Chinese Engine Development


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Captain
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The J-20 LRIP variants used AL-41F-M2 variants (?) with around 14000 kgf thrust ( I'm going with the conservative AL-41F-1S for a ballpark figure
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).But since WS-10 series has made an appearance on J-20, are you thinking that they went with an engine with alower Thrust or equal Thrust to the imported russian engine? What was the pressing concern that forced them to fix a WS-10 series engine on the J-20? Unless there has been some improvements in reliability or thrust perhaps ?
Dieno corrected me by putting a thrust range of 128 to 145 kN ! for the WS-10 series. I am in no position to cross him ( or you ftm). Let's just leave the thrust numbers as it is . I do want to add accurate thrust numbers though.

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I think the AL-41F-M2 was Deino's hypothesis (He owns the patent :p). Another one was that the J-20 LRIP used AL-31F modified locally (In China). For CAC to quickly move away from AL-31F to WS-10 suggest some serious reliability issue with the older engine. It shows how far the WS-10 has come from the problems it faced in the mid-2000s. The loss of some thrust in afterburner may be acceptible if reliability is much better. And remember, when it comes to supercruise, what is important is the dry-thrust. We don't know the dry-thrust of the WS-10. AL-41F1S dry thrust is 86 kN.
 

Xsizor

Junior Member
Registered Member
145 kN is the max thrust value in afterburner for the Salut AL-31FM2 -
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I was talking about the WS-10 series. Dieno marked its thrust as ranging from 128 to 145 kN. This number is very interesting. We are not talking about AL-31 derivatives.If 145 kN is the max thrust, which of the WS-10 series would be the probable engine to achieve that? That was my question. I think it would be WS-10C ( equipped for J-20s with serrated nozzles).
Edit: This would be higher than the 137 kN thrust rating you pointed to earlier.
 
I was talking about the WS-10 series. Dieno marked its thrust as ranging from 128 to 145 kN. This number is very interesting. We are not talking about AL-31 derivatives.If 145 kN is the max thrust, which of the WS-10 series would be the probable engine to achieve that? That was my question. I think it would be WS-10C ( equipped for J-20s with serrated nozzles).
Edit: This would be higher than the 137 kN thrust rating you pointed to earlier.
My reasoning in saying 145kN is because the FM2 is rated there and for the Chinese to swap a 145kN FM2 for a WS-10 variant, that variant probably either has similar wet thrust to 145kN with greater dry thrust, (making the swap worthwhile) or might have even greater wet thrust than 145kN (making the swap worthwhile).

While AL-31 failures have caused J-10 crashes, I don't think they've caused any J-11 crashes. Their reliability, in my opinion, is far from poor enough for that reason to merit an engine swap for a double-engined fighter, much less if the newer engine has significantly reduced performance (such as 8kN less wet thrust per engine). The point is that introducing a second interim engine before the WS-15 is a good deal of work and there has to be something to justify that other than "let's use local even if it has less thrust."
 

Xsizor

Junior Member
Registered Member
My reasoning in saying 145kN is because the FM2 is rated there and for the Chinese to swap a 145kN FM2 for a WS-10 variant, that variant probably either has similar wet thrust to 145kN with greater dry thrust, (making the swap worthwhile) or might have even greater wet thrust than 145kN (making the swap worthwhile).

While AL-31 failures have caused J-10 crashes, I don't think they've caused any J-11 crashes. Their reliability, in my opinion, is far from poor enough for that reason to merit an engine swap for a double-engined fighter, much less if the newer engine has significantly reduced performance (such as 8kN less wet thrust per engine). The point is that introducing a second interim engine before the WS-15 is a good deal of work and there has to be something to justify that other than "let's use local even if it has less thrust."
I wanted someone to say that ! Waiting till more details emerge of the J-20s equipped with WS-10 series. Another is the sight of 4 WS-20s on a Y-20. Thank you for the helpful comments.
 

Tirdent

Junior Member
Registered Member
As I've said before, whatever its thrust rating is, the WS-10 has two non-trivial advantages over the AL-31F:

1) It makes the J-20 fully indigenous.

2) It has stealthy nozzles.

That could easily tip the scales in its favour even at no extra thrust and reliability (that thrust and reliability are now on par we know from the J-10 adopting it).
 
As I've said before, whatever its thrust rating is, the WS-10 has two non-trivial advantages over the AL-31F:

1) It makes the J-20 fully indigenous.

2) It has stealthy nozzles.

That could easily tip the scales in its favour even at no extra thrust and reliability (that thrust and reliability are now on par we know from the J-10 adopting it).
1) At a time when Sino-Russian relations are very good and with the upcoming final domestic engine for J-20, an indigenization effort like this that detracts manpower from other improvements to the J-20 doesn't make sense unless there is some performance gain. From what I know, the CFM civilian origins of the WS-10 give it a good bit higher dry thrust to wet thrust ratio than the AL-31 series. If this is true, and the WS-10 version in the J-20 has reached a competitive wet thrust with the 145kN AL-31FM2 that is most likely in the J-20, then chances are that the Taihang provides a substantial increase dry thrust, aiding supercruise. In my opinion, that would be make the effort more worth it than even some small increase in wet thrust. And to indigenize just to indigenize for no other benefits makes no sense to me at this point for the J-20 project.

2) Nozzles can be changed without swapping the engine for much smaller workload if there was no real reason to swap the engine.
 

Tirdent

Junior Member
Registered Member
1) As far as I know the WS-10 family has a BPR of about 0.8 as opposed to ~0.6 in the AL-31F, meaning its reheated to dry thrust ratio is unlikely to be lower. In other words, unless the version now fitted to the J-20 has significantly higher afterburning thrust than whatever AL-31F variant was originally installed, the WS-10 is probably not going to have more dry thrust. This is possible of course, but would only really be plausible if the old engine was a lower-thrust earlier AL-31FN.

2) Well, apparently not so trivial that it could be done for the initial series production batch with AL-31Fs, despite the obvious RCS drawback.
 

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