Shenyang FC-31 / J-31 Fighter Demonstrator

A few brain bites about the never-ending J-20 vs FC-31 carrier jet discussion:

• J-20 should have a combat radius of ~1500 km (using F-22 as reference)
• FC-31 (v1) has a combat radius of 1250 km
• An enlarged FC-31 should have a combat radius approaching that of the J-20
• The J-20 is roughly comparable to the J-15 in size

My $0.02 on the FC-31's prospects on being developed into a naval carrier-based jet:

• Smaller footprint: allows carriers to carry more aircraft and offering greater tactical flexibility
• Front landing gears have twin wheels which are suggestive of its intention as a potential navalized design
• SAC has far more experience than CAC at developing naval aircraft -- in fact, some suspect that the J-15T is a tech demonstrator for a future SAC naval jet
• A 2013 visit by the Chinese president to the FC-31 production plant is highly suggestive of its approval to become a future PLAN fighter (according to online opinion)
• An enlarged FC-31 should effectively close the range gap between the FC-31 and J-20 designs
• Former official models of the FC-31 shows it being potentially armed with YJ-83K AShM and YJ-91, all naval weaponry

With the decision to construct the Type 002(003?) carrier and the induction of J-20H land-based naval fighters in the future, it is clear that the PLAN has already decided between the J-20 and FC-31 for its next-generation carrier aircraft. Continued testing of the FC-31V2, along with rumors and "hints" of a V3 under development, it is likely that the FC-31 could be the next-gen carrier jet at this point.

But, as usual, wait and see. Sun Cong stated in 2013 that he expects the next-gen naval fighter to appear no later than 2020, so we might not have to wait for long.

SinoSoldier said:

A few brain bites about the never-ending J-20 vs FC-31 carrier jet discussion:

• J-20 should have a combat radius of ~1500 km (using F-22 as reference)
• FC-31 (v1) has a combat radius of 1250 km

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These numbers are meaningless, particularly in relation to each other. Any combat radius figure relies on a number of assumptions (transit profile, combat assumptions, payload, reserves) that cannot be assumed to hold between two different figures. And using F-22 as a reference for J-20 is unwise in the first place.

An enlarged FC-31 should have a combat radius approaching that of the J-20

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Maybe, but how would that work? If you enlarge the aircraft without improving/changing the engine then you are degrading performance to achieve increased range, probably in similar ways to F-35C vs. F-35A. And if you wanted to maximise range in an aircraft of a given size the plane would have a single engine with higher bypass ratio, like F-35. And if you want to make the plane larger without degrading performance you have to use a larger engine (WS-10 or -15 base) which puts it in the same category as J-15/J-20.

But, as usual, wait and see. Sun Cong stated in 2013 that he expects the next-gen naval fighter to appear no later than 2020, so we might not have to wait for long.

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I for one hope that PLAN's future carrier-based aircraft is not based on J-31 as that will place China behind the curve from day #1 (an F-35C but 10+ years later...) and give future US platforms a decisive advantage.

The exception to this is if China plans two naval combat aircraft projects: J-31 as a near-term solution to complement J-15, and then a longer-term solution to replace J-15 and take on US 6th gen aircraft.

Lethe said:

These numbers are meaningless, particularly in relation to each other. Any combat radius figure relies on a number of assumptions (transit profile, combat assumptions, payload, reserves) that cannot be assumed to hold between two different figures. And using F-22 as a reference for J-20 is unwise in the first place.

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I had always thought that reported combat radii are based on a clean profile (i.e. no external weaponry or tanks) and on a full fuel load. The numbers illustrate that the potential difference between the combat radii of the J-20 and FC-31 may not be an insurmountable challenge for the latter or for the PLANAF to deal with.

Lethe said:

Maybe, but how would that work? If you enlarge the aircraft without improving/changing the engine then you are degrading performance to achieve increased range, probably in similar ways to F-35C vs. F-35A. And if you wanted to maximise range in an aircraft of a given size the plane would have a single engine with higher bypass ratio, like F-35. And if you want to make the plane larger without degrading performance you have to use a larger engine (WS-10 or -15 base) which puts it in the same category as J-15/J-20.

