Chinese Engine Development

kentchang said:

This only means the engine specs haven't changed. The below link is from 2017. It is entirely possible the recent quote is based on the same but old sources. I also remembering an Aviation Week article comparing the number of engineers working for COMAC vs the established Western engine makers at that time. I think COMAC number was only 1/10 and the article rightful questioned how COMAC expects to catch up without much bigger investments in talents and money. I wonder what is the AECC corporate size growth is between 2015 and 2025.

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SHANGHAI—Aero Engine Co. of China (AECC), developing the CJ-1000 turbofan for the Comac C919 airliner, is aiming at what it believes is a specification only slightly inferior to those of rival engines. Thrust-specific fuel consumption in cruise for the initial version of the engine, the CJ-1000A...

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its like day and night difference if we compare 2017 vs 2024..

AECC Shanghai raised 5.9 Billion RMB investment alone in 2023 year.. The current overall valuation exceed 30 Billion Yuan.. total assets were at 12.5 Billion RMB.

2024 investment will be 10+ Billion RMB..

AECC Shanghai Branch total employees are now in Thousands.. in R&D team mostly are PHD holders in respective departments. 50% Employees are gold medalist in R&D team. it is known that, Shanghai AECC team is the most technical and capable Engine team in whole of China. all are top minds.
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if we combine all subsidies of AECC. like Shenyang , Xian , Guizhou , Shanghai , Beijing. then total number of Employees cross 150,000 mark.

Just got this 察话会au podcast hosted by Yankee & Co. two days ago, which generally discussed about domestic aircraft engine development progress for the C919 and C929, and the looking forward to the future development of large aircraft.


Key points summed up from the podcast, listed by a comment:

1. AX比A大，AX是练手项目（14t推力）
2. 有国外部件和大量厂所院所产品
3. 上Y-20试飞台的是CJ-1000
4. 短舱计划商发自己做
5. 取证时间预计2030
6. CJ-2000进度相对CJ-1000要快
7. 1000、2000大量使用复材，包括不限于进气道/叶片
8. 复材叶片树脂整体浸润压制，类似蜜蜡的外观质感，叶片前缘使用金属包边（可能是钛合金），第一代是钛合金全金属中空叶片，只比复材版本略重
9. CJ-2000是验证机状态，已经进行推力实验，今年年底见原型机
10. 俄发PD-35进度和CJ-2000相比较为完蛋
11. 商发目前体感是超大号博士生站，摸索中全面正向研究。正在大力建设，重视实验室建设，有14mx14m巨大试车间
12. 商发实验条件有后发优势，甚至可以去帮助中行的任务实验
13. CJ-1000A和Leap-1C油耗略高，噪音略低（展板对比）
14. 27-28预计开始CJ-1000版C919的试飞工作
15. C919有一般CXF版的全国产版本设计（可实现节点碰巧对齐了2027年时间节点，某种政治反掐脖子威慑）
16. C929国外动力还未公布，CJ-2000（33吨）展板对比的是GEnx（34吨，787动力）
17. 师座下判断29年C929首架下线
18. 师座下判断CJ-2000进度是CJ-1000进度＋3-4年，差不多C929在取证末期时CJ-2000可用可以开始上C929取证

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Roughly translated:

