XF9 is intended to be a concept verification prototype for the F-3.
Chinese Engine Development
- Thread starter jackbh
- Start date
No you missed an important caveat I mentioned that explains why Japan's XF9 doesn't count ... just like China's WS-15 (far superior to XF9 given what we know and far closer to service). I also didn't count Russia's Project 30 engine.
Screenshot for your reference.
Anyway... Japan has superior materials for now. I recall some member posting information on a Chinese engine conference explaining that the Japanese have broken through to the lead in materials with 5th gen or 6th gen materials which no one else is currently at. This doesn't necessarily mean they're ahead in engine making. It is but one aspect (albeit important) in thousands when it comes to making turbofans. Japan till date has not put into service a single high thrust low bypass turbofan. China has used their own for over 10 years now and iterated so many times, it's hard for us to even keep track and we simplify the family into WS-10A, WS-10B, WS-10 TVC, and WS-10C but there are countless iterations in between, tested, evaluated, for improvement etc.
Japan these days when it comes to certain niche tech fields they are not that experienced or involved in are really a bunch of second rate geniuses working with first rate institutions and tools (a simplistic way to describe the entire ecosystem of resources they have at their disposal). China have world leading first rate geniuses working with third to second rate institutions and tools but in strategically important fields such as military technologies the Chinese have second to none funding levels (equivalent to US blank cheque style find me your 20 best engineers, organise, and get this done by xyz).
Japan spreads its talent and tools a little more focused. China is trying to catch up and lead in literally every single tech field. In many it's far behind and much more work required but find me a single exascale Japanese supercomputer... China has had two for over a year. China has generations and armies of first rate geniuses picked up to work in every tech field from aviation to software. China just spreads them far and thin. Japan as impressive as they are in space technology, simply cannot compare with China's. There are lots more effort put there. Where are the Japanese BYDs and CATLs in battery technology?
The point is China has a lot of talent and well organised but all the resources and people are spread far and thin. Despite this, China isn't far behind even in its weakest tech fields - turbofan engines.
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Guys, I am always confused with bypass ratio.
(1) What count as low bypass ratio? I searched that WS-10 has a bypass ratio of 0.89, this seems pretty high compared to the 0.56 of AL-31, 0.3 of F-119, 0.57 of F-135, and 0.382 of WS-15.
(2) WS-10 has significantly higher bypass ratio than AL-31, does that mean there is the possibility that the new J-20 with WS-10 might have worse high speed performance than J-20 with AL-31?
(3) I know that J-20 is optimized, aerodynamically, for supersonic maneuvers. However, WS-10 has way higher bypass ratio than the F-135 engine used by F-35 that is often ridiculed for having too high a bypass ratio for supersonic maneuvers. I know that F-35's inability to go supersonic is more due to its aerodynamic features rather than its engine. But looking at the bypass ratio of WS-10, I feel like J-20's supersonic performance, which it prides itself in, might be tooooooo boggled down by its current engine. Is this true or might there be other way of looking at it?
(1) What count as low bypass ratio? I searched that WS-10 has a bypass ratio of 0.89, this seems pretty high compared to the 0.56 of AL-31, 0.3 of F-119, 0.57 of F-135, and 0.382 of WS-15.
(2) WS-10 has significantly higher bypass ratio than AL-31, does that mean there is the possibility that the new J-20 with WS-10 might have worse high speed performance than J-20 with AL-31?
(3) I know that J-20 is optimized, aerodynamically, for supersonic maneuvers. However, WS-10 has way higher bypass ratio than the F-135 engine used by F-35 that is often ridiculed for having too high a bypass ratio for supersonic maneuvers. I know that F-35's inability to go supersonic is more due to its aerodynamic features rather than its engine. But looking at the bypass ratio of WS-10, I feel like J-20's supersonic performance, which it prides itself in, might be tooooooo boggled down by its current engine. Is this true or might there be other way of looking at it?
Source of ws10 having 0.89 bypass ratio?
I googled......
Highest I ever heard was 0.78, which is close to the GE F110-129 BP ratio of 0.76 as they both essentially use the same core.
I do remember the 0.76 number from my search of bypass ratio a long time ago, I just went with this time's google search result. I think 0.76 should be the correct one. Thank you for pointing that out!
Anyone has any thoughts on the several questions I posted? I think those questions still hold true even with the 0.76 number. 0.76 is still way higher than those other engines. I don't know how to approach the questions I have in mind.
I do remember the 0.76 number from my search of bypass ratio a long time ago, I just went with this time's google search result. I think 0.76 should be the correct one. Thank you for pointing that out!
Anyone has any thoughts on the several questions I posted? I think those questions still hold true even with the 0.76 number. 0.76 is still way higher than those other engines. I don't know how to approach the questions I have in mind.
This post is a good explainer. I guess long story short it’s a bit more complicated than higher bypass ratio=no supercruise. There are other specific parameters involved, and it seems the actual key factor is overall pressure ratio to maintain high exhaust velocity. In other words for the same engine core a higher bypass ratio will have lower supercruise capability than a lower bypass ratio, but because overall pressure ratio is dictated by both the low and high pressure compressors as well as the inlet recovery pressure it’s hard to draw a hard relationship between exit velocity of your jet and your bypass ratio.
Any idea why China is so much further behind in civilian engines than military ones? Is it because the CCP views indigenous development of military tech as more important, and has therefore poured more resources into it?
And yeah engines are a weak point for China, so it's pretty impressive even in this area of relative weakness China manages to be the 4th-6th best country in the world, depending on how you look at it.
Semiconductor equipment is another obvious weak-point, but aside from that I think China is in the top 2 for all other frontier technologies, and in areas like 5g and big data lead the world. Maybe someone who is more knowledgeable can correct me.
Commercial engines emphasize a different set of performance parameters than military engines. Efficiency, reliability, durability, and availability matter a whole lot more, and these are things you need a different set of design approaches for. And in order to even get buyers you have to compete against the best designs already on the market, which are all very advanced, so you could come up with a design that’s 90% as good as what’s on the market and still not get sales, even if you make the engine cheaper, because those performance parameters like efficiency and reliability are all about reducing operation costs which are much greater than the item purchase cost. So if you can only do 90% as good as incumbents on engines there’s no money to be made developing these engines for commercial purposes. Plus without a commercial airplane designed to use the engine there isn’t even a market for a domestic commercial engine design, so even if you could make one it wouldn’t get used. All of these dynamics are very different from what drives development of military engines. That’s why the CJ-1000 only emerged after the C919 project was initiated.