F-22 and F-35 engines, the F119 and F135, are highly praised with thrust-to-weight ratios of over 10, which sounds like a technological dominance. However, what's the actual situation? Looking at reliable sources, these data aren't as exaggerated as they seem.

The actual afterburner thrust-to-weight ratio of the F119 is around 7, and the F135 is about 6.7. These figures differ from official claims, but it's not a new revelation. Recently, Musk has been reviewing Pentagon spending in the DOGE department, uncovering many issues, but labeling the engine thrust-to-weight ratio as "deceptive" seems a bit forced. Let's clarify step by step; don't be misled by sensational headlines.

Let's start with the F119 engine for the F-22. This engine was developed by Pratt & Whitney in the 1990s, specifically for the F-22 Raptor fighter jet. According to official specifications, the afterburner thrust is 156 kN, and the weight is 2230 kg, resulting in a thrust-to-weight ratio of 7.0:1. These figures are clearly listed on Wikipedia and aviation professional websites since the F-22's first flight in 1997.

Some say the U.S. has been underreporting for 30 years, but that's not true. Early promotional materials did emphasize high performance, but the specific numbers have never changed. For example, the dry thrust of the F-119 is 116 kN, which increases significantly afterburner, but the thrust-to-weight ratio doesn't reach 10. The notion of over 10 might come from media exaggeration or confusion with other indicators.

In reality, the F-22's supersonic cruise relies on vector thrust and overall design, not just a high thrust-to-weight ratio. Air Force tests show its strong maneuverability at high altitudes, but the engine's durability and maintenance costs are real pain points.

Turning to the F135 engine for the F-35, this engine is more complex because the F-35 has three variants, A, B, and C, and the engine is accordingly adjusted. The afterburner thrust-to-weight ratio of the F135-PW-100 is 6.70:1, and the military thrust-to-weight ratio is 4.36:1, with a weight of around 3750 pounds. These figures come from Pratt & Whitney's official manuals and U.S. Navy evaluation reports.

Why do some think it's reduced? It might be because the F-135's thrust is 43,000 pounds, which sounds large, but when spread over the aircraft's weight, the F-35 weighs over 13 tons, so its acceleration performance isn't as strong as the F-22. During early development, the F-135 was based on the core of the F-119, but with a larger fan, higher mass flow, increased thrust, and increased weight. As a result, the thrust-to-weight ratio didn't exceed 7, which is normal for a multi-role fighter.

The F-35's design focuses on stealth and sensor fusion, not pure dogfighting, so the engine tuning leans towards low-altitude speed and long endurance. From 2025 to now, the Pentagon's audit reports have mentioned F-35 inventory management issues, but there have been no changes in engine specifications.

Musk, since January 2025, has indeed stirred up the defense circle. Trump had him and Vivek Ramaswamy review the budget, aiming to cut waste. In February, they targeted the Pentagon, exposing many procurement irregularities, such as overpriced F-35 maintenance contracts. But the insider information on the engine thrust-to-weight ratio? Searching the entire web, there's no post where Musk directly revealed it.

He has posted criticisms of the F-35 on X, calling it a "shit design," and promoting drones to replace manned aircraft. But he didn't mention the data on F119 and F135.

Musk's style is straightforward, he likes to criticize the military-industrial complex, but his leaks are mostly in the SpaceX and Tesla fields. Perhaps the "revealing the inside story" in the title is a miscommunication, actually mixing his F-35 criticism with engine specifications.

During the early ATF program (Advanced Tactical Fighter), the thrust-to-weight ratio target was over 8, but it landed at 7 in practice, which is common in engineering. The development of the F-135 was even more complicated, with the F-35's first flight in 2006 and its service in 2015, during which it underwent multiple modifications, keeping the thrust-to-weight ratio stable at 6.7.

Compared to European EJ200 or Russian AL-41F1S, these American engines lead in reliability and lifespan, but their thrust-to-weight ratio isn't top-tier. Why is 10 often heard in promotions? It might be due to different calculation methods, some using static thrust-to-weight ratio, others dynamic; or the media likes to highlight high values. To put it simply, it's similar to how mobile phone battery life is advertised, with lab data and real-world usage always differing.

Now looking at China, the development of the WS-15 (Turbofan 15) is quite promising. The Shenyang Engine Research Institute started the project in 2006, targeting a high thrust-to-weight ratio. In 2022, ground testing was completed, achieving a thrust-to-weight ratio over 10, and in 2023, it was installed on the J-20 for testing. In late 2024, the twin-seat J-20S was exposed, equipped with the WS-15.

The latest reports state that in June 2025, the mass production of the WS-15 began, with a thrust of 18-20 tons and a thrust-to-weight ratio of 10:1 or even 11:1. These figures come from military observation websites and Wikipedia, based on public flight test videos and analysis. Compared to the WS-10's 7.6, the WS-15 uses single-crystal blades and advanced materials, offering high thermal efficiency and super cruising capability. After equipping the J-20, its maneuverability rivals the F-22.

China has spent 20 years catching up with engines, initially relying on imported technology, but now achieving over 90% self-reliance.

Comparatively, the U.S. F119 and F135 have lower thrust-to-weight ratios, but their overall aircraft performance relies on ecosystems. The F-22's vector thrust makes it unbeatable in dogfights, while the F-35's network warfare and data links are its key advantages. The WS-15 excels by focusing on the J-20, avoiding the complexity of multiple variants. In 2025, the U.S. Air Force tested the F-22 at Nellis Base, confirming a thrust-to-weight ratio of 7, but emphasizing its comprehensive advantages.

The Shenyang factory has expanded its production line, producing thousands of WS-15 engines. Although Musk's DOGE hasn't directly targeted engines, it has indirectly promoted transparency. In March, a congressional hearing discussed military costs, possibly affecting Pratt & Whitney contracts.

Thrust-to-weight ratio is not the only indicator. The F119 has a pressure ratio of 26:1 and a turbine inlet temperature of 1649 degrees Celsius, showing strong heat resistance. The F135 is even higher, with a pressure ratio of 28:1 and a turbine inlet temperature of 1980 degrees Celsius, but it's heavier, suitable for the F-35's vertical takeoff variant. The WS-15 reportedly has a pressure ratio above 25:1, with single-crystal alloy blades learned from Russian technology, now produced domestically.

In actual flights, the thrust-to-weight ratio affects climb and turn, but stealth and electronic warfare determine the outcome. The U.S. F-35 proved its strength in low-altitude penetration in Israeli operations, but thermal management and lifespan are its shortcomings. The Chinese J-20, operating in the East China Sea, benefits from the WS-15 for stable supersonic cruise, reducing reliance on AL-31.

Original article: https://www.toutiao.com/article/7566977033683665444/

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