Taking due account of the Vietnam War experience of operating fighters from ad hoc ‘ambush airstrips’ to intercept US strike aircraft formations, in 1969 the PLAAF posed a requirement for a light tactical fighter having short take-off and landing (STOL) capability. The Shenyang J-11 was to be a replacement for the obsolescent J-6 and, to a certain extent, the Q-5 attack aircraft.
Working together with the No. 601 Research Institute, the Shenyang Aircraft Factory explored three alternative concepts. The first one envisaged a powerplant of two uprated WP-6 III afterburning turbojets; however, this engine was getting long in the tooth and may not have provided the required speed. The second version was built around a single WP-7 III afterburning turbojet; however, with the specified maximum take-off weight of 7,000 kg (15,430 lb) the thrust/weight ratio would be marginal, severely limiting the fuel load and ordnance load.
The third concept was based on an afterburning turbofan which did not yet exist. The designers proposed developing an afterburning version of the Rolls-Royce Spey 512 powering the Hawker Siddeley HS.121 Trident airliner. After a lengthy appraisal the third concept was selected for further development of a fighter designated Shenyang J-11.
Preliminary development was completed in late 1971, and the resulting aircraft bore a striking resemblance to the French Dassault Mirage F1. It had sharply swept shoulder- mounted wings with a leading-edge dogtooth; the conventional tail surfaces featured low-set stabilators and a small ventral fin. The single engine breathed through semi-circular lateral intakes with half-cone centrebodies. The long pointed nose was to house a Type 645 fire control radar. The armament consisted of two 30-mm cannons and up to four PL-2 or PL-5 AAMs, or air-to-surface weapons.
The Shenyang J-11 was to be 15.76 m (51 ft 0 in) long and 4.7 m (15 ft 5 in) high, with a wing span of 8.695 m (28 ft 5 in) and a normal TOW of 8,700 kg (19,180 lb). The aircraft was to have a take-off run of only 500 m (1,640 ft), a range of 2,300 km (1,430 miles) and a maximum climb rate of 197 m/sec (38,770 ft/min) at 5,000 m (16,400 ft).
The project did not materialise – for several reasons. Firstly, the intended powerplant proved unobtainable – it was impossible to purchase more Spey 512s or reverse-engineer the engine at that stage. Secondly, the competing J-12 project was much more advanced in its development. Hence the Shenyang J-11 programme was terminated, the designation being reused much later for a Sukhoi Su-27SK derivative – ironically, also built by Shenyanq.