Northrop F-5

The Northrop F-5A/B Freedom Fighter and the F-5E/F Tiger II are part of a family of widely-used light supersonic fighter aircraft, designed and built by Northrop. Hundreds remain in service in air forces around the world in the early 21st century, and the type has also been the basis for a number of other aircraft.

The F-5 started life as a privately-funded light fighter program by Northrop in the 1950s. The first-generation F-5A Freedom Fighter entered service in the 1960s. During the Cold War, over 800 were produced through 1972 for U.S. allies and Switzerland. The USAF had no need for a light fighter but specifed a requirement for a supersonic trainer, procuring about 1,200 of a derivative airframe for this purpose, the Northrop T-38 Talon.

The improved second-generation F-5E Tiger II was also primarily used by American Cold War allies and, in limited quantities, served in US military aviation as a training and aggressor aircraft; Tiger II production amounted to 1,400 of all versions, with production ending in 1987. Many F-5s continuing in service into the 1990s and 2000s have undergone a wide variety of upgrade programs to keep pace with the changing combat environment.

The F-5 was also developed into a dedicated reconnaissance version, the RF-5 Tigereye. The F-5 also served as a starting point for a series of design studies which resulted in the twin-tailed Northrop YF-17 and the F/A-18 series of carrier-based fighters. The Northrop F-20 Tigershark was an advanced version of the F-5E that did not find a market. The F-5N/F variants remain in service with the United States Navy and United States Marine Corps as an adversary trainer.

Design and development

Origins

[1][2]The first Northrop YF-5A prototype aircraftIn the mid-1950s, Northrop started development on a low-cost, low-maintenance fighter, with the company designation N-156, partly to meet a US Navy requirement for a jet fighter to operate from its Escort Carriers, which were too small to operate the Navy's existing jet fighters. That requirement disappeared when the Navy decided to withdraw the Escort Carriers, but Northrop continued development of the N-156, with both a two seat advanced trainer (the N-156T), and a single-seat fighter (the N-156F) planned.

The N-156 was based on the use of a pair of an afterburning version of the General Electric J85 engine, which was originally designed to power the tiny McDonnell ADM-20 Quail decoy, which was then carried by the B-52 bomber. This requirement created a very small engine with a very high thrust-to-weight ratio. The N-156T was selected by the United States Air Force as a replacement for the T-33 in July 1965, allowing development of the trainer to progress at full speed, the first example, later designated YT-38 Talon, flying on 12 June 1959 with a total of 1,158 Talons being built by the time production ended in January 1972.

Development of the N-156F continued at a lower priority as a private venture by Northrop, which was rewarded by an order for three prototypes on 25 February 1958 as a prospective low-cost fighter that could be supplied under the Military Assistance Program for distribution to less-developed nations. The first N-156F flew at Edwards Air Force Base on 30 July 1959, exceeding the speed of sound on its first flight.

Although testing of the N-156F was successful, demonstrating unprecedented reliability and proving superior in the ground-attack role to the USAF's existing North American F-100 Super Sabres, official interest in the Northrop type waned, and by 1960 it looked as if the program was a failure. Interest revived in 1961, but when the US Army tested it, (along with the Douglas A-4 Skyhawk and Fiat G.91) for reconnaissance and close-support, although all three types proved capable during Army testing, operating fixed-wing combat aircraft was legally the responsibility of the Air Force, which would not agree to operate the N-156 or allow the Army to operate fixed-wing combat aircraft, a situation repeated with the C-7 Caribou. [3][4]VNAF F-5C Bien Hoa Air Base, 1971In 1962, however, the Kennedy Administration revived the requirement for a low-cost export fighter, selecting the N-156F as winner of the F-X competition on 23 April 1962 subsequently becoming the "F-5A", being ordered into production in October that year. It was named under the 1962 United States Tri-Service aircraft designation system, which included a re-set of the fighter number series (the General Dynamics F-111 was the highest sequentially numbered P/F-aircraft to enter service under the old number sequence).

Northrop built 636 F-5As (including the YF-5A prototype) before production ended in 1972. These were accompanied by 200 two-seat F-5B aircraft. These were operational trainers, lacking the nose-mounted cannon but otherwise combat-capable, while 86 RF-5A reconnaissance variants of the F-5A, fitted with a four-camera nose were also built. In addition, Canadair built 240 first generation F-5s under license, with CASA in Spain adding a further 70 aircraft.

