J-20 5th Gen Fighter Thread V

[Blackstone]

Again, quality and performance aren't the only possible reasons. CAC may simply have more experience with the AL-31's supply chain and maintenance process.

And how does any development team gain experience with new components and subsystems? It's not like there isn't enough prototype J-20s to gain experience and expertise, and lack of that lends credence the team had low confidence in WS-10s, not even enough to try some.

 

[SpicySichuan]

Here is my speculations about the J20 engines. The first two batches of production units after 2017 would most likely use AL-31FN (series 3s) for production, as Chengdu Aircraft plant has use the laters' series 1/2 on J-10s for more than a decade. The original AL-31s (for Su-27s) are probably way too under-powered to make the J-20s combat effective. I heavily doubted that the 117s are currently mounted on the J-20s, as all J-20 prototypes lack thrust-vectoring control. As many of you said earlier, an under-powered J-20 could at least out-match Taiwan's F-16s and Japan's F-15s/F-2s, as long as the F-22s don't show up.
Also, only aircrafts made my Shenyang Aircraft company have experience in operating WS-10 series. It is comply more convenient for Chengdu to keep using AL-31FN series 1/2/3, as the Russo-Chinese Relations are likely to remain stable in the short term, giving China enough time to develop WS-15s, while equipping J-20s with AL-31FN series in the meantime.

 

[Blitzo]

Here is my speculations about the J20 engines. The first two batches of production units after 2017 would most likely use AL-31FN (series 3s) for production, as Chengdu Aircraft plant has use the laters' series 1/2 on J-10s for more than a decade. The original AL-31s (for Su-27s) are probably way too under-powered to make the J-20s combat effective. I heavily doubted that the 117s are currently mounted on the J-20s, as all J-20 prototypes lack thrust-vectoring control. As many of you said earlier, an under-powered J-20 could at least out-match Taiwan's F-16s and Japan's F-15s/F-2s, as long as the F-22s don't show up.
Also, only aircrafts made my Shenyang Aircraft company have experience in operating WS-10 series. It is comply more convenient for Chengdu to keep using AL-31FN series 1/2/3, as the Russo-Chinese Relations are likely to remain stable in the short term, giving China enough time to develop WS-15s, while equipping J-20s with AL-31FN series in the meantime.

Yes it is probably unlikely for J-20 to be refit with WS-10s as interim engines, and easier to simply continue with whatever current Al-31 variant they have been using until WS-15 is ready.

It is important to remember that even without WS-15, the J-20 should be able to offer a whole realm of new capabilities to the Chinese Air Force via its potentially very advanced sensor suite and stealth characteristics, in the BVR domain but also more importantly as a force multiplier for non 5th generation aircraft.

Thinking about J-20 only in the context of "out matching" opposing fighter types is probably not the most pragmatic way of considering it, but should rather consider the scope of J-20 when operating within the context of a larger air war and how it can affect the performance and capabilities of all other friendly assets.

 

[Blitzo]

............
So how many slave workers died making this prototype? That "2101" paint job looks like it was smeared on by hand soaked in blood!

I AM JOKING!

Seriously, that paint job is just horrible. Even if its just temporarily.

Nope, I am african american with dwarfism and you just insulted me you racist!
Now I have to go riot and loot..........

Quite frankly I find both of these posts inappropriate verging on deplorable, and not in the spirit of this forum.

 

[Brumby]

It is important to remember that even without WS-15, the J-20 should be able to offer a whole realm of new capabilities to the Chinese Air Force via its potentially very advanced sensor suite and stealth characteristics, in the BVR domain but also more importantly as a force multiplier for non 5th generation aircraft.

The concept of force multiplier in 5th gen assets come from its advanced sensor capabilities and in sharing that situational battlespace information with other legacy air assets. In the case of the J-20, do you know what advanced sensor suite it actually will have? How much facts are actually out there as opposed to speculation?

 

[Blitzo]

The concept of force multiplier in 5th gen assets come from its advanced sensor capabilities and in sharing that situational battlespace information with other legacy air assets. In the case of the J-20, do you know what advanced sensor suite it actually will have? How much facts are actually out there as opposed to speculation?

That is why I said potentially very advanced.

I've written a post on the subject matter of just what kind of sensors J-20 is likely to have, if you are interested.

Please, Log in or Register to view URLs content!

 

[Tyloe]

Again, quality and performance aren't the only possible reasons. CAC may simply have more experience with the AL-31's supply chain and maintenance process. Alternatively, supply constraints, either in the whole product or in parts for the WS-10 could play a factor. It could also be that when the J-20 started testing there were reliability and performance issues with the WS-10, but once the design was committed to another engine switching engines would be impractical at any point during the development process regardless of whether the WS-10 resolved such issues later. Removing as many unknowns as possible is important in a testing environment. Some of those unknowns may be related to reliability and performance concerns, either in the past or present, but many more do not.

My point about the WS-15 is that whether the J-20 uses WS-10s or not tells us nothing about whether the WS-15 will be early, on schedule, or late.

A performance issue seems like a legitimate reason tbh. CAC should have had access to both engines for flight testing prototypes in such an important program. Now that the final prototype and the first LRIP both use al-31s it would imply something is wrong with current WS-10s that justifies going back to Russian turbofans. If reliability is as issue for current WS-10 it means an upgraded version or 'WS-15' is coming later than expected. The final desired engine appearing in the 2020s seems reasonable in this regard.