1. (CJ-1000)AX is larger than (CJ-1000)A, and (CJ-1000)AX can be said as a practice project (14 tons of thrust);
2. It (CJ-1000/A) includes foreign components and a large number of products from domestic factories and institutes;
3. The engine being tested on the Y-20 flight test platform is the CJ-1000;
4. ACAE plans to develop the nacelle (for the CJ-1000/A) on its own;
5. Certification (of the CJ-1000) is expected in 2030;
6. The progress of CJ-2000 is relatively faster compared to CJ-1000;
7. Both CJ-1000 and CJ-2000 extensively use composite materials, including but not limited to the intake and blades;
8. The composite material blades are fully impregnated and pressed with resin, resembling a bee-waxy texture in appearance, with metal edges (possibly titanium alloy) on the leading edge of the blades. The first generation features hollow all-metal titanium alloy blades, and is only slightly heavier than the composite version;
9. CJ-2000 is in the demonstrator stage and has already undergone thrust testing. The prototype will be seen by the end of this year;
10. The progress of the Russian PD-35 engine is relatively (in not considerably) behind that of the CJ-2000;
11. The current perception of ACAE is that it operates like a large-scale Ph.D. station, engaging in comprehensive forward-looking research through exploration. It is actively expanding and placing a strong emphasis on laboratory construction, with a huge test workshop measuring 14 meters by 14 meters;
12. ACAE's experimental conditions have the latecomer advantages, and it can even assist with the tasks of the AECC;
13. The fuel consumption of the CJ-1000A is slightly higher than the Leap-1C, while the noise level is slightly lower (according to the display board comparison);
14. Test flights of the CJ-1000 version of the C919 are expected to begin around 2027-2028;
15. The C919 has a design for a fully domestically-produced version (potentially aligning with the 2027 timeline, which serves as a political deterrent against potential sanctions);
16. The foreign engine for the C929 has not yet been announced. The CJ-2000 (with a thrust of 33 tons) is compared with the GEnx (34 tons of thrust, the engine for the Boeing 787) on the display board;
17. It is estimated that the first C929 will be rolled out in 2029; and
18. It is estimated that the progress of CJ-2000 is faster than that of the CJ-1000 by 3-4 years. By the end of the C929 certification, the CJ-2000 will be ready and can begin the certification process on the C929.

an even higher fuel consumption rate than the 1-C? that's not good.....

ACuriousPLAFan said:

Just got this 察话会au podcast hosted by Yankee & Co. two days ago, which generally discussed about domestic aircraft engine development progress for the C919 and C929, and the looking forward to the future development of large aircraft.

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Key points summed up from the podcast, listed by a comment:


Roughly translated:

1. (CJ-1000)AX is larger than (CJ-1000)A, and (CJ-1000)AX can be said as a practice project (14 tons of thrust);
2. It (CJ-1000/A) includes foreign components and a large number of products from domestic factories and institutes;
3. The engine being tested on the Y-20 flight test platform is the CJ-1000;
4. ACAE plans to develop the nacelle (for the CJ-1000/A) on its own;
5. Certification (of the CJ-1000) is expected in 2030;
6. The progress of CJ-2000 is relatively faster compared to CJ-1000;
7. Both CJ-1000 and CJ-2000 extensively use composite materials, including but not limited to the intake and blades;
8. The composite material blades are fully impregnated and pressed with resin, resembling a bee-waxy texture in appearance, with metal edges (possibly titanium alloy) on the leading edge of the blades. The first generation features hollow all-metal titanium alloy blades, and is only slightly heavier than the composite version;
9. CJ-2000 is in the demonstrator stage and has already undergone thrust testing. The prototype will be seen by the end of this year;
10. The progress of the Russian PD-35 engine is relatively (in not considerably) behind that of the CJ-2000;
11. The current perception of ACAE is that it operates like a large-scale Ph.D. station, engaging in comprehensive forward-looking research through exploration. It is actively expanding and placing a strong emphasis on laboratory construction, with a huge test workshop measuring 14 meters by 14 meters;
12. ACAE's experimental conditions have the latecomer advantages, and it can even assist with the tasks of the AECC;
13. The fuel consumption of the CJ-1000A is slightly higher than the Leap-1C, while the noise level is slightly lower (according to the display board comparison);
14. Test flights of the CJ-1000 version of the C919 are expected to begin around 2027-2028;
15. The C919 has a design for a fully domestically-produced version (potentially aligning with the 2027 timeline, which serves as a political deterrent against potential sanctions);
16. The foreign engine for the C929 has not yet been announced. The CJ-2000 (with a thrust of 33 tons) is compared with the GEnx (34 tons of thrust, the engine for the Boeing 787) on the display board;
17. It is estimated that the first C929 will be rolled out in 2029; and
18. It is estimated that the progress of CJ-2000 is faster than that of the CJ-1000 by 3-4 years. By the end of the C929 certification, the CJ-2000 will be ready and can begin the certification process on the C929.

