Shenyang FC-31 / J-31 Fighter Demonstrator

Air Force Brat said:

that's the beauty of the 5th Gen

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There are two main beauties of the 5th generation: true (shape)stealth and supercruise with meaningful combat load.
All others(mainly electronical)can be implemented in 4th gen aircraft just as well, say, F/A-18E.
Furthermore, if 5th gen for one reason or another hasn't calculated something in - it will weight on it's shoulders much harder than 4th gen.

Say, meteor.

Gloire_bb said:

There are two main beauties of the 5th generation: true (shape)stealth and supercruise with meaningful combat load.
All others(mainly electronical)can be implemented in 4th gen aircraft just as well, say, F/A-18E.
Furthermore, if 5th gen for one reason or another hasn't calculated something in - it will weight on it's shoulders much harder than 4th gen.

Say, meteor.

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Well, I'm gonna disagree, number one, it depends on which 5 Gen we are talking about,, (J-20 likely does NOT supercruise) so are you saying you don't like the J-20? I'm sure FC-31 does NOT supercruise either, however both do appear to have good RCS reduction shaping?

moreover, in order to incorporate the 5 Gen avionics of the F-35 into a 4 Gen, its highly unlikely that would go smoothly, the F-35 and likely the FC-31 were/will be designed around their 5 Gen avionics packages, those particular avionics require a GREAT DEAL of integration with the airframe itself in order to function, the same is true of the J-20, and that would prohibit effective integration of those same avionics into the J-15, J-16, or any other Flanker derivative for that matter, starting with EOTAS and working your way around the aircraft,,, that's just a lot more that you have imagined..

Even powering up the system, getting all those electronics and bus bars and circuit breakers, and switch panels, and heat sinks,,,, I mean really, you have no idea, radar, IRST, cooling, heating, fire fighting,,, even 4th Gens are loaded already with electrical equipment,,, not even considering sensors and sensor fusion???

It is highly unlikely that J-20 cannot supercruise with WS15. Even if we assume they haven't worked in any miracle weight saving techniques and it's weight is commensurate with F-22's, with WS15, it has a thrust to weight likely matching F-22 assuming WS15 will indeed achieve a minimum of 180KN. Even Rafale and Typhoon can supercruise with small external loads. J-20 load in stealth mode is not greater than that. It will have equal if not greater thrust to weight (depends on weight reductions) and it will have less drag and more lift from the fuselage (thanks Lockheed Martin). Every indicator points to J-20 being able to supercruise at least as well as typhoon in normal air to air load.

When we talk about 5th gen avionics, there are certainly components that require the fighter to be designed around but many that don't. There's nothing stopping J-15 from receiving a radar as good if not better than J-31. Same applies to IRST, EODAS, electronic warfare etc. J-15 is much larger so it can actually accommodate more if they are willing to sacrifice some fuel space. The benefit of domesticating the flanker is to be able to play around a little with its structure as well. A vintage car can still take a modern engine is there's room for it. Before anyone says this is oversimplifying the analogy, yes but none of you know the specifics on how much they can modify the fighter so your opinion is as unfounded as mine. 4th gen frames can receive avionics upgrades that come close to matching those on 5th gens. The main problems would be legacy structural limitations and space so there's a good chance 5th gens do carry more sophisticated electronics but only so because they were designed around them. How big this margin is is completely unknown at this point. But we do know there are no such problems with radar and conventional sensors. Sensor fusion is sophisticated software. Hardly impossible for 4th gen to match 5th gen in. The main advantage of 5th gens if (yes if again) 4th gens can be upgraded to this level, is their LO (at the price of payload and sometimes range not to mention cost and complexity). This ability will deteriorate in coming decades. How quickly and by how much remains to be seen.

I should mention WS15's 180KN is afterburner of course, which means that doesn't count for supercruise but it reveals the thrust the engine is capable of. Remember the goal is >190KN afterburner. The only parameter i doubt re J-20's supercruise is the engine thrust. I doubt WS10 can do it. Aerodynamically I think the Chinese engineers can build something that supercruises given the experience with supersonic and hypersonic aircrafts and wind tunnels they've been playing with for so long. WS15 even if weaker than ideal, still gives J-20 a likely higher T2W than typhoon and rafale. That's assuming no weight reduction. If 15T news is indeed true, then sky's the limit. Also remember the drag and lift factors, pushing it even further into the can supercruise territory. WS13 or RDxx J-31 is another story. WS19 is a ghost at the moment.

ougoah said:

