Shenyang FC-31 / J-31 Fighter Demonstrator

To admit - even if it might be short-sighted or naive due to a lack of understanding of the Aviation scene in China – I can’t think that SAC can stem the sum to develop a fifth generation fighter by its own income alone … especially with reportedly a second prototype now under discussion.

I can’t think that a state-owned enterprise like SAC is free enough to develop such a costly (both in real money but also manpower and even more subsystems) without any given budget.

If this is due to a certain operational requirement from either the PLAAF or PLANAF is not the question, it might even simply be a political move to keep SAC busy, to not widen the gap between SAC and CAC even more … I think we can imagine a few more possible reasons. But I’m almost sure that there is more behind than simply a PR-gag.

Deino

Deino said:

To admit - even if it might be short-sighted or naive due to a lack of understanding of the Aviation scene in China – I can’t think that SAC can stem the sum to develop a fifth generation fighter by its own income alone … especially with reportedly a second prototype now under discussion.

I can’t think that a state-owned enterprise like SAC is free enough to develop such a costly (both in real money but also manpower and even more subsystems) without any given budget.

If this is due to a certain operational requirement from either the PLAAF or PLANAF is not the question, it might even simply be a political move to keep SAC busy, to not widen the gap between SAC and CAC even more … I think we can imagine a few more possible reasons. But I’m almost sure that there is more behind than simply a PR-gag.

Deino

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I agree with Deino.

For a plane as sophisticated as J-31, it requires a lot of bleeding edge technology and sub-systems. It's true there's F20, which most people use as example for non-government-backed project. But this plane was not ahead of its time, all its subsystems are modified off-the-shelf ones from other mature planes and are ready to be produced at moments notice. Whereas J-31 is a frontier product. All sub-systems, including radar, UHD, specialized computer, coatings, specialized metals, all have to be designed and produced from scratch. SAC is only an integrator, they are only reponsible for integrating existing technologies. Without the coordination of a centralized planning body, it would be impossible to pull off something as sophisticated as J-31.

Anyone that really knows China would know that Chinese governmental agencies are very bureaucratic. Without the coordination and orders from above, no one would listen to one another. For example, J-31 needs special coatings, so SAC goes around to related institutes in Guizhou, Hefei and Shanghai to request help. If the project was 100% in-house, then no one from those institutes would listen. Even if they do, it would not be taken seriously, it would be just another project on the list (those have lived in China would understand what I'm talking about). However, because J-31 is blessed by the PLAAF and the central planning body, that's why it was able to roll out almost as soon as J-20, China's future backbone fighter.

It's hard to fathom a country as tightly run as China would have a lose cannon on the scale of J-31. If someone told me a plane like FC-1 or L-15 was done as an in-house project, I might believe it, since they're already mature technology. But for something as bleeding edge and forefront as J-31 to be 100% in-house, especially without the coordination of the PLA big wigs, I would just tell them....

I think the stereotype of the communist iron fisted control of everything is fiction. I've mentioned before that there's a competition between cities for the tallest most daring designs of buildings going on. It's said that in part is causing economic problems where cities are spending too much money in this competition. There are fewer players in the Chinese defense industries but there have been stories of arms companies going on their own to sell weapons around the world. The PLA was also said to have their own businesses that have nothing to do with military defense.

Verum said:

I agree with Deino.

For a plane as sophisticated as J-31, it requires a lot of bleeding edge technology and sub-systems. It's true there's F20, which most people use as example for non-government-backed project. But this plane was not ahead of its time, all its subsystems are modified off-the-shelf ones from other mature planes and are ready to be produced at moments notice. Whereas J-31 is a frontier product. All sub-systems, including radar, UHD, specialized computer, coatings, specialized metals, all have to be designed and produced from scratch. SAC is only an integrator, they are only reponsible for integrating existing technologies. Without the coordination of a centralized planning body, it would be impossible to pull off something as sophisticated as J-31.

Anyone that really knows China would know that Chinese governmental agencies are very bureaucratic. Without the coordination and orders from above, no one would listen to one another. For example, J-31 needs special coatings, so SAC goes around to related institutes in Guizhou, Hefei and Shanghai to request help. If the project was 100% in-house, then no one from those institutes would listen. Even if they do, it would not be taken seriously, it would be just another project on the list (those have lived in China would understand what I'm talking about). However, because J-31 is blessed by the PLAAF and the central planning body, that's why it was able to roll out almost as soon as J-20, China's future backbone fighter.

It's hard to fathom a country as tightly run as China would have a lose cannon on the scale of J-31. If someone told me a plane like FC-1 or L-15 was done as an in-house project, I might believe it, since they're already mature technology. But for something as bleeding edge and forefront as J-31 to be 100% in-house, especially without the coordination of the PLA big wigs, I would just tell them....

