Editing Northrop F-5 (section)

==Design and development==

===Origins===
The design effort was led by Northrop vice president of engineering and aircraft designer [[Edgar Schmued]],<ref>{{harvnb|Garrison|2005}}</ref> who previously at [[North American Aviation]] had been the chief designer of the successful [[North American P-51 Mustang]] and [[North American F-86 Sabre|F-86 Sabre]] fighters. Schmued recruited a strong engineering team to Northrop.<ref>{{harvnb|Wagner|2000|p=195}}.</ref>

In December 1953, [[NATO]] issued [[NBMR-1]], calling for a lightweight tactical fighter capable of carrying conventional and nuclear weapons and operating from rough airfields. In late 1954, a Northrop team toured Europe and Asia to examine both the NBMR-1 and the needs of [[SEATO]] members. From this tour, Schmued gave his team the goal of reversing the trend in fighter development towards greater size and weight in order to deliver an aircraft with high performance, enhanced maneuverability, and high reliability, while still delivering a cost advantage over contemporary fighters.<ref>{{harvnb|Stuart|1978|pp=5–7}}.</ref><ref>{{Cite web |last= |date=1987-01-16 |title=Era of the F-5 Ends After Three Decades |url=https://www.latimes.com/archives/la-xpm-1987-01-16-fi-3612-story.html |access-date=2024-01-25 |website=Los Angeles Times |language=en-US}}</ref> Recognizing that expensive jet aircraft could not viably be replaced every few years, he also demanded "engineered growth potential" allowing service longevity in excess of 10 years.<ref>{{harvnb|Wagner|2000|p=197}}.</ref>

The design began to firm up in 1955 with the introduction of the [[General Electric J85]] turbojet engine. Originally developed for McDonnell's [[ADM-20 Quail]] decoy for use on the [[Boeing B-52 Stratofortress]],<ref name="Claws p111-4">{{harvnb|Braybrook|1982|pp=111–114}}.</ref> the J85 had a [[thrust-to-weight ratio]] of 6.25 to 7.5 depending on the version, giving it a notable advantage over contemporaries such as the 4.7 ratio of the [[J79]] engine used in the [[McDonnell Douglas F-4 Phantom II|F-4 Phantom]].<ref>{{harvnb|Stuart|1978|p=21}}.</ref>

===Design evolution===
Using a pair of J85s as the baseline, the team began considering a series of prospective designs. Among the earliest concepts was the N-156TX of March 1955. This mounted the engines in pods, one under each wing about mid-span. The fuselage was quite slim compared to the final design, with a crew of two under a narrow cockpit canopy.<ref name=f1960>''Flight'', 8 January 1960, pp. 46-47</ref>

That year, the [[US Navy]] expressed an interest in a fighter to operate from its [[escort carrier]]s, which were too small to operate the Navy's existing jet fighters. Northrop responded with a radical redesign, PD-2706, which placed the engines against the fuselage in short ducts exiting in front of the tail area, like the F-4, and moved the elevator up to form a [[T-tail]]. The resulting design had a much shorter fuselage and was quite compact.<ref name=f1960/> Development along these lines ended when the Navy decided to withdraw the escort carriers. Northrop continued development of the N-156, both as a two-seat advanced trainer, designated as N-156T, and a single-seat fighter, designated as N-156F.<ref>{{harvnb|Paloque|2013|pp=4–7}}.</ref>

[[File:Northrop YF-5A.jpg|thumb|The first Northrop YF-5A prototype]]
Another highly influential figure was chief engineer Welko Gasich,<ref>{{harvnb|Garrison|2005}}.</ref> who convinced Schmued that the engines must be located within the fuselage for maximum performance.<ref name="s7">{{harvnb|Stuart|1978|p=7}}.</ref> This led to the January 1956 PD-2812 version which began to look a lot like the final product, although this version had a long-span low-mounted elevator with notable anhedral. March 1956's PD-2832 moved to a more conventional elevator and had a strongly swept vertical stabilizer. The design underwent several further versions over the next year which experimented with different nose designs and continued to lengthen the fuselage. The final design, PD-2879D, emerged in December 1956.<ref name=f1960/>

Gasich also introduced the concept of "life cycle cost" into fighter design, which provided the foundation for the F-5's low operating cost and long service life. A Northrop design study stated "The application of advanced technology was used to provide maximum force effectiveness at minimum cost.  This became the Northrop philosophy in the development of the T-38 and F-5 lightweight trainer and fighter aircraft."<ref name="s7"/>

