J-20 5th Gen Fighter Thread VI

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It could make some sense in the context of the WS-15. If you expect the engine to arrive in 5-10 years (numbers not accurate, just an example), and a normal WS-10 has a lifespan of 15 years. I makes some sense to run it hard enough to lower its lifespan to 10 years since a new engine will be available at that time. There's also another case you haven't considered: the WS-10 has better reliability and easier maintainability than the AL-31F. Or it's simply cheaper.


Are there engine's of the WS-10's generation that have that kind of performance? That's starting to touch F-119 territory.

We have to keep in mind that it's a long and labor-intensive task to integrate a new engine into a jet. The advantages gained have to be worth that. We don't know of any outstanding reliability issue with AL-31 so even if the WS-10 were more reliable, it wouldn't be by much, especially on a twin-engined fighter. Easier maintainability is something we've never heard of and being cheaper, while an advantage, it is not what the PLAAF cares about most and they would certainly not sacrifice performance for any of these 3 benefits. As a matter of fact, even if performance is not sacrificed, I still don't think that these small things are quite enough to merit the trouble of testing yet another interim engine. The only thing that would justify it to me, is if the new WS-10X had considerably greater performance than the AL-31FM2.

And the 155kN WS-10G is just as I said, long rumored but never substantiated.

 

[Inst]

Please Inst ... stop this again and again opening up old issues. It is annoying and must stop.

Take this as a warning

I think others have complained that this forum, despite the views of its members, have veered into Fanboy territory. I stick to my heterodox views relative to this forum; the J-20 is too clunky to be a truly breakout Chinese fighter, whatever others may think (ventral fins, canards etc in a stealth configuration, both not deadly, but unwanted)..

As for the IPE / WS-10X engine, it's possible that the IPE / WS-10X is mainly a reliability improvement on the J-20. The Chinese have made breakthroughs with rhenium blades recently, and a main contest between Western and Chinese/Russian engines has been a question of lifespan and durability. The Chinese have been intensifying training of late, meaning that Western-style fighter engines with high service life is more necessary. On the other hand, the WS-15 could be heavily overclocked to reach 170-180kN, and the WS-15 might not be able to sustain the same lifespans as reliability-improved WS-10. We do know, however, that the WS-15 seems to be a low temperature engine (good for IR stealth), so that the WS-15 might also have service life improvements.

 

[Inst]

We have to keep in mind that it's a long and labor-intensive task to integrate a new engine into a jet. The advantages gained have to be worth that. We don't know of any outstanding reliability issue with AL-31 so even if the WS-10 were more reliable, it wouldn't be by much, especially on a twin-engined fighter. Easier maintainability is something we've never heard of and being cheaper, while an advantage, it is not what the PLAAF cares about most and they would certainly not sacrifice performance for any of these 3 benefits. As a matter of fact, even if performance is not sacrificed, I still don't think that these small things are quite enough to merit the trouble of testing yet another interim engine. The only thing that would justify it to me, is if the new WS-10X had considerably greater performance than the AL-31FM2.

And the 155kN WS-10G is just as I said, long rumored but never substantiated.

I don't actually recall the details of the WS-10 evolution post, wherein the WS-10 was described in numerous variants, with the initial variant being thrust-reduced except under emergency power to compensate for poor reliability. Still, the main advantage of the WS-10 is that it's a domestic Chinese engine and that engine production can be controlled by the Chinese, instead of being dependent on Russian imports.

The other thing is that the WS-10X could be designed specifically for the J-20's intakes; a problem with the F-14, for instance, is that it had fixed inlets and that the additional max thrust of the F110 engines wasn't usable at high velocities. If we assume the J-20's strong max-speed indicates supercruising out the bat (and, if we're going to use the Song Weicong documents, that's a priority of the J-20 design, to supercruise while having engine inferiority), the WS-10X might be a modified version of the WS-10B more adapted to the intake and flight regimes of the J-20.

 

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I don't actually recall the details of the WS-10 evolution post, wherein the WS-10 was described in numerous variants, with the initial variant being thrust-reduced except under emergency power to compensate for poor reliability. Still, the main advantage of the WS-10 is that it's a domestic Chinese engine and that engine production can be controlled by the Chinese, instead of being dependent on Russian imports.

The other thing is that the WS-10X could be designed specifically for the J-20's intakes; a problem with the F-14, for instance, is that it had fixed inlets and that the additional max thrust of the F110 engines wasn't usable at high velocities. If we assume the J-20's strong max-speed indicates supercruising out the bat (and, if we're going to use the Song Weicong documents, that's a priority of the J-20 design, to supercruise while having engine inferiority), the WS-10X might be a modified version of the WS-10B more adapted to the intake and flight regimes of the J-20.

