Shenyang / Chengdu "6th Gen" Aircraft - News and Analysis

[snne]

rumor mill hints that it may be a production-representative prototype...

An overall solid analysis of the project's current status in light of recent speculations:

 

[Scott Kenny]

Knowing that Chinese doesn't like the number 4 (sounds like death), I'm thinking use airframe #4 as the test-to-destruction airframe. Because you're going to break it anyways.

 

[SUPER=BUG]

Ah, actually most Chinese people don’t really care about how the number 4 sounds, after all, there are many characters in Chinese that share the same pronunciation. Most people just see it as an ordinary number without any particular meaning—neither liking it nor disliking it. Of course, you know, it’s very hard for everyone to hold the same view, so naturally there are always people who dislike this number from all sorts of strange perspectives. Conversely, there are also people who like it in some other weird ways; for example, from a musical point of view, 4 actually seems pretty okay. Among China’s huge population of 1.4 billion, any opinion is bound to find its audience.

Back to the topic, this J36 picture is from a video. The details might not be entirely accurate.

 

[Deino]

Ah, actually most Chinese people don’t really care about how the number 4 sounds, after all, there are many characters in Chinese that share the same pronunciation. Most people just see it as an ordinary number without any particular meaning—neither liking it nor disliking it. Of course, you know, it’s very hard for everyone to hold the same view, so naturally there are always people who dislike this number from all sorts of strange perspectives. Conversely, there are also people who like it in some other weird ways; for example, from a musical point of view, 4 actually seems pretty okay. Among China’s huge population of 1.4 billion, any opinion is bound to find its audience.

Back to the topic, this J36 picture is from a video. The details might not be entirely accurate.

You mean this image?

 

[John Thompson]

1st post

 

[Scott Kenny]

1st post

Welcome!

I still think the better comparison is versus the F-111B (with the short nose), but no point rehashing that argument.

 

[flateric]

1st post

What the sense of comparison [of Paralay's J-36 drawing] to Hustler?

 

[Scott Kenny]

What the sense of comparison [of Paralay's J-36 drawing] to Hustler?

Seems fairly obvious to me, size comparison.

I certainly need to see things in pictures, raw numbers just don't let me picture a size.

 

[Sferrin]

What the sense of comparison [of Paralay's J-36 drawing] to Hustler?

Seriously?

 

[tico]

From a military insider blogger who shared military revelations with cartoon art, the aircraft still retains the 2D thrust vectoring nozzle used after the 2nd prototype. The blue exhaust plume seams to indicate the engine has been switched from WS-10 to WS-15.

 

[Rumil]

From a military insider blogger who shared military revelations with cartoon art, the aircraft still retains the 2D thrust vectoring nozzle used after the 2nd prototype. The blue exhaust plume seams to indicate the engine has been switched from WS-10 to WS-15.

Few other points from the insider

4 prototypes exist, 3rd is static test specimen.
They skipped 36014 so 36015 is essentially the 4th (from last week) with optimized WS-15.
Next airframe will be an lrip unit, expected by Q1/2027.

H20 is still in development but the priority level is not high like J-36.

 

[EmoBirb]

XAC enthusiasts keep taking L's

I'm still curious as to why only the earliest airframe had what one may consider a superior nozzle arrangement.

 

[tico]

I believe CAC may never have finalized the design of the first prototype, which serves only as a transitional testbed. The evidence is that in an article on engine technology authored by Wang Haifeng of the J-36 program several years ago, he mentioned mechanical thrust vectoring and fluidic thrust vectoring, yet made no mention whatsoever of YF-23-style exhaust nozzles.
https://mp.weixin.qq.com/s?__biz=Mz...ecaf15be635c44154a596135d989c6b97043&scene=27

More intriguingly, the latest sixth generation fighter concepts from the designers
of the YF-23 darold Cummings also adopt thrust vectoring, instead of the nozzle design used on the YF-23. One reason, as noted in the article, is that thrust vectoring is more critical for flight control of tailless aircraft. Another possible reason is that in terms of development potential, the YF-23’s nozzle does not possess the stealth advantage over vectoring nozzles that is widely assumed.

 

[Sferrin]

One reason, as noted in the article, is that thrust vectoring is more critical for flight control of tailless aircraft. Another possible reason is that in terms of development potential, the YF-23’s nozzle does not possess the stealth advantage over vectoring nozzles that is widely assumed.

Or, more likely, they found a way to get TVC without the big hit. Else they decided the higher RCS was worth it. See F-22/F-23. Different decisions to reach the same set of requirements.

 

[Brett Davidson]

XAC enthusiasts keep taking L's

I'm still curious as to why only the earliest airframe had what one may consider a superior nozzle arrangement.

