Shenyang FC-31 / J-31 Fighter Demonstrator

stannislas said:

No, and stop making what your believe or even imaging as it's a fact.

In fact there is no evidence of that the landbased J-XY/35 is concret, SAC state multipl times that FC-31 program is 'one aircraft four varients' and most recently in Zhuhai airshow it becomes 'one aircraft three varients', and people just making up rumors of PLAAF will adapt landbased FC-31 based on this. This is what SAC designer want, but whether if it is PLAAF want, is still an unknown.

But regradless of what, it's a program fundamental on the FC-31 program, and like I stated few days ago with you, it will be greatly cost ineffective to reverse the design from J-35 back to a land based aircraft than develop from FC-31 V2.0 with some J-35 technologies.

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I don't care if you want to refer to it as "PLA FC-31" instead of "land based J-XY/35".
My point is that the "PLA FC-31" won't be anymore related to FC-31v1/v2 than F-35 is to X-35.

stannislas said:

You do understand the word and concept of 'modular', do you? it means that if future design is money saving or more effective, you can swap your old equipment with this fancy and cheaper one

People has using this on programming for decades, and just one of the most popluar language 'python' as an example, almost all the package are replacable, as long as they are in the same major python version, 2.0 or 3.0, so for example the most Python 3.10 improve the iteration function effectioncy by a lot, that means if I update to 3.10 all my codes in Python 3.0+ can enjoy this update.

Same goes with J-20 and FC-31 in this case, the idea of being the modular is to setup a framework for future updates, it's intend to co-op with 'additional technology advancement and newer production techniques.', so when better and cheaper equipment is coming, J-20 and J-35 could use it straight way.

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Of course I understand what modular means.
You can modularly design an aircraft to have LRUs in its avionics suite to have hardware changed relatively easily. You can design its software to be updated with block upgrades more easily.

That does not mean you can "modularly" change an aircraft's entire airframe from one production method to another, or to change an aircraft's RAM advancement without substantial redesign and change in the production line.

stannislas said:

I will repeat again, physically size is never a cost sensitive issue in modern days aircraft. In fact, even between F-15 and F-15, the biggest cost difference in terms of difference is engine.


I hate to repeat this argument with you again, just curious, why US is ok with USAF with roughly 1000 F-35 and turn into 6th gen fighter, whereas PLAAF has to stick with in your case

In fact, a rumor I heard recently was that, there haven't been a single J-10C in PLA paint since CAC started to export J-10CP to Pakistan. Have you ever realize that PLAAF is actually much more prefer long range J-20 rather than medium range fighter, and why can't after J-20 reach 1000, the production just continue on, say another 500? Given the major enermy of China is from the Pacific, long range is a must, so this is highly likely to be the case.


or another possible case, with no J-XY at all;
2022-2025: J-20, J-16, J-10C
2025-2030: J-20, cessation of J-16 and J-10C shortly after 2025(?),
2030-2035: J-20, 6th gen
2035-2040: 6th gen

Seriously, we discussed this as well, how many landbased J-XY PLAAF will buy could very much depend on the evaluation results of J-35, which will only make it slower, so 2025-2030 is highly unlikely to start to massively produce landbased J-XY.

In fact, ask yourself, short range of fighter like J-10 even found its difficulties around Taiwan, why you are still expecting PLAAF to fall into this problem on their 5th gen or 6th gen fighter?
Yang Wei on his future airwarfare paper stated 'long range' as 2nd most import factor. This is also the key requirement for NGAD, if both side taken this so seriously, why they are still looking for a short range medium size 5th gen fighter?

I seriously suggest you take a rethink over this mindset that 'PLAAF must have a medium size 5th gen fighter', it has no concreate evidence rather than some wishful thinking on Weibo, it's not as cheap as you imagine, it's not going to give any maintaince advantage beside of open another huge supply chain, and it's contriduct to PLA A2AD idea.

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Where did I ever say that the PLAAF must have a medium size 5th gen fighter?

