Shenyang FC-31 / J-31 Fighter Demonstrator

ougoah said:

This depends. J-35 is there for PLAN and will have some significant enough differences to a PLAAF ground based J-31. Sure the changes are much less than a ground up fighter but when you already have J-20 and currently looking at 6th gen (one on the way out, one in, one being tested rule of thumb -> J-10/11/16, J-20, 6th gen). And have plenty of expensive work inducting and pairing manned platforms with drones. Is there really that much room in PLA budget for yet another line of similar (at best) performance 5th gen to one that you have more production facilities for and one you have over 7 years experience flying and refining? Probably not.

But we do need to remember that China operates differently and at times much less efficiently. Everyone has to have a slice of the cake and SAC may argue that PLAN slice of the cake isn't big enough. For that point, I very much think they should simply focus on export market for their J-31 ground based variant and not erode PLAAF capability and budget by pushing for something that represents a less than ideal bargain for PLAAF.

In any case we're (@Gloire) just internet enthusiasts talking and are not privy to all the confidential stuff that decision makers have. This is all just wagering on procurement.

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In all honesty.

I see more reason to get some 'upgraded 5th gen/stealth Flanker' or a '5th gen JH', which may or may not have internal bays, over a J-31 (since a J-31 is likely to only have, AT BEST, some cost advantages over the J-20 and maybe a very small stealth advantage).

Sure, without internal bays, it's inevitable gonna have pretty bad stealth, but it be able to have more weapons for ground attack or carry the PL missiles that has 400+ km range.
And then after firing its missiles, it's gonna 'go back' to having stealth (likely less than J-20 and J-35 but a lot better than like J-16 and J-15).

Or alternatively, going the JH route and also optimize/go for more speed while being able to carry a big load (and have some stealth, in fact, kind of a upgraded and better F-111 with some stealth optimizations)

As for a cheaper and smaller homeland defense or interceptor (kind of like J-10), well I honestly see that role more easily fulfilled with drones.

Michaelsinodef said:

In all honesty.

I see more reason to get some 'upgraded 5th gen/stealth Flanker' or a '5th gen JH', which may or may not have internal bays, over a J-31 (since a J-31 is likely to only have, AT BEST, some cost advantages over the J-20 and maybe a very small stealth advantage).

Sure, without internal bays, it's inevitable gonna have pretty bad stealth, but it be able to have more weapons for ground attack or carry the PL missiles that has 400+ km range.
And then after firing its missiles, it's gonna 'go back' to having stealth (likely less than J-20 and J-35 but a lot better than like J-16 and J-15).

Or alternatively, going the JH route and also optimize/go for more speed while being able to carry a big load (and have some stealth, in fact, kind of a upgraded and better F-111 with some stealth optimizations)

As for a cheaper and smaller homeland defense or interceptor (kind of like J-10), well I honestly see that role more easily fulfilled with drones.

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A VLO/LO JH-xy would be much more valuable to PLAAF for both A2G and A2A but the development cost for the program would not be comparable to making the required changes to J-35 into J-31. In any case, it's all the more reason why PLAAF wouldn't or shouldn't be blowing funds on inducting a J-31.

A smaller, full VLO all-aspect stealth fighter to accompany J-20 can have its purpose better fulfilled by a large UCAV platform similar to Dark Sword. Unmanned - manned pairings are required anyway unless these heavy air superiority UCAVs represent the position covered by the "6th gen fighter" PLAAF is actually after, essentially having manned pilots replaced as part of one defining feature of next generation for PLAAF.

Get economies of scale with all those various UCAV platforms China is deploying. Forget J-31. J-35 for PLAN just so it can fit that many more fighters onboard carriers and J-31 for a ground based export 5th gen fighter to nations who can't/won't buy F-35.

blindsight said:

To some point, all of your current CVs have been equipped with enough J-35s, but you still keep the same production rate of 30/yr. Let's say you have to wait 4 yrs for your next CV, so you'll come up with more than 100 J-35s waiting for it?

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Again, you will need more J-35s than just the complement that goes on deck. What that number is, I can't say.

blindsight said:

But if you look at the whole PLA and China's defense industry, the J-35 will be there anyway, so adding the J-31 is not really like adding a type...

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I think it's fair to say that PLAAF even in optimal circumstance would not get J-31 before PLAN gets J-35, since naval variant is clearly the focus here. Let's say PLAN start getting naval variant in 25 in small batch production and then increase until some kind of in service status in 27. PLAAF could theoretically start getting it in 27/28. By then, there will be 600 J-20s. We will get 100 J-20s per year.

Where does production rate for J-35 need to be for its acquisition cost to be competitive with J-20? Remember, J-20 acquisition cost is only a little more than J-16.

Unless PLAAF has the same sustainment system as PLANAF, how does adding a new aircraft type and engine type affect sustainment complexity? The latter is possibly a bigger issue than the former, since WS-19 is not used anywhere right now.

