Chengdu J-20 5th Generation Aircraft News & Discussions

[Beijingwalker]

The first test flight of a Chinese Air Force J-20A stealth fighter equipped with the new WS-15 engine is recorded​

December 29, 2025

Following the recent release of images on social media, the first test flight involving a Chinese Air Force J-20A stealth fighter equipped with the new WS-15 engine has been recorded. These engines are intended to replace the WS-10 models previously fitted to this variant of the aircraft. The images in question appear more than two years after official sources stated that the engine had already entered production, which—if sustained over time—would represent a significant leap in capability for the platform and a major milestone for the Chinese aerospace industry.

It is worth recalling that the development of the WS-15 engine dates back to the 1990s, when it was pursued in parallel with the design of the J-20 fighters themselves, which today form the backbone of China’s stealth airpower. This effort has repeatedly been described as the “Achilles’ heel” of the country’s aerospace industry, as various technical obstacles and resulting delays initially led to the integration of Russian Saturn AL-31 engines on the platform, followed later by the adoption of the WS-10 during serial production. However, the WS-10 was originally designed for the J-10 fighters of the Chinese Air Force and fell short of the performance requirements desired for a stealth fighter of this class.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

This point is particularly relevant given that, although many technical aspects of the WS-15 remain undisclosed, the primary objective behind its development has been to match the performance of the F119 engines used on the U.S. F-22, widely regarded as one of the most capable air superiority fighters in the world. In this context, the WS-10 proved insufficient in terms of speed, acceleration, and supercruise capability, as well as in its ability to generate enough electrical power to support future systems planned for integration on the J-20.

By way of illustration, preliminary data on WS-15 prototypes indicated the ability to generate up to 36,000 pounds of thrust, with projected targets reaching 40,000 pounds. When compared to the WS-10—rated at around 32,000 pounds of thrust—the improvement is evident. The aforementioned F119 engines, according to U.S. manufacturer Pratt & Whitney, deliver approximately 35,000 pounds of thrust.

Beyond the purely technical aspects, the progress reflected in this recorded test flight also represents a further step toward consolidating indigenous industrial capabilities and achieving greater strategic autonomy in the future. As noted by various analysts, the development of high-performance jet engines had until now been one of the advantages that the West still maintained over Beijing in the medium term, underscoring the rapid pace of advancement achieved by the Chinese industry.

Finally, it is equally relevant to note that the integration of the new WS-15 engines is not the only upgrade undertaken to enhance the J-20’s combat capabilities. Among other known changes are a redesigned radome, increased internal fuselage volume—potentially indicating greater fuel capacity or space for new avionics systems—and a cockpit positioned higher, all of which have been observed in previous imagery.

 

[Beijingwalker]

China’s J-20A Stealth Fighter Conducts First Test Flight with New WS-15 Engine​

By News Desk
Last updated: December 29, 2025

In a significant advancement for China’s aerospace capabilities, recent images shared on social media indicate that the Chinese Air Force’s J-20A stealth fighter has successfully completed its first test flight featuring the new WS-15 engine.

This development marks a pivotal transition from the previously used WS-10 engines, heralding a potential escalation in the performance and capabilities of this crucial aircraft variant.

Observations of this test flight emerge over two years after official announcements confirmed that WS-15 engines had begun production, symbolizing both a technological breakthrough and a key milestone for China’s defense industry.

The WS-15 engine’s development began in the 1990s, concurrently with the design efforts of the J-20 fighters—now an essential component of China’s stealth airpower. Historically, the evolution of this engine has faced challenges, often being referred to as the “Achilles’ heel” of China’s aerospace sector. Initial setbacks forced the J-20 to rely on Russian Saturn AL-31 engines, later upgrading to the WS-10 during mass production. However, the WS-10 was primarily crafted for the J-10 fighters and lacked the necessary performance specifications to fulfill the demanding requirements of a modern stealth fighter.

Notably, the WS-15’s design aims to rival the capabilities of the F119 engines found in the U.S. F-22, considered one of the most formidable air superiority fighters globally. Previous assessments indicated that the WS-10 did not meet the necessary benchmarks in terms of speed, acceleration, or supercruise ability, nor could it produce adequate electrical power for advanced systems intended for future implementation on the J-20.