 

[Blitzo]

A performance issue seems like a legitimate reason tbh. CAC should have had access to both engines for flight testing prototypes in such an important program. Now that the final prototype and the first LRIP both use al-31s it would imply something is wrong with current WS-10s that justifies going back to Russian turbofans. If reliability is as issue for current WS-10 it means an upgraded version or 'WS-15' is coming later than expected. The final desired engine appearing in the 2020s seems reasonable in this regard.

Not necessarily.

You are assuming here that CAC would have reason to replace Al-31s with WS-10s as interim engines because of some nebulous difference in "reliability," and that if WS-10s were as "reliable" as Al-31s supposedly are, then CAC should naturally have sought to replace WS-10s in the stead of Al-31s.

But that ignores the fact that integration of WS-10s (remember, it is a whole different powerplant) in place of Al-31s would incur additional development costs and likely delay the date that the Air Force could receive initial J-20s. More importantly, we must also remember that WS-10s do not have sufficiently high class of thrust to achieve the true kinematic capability J-20 is intended to achieve with WS-15 and it is likely that WS-10 is no more superior (if not a little inferior) in terms of thrust compared to whatever Al-31 variant current J-20s are using.
Therefore, it is unlikely that the Air Force has reason to replace Al-31s with WS-10s on the basis of any performance issues even if we assume both were equally "reliable". Putting it another way, for WS-10s to replace Al-31s on J-20s as interim engines would likely require a substantial degree of superiority in certain domains (such as performance or cost) for the integration of WS-10s to be worth the time and money.

We also need to consider the issue of accessibility. CAC by its history has a good relationship with its powerplant supplier, and it appears they are able to access the necessary engine for interim use in initial J-20s then it has no reason to integrate another engine. If CAC was suddenly cut off from a supply of Al-31s for J-20s then they would probably naturally move towards integrating WS-10s on J-20s as interim engines.

Putting it all together: if CAC or the Air Force really were interested in replacing Al-31s with WS-10s, then there would need to be a significant difference in certain aspects of capability (including performance and/or cost) or accessibility for the replacement to be worthwhile, seeing as they would merely be replacing one interim engine with another.
Therefore, assuming that CAC has not replaced the Al-31s on J-20 with WS-10s as simply being due to "reliability" differences ignores the very likely possibility that CAC and the Air Force probably would not be interested in replacing Al-31s with WS-10s on initial J-20 batches anyway even if WS-10 and Al-31 had similar reliability, due to the fact that both Al-31 and WS-10 have similar performance and are underpowered relative to the aircraft, and both are thus very much interim engines.

 

[latenlazy]

And how does any development team gain experience with new components and subsystems? It's not like there isn't enough prototype J-20s to gain experience and expertise, and lack of that lends credence the team had low confidence in WS-10s, not even enough to try some.

They learn with adoption, but learning an entirely new system with a different engine throws extra unknowns into your testing process, which is pretty pointless when the purpose of testing in this case is the airframe, not the engine. There is literally zero benefit CAC would have gotten from taking on a newer engine with equivalent performance. If the engine were the WS-15 instead it may have been a different matter (risk/reward). Keep in mind they probably would have had to make a decision about which engines to commit to for testing even before 2001 flew. That means their assessment of risk would be with the WS-10 as it was in 2010, not as it is today.

Your argument that they now have enough J-20s to test it with the WS-10 doesn't follow. Why would they bother testing the WS-10 on the J-20 now if even the AL-31 is meant to be an interim solution? That'd just be a waste of testing time and resources.

A performance issue seems like a legitimate reason tbh. CAC should have had access to both engines for flight testing prototypes in such an important program. Now that the final prototype and the first LRIP both use al-31s it would imply something is wrong with current WS-10s that justifies going back to Russian turbofans. If reliability is as issue for current WS-10 it means an upgraded version or 'WS-15' is coming later than expected. The final desired engine appearing in the 2020s seems reasonable in this regard.

Refer to my second paragraph in response to Blackstone.

Also, why would you want to use both engines for the testing process? Especially if neither engine is meant to be the final engine? You'd be throwing an extra variable into the testing process with absolutely *zero* benefits.

The WS-15 isn't an "upgraded" WS-10. It's an entirely different engine. Furthermore, lessons learned earlier are usually not problems experienced later unless you assume incompetence.

 

[davidwangqi]

Actually, there were rumors saying the next phase development of J20 could be the replacement of AL31 with the latest version WS10, considering WS15 won't be ready before 2020. Just like recently revealed J10B/Cs that are powered with WS10, there must be something in WS10 they like over AL31, probably the slightly higher trust/reliability or foreseeable future for upgrading.

Even if the first several production batches will still use Al31, I don't see why they should not built a few testing prototypes powered with WS10s.

Not necessarily.
Therefore, assuming that CAC has not replaced the Al-31s on J-20 with WS-10s as simply being due to "reliability" differences ignores the very likely possibility that CAC and the Air Force probably would not be interested in replacing Al-31s with WS-10s on initial J-20 batches anyway even if WS-10 and Al-31 had similar reliability, due to the fact that both Al-31 and WS-10 have similar performance and are underpowered relative to the aircraft, and both are thus very much interim engines.