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I'm not sure how you get the idea that the J-31 is bleeding edge technolgy - because it does look like a twin engine version of the F-35?
The prototypes lack any outstanding features of the J-20 like EOTS or DAS counterparts.

I do have the impression the J-31 is supposed to be step down technologywise while being cheaper than the J-20. Take the J-31 airframe, put two upgraded WS-13 engines, a state-of-the art AESA radar and you do have a powerful and upgradable 5gen workhorse and/or export aircraft.

Pmichael said:

I'm not sure how you get the idea that the J-31 is bleeding edge technolgy - because it does look like a twin engine version of the F-35?
The prototypes lack any outstanding features of the J-20 like EOTS or DAS counterparts.

I do have the impression the J-31 is supposed to be step down technologywise while being cheaper than the J-20. Take the J-31 airframe, put two upgraded WS-13 engines, a state-of-the art AESA radar and you do have a powerful and upgradable 5gen workhorse and/or export aircraft.

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Sorry but that's a lame argument !

By that logic also both older J-20's '2001' & '2002' were a step down technologywise and cheaper. I would be interested if You know the cost of both types ... and do we know if also the J-31 can carry a radar in prototype form, maybe with the rumoured second one ? It also lacks - at least official blessing and therefore it is not surprising, that it is not up to the edge of the J-20. And regarding the upgraded WS-13, not even the serial FC-1s / JF-17s are using them

By the way, it is still the first prototype ... as such don't compare '31001' with '2011' !

Deino

Pmichael said:

I'm not sure how you get the idea that the J-31 is bleeding edge technolgy - because it does look like a twin engine version of the F-35?
The prototypes lack any outstanding features of the J-20 like EOTS or DAS counterparts.

I do have the impression the J-31 is supposed to be step down technologywise while being cheaper than the J-20. Take the J-31 airframe, put two upgraded WS-13 engines, a state-of-the art AESA radar and you do have a powerful and upgradable 5gen workhorse and/or export aircraft.

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I think what he is talking about is bleeding edge for China. Sure, J-31 looks like F-35, but it's not like SAC expects to get any help or can subcontract American companies to produce any subsystems. SAC would have to find domestic partners for all the subsystems on the J-31. Since china has not developed a mature gen-5 fighter infrastructure, this would be bleeding edge for China. I think that's what he meant.

Oh BTW, develop of a 5th gen fighter sounds so easy to you. "Just put something together. Boom! You get a 5th gen fighter". If it was that easy, everyone would have done it. It is a complex and sophisticated and needs highly coordinated effort from multiple institutions and decades of hard work.

Well, "easy" is an relative term in aerospace engineering.

But there are more and less complex projects. And looking at the flying prototypes and the comments of people involved, there is nothing that could imply that the J-31 is supposed to be on the same level as the J-20.

Pmichael said:

Well, "easy" is an relative term in aerospace engineering.

But there are more and less complex projects. And looking at the flying prototypes and the comments of people involved, there is nothing that could imply that the J-31 is supposed to be on the same level as the J-20.

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But that does not say J-31 is easy. Both are highly complex systems, with the J-31 slightly less complex than the J-20. On a scale of easiness, both would be on the difficult end of the spectrum with the J-31 displaying a slight blue shift. But it, by no means, suggests that it is easy. We are not in a binary world, where everything can be categorized as easy or difficult.

vesicles said:

But that does not say J-31 is easy. Both are highly complex systems, with the J-31 slightly less complex than the J-20. On a scale of easiness, both would be on the difficult end of the spectrum with the J-31 displaying a slight blue shift. But it, by no means, suggests that it is easy. We are not in a binary world, where everything can be categorized as easy or difficult.

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I didn't use the term "easy" in my original post.

I said that China could put a capable but less expensive 5gen aircraft with using technolgies which are already in the pipeline. The PLAN also denied that the J-31 is planned as future carrier-capable aircraft, so there is not really a place for another technolgy monster.

Perhaps the J-31 and J-20 shares subsystems and component technologies to lower costs, that's a possibility. Given China's mix and match approach it may have wanted to imitate the US hi-lo F-15 & F-16 pairing for 4th gen aircraft J-11 & J-10, but imitate the Soviet hi-lo Su-27 & Mig-29 pairing for 5th gen aircraft J-20 & J-31. A contributing factor may be that China wants only domestic engines in 5th gen aircraft and they are cautious enough about their domestic engine reliability to mandate twin engine designs. It may also be recognition that a single domestic engine would not be able to provide enough thrust to meet performance requirements. China treats a lot of military technology development as if they are the US skunkworks, including whether the Varyag was going to be refurbished. Voila the Liaoning! So it is still very much a possibility that the J-31 may be intended as a carrier aircraft.