Preliminary data regarding WS-15 prototypes suggested thrust capabilities reaching up to 36,000 pounds, with aspirations to achieve 40,000 pounds. In contrast, the WS-10 offers around 32,000 pounds of thrust, highlighting the substantial improvements that the WS-15 engine could bring to the fighter’s overall performance. For perspective, the F119 engines are reported to generate approximately 35,000 pounds of thrust.

Beyond the technical achievements represented by this test flight, the growing capabilities signal a concerted effort by China to bolster its indigenous industrial prowess and assert greater strategic autonomy in aerospace technology. Analysts emphasize that the development of high-performance jet engines had long been an area where Western nations maintained a competitive edge over China, underscoring the rapid progress now emerging from Chinese manufacturing and engineering sectors.

In addition to integrating the WS-15 engines, several other upgrades have been reported to enhance the J-20’s combat effectiveness. These improvements include a redesigned radome, increased internal fuselage volume—which could allow for greater fuel capacity or accommodate new avionics systems—and a repositioned cockpit that is situated higher, as evidenced in earlier imagery.

This combination of advancements positions the J-20A as a more formidable contender in modern air combat, further solidifying China’s commitment to advancing its aerospace capabilities on the global stage.

China's J-20A Stealth Fighter Conducts First Test Flight with New WS-15 Engine - SSBCrack News

In a significant advancement for China's aerospace capabilities, recent images shared on social media indicate that the Chinese Air Force's J-20A stealth

news.ssbcrack.com

 

[Beijingwalker]

WS-15 prototypes indicated the ability to generate up to 36,000 pounds of thrust, with projected targets reaching 40,000 pounds.
F119 engines used on the U.S. F-22, according to U.S. manufacturer Pratt & Whitney, deliver approximately 35,000 pounds of thrust.

That's indeed a great leapforward for the Chinese jet engines ! Never expected that Chinese jet engine and chipmaking industries can catch up this fast, just coupls of years spent.

 

[Ali_Baba]

That's indeed a great leapforward for the Chinese jet engines ! Never expected that Chinese jet engine and chipmaking industries can catch up this fast, just coupls of years spent.

Yes - but what is teh service life, fuel efficiency and MTBO of the chinese engine that makes 36k of thrust vs a US one that makes 35k of thrust.

My money is still on the US engine having at least 2-3x the service life, 1/4 of the MTBO requirements and better fuel efficiency.

If you have evidence that China has caught up in "all metrics" and not just on thrust, I would love to see it.

 

[Beijingwalker]

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[Beijingwalker]

 

[The SC]

The WS-15 engine officially enters service on J-20A fighters



The new engine is a qualitative technological leap; It provides a huge thrust of up to 18,143 kg, giving the fighter superior maneuverability in close air engagements.

More importantly, the WS-15 engine allows the “Mighty Dragon” fighter to have the advantage of continuous supersonic flight without the need to use afterburners, which places the Chinese fifth-generation fighter program in a narrow club that includes only the most powerful international aircraft, and reduces the technological gap with the West once and for all.



Reports confirmed that the first aircraft from the mass production lines, equipped with this engine, successfully completed its final test flight.

 

[Yasser76]

Yes - but what is teh service life, fuel efficiency and MTBO of the chinese engine that makes 36k of thrust vs a US one that makes 35k of thrust.

My money is still on the US engine having at least 2-3x the service life, 1/4 of the MTBO requirements and better fuel efficiency.

If you have evidence that China has caught up in "all metrics" and not just on thrust, I would love to see it.

Good points, but at the rate they are going I think they will solve fuel and MBTO problem quickly. This pace of development is insane fast.

Read somewhere the MBTO may be almost the same number of hours, will hunt for source

 

[Michael]

Read somewhere the MBTO may be almost the same number of hours, will hunt for source

You will find almost no accurate information in public media. The PLA and Chinese defense companies will not release this information publicly.

But, there is one direction you can explore.