===Into production===
{{Blockquote |quote=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 [by F-5] had already been called. |source=<small>—Singapore's former Chief of Air Force and F-5 pilot, Major General [[Ng Chee Khern]].<ref name="AFM275"/></small>}}

The N-156T was quickly selected by the [[United States Air Force]] as a replacement for the [[Lockheed T-33 Shooting Star|T-33]] in July 1956. On 12 June 1959, the first prototype aircraft, which was subsequently designated as [[Northrop T-38 Talon|YT-38 Talon]], performed its first flight. By the time production had ended in January 1972, a total of 1,189 Talons had been produced.<ref name="WAPJ 25 p50-1">Lake and Hewson 1996, pp. 50–51.</ref><ref name="Claws p114">{{harvnb|Braybrook|1982|p=114}}</ref> Development of the N-156F continued at a lower priority as a private venture by Northrop; on 25 February 1958, an order for three prototypes was issued for 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 [[Supersonic#Supersonic flight|speed of sound]] on its first flight.<ref name="WAPJ 25 p51">{{harvnb|Lake|Hewson|1996|p=51}}</ref>

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 Sabre]]s, official interest in the Northrop type waned, and by 1960 it looked as if the program was a failure. Interest revived in 1961 when the [[United States 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 allow the Army to operate fixed-wing combat aircraft, a situation repeated with the [[de Havilland Canada DHC-4 Caribou|C-7 Caribou]].<ref name="Harding army">{{harvnb|Harding|1990|pp=118–119, 122–123, 188–189}}.</ref>

In 1962, 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", and was ordered into production in October that year.<ref name="WAPJ 25 p52-3">{{harvnb|Lake|Hewson|1996|pp=52–53}}</ref> It was named under the [[1962 United States Tri-Service aircraft designation system]], which included a re-set of the fighter number series. Northrop manufactured a total of 624 F-5As, including three YF-5A prototypes,<ref name="nat_museum_F-5">{{cite web |title= Northrop YF-5A Freedom Fighter |website= National Museum of the US Air Force |publisher= US Air Force |url= https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196074/northrop-yf-5a-freedom-fighter/ |archive-url= https://web.archive.org/web/20230113193331/https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196074/northrop-yf-5a-freedom-fighter/ |archive-date= 13 January 2023 |url-status= live |access-date= 28 February 2023}}</ref> before production ended in 1972. A further 200 F-5B two-seat trainer aircraft, lacking nose-mounted cannons but otherwise combat-capable, and 86 RF-5A reconnaissance aircraft, fitted with four-camera noses, were also built. In addition, [[Canadair]] built 240 first generation F-5s under license, [[Construcciones Aeronáuticas SA|CASA]] in Spain built 70 more aircraft.<ref name="WAPJ 25 p82-3">{{harvnb|Lake|Hewson|1996|pp=82–83}}</ref>

The [[Royal Norwegian Air Force]] placed the first international order on 28 February 1964.<ref>{{Cite web |last= |date=1987-01-16 |title=Era of the F-5 Ends After Three Decades |url=https://www.latimes.com/archives/la-xpm-1987-01-16-fi-3612-story.html |access-date=2025-02-08 |website=Los Angeles Times |language=en-US}}</ref><ref>{{Cite web |title=Northrop F-5A Freedom Fighter |url=https://www.joebaugher.com/usaf_fighters/f5_2.html |access-date=2025-02-08 |website=www.joebaugher.com}}</ref>

===F-5E and F-5F Tiger II===
[[File:Northrop F-5E (Tail No. 11417) 061006-F-1234S-067.jpg|thumb|Official roll-out of first USAF F-5E Tiger II]]
[[File:F5E Tiger II B83 HAFB.jpg|thumb|F-5E Tiger II with [[B83 nuclear bomb]] at [[Hill Aerospace Museum]]]]