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Why would you think that enlarging the FC-31 would decrease its kinematic performance to an unacceptable level? Do we have existing data on roll rate, climb/turn rates, high/low altitude performance, etc., to comment on this? Additionally the FC-31 is slated to receive more powerful WS-19 turbofan engines in the coming years.

Has the Super Hornet been "downgraded" in performance relative to the F/A-18C because it didn't adopt F110/F100-class engines?

Lethe said:

I for one hope that PLAN's future carrier-based aircraft is not based on J-31 as that will place China behind the curve from day #1 (an F-35C but 10+ years later...) and give future US platforms a decisive advantage.

The exception to this is if China plans two naval combat aircraft projects: J-31 as a near-term solution to complement J-15, and then a longer-term solution to replace J-15 and take on US 6th gen aircraft.

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A sixth generation project is a different story and frankly one that will take much longer to manifest. At the current stage, the competition is between the FC-31 and J-20, and nothing suggests that the former will put the PLANAF behind the curve any more than the latter will.

Funnily, I strongly believe that the J-15 should be axed as soon as the airwing for the 001A (or 002 as some people call it) is completed.

SinoSoldier said:

I had always thought that reported combat radii are based on a clean profile (i.e. no external weaponry or tanks) and on a full fuel load.

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It might be, or it might not be. A "combat radius" for a mission that involves hauling 6 tons of bombs at low-altitude with afterburner into and out of the target area and fifteen minute reserves is going to be much lower than a "combat radius" for a mission involving high-altitude cruise carrying 1 ton of AAMs with no afterburner use and no reserve margin. There are just too many variables to compare 'combat radius' figures for different aircraft from different sources.

Why would you think that enlarging the FC-31 would decrease its kinematic performance to an unacceptable level? Do we have existing data on roll rate, climb/turn rates, high/low altitude performance, etc., to comment on this?

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I don't know that, but consider that there is a reason why the aircraft is the way it is in the first place. Now, maybe the assumptions made by the manufacturer are wrong, and the customer actually places a greater emphasis on a certain characteristic (in this case range) than the designers anticipated, and are willing to accept compromises in other areas to get it. But nonetheless, J-31 in its initial form was the manufacturer's best attempt at balancing what it felt were the required characteristics.

In any case, if we are talking about a relatively small "enlargement" then I expect we are looking at something similar to the F-35A --> F-35C transition, i.e. enlarged wing carrying more fuel and with better low-speed handling characteristics suited to carrier landings.

Has the Super Hornet been "downgraded" in performance relative to the F/A-18C because it didn't adopt F110/F100-class engines?

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Super Hornet received +30% thrust from the switch from F404 to F414 engines. But nonetheless, yes, its performance has been downgraded relative to F/A-18C. Super Hornet is one of the slowest and least agile fighters built since the 1960s. Like MiG-29SMT or MiG-29M, Super Hornet illustrates the trade-offs required to increase the range of an existing design.

At the current stage, the competition is between the FC-31 and J-20, and nothing suggests that the former will put the PLANAF behind the curve any more than the latter will.

Funnily, I strongly believe that the J-15 should be axed as soon as the airwing for the 001A (or 002 as some people call it) is completed

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The basic characteristics of J-20 as a larger airframe mean that it has greater growth potential to adapt to the challenges posed by future adversaries: it has longer legs, probably better speed and agility, more powerful sensors, and greater volume and power to accommodate future developments such as DEW. A future "J-20D" could be competitive with US 6th gen in a way that J-31 never could be.

This is the inverse of the relationship between J-15 and Super Hornet. A mature, catapult-capable J-15 will thoroughly outclass Super Hornet in every relevant aspect: speed, agility, sensors, payload. There is nothing Super Hornet can do to close the gap for the simple reason that is a smaller aircraft with a compromised aerodynamic design.

The basic characteristics of the airframe/powerplant determine the platform's performance potential. J-20 has greater potential than J-31, just as J-15 has greater potential than Super Hornet. Going forward with J-31 as the PLAN's sole future carrier-based combat aircraft would be condemn China's carrier air wings to "second best" status for the next generation.

