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Lockheed F-117 Nighthawk

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 was commenced in the 1970s as a means of countering increasingly sophisticated Soviet surface-to-air missiles (SAMs). During 1976, 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 during 1981 at Groom Lake, Nevada. The first production F-117 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 m2. To minimize its infrared signature, it has a non-circular tail pipe that mixes hot exhaust with cool ambient air and lacks afterburners; it 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 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 years following its entry to service, the F-117 was a black project, its existence being denied by USAF officials. On 10 November 1988, 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 called 1,600 high-value targets in Iraq. F-117s also participated in 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.

Background and Have Blue
In 1936, Robert Watson Watt, 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 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, 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 was set for the development of a stealth airplane.

The F-117 was born 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 was a black project, an ultra-secret program for much of its life; very few people in the Pentagon knew the program even existed. 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 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 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 the program code name "Senior Trend".

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 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 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 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 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 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 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."

Designation
The operational aircraft was officially designated "F-117A". 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 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 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.

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. However, there were no other aircraft 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 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 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 the aircraft), F-117A was the designation printed on the cover.

Design

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 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 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 stealthy aircraft, such as to have a cooler operational temperature, and somewhat resembled a turbojet instead. The engine was redesigned to produce 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 at high altitude, the max rate of climb is 2820 ft per minute, and service ceiling is 43000 to 45000 ft. 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.

Avionics
Early stealth aircraft were designed with a focus on minimal radar cross-section (RCS) rather than aerodynamic performance; because of this, 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 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 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 5000 lb 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.

Stealth
The F-117 has a radar cross-section (RCS) of about 0.001 m2. 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, 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 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 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 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 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.

Early activities

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 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 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 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 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.

Yugoslavia

One F-117 (AF ser. no. 82-0806) was lost to enemy action. It was the first ever shootdown of a stealth technology airplane. It was downed during an Operation Allied Force mission against the Army of Yugoslavia on 27 March 1999. The aircraft was acquired by a fire control radar at a distance of 13 km and an altitude of 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 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 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.

Iraq and Afghanistan
During the Gulf War in 1991, the F-117 flew approximately 1,300 sorties and scored direct hits on what 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 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 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 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 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 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 the Dora Farms in 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 the bombing. During this time the Air Force estimated the operational cost as $35,000 per JDAM style bomb delivered by the F-117.

Program closeout
The loss 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 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 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 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 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 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 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 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 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.

Post-retirement service
The service is 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, 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-15C/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, 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 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 the Mojave Desert.

F-117N "Seahawk"
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 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 8000 lb of payload, and 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.

F-117B
After being rebuffed by the Navy, Lockheed submitted an updated proposal that included afterburning capability and a larger emphasis on the F-117N as a multi-mission aircraft, rather than just an attack aircraft. To boost interest, Lockheed also proposed an F-117B land-based variant that shared most of the F-117N capabilities. This variant was proposed to the USAF and RAF. Two RAF pilots formally evaluated the aircraft in 1986 as a reward for British help with the American bombing of Libya that year. RAF exchange officers began flying the F-117 in 1987, but the British declined an offer during the Reagan administration to purchase the aircraft. This renewed F-117N proposal was also known as the A/F-117X. Neither the F-117N nor the F-117B were ordered.

Operators

Source: f117sfa.org
 * United States
 * United States Air Force
 * 4450th Tactical Group – Tonopah Test Range, Nevada
 * 4450th Tactical Squadron (1981–1989)
 * 4451st Tactical Squadron (1981–1989)
 * 4453rd Test and Evaluation Squadron (1985–1989)
 * 37th Tactical Fighter Wing/Fighter Wing – Tonopah Test Range
 * 415th Tactical Fighter Squadron (1989–1992)
 * 416th Tactical Fighter Squadron (1989–1992)
 * 417th Tactical Fighter Training Squadron (1989–1992)
 * 49th Fighter Wing – Holloman AFB, New Mexico
 * 7th Fighter Squadron (1992–2006)
 * 8th Fighter Squadron (1992–2008)
 * 9th Fighter Squadron (1993–2008)
 * 412th Test Wing – Edwards AFB, California
 * 410th Flight Test Squadron (1993–2008)

United States

 * YF-117A
 * 79-10780 Scorpion 1 – on pedestal display on Nellis Boulevard, at the entrance to Nellis Air Force Base, Nevada (36.22722°N, -115.05924°W). It was put in place on 16 May 1992, the first F-117 to be made a gate guardian.
 * 79-10781 Scorpion 2 – National Museum of the United States Air Force at Wright-Patterson Air Force Base outside Dayton, Ohio. It was delivered to the museum on 17 July 1991.
 * 79-10782 Scorpion 3 – Holloman Air Force Base, New Mexico. It was repainted to resemble the first F-117A used to drop weapons in combat. This aircraft was used for acoustics and navigation system testing. While wearing a flag painted on its bottom surface, this aircraft revealed the type's existence to high-ranking officials at Groom Lake on 14 December 1983, the first semi-public unveiling of the aircraft. It was placed on display at Holloman AFB on 5 April 2008.
 * 79-10783 Scorpion 4 – It had been previously on display at the Blackbird Airpark Museum at Air Force Plant 42, Palmdale, California. In June 2012, Scorpion 4 was transported from Blackbird Airpark to Edwards AFB for restoration work; it is planned for the aircraft to be displayed at the Air Force Flight Test Museum.

 * F-117A
 * 80-0785 – Pole-mounted outside the Skunk Works facility at United States Air Force Plant 42 in Palmdale, California. Hybrid airframe comprising the wreckage of 80–0785, the first production F-117A, and static test articles 778 and 779. It is fixed to a pedestal and serves as a monument.
 * 81-0794 Delta Dawn - Museum of Aviation (Warner Robins); aircraft arrived at the museum on 18 May 2023; it is to be partially restored and put on display.
 * 82-0799 Midnight Rider – Hill Aerospace Museum; Aircraft arrived at the museum on 5 August 2020; it is to be prepared and painted for display.
 * 82-0803 Unexpected Guest – Displayed outside the Ronald Reagan Presidential Library in Simi Valley, California. It was fixed to a pedestal and became a monument.
 * 84-0810 Dark Angel – On 13 November 2022 it was reported on social media that the airframe was being delivered from Tonopah Test Range to the Pima Air & Space Museum.
 * 85-0813 The Toxic Avenger – Delivered to Castle Air Museum in Atwater, California on 29 July 2022 for restoration and then display. Restoration is expected to take about a year and cost around $75,000.
 * 85-0816 Lone Wolf - Evergreen Aviation & Space Museum, McMinnville, Oregon, undergoing restoration. It was the first F-117 to drop a bomb during Operation Desert Storm.
 * 85-0817 Shaba – Arrived at the Kalamazoo Air Zoo on 11 December 2020. Restoration completed and put on display July 2022.
 * 85-0819 Raven Beauty – Arrived at the Stafford Air & Space Museum July 11, 2024 for preservation. It will be available for public display 24 July 2024.
 * 84-0827 – Stripped fuselage listed as "scrap" on a government surplus website in early 2020. Fate unknown.
 * 85-0831 – Located at the Strategic Air Command & Aerospace Museum in Ashland, Nebraska, where it is scheduled for restoration and display. It served as a test aircraft at Air Force Plant 42 in Palmdale, California from 1987 to 2008.
 * 85-0833 Black Devil – Unveiled at Palm Springs Air Museum on 3 October 2020. Now on display following a period of restoration.

Serbia

 * F-117A
 * 82-0806 Something Wicked – shot down over Serbia; the remains are displayed at the Museum of Aviation in Belgrade close to Belgrade Nikola Tesla Airport.

Nicknames
The aircraft's official name is "Night Hawk", with the alternative form "Nighthawk" also used.

As it prioritized stealth over aerodynamics, it earned the nickname "Wobblin' Goblin" due to its alleged instability at low speeds. However, F-117 pilots have stated the nickname is undeserved. "Wobblin' (or Wobbly) Goblin" is 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. During Operation Desert Storm, Saudis dubbed the aircraft "Shaba", which is Arabic for "Ghost". Some pilots also called the airplane the "Stinkbug".

During the NATO bombing of Yugoslavia in 1999 it picked up the nickname "Invisible" (Serbian Cyrillic "Невидљиви", Latin "Nevidljivi"). The name became ironic after it was shot down over Serbian airspace near Buđanovci, leading to the phrase "we didn't know it was invisible".

