The J-8 began development in the mid 1960s as a fairly late response to new high-speed, high-altitude threats from NATO aircraft. The J-8 was an entirely new design, developed from the J-7 (itself a MiG-21 copy). The basic configuration of the MiG-21 was carried over, while a second Chinese-built Tumansky R-11 engine was mounted in the airframe. Initial variants would retain the nose-mounted intake, giving the J-8 the appearance of a larger, fatter MiG-21. Despite the design calling for a solid nose to house a radar, Shenyang’s unfamiliarity with such designs meant that these initial J-8s would be vastly less capable than what was required.
The first J-8 took flight in 1969, demonstrating performance similar to the Su-15. While the initial J-8 design continued testing and prepared for production, Shenyang continued to develop the design into the more capable interceptor China was in need of. Developments eventually led to the J-8II, with a nose-mounted radar and side-mounted intakes, giving the design an appearance nearly identical to the Su-15. Meanwhile, the J-8I, the initial variant, entered service in 1980, with disappointing performance. It was limited to short-ranged IR missiles, and demonstrated performance comparable to decade-old Soviet designs. Production of the J-8I was cut short, and the aircraft were replaced as soon as the newer J-8IIs became available.About 200 were built before attention switched to the more capable J-8-II.
Early in 1986 US Government approval was given to an unprecedented agreement, under which $500m worth of modern avionics would be sold to China for use in its next-generation interceptor, the J-8-II. Fifty-five sets of equipment will be supplied, each including an interception radar, an inertial navigation system, a headup display, and mission and air data computers.
In May 1984, the first J-8II took flight, marking a major improvement over the J-8I. Changes to the forward fuselage not only included radars and intakes, but also the cannon armament and weapon systems. It has relocated fuselage intakes, a ventral fin which folds to starboard for landing, and twin Wopen 13A-II powerplants probably developed from the Soviet Tumansky R-13-300 engine. Systems aboard the J-8II provided the PLAAF with a much more capable interceptor, while it still lagged behind contemporary western designs. The J-8II was rushed into service as soon as possible, replacing the obsolete J-8I. Shenyang continued to develop the systems of the J-8II, with hopes of eventually mounting an American AN/APG-66 radar on the design. However, when the backlash from the 1989 Tiananmen Square incident hurt Sino-American relations, less capable domestic systems were used.
The J-8II fully replaced the J-8I by the 1990s with a production run of over 300 aircraft. While performance leaves much to be desired, it has proved more than capable for the few interceptions they have had to make since the end of the Cold War. Shenyang has continued to upgrade the J-8II’s systems, attempting to make the design as competitive as possible. However, fire control systems and radars still seem to lag behind the West. The only notable incident involving the J-8 was the 2001 Hainan Island incident, where a J-8II intercepted a US EP-3 just outside Chinese airspace, colliding with the aircraft. While the Chinese pilot was killed, the EP-3 survived the collision, and was forced to make an emergency landing in China. The J-8II was slated to be replaced by the more modern J-10 and J-11 fighters.