SinoSoldier said:

A few brain bites about the never-ending J-20 vs FC-31 carrier jet discussion:

• J-20 should have a combat radius of ~1500 km (using F-22 as reference)
• FC-31 (v1) has a combat radius of 1250 km
• An enlarged FC-31 should have a combat radius approaching that of the J-20
• The J-20 is roughly comparable to the J-15 in size

My $0.02 on the FC-31's prospects on being developed into a naval carrier-based jet:

• Smaller footprint: allows carriers to carry more aircraft and offering greater tactical flexibility
• Front landing gears have twin wheels which are suggestive of its intention as a potential navalized design
• SAC has far more experience than CAC at developing naval aircraft -- in fact, some suspect that the J-15T is a tech demonstrator for a future SAC naval jet
• A 2013 visit by the Chinese president to the FC-31 production plant is highly suggestive of its approval to become a future PLAN fighter (according to online opinion)
• An enlarged FC-31 should effectively close the range gap between the FC-31 and J-20 designs
• Former official models of the FC-31 shows it being potentially armed with YJ-83K AShM and YJ-91, all naval weaponry

With the decision to construct the Type 002(003?) carrier and the induction of J-20H land-based naval fighters in the future, it is clear that the PLAN has already decided between the J-20 and FC-31 for its next-generation carrier aircraft. Continued testing of the FC-31V2, along with rumors and "hints" of a V3 under development, it is likely that the FC-31 could be the next-gen carrier jet at this point.

But, as usual, wait and see. Sun Cong stated in 2013 that he expects the next-gen naval fighter to appear no later than 2020, so we might not have to wait for long.

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This has already been debated to death regarding the pros and cons of J-20 vs an FC-31 derived design, however there are a few other new points you bring up which I'd like to address.

SAC has far more experience than CAC at developing naval aircraft -- in fact, some suspect that the J-15T is a tech demonstrator for a future SAC naval jet

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Yes, it is true that SAC obviously has more experience in developing naval aircraft given J-15 is from SAC... however I'm pretty sure the J-15T (or whatever we want to call it) is seen as a demonstrator for a production model J-15 catapult compatible variant.

Obviously any experience gained in developing a catapult compatible J-15 variant will be useful in developing a future catapult compatible 5th generation fighter, but let's not tease the idea that the primary accepted purpose of J-15T is for a production catapult compatible variant.

A 2013 visit by the Chinese president to the FC-31 production plant is highly suggestive of its approval to become a future PLAN fighter (according to online opinion)

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That literally means nothing for the topic we're interested in.
If mere association to the Chinese political leadership is meant to reflect how likely it is for FC-31 or J-20 to become the Navy's new carrierborne fighter, then the fact that J-20 made a high public flyover at the parade at Zhurihe which Xi presided over would be an even bigger sign.

There were zero indications that Xi's visit to SAC and inspection of the FC-31 is related to its likelihood of being the future carrierborne fighter. I'm not sure which online opinions are making that connection, but I see no basis to think it is logical.

Also, "FC-31 production plant"??? FC-31 is not in production. There is no dedicated FC-31 production line, at best FC-31 was produced at the same SAC facility where they produce the rest of their aircraft.

Former official models of the FC-31 shows it being potentially armed with YJ-83K AShM and YJ-91, all naval weaponry

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"Official" models often don't mean anything about whether a particular platform or product is going to eventuate or not.

We had "official" models this year of a supercarrier with UCAVs, AEW& and carrierborne J-20s aboard, that does not mean J-20 will be the next carrierborne fighter.


And no, YJ-83K and YJ-91 are not "all naval weaponry". Land based fighter and strike aircraft field those weapons in their various variants as well.




There is a reasonable case to argue that FC-31 or a derivative remains in the running for the future carrierborne fighter, but there's no reason to use additional weak premises to suggest that FC-31 is somehow more suggested to be the final choice than a naval J-20 is.


