while then-CEO Fabrice Brégier preferred to focus on product improvement rather than all-new concepts for 10 years. It would have a 10-abreast economy like the 777; its 565 m (6,081 sq ft) wing, slightly more than the 747-8, would have an 80 m (262 ft) span, as wide as the A380 , for a 892,900 lb (405 t) MTOW compared to 775,000 lb (352 t) for

2784-552: The Amiriyah shelter bombing , killing at least 408 civilians. Much media attention was given to the bombing of telecommunications, water, and transportation infrastructure in Baghdad. Stealth bombers were used due to the perimeter of Baghdad being heavily defended with anti-aircraft weapons. The bombings quickly became part of a propaganda battle with media highlighting the killing of civilians and American claims that stealth bombing

2880-531: The Army of Yugoslavia on 27 March 1999. The aircraft was acquired by a fire control radar at a distance of 8.1 mi (13 km) and an altitude of 26,000 ft (8 km). SA-3s were then launched by a Yugoslav version of the Soviet Isayev S-125 "Neva" (NATO name SA-3 "Goa") anti-aircraft missile system. The launcher was run by the 3rd Battalion of the 250th Air Defence Missile Brigade under

2976-567: The B-2 Spirit , F-22 and JASSM . The planned introduction of the multi-role F-35 Lightning II also contributed to the retirement decision. In late 2006, the USAF closed the F-117 formal training unit (FTU), and announced the retirement of the F-117. The first six aircraft to be retired took their last flight on 12 March 2007 after a ceremony at Holloman AFB to commemorate the aircraft's career. Brigadier General David L. Goldfein , commander of

Lockheed F-117 Nighthawk - Misplaced Pages Continue

3072-546: The Boeing 737 and Airbus A320 . The second has one engine mounted on each side of the rear fuselage, close to its empennage , used by many business jets , although some airliners like the Fokker 70 , Douglas DC-9 and COMAC ARJ21 utilise such a design as well. In the third configuration both engines are within the fuselage, side-by-side, used by most fighters since the 1960s. Later fighters using this configuration include

3168-399: The Boeing 777 , Boeing 787 and Airbus A350 have matched or surpassed older quad-jet designs such as the Boeing 747 and Airbus A340 in these aspects, and twinjets have been more successful in terms of sales than quad-jets. In 2012, Airbus studied a 470-seat twinjet competitor for the Boeing 747-8 with lower operating costs expected between 2023 and 2030, revived after Boeing launched

3264-580: The Defense Advanced Research Projects Agency (DARPA) issued Lockheed with a contract to produce the Have Blue technology demonstrator, the test data from which validated the concept. On 1 November 1978, it was decided to proceed with the F-117 development program. A total of five prototypes would be produced; the first of which performed its maiden flight in 1981 at Groom Lake, Nevada . The first production F-117

3360-527: The Dora Farms in an attempt to assassinate Saddam Hussein . The F-117 was chosen to deliver a bunker buster payload because nearby Baghdad was heavily fortified with anti-aircraft weapons, and US intelligence indicated Saddam Hussein's bunker was too reinforced for missiles. The EGBU-27 Advanced Paveway III bunker buster is an unusual payload for the F-117. Post-facto intelligence showed that Saddam Hussein had been at Dora Farms but left several hours prior to

3456-615: The Northrop T-38A , fly-by-wire systems of the F-16 , landing gear of the A-10 , and environmental systems of the C-130 . By bringing together existing technology and components, Lockheed built two demonstrators under budget, at $ 35 million for both aircraft, and in record time. Undersecretary of Defense for Research and Engineering William J. Perry was instrumental in shepherding

3552-717: The Su-27 'Flanker', the F-15 Eagle , and the F-22 Raptor . The first twinjet to fly was the German fighter prototype Heinkel He 280 , flying in April 1941 with a pair of nacelled Heinkel HeS 8 axial-flow turbojets. The twinjet configuration was used for short-range narrow-bodied aircraft such as the McDonnell Douglas DC-9 and Boeing 737 . The Airbus A300 was initially not successful when first produced as

