China’s new J-35

As part of our series on fifth gen fighter aircraft, earlier in 2024 we looked at the Shenyang FC-31, or J-31. Originally a competitor to the J-20, the concept lost out, becoming a privately funded venture. Emerging as a working prototype in 2012, and publicly unveiled in 2014, the J-31 nonetheless slowly faded into relative obscurity.

While there were some indications that the aircraft may have continued experimentally, many presumed the project was essentially dead. However, in our video we speculated that – based on our limited information – Shenyang was developing the aircraft into land based and naval variants, and possibly a third twin-seat configuration. Chinese aviation enthusiasts suggested the name had changed to J-35. And now, in November 2024, at the Zhuhai Air show in China, the new J-35A made an impressive debut.

In this video we are going to break down everything we know so far about the new design, from rumours and observations, to officially released information. As with our other videos discussing PLA aircraft, there may be more speculation than officially released information, but that’s the nature of things when discussing contemporary Chinese military aircraft.

Nevertheless – let’s dive in!

BACKGROUND

The J-31 concept has a long history which led to the recent debut of the J-35. You can review that history in our J-31 video. In essence, the aircraft became a private venture of Shenyang, and in recent years there was information confirming government intervention— suggesting that the J-31 design was going to be utilised in some way by the Chinese military.

The first big development since our J-31 video came in July 2024, was a press release showing the PLAN unveiling mock-up images of a new carrier-based aircraft. This was publicly circulated in China as the J-31B, a carrier-based derivative of the original J-31 concept, although there might be more to this story, and we will get to that later.

Then, in August, Pakistani news outlets reported that their pilots had begun training on the FC-31, with the government considering purchasing the aircraft, if it hasn’t already. Pakistani sources still refer to the aircraft as the FC-31, although it remains unclear which specific model of the aircraft they are referring to.

In October, the PLAAFPLAAF (People's Liberation Army Air Force) – The aerial warfare service branch of the People's Liberation Army and the official air force of the Peopl... More unexpectedly announced that a new aircraft was now in military service; this was the J-35A, a land based multirole aircraft developed from the FC-31.

Finally, at the recent Zhuhai Air Show, the new aircraft made a surprise debut. From what we can see, this is a revamped airframe, something between the J-20 and F-35 from outward appearances, and likely not in its final form.

VARIANTS

Let’s do a brief survey of the claimed variants of the aircraft currently being developed. Keep in mind, we still do not have clear evidence of the official designations for some of these aircraft, so we will use the current Western designations as we talk about these variants.

The FC-31

To begin with, the first variant to come to light publicly was the working prototype, commonly referred to as the FC-31 Gyrfalcon. Supposedly taking its maiden flight in 2012, it was publicly displayed in 2014. This prototype was evidently far from perfect; its engines were somewhat archaic, and its performance seemed to hinge upon its use of afterburnerAfterburner (Reheat): An additional combustion component utilized in many supersonic military jet engines to provide a significant, temporary increase... More – with several commentators suggesting this was the result of aerodynamic inconsistencies.

The J-35A

The first production variant is the J-35A. This is the aircraft seen at Zhuhai in November 2024. Unlike the initial concept, this new aircraft appears far sleeker, notably ditching the triangular vertical stabilisers for a swept back design. It also features a new canopy, what appears to be slightly smaller wings, and variety of new systems to improve stealth – which will be discussed later. Suffice it to say, the A model is considerably different from the prototype, both in outward appearance and onboard systems.

The J-31B

The B variant is presumed to be the carrier aircraft shown off by the PLAN in their media releases from earlier in the year. This version, according to Chinese sources, is a significant upgrade from the current J-15s serving the Chinese Navy and will be rolled out on China’s third aircraft carrier – the Fujian. In contrast to the J-35A, the 31B is larger, with more robust landing gear for carrier use, and the ability to launch using either ramp or catapult assistance. It seems to feature a slightly different tailplane and vertical stabiliser to the J-35A. Some have claimed that the J-31B may actually be a land-based variant for the Air Force designed to fill a similar role to the Su-30 or J-16, although from outward appearances we don’t think so; the landing gear alone is a good indication that carrier operations will be part of its tasking.

