JOHNATHON WENG JDW Correspondent
Tianjin
* China's efforts to develop a turbofan engine stem back to the 1960s
* The testing of the WS10 still leaves production hurdles to be overcome
China's WS10 turbofan engine has had a long history going back to the start of the WS6 turbofan programme in the 1960s, but news that the engine has undergone testing in a Sukhoi Su-27-derived fighter reveals a new maturity in the programme.
The level of development of the engine was revealed in November 2005 in a public statement by the government-owned press that the design had been finalised after two decades of research and development.
The WS10 is derived from the earlier WS6 variant, which was abandoned after completion as an engine - 20 years and two engine generations later - in the 1980s.
The expertise of 606 Engine Design Institute in developing the WS6 and the 1982 acquisition of CFM-56 engines, which are based on the compressor of the F101-GE-102 engine used in B-1B bombers, supported the development of the WS10.
The WS10 work was conducted under the High Performance Propulsion System Preliminary Development plan and in 1989, almost 10 years after WS10 work started, three key engineering challenges were identified: a seven-stage high-pressure compressor; a short annular combustor with air blast atomiser; and air-film cooling turbine rotor blades.
It was planned that the development of these requirements would lead to a Medial Thrust Demonstration Turbofan Core Engine (MTDTCE) and eventually a demonstration engine. The China Gas Turbine Establishment led the development work on the engine and in 1992 major component manufacturing blueprints were drawn up.
Military Industrial Plant 403 manufactured the MTDTCE with the involvement of 21 Chinese factories and research organisations. Trial production began in March 1992.
In December 1992 the engine was powered and nine days later the engine reached maximum speed within testing parameters.
Indigenous development and the use of Russian aero-engine experts, as well as knowledge of the AL-31F engine which powers the Su-27, drove further development.
The 606 Engine Design Institute then received a Sukhoi Su-27 (Chinese designation: J-11) as a test platform from the People's Liberation Army Air Force.
The use of the engine in the test aircraft presented its own challenges - the oil tank and afterburner nozzle are larger - but the weakness of the Chinese military industries and shortage of investment exacerbated the problems.
The programme stumbled along between 1992 and 1997 and was further impeded by the move from a state-controlled economy to a more free market economy. In 1997 an accident in engine testing delayed the programme again.
In 2001 and 2002 the WS10 was tested on an Su-27 and in 2003 the People's Liberation Army's daily newspaper said that flight tests were under way. An engine failure during a flight in July 2004 put the programme in jeopardy but the aircraft returned on a single engine and an investigation reported that a bearing failure was to blame.
The WS10 was declared close to prototype stage on 11 May 2005 and this was followed by endurance life testing and full life testing. On 10 November the WS10 passed full life testing and then completed 40 days of trials without failure.
Despite the success in developing the engine, which will be manufactured by Liming Corporation, the powerplant will need to overcome manufacturing challenges if it is to be produced at a worthwhile rate.
Issues remain about production efficiency and quality control and any effort to improve these areas is likely to be hamstrung by bureaucracy. However, the development of the engine has created an improved industrial base and expertise.