F-5E and F-5F Tiger II

[5][6]Official roll-out of first USAF F-5E Tiger-IIIn 1970, Northrop won a competition for an improved International Fighter Aircraft (IFA) to replace the F-5A, with better air-to-air performance against aircraft like the Soviet MiG 21. The resultant aircraft, initially known as F-5A-21, subsequently became the F-5E. It had more powerful (5,000 lbf) General Electric J85-21 engines, and had a lengthened and enlarged fuselage, accommodating more fuel. Its wings were fitted with enlarged leading edge extensions, giving an increased wing area and improved maneuverability. The aircraft's avionics were more sophisticated, crucially including a radar (initially the Emerson Electric AN/APQ-153) (the F-5A and B had no radar). It retained the gun armament of two M39 cannon, one on either side of the nose) of the F-5A. Various specific avionics fits could be accommodated at customer request, including an inertial navigation system, TACAN and ECM equipment.

The first F-5E flew on 11 August 1972. A two-seat combat-capable trainer, the F-5F, was offered, first flying on 25 September 1974, with a new, longer nose, which, unlike the F-5B that did not mount a gun, allowed it to retain a single M39 cannon, albeit with a reduced ammunition capacity. The two-seater was equipped with the Emerson AN/APQ-157 radar, which is a derivative of the AN/APQ-153 radar, with dual control and display systems to accommodate the two-men crew, and the radar has the same range of AN/APQ-153, around 10 nmi. [7][8]Early series F-5EA reconnaissance version, the RF-5E Tigereye, with a sensor package in the nose displacing the radar and one cannon, was also offered.

The F-5E eventually received the official name Tiger II. Northrop built 792 F-5Es, 140 F-5Fs and 12 RF-5Es. More were built under license overseas: 91 F-5Es and -Fs in Switzerland, 68 by Korean Air in South Korea, and 308 in Taiwan. The F-5 proved to be a successful combat aircraft for US allies, but had little combat service with the US Air Force. The F-5E evolved into the single-engine F-5G, which was rebranded the F-20 Tigershark. It lost out on export sales to the F-16 in the 1980s.

Upgrades

The F-5E experienced numerous upgrades in its service life, with the most significant one being adopting a new planar array radar, Emerson AN/APQ-159 with a range of 20 nmi to replace the original AN/APQ-153. Similar radar upgrades were also proposed for F-5F, with the derivative of AN/APQ-159, the AN/APQ-167, to replace the AN/APQ-157, but that was cancelled. The latest radar upgrade included the Emerson AN/APG-69, which was the successor of AN/APQ-159, incorporating mapping capability. However, most nations chose not to upgrade for financial reasons, and the radar saw very little service in USAF aggressor squadrons and Swiss air force.^{[citation needed]}

Various F-5 versions remain in service with many nations. Singapore has approximately 49 modernized and re-designated F-5S (single-seat) and F-5T (two-seat) aircraft. Upgrades include new FIAR Grifo-F X-band radar from Galileo Avionica (similar in performance to the AN/APG-69), updated cockpits with multi-function displays, and compatibility with the AIM-120 AMRAAM and Rafael Python air-to-air missiles. [9][10]NASA F-5E modified for DARPA sonic boom testsOne NASA F-5E was given a modified fuselage shape for its employment in the Shaped Sonic Boom Demonstration program carried out by DARPA. It is preserved in the Valiant Air Command Warbird Museum at Titusville, Florida.

The Royal Thai Air Force (RTAF) had their F-5s undergo an entensive upgrade program, resulting in the aircraft re-designated as F-5T Tigris. They are armed with Python III and 4 missiles; and equipped with the Dash helmet-mounted cueing system.^{[citation needed]}

Similar programs have been carried out in Chile and Brazil with the help of Elbit. The Chilean upgrade, called the F-5 Tiger III Plus, incorporated a new Elta EL/M-2032 radar and other improvements. The Brazilian program, re-designated as F-5M, adds a new Grifo-F radar along with several avionics and cockpit refurbishments, including the Dash helmet. The F-5M has been equipped with new weapon systems such as the Beyond Visual Range Derby missile, Python IV short-range air-to-air missile, and several other weapons.