Let me be clear -- at present, with the news we've had over the last month (especially WRT J-20 production), I do not know if it is sensible for the PLA to pursue a land based medium size 5th gen fighter or not.
After all, it depends on things like J-20's production rate and production run, how 6th gen testing and development and testing goes, and how high end MUMT UCAVs might evolve in capability and maturity.
It may well be possible that they might forgo a manned medium weight 5th gen fighter entirely.


BUT, what I'm saying is that if they do end up going for a "PLA FC-31"/"land based J-XY/35" as a medium sized 5th gen fighter, it will still have significant improvements designed to lower production costs and operational costs compared to J-20, and yes that is on top of J-20's existing degree of maintainability (i.e.: same as what latenlazy said in post 7051).

And at present, seeing as we are PLA watchers, we have to depend on rumours to do future projections, and currently we are still expecting a "PLA FC-31"/"land based J-XY/35" to emerge, thus we are obliged to factor that into our projections.
We receive rumours, and we try to make sense of them.
If in coming months or years we receive rumours that the PLA has decided to not pursue a "PLA FC-31"/"land based J-XY/35" then that's perfectly fine as well. But until we get those indications, we are obliged to respect that such an aircraft is likely in advanced stages of development with PLA funding, and try to rationalize how it may fit into the future.

Blitzo said:

I don't care if you want to refer to it as "PLA FC-31" instead of "land based J-XY/35".
My point is that the "PLA FC-31" won't be anymore related to FC-31v1/v2 than F-35 is to X-35.

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Keep struggle with naming won't you argument more persuasive
Of course,

Blitzo said:

My point is that the "PLA FC-31" won't be anymore related to FC-31v1/v2 than F-35 is to X-35.

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But so does PLAAF to the J-35, as it's a naval fighter, despite the technology status, same or even more modification need to be done

Blitzo said:

That does not mean you can "modularly" change an aircraft's entire airframe from one production method to another, or to change an aircraft's RAM advancement without substantial redesign and change in the production line.

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It's hard to tell, we can use F-35 as a reference, for example block 4 are major update which requires a production line change, but does that hesitate Lockheed Martin? No, they change it anyway, because change in production line isn't the end of the word, in fact, production changes always in almost every industry, large or small.
Given how military aircraft production is like right now, I will say it's more approperate to call it a 'implusive craftsman line' than a 'production line',

Over some most recent interview with PLA pilots during the Zhuhai airshow, they mentioned that J-20 is under continuous update, just like F-35. In fact, I hardly found any major change as big as from J-10A to J-10C, if they can change the inlet of the aircraft which even alter the fundamental of the aerodynamic of an aircraft, what updates can't they do?

Blitzo said:

Where did I ever say that the PLAAF must have a medium size 5th gen fighter?

Let me be clear -- at present, with the news we've had over the last month (especially WRT J-20 production), I do not know if it is sensible for the PLA to pursue a land based medium size 5th gen fighter or not.
After all, it depends on things like J-20's production rate and production run, how 6th gen testing and development and testing goes, and how high end MUMT UCAVs might evolve in capability and maturity.
It may well be possible that they might forgo a manned medium weight 5th gen fighter entirely.

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I'm glad you said that, but does this

Blitzo said:

BUT, what I'm saying is that if they do end up going for a "PLA FC-31"/"land based J-XY/35" as a medium sized 5th gen fighter, it will still have significant improvements designed to lower production costs and operational costs compared to J-20, and yes that is on top of J-20's existing degree of maintainability (i.e.: same as what latenlazy said in post 7051).

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contridict to what you were refering to?

For J-20 production, it need to depend on it's production rate and how 6th gen fighter goes?
But for landbased J-XY, you are able to directly jump from the idea, 'OK, based on the rumer PLA may acqusate some medium size fighter from SAC' to

Blitzo said:

All of which is to say, there may well be another good 800-1000 land based fighter aircraft that need replacement from 2025 to mid/late 2030s, on top of the demand for 1000 J-20s.

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???
Seriously? Why this time you don't take the middle ground and argue it step by step, like the procurement of land based J-XY might depend on the development of J-35 and how PLANAF and PLAAF evaluate it? or J-20 could produce even more to make up the gap? or even 6th come out quicker than we expacted?
But instead directly goes to another 800 - 1000 on top of 1000 J-20?