Click to expand...

with due respect to Yankee & Co.. there are many outdated and wrong information in this discussion. let me clear one by one.

ACuriousPLAFan said:

It (CJ-1000/A) includes foreign components and a large number of products from domestic factories and institutes

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this is the topic we have discuss before many times..

CJ-1000 engine high end nut , bolt , and especially Bearings have been imported from a Scandinavian country.. this was during 2021. i have had long discussion with my source on this..
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Beijing Institute of Aeronautical Materials exceeded 50,000 hours, marking a new breakthrough in my country's high-end equipment manufacturing technology.

The key component of the fatigue test was the main bearing of an aero-engine independently developed by my country. It did not fail in the equivalent accelerated fatigue life of 50,000 hours on the tester, setting a new record in my country.

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so there is high possibility that those imported Bearings have replaced with domestic one already.

i m repeating again, all core components of CJ-1000 ENGINE are domestically produced.

high pressure compressor
Combustion chamber (it is 3D printed design)
High pressure turbine/blades/disk

Wuxi city has many core suppliers in CJ-1000A engine. blades/turbine disk/rotor bearings/FADEC are produced in this city.

ACuriousPLAFan said:

ACAE plans to develop the nacelle (for the CJ-1000/A) on its own;

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AECC Shangfa successfully developed CJ-1000A nacelle already.. back in 2022. i m posting the link as well


so this is completely wrong that, they are planning to develop.. its already developed and manufactured.
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Nacelle reverse thruster also successfully developed by AECC Chengdu




Nacelle+reverse thruster complete set have successfully developed.

ACuriousPLAFan said:

Certification (of the CJ-1000) is expected in 2030

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Certification will be completed before 2030..

ACuriousPLAFan said:

The foreign engine for the C929 has not yet been announced. The CJ-2000 (with a thrust of 33 tons) is compared with the GEnx (34 tons of thrust, the engine for the Boeing 787) on the display board;

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Zhuhai air show 2022, COMAC display Trent700 ENGINE alongside C929..



not saying, this is 100 percent confirmed but COMAC intent to use Trent700 in first C929 flight.. though there is a strong chance that, CJ-2000 will catch up C929 development..

CJ-2000 total thrust will be 78,000+ lbf.. exceed 35 tons. officially confirmed by AECC..

G'day. I came across someone (I unfortunately forgot where but I remember the details) who said they read a Chinese research paper in 2018/19, and I've been trying to find it.


He said the paper was about a variable cycle engine. This variable cycle engine was apparently based on an existing conventional turbofan design, and VCE components had been added to it as a validation platform. It wasn't relatively fancy like the XA100 with a three-stream design, but rather closer to the YF120, using a CDFS (Core Driven Fan Stage) and employing a two-stream variable cycle design.

He claimed that the study paper said the CDFS' was design was based on/modified from another existing engine's 1st high-pressure compressor stage. And the compressor system consisted of one stage CDFS, consisted of 3 rows of blades (which were the variable inlet guide vanes, rotor, and stator), 8-stage HP compressor and no inlet guide vanes.

He also said the engine's CDFS didn't employ a open-close system to change the bypass ratio like the YF120, but rather by changing the VIGV's angle of attack (apparently from 20°~30°) and variable stators to achieve the two-stream VCE design.

The engine was also said to have no inlet guide vanes for the HP compressor section (like the YF120). Instead, the CDFS inlet guide vanes, CDFS stators, the stators 2 stages in front of the HP compressor, and FVABI are all adjustable. The CDFS, FVABI, and HP compressor are a 'pneumatic integrated design'.

The paper said the engine performed well during tests, and the CDFS was well coupled with the HP compressor, satisfying the design objectives.


Now, onto my actual question. I looked up the buzz words of said paper, like CDFS (核心机驱动风扇), VIGV (进口可调导叶), etc. but I couldn't seem to find the paper. Does this paper actually exist?