Funding the J-35 was a way to keep Shenyang viable. So that they can have competition between Chengdu and Shenyang.
I also suspect the J-35 might have a lower mass fraction than the J-20. It will probably have a better thrust-to-weight ratio.
The J-35 uses 3D printing as well as more modern design tools. Larger single pieces are used.
This way the Navy also gets an aircraft design that is specifically designed to suit them.

I doubt there will be a cost advantage for J-35 initially. The engines aren't as well developed like you said. Time between overhauls and engine lifetime will likely be lower initially. Low series production will increase cost per engine.

Isn’t the J-20 an air superiority fighter? Even more, isn’t the J-20A a high altitude optimized aircraft? Surely the PLAAF can’t have its entire 5th generation fleet as a single air superiority fighter?. It needs to have a multi-role companion, the J-31.

It’s not only about cost, they can’t just put all their eggs in one basket, what if it gets hacked, the pilot forcefully ejected and the aircraft flown to a US base? or what if US radar finds a way to detect the J-20s smaller body panels?

There is no end of possibilities of how a single egg can be broken.

For me, I hope the J-31 is built in factories all over the world, from China, Brazil, Algeria, Saudi, Pakistan, Indonesia to pretty much the majority of large BRICS countries, and I expect them to export to their local regions, or others even. I can see over a thousand being built worldwide, maybe more as there could be over 3000 F-35s one day, and it should becoming very affordable, especially with WS-13 engines.

These countries, surely also members of the GSI, would use their own components and drones/wingmen where available.

I also think that from a commercial standpoint, China is aiming to have a competitive product in every single category that exists. This means there must be a place for competition against all F-35A, F-35B, F-35C. Today, China is the only nation on earth selling 5th generation fighter factories.

It also means there should be a heavy 5th generation flanker type at some point in the future, as well as EW versions because China has to have an offering to compete against F-15EX.

Andy1974 said:

Isn’t the J-20 an air superiority fighter? Even more, isn’t the J-20A a high altitude optimized aircraft? Surely the PLAAF can’t have its entire 5th generation fleet as a single air superiority fighter?. It needs to have a multi-role companion, the J-31.

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1, J-20 excel at high altitude high speed doesn't make it less capable in low altitude & low speed.
2, VLO attacker need a weapon bay deep enough that can carry A2G munition like F-35 does. I failed to see why J-20's bigger air frame is a draw back.
So, instead of multi-role companion, why not multi-role variant? Same goes EW version J-20.
And remember it's 2024, 6th gen is on the horizon already, does it make sense to mass induct a 2nd 5th gen jet for PLAAF that's at best 10 years late?

About the export market though, it make sense for China to offer a F-35 alternative but export the production line doesn't make sense.
It's not like cold war.

The J-20 is multi-role. And it has about the same sized internal bays as the J-35.
The difference is one is a heavy fighter (J-20) and the other is a medium fighter (J-35).

gelgoog said:

The J-20 is multi-role. And it has about the same sized internal bays as the J-35.
The difference is one is a heavy fighter (J-20) and the other is a medium fighter (J-35).

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Well, if they don't mortify the main weapon bay to accommodate A2G munition, J-20 is not gonna maintain VLO for multi-role.
Same goes for J-35.

minime said:

1, J-20 excel at high altitude high speed doesn't make it less capable in low altitude & low speed.
2, VLO attacker need a weapon bay deep enough that can carry A2G munition like F-35 does. I failed to see why J-20's bigger air frame is a draw back.
So, instead of multi-role companion, why not multi-role variant? Same goes EW version J-20.
And remember it's 2024, 6th gen is on the horizon already, does it make sense to mass induct a 2nd 5th gen jet for PLAAF that's at best 10 years late?

About the export market though, it make sense for China to offer a F-35 alternative but export the production line doesn't make sense.
It's not like cold war.

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I think the J-31 platform would be better for future development than the J-20, there can be an EW focused version, and it could be possible to develop a BIGGER version, scaled up and designed for dual WS-15 engines, to take over the J-16 and J-16D roles, let’s call it a hypothetical J-36.

Developing J-36 from J-31 is going to be less expensive and time consuming than developing it from scratch, perhaps this has been planned from the start.

J-20, I think should be developed into an interceptor, and China can have a full range of 5th Gens, for example:

• J-20 Air superiority, Medium-High Altitude
• J-20A Air superiority, High Altitude
• J-20B Interceptor
• ——
• J-31 Medium Multirole
• J-35 Medium Multirole Carrier
• J-36 Heavy Multirole
• ——
• J-xx Light S/VTOL

Really? Why this strange classification as if the two known J-20 variants should have different role and what's a J-20B? AFAIK the twin-seater is said to get this designation maybe.

And even more a development from J-36 as a heavy fighter based on he J-35 makes simply no sense at all as long as it still uses the same airframe and only medium thrust engines.

Sorry, but this makes no sense at all.