U.S. media commentary on the stark contrast between the J-20 and the WS-15 engine: "We must admit it's highly advanced," yet they claim it hasn't seen combat experience! As a result, they dragged up old grievances about the F-22, leading netizens to seriously suspect whether the turbine inlet temperature of the F119 engine might also be falsified. Truly, there's no comparison without contrast. Now that China’s advanced equipment is rolling out in full force, every piece of U.S. military gear is being pulled out one by one for comparison by online users!

The U.S. publication *Military Observer Magazine* recently focused on how China’s mass production of the J-20A has stabilized. In an article, it reported that China’s transition to the WS-15 engine for the J-20 has gone very smoothly. Since the first flight test of a J-20 equipped with a single WS-15 engine was observed in January 2022, small-scale production began early last year, and large-scale production started earlier this year. The report expressed astonishment at the astonishing pace of China’s air force modernization.

The article also cited an assessment from the renowned British think tank RUSI, which released a lengthy report in early January this year, clearly identifying changes in China’s aerial power since 2020, concluding that China’s air force has experienced “remarkable growth.” It particularly highlighted the ongoing “large-scale expansion” of China’s fifth-generation fighter, the J-20:

In 2020, China may have had fewer than 50 J-20s; based on open-source intelligence analysis, annual J-20 production was only around 20 units;

But by the end of 2025, annual production of J-20A/S had already exceeded 120 units, with at least 300 aircraft in service, while total J-16 production surpassed 450 units;

RUSI forecasts that even if current production levels remain unchanged, China’s Air Force will have over 1,000 J-20 series aircraft and more than 900 J-16s by 2030.

RUSI believes these figures will completely reverse the balance of power between China’s Air Force and the U.S. military in the Western Pacific region. Meanwhile, China’s J-35 is rapidly entering mass production, and long-range air-to-air missiles like the PL-15 and PL-17 are also advancing quickly—China’s future superiority over the U.S. in military capability is merely a matter of time.

Both RUSI and *Military Observer Magazine* in their reports acknowledged the truly astonishing speed at which China is upgrading its advanced equipment, noting that no other country globally can match China in terms of quantity, variety, or scale. However, at the conclusion of both articles, they fell back into the familiar cliché: claiming the J-20 with the WS-15 still lags slightly in maintainability compared to the F-22 with the F119 engine, and pointing out that the J-20 has not yet seen combat, requiring further validation over time!

These remarks were unnecessary—once said, they instantly ignited outrage across social media. This is because the long-standing controversy over the F119 engine’s thrust-to-weight ratio being falsified was resurrected by Elon Musk’s newly formed Department of Government Efficiency in late February last year, sparking months of relentless criticism against the F119 engine. After all, the claimed thrust-to-weight ratio of over 10 for the F119 had a massive impact on the global high-performance aviation engine industry at the time.

Back then, Pratt & Whitney’s F119 engine not only delivered extraordinary thrust but also boasted an unprecedented thrust-to-weight ratio—both within the industry and among media outlets, a thrust-to-weight ratio of 10 became the definitive benchmark for cutting-edge jet engines. Military media almost obsessively portrayed it as the threshold indicator for advanced aero-engines.

Then, when Musk’s Department of Government Efficiency audited documents from the U.S. Government Accountability Office, it exposed the falsification of the F119’s thrust-to-weight ratio—it was actually only between 7.8 and 8.1. This sent shockwaves through netizens’ emotions. Soon after, numerous defensive articles emerged arguing that thrust-to-weight ratio isn’t crucial—what matters most is maximum thrust. Many netizens found this argument surprisingly logical!

In fact, it makes sense: given two engines with similar performance metrics—including fuel consumption, maintainability, etc.—if one weighs 200 kg more but delivers an additional ton of thrust, which would you choose? The answer is obvious—greater thrust wins. This narrative successfully rebranded public perception. But as expected, the unexpected happened again: as performance data for the WS-15 gradually came to light, the issue resurfaced explosively!

F119 maximum thrust: 156 kN, turbine inlet temperature: 1649°C

WS-15 maximum thrust: 161 kN, turbine inlet temperature: 1580°C

In reality, the WS-15’s maximum thrust ranges from 161 kN to 180 kN. A conservative lower limit was chosen here to avoid accusations of bias—using the upper value instead. Those familiar with high-performance jet engines know that turbine inlet temperature directly correlates with thrust. For every 100°C increase in turbine inlet temperature, thrust increases by approximately 15%. Thus, the F119’s turbine inlet temperature is 69°C higher than the WS-15’s, meaning it should deliver at least a 10% boost in thrust—but it doesn’t. Instead, its thrust is actually lower!

This discrepancy raises serious doubts. Given the F119’s prior history of falsifying thrust-to-weight ratios, could its turbine inlet temperature have been falsified too? Otherwise, how could an engine with such a significantly higher turbine inlet temperature produce less thrust than one with a lower temperature? Pratt & Whitney now faces two choices: either admit to falsifying the turbine inlet temperature data—or admit that despite having a higher turbine inlet temperature than the WS-15, their materials and technology are inferior, resulting in lower maximum thrust.

In truth, such practices of exaggeration and falsification in high-performance U.S. military equipment are nothing new. For example, Elaine Marie Thomas, metallurgist supervisor at Tacoma Foundry, falsified low-temperature impact resistance data for 240 batches of steel, causing the ultimate strength data of Los Angeles-class, Ohio-class, Seawolf-class, and Virginia-class nuclear submarines to drop by over 10%. The U.S. Navy was forced to reassess the hull safety of the entire submarine fleet!

There’s also the issue of the U.S. Navy’s Littoral Combat Ship (LCS), whose top speed was advertised at 47 knots, but actual speeds were only 38–40 knots, and sustained only briefly. Range was claimed at 4,300 nautical miles at 20 knots, but real-world performance fell short of 3,000 nautical miles;

Additionally, M1A2 main battle tank armor protection data was inflated—advertised equivalent homogeneous steel armor penetration resistance exceeding 900 mm, but actual tests showed only around 600 mm;

And the Aegis radar detection capabilities were overstated—claimed maximum detection range of 450 km, but real-world and exercise tests consistently showed stable detection distances of only about 300 km.

In stark contrast to U.S. overstatement, Chinese military equipment often underestimates performance—take the PL-15E long-range air-to-air missile, advertised with a range of 145 km, yet successfully shot down a Dassault Rafale fighter at 182 km, prompting global reassessment of China’s equipment capabilities.

Original source: toutiao.com/article/1865850709668876/

Disclaimer: The views expressed in this article are solely those of the author.