This make me wonder if you bought the idea too deep, and start to wish it become a reality.

stannislas said:

Keep struggle with naming won't you argument more persuasive
Of course,

But so does PLAAF to the J-35, as it's a naval fighter, despite the technology status, same or even more modification need to be done

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Your sentences do not make sense.

stannislas said:

It's hard to tell, we can use F-35 as a reference, for example block 4 are major update which requires a production line change, but does that hesitate Lockheed Martin? No, they change it anyway, because change in production line isn't the end of the word, in fact, production changes always in almost every industry, large or small.

Given how military aircraft production is like right now, I will say it's more approperate to call it a 'implusive craftsman line' than a 'production line',

Over some most recent interview with PLA pilots during the Zhuhai airshow, they mentioned that J-20 is under continuous update, just like F-35. In fact, I hardly found any major change as big as from J-10A to J-10C, if they can change the inlet of the aircraft which even alter the fundamental of the aerodynamic of an aircraft, what updates can't they do?

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Yes, I fully expect J-20 to have continuous updates to its avionics like F-35, and also to have refinements in its existing production techniques and signature reduction methods over time.

That is still a big difference to the extent of production advancements, and structural and inbuilt RAM options that the "PLA FC-31"/"land based J-XY" would be expected to have with 7 years of additional technological advancement compared to J-20.

stannislas said:

I'm glad you said that, but does this

contridict to what you were refering to?

For J-20 production, it need to depend on it's production rate and how 6th gen fighter goes?
But for landbased J-XY, you are able to directly jump from the idea, 'OK, based on the rumer PLA may acqusate some medium size fighter from SAC' to

???
Seriously? Why this time you don't take the middle ground and argue it step by step, like the procurement of land based J-XY might depend on the development of J-35 and how PLANAF and PLAAF evaluate it? or J-20 could produce even more to make up the gap? or even 6th come out quicker than we expacted?
But instead directly goes to another 800 - 1000 on top of 1000 J-20?

This make me wonder if you bought the idea too deep, and start to wish it become a reality.

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No, my position is fully internally consistent, here have a look:

1) It is possible that in the future, the PLA may not procure a medium weight 5th generation land based fighter, due to other capabilities emerging (combination of J-20 production rates increasing +/- 6th gen emerging earlier +/- MUMT UCAVs maturing and emerging)
2) At present, we still have significant long term rumours that there is a PLA funded "PLA FC-31"/"land based J-XY/35" project that we expect to emerge in the near future, which we cannot ignore.

So, right now we have to try to think "how does a "PLA FC-31"/"land based J-XY/35" make sense for the PLA's future fighter procurement".
IF, we get rumours that the "PLA FC-31"/"land based J-XY/35" is cancelled and the PLA is not interested -- then, we can start talking more seriously about a future without it.

Let me repeat myself -- I personally do not know if it is sensible for the PLA to buy a medium weight 5th gen fighter or not.

But whatever I think is sensible or not doesn't matter -- we do not get the luxury of trying to predict what the PLA might do if there are long term credible rumours that already exist.
If such rumours exist, then we are obliged to try to make sense of the rumours rather than trying to work against the rumours and make our own predictions.

If such rumours eventually are dispelled and we get news that information has changed, then great, we are again free to make our own predictions.

Blitzo said:

Your sentences do not make sense.

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whatever, make you own judgment

Blitzo said:

Yes, I fully expect J-20 to have continuous updates to its avionics like F-35, and also to have refinements in its existing production techniques and signature reduction methods over time.

That is still a big difference to the extent of production advancements, and structural and inbuilt RAM options that the "PLA FC-31"/"land based J-XY" would be expected to have with 7 years of additional technological advancement compared to J-20.

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Sure, some advancement techs from FC-31 may only possible to be adapted when major updates of J-20 is comming like the 3D print main structure components, but again this generation of fighter are designed in this way, that they can adapt continuouse updates. And if the update is too big, we can always have J-20B, C, D, E ...