3648-588: The sound barrier would produce an obvious sonic boom , and surface heating of the aircraft skin would also increase the infrared footprint. As a result, its performance in air combat maneuvering required in a dogfight would never match that of a dedicated fighter aircraft; this was unimportant in the case of the F-117 since it was a dedicated attack aircraft. Passive (multistatic) radar , bistatic radar and especially multistatic radar systems detect some stealth aircraft better than conventional monostatic radars , since first-generation stealth technology (such as

3744-753: The 777-200LR variant has the world's second longest aircraft range (behind Airbus A350-900 ULR). Other Boeing twinjets include the 767 , 757 (With the latter having stopped production, but still in commercial service) and 787 . Competitor Airbus produces the A320 family , the A330 , and the A350 . Some modern commercial airplanes still use four engines ( quad-jets ) like the Airbus A380 and Boeing 747-8 , which are classified as very large aircraft (over 400 seats in mixed-class configurations). Four engines are still used on

3840-432: The 777X, with a composite structure for an operating empty weight of 467,400 lb (212 t), and a 8,150 nmi (15,090 km) range at Mach 0.85. When flying far from diversionary airports (so called ETOPS/LROPS flights), the aircraft must be able to reach an alternate on the remaining engine within a specified time in case of one engine failure. When aircraft are certified according to ETOPS standards, thrust

3936-411: The A300 as a medium- to long-range airliner to increased sales; Boeing launched its widebody twinjet, the Boeing 767 , in response. In the 1980s the Boeing 727 was discontinued, as its central engine bay would require a prohibitively expensive redesign to accommodate quieter high-bypass turbofans, and it was soon supplanted by twinjets for the narrow-body market; Airbus with the A320 , and Boeing with

Lockheed F-117 Nighthawk - Misplaced Pages Continue

4032-615: The Air Dominance Center in Savannah, Georgia. It was a joint exercise with both active USAF and Air National Guard units. In a video documenting the exercise, an off-screen crew member stated that there are approximately 48 flyable F-117s in USAF inventory. They stated that the F-117 is sometimes used in aggressor-type training roles and was brought to Savannah Sentry to participate in an "unclassified capacity." On 1 February 2024, two F-117s were seen at testing range R-2508 in

4128-637: The Defense Ministry, Moscow , Soviet Union , in 1959 and his Dr. Sc. degree in theoretical and mathematical physics from St. Petersburg University , St. Petersburg , Soviet Union , in 1970. While working in Moscow, Ufimtsev became interested in describing the reflection of electromagnetic waves. He gained permission to publish his research results internationally because they were considered to be of no significant military or economic value. A stealth engineer at Lockheed, Denys Overholser, had read

4224-620: The F-111. Soviet fighters obtained by the U.S. via various means under the Constant Peg program 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. 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

4320-626: The F-117 is aerodynamically unstable in all three aircraft principal axes and requires constant flight corrections from a fly-by-wire (FBW) flight system to maintain controlled flight. It is equipped with quadruple-redundant fly-by-wire flight controls. To lower development costs, the avionics, fly-by-wire systems, and other systems and parts were derived from the General Dynamics F-16 Fighting Falcon , Boeing B-52 Stratofortress , McDonnell Douglas F/A-18 Hornet , and McDonnell Douglas F-15E Strike Eagle . To maintain

4416-432: The F-117 is limited to subsonic speeds. Additionally, to maintain its low observability, the F-117 was not equipped with radar; not only would an active radar be detectable through its emissions, but an inactive radar antenna would also act as a reflector of radar energy. Whether it carries any radar detection equipment remained classified as of 2008. Its faceted shape (made from two-dimensional flat surfaces) resulted from

4512-660: The F-117 was publicly acknowledged for the first time. Its first combat mission was flown during the United States invasion of Panama in 1989. The last of 59 production F-117s were delivered on 3 July 1990. The F-117 was widely publicized for its role in the Gulf War of 1991, having flown approximately 1,300 sorties and scored direct hits on what the US military described as 1,600 high-value targets in Iraq. F-117s also participated in

