Editing Mikoyan-Gurevich MiG-21 (section)

==Development==

===Origins===
The MiG-21 jet fighter was a continuation of Soviet jet fighters, starting with the subsonic [[Mikoyan-Gurevich MiG-15|MiG-15]] and [[Mikoyan-Gurevich MiG-17|MiG-17]], and the supersonic [[Mikoyan-Gurevich MiG-19|MiG-19]]. A number of experimental [[Mach number|Mach]] 2 Soviet designs were based on nose intakes with either [[Swept wing|swept-back wings]], such as the [[Sukhoi Su-7]], or tailed [[delta wing|deltas]], of which the MiG-21 would be the most successful.

Development of what would become the MiG-21 began in the early 1950s when [[Mikoyan]] OKB finished a preliminary design study for a [[prototype]] designated Ye-1 in 1954. This project was very quickly reworked when it was determined that the planned engine was underpowered; the redesign led to the second prototype, the Ye-2. Both these and other early prototypes featured swept wings. The first prototype with the [[delta wings]] found on production variants was the Ye-4. It made its maiden flight on 16 June 1955 and its first public appearance during the [[Soviet Aviation Day|Soviet Aviation Day display]] at Moscow's [[Tushino airfield]] in July 1956.

In the West, due to the lack of available information, early details of the MiG-21 often were confused with those of similar Soviet fighters of the era. In one instance, ''Jane's All the World's Aircraft 1960–1961'' listed the "Fishbed" as a [[Sukhoi Design Bureau|Sukhoi design]] and used an illustration of the [[Sukhoi Su-9|Su-9 'Fishpot']].

===Design===
[[File:MiG-21 on display on top of Verkkokauppa in Helsinki.jpg|thumb|Retired Finnish MiG-21bis on top of Verkkokauppa store in Helsinki (Tyynenmerenkatu 11).]]
[[File:MiG-21 BIS on display in Helsinki.jpg|thumb|MiG-21bis rear.]]
[[File:Close up of the landing gear bay (MiG-21 BIS).jpg|thumb|Close-up of the landing gear bay.]]
[[File:MiG-21M Preschen (22951457305).jpg|thumb|MiG-21М National People's Army of the GDR, August 1990]]

The MiG-21 was the first successful Soviet aircraft combining [[fighter aircraft|fighter]] and [[interceptor aircraft|interceptor]] characteristics in a single aircraft. It was a lightweight fighter, achieving Mach 2 with a relatively low-powered [[afterburner (engine)|afterburning]] [[turbojet]], and is thus comparable to the American [[Lockheed F-104 Starfighter]] and [[Northrop F-5|Northrop F-5 Freedom Fighter]] and the French [[Dassault Mirage III]].<ref name="Gordon 2008" /> Its basic layout was used for numerous other Soviet designs; delta-winged aircraft included the [[Sukhoi Su-9|Su-9]] interceptor and fast [[Mikoyan-Gurevich Ye-150 family|Ye-150]] prototype from the MiG bureau, while the successful mass-produced frontline fighter [[Sukhoi Su-7|Su-7]] and Mikoyan's [[Mikoyan-Gurevich I-75|I-75]] experimental interceptor combined a similar fuselage shape with swept-back wings. However, the characteristic layout with the [[inlet cone|shock cone]] and front air intake did not see widespread use outside the USSR and ultimately proved to have limited development potential, mainly due to the small available space for the radar.