I should mention WS15's 180KN is afterburner of course, which means that doesn't count for supercruise but it reveals the thrust the engine is capable of. Remember the goal is >190KN afterburner. The only parameter i doubt re J-20's supercruise is the engine thrust. I doubt WS10 can do it. Aerodynamically I think the Chinese engineers can build something that supercruises given the experience with supersonic and hypersonic aircrafts and wind tunnels they've been playing with for so long. WS15 even if weaker than ideal, still gives J-20 a likely higher T2W than typhoon and rafale. That's assuming no weight reduction. If 15T news is indeed true, then sky's the limit. Also remember the drag and lift factors, pushing it even further into the can supercruise territory. WS13 or RDxx J-31 is another story. WS19 is a ghost at the moment.

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We don’t know how accurate those figures are.

We don't but we expect better thrust than the most powerful WS-10. We don't know anything so why would brat claim J-20 probably doesn't supercruise. I'm giving reasons to indicate otherwise. These figures are already conservative estimates.

Supercruise, at least to my limited knowledge, is more of a function of the airframe's aerodynamic profile (i.e. lower drag coefficient) than raw engine thrust, the latter of which is more important in acceleration rather than the maintenance of speed.

ougoah said:

We don't but we expect better thrust than the most powerful WS-10. We don't know anything so why would brat claim J-20 probably doesn't supercruise. I'm giving reasons to indicate otherwise. These figures are already conservative estimates.

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Brat was claiming that J-20 likely cannot supercruise in its given state with WS-10 or AL-31X. He was not saying that it did not have the potential to do so with WS-15. I think we all agree that J-20 was designed to supercruise with WS-15. Only question is whether J-20 could attain limited supercruise with its current engines. For reference, F-22 supercruises at mach 1.8 with engines that give 120kN in dry thrust, though with squint nozzles, I don't know how much that amounts to. Early AL-31 has dry thrust of 74.5kN and AL-41 has 86.3kN while early WS-10X was reported to have 89kN (possiby due to it being derived from a civilian engine). So whether J-20's current engines could pop it to over mach 1 in its current weight is uncertain, though for practical purposes, mach 0.99 or getting in just under breaking the sound barrier is not much worse than very low supercruise.

SinoSoldier said:

Supercruise, at least to my limited knowledge, is more of a function of the airframe's aerodynamic profile (i.e. lower drag coefficient) than raw engine thrust, the latter of which is more important in acceleration rather than the maintenance of speed.

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It's really both in combination. If your frame was less optimized for supercruise, you can supplement it with extra engine power and if you lacked engine power, you could design a frame more around supercruise. Flanker frames couldn't supercruise until the Russians pumped extra juice into the Su-35 with the AL-41 and now it can.

Can J-31 carry anti-shipping missiles internally? I'd like to see a source. Which missiles? What it their range and payload?

manqiangrexue said:

It's really both in combination. If your frame was less optimized for supercruise, you can supplement it with extra engine power and if you lacked engine power, you could design a frame more around supercruise. Flanker frames couldn't supercruise until the Russians pumped extra juice into the Su-35 with the AL-41 and now it can.

Can J-31 carry anti-shipping missiles internally? I'd like to see a source. Which missiles? What it their range and payload?

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Yes, it's a combination of both airframe design and sustained engine thrust, but the quality itself is more of a testament to the TWR and aerodynamic performance rather than too useful of a capability.

Images presented at the FC-31 booth during the Zhuhai airshow confirmed that it could carry four 500 kg weapons or four supersonic ASMs in its bay; these weapons could be easily substituted with AShMs of similar size and weight.

SinoSoldier said:

Yes, it's a combination of both airframe design and sustained engine thrust, but the quality itself is more of a testament to the TWR and aerodynamic performance rather than too useful of a capability.

Images presented at the FC-31 booth during the Zhuhai airshow confirmed that it could carry four 500 kg weapons or four supersonic ASMs in its bay; these weapons could be easily substituted with AShMs of similar size and weight.

View attachment 44728

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Do you know of any Chinese anti-shipping missiles that are 500kg or less and within the given length of the bomb bay? If so, what is the range and how much damage is it mean to do (sink a 2,000 ton ship, a 4,000 ton ship, etc...)? Because I think that's too small for a powerful anti-ship missile; maybe they meant air-to-surface for killing tanks, radars, SAMs, etc... For reference, YJ-12 (launched by J-16 and JH-7) is 2,500kg, 6.3 meters with 400km range for killing 5,000 ton ships.