The other notable change is regarding internal weapons stores. Unlike other variants, the 31B has two side weapons bays— one on either side of the fuselage – presumably allowing for at least two extra missiles of some sort. Beyond this, it retains its main bay, which features roughly six hard points and six hardpoints on the wings. Given its larger size it may potentially hold more, although it is equally possible that if it is set up for carrier use, it may have less internal space.

The J-31C

We presume there is a third version based on other available images. For the sake of clarity in this video, we will refer to this simply as the J-31C, although no designation currently exists. This aircraft appears to be a naval version, smaller than the J-31B, although different from the land-based variant. It is highly possible that this was merely an earlier iteration of the J-31B, perhaps a concept using an existing airframe. Notably, in images circulating online, it features reinforced landing gear – suggesting carrier use. In some mock-ups from China it features fixed wings and tailplane, yet in others they are folding. The main differentiating factor seems to be that unlike the J-31B, this seemingly smaller aircraft lacks the two side weapons bays.

We believe this third variant was likely a conceptual experiment deviating from the FC-31 as a testbed for the J-31B. Although, if another naval variant is announced, it wouldn’t be surprising.

The J-35S

Finally, enthusiasts in China seem convinced that there will be a further variant which may be set up in a twin seat configuration, which they refer to as the J-35S. We have talked about this concept of moving back towards twin seat configurations for certain aircraft. There is a good reason for this; in a multirole setting two people in the cockpit are better than one, sharing the workload and allowing for better focus on specific tasks. What will make twin seat configurations even more crucial will be the increased adoption of drone technology, either loyal wingman configured smart aircraft which can be networked or given commands, or more conventional autonomous drones which can also be slaved to a manned aircraft.

So a twin seat J-35 under development is highly possible, and would conform to current PLAAFPLAAF (People's Liberation Army Air Force) – The aerial warfare service branch of the People's Liberation Army and the official air force of the Peopl... More doctrine regarding new fighters.

ARMAMENT

What do we know about armament? The original FC-31 concept was claimed to have a stores capacity of 18,000 pounds total. Broken down, 13,000 pounds could be held on the six external hardpoints, whilst 5,000 pounds could be held internally. In total, the original FC-31 had a maximum take-off weight of 55,000 pounds.

From what is being reported, we know that this take-off weight improved dramatically in later concepts, up to 62,000 pounds. While we don’t have official specifications, we can infer that the J-35A would at least match this, if not outperform, whilst the J-31B is almost certain to have a higher maximum weight given its larger size.

In terms of configuration, the J-35A can hold six air-to-air missiles internally, or four larger air-to-ground munitions – be it cruise missiles or bombs. Presumably these can also be set up on the external hard points. It will also carry the latest PLA air-to-air munitions; the PL-15 for long range standoff, the PL-10 for within visual range, and the hypersonic PL-21— which is something akin to Russia’s R-37.

PERFORMANCE

In terms of overall performance, the claimed combat range of the aircraft is around 1,200 kilometres, with a top speed somewhere around Mach 1.8, and service ceiling just over 50,000 feet.

The airframe looks like it has followed similar design principles to other fifth gen fighters. However, the J-35 does seem to borrow inspiration from the Flanker, particularly along the fuselage. This was noted by Chinese designers, who highlighted the aerodynamic advantages of retaining the distinct bubble behind the cockpit which is often found on Flankers; a set of studies claim that this shape of the fuselage can lower drag, thus improve efficiency.

We’ve no reason to doubt this is true, however we can presume Lockheed would have considered this dynamic as well, when designing the F-22, but they managed to find a way of lowering drag while having a steeper subsidence around the cockpit, giving better rear visibility. The same can also be said about the J-20.

