Chinese Engine Development

latenlazy

Brigadier
I realize that, and France has Snecma. You're saying that EJ200 is more advanced cus it has a >9 TWR? OK, that's a point but it's a 90kN engine and WS-10X can produce over 130kN depending on variant, possibly over 140kN on the latest variants so I wouldn't trade an EJ200 for a WS-10.... B. Neither France nor Britain has produced a high bypass engine with over 100kN from what I remember.
If we're talking about level of technology, the total thrust of an engine doesn't tell us much. The figures that tell us about technological level are T:W ratio, average HPC compression ratio, and turbine inlet temperature. Any country that can design an engine with the EJ200's specs can design a larger version in the class of the F119 or better. In fact, to some extent scaling up a smaller engine design is much easier than shrinking a larger one.
 
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manqiangrexue

Brigadier
If we're talking about level of technology, the total thrust of an engine doesn't tell us much. The figures that tell us about technological level are T:W ratio, average HPC compression ratio, and turbine inlet temperature. Any country that can design an engine with the EJ200's specs can design a larger version in the class of the F119 or better. In fact, to some extent scaling up a smaller engine design is much easier than shrinking a larger one.
I think you have it backwards. You can downsize easily but increasing the scale of an engine requires material and design improvements just like you can make a smaller airplane from a larger design but if you upscale a smaller design without changing it, it could fall apart from stress.

There are $40 RC toy "turbofan" engines with TWR in the teens. By your logic, you could upscale that and end up with a 200kN engine with TWR in the teens.

Honestly, if up-sizing was easy, they should stop making micro-improvements on the WS-10X and just upside it to at least 165kN for the interim J-20 engine.
 

Figaro

Senior Member
Registered Member
Uhhh...Britain, through EADS, has partial ownership of the EJ200. Technologically speaking the EJ200 is definitely more advanced than the WS-10X, and at least from what we know so far it may even be a bit more advanced than the WS-15
If the EJ-200 is "a bit more advanced" than the WS-15 and the 2025 rumor is true, then China's engine industry is in serious trouble ... if that were the case, the Chinese engine sector would be 40 years behind the West's
 

latenlazy

Brigadier
I think you have it backwards. You can downsize easily but increasing the scale of an engine requires material and design improvements just like you can make a smaller airplane from a larger design but if you upscale a smaller design without changing it, it could fall apart from stress.

There are $40 RC toy "turbofan" engines with TWR in the teens. By your logic, you could upscale that and end up with a 200kN engine with TWR in the teens.

Honestly, if up-sizing was easy, they should stop making micro-improvements on the WS-10X and just upside it to at least 165kN for the interim J-20 engine.
Increasing the size of the engine also means increased thermal efficiency, and jet engines are fundamentally function by drawing more work out of thermal energy. With the EJ200, you could ease up on some of the mechanical demands when upsizing and still get an F119 class engine. Anyways, I did suggest that there was a limit to which this logic holds, but building an F119 class or better engine out the technology in the EJ200 falls well within the parameters of that logic. Also, RC "turbofan" engines aren't actual turbofan engines.

They very well could have built an upsized WS-10, but then they would need a bigger plane. The novelty of the idea very quickly defeats the point.
 

manqiangrexue

Brigadier
Increasing the size of the engine also means increased thermal efficiency, and jet engines are fundamentally function by drawing more work out of thermal energy. With the EJ200, you could ease up on some of the mechanical demands when upsizing and still get an F119 class engine. Anyways, I did suggest that there was a limit to which this logic holds, but building an F119 class or better engine out the technology in the EJ200 falls well within the parameters of that logic. Also, RC "turbofan" engines aren't actual turbofan engines.

They very well could have built an upsized WS-10, but then they would need a bigger plane. The novelty of the idea very quickly defeats the point.
Well the J-20 does have a kaboose made for a slightly larger engine than WS-10X (WS-15) so for a certain amount, you could upscale say 15% for 15% more thrust without needing to expand the jet, which is no trivial amount. That they didn't makes me think that you cannot upscale engines without material/technology breakthrough.

Anyway, as with all material, with a linear increase in size, strength increases by ^2 while weight increases by ^3, which means up-scaling anything results in the strength-weight ratio to decrease. Because of this, I just don't think that you can upscale without material enhancements otherwise you would exceed the max stress-bearing parameters.

