List of Mikoyan-Gurevich MiG-21 variants
This is a list of variants and specifications for variants of the Mikoyan-Gurevich MiG-21, which differed considerably between models. Variants. All information in this section adapted from "MiG-21" (2008). Chinese-built variants of the MiG-21 are designated Chengdu J-7 and F-7 (for export). Only the initial version of the J-7 was a copy of a MiG-21 variant, namely the MiG-21F-13. Though an agreement had been reached between China and the USSR for licence production of the MiG-21 in China, political relations soured between the two countries, causing Soviet assistance to stop. The Chinese  reverse-engineered parts of the handful of MiG-21F-13s supplied from the USSR, in order to make up for blueprints and documentation that had not yet been shipped over from the USSR at the time of the political rift. All subsequent development of the J-7 was indigenous to China and different from Soviet-made versions. The Guizhou JL-9 trainer, first flown in 2003, is also based on the MiG-21 airframe. Between 1962 and 1972 the MiG-21F-13 version was manufactured under license by Aero Vodochody, in Czechoslovakia under the name of Aero S-106 . Aero Vodochody (then Středočeské strojírny, n.p.), built a total  of 194 planes during this period, under the cover designation article Z-159. It followed the MiG-15 and MiG-19S built in Vodochody factory from the fifties to sixties. The sole locally built version of the MiG-21F-13 differed externally from the Soviet-built examples by the solid dural sheet fairing behind the cockpit canopy, as opposed to the transparent one on the original Soviet MiGs. These machines were built for the Czechoslovak Air Force and also for export. The R13-300 engines were imported from the Soviet Union. The production of the MiG-21s in India under license by Hindustan Aeronautics in Nasik  started with the MiG-21FL in 1966 in four phases starting with the assembly of CKD kits, moving on to subassemblies, parts, and finally advancing to production from scratch. 205 MiG-21FLs, designated Type 77 and nicknamed "Trishul" ("Trident), were built in India between 1966 and 1972; the first one built entirely from Indian-made components was delivered to the IAF on 19 October 1970, with the first Indian-made R11F2S-300 powerplant leaving the assembly line on 2 January 1969. In 1971 HAL production was switched to an improved version of the MiG-21M ("izdeliye" 96), which was designated Type 88 by  HAL; as this variant was produced exclusively in India, no izdeliye designation is applicable. The first Type 88 MiG-21M was delivered to the IAF on 14 February 1973 and the last on 12 November 1981, with a total of 158 built. The last variant to be produced by HAL was the MiG-21bis. A total of 75 were built in 1977 from CKD kits, and a further 220 were built from scratch by 1984. Despite a series of crashes during the 1990s, the Indian Air Force has decided to upgrade about 125 of the MiG-21bis in its inventory to the  MiG-21UPG standard. Those can serve until 2025. The original MIG-21 FL (MIG-21 PF or Type 77) was retired in December 2013; remaining MIG-21M aircraft (Type 88) are scheduled to be retired by 2015. Engines. The engines used in MiG-21 variants are listed in the table below. "* = limited (3-minute) "extra-power" reheat at altitudes 4000m (13,120 ft) or less." Armament. The following table shows the possible ordnance loads of various models of the MiG-21. The number in the pylons column indicates the number of stores carried per pylon. Avionics. Notes to table: <nowiki>*</nowiki> ADF =  Automatic direction finder; an asterisk by the name means there is no DME module present. <nowiki>**</nowiki> = An asterisk by the name indicates a rangefinding-only unit. General Specifications of MiG-21 variants are listed below:-