Operational history

[edit] United States

The first contract for the production F-5A was issued in 1962, the first overseas order coming from the Royal Norwegian Air Force on 28 February 1964. It entered service with the 4441st Combat Crew Training School of the USAF, which had the role of training pilots and ground crew for customer nations, on 30 April that year, it still not being intended that the aircraft be used in significant numbers by the USAF itself. [11][12]A F-5B of 602d TFS at Bien Hoa, 1966This changed with testing and limited deployment in 1965. Preliminary combat evaluation of the F-5A began at the Air Proving Ground Center, Eglin AFB, Florida, during the summer of 1965 under project Sparrow Hawk, with one airframe lost through pilot error on 24 June. In October 1965, the USAF began a five-month combat evaluation of the F-5A titled Skoshi Tiger. Twelve aircraft were delivered for trials to the 4503rd Tactical Fighter Squadron, and after modification with probe and drogue aerial refueling equipment, armor and improved instruments, were redesignated as the F-5C. Over the next six months, they performed combat duty in Vietnam, flying more than 2,600 sorties, both from the 3rd Tactical Fighter Wing at Bien Hoa over South Vietnam, and from Da Nang Air Base where operations were flown over Laos. One aircraft was lost in combat. Although declared a success, with the aircraft generally rated as capable a ground-attack aircraft as the F-100, but suffering from a shorter range, the program was considered a political gesture intended to aid the export of more F-5s than a serious consideration of the type for U.S. service. From April 1966 the aircraft continued operations as 10th Fighter Commando Squadron with their number boosted to 17 aircraft. (Following Skoshi Tiger the Philippine Air Force acquired 23 F-5A and B models in 1965. These aircraft, along with remanufactured Vought F-8 Crusaders, eventually replaced the Philippine Air Force's North American F-86 Sabre in the air defense and ground attack roles.) [13][14]USAF F-5F with AIM-9J Sidewinder, AGM-65 Maverick missiles and auxiliary fuel tanks over Edwards Air Force Base, 1976In June 1967, the 10th FCS's surviving aircraft were turned over to the air force of South Vietnam, which previously had only A-37 Dragonfly and A-1 Skyraider attack aircraft. This new VNAF squadron was titled the 522nd. The president of Vietnam had originally asked for F-4 Phantoms used by the Americans, but the VNAF flew primarily ground support as the communist forces employed no opposing aircraft over South Vietnam, MiG or otherwise. Ironically, when Bien Hoa was later overrun by Communist forces, several of the aircraft were captured and used operationally by the NVAF, in particular against Khmer Rouge. In view of the performance, agility and size of the F-5, it might have appeared to be a good match against the similar MiG-21 in air combat; however, US doctrine was to use heavy, faster and longer-range aircraft like the Republic F-105 Thunderchief and McDonnell Douglas F-4 Phantom II over North Vietnam. Several of the F-5s left over from the Vietnam war were sent to Poland and Russia, for advanced study of US aviation technology, while others were decommissioned and put on display at museums in Vietnam.

Although the United States does not use the F-5 in a front line role, it was adopted for an opposing forces (OPFOR) "aggressor" for dissimilar training role because of its small size and performance similarities to the Soviet MiG-21. [15][16]A former Swiss F-5N in service with US Navy aggressor squadron VFC-111The F-5E saw service with the US Air Force from 1975 until 1990, serving in the 64th Aggressor Squadron and 65th Aggressor Squadron at Nellis Air Force Base in Nevada, and with the 527th Aggressor Squadron at RAF Alconbury in the UK and the 26th Aggressor Squadron at Clark Air Force Base in the Philippines. The US Marines purchased ex-USAF models in 1989 to replace their F-21s, which served with VMFT-401 at Marine Corps Air Station Yuma. The U.S. Navy used the F-5E extensively at the Naval Fighter Weapons School (TOPGUN) when it was located at NAS Miramar, California. When TOPGUN relocated to become part of the Naval Strike and Air Warfare Center at NAS Fallon, Nevada, the command divested itself of the F-5, choosing to rely on VC-13 (redesignated VFC-13 and which already used F-5s) to employ their F-5s as adversary aircraft. Former adversary squadrons such as VF-43 at NAS Oceana, VF-45 at NAS Key West, VF-126 at NAS Miramar, and VFA-127 at NAS Lemoore have also operated the F-5 along with other aircraft types in support of Dissimilar Air Combat Training (DACT).