My guess is heat management and a preference for the capabilities of thrust vectoring. Three hot plumes running through troughs, even at the rear of the plane, are likely to convey a lot of heat to the airframe - which will reradiate it for the benefit of heat seeking missiles. It might be bearable for a high-bypass subsonic aircraft (B-2, B-21) but not for something supersonic.

Northrop's YF-23 shows how hard they tried to keep it under control with tiles. Nobody in the West I can immediately think of has tried it since.

 

[TangJu]

May be the nozzle design patent for the first prototype.

An aero-engine nozzle with adjustable detectability

1. With the continuous advancement of aerospace detection technology, detectability management of aircraft in complex airspace environments has become a key focus of frontier research. The nozzle system of an aero-engine, as a critical passage for discharging high-temperature combustion gases, produces significant electromagnetic scattering characteristics and infrared radiation signatures, and is one of the main factors affecting the aft signature characteristics of an aircraft. Therefore, developing advanced nozzle technologies to effectively manage these signature characteristics is of great significance for improving the overall performance indices of aircraft.

2. At present, the design of aero-engine nozzles faces an inherent contradiction between high-performance aerodynamic requirements and low-detectability requirements. High-performance aero-engines pursue a high thrust-to-weight ratio and high efficiency, which require the nozzle to have a smooth flow path and optimized area-adjustment capability under full-power, i.e., afterburning, conditions so as to maximize thrust output. However, from the perspective of low detectability, it is necessary to optimize signature characteristics by means such as “geometric shaping” and “thermal management,” which often requires changing or even constraining the shape of the flow path, thereby possibly disturbing airflow and causing performance losses. How to achieve low detectability without sacrificing core aerodynamic performance is an extremely challenging design problem.

3. Among existing technical solutions, there are certain limitations in the approaches for achieving low detectability of nozzles. The first is conventional mechanically adjustable nozzle technology. The design core of such nozzles lies in changing the throat area through movement of movable adjusting flaps, so as to meet the aerodynamic requirements of the engine under different operating conditions. However, the original purpose of their adjustment mode is entirely to serve aerodynamic performance, and the range of configuration variation does not take low detectability as a design objective. Therefore, their structure cannot effectively shield upstream high-temperature components, and has limited potential in reducing electromagnetic and infrared signature characteristics.

4. The second is fixed special-configuration nozzle technology, such as nozzles employing curved flow paths or non-axisymmetric cross sections. By virtue of their inherent geometry, such designs can physically shield internal high-temperature regions by the nozzle walls, thereby optimizing signature characteristics to a certain extent. However, such nozzles are generally of fixed configuration and lack throat-area adjustment capability. When an aircraft needs to ignite an afterburner to obtain maximum thrust, the fixed and complex flow-path shape restricts exhaust efficiency, resulting in significant thrust-performance losses, and making it difficult to meet the stringent thrust-response requirements of highly maneuverable flight platforms. Therefore, they are commonly used in application scenarios that do not require a wide thrust-variation range.

5. The third is that, in terms of thermal management technology, existing nozzles mostly rely on cold air from an engine bypass duct or airframe bleed air to perform continuous wall cooling. This long-duration and stable cooling mode has a basic effect in maintaining component temperatures and achieving basic infrared signature control. However, when an aircraft faces specific high-demand scenarios requiring abrupt changes in signature characteristics, such as in heavily monitored airspace or when urgent flight-state adjustment is required, the cooling intensity and response speed of the prior art cannot achieve rapid and active suppression of signature characteristics, and there is a bottleneck in improving effectiveness.

6. In summary, the prior art lacks a comprehensive nozzle solution capable of intelligently adapting to multiple flight-mission requirements. In particular, for high-performance afterburning engines, there is an urgent need for an advanced nozzle capable of dynamically adjusting its own configuration and flexibly switching between a “high aerodynamic performance mode” and a “low-detectability mode.” Such a nozzle must not only solve the integrated-design problem of variable geometry and signature control, but also integrate a highly reliable adjustment mechanism, effective sealing, and a multi-stage thermal management system within a compact space, thereby truly achieving synergistic optimization of aerodynamic performance and low detectability, and enhancing the overall technical competitiveness of the aircraft.

Technical Solution

1. To solve the above problems, the present application provides a detectability-adjustable aero-engine nozzle, mainly comprising a rectangular section connected to a circular nozzle outlet through a round-to-square transition section. The rectangular section includes an upper outer cowl, a lower outer cowl, and side walls. An adjusting plate is disposed between the upper outer cowl and the lower outer cowl. The adjusting plate includes a first adjusting flap, a second adjusting flap, and a unilateral expansion section. The first adjusting flap and the second adjusting flap are respectively slidably disposed in track slots of an arcuate throat plate. The other end of the first adjusting flap is hinged to the round-to-square transition section. The other end of the second adjusting flap is hinged to the unilateral expansion section. The other end of the unilateral expansion section is connected to a distal end of the lower outer cowl. The arcuate throat plate is mounted by side shafts in tracks located on the side walls, and is driven by an actuator cylinder to move upward and downward, so as to control a throat clearance between the adjusting plate and the upper outer cowl.