Notable appearances in media
The Omaha Nighthawks professional American football team used the F-117 Nighthawk as its logo.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Lockheed F-117 Nighthawk


text:
Vought F4U Corsair

The Vought F4U Corsair is an American fighter aircraft that saw service primarily in World War II and the Korean War. Designed and initially manufactured by Chance Vought, the Corsair was soon in great demand; additional production contracts were given to Goodyear, whose Corsairs were designated FG, and Brewster, designated F3A.

The Corsair was designed and operated as a carrier-based aircraft, and entered service in large numbers with the U.S. Navy in late 1944 and early 1945. It quickly became one of the most capable carrier-based fighter-bombers of World War II. Some Japanese pilots regarded it as the most formidable American fighter of World War II and its naval aviators achieved an 11:1 kill ratio. Early problems with carrier landings and logistics led to it being eclipsed as the dominant carrier-based fighter by the Grumman F6F Hellcat, powered by the same Double Wasp engine first flown on the Corsair's initial prototype in 1940. Instead, the Corsair's early deployment was to land-based squadrons of the U.S. Marine Corps and U.S. Navy.

The Corsair served almost exclusively as a fighter-bomber throughout the Korean War and during the French colonial wars in Indochina and Algeria. In addition to its use by the U.S. and British, the Corsair was also used by the Royal New Zealand Air Force, French Naval Aviation, and other air forces until the 1960s.

From the first prototype delivery to the U.S. Navy in 1940, to final delivery in 1953 to the French, 12,571 F4U Corsairs were manufactured in 16 separate models. Its 1942–1953 production run was the longest of any U.S. piston-engined fighter.

Development
In February 1938, the U.S. Navy Bureau of Aeronautics published two requests for proposal for twin-engined and single-engined fighters. For the single-engined fighter, the Navy requested the maximum obtainable speed, and a minimum stalling speed not higher than 70 mph. A range of 1000 mi was specified. The fighter had to carry four guns, or three with increased ammunition. Provision had to be made for antiaircraft bombs to be carried in the wing. These small bombs would, according to thinking in the 1930s, be dropped on enemy aircraft formations.

In June 1938, the U.S. Navy signed a contract with Vought for a prototype bearing the factory designation V-166B, the XF4U-1, BuNo 1443. The Corsair design team was led by Rex Beisel. After mock-up inspection in February 1939, construction of the XF4U-1 powered by an XR-2800-4 prototype of the Pratt & Whitney R-2800 Double Wasp twin-row, 18-cylinder radial engine, rated at 1805 hp went ahead quickly, as the first airframe ever designed from the start to have a Double Wasp engine fitted for flight. When the prototype was completed, it had the biggest and most powerful engine, largest propeller, and probably the largest wing on any naval fighter to date. The first flight of the XF4U-1 was made on 29 May 1940, with Lyman A. Bullard, Jr. at the controls. The maiden flight proceeded normally until a hurried landing was made when the elevator trim tabs failed because of flutter.

On 1 October 1940, the XF4U-1 became the first single-engined U.S. fighter to fly faster than 400 mph by flying at an average ground speed of 405 mph from Stratford to Hartford. The USAAC's twin engine Lockheed P-38 Lightning had flown over 400 mph in January–February 1939. The XF4U-1 also had an excellent rate of climb, although testing revealed some requirements would have to be rewritten. In full-power dive tests, speeds up to 550 mph were achieved, but not without damage to the control surfaces and access panels, and in one case, an engine failure. The spin recovery standards also had to be relaxed, as recovery from the required two-turn spin proved impossible without resorting to an antispin chute. The problems clearly meant delays in getting the design into production.

Reports coming back from the war in Europe indicated an armament of two .30 in synchronized engine cowling-mount machine guns, and two .50 in machine guns (one in each outer wing panel) was insufficient. The U.S. Navy's November 1940 production proposals specified heavier armament. The increased armament comprised three .50 caliber machine guns mounted in each wing panel. This improvement greatly increased the ability of the Corsair to shoot down enemy aircraft.

Formal U.S. Navy acceptance trials for the XF4U-1 began in February 1941. The Navy entered into a letter of intent on 3 March 1941, received Vought's production proposal on 2 April, and awarded Vought a contract for 584 F4U-1 fighters, which were given the name "Corsair" – inherited from the firm's late-1920s Vought O2U naval biplane scout, which first bore the name – on 30 June of the same year. The first production F4U-1 performed its initial flight a year later, on 24 June 1942. It was a remarkable achievement for Vought; compared to land-based counterparts, carrier aircraft are "overbuilt" and heavier, to withstand the extreme stress of deck landings.

Engine considerations
The F4U incorporated the largest engine available at the time, the 2000 hp 18-cylinder Pratt & Whitney R-2800 Double Wasp radial. To extract as much power as possible, a relatively large Hamilton Standard Hydromatic three-blade propeller of 13 ft was used.

Landing gear and wings
To accommodate a folding wing, the designers considered retracting the main landing gear rearward, but for the chord of wing that was chosen, making the landing gear struts long enough to provide ground clearance for the large propeller was difficult. Their solution was an inverted gull wing, which considerably shortened the required length of the struts. The anhedral of the wing's inboard section also permitted the wing and fuselage to meet at the optimum angle for minimizing drag, without using wing-root fairings. The bent wing was heavier and more difficult to construct, however, offsetting these benefits.

The Corsair's aerodynamics were an advance over those of contemporary naval fighters. The F4U was the first U.S. Navy aircraft to feature landing gear that retracted into a fully enclosed wheel well. The landing gear oleo struts—each with its own strut door enclosing it when retracted—rotated through 90° during retraction, with the wheel atop the lower end of the strut when retracted. A pair of rectangular doors enclosed each wheel well, leaving a streamlined wing. This swiveling, aft-retracting landing gear design was common to the Curtiss P-40 (and its predecessor, the P-36), as adopted for the F4U Corsair's main gear and its erstwhile Pacific War counterpart, the Grumman F6F Hellcat. The oil coolers were mounted in the heavily anhedraled inboard section of the wings, alongside the supercharger air intakes, and used openings in the leading edges of the wings, rather than protruding scoops. The large fuselage panels were made of aluminum and were attached to the frames with the newly developed technique of spot welding, thus mostly eliminating the use of rivets. While employing this new technology, the Corsair was also the last American-produced fighter aircraft to feature fabric as the skinning for the top and bottom of each outer wing, aft of the main spar and armament bays, and for the ailerons, elevators, and rudder. The elevators were also constructed from plywood. The Corsair, even with its streamlining and high-speed abilities, could fly slowly enough for carrier landings with full flap deployment of 50°.

Technical issues
In part because of its advances in technology and a top speed greater than existing Navy aircraft, numerous technical problems had to be solved before the Corsair entered service. Carrier suitability was a major development issue, prompting changes to the main landing gear, tail wheel, and tailhook. Early F4U-1s had difficulty recovering from developed spins, since the inverted gull wing's shape interfered with elevator authority. It was also found that the Corsair's left wing could stall and drop rapidly and without warning during slow carrier landings. In addition, if the throttle were suddenly advanced (for example, during an aborted landing) the left wing could stall and drop so quickly that the fighter could flip over with the rapid increase in power. These potentially lethal characteristics were later solved through the addition of a small, 6 in-long stall strip to the leading edge of the outer right wing, just outboard of the gun ports. This allowed the right wing to stall at the same time as the left.

Other problems were encountered during early carrier trials. The combination of an aft cockpit and the Corsair's long nose made landings hazardous for newly trained pilots because of the lack of visibility due to said features. During landing approaches, it was found that oil from the opened hydraulically powered cowl flaps could spatter onto the windscreen, severely reducing visibility, and the undercarriage oleo struts had bad rebound characteristics on landing, allowing the aircraft to bounce down the carrier deck. The first problem was solved by locking the top cowl flaps in front of the windscreen down permanently, then replacing them with a fixed panel. The undercarriage bounce took more time to solve, but eventually a "bleed valve" incorporated in the legs allowed the hydraulic pressure to be released gradually as the aircraft landed. The Corsair was not considered fit for carrier use until the wing stall problems and the deck bounce could be solved.

Meanwhile, the more docile and simpler-to-build F6F Hellcat had begun entering service in its intended carrier-based use. The Navy wanted to standardize on one type of carrier fighter, and the Hellcat, while slower than the Corsair, was considered simpler to land on a carrier by an inexperienced pilot and proved to be successful almost immediately after introduction. The Navy's decision to choose the Hellcat meant that the Corsair was released to the U.S. Marine Corps. With no initial requirement for carrier landings, the Marine Corps deployed the Corsair to devastating effect from land bases. Corsair deployment aboard U.S. carriers was delayed until late 1944, by which time the last of the carrier landing problems, relating to the Corsair's long nose, had been tackled by the British.