Blitzo said:

No, my position is fully internally consistent, here have a look:

1) It is possible that in the future, the PLA may not procure a medium weight 5th generation land based fighter, due to other capabilities emerging (combination of J-20 production rates increasing +/- 6th gen emerging earlier +/- MUMT UCAVs maturing and emerging)
2) At present, we still have significant long term rumours that there is a PLA funded "PLA FC-31"/"land based J-XY/35" project that we expect to emerge in the near future, which we cannot ignore.

So, right now we have to try to think "how does a "PLA FC-31"/"land based J-XY/35" make sense for the PLA's future fighter procurement".
IF, we get rumours that the "PLA FC-31"/"land based J-XY/35" is cancelled and the PLA is not interested -- then, we can start talking more seriously about a future without it.

Let me repeat myself -- I personally do not know if it is sensible for the PLA to buy a medium weight 5th gen fighter or not.

But whatever I think is sensible or not doesn't matter -- we do not get the luxury of trying to predict what the PLA might do if there are long term credible rumours that already exist.
If such rumours exist, then we are obliged to try to make sense of the rumours rather than trying to work against the rumours and make our own predictions.

If such rumours eventually are dispelled and we get news that information has changed, then great, we are again free to make our own predictions.

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I'm in fact glad you stated in this way, and for most part I would agree,
but a straight jump from "how does a "PLA FC-31"/"land based J-XY/35" make sense for the PLA's future fighter procurement".
to "another 800 - 1000 on top of 1000 J-20" is just too big...

Also, as to the rumours, i don't know how to say this...
One of the reason I enjoy here at SDF is because this place is quite, 99% of rumors or nonsense from Chinese community won't get this far. Unlike Tieba/Weibo/Bilibili/Zhihu and some previous fourms like cjdby, feiyang, tiexue etc. you got so many unselected rumors every single day, and most of them are contridict to each other which make no sense at all. If you lucky, you were able to witness some long term rumours orignally formed, it often contains imagination, wishful thinking and very biased interperation over certain speech or documents. For me, land based J-XY/35 is just one of the regular rumors out there, since the first day J-20 was out, some people started to argue that J-20 is going to be dead expensive and SAC will have a cheaper medium size fighter out quickly, which would phase J-20 out. Then it got buffed when FC-31 is out, and again and again and again, and again by speaches like 'one aircraft 4 varients'.

I agree it's possible, but hey, i'm also expecting H-20 will show it's first picture today to steal the thunder of B-21, unlikely right? but who can tell.
In fact, when was the last time we were able to successfully predict PLA from rumors? How many things has PLA superised us since J-20? FC-31, 055, all kinds of missile, hypersonics, etc.
Right? things has few rumors always turn out become reality and a lot of long term rumers, for example the one come to my mind, stealth JH-7, has never become a thing, other than a model, things just change too much.

Instead of cost savings, could it be possible that the J-35 will be an overall improvement of the J-20?

-J-20 was developed largely during a time where they didn't have access to the hacked US data.
-Maybe they learned some lessons from developing the J-20.
-Maybe learned some tactics/doctrines in stealth use and can design current knowledge of stealth fighter skirmishing.
-No canards can help improve all aspect stealth.
-Maybe weapons bay that features 6 x PL-15's instead of 4?

gongolongo said:

-Maybe weapons bay that features 6 x PL-15's instead of 4?

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Impossible IMO

gongolongo said:

Instead of cost savings, could it be possible that the J-35 will be an overall improvement of the J-20?

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J-35/XY and J-20 are in different weight classes, so keep in mind the word "improvement" should be used carefully.
Also, "cost savings" should be viewed as directly being linked to availability and readiness, which in turn is linked with capability.

gongolongo said:

-J-20 was developed largely during a time where they didn't have access to the hacked US data.

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We have no idea if data from espionage would even be useful for actually developing an aircraft in the first place.

gongolongo said:

-Maybe they learned some lessons from developing the J-20.

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Yes, they definitely would have, and they would have had 7 years to build on it as I wrote in a previous post.
Lessons and advancements are expected. But primarily they are expected to be further advances in maintainability, ease of construction, ease of upgrades and so on. Things which improve readiness, cost.

gongolongo said:

-Maybe learned some tactics/doctrines in stealth use and can design current knowledge of stealth fighter skirmishing.

