Last week, as the Chengdu J-20 entered into service, China became the second nation on the planet to field a fifth generation fighter platform… or at least that’s what they’ve claimed. New reports in Chinese media, however, indicate that issues with the advanced fighter’s intended power plant, combined with the Chinese government’s hurry to get the J-20 into service, may have actually cost the stealthy fighter its distinction as a true fifth generation platform.

According to sources in the South China Morning Post, the People’s Liberation Army rushed the J-20 through the final stages of development last year, prompted by heightening tensions throughout the region as a result of China’s expanding claims over the South China Sea. The advanced fighter platform’s design phase was already dramatically expedited, many believe, by using stolen plans for America’s advanced fighter, the F-22, accounting for the striking resemblance between the two aircraft.

Lockheed Martin F-22 Raptor top, Chengdu J-20 bottom.

Experts have long attested that, despite their similarities, the J-20 likely lacks the same stealthy profile employed by the F-22, in part due to the stabilizing canards added to the plane, but also thanks to still-classified methods utilized in the F-22’s construction. That potential gap in stealth capability, however, is not enough to cost the J-20 its position as the third ever fifth generation fighter to take to the skies… instead, it would appear, the issue lies with its engines.

The J-20’s intended engines, dubbed WS-15s, were purpose built for the new platform, but have suffered repeated setbacks that seem to be tied to their ability to mitigate the immense levels of heat they produce while in operation.