Alfa_Particle said:

G'day. I came across someone (I unfortunately forgot where but I remember the details) who said they read a Chinese research paper in 2018/19, and I've been trying to find it.


He said the paper was about a variable cycle engine. This variable cycle engine was apparently based on an existing conventional turbofan design, and VCE components had been added to it as a validation platform. It wasn't relatively fancy like the XA100 with a three-stream design, but rather closer to the YF120, using a CDFS (Core Driven Fan Stage) and employing a two-stream variable cycle design.

He claimed that the study paper said the CDFS' was design was based on/modified from another existing engine's 1st high-pressure compressor stage. And the compressor system consisted of one stage CDFS, consisted of 3 rows of blades (which were the variable inlet guide vanes, rotor, and stator), 8-stage HP compressor and no inlet guide vanes.

He also said the engine's CDFS didn't employ a open-close system to change the bypass ratio like the YF120, but rather by changing the VIGV's angle of attack (apparently from 20°~30°) and variable stators to achieve the two-stream VCE design.

The engine was also said to have no inlet guide vanes for the HP compressor section (like the YF120). Instead, the CDFS inlet guide vanes, CDFS stators, the stators 2 stages in front of the HP compressor, and FVABI are all adjustable. The CDFS, FVABI, and HP compressor are a 'pneumatic integrated design'.

The paper said the engine performed well during tests, and the CDFS was well coupled with the HP compressor, satisfying the design objectives.


Now, onto my actual question. I looked up the buzz words of said paper, like CDFS (核心机驱动风扇), VIGV (进口可调导叶), etc. but I couldn't seem to find the paper. Does this paper actually exist?

Click to expand...

This one?

兼顾两种模式核心机驱动风扇级气动优化设计​

vincent said:

This one?

兼顾两种模式核心机驱动风扇级气动优化设计​

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Does seems like it. However, it doesn't mention the 'based on an existing domestic turbofan' and actual trial results that I'm interested about.

Cause although I probably am indeed talking out of my hat here, I have a small crackpot theory.

The person who told me about this research paper seemed to think that the 'existing domestic turbofan' that the paper's engine was on about is a version of the WS-10, since the paper apparently mentioned a 8 stage HP compressor.

However, the research paper (and this one) he talked about was published in 2018, the same year that WS-15 was rumored to have a project revamp.

What if it's not the WS-10? What if the 'existing engine' that the engine in the paper was based on was the old, pre-2018 WS-15, and the engine in the paper was a actually concept/validation of the new WS-15?

In my head, this makes sense. It might explain how the new WS-15 have a quite staggering thrust of 181 kN, while still being able to have supercruising as a main design focus (since, to my understanding, they're conflicting interests).

So if this paper is real, could the WS-15 be a two-stream VCE like what the YF120 was supposed to be?

Again, this is just a crackpot theory, based on just research papers and some whacky correlation and nothing else, really. I'm just putting forth a what-if here. (shrug)

Alfa_Particle said:

Does seems like it. However, it doesn't mention the 'based on an existing domestic turbofan' and actual trial results that I'm interested about.

Cause although I probably am indeed talking out of my hat here, I have a small crackpot theory.

The person who told me about this research paper seemed to think that the 'existing domestic turbofan' that the paper's engine was on about is a version of the WS-10, since the paper apparently mentioned a 8 stage HP compressor.

However, the research paper (and this one) he talked about was published in 2018, the same year that WS-15 was rumored to have a project revamp.

What if it's not the WS-10? What if the 'existing engine' that the engine in the paper was based on was the old, pre-2018 WS-15, and the engine in the paper was a actually concept/validation of the new WS-15?

In my head, this makes sense. It might explain how the new WS-15 have a quite staggering thrust of 181 kN, while still being able to have supercruising as a main design focus (since, to my understanding, they're conflicting interests).

So if this paper is real, could the WS-15 be a two-stream VCE like what the YF120 was supposed to be?

Again, this is just a crackpot theory, based on just research papers and some whacky correlation and nothing else, really. I'm just putting forth a what-if here. (shrug)

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I wouldn't go that far. If the actual WS-15 being developed was a VCE, I think we would know about it. And also, it is very unlikely that such a major variant of WS-15 would be allowed to be pursued as intended for fit onto J-20A in an acceptable timeline.