4608-513: The F-117's effectiveness were later found to be overstated. Initial reports of F-117s hitting 80% of their targets were later scaled back to "41–60%". On the first night, they failed to hit 40% of their assigned air-defense targets, including the Air Defense Operations Center in Baghdad, and 8 such targets remained functional out of 10 that could be assessed. In their Desert Storm white paper, the USAF stated that "the F-117

4704-460: The F-117) reflects energy away from the transmitter's line of sight , effectively increasing the radar cross section (RCS) in other directions, which the passive radars monitor. During the program's early years, from 1984 to mid-1992, the F-117 fleet was based at Tonopah Test Range Airport , Nevada, where it served under the 4450th Tactical Group ; Air Combat Command 's only F-117A unit. The unit

4800-506: The F-117; they avoided the optically aimed anti-aircraft cannon and infrared SAMs which were the biggest threat to Coalition aircraft. The F-117 was used during Operation Enduring Freedom in 2001. The Taliban lacked a modern Air Force. After the initial bombing campaign in October, targets justifying F-117 usage were limited as was the use of the F-117. The first bombs dropped in the 2003 Operation Iraqi Freedom were from two F-117 on

4896-575: The F-117s were placed in "Type 1000" storage in their original hangars at the Tonopah Test Range Airport . At Tonopah, their wings were removed and the aircraft are stored in their original climate-controlled hangars. The decommissioning occurred in eight phases, with the operational aircraft retired to Tonopah in seven waves from 13 March 2007 until the last wave's arrival on 22 April 2008. Four aircraft were kept flying beyond April by

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4992-736: The Joint Advanced Strike Technology program, which evolved into the Joint Strike Fighter . The F-117N would have differed from the land-based F-117 in several ways, such as the use of "elevators, a bubble canopy, a less sharply swept wing and reconfigured tail". It would also be re-engined with General Electric F414 turbofans in place of the General Electric F404s . The aircraft would be optionally fitted with hardpoints, allowing for an additional 8,000 lb (3,600 kg) of payload, and

5088-646: The Mojave Desert. The United States Navy tested the F-117 in 1984 but determined it was unsuitable for carrier use. In the early 1990s, Lockheed proposed an upgraded carrier-capable F-117 variant dubbed the "Seahawk" to the Navy as an alternative to the canceled A/F-X program. The unsolicited proposal was received poorly by the Department of Defense, which lacked interest in the single mission capabilities on offer, particularly as it would take money away from

5184-410: The Physical Theory of Diffraction (2007, 2014). With appropriate modifications, PTD can be employed for the solution to many practical problems. Among them are the design of microwave antennas, mobile radio communication, construction of acoustic barriers to decrease a noise level, evaluation of radar cross sections for large objects (tanks, ships, missiles, etc.). Dr. Ufimtsev has been affiliated with

5280-559: The U.S. called 1,600 high-value targets in Iraq over 6,905 flight hours. Leaflet drops on Iraqi forces displayed the F-117 destroying ground targets and warned "Escape now and save yourselves". Only 229 Coalition tactical aircraft could drop and designate laser-guided bombs of which 36 F-117s represented 15.7%, and only the USAF had the I-2000 bombs intended for hardened targets. So the F-117 represented 32% of all coalition aircraft that could deliver such bombs. Notably, F-117s were involved in

5376-471: 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." The operational aircraft was officially designated "F-117A". Most modern U.S. military aircraft use post-1962 designations in which

5472-445: The aircraft as "none of their business, a stand-alone system". The F-117 and the men and women of the 49th Fighter Wing were deployed to Southwest Asia on multiple occasions. On their first deployment, with the aid of aerial refueling, pilots flew non-stop from Holloman to Kuwait, a flight of approximately 18.5 hours. One F-117 (AF ser. no. 82-0806) was lost to enemy action. It was downed during an Operation Allied Force mission against

5568-411: The aircraft), F-117A was the designation printed on the cover. When the USAF first approached Lockheed with the stealth concept, Skunk Works Director Kelly Johnson proposed a rounded design. He believed smoothly blended shapes offered the best combination of speed and stealth. However, his assistant, Ben Rich, showed that faceted-angle surfaces would provide a significant reduction in radar signature, and