Design modifications
Production F4U-1s featured several major modifications from the XF4U-1. A change of armament to six wing-mounted .50 in M2 Browning machine guns (three in each outer wing panel) and their ammunition (400 rounds for the inner pair, 375 rounds for the outer) meant the location of the wing fuel tanks had to be changed. In order to keep the fuel tank close to the center of gravity, the only available position was in the forward fuselage, ahead of the cockpit. Accordingly, as a 237 USgal self-sealing fuel tank replaced the fuselage mounted armament, the cockpit had to be moved back by 32 in and the fuselage lengthened. Later on, different variants of the F4U were given different armaments. While most Corsair variants had the standard armament of six .50 caliber M2 Browning machine guns, some models (like the F4U-1C) were equipped with four 20 millimeter M2 cannons for its main weapon. While these cannons were more powerful than the standard machine guns, they were not favored over the standard loadout. Only 200 models of this particular Corsair model were produced, out of the total 12,571. Other variants were capable of carrying mission specific weapons such as rockets and bombs. The F4U was able to carry up to a total of eight rockets, or four under each wing. It was able to carry up to four thousand pounds of explosive ordnance. This helped the Corsair take on a fighter bomber role, giving it a more versatile role as a ground support aircraft as well as a fighter. In addition, 150 lb of armor plate was installed, along with a 1.5 in bullet-proof windscreen which was set internally, behind the curved Plexiglas windscreen. The canopy could be jettisoned in an emergency, and half-elliptical planform transparent panels, much like those of certain models of the Curtiss P-40, were inset into the sides of the fuselage's turtledeck structure behind the pilot's headrest, providing the pilot with a limited rear view over his shoulders. A rectangular Plexiglas panel was inset into the lower center section to allow the pilot to see directly beneath the aircraft and assist with deck landings. The engine used was the more powerful R-2800-8 (B series) Double Wasp which produced 2,000 hp. On the wings the flaps were changed to a NACA slotted type and the ailerons were increased in span to increase the roll rate, with a consequent reduction in flap span. IFF transponder equipment was fitted in the rear fuselage. These changes increased the Corsair's weight by several hundred pounds.

Performance
The performance of the Corsair was superior to most of its contemporaries. The F4U-1 was considerably faster than the Grumman F6F Hellcat and only 13 mph slower than the Republic P-47 Thunderbolt. All three were powered by the R-2800. But whereas the P-47 achieved its highest speed at 30020 ft with the help of an intercooled turbocharger, the F4U-1 reached its maximum speed at 19900 ft using a mechanically supercharged engine.

Navy testing and release to the U.S. Marine Corps
The U.S. Navy received its first production F4U-1 on 31 July 1942, though getting it into service proved difficult. The framed "birdcage" style canopy provided inadequate visibility for deck taxiing, and the long "hose nose" and nose-up attitude of the Corsair made it difficult to see straight ahead. The enormous torque of the Double Wasp engine also made it a handful for inexperienced pilots if they were forced to bolter. Early Navy pilots called the F4U the "hog", "hosenose", or "bent-wing widow maker".

Carrier qualification trials on the training carrier USS Wolverine and escort carriers USS Core and USS Charger in 1942 found that, despite visibility issues and control sensitivity, the Corsair was "...an excellent carrier type and very easy to land aboard. It is no different than any other airplane." Two Navy units, VF-12 (October 1942) and later VF-17 (April 1943) were equipped with the F4U. By April 1943, VF-12 had successfully completed deck landing qualification.

At the time, the U.S. Navy also had the Grumman F6F Hellcat, which did not have the performance of the F4U, but was a better deck landing aircraft. The Corsair was declared "ready for combat" at the end of 1942, though qualified to operate only from land bases until the last of the carrier qualification issues were worked out. VF-17 went aboard the USS Bunker Hill (CV-17) in late 1943, and the Chief of Naval Operations wanted to equip four air groups with Corsairs by the end of 1943. The Commander, Air Forces, Pacific had a different opinion, stating that "In order to simplify spares problems and also to insure flexibility in carrier operations present practice in the Pacific is to assign all Corsairs to Marines and to equip FightRons [fighter squadrons] on medium and light carriers with Hellcats." VF-12 soon abandoned its aircraft to the Marines. VF-17 kept its Corsairs, but was removed from its carrier, USS Bunker Hill, due to perceived difficulties in supplying parts at sea.

The Marines needed a better fighter than the F4F Wildcat. For them, it was not as important that the F4U could be recovered aboard a carrier, as they usually flew from land bases. Growing pains aside, Marine Corps squadrons readily took to the radical new fighter.

Marine Corps combat

From February 1943 onward, the F4U operated from Guadalcanal and ultimately other bases in the Solomon Islands. A dozen USMC F4U-1s of VMF-124, commanded by Major William E. Gise, arrived at Henderson Field (code name "Cactus") on 12 February. The first recorded combat engagement was on 14 February 1943, when Corsairs of VMF-124 under Major Gise assisted P-40s and P-38s in escorting a formation of Consolidated B-24 Liberators on a raid against a Japanese aerodrome at Kahili. Japanese fighters contested the raid and the Americans got the worst of it, with four P-38s, two P-40s, two Corsairs, and two Liberators lost. No more than four Japanese Zeros were destroyed. A Corsair was responsible for one of the kills, albeit due to a midair collision. The fiasco was referred to as the "Saint Valentine's Day Massacre". Despite the debut, the Marines quickly learned how to make better use of the aircraft and started demonstrating its superiority over Japanese fighters. By May, the Corsair units were getting the upper hand, and VMF-124 had produced the first Corsair ace, Second Lieutenant Kenneth A. Walsh, who would rack up a total of 21 kills during the war. He remembered: "I learned quickly that altitude was paramount. Whoever had altitude dictated the terms of the battle, and there was nothing a Zero pilot could do to change that — we had him. The F4U could outperform a Zero in every aspect except slow speed manoeuvrability and slow speed rate of climb. Therefore you avoided getting slow when combating a Zero. It took time but eventually we developed tactics and deployed them very effectively... There were times, however, that I tangled with a Zero at slow speed, one on one. In these instances I considered myself fortunate to survive a battle. Of my 21 victories, 17 were against Zeros, and I lost five aircraft in combat. I was shot down three times and I crashed one that ploughed into the line back at base and wiped out another F4U."

VMF-113 was activated on 1 January 1943 at Marine Corps Air Station El Toro as part of Marine Base Defense Air Group 41. They were soon given their full complement of 24 F4U Corsairs. On 26 March 1944, while escorting four B-25 bombers on a raid over Ponape, they recorded their first enemy kills, downing eight Japanese aircraft. In April of that year, VMF-113 was tasked with providing air support for the landings at Ujelang. Since the assault was unopposed, the squadron quickly returned to striking Japanese targets in the Marshall Islands for the remainder of 1944.

Corsairs were flown by the "Black Sheep" Squadron (VMF-214, led by Marine Major Gregory "Pappy" Boyington) in an area of the Solomon Islands called "The Slot". Boyington was credited with 22 kills in F4Us (of 28 total, including six in an AVG P-40, although his score with the AVG has been disputed). Other noted Corsair pilots of the period included VMF-124's Kenneth Walsh, James E. Swett, Archie Donahue, and Bill "Casey" Case; VMF-215's Robert M. Hanson and Donald Aldrich; and VF-17's Tommy Blackburn, Roger Hedrick, and Ira Kepford. Nightfighter versions equipped Navy and Marine units afloat and ashore.

One particularly unusual kill was scored by Marine Lieutenant R. R. Klingman of VMF-312 (the "Checkerboards") over Okinawa. Klingman was in pursuit of a Japanese twin-engine aircraft at high altitude when his guns jammed due to the gun lubrication thickening from the extreme cold. He flew up and chopped off the enemy's tail with the big propeller of the Corsair. Despite missing 5 in off the end of his propeller blades, he managed to land safely after this aerial ramming attack. He was awarded the Navy Cross.

At war's end, Corsairs were ashore on Okinawa, combating the kamikaze, and also were flying from fleet and escort carriers. VMF-312, VMF-323, VMF-224, and a handful of others met with success in the Battle of Okinawa.

