Built only in small numbers up to 1987, the J-8 resembled little more than a scaled-up twin-engined MiG-21 and had only a limited combat capability. Revealed in 1984, the J-8 l Finback-A was an all-weather development with a basic fire-control radar, 23-mm cannon and missile armament.
The J-8 I first flew in prototype form in 1981 and was followed by around 100 production aircraft (including J-8s upgraded as J-8 Is). In 1981 work began on the much revised J-8 II Finback-B with uprated engines, replacement of the nose inlet by two lateral inlets, and the addition of a monopulse search radar. The first of four J-8 II prototypes made its maiden flight in 1984 and these have been followed by at least 24 production J-8 IIs.
SAC and Grumman co-operated to develop an improved J-8 II with modernized avionics, radar and weapons systems but this programme was terminated by the USA in 1989. Despite this setback, SAC has developed the upgraded F-8 IIM that represents a major advance. Installation of a Phazotron Zhuk-8 II multi-mode pulse-Doppler radar gives compatibility with R-27/AA-10 Alamo air-to-air missiles - the first beyond visual range weapons to be associated publicly with a Chinese combat aircraft. Other possible air-to-air missiles may include an air-launched variant of the LY-60 SAM (itself a weapon that uses technology from the Italian Aspide) and the Russian Vympel R-77/AA-12 Adder. The F-8 IIM also features a hands on throttle and stick-equipped cockpit and uprated engines.
Other proposed indigenously-developed improvements include low-altitude navigation and forward-looking infra-red/targeting pods, integral jamming system, a digital fly-by-wire flight control system and helmet-mounted sight. The first rebuilt F-8 IIM made its maiden flight in 1996 and an unknown number have been built o date.
The F-8 IIM may have been developed for export, as an upgrade for the PLAAF's J-8s, or simply as a testbed to integrate technologies already in place on Chinese Su-27s on an indigenous airframe. Around 100 J-8 I/IIs currently serve with four PLAAF regiments; the type may also serve with the PLAN-AF.