Finally I do not see any reason to think that the Navy has already made a decision for its future carrierborne fighter. It is perfectly reasonable to think the Navy's commitment to build the 003 (ex-002) can be made at this time without yet settling on a fighter choice for its complement. If anything, the decision to build the carrier could logically precede the decision for the fighter choice, as it should be the carrier that dictates the requirements and parameters of the aircraft that will inhabit it, not the other way around.

siegecrossbow said:

Has the Iranian jet ever flown?

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I haven't seen a vid showing that gizmo in flight

[QUOTE="Bltizo, post: 480604



Yes, it is true that SAC obviously has more experience in developing naval aircraft given J-15 is from SAC... however I'm pretty sure the J-15T (or whatever we want to call it) is seen as a demonstrator for a production model J-15 catapult compatible variant.

We had "official" models this year of a supercarrier with UCAVs, AEW& and carrierborne J-20s aboard, that does not mean J-20 will be the next carrierborne fighter.


And no, YJ-83K and YJ-91 are not "all naval weaponry". Land based fighter and strike aircraft field those weapons in their various variants as well.




There is a reasonable case to argue that FC-31 or a derivative remains in the running for the future carrierborne fighter, but there's no reason to use additional weak premises to suggest that FC-31 is somehow more suggested to be the final choice than a naval J-20 is.


Finally I do not see any reason to think that the Navy has already made a decision for its future carrierborne fighter. It is perfectly reasonable to think the Navy's commitment to build the 003 (ex-002) can be made at this time without yet settling on a fighter choice for its complement. If anything, the decision to build the carrier could logically precede the decision for the fighter choice, as it should be the carrier that dictates the requirements and parameters of the aircraft that will inhabit it, not the other way around.[/QUOTE]

I'm rather certain that the PLANAF will indeed lead the J-15T as China's first CATOBAR fighter, and the FC-31 is perfectly positioned to be its follow on L/O fighter aircraft. yes SAC's experience with carrier based fighters will rule heavily in its favor.

In my opinion, the PLAN is still waiting for their dream 5th gen fighter and has not made a decision yet.

The slow pace of the FC-31 suggests that the PLAN still doesn't like it. Just look at how they are pouring funds and manpower into projects that they are confident about. They are building 4(?) Type-55's at the same time. And they are spitting out new frigates and destroyers like laying eggs. Yet, the FC-31 is moving slower than snails.

I don't think the PLA has any interest in the FC-31. Comparing its development with how they develop other new fighters. To me, the only explanation for this lack of activity would be lack of interest from the PLA.

Air Force Brat said:

I'm rather certain that the PLANAF will indeed lead the J-15T as China's first CATOBAR fighter, and the FC-31 is perfectly positioned to be its follow on L/O fighter aircraft. yes SAC's experience with carrier based fighters will rule heavily in its favor.

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Not as heavily as you may believe.

For the J-10 project, SAC had far greater experience with indigenous fighter development compared to CAC and yet they lost. Before the initiation of the J-10 project, the J-8 project was run from start to finish by SAC while CAC got the leftovers with the J-7 exports.

For the J-20 project, SAC, again, had far greater experience with heavy twin-engine fighters given their production and self-development of Flankers while CAC had only developed single-engine J-10s and JF-17s. And yet SAC still lost.

Needless to say, the PLAAF puts far more emphasis on design merits than institute experience.

vesicles said:

In my opinion, the PLAN is still waiting for their dream 5th gen fighter and has not made a decision yet.

The slow pace of the FC-31 suggests that the PLAN still doesn't like it. Just look at how they are pouring funds and manpower into projects that they are confident about. They are building 4(?) Type-55's at the same time. And they are spitting out new frigates and destroyers like laying eggs. Yet, the FC-31 is moving slower than snails.

I don't think the PLA has any interest in the FC-31. Comparing its development with how they develop other new fighters. To me, the only explanation for this lack of activity would be lack of interest from the PLA.

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PLANAF must have a hearty appetite now considering that they saved the JH-7 program by eating food thrown out by PLAAF. Now not even a medium-weight fifth gen fighter is good enough for them.