J-20 fighter jets attached to an aviation brigade under the PLA Air Force taxi in close formation during a flight training exercise on January 7, 2022. Photo: eng.chinamil.com.cn

Since China's J-20 stealth fighter jet switched to use domestically developed engines, the advanced warplane has proved its operability under extreme environments, including in regions at high altitude, under harsh cold weather and with high humidity and temperatures, a senior designer of the aircraft said on Wednesday.

This shows that the Chinese engines suit the demands of the J-20's operations in all regions across the country, experts said.

Gong Feng, the deputy chief designer of the J-20, shared some new insights on the J-20's switch to domestically developed engines in a speech published by a social media account affiliated with the Xinhua News Agency on Wednesday.

Gong said that the domestic engines unleashed the potential of the J-20, since the old engines were not customized for the aircraft, and it had to make compromises in its performance.

In addition to developing the engines, the J-20, including its airframe, structure, pipelines, electric circuits and subsystems, were redesigned, Gong said.

To ensure the upgraded J-20 can operate anywhere, Gong was tasked to conduct reliability tests and verification test flights, including in regions at high altitude, under harsh cold weather and with high humidity and temperature.

The tests went smoothly, Gong said. "I can proudly tell everyone, that the J-20 with Chinese engines has it all, both from the inside and outside." 

It was important to test the engine's performance under different environments across the country, Fu Qianshao, a Chinese military aviation expert, told the Global Times on Wednesday.

In high altitude plateau regions, the takeoff of the aircraft could be a problem because it requires high power from the engine, but plateaus have thin air; near the sea, high humidity could cause corrosion, Fu explained.

The tests proved that the domestically developed engine can satisfy the operating requirements under all environments across the country, allowing the J-20 to enhance its comprehensive combat capabilities, Fu said.

The Chinese People's Liberation Army (PLA) Air Force displayed J-20s equipped with domestically developed engines at Airshow China 2021, and analysts said the aircraft's production has accelerated thanks to the new engines.

"As an aircraft designer, I firmly believe that we can meet all of the PLA's requirements," Gong said.

He added that after the J-20, he is developing new types of aviation weapons and equipment, but without elaborating.