In 1970, Northrop won the International Fighter Aircraft (IFA) competition to replace the F-5A, with better air-to-air performance against aircraft like the Soviet [[Mikoyan-Gurevich MiG-21|MiG-21]]. The resulting aircraft, initially known as F-5A-21, subsequently became the F-5E. It had two more powerful GE J85-21 engines, each with {{convert|3600|lbf|kN|abbr=on}} dry thrust and {{convert|5000|lbf|kN|abbr=on}} in afterburner, and had a lengthened and enlarged fuselage to accommodate more fuel. Its wings were fitted with enlarged [[leading edge extension]]s, 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]]) (F-5A and B had no radar). It retained the gun armament of two [[M39 cannon]]s, one on either side of the nose of the F-5A. Various specific avionics fits could be accommodated at a customer's request, including an [[inertial navigation system]], [[TACAN]] and [[Electronic countermeasure|ECM]] equipment.<ref name="WAPJ 25 p58-9 70-1">{{harvnb|Lake|Hewson|1996|pp=58–59, 70–71}}</ref> Additionally the two position nose landing gear from the Canadian CF-5 was incorporated to reduce takeoff distance.<ref name="Claws p116"/>

The first F-5E flew on 11 August 1972.<ref name="Claws p116">{{harvnb|Braybrook|1982|p=116}}.</ref> A two-seat combat-capable trainer, the F-5F, was offered, first flying on 25 September 1974, at Edwards Air Force Base, with a new nose, that was three feet longer, 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.{{sfn|Lake|Hewson|1996|pp=71–72}} 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 [[nautical mile|nmi]]. On 6 April 1973, the 425th TFS at Williams Air Force Base, Arizona, received the first F-5E Tiger II.<ref>{{Cite book |last=Tambini |first=Anthony J. |url=https://books.google.com/books?id=JvANc4CpPnwC&dq=F-5E+Tiger+II+%221973%22+%22Williams+Air+Force+Base%22&pg=PA55 |title=F-5 Tigers Over Vietnam |date=2001 |publisher=Branden Books |isbn=978-0-8283-2059-7 |language=en}}</ref>

[[File:Northrop F-5E (Tail No. 11419) (cropped).jpg|thumb|left|An early series F-5E]]
A [[aerial reconnaissance|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; 792 F-5Es, 146 F-5Fs and 12 RF-5Es were eventually built by Northrop.<ref name="WAPJ 25 p82-3"/> More were built under license overseas: 91 F-5Es and F-5Fs in Switzerland,<ref name="WAPJ 25 p103">{{harvnb|Lake|Hewson|1996|p=103}}</ref> 68 by [[Korean Air]] in South Korea,<ref name="WAPJ 25 p96">{{harvnb|Lake|Hewson|1996|p=96}}</ref> and 308 in [[Taiwan]].<ref name="WAPJ 25 p104">{{harvnb|Lake|Hewson|1996|p=104}}</ref>

The F-5E proved to be a successful combat aircraft in service with US allies, but had no combat service with the US Air Force, though the F-5A with modifications, designated F-5C, was flown by the US in Vietnam.<ref>Tambini, Anthony, ''F-5 Tigers over Vietnam'', 2014, {{ISBN|9780828320597}}.</ref> The F-5E evolved into the single-engine F-5G, which was rebranded the [[Northrop F-20 Tigershark|F-20 Tigershark]]. It lost out on export sales to the [[F-16 Fighting Falcon]] 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&nbsp;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.<ref>{{cite web|title=F-5 Tiger II|url=http://www.touchdown-aviation.com/types/swiss-air-force/f-5-tiger-ii.php|website=Touchdown Aviation|access-date=29 January 2016|archive-url=https://web.archive.org/web/20160907134423/http://www.touchdown-aviation.com/types/swiss-air-force/f-5-tiger-ii.php|archive-date=7 September 2016|url-status=dead|df=dmy-all}}</ref>

Various F-5 versions remain in service with many nations. Having taken delivery of its first F-5 Tigers in 1979, [[Singapore]] operated approximately 49 modernized and re-designated F-5S (single-seat) and F-5T (two-seat) aircraft until the early 2010s when they were retired from service.<ref>{{Cite web|last=Waldron2018-02-04T04:02:00+00:00|first=Greg|title=SINGAPORE: RSAF chief discusses future capabilities|url=https://www.flightglobal.com/helicopters/singapore-rsaf-chief-discusses-future-capabilities/126941.article|access-date=2020-12-04|website=[[FlightGlobal]]|language=en}}</ref> Upgrades included 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 Advanced Defense Systems|Rafael]] [[Python (missile)|Python]] [[air-to-air missile]]s.<ref name="AFM275">Yeo, Mike. "Tigers over Lion City." ''[[AirForces Monthly]]'' ([[Key Publishing]]), Issue 275, March 2011, pp. 86–91. {{ISSN|0955-7091}}. Retrieved: 8 June 2011.</ref><ref name="FSRSAF">[http://www.mindef.gov.sg/imindef/mindef_websites/atozlistings/air_force/assets/aircraft/fighters.html "Press release: Assets: Fighter aircraft."] {{Webarchive|url=https://web.archive.org/web/20140202125847/http://www.mindef.gov.sg/imindef/mindef_websites/atozlistings/air_force/assets/aircraft/fighters.html |date=2 February 2014}} ''Ministry of Defence (Singapore)'', 24 April 2010. Retrieved: 8 June 2011.</ref><ref name="FGBRF5">[http://www.flightglobal.com/articles/2000/04/11/64402/brazil-favours-grifo-f-radar-for-f-5br-upgrade.html "Brazil favours Grifo F radar for F-5BR upgrade".] ''[[FlightGlobal]]'', 11 April 2000. Retrieved: 8 June 2011.</ref>