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In the sense that "lessons in operating J-20 will inform priorities and design choices in J-XY/35" -- yes. But something as specific as you described? Who knows.

gongolongo said:

-No canards can help improve all aspect stealth.

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That's not how it works.

gongolongo said:

-Maybe weapons bay that features 6 x PL-15's instead of 4?

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No. At the moment we expect J-XY/35's main weapons bay to be the same dimensions as that of J-20's ventral bay. We are awaiting pictures to see if that ends up being true.
But the weapons bay itself will certainly not be larger.

There is a new BVRAAM that will allow J-20 and J-XY/35 to carry six of them in their ventral bay, but it is a new missile overall.

stannislas said:

whatever, make you own judgment


Sure, some advancement techs from FC-31 may only possible to be adapted when major updates of J-20 is comming like the 3D print main structure components, but again this generation of fighter are designed in this way, that they can adapt continuouse updates. And if the update is too big, we can always have J-20B, C, D, E ...


I'm in fact glad you stated in this way, and for most part I would agree,
but a straight jump from "how does a "PLA FC-31"/"land based J-XY/35" make sense for the PLA's future fighter procurement".
to "another 800 - 1000 on top of 1000 J-20" is just too big...

Also, as to the rumours, i don't know how to say this...
One of the reason I enjoy here at SDF is because this place is quite, 99% of rumors or nonsense from Chinese community won't get this far. Unlike Tieba/Weibo/Bilibili/Zhihu and some previous fourms like cjdby, feiyang, tiexue etc. you got so many unselected rumors every single day, and most of them are contridict to each other which make no sense at all. If you lucky, you were able to witness some long term rumours orignally formed, it often contains imagination, wishful thinking and very biased interperation over certain speech or documents. For me, land based J-XY/35 is just one of the regular rumors out there, since the first day J-20 was out, some people started to argue that J-20 is going to be dead expensive and SAC will have a cheaper medium size fighter out quickly, which would phase J-20 out. Then it got buffed when FC-31 is out, and again and again and again, and again by speaches like 'one aircraft 4 varients'.

I agree it's possible, but hey, i'm also expecting H-20 will show it's first picture today to steal the thunder of B-21, unlikely right? but who can tell.
In fact, when was the last time we were able to successfully predict PLA from rumors? How many things has PLA superised us since J-20? FC-31, 055, all kinds of missile, hypersonics, etc.
Right? things has few rumors always turn out become reality and a lot of long term rumers, for example the one come to my mind, stealth JH-7, has never become a thing, other than a model, things just change too much.

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I am not particularly married to the idea of the PLA buying a "PLA FC-31"/"land based J-XY/35" as a medium weight 5th generation fighter.
As I said, I'm very open to the idea that they might not buy it.

But my assessment of the rumours as they are at present is that such a project is currently ongoing and we cannot ignore it, thus we are obliged to try to make sense of it until such a time that the rumours change.

There is a reason why surprises are surprises -- because we cannot predict them, because rumours were either non-substantial or lacking in them.
(Oh, and J-20, FC-31, 055 were actually not surprises at all -- for J-20 we had a good half decade of consistent rumours, for FC-31 we had 2 years of rumours prior, and for 055 we had 3 or more years of rumours as well)


If you just want to ignore the rumours and you believe that the "PLA FC-31"/"land based J-XY/35" isn't real or being developed, or that the PLA isn't going to buy it, that's fine.
But from where we are sitting right now, at the moment we do expect it, so we have to factor it in a way that makes sense. It has nothing to do with how much we like or dislike the particular aircraft.

Blitzo said:

I am not particularly married to the idea of the PLA buying a "PLA FC-31"/"land based J-XY/35" as a medium weight 5th generation fighter.
As I said, I'm very open to the idea that they might not buy it.

But my assessment of the rumours as they are at present is that such a project is currently ongoing and we cannot ignore it, thus we are obliged to try to make sense of it until such a time that the rumours change.

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In fact this thing is a ongoing project is not a rumor at all, the SAC has confirmed multiple times, it's just want SAC or AVIC develop stated has nothing to do with whether PLA will buy it or not, and it's even far away from PLA may buy 800-1000 of it on top of J-20.