The J-35 is also a particularly slim design, especially when compared to its chief rival – the F-35. We can only speculate that this slimmer shape will impact radar cross section. In fact, this is one of the primary benefits of the aircraft put forward by the designers; supposedly the shaping of the airframe, combined with diverterless supersonic inlets, S-ducts to hide fan blades, and sawtooth edges provide a massively lowered radar cross section. This is said to be aided by a mixture of composite materials with radar absorbent materials baked in, followed by radar absorbent coating applied afterwards. The stealth attributes are complimented by a Luneberg Lens under the fuselage for radar reflection.

The aircraft has a twin-engine configuration supposedly powered by the WS-19. This engine has been under development since the early years of the J-35 project and has seen major overhauls in the years since.

The Chinese are now able to produce powerful jet engines but may still struggle with longevity and consistent reliability. In the past this may have been due to very slight inconsistencies in machining when producing balanced components, leading to slight centrifugal imbalances, initially unnoticeable due to their minuteness, but over time amplified, eventually leading to failure. This was also seen in consumer components, notably car turbochargers which require a similar level of precision machining and centrifugal balance, and even certain computer parts like fans.

Today however, these issues appear less and less common, and even consumer goods with continual strain on centrifugal parts – like drones – seem to operate very reliably. We assume this reliability is also found in Chinese jet engine manufacturing, and why China is now willing to use native engines over Russian built ones. At the recent Zhuhai demonstration, the new WS-19s were supposedly installed— previously the J-31 was using the WS-21, based on the Russian RD-93. Unlike earlier flights, the aircraft today produces far less smoke, and is said to be capable of producing 26,000 pounds of thrust per turbine wet.

On a related note, it remains a mystery why the WS-19 – if these were the engines used during the demo – produce the level of smoke they do in the videos we’ve seen. While smoke is less of an issue today due to beyond visual rangeBVR (Beyond Visual Range): In aerial warfare, engagements or combat operations that occur at distances where opposing aircraft cannot visually identif... More combat, the only real concern is efficiency. All fifth gen fighters produce smoke to some extent, but clearly visible trails are usually because of incomplete combustion. This can happen at lower throttle ranges, when doing throttle bursts, or when dropping out of afterburnerAfterburner (Reheat): An additional combustion component utilized in many supersonic military jet engines to provide a significant, temporary increase... More. Interestingly, at the recent Zhuhai display, as well as in the filmed rehearsal for the air show, the opposite seems to occur; with the J-35 producing more noticeable smoke as it reached military power before afterburnerAfterburner (Reheat): An additional combustion component utilized in many supersonic military jet engines to provide a significant, temporary increase... More. However, since we do not have all the details, we won’t try to speculate any further.

Some reports indicate that the PLAN is still waiting for a finished variant of the WS-19 before mass producing the J-31B, suggesting that whatever is in the current demo aircraft are not the final production engines.

With agility and in-flight characteristics, the initial 2014 flight demonstrated particularly poor turning ability, with the pilot relying on afterburnerAfterburner (Reheat): An additional combustion component utilized in many supersonic military jet engines to provide a significant, temporary increase... More to hold the nose up. Certainly, this would have had to have been addressed before the military would even consider purchasing, even though the recent air show flyby didn’t give us enough to fully gauge improved flight characteristics.

The J-20 has demonstrated good agility, while the J-35s main competitor – the F-35 – is now at a point where its air show demonstrations are very impressive, showing off impressive turn rates, acceleration, and even low speed performance – which is not even a primary focus for the design. Thus, until a proper demonstration of J-35 agility is provided, international customers are likely to favour the proven performance of the F-35.

COMPETING WITH WESTERN DESIGNS

Since its outset, those who have been associated with the FC-31 program have spoken about it as either a competitor or an alternative to the F-35, with a focus on export customers. And this does indeed seem to be the goal.

A recent article from China Daily sheds some light on this. In the article, PLA senior researcher Wang Mingzhi states that the J-35A will work alongside the J-20 as the backbone of their Air Force, with an emphasis on stealth capability. He said that while the J-20 will do the heavy lifting in terms of air superiority, the J-35A will fulfil multirole tasking, including combat air patrol, and precision air-to-ground and air-to-sea missions.