The PAF operates both the F-16 (with American engines) and the J-10CE (with Chinese engines).
If you have reliable sources, you can try to find answers in this area.

 

[Yasser76]

You will find almost no accurate information in public media. The PLA and Chinese defense companies will not release this information publicly.

But, there is one direction you can explore.

The PAF operates both the F-16 (with American engines) and the J-10CE (with Chinese engines).
If you have reliable sources, you can try to find answers in this area.

Not claiming the sources are 100% reliable, just what I read. For a very good reason nothing is 100% reliable when it comes to high end military equipment.

 

[Michael]

Not claiming the sources are 100% reliable, just what I read. For a very good reason nothing is 100% reliable when it comes to high end military equipment.

What I mean is:
1. The Chinese military never releases detailed specifications of its weapons and equipment.
2. Chinese defense companies also never release detailed specifications of the versions of weapons and equipment used by the Chinese military. They occasionally release general specifications for export versions, but these specifications are questionable.
3. Chinese official news media and professional academic papers usually use vague language rather than precise descriptions when discussing these parameters.
4. The so-called specifications found on social media are mostly based on speculation and have no reliable value.

============================================================
In real life, I have some friends who work in the field of military aircraft engines. When we talk, we avoid discussing technical details. They are subject to very strict confidentiality regulations.
============================================================

The PAF's confidentiality rules in these areas are not as strict as those in China. They may disclose some information when appropriate.

 

[Yasser76]

What I mean is:
1. The Chinese military never releases detailed specifications of its weapons and equipment.
2. Chinese defense companies also never release detailed specifications of the versions of weapons and equipment used by the Chinese military. They occasionally release general specifications for export versions, but these specifications are questionable.
3. Chinese official news media and professional academic papers usually use vague language rather than precise descriptions when discussing these parameters.
4. The so-called specifications found on social media are mostly based on speculation and have no reliable value.

============================================================
In real life, I have some friends who work in the field of military aircraft engines. When we talk, we avoid discussing technical details. They are subject to very strict confidentiality regulations.
============================================================

The PAF's confidentiality rules in these areas are not as strict as those in China. They may disclose some information when appropriate.

I understood what you meant. Also, please do not pretend you know what PAF confidentiality rules are

 

[Michael]

Also, please do not pretend you know what PAF confidentiality rules are

You seem to think there's bias here? I am not subjectively biased.

The PAF has disclosed a lot of information in public sources, such as the parameters of the J-10CE. But you won't find any news of the PLAAF publicly disclosing the parameters of the J-10C.

There is no bias here.

In fact, we also believe that the PLA's security measures are too strict. On Chinese social media, we often see complaints from military enthusiasts. We would prefer the PLA to release more information.
Fortunately, the PLA is much more open now than before. They have started to change. However, their pace of openness is far slower than what military enthusiasts expect.

To some extent, we hope the PLA can be more open, like other militaries.

 

[Shui]

You seem to think there's bias here? I am not subjectively biased.

The PAF has disclosed a lot of information in public sources, such as the parameters of the J-10CE. But you won't find any news of the PLAAF publicly disclosing the parameters of the J-10C.

There is no bias here.

In fact, we also believe that the PLA's security measures are too strict. On Chinese social media, we often see complaints from military enthusiasts. We would prefer the PLA to release more information.
Fortunately, the PLA is much more open now than before. They have started to change. However, their pace of openness is far slower than what military enthusiasts expect.

To some extent, we hope the PLA can be more open, like other militaries.

I would rather like to have suprises from time to time instead of like our neighbor Indian, CCS approval, a bunch of meeting, introduced timeline.

 

[Ali_Baba]

You will find almost no accurate information in public media. The PLA and Chinese defense companies will not release this information publicly.

But, there is one direction you can explore.

The PAF operates both the F-16 (with American engines) and the J-10CE (with Chinese engines).
If you have reliable sources, you can try to find answers in this area.

The PAF has historically operated very poor quality products from a maintenance perspective because of military need, eg A5 Fantan series were considered to be a maintenance nightmare, so we can't assume a platform meets a maintenance quality threshold just because the PAF has inducted a platform.