J36

A second prototype of China’s very heavy J-36 ‘fighter’ has emerged with major refinements. These alterations, compared to the first J-36 airframe, point to the program very much being iterative in its process. They also add to the evidence of what we already posited, that the first J-36 aircraft was not a highly mature, near-production-representative design, as some had repeatedly claimed. You can read our very in-depth initial analysis on the J-36 here.

Images of this second example of the J-36 emerged today on social media, showing the aircraft flying through Chinese skies from multiple angles. The images were likely taken near Chengdu Aircraft Corporation’s major plant in its namesake city, where initial flight testing of the first aircraft publicly emerged on December 26, 2024.

The new images show the same overall modified delta design we have become accustomed to, but with some major features changed in readily visible areas.

Exhaust

The first J-36 had exhausts that were recessed from the trailing edge atop the aircraft, an arrangement loosely similar to what was found on the Northrop YF-23. This is a noted low-observable (stealth) design cue and made sense for a big three-engined jet that optimized stealth, speed, and efficiency over raw maneuverability. Now we are seeing what appears to be three angular exhaust nozzles that look very similar to the two-dimensional thrust vectoring exhaust nozzles on the Lockheed F-22 Raptor — a design trait and capability that is also present on China’s new J-XDS heavy tailless stealth fighter.

The exhaust changes have major implications. First off, if indeed this is two-dimensional (2-D) thrust vectoring, why is it needed for what appears to be a very heavy multi-role tactical jet that is less fighter than regional bomber? It could be that a higher degree of fighter-like performance is desired, pointing to that mission set being prioritized. It could also be to solve certain stability and maneuverability issues during certain phases of flight. Tailless designs are inherently extremely unstable. Thrust vectoring can help with this and maximize potential performance throughout the flight envelope, including at very high altitudes.

It’s also possible that just a lower thrust vectoring ‘flap’ is being employed here and not a full 2-D exhaust system. This seems less likely, but it is possible, and could provide some degree of extra control without such a heavy redesign of the upper empennage.

The new, more heavily serrated design likely has an impact on the jet’s low-observable qualities, at least from the rear aspect. In order to pull off full 2-D thrust vectoring, the aircraft’s rear upper rear fuselage design would also have to be significantly remodeled, with the engine nacelles being pushed back to the trailing edge. The full extent of the changes to the upper end of the J-36 are unclear, but this was not a case of just slapping a thrust vectoring nozzle on there, as the original exhausts were deeply recessed forward of the trailing edge. Again, it looks like Chengdu designers traded some signature control for performance here.

Weight is also an issue, as thrust vectoring nozzles add complexity and mass, but for such a larger and heavy jet as it is, the impact is likely minimal.

Inlets

The original J-36 aircraft’s F-22-like caret lower inlets have been significantly revised. In our original analysis, we discussed how it was interesting that the dorsal intake uses divertless supersonic intake (DSI), which China is now accustomed to using on its aircraft, but the two lower intakes were a trapezoidal caret-like design. This has changed in the new iteration of the jet, with what appear to be DSI intakes taking the place of the original ones. The lower lips of these intakes also sweep forward, which is another trademark for this kind of design, and is especially pronounced on low-observable ones.

Landing Gear

The J-36’s tandem two-wheeled main landing gear — which provided a stark indication of how heavy the aircraft was — has been totally redesigned, with a twin-wheel side-by-side truck arrangement taking its place. While this may necessitate a deeper main gear well for stowage when retracted, it requires less area and smaller main gear doors, among other advantages. This is a relatively dramatic and surprising refinement, to say the least.

Other Takeaways

Another small tweak appears to be a less elaborate air data probe jutting out from the second J-36’s nose, although this could be an artifact of the high compression of the images. There are certain to be other outward tweaks to the J-36’s original design that we cannot see in these limited-resolution images taken in poor lighting. We can expect some refinements in shaping, especially where the intakes blend with the fuselage and other areas, although we cannot confirm this at this time. This is all in addition to what’s on the top of the new aircraft, which we haven’t seen at all at the time of writing.

Overall, these major changes a year after we first saw the design, point to an aircraft still very much in the stages of flight test demonstration/development and possibly to an accelerated iterative design scheme used to rush the aircraft into a production-like state. This new aircraft could also be an alternative configuration, not an evolutionary one, but that seems less likely at this time.

As we have repeatedly stated, the progress China is making when it comes to advanced combat aircraft is absolutely stunning. And yes, these aircraft are far more than their outward appearance and would need to rely on superior sensor and communications technology, low-observable material science, total force integration, and of course, operator and integrated training, in order to win the day. But taken at face value, China’s rapid progress with so many diverse platforms in such a short time is remarkable.

That being said, there are some that declare everything they see as late in development and near ready for production, regardless of the evidence. This is usually framed against an inflammatory U.S.-China competition narrative. Seeing this new iteration of the J-36 should underline just how fast China is working to refine the design, and it’s likely this was well in the works when the first example took flight. Still, claims that the J-36 was very far along in its development and even production representative when it first flew should now be put to rest.

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