What the Chinese think about Russian Su-35S

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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knowan

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Unread post11 Mar 2019, 18:00

fidgetspinner wrote:Now not to be a comedian


No need; posters here are well aware you are a joke, considering how many other accounts you've gone through on these forums.
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babybat{}.net

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Unread post11 Mar 2019, 18:53

milosh wrote:There is lot unknown about WS-15 for example you will see 180kN thurst which I don't see how they could pull from AL-31 size engine.

WS-15 based on R-79 Hot section from yak-141.
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sferrin

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Unread post11 Mar 2019, 19:14

babybat{}.net wrote:
milosh wrote:There is lot unknown about WS-15 for example you will see 180kN thurst which I don't see how they could pull from AL-31 size engine.

WS-15 based on R-79 Hot section from yak-141.


Show your supporting evidence.
"There I was. . ."
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tphuang

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Unread post11 Mar 2019, 21:04

weasel1962 wrote:Maybe people are reading too much into this. Last year I did a count and there are maybe 17 J-7 Air brigades (Scramble still shows 22) that could still be operation not including another 2-3 training units. All these need replacement.

The Su-35, being the most advanced fighter on sale from the Russians, could just be a gap filler whilst the PLAAF ramps up J-16 production. Looked how fast the PLAAF brought the Su-35 into service. Practically flying around Taiwan after delivery. Ease of induction suggests the Su-35 aren't too different from the other suks.

right on point here.

mixelflick wrote:So if it's outclassed by the J-10C and J-16, and its avionics and weapons are inferior to Chinese models. And the 117S will be obsolete soon... why did they buy it again?

I'm guessing range maybe?

Not sure if drop tanks were part of the package, but an SU-35 with tanks should be the longest ranged PLAAF fighter... perhaps even longer ranged than the J-20. I was just under the impression all along the engine was what they were acquiring it for. Either they did too (and found out otherwise), or they had some basic curiosity as to its "other" capabilities.

Sounds like after tearing it apart, they found most of it wanting?

I think they just needed replacement for a lot of frontline unit. Back when they started negotiation with Russians, it was not set in stone that J-16 would turn out successful. They have in the past made Russian purchases which seemed to make no sense later (like when they bought Sov destroyers). it was just a matter of having backup in case of domestic option gets delayed or has problems. When you are flushed with cash like PLA, buying 24 su-35 is not a big deal. There were stuff they definitely like about it, like the engine and Irbis radar.

mixelflick wrote:Tphuang, what do you mean when you say, "aerodynamically speaking the SU-35 is better than the other Flankers in Chinese service"?

I realize it's bigger, but the basic platform looks similar (if not identical) to earlier Flankers. Widely spaced engine nacelles, the "tunnel" providing space for lower drag weapons/lift/fuel. Blended wing/body, twin tails, etc.. The basic Flanker airframe looks draggy, and that seems to be true of the SU-35 as well.

Is there something special about that SU-35 that aerodynamically sets it apart? For some reason, I'm just not seeing it...

Aside from having a more powerful and less smoky engine, I've read from Chinese sources that su-35 does turn better at various speed vs su-27/30. We'd need someone more familiar with flankers to comment here. But one thing I remember reading several years ago was that su-30mkk fixed certain turn limitations that su-27 had at transonic speed. I don't know how accurate that is.

J-16 is based on su-30mkk, so it's heavier (being two seated) than su-35. Also, SAC, which designed/manufactures J-16 using locally available components, just doesn't have the same ability to make the changes to flanker platform as Sukhoi, since it doesn't have all the data that Sukhoi has from years of developing/testing flankers.
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milosh

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Unread post12 Mar 2019, 08:46

sferrin wrote:
babybat{}.net wrote:
milosh wrote:There is lot unknown about WS-15 for example you will see 180kN thurst which I don't see how they could pull from AL-31 size engine.

WS-15 based on R-79 Hot section from yak-141.


Show your supporting evidence.


Couple of texts on net mentioned they bought documentation and engine from Russians. And if engine is +180kN as you can find on Chinese net then it must be big engine (not AL-31 size class), if it is really AL-31 size engine then Chinese achieved breakthrough in engine tech.
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weasel1962

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Unread post12 Mar 2019, 08:54

Actually, that's what the Russians claimed (about Yak 141), not Chinese claims.
https://tiananmenstremendousachievement ... g/yak-141/

The reality is that china probably got its engine tech from a number of sources especially Ukrainian.
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milosh

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Unread post12 Mar 2019, 10:42

weasel1962 wrote:Actually, that's what the Russians claimed (about Yak 141), not Chinese claims.
https://tiananmenstremendousachievement ... g/yak-141/

The reality is that china probably got its engine tech from a number of sources especially Ukrainian.