2. A gas accommodation space is formed between the adjusting plate and the lower outer cowl. Gas drawn from an engine bypass duct or an engine nacelle enters the gas accommodation space through a first injection rod. A cooling medium drawn from an ultra-low-temperature cold source enters the gas accommodation space on demand through a second injection rod. Film cooling holes are provided at least on the unilateral expansion section of the adjusting plate, so as to introduce the gas in the gas accommodation space to an inner wall of the rectangular section to form a cooling air film.

3. Preferably, an arcuate surface of the arcuate throat plate has track slots, and two ends of the track slots are provided with tenon grooves for mounting tenons of the first adjusting flap and the second adjusting flap.

4. Preferably, an inner side of the upper outer cowl is further provided with an upper convergent flap configured to contract a vertical spacing of the rectangular section, and an upper divergent flap configured to expand the vertical spacing of the rectangular section. The upper convergent flap and the upper divergent flap are opposite, at a connection portion thereof, to a hinged end between the second adjusting flap and the unilateral expansion section.

5. Preferably, film cooling holes are respectively provided on the second adjusting flap, the upper divergent flap, the side walls, and the arcuate throat plate.

6. Preferably, the ultra-low-temperature cold source is liquid nitrogen.

7. Preferably, in an emergency evasion state, the second injection rod is briefly opened to rapidly cool the nozzle by the cooling medium.

8. Through a deformable nozzle structure, the present application realizes intelligent switching between high aerodynamic performance and low detectability, and innovatively integrates long-duration and short-duration active cooling technologies, ultimately achieving ultra-high-performance comprehensive signature management.

Technical Features

1. A detectability-adjustable aero-engine nozzle, comprising a rectangular section connected to a circular nozzle outlet through a round-to-square transition section (1), wherein the rectangular section comprises an upper outer cowl (10), a lower outer cowl (11), and side walls (9), characterized in that an adjusting plate is disposed between the upper outer cowl (10) and the lower outer cowl (11); the adjusting plate comprises a first adjusting flap (2), a second adjusting flap (5), and a unilateral expansion section (8); the first adjusting flap (2) and the second adjusting flap (5) are respectively slidably disposed in track slots of an arcuate throat plate (3); the other end of the first adjusting flap (2) is hinged to the round-to-square transition section (1); the other end of the second adjusting flap (5) is hinged to the unilateral expansion section (8); the other end of the unilateral expansion section (8) is connected to a distal end of the lower outer cowl (11); the arcuate throat plate (3) is mounted by side shafts in tracks (4) located on the side walls (9), and is driven by an actuator cylinder to move upward and downward, so as to control a throat clearance between the adjusting plate and the upper outer cowl (10).

2. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that an arcuate surface of the arcuate throat plate (3) is provided with track slots, and two ends of the track slots are provided with tenon grooves for mounting tenons of the first adjusting flap (2) and the second adjusting flap (5).

3. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that an inner side of the upper outer cowl (10) is further provided with an upper convergent flap (6) configured to contract a vertical spacing of the rectangular section, and an upper divergent flap (7) configured to expand the vertical spacing of the rectangular section; the upper convergent flap (6) and the upper divergent flap (7) are arranged such that a connection portion thereof faces a hinged end between the second adjusting flap (5) and the unilateral expansion section (8).

4. The detectability-adjustable aero-engine nozzle according to claim 3, characterized in that film cooling holes are respectively provided on the second adjusting flap (5), the upper divergent flap (7), the side walls (9), and the arcuate throat plate (3).

5. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that the ultra-low-temperature cold source is liquid nitrogen.

6. The detectability-adjustable aero-engine nozzle according to claim 1, characterized in that, in an emergency evasion state, the second injection rod (15) is briefly opened to rapidly cool the nozzle by a cooling medium.

Technical Summary

The present application belongs to the technical field of aero-engine structural design, and relates to a detectability-adjustable aero-engine nozzle. The core of the nozzle lies in a deformable structure, which mainly comprises a round-to-square transition section, adjusting flaps, an arcuate throat plate, a unilateral expansion section, and an actuating mechanism. The arcuate throat plate is driven by an actuator cylinder to move upward and downward in tracks on the side walls, thereby driving the adjusting flaps to move, so as to intelligently switch the nozzle configuration: upward movement forms a low-detectability mode, in which the unilateral expansion section achieves full shielding; downward movement enables a high-thrust mode. Meanwhile, the nozzle integrates a dual-path cooling system, one path providing long-duration basic cooling, and the other path being capable of briefly injecting an ultra-low-temperature medium for active intensive cooling. The engine of the present application can meet detection-avoidance requirements, as well as requirements for flame propagation and stability in an afterburning state.