Field modifications for land-based Corsairs
Since Corsairs were being operated from shore bases, while still awaiting approval for U.S. carrier operations, 965 FG-1As were built as "land planes" without their hydraulic wing folding mechanisms, hoping to improve performance by reducing aircraft weight, with the added benefit of minimizing complexity. (These Corsairs’ wings could still be manually folded. )

A second option was to remove the folding mechanism in the field using a kit, which could be done for Vought and Brewster Corsairs as well. On 6 December 1943, the Bureau of Aeronautics issued guidance on weight-reduction measures for the F4U-1, FG-1, and F3A. Corsair squadrons operating from land bases were authorized to remove catapult hooks, arresting hooks, and associated equipment, which eliminated 48 pounds of unnecessary weight. While there are no data to indicate to what extent these modifications were incorporated, there are numerous photos in evidence of Corsairs, of various manufacturers and models, on islands in the Pacific without tailhooks installed.

Fighter-bomber
Corsairs also served well as fighter-bombers in the Central Pacific and the Philippines. By early 1944, Marine pilots were beginning to exploit the type's considerable capabilities in the close-support role in amphibious landings. Charles Lindbergh flew Corsairs with the Marines as a civilian technical advisor for United Aircraft Corporation in order to determine how best to increase the Corsair's payload and range in the attack role and to help evaluate future viability of single- versus twin-engine fighter design for Vought. Lindbergh managed to get the F4U into the air with 4000 lb of bombs, with a 2000 lb bomb on the centerline and a 1000 lb bomb under each wing. In the course of such experiments, he performed strikes on Japanese positions during the battle for the Marshall Islands.

By the beginning of 1945, the Corsair was a full-blown "mudfighter", performing strikes with high-explosive bombs, napalm tanks, and HVARs. It proved versatile, able to operate everything from Bat glide bombs to 11.75 in Tiny Tim rockets. The aircraft was a prominent participant in the fighting for the Palaus, Iwo Jima and Okinawa.

Navy service
In November 1943, while operating as a shore-based unit in the Solomon Islands, VF-17 reinstalled the tail hooks so its F4Us could land and refuel while providing top cover over the task force participating in the carrier raid on Rabaul. The squadron's pilots landed, refueled, and took off from their former home, Bunker Hill and USS Essex (CV-9) on 11 November 1943.

Twelve USMC F4U-1s arrived at Henderson Field (Guadalcanal) on 12 February 1943. The U.S. Navy did not get into combat with the type until September 1943. The work done by the Royal Navy's FAA meant those models qualified the type for U.S. carrier operations first. The U.S. Navy finally accepted the F4U for shipboard operations in April 1944, after the longer oleo strut was fitted, which eliminated the tendency to bounce. The first US Corsair unit to be based effectively on a carrier was the pioneer USMC squadron VMF-124, which joined Essex in December 1944. They were accompanied by VMF-213. The increasing need for fighter protection against kamikaze attacks resulted in more Corsair units being moved to carriers.

Sortie, kill and loss figures
U.S. figures compiled at the end of the war indicate that the F4U and FG flew 64,051 operational sorties for the U.S. Marines and U.S. Navy through the conflict (44% of total fighter sorties), with only 9,581 sorties (15%) flown from carrier decks. F4U and FG pilots claimed 2,140 air combat victories against 189 losses to enemy aircraft, for an overall kill ratio of over 11:1. While this gave the Corsair the lowest loss rate of any fighter of the Pacific War, this was due in part to operational circumstances; it primarily faced air-to-air combat in the Solomon Islands and Rabaul campaigns (as well as at Leyte and for kamikaze interception), but as operations shifted north and its mission shifted to ground attack the aircraft saw less exposure to enemy aircraft, while other fighter types were exposed to more air combat. Against the best Japanese opponents, the aircraft claimed a 12:1 kill ratio against the Mitsubishi A6M Zero and 6:1 against the Nakajima Ki-84, Kawanishi N1K-J, and Mitsubishi J2M combined during the last year of the war. The Corsair bore the brunt of U.S. fighter-bomber missions, delivering 15,621 ST of bombs during the war (70% of total bombs dropped by U.S. fighters during the war).

Corsair losses in World War II were as follows:
 * Aerial combat: 189
 * Enemy ground and shipboard anti-aircraft fire: 349
 * Operational losses during combat missions: 230
 * Operational losses during non-combat flights: 692
 * Destroyed aboard ships or on the ground: 164

Enhancement for carrier suitability

In the early days of World War II, Royal Navy fighter requirements had been based on cumbersome two-seat designs, such as the fighter/dive-bomber Blackburn Skua (and its turreted derivative the Blackburn Roc) and the fighter/reconnaissance Fairey Fulmar, since it was expected that they would encounter only long-range bombers or flying boats and that navigation over featureless seas required the assistance of a radio operator/navigator. The Royal Navy hurriedly adopted higher-performance single-seat aircraft such as the Hawker Sea Hurricane and the less robust Supermarine Seafire alongside, but neither aircraft had sufficient range to operate at a distance from a carrier task force. The Corsair was welcomed as a more robust and versatile alternative.

In November 1943, the Royal Navy received its first batch of 95 Vought F4U-1s, which were given the designation "Corsair [Mark] I". The first squadrons were assembled and trained on the U.S. East Coast and then shipped across the Atlantic. The Royal Navy put the Corsair into carrier operations immediately. They found its landing characteristics dangerous, suffering a number of fatal crashes, but considered the Corsair to be the best option they had.

In Royal Navy service, because of the limited hangar deck height in several classes of British carrier, many Corsairs had their outer wings "clipped" by 8 in to clear the deckhead. The change in span brought about the added benefit of improving the sink rate, reducing the F4U's propensity to "float" in the final stages of landing.

The Royal Navy developed a number of modifications to the Corsair that made carrier landings more practical. Among these were a bulged canopy (similar to the Malcolm Hood), raising the pilot's seat 7 in, and wiring shut the cowl flaps across the top of the engine compartment, diverting oil and hydraulic fluid spray around the sides of the fuselage. The curved approach used with the Seafire was also adopted for landing Corsairs, ensuring the flight deck was kept in sight as long as possible.

Deployment
The Royal Navy initially received 95 "birdcage" F4U-1s from Vought which were designated Corsair Mk I in Fleet Air Arm service. Next from Vought came 510 "blown-canopy" F4U-1A/-1Ds, which were designated Corsair Mk II (the final 150 equivalent to the F4U-1D, but not separately designated in British use). 430 Brewster Corsairs (334 F3A-1 and 96 F3A-1D), more than half of Brewster's total production, were delivered to Britain as the Corsair Mk III. 857 Goodyear Corsairs (400 FG-1/-1A and 457 FG-1D) were delivered and designated Corsair Mk IV. The Mk IIs and Mk IVs were the only versions to be used in combat.

The Royal Navy cleared the F4U for carrier operations well before the U.S. Navy and showed that the Corsair Mk II could be operated with reasonable success even from escort carriers. It was not without problems; one was excessive wear of the arrester wires, due both to the weight of the Corsair and the understandable tendency of the pilots to stay well above the stalling speed. A total of 2,012 Corsairs were supplied to the United Kingdom.

Fleet Air Arm (FAA) units were created and equipped in the United States, at Quonset Point or Brunswick and then shipped to war theaters aboard escort carriers. The first FAA Corsair unit was 1830 NAS, created on the first of June 1943, and soon operating from HMS Illustrious (87). At the end of the war, 18 FAA squadrons were operating the Corsair. British Corsairs served both in Europe and in the Pacific. The first, and also most important, European operations were the series of attacks (Operation Tungsten) in April, July, and August 1944 on the GERMAN BATTLESHIP Tirpitz, for which Corsairs from HMS Victorious (R38) and HMS Formidable (67) provided fighter cover. It appears the Corsairs did not encounter aerial opposition on these raids.

From April 1944, Corsairs from the British Pacific Fleet took part in several major air raids in South East Asia beginning with Operation Cockpit, an attack on Japanese targets at Sabang island, in the Dutch East Indies.

In July and August 1945, Corsair naval squadrons 1834, 1836, 1841, and 1842 took part in a series of strikes on the Japanese mainland, near Tokyo. These squadrons operated from Victorious and Formidable. On 9 August 1945, days before the end of the war, Corsairs from Formidable attacked Shiogama harbor on the northeast coast of Japan. Royal Canadian Navy Volunteer Reserve pilot, Lieutenant Robert Hampton Gray, of 1841 Squadron was hit by flak but pressed home his attack on the Japanese destroyer escort Amakusa, sinking it with a 1000 lb bomb but crashing into the sea. He was posthumously awarded Canada's last Victoria Cross, becoming the second fighter pilot of the war to earn a Victoria Cross as well as the final Canadian casualty of World War II.

