China’s Engine Boast Meets Brutal Reality

China is loudly boasting that its new J-20 engine now out-muscles America’s F-22, but the fine print tells a very different story for U.S. air power and our security.

Story Snapshot

China’s WS-15 engine reportedly gives the J-20 F-22-level thrust and true supercruise, at least on paper.
Key numbers, like “40,000 pounds” of thrust, mostly come from Chinese sources and friendly outlets, not U.S. testing.
Even Chinese-linked experts say the WS-15 still lacks U.S. engine endurance and is not ready for full mass production.
American F-22 and F-35 engines still lead in proven reliability, lifespan, and advanced designs like adaptive cycle technology.

China’s New Engine Claim: More Thrust Than the F-22?

Chinese state-linked media and several defense outlets now claim the WS-15 engine on the J-20 can push out around 180 kilonewtons of thrust, roughly 40,000 pounds, per engine in afterburner.^[1] That figure would edge out the Pratt and Whitney F119 engines on America’s F-22 Raptor, which sit near 35,000 pounds of thrust. These reports frame the WS-15 as the long-awaited fix for the J-20’s weak Russian engines and as a sign that China has finally caught up in raw power.^[1]

Other reports say early WS-15 prototypes hit between about 161 and 180 kilonewtons with afterburner and were designed from the start to give the J-20 a true high-thrust, supercruise-capable powerplant.^[3] Supporters argue that this level of thrust, plus low-bypass turbofan design, puts the J-20 in the same thrust class as both the F-22’s F119 and the F-35’s F135 engines. On paper, that looks like a major step up from the older Russian AL-31 engines that once held the J-20 back.

Supercruise and “Closing the Gap” With U.S. Air Power

Defense reporting says the WS-15 is built to give enough dry thrust for the J-20 to supercruise, which means flying supersonic without using fuel-hungry afterburners.^[1] Estimates place that supercruise speed in the Mach 1.3 to 1.5 range or higher, which would move the J-20 much closer to the F-22’s famous ability to sprint fast, stay stealthy, and still hold fuel in reserve.^[1] The Pentagon’s own China Military Power report even anticipated that a WS-15 upgrade would add supercruise and greater internal missile load to the J-20 fleet.^[4]

Several open sources also note that the WS-15’s higher thrust is meant to unlock the J-20’s full airframe, including better climb rates, acceleration, and high-altitude performance.^[1] With more power, the jet can carry long-range missiles like the PL-15 with greater energy, which matters in a Pacific fight over long distances.^[9] As a result, many commentators now describe the WS-15 as ending the J-20’s “Achilles’ heel” and turning it into a true top-tier fifth-generation threat in the skies over Taiwan and the wider region.^[9]

Durability, Reliability, and the Maturity Gap

Beneath the hype, the biggest red flag is not raw thrust, but engine maturity and lifespan. A widely cited former instructor from China’s People’s Liberation Army reportedly said the WS-15 does not yet match American engines in endurance, which can exceed 500,000 flight hours in some cases.^[3] He further described the WS-15 as an “experimental success” that still needs more tests and improvements before it is ready for true mass production and long-term frontline service.^[3]

That same analysis stresses that the older American F119 still outruns the WS-15 in categories that matter for a real war, including thrust-to-weight ratio, bypass ratio, stealth characteristics, and engine life span.^[3] Western commentary also points out that while China announced serial production of the WS-15 in 2023, questions remain about time between overhauls, maintenance demands, and how many engines can survive hard use in high-temperature, high-stress operations.^[8] These are exactly the areas where Russian and Chinese engines have historically lagged.

Is the WS-15 Really “Most Powerful”? The F-35 and Future U.S. Engines

Even if the 180 kilonewton claim is accurate, the WS-15 is not clearly the strongest fighter engine in the world. Chinese and Western technical writeups acknowledge that America’s F135 engine on the F-35 already reaches about 191 kilonewtons of thrust, putting it above the WS-15 in pure power.^[1] Analysts note that the F135 also leads in thrust-to-weight ratio, fuel efficiency, and reliability, and it has been proven in real combat operations rather than test photos and staged flyovers.^[3]

J-20A with the WS-15 engine. As production continues to accelerate, we can confidently say the J-20 is approaching and will soon exceed the annual production rate of the F-35. pic.twitter.com/paCe2YRkOO

— Ababeel (@AbabeelMilitary) June 16, 2026

On top of that, the United States is now pushing into adaptive cycle engines, such as the experimental XA100 and XA101 class designs, which aim to deliver more thrust, better fuel efficiency, and much greater thermal management than legacy engines. Pentagon-backed material and industry analysis already pitch these adaptive engines as the next leap beyond both the F119 and the WS-15.^[11] That means while Beijing is celebrating “parity” with America’s last generation of propulsion, U.S. engineers are already working on the next step.

Fog of War: Why Numbers Alone Do Not Tell the Whole Story

Much of the data about the WS-15 comes from Chinese makers, friendly commentators, or crowdsourced forums, not from hard independent testing.^[1] This follows a familiar pattern in air power debates, where one side touts a new engine or airframe as a breakthrough and the other stresses that reliability, sustainment, and combat integration are what really win air wars.^[11] U.S. Air Force research on air superiority makes clear that propulsion is only one piece alongside sensing, weapons, and networked command systems.^[11]

For American readers, the bottom line is clear. China is getting closer in some areas, and its J-20 with WS-15 should not be dismissed. But the loud claim that Beijing has out-powered the F-22 masks deeper questions that favor the United States: proven engine life, maintenance chains, pilot training, and the next wave of American adaptive engines already in development. Those are the quiet advantages that keep U.S. air superiority ahead—if Washington stays focused and does not let complacency or budget cuts erode them.