Engine Problems: How China Was Coerced Into Buying Su-35 And S-400

China has been developing a domestic turbofan engine since late 1990s, but failed to produce a reliable turbofan engine that could power domestically produced fighters. China developed WS-10 engine and its variants WS-10A/B/C are progressing with many setbacks. The faulty WS-10 was responsible for multiple J-10 and J-15 crashes. China’s dependent on Russian engines enabling Russia coercing China into buying military hardware China doesn’t need as China’s domestic variants are superior to Russian military hardware such as Chinese J-16 is far superior than Su-35, said Chinese defense expert in an interview with SCMP.

WS-10C Engines

In a separate video, released by the PLAAF for its pilot recruitment program, Chinese media outlets identified a J-20 that is equipped with domestically developed WS-10C engines (a modified version of its domestically-built WS-10 engine) instead of imported Russian AL-31Fengines, Global Times reported.

Designed with stealth capability, the WS-10C engines reportedly provide more powerful thrust than the Russian engines previously used on the J-20, since the Chinese engines use full authority digital engine control technology and improved afterburners.

Home Grown Engine For J-20

China will cease using the Russian engine currently fitted on China’s new generation J-20 stealth fighter jet, replacing it with an upgraded home-grown engine.

A military insider told the South China Morning Post Chinese aircraft engineers found their domestically built WS-10C, the modified version of the WS-10 engine, to be as good as the Russian AL-31F engines.

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“It’s impossible for China to rely on the Russian engine, because Russia asked China to purchase more Su-35 fighter jets in exchange for the AL-31F engine deals,” the insider, who requested anonymity, said.

China was the first overseas customer to buy Su-35 aircraft. The PLA spent US$2.5 billion buying 24 Sukhoi Su-35 heavyweight single-seat multi-role fighters, receiving the final shipment in late 2018.

“The key problem is – except for its longer combat range advantage – the radar, navigation system and other electronic components on the Su-35s are inferior to Chinese aircraft like the J-16 strike fighter.”

A photo taken by military enthusiasts circulating online late last year showed a J-20 fighter prototype with twin engines but with a new serial number “2021” and not powered by a Russian engine.

The online photo indicated China had produced a new batch of J-20 second-generation prototypes for flight tests, according to a report published on the War Industry Black Technology WeChat account by Shenzhen-based Quantum Defence Cloud, a military background company.

The military insider confirmed that the new J-20 prototype was powered by two WS-10C engines, but said the modified engine had remained a stopgap choice for the J-20.

“The use of WS-10C to replace Russian engines was caused by the failure of WS-15 to pass its final evaluation in 2019,” the insider said. The failure of WS-15 to pass the final tests was the main reason China signed an agreement with Russian Klimov to buy more than 100 RD-93MA engines for JF-17, expert believes.

The Covid-19 pandemic has affected modification work on the WS-15 in the past year, the insider said.China air force plays up J-20 strength as Taiwan tensions brew 15 September 2020.

A modified version of the J-20B entered mass production in June last year after Chengdu Aerospace Corporation (CAC), the developer of the J-20, set up a fourth production line in 2019. Each line has the capacity to make about one J-20 a month.

But these mass-produced J-20 will still be fitted with Russian engines because testing the WS-10C will take at least a year, according to the insider.

WS-10B Still Be Fitted To J-20B

Early in its deployment to the Chinese air force from 2017, the J-20 used the WS-10B, a variant of the WS-10, as a stopgap engine. The WS-10B is a modified version of the WS-10 Taihang engine, which was designed for the country’s fourth-generation J-10 and J-11 fighters.

Chinese engineers have been developing high-thrust turbofan WS-15 engines for the J-20 since 2006, but that work has fallen behind. Problems include an engine explosion during a ground running test in 2015.

Amid increasing security challenges posed by the United States since President Donald Trump came to office in 2017, Beijing decided to rush the country’s J-20 fighter jet into service ahead of schedule in 2017, because the Pentagon started deploying its fifth generation F-35s all-weather stealth multirole fighter to the Asia Pacific that year.

Macau-based military observer Antony Wong Tong said postponing the final launch of the WS-15 might affect China’s long-term aircraft development.

“The J-20 needs to shorten its transitional period and apply the WS-15 as quickly as possible because the US is expected to deliver their sixth generation aircraft in about a decade,” Wong said.

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