WS-20 high-bypass turbofan

Weak aero-engine technology has always been a bottleneck restricting the performance of Chinese military aircraft, but in recent years, more breakthroughs have been made in related fields. With the maturity of a large number of new types of aviation, the "heart disease" problem of large Chinese aircraft is expected to be completely eradicated.

Turbofan-20 (WS-20) is a large bypass turbofan engine with a thrust range of 13,000 to 16,000 kilogram-forces (kgf). This engine is the turbofan-20 turbofan engine independently developed by China based on the "Taihang" engine. The engine will be mainly used to transport -20 large transport aircraft. In the future, it will also be used as the main power for large passenger aircraft, new dual-engine medium transport aircraft, and second-generation long - range anti-submarine patrol aircraft.

On August 2, 2014, Weibo netizens posted a photo of a test flight of the Yier 76 at the China Test Flight Academy. A new large bypass ratio turbofan engine is installed on the inside of the left wing of the aircraft, which is suspected to be the "China Heart" WS-20 (turbine fan-20) engine of the domestic large transport aircraft Yun-20. This is one of the few appearances of this type of engine. On June 15, 2016, Internet media exposed a satellite picture of an airport, which showed that an Il-76 test machine with 4 turbofan-20 engines was parked at the airport. A transport aircraft can be equipped with 4 new engines being trial-produced, which may indicate that the reliability of the Chinese turbofan-20 engine has been better solved, and the turbofan-20 is not far from the final production.

By early 2016 Avic Engine was working on advanced development of the WS-20, a high-bypass turbofan that had been known as the power plant of the Y-20 military airlifter, and had been promoted unsuccessfully as a Chinese engine for the C919 airliner. A smaller turbofan, the WS-20-9, was planned for the Comac ARJ21, which initially used the GE CF34-10. The Chinese industry had previously proposed to fit that regional jet with an engine called WS-12C of 17,600 lb. thrust.

For turbofan engines installed on subsonic aircraft, the larger the fan diameter, the larger the bypass ratio, the higher the efficiency, the greater the thrust, the lower the fuel consumption, and the lower the noise. Fuel consumption is a key indicator, which directly determines the performance of transport / passenger range, load and other aspects. From this perspective, the D-30KP-2 / turbine fan 18 only solves the problem, and the Yun 20 needs a more advanced engine.

the Taihang FWS-10 small bypass ratio turbofan engine developed by China is developed on the basis of the imported CFM-56 large bypass ratio turbofan engine. Both core engines are the same, so it can be based on Taihang Developed a new domestic turbofan engine with large bypass ratio.

It is reported that China's new generation of large ducted turbofan engines adopts this approach. Its number is turbofan 20, which uses an improved FWS-10 core machine, plus a domestically developed Dahan. Doubi fans, while optimizing the design of high-pressure turbines, low-pressure turbines, fans / booster stages, in addition to the use of full authority digital electronic control system (FADEC), to further improve engine performance and reliability. It is generally predicted that the comprehensiveness of turbofan 20 can reach the level of CFM-56, which is significantly better than that of D-30KP-2 engine.

According to the indicators of CFM-56, compared with D-30KP / Turbofan 18, turbofan 20 has reduced weight and cruise fuel consumption. In terms of engine cruise fuel consumption, CFM-56 is 0.57, while D-30KP-2 / Turbofan 18 More than 0.7. Therefore, for the Yun 20, after the turbo fan 20 is replaced, due to the improved engine performance, its range and load can be effectively improved. In particular, it should be noted that the maximum take-off thrust of the newer models of CFM-56 can reach 15 tons. The index is close to the F117-PW-100 turbofan engine equipped with the C-17, which has a take-off thrust of about 17 tons, so the turbofan 20 can be upgraded according to this standard, thereby providing a power reserve for the upgrade of the Yun-20.

A WS-20 demonstrator had been run since 2010. A further succession of five core designs was supposed to be tested from 2015 to 2019. The program envisioned moving ahead with both 33,000 lb. and 15,000 lb. turbofans simultaneously, with a design freeze due in 2018, first engines to test in 2019 and entry into service on the C919 and ARJ21 in 2022 – the year originally targeted for the CJ-1000.

This turbofan engine with large bypass ratio remains in the flight test flight stage and will be put into use "within the next 5 to 7 years" - aroudn the year 2025, possibly. So far, China has become the fifth country after the United States, Britain, France, and Russia to independently develop high-performance turbofan engines with high bypass ratios. This type of engine has not only filled an important gap in China's aero engine field, but also served as a milestone on the road to the development of China ’s aero-engines. It can be said that over this threshold, China’s aero-engines will officially enter the “fast track” for development, just like breaking through that layer of “window paper” and a series of advanced technologies were conquered one after another.

At present, in addition to developing turbofan-20 engines for military and civilian use, China is also developing a Yangtze River-1000A engine with C-919 civil aircraft as the target, and plans to produce domestically-leading LEAP-X engines in the world. In addition, China is already studying the next generation of advanced large bypass ratio engines with a thrust of 200 to 400 kilonewtons, and various signs indicate that the spring of China's large bypass ratio engines has arrived.

WS-20 is the military code and the commercial code is SF-A. Designed and developed by AVIC Commercial Aircraft Engine Co., Ltd., a subsidiary of China Aviation Industry Corporation. The large bypass ratio turbofan engine can be used as the power of large military and commercial aircraft. It consists of a 1-stage fan, a 3-stage supercharged compressor, a 7-stage high-pressure compressor, a short-ring combustion chamber, a 1-stage high-pressure turbine, and a 3-stage low-pressure turbine. Convergence nozzle and full authority digital control (FADEC) system.

The careful observer will note that these two engines, both represented as "WS-20", are evidently two different and unrelated designs. One or the other might be the actual WS-20, but one is surely not.