The U.S. Navy F-5 fleet continues to be modernized with 36 low-hour F-5E/Fs purchased from Switzerland in 2006. These were updated as F-5N/Fs with modernized avionics and other improved systems. Currently, the only U.S. Navy units flying the F-5 are VFC-13 at NAS Fallon, Nevada and VFC-111 at NAS Key West, Florida. Currently, VFC-111 operates 18 Northrop F-5N/F Tiger-IIs, of which 17 are single-seater F-5Ns and the remainder being a twin-seater F-5F, which was dubbed "FrankenTiger" and is one of only three in service with the USN, being a product of grafting the older front half fuselage of the F-5Fs into the back half fuselage of the newer low-hours F-5Es acquired from the Swiss Air Force.

According to the FAA, there are 18 privately owned F-5s in the US, including Canadair CF-5Ds.

Brazil

[17][18]Brazilian F-5 aerial refueling, 2004In October 1974, the Brazilian Air Force (FAB) ordered 36 F-5E and 6 F-5B aircraft from Northrop for $72 million. The first three aircraft arrived on 12 March 1975. In 1990, FAB retired all remaining five F-5Bs, later they were sent to Brazilian museums around the country. In 1988, FAB acquired 22 F-5E and four F-5EF second-hand USAF "agressors" fighters. 15 of these aircraft were part of the 30 units initial batch produced by Northrop.

In 2001, Elbit Systems and Embraer started work on a $230 million Brazilian F-5 modernization program, performed over an eight-year period, upgrading 46 F-5E/F aircraft, re-designated as F-5EM and F-5FM. The modernization centered on several areas: new electronic warfare systems, the Grifo F radar, an air-to-air refueling system, INS/GPS-based navigation, support for new weapons, targeting and self-defense systems, HOTAS, LCD displays, Helmet Mounted Displays (HMDs), Radar Warning Receiver, encrypted communications, cockpit compatibility for night vision goggles, On-Board Oxygen Generation System (OBOGS) and various new onboard computer upgrades. One important capability is the secure communication with R-99 airborne early warning platforms and ground stations. [19][20]FAB F-5EM cockpitExternally, the new aircraft features a larger nose cone that accommodates the larger radar equipment. The first F-5EM was handed over on 21 September 2005. In 7 July 2003, four Rafael Litening III targeting pods were ordered at a cost of USD 13 million, to be used on F-5M together with 3 Rafael Sky Shield jamming pods ordered in 5 July 2006 at a cost of USD 42 million.

In 2009, FAB bought eight single-seat and three twin-seat F-5F used aircraft from Jordan in a US$21 million deal. These aircraft were built between 1975 and 1980. On 14 April 2011, a contract of $153 million was signed with Embraer and Elbit to modernize the additional F-5s bought from Jordan, and to supply one more flight simulator as a continuation of the contract signed in 2000. These F-5s will receive the same configuration as those from the initial 46 F-5s currently completing the upgrade process. The first delivery of this second batch of upgraded jet fighters is scheduled for 2013 and they are to be withdrawn in 2030.

In the Cruzex 2006 multinational war games, a Brazilian F-5M made simulated kills on two French Dassault Mirage 2000C and one Mirage 2000N aircraft; achieved using the Derby BVR missile and information relayed from an AEW&C aircraft, the Embraer R-99. In the Cruzex 2010, two Brazilian F-5EMs made simulated kills on two French Rafale aircraft. The F-5EMs approached with their radars off, instead using the infra-red seeker on the Python IV for target acquisition.^{[citation needed]}

Ethiopia

Ethiopia received 10 F-5As and two F-5Bs from the US starting in 1966. In addition to these, Ethiopia had a training squadron equipped with at least eight Lockheed T-33 Shooting Stars. In 1970, Iran transferred at least three F-5As and Bs to Ethiopia. In 1975, another agreement was reached with the US to deliver a number of military aircraft, including 14 F-5Es and three F-5Fs; later in the same year eight F-5Es were transferred while the others were embargoed and delivered to a USAF aggressor Squadron due to the changed political situation. The US also withdrew its personnel and cut diplomatic relations. Ethiopian officers contracted a number of Israelis to maintain American equipment.

