Chinese Engine Development

minusone said:

So you cite lack of new information as reason to uphold your claim, and then you proceed to cite random forum posters' claims about ws-10c running harder in the expense of MTBO which was not official.

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You need to re-read my post. I took onboard the new info regarding maximum thrust but (correct me if I'm wrong...) no new data points regarding life/TBO came to light in this release. So my earlier rationale on this specific topic, as stated, remains unaffected because I don't see any additional evidence that tphuang's assertion quoted in the screenshot might be founded on. Or do you for once have something substantive to support it?

minusone said:

This whole things about ws-10c compromised badly on MTBO for increased thrust seems to be a product of confirmation bias than anything else.

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Stating the WS-10C is "badly" compromised on MTBO is your words not mine.

All I did is to adopt for argument's sake the statements that it has a) a static thrust increase to 15tf and b) reduced BPR . To achieve both at the same time requires the WS-10C to be run even hotter compared to the -B than the difference between the 117/117S. I don't know whether either claim is true (though 15tf seems completely plausible, if the WS-10B is >14tf), but IF they are, that is just how the cookie crumbles. Unless the WS-10C is in fact a significantly different engine to the -B in terms of materials & cooling, this in turn means TBO will suffer a penalty.

Could the WS-10 in fact be a completely different engine? The possibility can't be entirely excluded I suppose, but to bring the WS-10B to >14tf without ruining TBO/life probably requires all the 5th gen tech insertions it can get already. As is the case in the very similar 117/117S or GE F110-GE-129/-132, the base engine is likely to be mostly the same, with the higher-thrust variant accepting somewhat lower durability. With WS-10 production having ramped up so dramatically to now equip the entire PLAAF fighter procurement volume, chances are very good that it follows the same template for economies of scale, if nothing else.

And again, whether that makes the WS-10C a "bad" compromise is not something I opined on at all. I was just making a comparison.

minusone said:

Also the WS-10c serrated nozzle with cooling vents indicated the design was meant to be VLO.

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Err... yes? What makes you think anybody was doubting this? You can add the composite material used for the outer nozzle petals, BTW (likely reduces IR emissions).

I'm merely surprised it didn't adopt the con/di principle from the J-16 WS-10B, as the other changes (thrust hike, possibly reduced BPR) indicate supersonic dry thrust was a major goal, and a con/di nozzle would help this too. My hunch, as stated, is that LO requirements are precisely what may have prevented that, though likely IR rather than RCS, given that an ejector nozzle as used on the J-10 and J-20 has advantages in this respect..

Please read before ranting!

The thrust figures for WS-10A/B/C are from Deino, although again this is static thrust and doesn’t tell the whole story.

There is some numbers from Pakistani brochure that seem to agree with these numbers but then again PAF brochures aren’t necessarily the most reliable. With statements on how AL-31FM2 and WS-10C affects performance on J-20 (the closest we have to apples to apples comparison), I think we can say that WS-10B/C is roughly in line with AL-41F1/F1S in static thrust.

What’s interesting is in the early 2010s, there was lot of overly optimistic information about AL-41F1, like how it’s a 15 metric ton thrust engine (which is only the emergency power, normal max thrust is 14.5 tons), how it’s 150 kg lighter than AL-31F (now it’s considered to be about 1,600 kg, about the same as AL-41F1S), and how it’s fundamentally different from even the AL-41F1S (now it’s reported the main difference is the engine control system).

About WS-10A/B/C, I thought that WS-10A is for J-11 and WS-10B is for J-10? But now some are saying WS-10B powers both J-11/16 and J-10? I know early WS-10 and WS-10A had quality and lifespan issues, but the engines that fixed these and are on J-11 is still called WS-10A?

RadDisconnect said:

What’s interesting is in the early 2010s, there was lot of overly optimistic information about AL-41F1, like how it’s a 15 metric ton thrust engine (which is only the emergency power, normal max thrust is 14.5 tons), how it’s 150 kg lighter than AL-31F (now it’s considered to be about 1,600 kg, about the same as AL-41F1S), and how it’s fundamentally different from even the AL-41F1S (now it’s reported the main difference is the engine control system).

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I think those were mostly speculative guesses based on rumours (no idea where they originated) that it was going to get a new, 7-stage HPC & 3-stage LPC - I wouldn't dignify that with the term "information" Had those changes come to pass, this kind of improvement in T/W ratio would not have been totally unreasonable to expect, but I was always skeptical that it was going to differ so drastically. For much the same reasons as outlined above, incidentally.

Tirdent said:

I think those were mostly speculative guesses based on rumours (no idea where they originated) that it was going to get a new, 7-stage HPC & 3-stage LPC - I wouldn't dignify that with the term "information" Had those changes come to pass, this kind of improvement in T/W ratio would not have been totally unreasonable to expect, but I was always skeptical that it was going to differ so drastically. For much the same reasons as outlined above, incidentally.