5664-599: The bombing. During this time the Air Force estimated the operational cost as $ 35,000 per JDAM style bomb delivered by the F-117. The loss of an F-117 in Serbia caused the USAF to create a subsection of their existing weapons school to improve tactics. More training was done with other units, and the F-117 began to participate in Red Flag exercises . Though advanced for its time, the F-117's stealthy faceted airframe required

5760-432: The book: P. Ya. Ufimtsev, Method of Edge Waves in the Physical Theory of Diffraction , Soviet Radio, Moscow, 1962. In 1971 this book was translated into English with the same title by U.S. Air Force, Foreign Technology Division (National Air and Space Intelligence Center) , Wright-Patterson AFB, OH, 1971. Technical Report AD 733203, Defense Technical Information Center of USA, Alexandria VA. This theory played

5856-418: The command of Colonel Zoltán Dani . After the explosion, the aircraft became uncontrollable, forcing the pilot to eject. The pilot was recovered six hours later by a United States Air Force Pararescue team. The stealth technology from the downed F-117 has reportedly been studied by Russia, and possibly China. The U.S. did not attempt to destroy the wreckage; senior Pentagon officials claimed that its technology

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5952-578: The command of the 49th Fighter Wing . The F-117 reached initial operating capability status in 1983. The Nighthawk's pilots called themselves "Bandits". Each of the 558 Air Force pilots who have flown the F-117 has a Bandit number, such as "Bandit 52", that indicates the sequential order of their first flight in the F-117. Pilots told friends and families that they flew the Northrop F-5 in aggressor squadrons against Tactical Air Command. The F-117 has been used several times in war. Its first mission

6048-649: The concept of aircraft with reduced radar signatures. Ufimtsev was born into a peasant family in the village of Ust-Charysh Pristan , in the Altai region, West Siberian Krai (now Altai Krai ) of the RSFSR of the former USSR . At the age of three his father was repressed by the regime and later died in a gulag . He received his Ph.D. degree in electrical engineering from the Central Research Radio Engineering Institute of

6144-560: The conflict in Yugoslavia , during which one was shot down by a surface-to-air missile (SAM) in 1999. It was also active during Operation Enduring Freedom in 2001 and Operation Iraqi Freedom in 2003. The USAF retired the F-117 in 2008, primarily due to the fielding of the F-22 Raptor . Despite the type's official retirement, a portion of the fleet has been kept in airworthy condition, and F-117s have been observed flying since being retired from combat. In 1936, Robert Watson Watt ,

6240-623: 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 F-117 is primarily an attack aircraft, so its "F" designation is inconsistent with the Department of Defense system. This is an inconsistency that has been repeatedly employed by the USAF with several of its attack aircraft since

6336-420: The enigmatic 4477th Test and Evaluation Squadron , also known as the "Red Hats" or "Red Eagles", that often had flown expatriated MiG jet fighters in the area, but there was no relationship to 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

6432-507: The first acknowledgement by the service that the aircraft continued to fly after its official retirement. In January 2022, two F-117s were observed in flight in the Saline Military Operating Area . One had portions of its exterior covered in a "mirror-like coating" believed to be an experimental treatment to reduce the aircraft's infrared signature. In May 2023, an F-117 participated in exercise Savannah Sentry at

6528-430: The gaps between the sheets filled with a kind of putty material called "butter". An exhaust plume contributes a significant infrared signature . The F-117 reduces IR signature with a non-circular tail pipe (a slit shape) to minimize the exhaust cross-section and maximize the mixing of hot exhaust with cool ambient air. The F-117 lacks afterburners, because the hot exhaust would increase the infrared signature, breaking

6624-449: The largest cargo aircraft capable of transporting outsize cargo , including strategic airlifters . Twin-jets tend to be more fuel-efficient than trijet (three engine) and quad-jet (four engine) aircraft. As fuel efficiency in airliners is a high priority, many airlines have been increasingly retiring trijet and quad-jet designs in favor of twinjets in the twenty-first century. The trijet designs were phased out first, in particular due to