Two further points in the article are also telling. A PLAAFPLAAF (People's Liberation Army Air Force) – The aerial warfare service branch of the People's Liberation Army and the official air force of the Peopl... More veteran pilot – Fu Qianshao – said that he believed the J-20 was a great aircraft, but very costly. He goes on to say that the J-35 seems to balance good performance, with lower procurement and operating costs, explicitly stating that the J-35 has what he calls “lower air drag and outstanding stealth technology”.

The article ends with some words from Wang Yanan – another aerospace journalist in China – who believes that the J-35 is technologically more advanced than the J-20, with newer manufacturing techniques, newer onboard systems, and the ability for easier upgrades of avionics and electronic systems if needed.

The interplay between the J-20 and J-35 is reminiscent of the situation in the US and Russia. In the US, the F-35 is marketed as a more modern multirole export aircraft, which compliments the older but supposedly more capable F-22 tasked with air superiority. Likewise, Russia for a while was marketing its Su-75 Checkmate as a multirole export aircraft with the latest systems, while internally it would cooperate with the older but again more capable Su-57.

Understandably the most cutting-edge military technology is often prohibited from export. It follows that the J-35 – at least the Alpha variant – will not be the most cutting-edge fighter in China’s arsenal—evidenced by its lower cost, willingness to export, and statements from PLA experts. The J-20, however, remains the PLAAFs preeminent fighter, while the J-35 will be the equivalent to the F-35 – complementary in the arsenal and also exportable.

The parallel with the F-35 is substantiated by other statements coming out of China. Wang Yongqing – who works at Shenyang – says that a focus for the platform will be “network integration and intelligence capabilities”, as well as “excellent handling and user-friendly human machine interaction”. This infers the aircraft will adopt a type of sensor fusion system similar to that which has been sold with the F-35.

The shorter range of the aircraft is also important to consider. While the F-35 and F-22 also have shorter ranges, Chinese aircraft are at a far greater disadvantage. This is because China does not yet operate a wide array of air-to-air refuelling aircraft necessary to support a huge fleet of shorter-range fighters. In contrast, the US has almost 600 specialised refuelling aircraft, along with several multirole aircraft capable of buddy refuelling in flight.

The J-35s engines are also not on par with the F135 found in the F-35 – which remains the most powerful afterburning engine widely in use today.

The J-35 will however be slightly lighter and reach a slightly higher maximum speed of Mach 1.8.

Perhaps the most telling piece of information which suggests that the J-35 may be able to compete with the F-35 in some capacity comes from the infamous hacking scandal from a decade ago. Beginning around 2008, a Chinese national – supposedly with the help of PLA hackers – managed to infiltrate various US military contractor systems. From there, they copied over 600,000 documents, primarily relating to the Joint Strike Fighter program, and a few relating to F-22 systems. Whether this benefited the J-35 program is a matter of dispute, although it is possible.

When it comes to costs parameters, the high-low mix strategy China seems to be going for is not the case with the F-22 and F-35 relationship. The F-35 is not necessarily intended to be a low budget compliment to the Raptor. In the past a high-low mix was a strategy with fourth generation aircraft but isn’t generally a strategy for other Air Forces today.

When considering onboard systems, the J-35 is said to be using the KLJ-7A AESAAESA (Active Electronically Scanned Array) Radar: An advanced radar system that uses an array of numerous small solid-state transmit/receive modules t... More radar system, complimenting the KLJ-5 found in the J-20. We don’t know if this is true, although it would make sense given it is an export aircraft. As mentioned in our J-16 video, the KLJ-7 has a synthetic aperture resolution to just under 1 meter. In contrast, the F-35 uses the AN/APG-81 – claimed to be the most advanced AESAAESA (Active Electronically Scanned Array) Radar: An advanced radar system that uses an array of numerous small solid-state transmit/receive modules t... More radar currently fitted to any aircraft – with great air-to-air performance. Based on publicly available images, we presumed that the APG-81 has a synthetic aperture clarity down to at least 20 centimetres, rendering in fine details tire tracks and small shadows. The F-35 will eventually be upgraded to the AN/APG-85 system as part of a Block IV upgrade program. We doubt the KLJ-7 – a budget export radar – can come close to matching this.