Inventors: Wang Dianlei, Liu Taiqiu, Zhao Ming, Cheng Jia, Wu Fei, Zhan Jiazhe
Protected technology user: AECC Shenyang Engine Research Institute
Technology development date:
Technology publication date: April 2, 2026

 

[Tomboy]

My guess is heat management and a preference for the capabilities of thrust vectoring. Three hot plumes running through troughs, even at the rear of the plane, are likely to convey a lot of heat to the airframe - which will reradiate it for the benefit of heat seeking missiles. It might be bearable for a high-bypass subsonic aircraft (B-2, B-21) but not for something supersonic.

Northrop's YF-23 shows how hard they tried to keep it under control with tiles. Nobody in the West I can immediately think of has tried it since.

AFAIK the OG nozzles were also capable of TVC, though it could be that it proved that the advantage over traditional 2D TVC nozzles during actual flight tests may be not enough to justify adding a whole bunch of complexity with flexible hinges and heat treatment and/or that they were on a tight schedule and traditional 2D TVC still met stealth/maneuverability requirements without need for more exotic solutions that may possibly be added in later blocks.

 

[Scott Kenny]

May be the nozzle design patent for the first prototype.
[...]

That is very interesting. But since it was published I doubt that it is being used on the production versions.

Also, per figure 2 you're looking at needing additional radar blockers upstream of the nozzle, there is a straight shot up the tail when the nozzle is fully open.

 

[Schwerter_105]

That is very interesting. But since it was published I doubt that it is being used on the production versions.

Also, per figure 2 you're looking at needing additional radar blockers upstream of the nozzle, there is a straight shot up the tail when the nozzle is fully open.

Published stuff can still be used imo (if not the exact same design then at least quite similar), a few days back I saw a patent on what is almost identical to the GJ11/21 nozzle, it was mainly about external shape but still. Also there was a patent on the tandem two-wheel MLG from CAC that some one found in 2025, quite likely the same or at least very similar to what was used on 36011. I'll have to dig around a bit for them tho

edit: found them

likely GJ11/21 nozzle patent

likely 36011 MLG patent

Unfortunately I haven't seen their patent numbers, just excerpts that others posted

 

[TangJu]

That is very interesting. But since it was published I doubt that it is being used on the production versions.

Also, per figure 2 you're looking at needing additional radar blockers upstream of the nozzle, there is a straight shot up the tail when the nozzle is fully open.

Just a guess, as AECC has repeatedly sought patent protection for the same nozzle configuration through three nearly identical patent applications.

The afterburner integrated with a radar blockers is a separate patent.

 

[Elysium]

I believe CAC may never have finalized the design of the first prototype, which serves only as a transitional testbed. The evidence is that in an article on engine technology authored by Wang Haifeng of the J-36 program several years ago, he mentioned mechanical thrust vectoring and fluidic thrust vectoring, yet made no mention whatsoever of YF-23-style exhaust nozzles.
https://mp.weixin.qq.com/s?__biz=Mz...ecaf15be635c44154a596135d989c6b97043&scene=27

More intriguingly, the latest sixth generation fighter concepts from the designers
of the YF-23 darold Cummings also adopt thrust vectoring, instead of the nozzle design used on the YF-23. One reason, as noted in the article, is that thrust vectoring is more critical for flight control of tailless aircraft. Another possible reason is that in terms of development potential, the YF-23’s nozzle does not possess the stealth advantage over vectoring nozzles that is widely assumed.

I would assume that tailless aircraft struggle with yaw control and stability, and 'flat' 2D TVC works in the pitch axis, so I don't think it would help there. Btw, not sure how close the J-36 is to actual production, but I would personally assume they're in no rush - and the prototypes we are seeing are somewhat experimental and are liable to undergo significant changes, kind of like how SAC tweaked the FC-31 for a decade before it was final. The nozzle changes might also not reflect design intent - I think it's important to pace out innovation to control risk, and advanced nozzle integration has been shown to be possible on existing engines. Most emerging flat nozzles come from adapting mature engines to the technology, as we've seen with the S-70 and Su-57 flat nozzle prototypes, which were put on modified AL-31 variants, not the news stuff. So going back to a more traditional nozzle could mean they've actually put in the new engines. and final nozzle integration is going to come later.

 

[Forest Green]

Massive Expansion At China’s ‘Area 51’​

The buildout of the remote flight-test base has accelerated sharply, and large new hangars suggest a specific type of aircraft may be arriving in the near future.

https://www.twz.com/news-features/chinas-area-51-is-undergoing-a-massive-expansion