China’s J-20 received a new engine, but not equal to the F119 engines that power the F-22 and F-35.

At the Zhuhai Air Show 2021, the J-20 was spotted with the domestically-made WS-10C engine that showed the world China has solved some of its key problems with building high-performance military jet engines.

The WS-10 family of engines was designed to replace jet engines China had to import from Russia plus China’s inability to obtain the latest version of the Al-31F engine, the AL-41F1, used in the Russian Su-57 stealth fighter. In order to keep up with the fourth-generation engine, China has developed the WS-10C engine. The WS-10C engine has a thrust-to-weight ratio of over 8 tons and has vector control functions. It is currently equipped with the J-10C and J-16. While the WS-15 engine is still under development.

The WS-10C is an improved, and reliable, WS-10 that makes the J-20 more effective but not equal to the F119 engines that power the F-22 and F-35.

J-10C with WS-10B engine
J-10C with WS-10B engine

Both Russia and China are trying to make engines comparable to the F119. Thanks to the F119, the F-22 has high maneuverability, as well as supercruise capabilities. Putting the WS-10 and the more powerful WS-10C upgrade into production will allow China to replace the Russian AF-31 engine model used in most modern Chinese fighter jets.

Although the WS-10C engine has made considerable progress, there is still a big gap compared with the advanced engines of the United States and Russia. With the slow development of the WS-15 engine (5th gen engine to power J-20 and J-31), Chinese researchers have to continue to develop the potential of the WS-10B engine to meet the urgent needs of the J-20 fighter for high-thrust engines.

The WS-10C makes the J-20 more efficient, but not as good as the F-22 with its twin F119 engines. The Chinese version of the F119, the WS-15, is still working on fixing reliability issues. However, it must be admitted that China is somewhat overwhelming in terms of performance and reliability of Russian engines, and is starting to overtake Moscow in some categories.

Wrong decision already stoping J-20 production

In mid-2020 China revealed that its J20 stealth fighter had officially entered mass production. This was not the original J20 prematurely declared ready in 2017, but a much-improved J20B.

This comes two years after China admitted that J-20 production was stalled, and the manufacturer confirmed why that was the case. The relevant details were explained in a state TV report – partly to help businesses recruit the skilled workers needed to produce the J-20.

China has a shortage of skilled workers who can manufacture and assemble aircraft parts 
China has a shortage of skilled workers who can manufacture and assemble aircraft parts 

The labor shortage in China is largely due to the low birth rate in the decades following the introduction of the “one-child” policy. It was not until October 2015 that the Communist Party of China announced the repeal of the policy that had existed for the past 35 years in the country.

China’s aircraft manufacturing industry [in both the military and commercial sectors] is booming, while the number of workers who can make and assemble parts is in short supply.

Each stage of the construction of the J-20 requires a different number of skilled workers. Parts of the fuselage are made of special alloys, which take a long time to mold and then shape into complex structures.

Reason of Failure

Many aircraft components come from Chinese suppliers, who are still in the process of developing and perfecting their manufacturing capabilities. However, in general, the J-20 still requires a lot of foreign components, while the supply is very limited.

China also revealed that the J-20 development program cost $4.4 billion [as of 2018], with a construction cost of $110 million each. In addition to production difficulties, there are performance problems with the prototypes and six production models that the PLA Air Force received in 2018.

At that time, it was discovered that there were some potential problems in the production of the J-20. The main problems identified were related to the engine’s stealth capabilities, and the sophisticated materials added to the airframe, which made the radar’s ability to detect targets less effective.

Of these, the most obvious problem is the engine. In 2018, the WS-10 engine was installed for the J-20 as a temporary replacement, it was not efficient enough to support the aircraft’s supercruise capabilities.

J-20 with WS-10C engine
J-20 with WS-10C engine

However, everyone is waiting for the arrival of the WS-15 engine that may match the J-20. Only the WS-15  engine with a thrust-to-weight ratio of 10 can be equipped with the J-20 to fully exert its strength. That failure of WS-15 inherently a secret, but when this important engine model fails due to an explosion, the incident is difficult to conceal.

Initially, a more powerful and reliable version of the WS-15 for the J-20 was thought to be possible by 2020, but changes to the shape and mass of the WS-15 would require requires modifications to the J-20’s shape, and this requires a lot of testing to ensure that stealth is not affected.

The factory would have to install new or modified production equipment, and suppliers would have to do the same to produce the new airframe components. China claims most of those issues have been resolved by mid-2020, including the reliability issue of the WS-15.

However, this statement turned out to be too hasty. The WS-15 is one of China’s repeated frustrations and possibly more. Of course, some high-performance turbofans are more reliable than others. Western engine manufacturers have experienced this for decades as each new generation of engines

J-20 fighter aircraft
J-20 fighter aircraft with PL-15 AAM

is developed. China knows that and is doomed to repeat that process.


When the WS-15 engine will be fully ready, J-20 can operate with its full potential. According to data with WS-15 engine The J-20 fighter takes half of 5 tons of fuel. The built-in bomb bay can carry 6 PL-15 and 2 PL-10E air-to-air missiles. The total weight of these 8 air-to-air missiles is about 1.4 tons. At this time, the take-off weight of the J-20 is 23.4 tons.

Overall, the J-31 and J-20 are evidence that China is determined to develop its own high-tech military equipment. Beijing is trying to avoid the mistakes that Russia has made in this area. That requires them to have competitive design and develop the necessary supporting industries. All of this will take a lot of time and lead to many failures.

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