FAA Corsairs originally fought in a camouflage scheme with a Dark Slate Grey/Extra Dark Sea Grey disruptive pattern on top and Sky undersides, but were later painted overall dark blue. As it had become imperative for all Allied aircraft in the Pacific Theater of World War II to abandon all use of any "red devices" in their national insignia — to prevent any chance of misidentification with Japanese military aircraft, all of which bore the circular, all-red Hinomaru insignia (nicknamed a "meatball" by Allied aircrew) that is still in use to this day, the United States removed all areas of red color (specifically removing the red center to the roundel) and removed any sort of national fin/rudder markings, which at that time had seven horizontal red stripes, from the American national aircraft insignia scheme by 6 May 1942. The British did likewise, starting with a simple paintover with white paint, of their "Type C" roundel's red center, at about the time the U.S. Navy removed the red-center from their roundel. Later, a shade of slate gray center color replaced the white color on the earlier roundel. When the Americans starting using the added white bars to either side of their blue/white star roundel on 28 June 1943; SEAC British Corsairs, most all of which still used the earlier blue/white Type C roundel with the red center removed, added similar white bars to either side of their blue-white roundels to emulate the Americans.

In all, out of 18 carrier-based squadrons, eight saw combat, flying intensive ground attack/interdiction operations and claiming 47.5 aircraft shot down.

At the end of World War II, under the terms of the Lend-Lease agreement, the aircraft had to be paid for or to be returned to the U.S. As the UK did not have the means to pay for them, the Royal Navy Corsairs were pushed overboard into the sea in Moreton Bay off Brisbane, Australia.

Royal New Zealand Air Force
Equipped with obsolescent Curtiss P-40s, Royal New Zealand Air Force (RNZAF) squadrons in the South Pacific performed impressively, in particular in the air-to-air role. The American government accordingly decided to give New Zealand early access to the Corsair, especially as it was not initially being used from carriers. Some 424 Corsairs equipped 13 RNZAF squadrons, including No. 14 Squadron RNZAF and No. 15 Squadron RNZAF, replacing Douglas SBD Dauntlesses as well as P-40s. Most of the F4U-1s were assembled by Unit 60 with a further batch assembled and flown at RNZAF Station Hobsonville. In total there were 336 F4U-1s and 41 F4U-1Ds used by the RNZAF during the Second World War. Sixty FG-1Ds arrived late in the war.

The first deliveries of lend-lease Corsairs began in March 1944 with the arrival of 30 F4U-1s at the RNZAF Base Depot Workshops (Unit 60) on the island of Espiritu Santo in the New Hebrides. From April, these workshops became responsible for assembling all Corsairs for the RNZAF units operating the aircraft in the South West Pacific; and a Test and Despatch flight was set up to test the aircraft after assembly. By June 1944, 100 Corsairs had been assembled and test flown. The first squadrons to use the Corsair were 20 and 21 Squadrons on Espiritu Santo, operational in May 1944. The organization of the RNZAF in the Pacific and New Zealand meant that only the pilots and a small staff belonged to each squadron (the maximum strength on a squadron was 27 pilots): squadrons were assigned to several Servicing Units (SUs, composed of 5–6 officers, 57 NCOs, 212 airmen) which carried out aircraft maintenance and operated from fixed locations: hence F4U-1 NZ5313 was first used by 20 Squadron/1 SU on Guadalcanal in May 1944; 20 Squadron was then relocated to 2 SU on Bougainville in November. In all there were ten front line SUs plus another three based in New Zealand. Because each of the SUs painted its aircraft with distinctive markings and the aircraft themselves could be repainted in several different color schemes, the RNZAF Corsairs were far less uniform in appearance than their American and FAA contemporaries. By late 1944, the F4U had equipped all ten Pacific-based fighter squadrons of the RNZAF.

By the time the Corsairs arrived, there were very few Japanese aircraft left in New Zealand's allocated sectors of the Southern Pacific, and despite the RNZAF squadrons extending their operations to more northern islands, they were primarily used for close support of American, Australian, and New Zealand soldiers fighting the Japanese. At the end of 1945, all Corsair squadrons but one (No. 14) were disbanded. That last squadron was based in Japan, until the Corsair was retired from service in 1947.

No. 14 Squadron was given new FG-1Ds and in March 1946 transferred to Iwakuni, Japan as part of the British Commonwealth Occupation Force. Only one airworthy example of the 437 aircraft procured survives: FG-1D NZ5648/ZK-COR, owned by the Old Stick and Rudder Company at Masterton, New Zealand.

Captured Corsairs
On 18 July 1944, a British Corsair (serial JT404) of 1841 Naval Air Squadron, was involved in anti-submarine patrol from HMS Formidable as it returned to Scapa Flow after the Operation Mascot attack on the German battleship Tirpitz. It flew in company with a Fairey Barracuda. Due to technical problems the Corsair made an emergency landing in a field on Hamarøy north of Bodø, Norway. The pilot, Lt Mattholie, was taken prisoner and the aircraft captured undamaged. Luftwaffe interrogators failed to get the pilot to explain how to fold the wings so as to transport the aircraft to Narvik. The Corsair was ferried by boat for further investigation. Later the Corsair was taken to Germany and listed as one of the captured enemy aircraft (Beuteflugzeug) based at Erprobungsstelle Rechlin, the central German military aviation test facility and the equivalent of the Royal Aircraft Establishment, for 1944 under repair. This was probably the only Corsair captured by the Germans.

In 1945, U.S. forces captured an F4U Corsair near the Kasumigaura flight school. The Japanese had repaired it, covering damaged parts on the wing with fabric and using spare parts from crashed F4Us. It seems Japan captured two force-landed Corsairs fairly late in the war and may have tested one in flight.

Korean War

During the Korean War, the Corsair was used mostly in the close-support role. The AU-1 Corsair was developed from the F4U-5 and was a ground-attack version which normally operated at low altitudes: as a consequence the Pratt & Whitney R-2800-83W engine used a single-stage, manually controlled supercharger, rather than the two-stage automatic supercharger of the -5. The versions of the Corsair used in Korea from 1950 to 1953 were the AU-1, F4U-4B, -4P, and -5N and -5NL. There were dogfights between F4Us and Soviet-built Yakovlev Yak-9 fighters early in the war, but when the enemy introduced the Mikoyan-Gurevich MiG-15, the Corsair was outmatched. On 10 September 1952, a MiG-15 made the mistake of getting into a turning contest with a Corsair piloted by Marine Captain Jesse G. Folmar, with Folmar shooting the MiG down with his four 20 mm cannon. In turn, four MiG-15s shot down Folmar minutes later; Folmar bailed out and was quickly rescued with little injury.

F4U-5N and -5NL Corsair night fighters were used to attack enemy supply lines, including truck convoys and trains, as well as interdicting night attack aircraft such as the Polikarpov Po-2 "Bedcheck Charlies", which were used to harass United Nations forces at night. The F4Us often operated with the help of C-47 'flare ships' which dropped hundreds of 1,000,000 candlepower magnesium flares to illuminate the targets. For many operations detachments of U.S. Navy F4U-5Ns were posted to shore bases. The leader of one such unit, Lieutenant Guy Bordelon of VC-3 Det D (Detachment D), off USS Princeton (CV-37), became the Navy's only ace in the war, in addition to being the only American ace in Korea that used a piston engined aircraft. Bordelon, nicknamed "Lucky Pierre", was credited with three Lavochkin La-9s or La-11s and two Yakovlev Yak-18s between 29 June and 16/17 July 1952. Navy and Marine Corsairs were credited with a total of 12 enemy aircraft.

More generally, Corsairs performed attacks with cannons, napalm tanks, various iron bombs, and unguided rockets. The 5 inch HVAR was a reliable standby; sturdy Soviet-built armor proved resistant to the HVAR's punch, which led to a new 6.5 in shaped charge antitank warhead being developed. The result was called the "Anti-Tank Aircraft Rocket (ATAR)." The 11 inch "Tiny Tim" was also used in combat, with two under the belly.

