Chengdu next gen combat aircraft (?J-36)

JF-17 saw rather major modifications to their intakes during the EMD phase as well (initial splitter intakes, then DSIs), and even J-20 201X prototypes saw a few minor modifications to inlet geometry and canopy shaping.

We'll need to wait for clearer images to see where, if anywhere else the second J-36 prototype had changes, but based on what we've seen so far it's still quite consistent with a EMD prototyping phase.

Deleted various posts about the TWZ article which were essentially just throwing angry emotions around.

If one wants to post the TWZ article or any other to have a productive discussion, I encourage everyone which responds to it, to don't react with so much irritation and annoyance and be constructive, and for whoever posts it to offer some kind of constructive commentary rather than an implied or explicit "look at those idiots".

I wonder what the timeline looks like for the J36 program then , cause these changes are not small.
It seems that the whole PLA 6th gen program is aiming for an operational date of 2030 or later .

GT article is pretty positive, it cherry picks foreign news reports and experts to say this is a big step towards maturity.

Another foreign aviation news outlet, Air Data News, claimed in a report on Tuesday that the evolution seen in the second aircraft may indicate that its manufacturer is close to the final production design.

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It chooses these words carefully, I believe.

wssth0306 said:

I wonder what the timeline looks like for the J36 program then , cause these changes are not small.
It seems that the whole PLA 6th gen program is aiming for an operational date of 2030 or later .

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It is going to be earlier than the pessimists expect and later than what the optimists expect.

People need to understand that there is no precedence for this class of aircraft so as trailblazers, AVIC will inevitably encounter difficulties.

siegecrossbow said:

It is going to be earlier than the pessimists expect and later than what the optimists expect.

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Without knowing what is considered optimistic and pessimistic, that doesn't really say anything.

siegecrossbow said:

People need to understand that there is no precedence for this class of aircraft so as trailblazers, AVIC will inevitably encounter difficulties.

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I agree with this but I don't think the changes we are seeing between prototype 1 and 2 are reflective of any difficulties so much as integrating planned changes.

After all, JF-17 changed from splitter intakes to DSI intakes doing EMD prototyping as well, which was a fairly major change for a simpler aircraft. It's not unprecedented for a more complex aircraft like J-36 to incorporate planned advancements as part of its EMD airframes.

wssth0306 said:

I wonder what the timeline looks like for the J36 program then , cause these changes are not small.
It seems that the whole PLA 6th gen program is aiming for an operational date of 2030 or later .

Click to expand...

Changes that look big cosmetically may not always reflect critical impacts on development schedule. Sometimes it depends on other preliminary pipeline of work done on a revision before you employ the changes in integrated testing (for example if they flew a bunch of small scale demonstrators and have characterization data from those). Each design feature and component has their own risk assessment profile that doesn’t always match with the visual impression.

Overall though I would not deem these changes to necessarily reflect major lengthening of expected schedules because they were made very early in the R&D timelines, where your testing is more about preliminary findings and characterization than about verifying and validating every system and detail to be clear for production. On the other hand what it does suggest is that they haven’t quite yet reached full design freeze. That may be a function of the project design if they’ve set things up toward a more iterative modularized approach, or it may be a sign of development maturity, though as other have said earlier seeing these kinds of changes only 1 year into first flight is actually not that surprising.

Blitzo said:

Without knowing what is considered optimistic and pessimistic, that doesn't really say anything.




I agree with this but I don't think the changes we are seeing between prototype 1 and 2 are reflective of any difficulties so much as integrating planned changes.

After all, JF-17 changed from splitter intakes to DSI intakes doing EMD prototyping as well, which was a fairly major change for a simpler aircraft. It's not unprecedented for a more complex aircraft like J-36 to incorporate planned advancements as part of its EMD airframes.

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siegecrossbow said:

It is going to be earlier than the pessimists expect and later than what the optimists expect.

People need to understand that there is no precedence for this class of aircraft so as trailblazers, AVIC will inevitably encounter difficulties.

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A good general rule of thumb for R&D is if you see big design revisions are early in the development schedule this probably means the project hasn’t quite reached final design freeze stage. If it’s showing up late into the development schedule it’s more likely to reflect some problems.

latenlazy said:

Changes that look big cosmetically may not always reflect critical impacts on development schedule. Sometimes it depends on other preliminary pipeline of work done on a revision before you employ the changes in integrated testing (for example if they flew a bunch of small scale demonstrators and have characterization data from those). Each design feature and component has their own risk assessment profile that doesn’t always match with the visual impression.

Overall though I would not deem these changes to necessarily reflect major lengthening of expected schedules because they were made very early in the R&D timelines, where your testing is more about preliminary findings and characterization than about verifying and validating every system and detail to be clear for production. On the other hand what it does suggest is that they haven’t quite yet reached full design freeze. That may be a function of the project design if they’ve set things up toward a more iterative modularized approach, or it may be a sign of development maturity, though as other have said earlier seeing these kinds of changes only 1 year into first flight is actually not that surprising.

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IMO it all depends on whether the rest of the aircraft has "airframe scale" changes like YF-22->F-22 or X-35->F-35 or J-20 sn 200X -> sn 201X.

Because so far, outside of the intakes, MLG and exhausts, the rest of the aircraft's planform and geometry looks largely the same as the first airframe, which strikes me as more of a glorified difference between JF-17 PT3 and PT4, i.e.: implementing likely planned, "significant but localized" changes rather than a wholesale redesign of the aircraft.

Blitzo said:

IMO it all depends on whether the rest of the aircraft has "airframe scale" changes like YF-22->F-22 or X-35->F-35 or J-20 sn 200X -> sn 201X.

Because so far, outside of the intakes, MLG and exhausts, the rest of the aircraft's planform and geometry looks largely the same as the first airframe, which strikes me as more of a glorified difference between JF-17 PT3 and PT4, i.e.: implementing likely planned, "significant but localized" changes rather than a wholesale redesign of the aircraft.

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I agree. The scope of characteristics encompassed in these changes, as far as we can say with the current collection of photos, are not as expansive as they might appear.

Caret to DSI shouldn’t affect overall flight characteristics, just the airstream conditions at the engine face in specific flight envelopes (and the engines themselves should have their own robustness tolerance margins for different airstream conditions).

Removal of nozzle flaps might be a decision to simplify. They’re also likely to have minimal impact in aerodynamic performance, and may even reduce some testing burdens if the flaps were removed specifically due to some adverse characteristics found during testing.

Landing gear also doesn’t affect flight performance and its critical parameters can probably be validated with full scale static models. I think if we had seen any significant changes to the planform or control surface schemes that would have indicated something more major.

Tomboy said:

At this point with all the chest thumping in this forum recently I'm just interested in how we actually stack up with the competition, are we truly that far ahead or are we just being overconfident. If you are so knowledgeable why don't you give us lesser folks some pointers on how exactly is this a improvement.

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As per the United States Air Force, Chinese weapons development programmes are up to 4x faster.

As per the Pentagon, the American aerospace industry can't handle a second 6th gen aircraft programme, without impacting the F-47 programme which was just awarded.

Then look at the difference between China and the USA in terms of STEM personnel, industrial depth and capacity, R&D output, etc

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The only reasonable assumption is that China is ahead.