Anyway, those are my thoughts; is there any evidence of this happening? Has anyone scaled an engine up before without material/technological advancements?
 

latenlazy

Brigadier
If the EJ-200 is "a bit more advanced" than the WS-15 and the 2025 rumor is true, then China's engine industry is in serious trouble ... if that were the case, the Chinese engine sector would be 40 years behind the West's
And that is why some people make that argument. However, consider this. The WS-15 was first spec'ed out in the early 2000s using that period's technological base. It seems unlikely to me that as China's technological knowhow has improved through the years the WS-15's development team wouldn't be continuously folding in as much new knowledge and new technology as they could without having to go back to a full clean sheet or risking major disruptions in the program. Ultimately though, there's a limit to how much extra advancement you can wring out of a continuously revised concept that is a decade or two old. It may be that when China begins work on their next generation engine its technological development won't start where a completed WS-15 left off but wherever the technological base is when they start, which could be some steps ahead. It may even be that such a program could start before the WS-15 is complete. This is rather typical of situations where the technological base is moving faster than the product cycle it's being utilized in. If there really is an improved iteration of the WS-15 that is already being worked on in parallel to the current development of the WS-15 as some rumours might suggest, this would be suggestive of exactly this phenomena. I'm not saying that this is actually the case of course, just that this would be the more optimist scenario.
 

latenlazy

Brigadier
Well the J-20 does have a kaboose made for a slightly larger engine than WS-10X (WS-15) so for a certain amount, you could upscale say 15% for 15% more thrust without needing to expand the jet, which is no trivial amount. That they didn't makes me think that you cannot upscale engines without material/technology breakthrough.
The limit isn't the kaboose. It's the intake. And the point isn't to get 15% more thrust through upscaling, but to get that 15% increase in thrust to weight ratio through upscaling, which could require a lot more than a 15% increase in size. This is all academic of course. There are a lot of limiting factors to the logic, and it wasn't my intention to make a straight extrapolation with this point.
Anyway, as with all material, with a linear increase in size, strength increases by ^2 while weight increases by ^3, which means up-scaling anything results in the strength-weight ratio to decrease. Because of this, I just don't think that you can upscale without material enhancements otherwise you would exceed the max stress-bearing parameters.
Obviously you would need material enhancements to maintain the same level of mechanical performance for a larger engine, but my point is that with a bigger engine you can get more performance with less demanding mechanical performance.

Also, keep in mind that just because EADS hasn't developed a larger engine that shares the EJ200's performance parameters, that doesn't tell us that they couldn't. They have never needed to because their customers have never asked for a heavy weight fighter engine.
 

ougoah

Brigadier
Registered Member
If the EJ-200 is "a bit more advanced" than the WS-15 and the 2025 rumor is true, then China's engine industry is in serious trouble ... if that were the case, the Chinese engine sector would be 40 years behind the West's

40 years isn't all that long in the highest league of engine technologies. About a generation and a half or so? USA, UK, France, and Russia. The only nations with corporations that can produce high quality and bleeding edge technology engines. Only USA and Russia have high thrust military turbofans. So being able to build WS-10x and WS-15 is impressive enough for a country that industrialised very late compared to these nations.
 

Figaro

Senior Member
Registered Member
40 years isn't all that long in the highest league of engine technologies. About a generation and a half or so? USA, UK, France, and Russia. The only nations with corporations that can produce high quality and bleeding edge technology engines. Only USA and Russia have high thrust military turbofans. So being able to build WS-10x and WS-15 is impressive enough for a country that industrialised very late compared to these nations.
Actually, China also has the ability to produce high thrust turbofans. But my response to Latenlazy was that if the WS-15 was indeed inferior to the 80s EJ-200, then there is a huge problem. A generation and a half gap is huge in the modern day aviation industry .... and imagine that gap in 2025. The WS-15 Should at the very least be on the same level as EJ-200 or M88-3 if it wants to close the engine gap. How will the WS-15 compare with an upgraded F-135 in the future then? Maybe we are relying too heavily on a 2004 academic paper but if the WS-15 has the exact same parameters ... then the wait will be troubling. We can only hope that it is because of technical improvements that the WS-15 has been delayed ... the WS-15 dev cycle should be faster than that of the WS-10.
 
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ougoah

Brigadier
Registered Member
Oops sorry. I was meant to include China in that list of high thrust turbofans. Three players in that field. Can do is not the same as has done so WS-10x is still a real life engine that is being used while France and UK will need to develop a high thrust engine if their future fighter requires one. I think other military areas are just as if not more important than turbofans for fighters. 1.5 generations and/or 30-40 years behind the very latest and greatest isn't really that bad. An M1 Garand can be effective and kill an enemy soldier as dead as an XM-8 despite being many many generations and about a century behind. There are many military industry areas where China is ahead of Europe in technology as well as application. I don't think rushing these projects and hoping for big news on developments everyday is justified.
 
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