Lieutenant Thomas J. Hudner, Jr., flying an F4U-4 of VF-32 off USS Leyte (CV-32), was awarded the Medal of Honor for crash landing his Corsair in an attempt to rescue his squadron mate, Ensign Jesse L. Brown, whose aircraft had been forced down by antiaircraft fire near Changjin. Brown, who did not survive the incident, was the U.S. Navy's first African American naval aviator.

Aéronavale

After the war, the French Navy had an urgent requirement for a powerful carrier-borne close-air support aircraft to operate from the French Navy's four aircraft carriers that it acquired in the late 1940s (Two former U.S. Navy and two Royal Navy carriers were transferred). Secondhand US Navy Douglas SBD Dauntless dive-bombers of Flotille 3F and 4F were used to attack enemy targets and support ground forces in the First Indochina War. Former US Grumman F6F-5 Hellcats and Curtiss SB2C Helldivers were also used for close air support. A new and more capable aircraft was needed.

First Indochina War
The last production Corsair was the 'F4U-7, which was built specifically for the French naval air arm, the Aéronavale. The XF4U-7 prototype did its test flight on 2 July 1952 with a total of 94 F4U-7s built for the French Navy's Aéronavale (79 in 1952, 15 in 1953), with the last of the batch, the final Corsair built, rolled out on 31 January 1953. The F4U-7s were actually purchased by the U.S. Navy and passed on to the Aéronavale through the U.S. Military Assistance Program (MAP). The French Navy used its F4U-7s during the second half of the First Indochina War in the 1950s (12.F, 14.F, 15.F Flotillas), where they were supplemented by at least 25 ex-USMC AU-1s passed on to the French in 1954, after the end of the Korean War.

On 15 January 1953, Flotille 14F, based at Karouba Air Base near Bizerte in Tunisia, became the first Aéronavale unit to receive the F4U-7 Corsair. Flotille 14F pilots arrived at Da Nang, Vietnam on 17 April 1954, but without their aircraft. The next day, the carrier USS Saipan delivered 25 war-weary ground attack ex-USMC AU-1 Corsairs (flown by VMA-212 at the end of the Korean War) to Tourane Air Base. During three months operating over Vietnam (including in support of the Battle of Dien Bien Phu), the Corsairs flew 959 combat sorties totaling 1,335 flight hours. They dropped some 700 tons of bombs and fired more than 300 rockets and 70,000 20 mm rounds. Six aircraft were damaged and two shot down by Viet Minh.

In September 1954, F4U-7 Corsairs were loaded aboard FRENCH AIRCRAFT CARRIER Dixmude and brought back to France in November. The surviving Ex-USMC AU-1s were taken to the Philippines and returned to the U.S. Navy. In 1956, Flotille 15F returned to South Vietnam, equipped with F4U-7 Corsairs.

Suez Crisis
The 14.F and 15.F Flotillas also took part in the Anglo-French-Israeli seizure of the Suez Canal in October 1956, code-named Operation Musketeer. The Corsairs were painted with yellow and black recognition stripes for this operation. They were tasked with destroying Egyptian Navy ships at Alexandria but the presence of U.S. Navy ships prevented the successful completion of the mission. On 3 November 16 F4U-7s attacked airfields in the Delta, with one Corsair shot down by anti-aircraft fire. Two more Corsairs were damaged when landing back on the carriers. The Corsairs engaged in Operation Musketeer dropped a total of 25 tons of bombs, and fired more than 500 rockets and 16,000 20mm rounds.

Algerian War
As soon as they disembarked from the carriers that took part in Operation Musketeer, at the end of 1956, all three Corsair Flotillas moved to Telergma and Oran airfields in Algeria from where they provided CAS and helicopter escort. They were joined by the new "Flottille 17F", established at Hyères in April 1958.

French F4U-7 Corsairs (with some borrowed AU-1s) of the 12F, 14F, 15F, and 17F Flotillas conducted missions during the Algerian War between 1955 and 1962. Between February and March 1958, several strikes and CAS missions were launched from FRENCH AIRCRAFT CARRIER Bois Belleau, the only carrier involved in the Algeria War.

Tunisia
France recognized Tunisian independence and sovereignty in 1956 but continued to station military forces at Bizerte and planned to extend the airbase. In 1961, Tunisia asked France to evacuate the base. Tunisia imposed a blockade on the base on 17 July, hoping to force its evacuation. This resulted in a battle between militiamen and the French military which lasted three days. French paratroopers, escorted by Corsairs of the 12F and 17F Flotillas, were dropped to reinforce the base and the Aéronavale launched air strikes on Tunisian troops and vehicles between 19–21 July, carrying out more than 150 sorties. Three Corsairs were damaged by ground fire.

French experiments
In early 1959, the Aéronavale experimented with the Vietnam War-era SS.11 wire-guided anti-tank missile on F4U-7 Corsairs. The 12.F pilots trained for this experimental program were required to manually pilot the missile at approximatively two kilometers from the target on low altitude with a joystick using the right hand while keeping track of a flare on its tail, and piloting the aircraft using the left hand; an exercise that could be very tricky in a single-seat aircraft under combat conditions. Despite reportedly effective results during the tests, this armament was not used with Corsairs during the ongoing Algerian War.

The Aéronavale used 163 Corsairs (94 F4U-7s and 69 AU-1s), the last of them used by the Cuers-based 14.F Flotilla were out of service by September 1964, with some surviving for museum display or as civilian warbirds. By the early 1960s, two new modern aircraft carriers, FRENCH AIRCRAFT CARRIER Clemenceau and FRENCH AIRCRAFT CARRIER Foch, had entered service with the French Navy and with them a new generation of jet-powered combat aircraft.

"Football War"
Corsairs flew their final combat missions in 1969 during the "Football War" between Honduras and El Salvador, in service with both air forces. The conflict was allegedly triggered, though not really caused, by a disagreement over a soccer (association football) match. Captain Fernando Soto of the Honduran Air Force shot down three Salvadoran Air Force aircraft on 17 July 1969. In the morning he shot down a Cavalier Mustang, killing the pilot. In the afternoon, he shot down two FG-1s; the pilot of the second aircraft may have bailed out, but the third exploded in the air, killing the pilot. These combats were the last among propeller-driven aircraft in the world and also made Soto the only pilot credited with three kills in an American continental war. El Salvador did not shoot down any Honduran aircraft. At the outset of the Football War, El Salvador enlisted the assistance of several American pilots with P-51 and F4U experience. Bob Love (a Korean war ace), Chuck Lyford, Ben Hall, and Lynn Garrison are believed to have flown combat missions, but it has never been confirmed. Lynn Garrison purchased F4U-7 133693 from the French MAAG office when it was retired from French naval service in 1964. It was registered N693M and was later destroyed in a 1987 crash in San Diego, California.

Legacy
The Corsair entered service in 1942. Although designed as a carrier fighter, initial operation from carrier decks proved to be troublesome. Its low-speed handling was tricky due to the left wing stalling before the right wing. This factor, together with poor visibility over the long nose (leading to one of its nicknames, "The Hose Nose"), made landing a Corsair on a carrier a difficult task. For these reasons, most Corsairs initially went to Marine Corps squadrons which operated off land-based runways, with some early Goodyear-built examples (designated FG-1A) being built with fixed wings. The USMC aviators welcomed the Corsair with open arms as its performance was far superior to the contemporary Brewster F2A Buffalo and Grumman F4F-3 and -4 Wildcat.

Moreover, the Corsair was able to outperform the primary Japanese fighter, the A6M Zero. While the Zero could outturn the F4U at low speed, the Corsair was faster and could outclimb and outdive the A6M.

This performance advantage, combined with the ability to take severe punishment, meant a pilot could place an enemy aircraft in the killing zone of the F4U's six .50 (12.7 mm) M2 Browning machine guns and keep him there long enough to inflict major damage. The 2,300 rounds carried by the Corsair gave just under 30 seconds of fire from each gun.

Beginning in 1943, the Fleet Air Arm also received Corsairs and flew them successfully from Royal Navy carriers in combat with the British Pacific Fleet and in Norway. These were clipped-wing Corsairs, the wingtips shortened 8 in to clear the lower overhead height of RN carriers. FAA also developed a curving landing approach to overcome the F4U's deficiencies.

Infantrymen nicknamed the Corsair "The Sweetheart of the Marianas" and "The Angel of Okinawa" for its roles in these campaigns. Among Navy and Marine aviators, the aircraft was nicknamed "Ensign Eliminator" and "Bent-Wing Eliminator" because it required many more hours of flight training to master than other Navy carrier-borne aircraft. It was also called simply "U-bird" or "Bent Wing Bird". Although Allied World War II sources frequently make the claim that the Japanese called the Corsair the "Whistling Death", Japanese sources do not support this, and it was mainly known as the Sikorsky.