[[File:Northrop F-5E (modified) DARPA sonic tests 04.07R.jpg|thumb|NASA F-5E modified for DARPA sonic boom tests]]
One [[National Aeronautics and Space Administration]] (NASA) F-5E was given a modified fuselage shape for its employment in the [[Shaped Sonic Boom Demonstration]] program carried out by [[Defense Advanced Research Projects Agency]] (DARPA). It is preserved in the [[Valiant Air Command Warbird Museum]] at [[Titusville, Florida]].<ref>[http://www.vacwarbirds.org/AirplaneGallery/index.html "F5E-Modified."] {{webarchive|url=https://web.archive.org/web/20120212002603/http://www.vacwarbirds.org/AirplaneGallery/index.html |date=12 February 2012}} ''vacwarbirds.org.'' Retrieved: 24 April 2012.</ref>

The [[Royal Thai Air Force]] (RTAF) had their F-5s undergo an extensive upgrade program, resulting in the aircraft re-designated as F-5T Tigris. They are armed with Python III and IV missiles; and equipped with the Dash helmet-mounted cueing system.<ref>{{Cite web|url=https://www.ainonline.com/aviation-news/defense/2017-08-10/thailands-latest-f-5-upgrade-features-israeli-kit|title=Thailand's Latest F-5 Upgrade Features Israeli Kit|first=Chen|last=Chuanren|website=Aviation International News}}</ref>

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 radar|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 missile|Beyond Visual Range]] [[Derby (missile)#Derby|Derby]] missile, [[Python IV#Python-4|Python IV]] short-range air-to-air missile, [[SMKB]] "smart" bombs,<ref>"Bombas Guiada SMKB." ''Revista Asas''(Portuguese), Volume 61'', June 2011, p. 29. {{ISSN|1413-1218}}.''</ref> and several other weapons.<ref>[http://www.flightglobal.com/news/articles/denels-a-darter-makes-test-debut-323063/ "Denel's A-Darter makes test debut"] {{Webarchive|url=https://web.archive.org/web/20130521111653/http://www.flightglobal.com/news/articles/denels-a-darter-makes-test-debut-323063/ |date=21 May 2013}} ''Flight Global'', 26 February 2009. Retrieved: 28 January 2012.</ref><ref>[http://www.alide.com.br/noticias/fab39/index.htm "FAB comemora dia da Aviação de Caça!" (in Portuguese).] {{Webarchive|url=https://web.archive.org/web/20080919144151/http://www.alide.com.br/noticias/fab39/index.htm |date=19 September 2008}} ''alide.com.br.'' Retrieved: 28 January 2012.</ref><ref>[http://www.aereo.jor.br/2010/11/04/f-5em-com-missil-python-iv/ "F-5EM com míssil Python IV" (in Portuguese).] {{Webarchive|url=https://web.archive.org/web/20111225095509/http://www.aereo.jor.br/2010/11/04/f-5em-com-missil-python-iv/ |date=25 December 2011}} ''Poder Aéreo'', 4 November 2010. Retrieved: 28 January 2012.</ref><ref>[http://www.aereo.jor.br/2008/08/24/as-garras-afiadas-do-f-5em/ "As garras afiadas do F-5EM" (in Porguguse).] {{Webarchive|url=https://web.archive.org/web/20120216215335/http://www.aereo.jor.br/2008/08/24/as-garras-afiadas-do-f-5em/ |date=16 February 2012}} ''Poder Aéreo'', 24 August 2008. Retrieved: 28 January 2012.</ref>