6720-509: 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

6816-467: The limitations of the 1970s-era computer technology used to calculate its RCS. Later supercomputers made it possible for subsequent aircraft like the B-2 bomber to use curved surfaces while maintaining stealth, through the use of far more computational resources to perform the additional calculations. The radar-absorbent flat sheets covering the F-117 weighed almost one ton, and were held in place by glue, with

6912-614: The many inaccurate rumors about the shape of the "F-19". 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. In April 1990, two F-117s flew to Nellis, arriving during daylight and publicly displayed to a crowd of tens of thousands. Five Full Scale Development (FSD) aircraft were built, designated "YF-117A". The last of 59 production F-117s were delivered on 3 July 1990. As

7008-428: The max rate of climb is 2,820 feet (860 m) per minute, and service ceiling is 43,000 to 45,000 feet (13,000 to 14,000 m). The cockpit was quite spacious, with ergonomic displays and controls, but the field of view was somewhat obstructed with a large blind spot to the rear. Early stealth aircraft were designed with a focus on minimal radar cross-section (RCS) rather than aerodynamic performance; because of this,

7104-410: The more complicated design and maintenance issues of the middle engine mounted on the stabilizer. Early twinjets were not permitted by ETOPS restrictions to fly long-haul trans-oceanic routes, as it was thought that they were unsafe in the event of failure of one engine, so quad-jets were used. Quad-jets also had higher carrying capacity than comparable earlier twinjets. However, later twinjets such as

7200-413: The necessary aerodynamic control could be provided with computer units. A May 1975 Skunk Works report, "Progress Report No. 2, High Stealth Conceptual Studies", showed the rounded concept that was rejected in favor of the flat-sided approach. The resulting unusual design surprised and puzzled experienced pilots; a Royal Air Force (RAF) pilot who flew it as an exchange officer stated that when he first saw

7296-586: The program code name " 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 . The program was led by Ben Rich , with Alan Brown as manager of the project. Rich called on Bill Schroeder, a Lockheed mathematician, and Overholser, a mathematician and Radar Specialist, to exploit Ufimtsev's work. The three designed

7392-468: The project. The maiden flight of the demonstrators occurred on 1 December 1977. Although both aircraft crashed during the demonstration program, test data gathered proved positive. 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

7488-472: The publication and realized that Ufimtsev had created the mathematical theory and tools to do finite element analysis of radar reflection. This discovery inspired and had a role in the design of the first true stealth aircraft, the Lockheed F-117 . Northrop also used Ufimtsev's work to program super computers to predict the radar reflection of the B-2 bomber. In the 1960s Ufimtsev began developing

7584-463: The radar return from an object is related to its edge configuration, not its size. Ufimtsev was extending theoretical work published by the German physicist Arnold Sommerfeld . 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,

7680-738: The requirement that an aircraft be able to continue a takeoff if an engine fails after the takeoff decision speed is reached. Thus, with all engines operating, trijets must be able to produce at least 150% of the minimum thrust required to climb and quad-jets 133%. Conversely, since a twinjet will lose half of its total thrust if an engine fails, they are required to produce 200% of the minimum thrust required to climb when both engines are operating. Because of this, twinjets typically have higher thrust-to-weight ratios than aircraft with more engines, and are thus able to accelerate and climb faster. Pyotr Ufimtsev Pyotr (Petr) Yakovlevich Ufimtsev ( Russian : Пётр Я́ковлевич Уфи́мцев ; born 1931)

7776-404: The resulting design would make the aircraft 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 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

7872-424: 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. 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

7968-450: The way. On large passenger jets, the cost of the engines makes up a significant proportion of the plane's final cost. Each engine also requires separate service, paperwork, and certificates. Having two larger engines as opposed to three or four smaller engines will typically significantly reduce both the purchase and maintenance costs of a plane. Regulations governing the required thrust levels for transport aircraft are typically based upon