The Corsair has been named the official aircraft of Connecticut due to its multiple connections to Connecticut businesses including airframe manufacturer Vought-Sikorsky Aircraft, engine manufacturer Pratt & Whitney and propeller manufacturer Hamilton Standard.

Variants
During World War II, Corsair production expanded beyond Vought to include Brewster and Goodyear models. Allied forces flying the aircraft in World War II included the Fleet Air Arm and the Royal New Zealand Air Force. Eventually, more than 12,500 F4Us were built, comprising 16 separate variants.

F4U-1 (called Corsair Mk I by the Fleet Air Arm ):

The first production version of the Corsair with the distinctive "birdcage" canopy and low seating position. The differences over the XF4U-1 were as follows:
 * Six .50 in Browning AN/M2 machine guns were fitted in the outer wing panels, displacing fuel tanks.
 * An enlarged 237 USgal fuel tank was fitted ahead of the cockpit, in place of the fuselage armament. The cockpit was moved back by 32 in.
 * The fuselage was lengthened by 1 ft.
 * The more powerful R-2800-8 Double Wasp was fitted.
 * 150 lb of armor plate was fitted to the cockpit and a 1.5 in thick bullet-resistant glass panel was fitted behind the curved windscreen.
 * IFF transponder equipment was fitted.
 * Curved transparent panels were incorporated into the fuselage behind the pilot's headrest.
 * The flaps were changed from deflector type to NACA slotted.
 * The span of the ailerons was increased while that of the flaps was decreased.
 * One 62 USgal auxiliary fuel cell (not a self-sealing type) was installed in each wing leading edge, just outboard of the guns.

The Royal Navy's Fleet Air Arm received 95 Vought F4U-1s. These were all early "birdcage" Corsairs. Vought also built a single F4U-1 two-seat trainer; the Navy showed no interest.

F4U-1A (called Corsair Mk II by the Fleet Air Arm ): Mid-to-late production Corsairs incorporated a new, taller, wider canopy with only two frames — very close to what the Malcolm hood did for British fighter aircraft — along with a simplified windscreen; the new canopy design allowed the semi-elliptical turtledeck "flank" windows to be omitted. The designation F4U-1A to differentiate these Corsairs from earlier "birdcage" variants was allowed to be used internally by manufacturers. The pilot's seat was raised 7 in which, combined with the new canopy and a 6 in lengthening of the tailwheel strut, allowed the pilot better visibility over the long nose. In addition to these changes, the bombing window under the cockpit was omitted. These Corsairs introduced a 6 in-long stall strip just outboard of the gun ports on the right wing leading edge and improved undercarriage oleo struts which eliminated bouncing on landing, making these the first truly "carrier capable" F4Us.

Three hundred and sixty F4U-1As were delivered to the Fleet Air Arm. In British service, they were modified with "clipped" wings (8 in was cut off each wingtip) for use on British aircraft carriers, although the Royal Navy had been successfully operating the Corsair Mk I since 1 June 1943 when 1830 Naval Air Squadron was commissioned and assigned to HMS Illustrious. F4U-1s in many USMC squadrons had their arrester hooks removed. Additionally, an experimental R-2800-8W engine with water injection was fitted on one of the late F4U-1As. After satisfactory results, many F4U-1As were fitted with the new powerplant. The aircraft carried 237 USgal in the main fuel tank, located in front of the cockpit, as well as an unarmored, non-self-sealing 62 USgal fuel tank in each wing. This version of the Corsair was the first to be able to carry a drop tank under the center-section. With drop tanks fitted, the fighter had a maximum ferry range of just over 1500 mi.

F3A-1 and F3A-1D (called Corsair Mk III by the Fleet Air Arm ):

This was the designation for Brewster-built F4U-1. Labor troubles delayed production, and the Navy ordered the company's contract terminated; they folded soon after. Poor quality wing fittings meant that these aircraft were red-lined for speed and prohibited from aerobatics after several lost their wings. None of the Brewster-built Corsairs reached front line units. 430 Brewster Corsairs (334 F3A-1 and 96 F3A-1D), more than half of Brewster's total production, were delivered to the Fleet Air Arm.

FG-1A and FG-1D (called Corsair Mk IV by the Fleet Air Arm):

This was the designation for Corsairs that were license-built by Goodyear, to the same specifications as Vought's Corsairs. The first Goodyear built FG-1 flew in February 1943 and Goodyear began delivery of FG-1 Corsairs in April 1943. The company continued production until the end of the war and delivered 4,007 FG-1 series Corsairs, including sixty FG-1Ds to the RNZAF and 857 (400 FG-1 and FG-1A, and 457 FG-1D) to the Royal Navy as Corsair Mk IVs.

F4U-1B: This was an unofficial post-war designation used to identify F4U-1s modified for Fleet Air Arm use.

F4U-1C:

The prototype F4U-1C, appeared in August 1943 and was based on an F4U-1. A total of 200 of this variant were built from July to November 1944; all were based on the F4U-1D and were built in parallel with that variant. Intended for ground-attack as well as fighter missions, the F4U-1C was similar to the F4U-1D but its six machine guns were replaced by four 20 mm AN/M2 cannons with 231 rounds of ammunition per gun. The F4U-1C was introduced to combat during 1945, most notably in the Okinawa campaign. The firepower of 20 mm was highly appreciated. It was believed that the 20 mm cannon was more effective for all types of combat work than the .50 caliber machine gun. However, despite the superior firepower, many navy pilots preferred .50 caliber machine guns in air combat due to jam and freezing problems of the 20mm cannons. These problems were reduced as the ordnance crews gained experience until the performance of the guns compared favorably with the .50 caliber, but freezing problems remained at 25,000 to 30,000 ft until gun heaters were installed.

F4U-1D (called Corsair Mk II by the Fleet Air Arm):

This variant was introduced in April 1944, and was built in parallel with the F4U-1C. It had the new R-2800-8W Double Wasp engine equipped with water injection. This change gave the aircraft up to 250 hp more power, which, in turn, increased performance. Speed was increased from 417 to 425 mph. Due to the U.S. Navy's need for fighter-bombers, it had a payload of rockets (double the -1A's) carried on permanent launching rails, as well as twin pylons for bombs or drop tanks. These modifications caused extra drag, but the additional fuel carried by the two drop tanks would still allow the aircraft to fly relatively long missions despite heavy, un-aerodynamic loads. A single piece "blown" clear-view canopy was adopted as standard equipment for the -1D model, and all later F4U production aircraft. 150 F4U-1D were delivered to the Fleet Air Arm.

F4U-1P: A rare photo reconnaissance variant.

XF4U-2: Special night fighter variant, equipped with two auxiliary fuel tanks.

F4U-2: Experimental conversion of the F4U-1 Corsair into a carrier-borne nightfighter, armed with five .50 in machine guns (the outboard, right gun was deleted), and fitted with Airborne Intercept (AI) radar set in a radome placed outboard on the starboard wing. Since Vought was preoccupied with more important projects, only 32 were converted from existing F4U-1s by the Naval Aircraft Factory and another two by front line units. The type saw combat with VF(N)-101 aboard USS Enterprise (CV-6) and USS Intrepid in early 1944, VF(N)-75 in the Solomon Islands, and VMF(N)-532 on Tarawa.

XF4U-3: Experimental aircraft built to hold different engines in order to test the Corsair's performance with a variety of power plants. This variant never entered service. Goodyear also contributed a number of airframes, designated FG-3, to the project. A single sub-variant XF4U-3B with minor modifications was also produced for the FAA.

XF4U-4: New engine and cowling.

F4U-4: The last variant to see action during World War II. Deliveries to the U.S. Navy of the F4U-4 began in early 1945. It had the 2100 hp dual-stage-supercharged -18W engine. When the cylinders were injected with the water/alcohol mixture, power was boosted to 2450 hp. The aircraft required an air scoop under the nose and the unarmored wing fuel tanks of 62 USgal capacities were removed for better maneuverability at the expense of maximum range. The propeller was changed to a four blade type. Maximum speed was increased to 448 mph and climb rate to over 4500 ft/min as opposed to the 2900 ft/min of the F4U-1A. The "4-Hog" retained the original armament and had all the external load (i.e., drop tanks, bombs) capabilities of the F4U-1D. Vought also tested the two F4U-4Xs (BuNos 49763 and 50301, prototypes for the new R2800) with fixed wingtip tanks (the Navy showed no interest) and an Aeroproducts six-blade contraprop (not accepted for production).

