China's J-20 stealth fighter may soon fly with more powerful engines

Stealth fighter’s new WS-15 engine will close capability gaps with rival US jets and may enable deeper strikes on US bases

China’s J-20 stealth fighter has flown for the first time with indigenously-made WS-15 jet engines, marking what a potential game-changing upgrade for the type.

Last month, The Warzone reported that the test flight happened at the Chengdu Aircraft Industry Group’s main testing airfield, located next to its manufacturing facilities in its namesake city.

The Warzone notes that while blurry pictures make it difficult to ascertain whether the J-20 in question has WS-15 instead of WS-10 engines installed, nozzle serrations would be a reliable indicator, with the former having more nozzle serrations than the latter.

The report also notes that sound indicates whether the featured J-20 is equipped with new engines, noting that the test aircraft had a comparatively deep, dull rumble compared to WS-10-equipped units.

Although Warzone notes that a WS-15-powered J-20 flew in March 2022, it is believed that only one engine was fitted on the aircraft during that test. The report also claims China has mass-produced WS-10 and WS-15 engines, apparently overcoming technical bottlenecks in fitting the WS-15 to the J-20.

While the WS-15’s performance characteristics have not been disclosed, Asian Military Review noted in April 2023 that its thrust rating is most likely within the 150-kilonewton range, rivaling the US-made F-22’s Pratt & Whitney F119 engine.

In April 2022, Asia Times noted that initial J-20 models used less powerful Russian Saturn 117S and Chinese WS-10C engines, neither of which had enough power to reach desired speeds. The lack of thrust potentially made the type vulnerable in dogfights with US fighters.

Those underpowered engines may have also hindered the J-20’s upgrade potential, including in regard to directed energy weapons such as lasers or drone swarms.

The J-20 used Russian AL-31F engines for a period, but that was not a feasible option. Russia does not sell standalone AL-31F engines, so China had to purchase more Su-35s to get more engines.

However, an unnamed Chinese source quoted in the report said that longer range is the Su-35’s only advantage over the J-20, with the former’s radar, navigation system and other electronic components comparatively inferior.

The WS-15 may thus be a game-changer for the J-20, the type that is often deployed in the South China Sea with the possible aim of establishing air superiority in the event of a conflict with the US over the contested waterway.

China started J-20 patrols over the South China Sea in April 2022. As such, the J-20 also presents a formidable challenge to more advanced Southeast Asian air forces including Singapore’s, which operates the most advanced fighter fleet in the region.

At the same time, the J-20 will utterly outmatch weaker air forces in rival sea claimants like the Philippines, which has no multi-role fighters. However, China will likely deploy its J-20s only in the highest-risk scenarios, as they are likely too valuable to lose.

The J-20 may be the only Chinese aircraft able to match the US F-35, the only other stealth fighter operating in the region.

In March 2022, a close encounter between US F-35s and Chinese J-20s over the East China Sea demonstrated China’s impressive command and control over its fighters, although it is yet to be seen how China will employ its J-20 jets in the context of its anti-access/area denial (A2/AD) strategy.

Beyond the South China Sea, China could use its J-20s to strike at US bases in the First and Second Island Chains and interdict resupply efforts in the event of a Taiwan contingency.

In January 2022 that continental powers such as China emphasize ground-based air defence, with their fighters deeply integrated within their air defence networks.

China may be attempting to expand on that concept by integrating air power in joint offensive and defensive operations to protect critical infrastructure and naval and ground operations.

R Kalidas and other writers note in a 2016 article in the peer-reviewed Transactions on Innovations in Science & Technology journal that the US-made F-22 has a maximum range of 2,960 kilometers, compared to the J-20’s 3,400 kilometers.

With China’s air defence doctrine and the J-20’s long range, Kris Douglas and other writers mention that the J-20’s large internal volume, lack of autocannon and supercruise capability indicate that it is optimized as a long-range interceptor and air-to-surface attack platform.

In line with that, Military Watch reported in March 2022 that seven People’s Liberation Army-Air Force (PLA-AF) air brigades now deploy the J-20, with the 172nd Air Brigade in Tianjin, the 9th Air Brigade at Wuhu and the 1st Air Brigade at Anshan potentially deploying their aircraft in the East China Sea in proximity to the Korean Peninsula and Japan.

Moreover, Military Watch reported in June 2023 that the PLA-AF 131st Air Brigade based in Hainan has reportedly begun to operate J-20 fighters, with basing in that area an optimal location for the defence of Shanghai, Hangzhou, Guangzhou and Shenzhen, as well as for fortifying the island’s Longpo Naval Base, which serves as the hub for China’s nuclear submarine operations.

The report notes that Longpo Naval Base would be a likely target for US combat aircraft in a conflict scenario, making the deployment of the J-20 in Hainan a logical move to secure the strategic area.

Asia Times reported in March 2022 that China has fully militarized Mischief Reef, Subi Reef and Fiery Cross Reef in the South China Sea, will all three features now replete with airfields that can potentially house combat aircraft such as the J-20.

Those fortified islands can expand the offensive use of China’s airpower beyond Hainan and the country’s continental shores.

US bases such as Jinhae and Busan in South Korea, Okinawa in Japan and Guam in the Pacific may all now be in range of the J-20, with the aircraft able to conduct strikes far from China’s mainland and island airbases before retreating to the cover of its air defense network.