8064-520: Was a black project , remaining an ultra-secret program for much of its life. The project began in 1975 with a model called the "Hopeless Diamond" (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 " Have Blue ". These subscale aircraft incorporated jet engines of

8160-430: Was already dated and no longer important to protect. American sources state that a second F-117 was targeted and damaged during the campaign, allegedly on 30 April 1999. The aircraft returned to Spangdahlem Air Base , but it supposedly never flew again. The USAF continued using the F-117 during Operation Allied Force. During the Gulf War in 1991, the F-117 flew approximately 1,300 sorties and scored direct hits on what

8256-499: Was delivered in 1982, and its initial operating capability was achieved in October 1983. All aircraft were initially based at Tonopah Test Range Airport , Nevada. The aircraft's faceted shape (made from two-dimensional flat surfaces) heavily contributes to its relatively low radar cross-section of about 0.001 m (0.0108 sq ft). To minimize its infrared signature , it has a non-circular tail pipe that mixes hot exhaust with cool ambient air and lacks afterburners ; it

8352-448: Was delivered in 1982, and operational capability was achieved in October 1983. The 4450th Tactical Group stationed at Nellis Air Force Base , Nevada , were tasked with the operational development of the early F-117, and between 1981 (prior to the arrival of the first models) and 1989 they used LTV A-7 Corsair IIs for training, to bring all pilots to a common flight training baseline and later as chase planes for F-117A tests. The F-117

8448-494: Was during the United States invasion of Panama in 1989. During that invasion, at least two F-117s dropped bombs on Rio Hato airfield. The aircraft was operated in secret from Tonopah for almost a decade, after the Gulf War, all aircraft moved to Holloman in 1992—however, its integration with the USAF's non-stealth "iron jets" occurred slowly. As one senior F-117 pilot later said: Because of ongoing secrecy others continued to see

8544-478: 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. However, there were no other aircraft to receive a "100" series number following

8640-473: Was headquartered at Nellis Air Force Base . A-7 Corsair II aircraft were used for training. Most personnel and their families lived in Las Vegas. This required commercial air and trucking to transport personnel between Las Vegas and Tonopah each week. 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 , under

8736-487: Was highly effective at destroying military targets. Post war records show that the F-117 had 18 times more targets per aircraft than their non-stealthy peers. Outside of Baghdad, the F-117 bombing was primarily used to destroy airfields, and it was used in conjunction with other air munitions. Overall, 42 F-117s dropped 2077 bombs in Desert Storm. This accounts for about a third of USAF guided bombing. Early claims of

8832-587: Was scrapped at the Palmdale test facility on 26 April 2008. It was the last F-117 at Palmdale and was scrapped to test an effective method for destroying these planes. Congress had ordered that all F-117s mothballed from 30 September 2006 onwards were to be maintained "in a condition that would allow recall of that aircraft to future service" as part of the 2007 National Defense Authorization Act . As of 2022, USAF plans to demilitarize three F-117s each year until 2034 when they should all be demilitarized. The USAF

8928-611: 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 . Armed guards prohibited entry, including firefighters, and a helicopter gunship circled

9024-755: Was set for the development of a stealth airplane. The F-117 was conceived after the Vietnam War , where increasingly sophisticated Soviet surface-to-air missiles (SAMs) had downed heavy bombers. The heavy losses inflicted by Soviet-made SAMs upon the Israeli Air Force in the 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. It

9120-399: Was the only airplane that the planners dared risk over downtown Baghdad" and that this area was particularly well defended. (Dozens of F-16s were routinely tasked to attack Baghdad in the first few days of the war.) In fact, most of the air defenses were on the outskirts of the city and many other aircraft hit targets in the downtown area, with minimal casualties when they attacked at night like

9216-523: Was vital. The USAF had once planned to retire the F-117 in 2011, but Program Budget Decision 720 (PBD 720), dated 28 December 2005, proposed retiring it by October 2008 to free up an estimated $ 1.07 billion to buy more F-22s. PBD 720 called for 10 F-117s to be retired in FY2007 and the remaining 42 in FY2008, stating that other USAF planes and missiles could stealthily deliver precision ordnance, including

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