I don't think so. To the best of my knowledge, engines just suck air and give thrust. The intakes can be optimized for the engines, but engines aren't optimized for intake. Even if it's possible to optimize the engine to the intake, the engine is the most complicated piece on a fighter jet while the intake is one of the least complicated so if you had to work on one, you wouldn't choose to change the former to adapt to the latter.

 

[Hyperwarp]

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Maybe there is another version of the WS-10 that exceeds 14,000 kgf (137.3 kN) that the PLAAF has not cleared for the general public. So, unfortunately (for us fanboys) the only thrust values released is the one given below. Don't forget, the 137 kN is in afterburner. Maybe it has better dry thrust compared to others and gives the J-20 better supercruise capability than the AL-31 currently in use.

@Interstellar, can you give us thrust figures of the WS-10 series from the basic variant to the WS-10IPE? Thanks in advance.

PS: despite having good relations with Russian now, the J-20 and even more so, the J-10 going WS-10 is a tremendous milestone for China.

From Zhuhai 2014:

 

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Maybe there is another version of the WS-10 that exceeds 14,000 kgf (137.3 kN) that the PLAAF has not cleared for the general public. So, unfortunately (for us fanboys) the only thrust values released is the one given below. Don't forget, the 137 kN is in afterburner. Maybe it has better dry thrust compared to others and gives the J-20 better supercruise capability than the AL-31 currently in use.

@Interstellar, can you give us thrust figures of the WS-10 series from the basic variant to the WS-10IPE? Thanks in advance.

PS: despite having good relations with Russian now, the J-20 and even more so, the J-10 going WS-10 is a tremendous milestone for China.

From Zhuhai 2014:

I've already considered that in my earlier post and it did seem that since the Taihang was derived from a civilian engine, it has higher dry to wet thrust ratio. I recall seeing 89kN somewhere before for an early WS-10 whereas it is 74.5kN for AL-31F. I question is if it's worth the effort to re-engine a jet design for.

Look to the engine thread. Someone is claiming that WS-10B, C, and D are all going into production this year and I've never heard of C or D. Was hoping to get help from anyone if they knew anything about those.

 

[Deino]

Another minor update in an own issue; I have my first report for Jane's (JDW) published.

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[Inst]

D might simply refer to a TVC version. C should be IPE or so.

As for the engine mods, part of it is that engines are designed to function under various airflow regimes, partially created by the airframe, partially created by the intake. As mentioned under another thread, at altitude and speed, an engine's dry thrust can drop to half due to airflow issues. One possibility is that the WS-10C or D is designed to function better under supersonic regimes at altitude, possibly sacrificing subsonic performance to achieve such. The J-20, after all, is intended as a supercruising aircraft. Given that we see it's Mach 2.3-2.5 capable under afterburner, it's mainly the engine performance that functions as the limiter for Mach 1.5 or Mach 1.8 supercruise.

 

[Hendrik_2000]

via Henri K blog
One of the furtive coatings used by the Chinese fighter J-20

 

[Tirdent]

Whatever else this new WS-10 version brings to the table that we don't have specifics about, it is known for certain to have two significant advantages over the incumbent AL-31F (whichever variant that is):

1) It is fully indigenous, providing complete independence from Russian suppliers.
2) Perhaps more importantly in fact, it has a stealthy (or at least stealthier) nozzle.

Both, as stated, are non-trivial in their own right - so much so that performing "in the ball park" with respect to other measures like thrust and reliability is probably sufficient for these benefits to tip the scales in favour of the new engine. I'm also a bit sceptical that the previous AL-31 in the J-20 is the 140+kN FM3, that engine is a AL-31F pretty much in name only, replacing the entire compressor end (3+6 stages instead of 4+9) and HPT IIRC. I doubt such a major, expensive upgrade would be developed to maturity for just a handful of sales as an interim solution for a non-Russian fighter.

Consider also that the Izd. 117S or F110-GE132 provide a pretty good indication of how far you can sensibly push a WS-10-like architecture - 155kN isn't on the cards IMHO. Not when (according to one Chinese post translated here a while ago) the then-current WS-10 delivered TBO and life half as long as the Izd. 117S running at comparable temperatures - that's not a minor difference. In fact, better (and more convincingly demonstrated) durability is probably why Saturn's Izd. 117S was preferred over the AL-31FM3 (which is aerodynamically a more advanced engine) for the Su-35S.