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Actually some of this info came from Mikhail Pogosyan.


That said the AL-41F1 was always meant to be an operational engine for production Su-57s and sources say that Sukhoi T-50 submission for PAK-FA always had AL-41F1 or izd.117 and was meant to be in production aircraft, while a new engine was envisioned for future upgraded variants. So I wonder if Pogosyan was making statements about both AL-41F1 and izd.30 and the journalist accidentally conflated them. Otherwise there is such a vast difference from what is reported here and what we know now that it doesn't make sense.

Now, about the WS-10C, was it ever planned for J-20 to mount this engine, or was this decision made later so that the J-20 can be fully indigenous without needing to rely on Russian engines while the WS-15 isn't ready yet? Also the fact that J-20 uses ejector nozzle instead of a con-di nozzle even though it's used on J-11/16, might point to IR signature reduction as a reason and worth the performance penalty.

RadDisconnect said:

Now, about the WS-10C, was it ever planned for J-20 to mount this engine, or was this decision made later so that the J-20 can be fully indigenous without needing to rely on Russian engines while the WS-15 isn't ready yet? Also the fact that J-20 uses ejector nozzle instead of a con-di nozzle even though it's used on J-11/16, might point to IR signature reduction as a reason and worth the performance penalty.

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Original plan was always to fly the J-20 with WS-10s as the interim solution for the WS-15s. It was the Russian engines that had to be adopted as an interim solution because the WS-10 encountered various development problems early on. China clearly had no issues with relying on Russian engines before, so insofar as we’re trying to read something with the switch to domestic engines, it’s more likely the case that the switch was done because its performance was either comparable or an improvement, and not simply because of some urgency with the need for self sufficiency. They clearly took their time with the WS-10 adoption since the WS-10 itself was in mass production for a few years before the switch was initiated.

Initial versions of the WS-10 lacked thrust to be used on the J-20. They were fine for the Flankers. Both aircraft have roughly the same weight of the airframe but for whatever reason China wanted more engine performance. From comments made by the Russians I think China wanted import the Al-41F1 for J-20 but the Russians denied it. The engine the Russians provided has similar thrust levels anyway. But it uses older technology.

I think the Russians want to keep the latest generation to themselves so they have something to export. i.e. they will sell whole systems with latest generation hardware but not isolated components.

Looking at Deino's tweet regarding the WS-10 with the military thrusts for the later WS-10 variants remaining unknown, it got me curious whether military thrust tends to scale linearly with afterburner thrust, or will afterburners provide diminishing returns as military thrusts goes higher?

Another name for the afterburner is reheat. You basically dump fuel on the unburned exhaust and get extra thrust that way. The performance of the afterburner varies according to the afterburner design. But is some percentage of the military thrust.

The this is a hydrogen turbine core being tested by the 3rd institute of CASIC. I couldn't find a single corroborating source. Does anyone know more about this? Is there a press release somewhere?

Oxyhydrogen Continuous Detonation Rocket Engine (OHCDRE) developed by Beijing Aerospace Propulsion Institute has passed the first "hot test verification (热试验考核)". Stable, self-sustained dentonation wave (稳定自持的单波爆轰波) was created and the wave speed reached 2200m/s in the test.

In the next steps, the team will study different design combinations of fuel injection and combustion chamber to push the potentials of OHCDRE.

据微信公众号“北京航天动力研究所”1月6日消息，该所研制的氢氧连续爆轰火箭式发动机完成首次热试验考核。

近日，我所低温液体推进技术实验室新型动力研究团队在一〇一所北京云岗试验区完成了氢氧连续爆轰火箭式发动机（OHCDRE）首次试验，试验形成稳定自持的单波爆轰波，爆轰波传播速度达2200m/s，燃烧效率相对传统爆燃燃烧大幅提升，试验达到预期目标。本次试验为研究团队在新型低温液体动力领域的进一步探索与尝试，并初步摸索了氢氧爆轰波的自持工作边界和高室压条件下氢氧爆轰可行性，为后续工程化应用奠定了基础。

研究团队与清华大学、北京大学、南京理工大学等多所高校团队紧密结合，对掺混结构、喷管型面、点火时序等开展了大量仿真研究，先后解决了设计、工艺、试验等关键技术，本次试验成功标志着氢氧连续爆轰火箭式发动机取得了重要进展。

后续，研究团队将进一步开展多种喷注方案和多种燃烧室方案组合下的连续爆轰研究，继续探索氢氧连续爆轰发动机的潜力，推动连续爆轰发动机的工程化应用。

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