We are talking about engine size, that is why we mentioned russian sources about R-79. WS15 is 180kN class engine:

https://web.archive.org/web/20131208202 ... Summit.pdf

So if WS15 can replace AL-31 which they use in J-10 and J-11/16 then it would mean its dimensions are almost same as AL-31, but engine thrust class is more of F135 which is noticeable bigger engine so Chinese are leap ahead even Americans in engine tech (very unlikely) or WS15 is BIG probable even bigger engine then F135 if it is 180kN class that is why sources about R-79 need to be consider relevant.

If WS15 isn't 180kN class engine then that we could talk about replacing AL-31 engine family with it.
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madrat

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Unread post12 Mar 2019, 13:15

So which Chinese engine has CFM6 core technology?
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knowan

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Unread post12 Mar 2019, 21:33

milosh wrote:
weasel1962 wrote:Actually, that's what the Russians claimed (about Yak 141), not Chinese claims.
https://tiananmenstremendousachievement ... g/yak-141/

The reality is that china probably got its engine tech from a number of sources especially Ukrainian.


We are talking about engine size, that is why we mentioned russian sources about R-79. WS15 is 180kN class engine:

https://web.archive.org/web/20131208202 ... Summit.pdf

So if WS15 can replace AL-31 which they use in J-10 and J-11/16 then it would mean its dimensions are almost same as AL-31, but engine thrust class is more of F135 which is noticeable bigger engine so Chinese are leap ahead even Americans in engine tech (very unlikely) or WS15 is BIG probable even bigger engine then F135 if it is 180kN class that is why sources about R-79 need to be consider relevant.

If WS15 isn't 180kN class engine then that we could talk about replacing AL-31 engine family with it.


The Chinese were claiming 9:1 T/W ratio with a 36,000 lbf thrust figure, so that's a 4000 lb dry-weight engine versus AL-41 in the 3,500 lb dry-weight class.

It certainly is a heavier engine, closer to the F135 in weight (which has been estimated anywhere from 3700 to 5000 lbs) than the AL-41, but the volume might still be close enough for it to replace the AL-41.

It is highly likely to require airframe changes though, so any J-11/15/16 with the WS-15 would require new airframes, it wouldn't be possible to retrofit existing planes with the engine.
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weasel1962

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Unread post13 Mar 2019, 06:37

Not sure where that WS-15 info is gotten from. AFAIK, the original published source of WS-15 thrust was a conference brochure back in 2013.

https://web.archive.org/web/20131208202 ... Summit.pdf
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inst

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Unread post31 Jan 2021, 06:11

Some things that weren't mentioned:

Su-35 had greater fuel capacity than the J-16. Since the Chinese aren't behind the Russians in composites, it implies the Russians were more canny with their composites use. The Su-35, notably, seems to have a fuel fraction nearly at the level of the F-35 without resorting to CFTs.

The most common theory about the Chinese Su-35 purchase is that the Su-35s were purchased for the engines, but I think, consider that the Chinese bought the CFM-56 and took more than 15 years to get it into a remilitarized operational state. Another emphasis is on the TVC; the Chinese operate no TVC engines to date, and the Su-35s gave them their first TVC-equipped fighter, earlier than the J-10B with a TVC nozzle.

What I think the theory misses, however, is the FCS integration with TVC. The Chinese had considerable levels of research into TVC engines, so the part they're more likely to be missing is the FCS integration, not the TVC itself. The Su-35 provides an example of a flight control system that incorporates TVC, a feature they missed when they purchased Su-30s the last time around. That would expediate their TVC fighter production.

As for the Chinese crapping on Russian missiles, the Su-35S purchase was roughly after the PL-XX (XLR missile) and PL-15 entered service. Estimates of the PL-15's range are in the 200-300 km range, so they'd obviously outmode Russian missiles of current or earlier generations. The K-77 for the Su-57, in comparison, is reputed to only have about 200 km of range. Likewise, the PL-XX seems to be a lighter missile than the R-37M the Russians use for interception. I wouldn't say it's so much that Russian missiles are terrible (except perhaps by US standards), but the Chinese bought last-generation missiles from the Russians while employing current generation missiles themselves.

===

As for the Su-35's PESA, well, it's a PESA. 2.5 dB signal losses from the radar architecture, or rather AESA saves 2.5 dB compared to PESA. You'd expect about 44% of the input energy to be lost while going through the architecture, resulting in a 13.5% loss in range. The Chinese went earlier on AESA than the Russians, with J-16s purportedly having an L-Band AESA, and the Type 055 destroyer supposedly running a Gallium Nitride AESA of some sort. So obviously the Chinese wouldn't be too impressed with the Su-35 running a PESA radar when they've got AESAs out the wazoo (J-10Cs run AESA, J-16s run AESA, J-20s run AESA, the possibly cancelled upgrade of the J-11 was supposed to run AESA).
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