-Original WS-10 had spool up time issues that we knew existed at 2002, possibly until 2006-2007
I don't think so. If i am correct, the original ws10 ceased with development around the end of 1990s, beginning of 2000s. WS10A must've began development earlier than 2000 because as early as 2002 it was flying on an j11 testbed. as per those links i've given.
-WS-10A, revised from WS-10, experienced a few production problems but fully went into production by 2009, equipping over a hundred J-11Bs since then
true. After it has been in development for some ten years. That's really the main point of my story. No, i can't really prove it, of course, but there are sources mentioning ws10A as early as 2002. There are sources saying chinese contracted Saylut with j10 engine back in 1992! (again, i provided a link) Meaning even back then, in the same year original ws10 first time came online, it was evident that variant wasn't going to cut it. Hence, i theoretize about early efforts (possibly through salyut) on ws10a, earlier than most people think.
-Spool up time problem has not been solved because:
A: WS-10A is not equipping J-10s (it is a one engined plane as opposed to J-11B, meaning it is safer?)
Usually i am not of opinion that twin engined planes are SO much safer because of their extra engine that they have an edge over single engined ones. but IF its true that spool up time is 50-100% longer, as per that pilot interview, that could be enough of a reason to wait a bit until new ws10 variant.
B: WS-10A is not equipping J-15s (it is a carrier based aircraft where spool time is more important as opposed to J-11B?)
Yes, when j15 is landing on the carrier.
C: spool up time issues are simply difficult to be solved without long arduous redesign
Yes, because spool up time, as far as i've managed to gather, mostly depends on mass of the system. the bigger the mass, the harder it is to move it and longer it takes to spool up. So having more elements in the turbine makes it heavier and harder to spool up. pretty much most engines now, al31 included, have two single stage turbines. (there is one exception, the f135, going back to three part turbine, but being as advanced as it is, perhaps that was a planned tradeoff that such a cutting edge engine can afford) ws10, as well as f100 and other US engines from 1970s have three turbine stages. also, there's the matter of weight of each of those subsystems. there were indications ws10a had issues with compressor being overweight in 2005. all that can add up and make the engine parts heavier and harder to turn.
D: we have not heard of the problem being solved
true, i havent read anywhere the issue is truly solved. but, if i do see a ws10 variant on j15 or j10 in service, i will consider it mostly solved. perhaps not by redesigning the turbine layout but by making parts lighter.
I have a problem mostly with assumptions underlying point A. Even if we do believe WS-10A has a spool time issue, the fact that it is equipping J-11Bs means it should be able to equip J-10s as well, seeing as both are land based fighters and have no need for J-15's sudden acceleration during landings. If we believe WS-10A isn't on J-10s because of a reliability/confidence issue, then that is the reason WS-10A isn't on J-10, and spool up time has nothing to do with it.
Again, why then the pilot interview who explicity said spool up was reason why j10 didnt get the engine yet.? j10 may still need sudden acceleration after restarting a problematic engine, since its the only engine it has. j11 may restart one engine while enjoying the full, uninterrupted thrust of the other engine. that's why it might be regarded as safer.
Ultimately the reason I am not drawn to this spool up problem can be summed in two routes:
1: We should still be hearing about it if it were an issue
2: I think we are using the engine's presence or therelack of, upon various aircraft, and making various guesses about said aircraft's demands for performance, to "reverse engineer" a very specific explanation (in this case, spool time being a problem for J-15 but not J-11B), which may be explained by a variety of other, equally likely explanations -- that is to say, I think the assumptions A and B are dubious at best. Basically I think too many circumstantial assumptions are being made on top of each other while we ourselves hold very little solid evidence and knowledge (in my case, knowledge about developing and re developing turbofans), to hypothesize a highly complex conclusion.
one never knows with chinese. some stuff is reported, some isn't. chinese programmes are bound to be beset with issues, just like any other development programmes in the world. but the media system reporting them just doesnt exist in china in the same manner as it does in US, where we hear about every little screwup on LCS, JSF, etc etc. It doesn't mean one is superior over the other. one just gets reported way, way more.
Also, good news tends to be reported more by closed media like chinese. But so far we have not heard anything about spool up issue after it was still present in 2007. what is more likely - that the problem was rectified but not reported on? or that there wont be a report until there's something good to report on? i'd go with the latter.
There is little solid evidence, that's true. But what tiny bit of circumstantial evidence there is points against spool up qualities, while there's zero mention of that being solved so far.
i really hope all this will be behind us with some new variant. perhaps as early as this year. whatever may or mayve not happened before won't matter then anymore.
But it's always interesting to read different views on a topic. I really hope we'll get more bits of info soon. That longer nozzled ws10 engine on j11 is a really curious beast. While it could be just a small modification of the nozzle itself, it could also be a sign of comprehensive set of changes, perhaps pointing out to a whole new variant. J10 variant, with different gearbox, could then follow suit fairly shortly.