The Ethiopian F-5 fighters saw combat action against Somali forces during the Ogaden War (1977–1978). The main Somali fighter aircraft was the MiG-21MF delivered in the 1970s, supported by Mikoyan-Gurevich MiG-17s delivered in the 1960s by the Soviet Union. Ethiopian F-5E aircraft were used to gain air superiority because they could use the AIM-9B air to air missile, while the F-5As were kept for air interdiction and air strike. During this period Ethiopian F-5Es went on training against Ethiopian F-5As and F-86 Sabres (simulating Somali MiG-21s and MiG-17s).

On 17 July 1977, two Ethiopian F-5s were on combat air patrol near Harer, when four Somali MiG-21MFs were detected nearby. In the engagement, two MiG-21s were shot down while the other two had a midair collision while avoiding a AIM-9B missile. The better-trained Ethiopian Air Force F-5 pilots swiftly gained air superiority over the Somali Air Force, shooting down a number of aircraft, while other Somali aircraft were lost to air defense and to incidents. However at least three F-5s were shot down by air defense forces during attacks against supply bases in western Somalia.

Kenya

Starting on 16 October 2011 during Operation Linda Nchi, Kenyan Air Force F-5s were used to support the Kenyan forces fighting in Somalia against Al Shabab Islamists bombing targets inside Somalia and spearheading the ground forces.

Iran

[21][22]F-5E of Islamic Republic of Iran Air ForceThe Imperial Iranian Air Force received extensive US equipment in the 1960s and 1970s. Iran received its first 11 F-5A and two F-5Bs in February 1965 which were then declared operational in June 1965. Ultimately, Iran received 104 F-5A and 23 F-5Bs by 1972. From January 1974 with the first squadron of 28 F-5Fs, Iran received a total of 166 F-5E/F and 15 additional RF-5Es with deliveries ending in 1976. While receiving the F-5E and F, Iran began to sell its F-5A and B inventory to other countries, including Ethiopia, Turkey, Greece and South Vietnam; by 1976, many had been sold, except for several F-5Bs retained for training purposes.^{[citation needed]}

After the revolution, the new Islamic Republic of Iran Air Force was partially successful keeping Western fighters in service during the war with Iraq in the 1980s and the simple F-5 had a good service readiness until late in the war. Initially Iran took spare parts from foreign sources, later it was able to have its new aircraft industry keep the aircraft flying.

During the war with Iraq, IRIAF F-5s were heavily involved, flying air-to-air and air-to-ground sorties. Iranian F-5s took part in many air combats with Iraqi MiG-21, Mikoyan-Gurevich MiG-23, Mikoyan-Gurevich MiG-25, Su-20/22, Mirage F-1 and Super Etendards scoring many victories but also suffering many losses. However the exact combat record is not known with many different claims from Iraqi, Iranian and even Western and Russian sources. Adding to the haze surrounding the F-5's combat record is that many of the IRIAF's confirmed air-to-air kills were, for political reasons, attributed to the Revolutionary Guards. Nonetheless, there are reports that an F-5E, piloted by Major Yadollah Javadpour, managed to shoot down a MiG-25 on 6 August 1983. Additionally, his five claimed aerial victories, with two confirmed kills make Javadpour an ace and the world's most successful F-5 combat pilot.^{[citation needed]}

From a general standpoint, during the first years of service, Iranian F-5 fighter aircraft had the advantage in missile technology, using advanced versions of the IR seeking Sidewinder, later lost with deliveries of new missiles and fighters to Iraq.

Iran currently produces an indigenous aircraft titled, "Saegeh", which is built on the same platform as the F-5, and probably armed with Russian-made or Chinese-made munitions such as AA-10 Alamo, AA-11 Archer or C-802.^{[citation needed]}