Like many aircraft designed as interceptors, the MiG-21 had a short range. This was exacerbated by the poor placement of the internal fuel tanks ahead of the centre of gravity. As the internal fuel was consumed, the center of gravity would shift rearward beyond acceptable parameters. This had the effect of making the plane [[Longitudinal static stability|statically unstable]] to the point of being difficult to control, resulting in an endurance of only 45 minutes in clean condition. This can be somewhat countered by carrying fuel in external tanks closer to the center of gravity. The Chinese variants somewhat improved the internal fuel tank layout (as did the second generation of Soviet variants), and also carried significantly larger external fuel tanks to counter this issue.<ref>Civil Airworthiness Certification: Former Military High-Performance Aircraft, United States Department of Transportation, Federal Aviation Administration.</ref> Additionally, when more than half the fuel was used up, violent maneuvers prevented fuel from flowing into the engine,<ref>{{Cite web |title=ODIN - OE Data Integration Network |url=https://odin.tradoc.army.mil/WEG/Asset/6e76cf95da7f7ee76e8f4b3d643c027e |access-date=2025-01-06 |website=odin.tradoc.army.mil}}</ref> thereby causing it to shut down in flight. This increased the risk of tank implosions (MiG-21 had tanks pressurized with air from the engine's compressor), a problem inherited from the [[Mikoyan-Gurevich MiG-15|MiG-15]], [[Mikoyan-Gurevich MiG-17|MiG-17]] and [[Mikoyan-Gurevich MiG-19|MiG-19]].<ref name="J F Dunnigan">Dunnigan, James F. ''How to Make War, A Comprehensive Guide to Modern Warfare in the 21st Century, Fourth Edition.'' Harper Collins Publishers Inc. 2003. {{ISBN|978-0060090128}}</ref> The short endurance and low fuel capacity of the MiG-21F, PF, PFM, S/SM and M/MF variants—though each had a somewhat greater fuel capacity than its predecessor—led to the development of the MT and SMT variants. These had an increased range of {{convert|250|km|0|abbr=on}} compared to the MiG-21SM, but at the cost of worsening all other performance figures, such as a lower service ceiling and slower time to altitude.<ref name="Gordon 2008" />

The delta wing, while excellent for a fast-climbing interceptor, meant any form of turning combat led to a rapid loss of speed. However, the light loading of the aircraft could mean that a [[climb rate]] of 235&nbsp;m/s (46,250&nbsp;ft/min) was possible with a combat-loaded MiG-21bis,<ref name="Gordon 2008" /> not far short of the performance of the later [[General Dynamics F-16 Fighting Falcon|F-16A]]. MiG-21's [[Tumansky R-25]] jet engine's specialty was the addition of a second fuel pump in the afterburning stage. Activating the ЧР (rus. "чрезвычайный режим" - emergency mode)(Emergency Power Rating, EPR in India) booster feature allows the engine to develop 97.4 kilonewtons (21,896&nbsp;lbf) of thrust under 2,000 meters (6,600&nbsp;ft) of altitude. The rpm of the engine would increase by 2.5% and the compression ratio would thus increase, with a rise in exhaust temperature. The limit of operation is 2 minutes for both practice and actual wartime use, as further use causes the engine to overheat. The fuel consumption increased by 50% over the rate in full afterburner. Use of this temporary power gave the MiG-21bis slightly better than 1:1 thrust-to-weight ratio and a climbing rate of 254 meters/second, equalling the F-16's nominal capabilities in a close-quarters dogfight.
The use of [[War emergency power|WEP]] thrust was limited to 2 minutes to reduce stress on the engines' 750 (250+250+250) flight hours lifetime since every second of super-afterburner counted as several minutes of regular power run due to extreme thermal stress. With WEP on, the MiG-21bis's R-25 engine produced a huge 10–12 meter long blowtorch exhaust, with six or seven brightly glowing rhomboid "shock diamonds" visible inside the exhaust. The Russians gave the emergency power setting its "diamond regime" name, never used in India.<ref>{{cite web | url=https://forums.eagle.ru/showthread.php?t=125066 |title = Afterburner/Engine simulation question - ED Forums| date=28 May 2014 }}</ref> Given a skilled pilot and capable missiles, it could give a good account of itself against contemporary fighters. Its G-limits were increased from +7Gs in initial variants to +8.5Gs in the latest variants.<ref name=MiG-21BIS>Král, Martin. {{usurped|1=[https://web.archive.org/web/20170702092826/http://www.soviethammer.info/blog/799377-mig-21bis "MiG-21BIS."]}} ''Soviet Hammer,'' 6 April 2012. Retrieved: 28 June 2012.</ref> It was replaced by the newer variable-geometry [[Mikoyan-Gurevich MiG-23|MiG-23]] and [[Mikoyan MiG-27|MiG-27]] for ground support duties. However, not until the [[Mikoyan-Gurevich MiG-29|MiG-29]] would the Soviet Union ultimately replace the MiG-21 as a maneuvering dogfighter to counter new American air superiority types.