In terms of optical systems, the F-35 uses the AN/AAQ-40 EOTS, which provides laser targeting, long range IRST, and FLIRForward-Looking Infrared (FLIR) is an airborne or vehicle-mounted thermal imaging system that detects infrared radiation (heat) emitted by objects and... More. Several other systems are also linked, ten radar antennas embedded in the wing and tail give all aspect RWR capabilities, six infrared sensors give all aspect target tracking and missile launch warning cues. This is also fused to produce a multispectral image, which can be used to then geolocate threats to either defend from or attack. This suite also includes sensor fusion which combines a variety of datalink systems and radio frequencies into a single understandable readout for the pilot, although the full extent of this is not publicly available. Finally, as part of its sensor fusion platform, the F-35 crucially features a situational awareness system (SAIRST), which gives the spherical imagery projected onto the helmet display, which can be cycled between night vision, infrared, and presumably standard spectrum imagery.

In contrast, the J-35 seems to use the EOTS-86 MAWS, which is also used on the J-20. Much less is known about this system. If it is based on Russian EO systems, then it is likely good. We can only presume that this system attempts to replicate similar capabilities to that of the EOTS system in the F-35. J-35 pilots will supposedly have similar data displayed through sensor fusion onto either the HUDHUD (Head-Up Display): A transparent display system that presents critical information directly in a user's line of sight, eliminating the need to loo... More, or onto a helmet mounted display based on the BAEA British multinational defense, security, and aerospace company headquartered in London and one of the world's largest defense contractors. Formed in... More Striker system. But again, very little is known about this system, and most of the information online comes from rumours and civilian analysis rather than from the developers themselves, so we cannot really say for sure how it measures up to the suite on the F-35.

To summarise, we do not believe the J-35 in its current form can outcompete the F-35, especially when it comes to radar performance or fusion sensors. However, if China continues to make technological leaps, it has the possibility to be a very capable adversary to anything in the west.

CONCLUSION AND FUTURE

Chinas new Fujian carrier is a big deal in the country, a technological leap forward from the older ramp-based designs of the past. We can assume that the J-31B (if it is indeed the naval variant) will see itself on the Fujian.

The WS-19 is probably still in last-stage development, despite announcements of the J-35A’s entrance into service. We believe this, not only because of the smoking issues during demonstrations, but more importantly because the Navy are waiting for these final engines to be delivered. It is not unreasonable to assume that the ground-based variant is running with an early variant of the engine, and that the final production engine will be installed once completed. We think it is telling that the Navy is waiting; consider that ground-based aircraft can use experimental engines with lower risk than naval fighters which are launching from catapults, operating over oceans, and having to land on very narrow recovery paths, with little margin for error. One test aircraft was supposedly launched from the Liaoning, however we don’t know if testing on the Fujian, and its catapult system, has begun.

A twin seat variant is probably on the cards, and it should come as no surprise if announced. This so-called J-35S makes sense given the marketing of the aircraft; it is a multirole aircraft with air-to-air, air-to-ground, air-to-sea, networking and intelligence, and drone control all being admitted by those in China as features or goals of the platform. If the J-20 is receiving a twin seat variant, it is likely the same will happen with the J-35 at some point.

It will be interesting to see what happens with the marketing campaign. While we will likely never get the full specifications of the aircraft – just as with the F-35 – we may at least see a little more regarding its capabilities, in a bid to sell the aircraft on the international marketplace.

The J-35 platform represents an interesting development for the PLA Air Force and Navy. We believe that if any aircraft is going to emerge from China which seeks to directly outperform the F-35 or Su-57, it will be the more expensive, more advanced J-20, not the J-35. Nevertheless, the J-35 promises the latest avionics and sensor fusion systems in a multirole package, without a huge price tag. This makes it potentially a great aircraft to integrate into a fleet— in this way we think it is much more comparable to South Korea’s KF-21, which puts less emphasis on dominating the skies, but more on interlinking with other aircraft and assets in the battle space, controlling drones, switching between multirole tasking, and so forth. But anything is possible, and as we always say – only time will tell.