Blitzo said:

There is a reason why surprises are surprises -- because we cannot predict them, because rumours were either non-substantial or lacking in them.
(Oh, and J-20, FC-31, 055 were actually not surprises at all -- for J-20 we had a good half decade of consistent rumours, for FC-31 we had 2 years of rumours prior, and for 055 we had 3 or more years of rumours as well)

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no no, those rumors by then were very far away from the later reality.

before J-20, we got J-14, in fact multiple different CGs of it, we got enhanced J-10, J-11, even J-8, but nothing close to what J-20 was like in the end beside of that J-14 CG from Gaoshan, and he end up cleared that he has no source beyond his imagination. most people by then believed that China should have something on going, but when it could come out? who know? 2020?

for FC-31, I have cleared that, it has nothing to do with rational analysis, but ergo from SAC fanboys, and just before rumor almost fade out, FC-31 was out, then everything went on once again.

for 055, the rumors by than was more towards 052E, and most people in chinese communities were quite happy with 8000t, a brand new 10000t+ destoryer was actually expected no earlier than 2020 by then

Blitzo said:

If you just want to ignore the rumours and you believe that the "PLA FC-31"/"land based J-XY/35" isn't real or being developed, or that the PLA isn't going to buy it, that's fine.
But from where we are sitting right now, at the moment we do expect it, so we have to factor it in a way that makes sense. It has nothing to do with how much we like or dislike the particular aircraft.

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I'm not saying we are going to ignore rumors, rumor is a big part of Chinese military watching I say. But the important is that we need to distingish what is the base of such rumor, and which part is just people's expactation. There were a lot of rumors, especially between SAC and CAC a few years back, are intentionally formed and mixed with a lot of wishful thinking, thus we need to review and treat more carefully.

stannislas said:

In fact this thing is a ongoing project is not a rumor at all, the SAC has confirmed multiple times, it's just want SAC or AVIC develop stated has nothing to do with whether PLA will buy it or not, and it's even far away from PLA may buy 800-1000 of it on top of J-20.


no no, those rumors by then were very far away from the later reality.

before J-20, we got J-14, in fact multiple different CGs of it, we got enhanced J-10, J-11, even J-8, but nothing close to what J-20 was like in the end beside of that J-14 CG from Gaoshan, and he end up cleared that he has no source beyond his imagination. most people by then believed that China should have something on going, but when it could come out? who know? 2020?

for FC-31, I have cleared that, it has nothing to do with rational analysis, but ergo from SAC fanboys, and just before rumor almost fade out, FC-31 was out, then everything went on once again.

for 055, the rumors by than was more towards 052E, and most people in chinese communities were quite happy with 8000t, a brand new 10000t+ destoryer was actually expected no earlier than 2020 by then


I'm not saying we are going to ignore rumors, rumor is a big part of Chinese military watching I say. But the important is that we need to distingish what is the base of such rumor, and which part is just people's expactation. There were a lot of rumors, especially between SAC and CAC a few years back, are intentionally formed and mixed with a lot of wishful thinking, thus we need to review and treat more carefully.

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The point of tracking rumours is that they often evolve and change with time, and sometimes they can eventually be updated in a manner where previous plans and rumours are confirmed to be cancelled.


That's why it takes years of continuous rumour tracking for us to be able to build a degree of consensus.

In the case of J-20, there were so many different names for it initially like J-XX and J-13 and J-14, and then overtime it standardized more to J-XX, and it standardized to rumours that it would be a canard delta heavyweight stealth fighter from CAC powered by heavy thrust engines, and then in the lead up to 2010/11 the designation began to be rumoured as J-20.

Rumours are not static -- old rumours are always updated with new information either confirming that they are still on track, or that something has changed.



You seem very much against SAC fanboys and actively not a fan of the idea of a "PLA FC-31"/"land based J-XY/35".

But using the standard method of rumour tracking that has served us pretty damn well since the mid 2000s, at present we have no choice but to acknowledge that such a project is likely in the works and we have to factor it into our calculations.

If tomorrow we get credible rumours telling us it is cancelled and PLA are not buying it, great. But until then, we have no choice.