We know they are working on VCEs however, and they probably have multiple paths for it and I wouldn't be surprised if one of the steps was adapting an existing engine as a VCE for testing purposes. It is very within reason that a WS-15 or a WS-10 could have been developed as a test VCE. However it's unlikely it would be developed intended for production at this stage. For J-20A? Forget it imo

Blitzo said:

I wouldn't go that far. If the actual WS-15 being developed was a VCE, I think we would know about it. And also, it is very unlikely that such a major variant of WS-15 would be allowed to be pursued as intended for fit onto J-20A in an acceptable timeline.

We know they are working on VCEs however, and they probably have multiple paths for it and I wouldn't be surprised if one of the steps was adapting an existing engine as a VCE for testing purposes. It is very within reason that a WS-15 or a WS-10 could have been developed as a test VCE. However it's unlikely it would be developed intended for production at this stage. For J-20A? Forget it imo

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A two-stream VCE is technically 80s technology, and relatively easier to achieve than three-stream ACEs like the XA100. It's arguably not too groundbreaking since according to the research paper, all they're doing to achieve BPR variations are by changing VIGV AoA and incorporating a CDFS. Really, in principle, all you're doing is using VIGV/stators to block the core bypass channel and directing the airflow back to the core.

It took roughly 5 years for WS-15 to go from project revamp to LRIP, and GE also took even less (IIRC) for the YF120 to reach dem/val. Considering they can apply what they learned from the WS-10 series, their material breakthroughs, and the fact that they aren't exactly making a two-stream VCE from scratch (since according to the paper it's somewhat based on an existing design), I would say it's not exactly unreasonable.

As for the we would know about it part... Really? WS-15's specs are really under wraps. We don't even know how many stages the LP/HP compressor/turbine have.

We know they're working on ACE projects from academic journals too, similar kind of situation as this particular two-stream VCE. I don't recall it was leaked by insiders first (could be just my memory).

But it's just a crackpot theory on my part anyways, based on lots of extrapolation. I wouldn't completely dismiss it though. It's not highly unlikely, just 'maybe'.

Alfa_Particle said:

A two-stream VCE is technically 80s technology, and relatively easier to achieve than three-stream ACEs like the XA100. It's arguably not too groundbreaking since according to the research paper, all they're doing to achieve BPR variations are by changing VIGV AoA and incorporating a CDFS. Really, in principle, all you're doing is using VIGV/stators to block the core bypass channel and directing the airflow back to the core.

It took roughly 5 years for WS-15 to go from project revamp to LRIP, and GE also took even less (IIRC) for the YF120 to reach dem/val. Considering they can apply what they learned from the WS-10 series, their material breakthroughs, and the fact that they aren't exactly making a two-stream VCE from scratch (since according to the paper it's somewhat based on an existing design), I would say it's not exactly unreasonable.

As for the we would know about it part... Really? WS-15's specs are really under wraps. We don't even know how many stages the LP/HP compressor/turbine have.

We know they're working on ACE projects from academic journals too, similar kind of situation as this particular two-stream VCE. I don't recall it was leaked by insiders first (could be just my memory).

But it's just a crackpot theory on my part anyways, based on lots of extrapolation. I wouldn't completely dismiss it though. It's not highly unlikely, just 'maybe'.

Click to expand...

I consider it very reasonable that we do not know WS-15's specs or how many stages it has etc.
However if WS-15 had been redeveloped to a VCE during this period then I am certain we would have heard a hint of it.

That's not a level of redesign that can just go without a rumour leaking out of it.



Let's put it this way -- the idea of a VCE variant of WS-15 (or WS-10) being developed for testing as part of overall VCE efforts, makes sense.
However I see no reason to entertain the idea that the WS-15 intended for production on use for J-20A, is redesigned/revamped as a VCE. The threshold for us to even have the right to consider that as an idea, is something which hasn't been reached yet, I believe.