The MiG-21 was exported widely and remains in use. The aircraft's simple controls, engine, weapons, and avionics were typical of Soviet-era military designs. The use of a tail with the delta wing aids stability and control at the extremes of the [[flight envelope]], enhancing safety for lower-skilled pilots; this, in turn, enhanced its marketability in exports to developing countries with limited training programs and restricted pilot pools. While technologically inferior to the more advanced fighters it often faced, low production and maintenance costs made it a favorite of nations buying [[Eastern Bloc]] military hardware. Several Russian, Israeli and Romanian firms have begun to offer upgrade packages to MiG-21 operators, designed to bring the aircraft up to a modern standard, with greatly upgraded avionics and armaments.<ref name="Gordon 2008" />

===Production===
[[File:MiG-21F-13 Fishbed C.JPG|thumb|Czechoslovak MiG-21F-13 "Fishbed C"]]
A total of 10,645 aircraft were built in the USSR. They were produced in three factories: AZ 30{{refn|"AZ" – abbreviation for Russian "Авиационный Завод" – АЗ (Aviation Plant).|group=N}} (3,203 aircraft) in Moscow (also known as ''MMZ Znamya Truda''), GAZ 21 (5,765 aircraft) in [[Gorky (city)|Gorky]],{{refn|Now called [[Nizhny Novgorod]].|group=N}} and TAZ 31 (1,678 aircraft) in [[Tbilisi]]. Generally, Gorky built single-seaters for the Soviet forces. Moscow constructed single-seaters for export, and Tbilisi manufactured two-seaters both for export and the USSR, though there were exceptions. The MiG-21R and MiG-21bis for export and for the USSR were built in Gorky, 17 single-seaters were built in Tbilisi (MiG-21 and MiG-21F), the MiG-21MF was first constructed in Moscow and then Gorky, and the MiG-21U was built in Moscow as well as in Tbilisi.<ref name="Gordon 2008" />

{|class="wikitable"
|-
!Gorky
|83 MiG-21F; 513 MiG-21F-13; 525 MiG-21PF; 233 MiG-21PFL; 944 MiG-21PFS/PFM; 448 MiG-21R; 145 MiG-21S/SN; 349 MiG-21SM; 281 MiG-21SMT; 2013 MiG-21bis; 231 MiG-21MF
|-
!Moscow
|MiG-21U (all export units); MiG-21PF (all export units); MiG-21FL (all units not built by HAL); MiG-21M (all); 15 MiG-21MT (all)
|-
!Tbilisi
|17 MiG-21 and MiG-21F; 181 MiG-21U ''izdeliye'' 66–400 and 66–600 (1962–1966); 347 MiG-21US (1966–1970); 1133 MiG-21UM (1971 to end)
|}

A total of 194 MiG-21F-13s were built under licence in [[Czechoslovakia]], and [[Hindustan Aeronautics Ltd.]] of India built 657 MiG-21FL, MiG-21M and MiG-21bis (of which 225 were bis)

===Cost===
Due to the mass production, the aircraft was very cheap: the MiG-21MF, for example, was cheaper than the [[BMP-1]].<ref>{{cite web|url=http://www.airwar.ru/enc/fighter/j7.html|title=Chengdu J-7 (J-7I)|website=www.airwar.ru|access-date=2 February 2019}}</ref> The [[F-4 Phantom]]'s cost was several times higher than MiG-21.{{citation needed|date=May 2020}}