Mexico

In 1982, Mexico received 12 F-5E/F after the purchase of 24 IAI Kfir C.1 was blocked by the U.S., because the Kfir used the American-produced J79 engine. These fighters accompanied the Lockheed T-33 and de Havilland Vampire MkIII (procured much earlier), two of the first combat jet aircraft in Mexico. The subsonic T-33 and the Vampire were introduced in the early 1960s. The F-5 gave Mexico its first supersonic platform and saw the formation of Air Squadron 401. On September 16, 1995 after more than 30 military parade flights without incidents, an F-5E collided in mid-air with three T-33s during the military parade for the Independence of Mexico. A total of 10 deaths occurred. Since then, flyovers in Mexico have been smaller in participation, for safety. In 2007, the F-5 had its 25th anniversary in Mexican Air Force service. Mexico is looking to replace its aging F-5s by 2015. It is also looking to replace its Lockheed T-33s that were retired in 2007.^{[citation needed]}

Norway

The Royal Norwegian Air Force received 108 Freedom Fighters: 16 RF-5A, 78 F-5A and 14 F-5B. The first 64 were received as military aid. They were in use by several squadrons, the first and last being 336 Squadron receiving the first aircraft in February 1966 (formal handing-over ceremony a month later), and deactivating in August 2000. Three aircraft were kept flying until 2007, serving with Kongsberg Våpenfabrikk's Eye of the Tiger-project, developing the Naval Strike Missile. The aircraft received under military aid were handed off to Greece and Turkey. Of the aircraft bought by the Norwegian Government, nine were used in exchange with US authorities for submarines of the Kobben class. Five F-5s were given to aircraft maintenance schools in October 2011. The remaining 10 are being stored at Rygge. Three survivors are exhibited at the Norwegian Armed Forces Aircraft Collection, and two at Norsk Luftfartsmuseum in Bodø.

Singapore

[23][24]A Maverick-armed F-5S Tiger-II of Republic of Singapore Air Force on static display at Paya Lebar Air Base.The F-5 earned a reputation for a jet that was hard to discern in the air and when one finally saw it, it was often after a missile or guns kill had already been called. Singapore's former Chief of Air Force, Major General Ng Chee Khern.Singapore is an important operator of the F-5E/F variant, first ordering the aircraft in 1976 during a massive expansion of the city-state's armed forces; delivery of this first batch of 18 F-5Es and three F-5Fs was completed by late February 1979, equipping the newly formed-up No. 144 Black Kite Squadron at Tengah Air Base. At the end of 1979, an order was placed for six more F-5Es, these were was delivered by 1981. In 1982, an order for three more F-5Fs was placed, these were forward delivered in September 1983 to RAF Leuchars in Scotland where they were taken over by pilots of the Republic of Singapore Air Force (RSAF). In 1983, the type took over the duties of airborne interception from the Royal Australian Air Force's Mirage IIIOs detachment stationed at Tengah.

Another order for six more F-5Es was placed in 1985, these were delivered the same year and would go on to equip the newly formed-up No. 149 Shikra Squadron at Tengah. The following year, the RSAF placed an order for its final batch of three F-5Fs and five F-5Es, these were delivered in December 1987 and July 1989, respectively. In a bid to modernize their air force, the Royal Jordanian Air Force put up seven F-5Es for sale in 1994, these were later acquired by Singapore.

From 1990 to 1991, using jigs and toolings purchased from Northrop, Singapore Aircraft Industries (SAI, now ST Aerospace) converted 8 existing F-5Es into RF-5E Tigereye variant. Subsequently, these were used to requipped No. 141 Merlin Squadron, which had traded in their older Hawker Hunter FR.74S for the newer Tigereyes in 1992 and was by then based at Paya Lebar Air Base, after the 144 Squadron had relocated there in 1986. By June 1993, all three squadrons had been relocated to the base, thus consolidating Singapore's F-5E/F operations at Paya Lebar.

In late 1991, SAI was further awarded a contract by RSAF as the main contractor to mordernise and upgrade all the F-5E/F in RSAF's inventory (including the 7 ex-Jordanian F-5Es), with Elbit Systems as sub-contractor responsible for systems integration. Included in the package was a new X band multi-mode radar (the Italian FIAR Grifo-F, with Beyond-visual-range missile and Look-down/shoot-down capabilities), a revamped cockpit with new MIL-STD-1553R databuses, GEC/Ferranti 4510 Head-up display/weapons delivery system, two BAE Systems MED-2067 Multi-function displays, Litton LN-93 inertial navigation system (similar to all those found on ST Aerospace A-4SU Super Skyhawks) and Hands On Throttle-And-Stick controls (HOTAS) to reduce pilot workload. Reportedly, the Elisra SPS2000 radar warning receiver and countermeasure system was also installed. Additionally, the starboard M-39 20mm cannon mounted in the nose was removed to make way for additional avionics (the sole cannon fitted to the two-seaters was removed because of this), and to improve maneuverability, all the upgraded aircraft were also fitted with larger leading edge root extensions (LERX). The process of rebuilding and upgrading began in March 1996 and was completed by 2001. As a result, they received the new designation of F-5S/T. In 1998, the eight RF-5Es were also upgraded, receiving the full upgrade except for the radar, these were later redesignated as RF-5S. According to a press release to the nation's newspaper, it cost approximately SGD$6 million each to upgrade the F-5S/T.

