At the end of the 1960s, the PLAAF started looking into new light fighter designs to replace the J-6, which was based on the 1950s vintage MiG-19. Shenyang nr. 601 institute proposed an 11,5 ton light fighter design with cantilever wings and fuselage side-mounted air intakes, which in some ways resembled a smaller sibling of the Dassault Mirage F1. Although airframe design advanced fairly rapidly with a preliminary prototype finished in the early 80s, engine integration proved a difficult task. Both the recently acquired Spey Mk. 202 turbofan, built under license as the WS-9, and an indigenous engine developed by 606 Engine Design Institute, known as the WS-6, were considered to power the light fighter. As the fighter was to have a single engine, the PLAAF considered the 9,300 kg thrust WS-9 to be somewhat inadequate, since the design required the J-13 to have a thrust to weight ratio of at least 1:1. The WS-9 was supposed to become a 12,200 kg thrust turbofan, but development proved to be a very challenging task. As the J-8II programme started to flourish in the middle 1980s, the J-13 programme was accord lower priority, but in the wake of the new and very successful F-16 and Mig-29 programmes abroad, the programme continued nonetheless. In 1992 the PLAAF finally put a stop to the project because of the progress of the J-10 programme and the access to Russian Su-27 Flankers and engine technology.
WP-15
In 1982, China received a handful of MiG-23MS fighters from Egypt, in exchange for a 'friendship price' for the recent F-6 and F-7 fighters sold to the Egyptian air force. Apart from serving the J-8II project with a successful engine inlet architecture, which resulted in the final success of the 'Finback', the deal also provided China with a new engine design. The Tumanski R-29, with a dry thrust of 10,000 kg, was also considers to be a viable candidate for the J-13 programme, and was to be produced internally with the WP-15 name. Again, the programme didn't flourish, mostly because of the availability of modern Russian turbofan engine technology from 1990 onwards.