F4U-4B: 300 F4U-4s ordered with alternate gun armament of four 20 mm AN/M3 cannon.

F4U-4E and F4U-4N: Developed late in WWII, these nightfighters featured radar radomes projecting from the right wingtip. The -4E was fitted with the APS-4 search radar, while the -4N was fitted with the APS-6 type. In addition, these aircraft were often refitted with four 20 mm M2 cannons similar to the F4U-1C. Though these variants would not see combat during WWII, the nightfighter variants would see great use during the Korean war.

F4U-4K: Experimental radio-controlled target drone variant (1 unit built).

F4U-4P: F4U-4 equivalent to the -1P, a rare photo reconnaissance variant.

XF4U-5: New engine cowling, other extensive changes.

F4U-5: A 1945 design modification of the F4U-4, first flown on 21 December 1945, was intended to increase the F4U-4 Corsair's overall performance and incorporate many Corsair pilots' suggestions. It featured a more powerful Pratt and Whitney R-2800-32(E) engine with a two-stage supercharger, rated at a maximum of 2760 hp. Other improvements included automatic blower controls, cowl flaps, intercooler doors, and oil cooler for the engine, spring tabs for the elevators and rudder, a completely modernized cockpit, a completely retractable tail wheel, and heated cannon bays and pitot head. The cowling was lowered two degrees to help with forward visibility, but perhaps most striking as the first variant to feature all-metal wings (223 units produced). Maximum speed was 408 kn and max rate of climb at sea level 4,850 feet per minute.

F4U-5N: Radar equipped version (214 units produced)

F4U-5NL: Winterized version (72 units produced, 29 modified from F4U-5Ns (101 total)). Fitted with rubber de-icing boots on the leading edge of the wings and tail.

F4U-5P: Long-range photo-reconnaissance version (30 units produced)

F4U-6: Re-designated AU-1, this was a ground-attack version produced for the U.S. Marine Corps.

F4U-7 : AU-1 airframe with -43W engine developed for the French Navy.

FG-1E: Goodyear FG-1 with radar equipment.

FG-1K: Goodyear FG-1 as drone.

FG-3: Turbosupercharger version converted from FG-1D.

FG-4: Goodyear F4U-4, never delivered.

AU-1: U.S. Marines attack variant with extra armor to protect the pilot and fuel tank, and the oil coolers relocated inboard to reduce vulnerability to ground fire. The supercharger was simplified as the design was intended for low-altitude operation. Extra racks were also fitted. Fully loaded for combat the AU-1 weighed 20% more than a fully loaded F4U-4, and was capable of carrying 8,200 lb of bombs. The AU-1 had a maximum speed of 238 mph at 9,500 ft, when loaded with 4,600 lb of bombs and a 150 gal drop-tank. When loaded with ten HVAR rockets and two 150-gallon drop-tanks, maximum speed was 298 mph at 19,700 ft. When not carrying external loads, maximum speed was 389 mph at 14,000 ft. First produced in 1952 and used in Korea, and retired in 1957. Re-designated from F4U-6.

Super Corsair variants
In March 1944, Pratt & Whitney requested an F4U-1 Corsair from Vought Aircraft for evaluation of their new P&W R-4360, Wasp Major 4-row 28-cylinder "corncob" radial engine. The F2G-1 and F2G-2 were significantly different aircraft. F2G-1 featured a manual folding wing and 14 ft propeller, while the F2G-2 had hydraulic operated folding wings, 13 ft propeller, and carrier arresting hook for carrier use. There were five pre-production XF2G-1s: BuNo 14691, 14692, 14693 (Race 94), 14694 (Race 18), and 14695. There were ten production F2Gs: Five F2G-1s BuNo 88454 (Museum of Flight in Seattle, Washington), 88455, 88456, 88457 (Race 84), and 88458 (Race 57) and five F2G-2s BuNo 88459, 88460, 88461, 88462, and 88463 (Race 74). Five F2Gs were sold as surplus and went on to racing success after the war (indicated by the "Race" number after the BuNo), winning the Thompson trophy races in 1947 and 1949. The only surviving F2G-1s are BuNos 88454 and 88458 (Race 57). The only surviving F2G-2 was BuNo 88463 (Race 74). It was destroyed in a crash September 2012 after having a full restoration completed in July 2011.

Operators

 * Argentine Navy Naval Aviation operated 26 F4U-5/5N/5NL Corsairs from 1956 to 1968 from ARA Independencia
 * 2nd Attack Squadron
 * 2nd Attack Squadron

 * Air Force of El Salvador operated 5 F4Us and 20 FG-1Ds from 1957 to 1976
 * Fighting and Bombing Squadron
 * Fighting and Bombing Squadron

 * French Navy Aéronavale operated 69 AU-1 and 94 F4U-7 from 1954 to 1964
 * Flottille 12F
 * Flottille 14F
 * Flottille 15F
 * Flottille 17F
 * Escadrille 10S
 * Escadrille 57S
 * Escadrille 57S

 * Honduran Air Force operated 19 from 1956 to 1979
 * Honduran Air Force operated 19 from 1956 to 1979

 * Royal New Zealand Air Force operated 368 F4U-1s and 60 FG-1Ds from 1944 to 1949
 * Royal New Zealand Air Force operated 368 F4U-1s and 60 FG-1Ds from 1944 to 1949

 * No. 14 Squadron RNZAF
 * No. 15 Squadron RNZAF
 * No. 16 Squadron RNZAF
 * No. 17 Squadron RNZAF
 * No. 18 Squadron RNZAF
 * No. 19 Squadron RNZAF
 * No. 20 Squadron RNZAF
 * No. 21 Squadron RNZAF
 * No. 22 Squadron RNZAF
 * No. 23 Squadron RNZAF
 * No. 24 Squadron RNZAF
 * No. 25 Squadron RNZAF
 * No. 26 Squadron RNZAF

 * The Royal Navy's Fleet Air Arm operated 2,012 Corsairs of all types during World War II, including 95 Corsair Is (F4U-1), 510 Corsair IIs (F4U-1A), 430 Corsair IIIs (F3A-1D), and 977 Corsair IVs (FG-1D)
 * The Royal Navy's Fleet Air Arm operated 2,012 Corsairs of all types during World War II, including 95 Corsair Is (F4U-1), 510 Corsair IIs (F4U-1A), 430 Corsair IIIs (F3A-1D), and 977 Corsair IVs (FG-1D)

 * 700 Naval Air Squadron
 * 703 Naval Air Squadron
 * 706 Naval Air Squadron
 * 715 Naval Air Squadron
 * 716 Naval Air Squadron
 * 718 Naval Air Squadron
 * 719 Naval Air Squadron
 * 721 Naval Air Squadron
 * 723 Naval Air Squadron
 * 731 Naval Air Squadron
 * 732 Naval Air Squadron
 * 736 Naval Air Squadron
 * 738 Naval Air Squadron
 * 748 Naval Air Squadron
 * 757 Naval Air Squadron
 * 759 Naval Air Squadron
 * 760 Naval Air Squadron
 * 767 Naval Air Squadron
 * 768 Naval Air Squadron
 * 771 Naval Air Squadron
 * 778 Naval Air Squadron
 * 787 Naval Air Squadron
 * 791 Naval Air Squadron
 * 794 Naval Air Squadron
 * 797 Naval Air Squadron
 * 885 Naval Air Squadron
 * 1830 Naval Air Squadron
 * 1831 Naval Air Squadron
 * 1833 Naval Air Squadron
 * 1834 Naval Air Squadron
 * 1835 Naval Air Squadron
 * 1836 Naval Air Squadron
 * 1837 Naval Air Squadron
 * 1838 Naval Air Squadron
 * 1841 Naval Air Squadron
 * 1842 Naval Air Squadron
 * 1843 Naval Air Squadron
 * 1845 Naval Air Squadron
 * 1846 Naval Air Squadron
 * 1848 Naval Air Squadron
 * 1849 Naval Air Squadron
 * 1850 Naval Air Squadron
 * 1851 Naval Air Squadron
 * 1852 Naval Air Squadron

 * 🇺🇸 United States
 * United States Navy
 * United States Marine Corps

Surviving aircraft
According to the FAA there are 45 privately owned F4Us in the U.S.

title: Vought F4U Corsair