By end of 2009, the type had accumulated more than 170,000 hours of flight time in Singapore service with only two F-5Es being lost in separate accidents (in 1984 and 1991, respectively). As of June 2011, only 141 and 144 Squadron are left operating the RF-5S and F-5S/T, as 149 Squadron has since formally transitioned to the McDonnell Douglas F-15SG Strike Eagles on 5 April 2010.

Republic of China (Taiwan)

The Republic of China Air Force received its first batch of seven F-5As and two F-5Bs under the US Military Assistance Program in 1965. By 1971, the ROCAF was operating 72 F-5As and 11 F-5Bs. During 1972, the US decided to borrow 48 F-5As from Taiwan to boost the South Vietnam Air Force strength before withdrawing US forces from South Vietnam. By 1973 most of those loaned F-5As in South Vietnam were not in flying shape consequently the US decided to return 20 F-5As to Taiwan by drawing nine F-5As from US reserves while repairing a further 11 from those still in flying shape in South Vietnam. These were sent to Taiwan to make necessary repairs, with gave 28 F-5Es issued to Taiwan by May 1975 in return. By 1973, Taiwan's AIDC started local production of a first batch of 100 F-5Es in Taiwan, the first of six Peace Tiger production batches. By end of 1986 when the production line closed after completing Peace Tiger 6, the AIDC had produced 242 F-5Es and 66 F-5Fs. Adding the 28 original US-made F-5E/Fs, this made Taiwan the largest F-5E/F operator at one time, with 336 F-5E/Fs in inventory. A bit of F-20 influence can be seen in the last batch of F-5E/Fs by AIDC in Taiwan that featured the F-20's shark nose.

With the introduction of 150 F-16s, 60 Mirage 2000-5s and 130 F-CK-1s in mid-to-late-1990s, the F-5E/F series became second line fighters in ROCAF service and mostly are now withdrawn from service as squadrons converted to new fighters entering ROCAF service. Seven low airframe hours F-5Es were sent to ST Aerospace to convert them to RF-5E standard to fulfill a reconnaissance role previously undertaken by the retiring RF-104G in ROCAF service. As of 2009, only about 40 ROCAF F-5E/Fs still remain in service in training roles with about 90-100 F-5E/Fs held in reserve. The other retired F-5E/F are either scrapped, or used as decoys painted in colors representing the main front line F-16, Mirage 2000-5 or F-CK-1 fighters, and deployed around major air bases.

Taiwan also tried to upgrade the F-5E/F fleet with AIDC's Tiger 2000/2001 program. The first flight took place on 24 July 2002. The program would replace the F-5E/F's radar with F-CK-1's GD-53 radar and allow the fighter to carry a single TC-2 BVRAAM on the centerline. But lack of interest from the Taiwan/ROC Air Force eventually killed the program. The only prototype is on display in AIDC in Central Taiwan.

The only air combat actions ROCAF F-5E/F pilots saw, were not over Taiwan, but in North Yemen. In 1979, a flareup between North and South Yemen prompted the US to sell 14 F-5E/Fs to North Yemen to boost its air defense. Since no one in North Yemen knew how to fly the F-5E/F (only MiG-15s were operational at the time), US and Saudi Arabia arranged to have 80+ ROCAF F-5E pilots plus ground crew and anti-air defense units sent to North Yemen as part of North Yemen Air Force's 115th Squadron at Sana‘a operating initially just six F-5E/Fs and then from April 1979 to May 1990, added eight more. The ROCAF piloted F-5E/F scored a few kills in a few air battles, but the ground early warning radar crews and anti-air units also suffered from air attacks from South Yemen, the aircraft being piloted by Soviet crews.

Other operators

Morocco's F-5As and F-5Bs took part in the Polisario War in Western Sahara in the 1980s, fighting against the Polisario Front. Threats faced included multiple SA-6 anti-aircraft systems, a total of 14 F-5s were lost during the conflict. Starting in the 1990s, a total of 24 F-5Es have been upgraded to the F-5TIII standard.

Saudi Arabia deployed aircraft during the First Gulf War, the F-5Es flew close air support and aerial interdiction missions against Iraqi units in Kuwait. One RSAF F-5E was lost to ground fire on 13 February 1991, the pilot was killed. In Saudi service, approximately 20 Tigers have been lost due to various causes.^{[citation needed]}

The Philippine Air Force received 30 F-5A/B in 1966. The F-5A/Bs were used by the Blue Diamonds Aerobatic team.^{[citation needed]} In 2011, the Philippines decommissioned their remaining F-5A/B fleet, including those transferred from Taiwan and South Korea, The Philippine Air Force planned to order six new fighters in July 2011. reportedly F-16s will be ordered as a replacement.

Specifications (F-5E Tiger II)

[25]General characteristics

• Crew: 1
• Length: 47 ft 4¾ in (14.45 m)
• Wingspan: 26 ft 8 in (8.13 m)
• Height: 13 ft 4½ in (4.08 m)
• Wing area: 186 ft² (17.28 m²)
• Airfoil: NACA 65A004.8 root, NACA 64A004.8 tip
• Empty weight: 9,558 lb (4,349 kg)
• Loaded weight: 15,745 lb (7,157 kg)
• Max. takeoff weight: 24,722 lb (11,214 kg)
• Powerplant: 2 × General Electric J85-GE-21B turbojet
  • Dry thrust: 3,500 lbf (15.5 kN) each
  • Thrust with afterburner: 5,000 lbf (22.2 kN) each
• Zero-lift drag coefficient: 0.0200
• Drag area: 3.4 ft² (0.32 m²)
• Aspect ratio: 3.86
• Internal fuel: 677 US gal (2,563 L)
• External fuel: 275 US gal (1,040 L) per tank in up to 3 tanks

Performance

• Maximum speed: 917 kn (1,060 mph, 1,700 km/h, Mach 1.6)
• Range: 760 nmi (870 mi, 1,405 km)
• Ferry range: 2,010 nmi (2,310 mi, 3,700 km)
• Service ceiling: 51,800 ft (15,800 m)
• Rate of climb: 34,400 ft/min (175 m/s)
• Lift-to-drag ratio: 10.0

Armament

• Guns: 2× 20 mm (0.787 in) M39A2 Revolver cannons in the nose, 280 rounds/gun
• Hardpoints: 7 total (3× wet): 2× wing-tip AAM launch rails, 4× under-wing & 1× under-fuselage pylon stations with a capacity of 7,000 pounds (3,200 kg) and provisions to carry combinations of:
  • Rockets:
    • 2× LAU-61/LAU-68 rocket pods (each with 19× /7× Hydra 70 mm rockets, respectively); or
    • 2× LAU-5003 rocket pods (each with 19× CRV7 70 mm rockets); or
    • 2× LAU-10 rocket pods (each with 4× Zuni 127 mm rockets); or
    • 2× Matra rocket pods (each with 18× SNEB 68 mm rockets)
  • Missiles:
    • 4× AIM-9 Sidewinders or 4× AIM-120 AMRAAM air-to-air missile
    • 2× AGM-65 Maverick air-to-surface missiles
  • Bombs: A variety of air-to-ground ordnance such as the Mark 80 series of unguided bombs (including 3 kg and 14 kg practice bombs), CBU-24/49/52/58 cluster bomb munitions, napalm bomb canisters and M129 Leaflet bomb, and laser guided bombs of Paveway family.
• Others: up to 3× 150/275 US gallon Sargent Fletcher drop tanks for ferry flight or extended range/loitering time.

Avionics

• Emerson Electric AN/APQ-153 radar on early batch of F-5E
• Emerson Electric AN/APQ-159 radar on later production F-5E
• AN/AVQ-27 Laser Target Designator Set (LTDS), for F-5B and F-5F only.