Chinese Engine Development

Re: Shenyang J-31 Fighter

thunderchief said:

China already has new engine designs (WS-13, WS-15, WS-10 etc ) ... All they need is blade technology and they are good to go - no need to import Russian engines, then to improve blades , re-test them and only after that install them in aircraft .

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From what materials I could get my hands on and from what I can deconstruct with what we know about China's engine program, I would actually wager that the blade technology was ready before the engine designs were. After all, in order to have built and tested the core for the WS-15 in 2006 they would have had to have specs on the HP section of the engine first, which would include engine blades. It's not like if you have an engine design and the technology to manufacture the right blades for the design you could just slap them all together and make that a finished product. The engine's entire design is a cohesive system that needs testing, re-testing, and sometimes adjustments and modifications. That's not the case with the blade technology. Engine blades are simply parts which have certain performance specifications. With the engine blades you could, for the most part, just plug and play with older designs. At the end of the day the distinction comes down to whether you're making modifications to an existing design or coming up with an entirely new one. The former is vastly easier and requires less time to do.

Re: Shenyang J-31 Fighter

nemo said:

Why invent the wheel when you don't have to? Besides, WS-13 is only used for exports-- none of the aircraft used by PLA uses that. So instead of spending time and effort to create a new engine for low production aircraft (by PLA standard), you might as well just license an existing engine and and start from there.

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As far as I know, China does not produce any of RD-33 clones , with or without license . On the other hand, need for such engine exists . PAF plans to introduce more then 100 of JF-17 , and China plans to build aircraft like J-31 and various drones . So if they could they would make something similar to RD-33 or better .

nemo said:

Russian actually used a more permissive criteria to calculate trust to weight ratio. If you actually use the same criteria, then the calculated thrust to weight ratio would actually be somewhat the same as WS-10. But that's besides the point. WS-10 also have higher dry thrust (non-afterburning) thrust than AL-31, and that's more useful operationally.

If you tries to improve RD-33, you only modifies part of the engine anyway. I fail to see how the new parts weights so much that thrust to weight ratio fails to improve.

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If you want to improve thrust of the engine (same dimensions , roughly same weight) you need better materials. There is no other way. Yes , you could introduce measures like FADEC to improve efficiency etc ... but for increased thrust you simply need increased temperature .

I'm not privy to Chinese or Russian technological secrets, but looking at the specs of various engines we have in public domain , I would say that Al-31 and RD-33 use same technology , and that WS-10A is somewhere near that . My conclusion is that with current technological level China could not improve thrust of RD-33 , especially not to a level which would give JF-17 better then 1 T/W ratio when fully loaded (92kN or even 98 claimed by some people)

Re: Shenyang J-31 Fighter

latenlazy said:

From what materials I could get my hands on and from what I can deconstruct with what we know about China's engine program, I would actually wager that the blade technology was ready before the engine designs were. After all, in order to have built and tested the core for the WS-15 in 2006 they would have had to have specs on the HP section of the engine first, which would include engine blades. It's not like if you have an engine design and the technology to manufacture the right blades for the design you could just slap them all together and make that a finished product. The engine's entire design is a cohesive system that needs testing, re-testing, and sometimes adjustments and modifications. That's not the case with the blade technology. Engine blades are simply parts which have certain performance specifications. With the engine blades you could, for the most part, just plug and play with older designs. At the end of the day the distinction comes down to whether you're making modifications to an existing design or coming up with an entirely new one. The former is vastly easier and requires less time to do.

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If they had blades and some other parts like engine casings solved in 2006., they would have engine by now .

My guess (and it is only guess) is that they managed to build an test core of the engine at given parameters (temperature, trust) , but they didn't achieve desired endurance. In other words, WS-15 was running fine for few minutes, maybe even few hours, but later when they inspected the engine they probably found some cracks or other damage .

Therefore, engine is most likely conceptually ready by now, but it is not ready for operational service .

Re: Shenyang J-31 Fighter

thunderchief said:

If they had blades and some other parts like engine casings solved in 2006., they would have engine by now .

My guess (and it is only guess) is that they managed to build an test core of the engine at given parameters (temperature, trust) , but they didn't achieve desired endurance. In other words, WS-15 was running fine for few minutes, maybe even few hours, but later when they inspected the engine they probably found some cracks or other damage .

Therefore, engine is most likely conceptually ready by now, but it is not ready for operational service .

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If they didn't have the parts and blades in 2006 they wouldn't have been able to begin testing! (There's also evidence that they had already developed blades that were ready for an F119 class engine before they began core testing for the WS-15).

And no. Given what we know from various leaks and rumours through the years it seems pretty clear to me that the engine core underwent a complete and thorough testing of all parameters, and probably performed fine. There was talk a few years back of the engine core finishing platform and then high altitude testing. Coupled with the most recent news item we have from the start of 2014 that they began building a full prototype suggests to me that they are not merely stuck at the concept level or that engine core testing went bad. If they were encountering the kinds of problems with the engine core you're suggesting then it's unlikely that we would have heard about different stages in the engine testing, and VERY unlikely that they would be confident enough to build a complete engine for testing.

I hope you're not suggesting that simply having a conceptually sound design with the properly spec'd parts immediately leads to operational service. If you do a quick study of any new jet engine design you'd find that all engine designs have ridiculously long lead times from design validation to prototype testing to operational service.

This is kinda old but DefenceWorld.net claims that tests for the WS-10 and the WS-15 were completed in Tibet sometime in September.

"China recently tested what is believed to be the WS-10 (Taihang) and WS-15 (Emei) engines which the carrier-borne aircraft J-15 and the stealth fighter J-20 are likely to be equipped it. Test Flight Center of Aviation Industry Corporation of China (AVIC) successfully completed the first takeoff-and-landing test flight of the fighter planes recently on the plateau in Qinghai province, the Voice of China reported. This test flight is the first high altitude test for two types of engines in installed status.

During the test flight, the test flight team overcame adverse factors such as high altitude anoxia and strong ultraviolet irradiation, avoided the impact of thin air, low pressure and small inlet flow on the engines, and successfully completed such tests as the power start tests on the plane and ground, the “cold” and “hot” starts and continuous starts of the engines, the acceleration and deceleration performance, and the performance quality inspection of afterburner, according to the report."



Is there a "Voice of China' newspaper or did it mean Voice of Russia?

Tyloe said:

This is kinda old but DefenceWorld.net claims that tests for the WS-10 and the WS-15 were completed in Tibet sometime in September.

"China recently tested what is believed to be the WS-10 (Taihang) and WS-15 (Emei) engines which the carrier-borne aircraft J-15 and the stealth fighter J-20 are likely to be equipped it. Test Flight Center of Aviation Industry Corporation of China (AVIC) successfully completed the first takeoff-and-landing test flight of the fighter planes recently on the plateau in Qinghai province, the Voice of China reported. This test flight is the first high altitude test for two types of engines in installed status.

During the test flight, the test flight team overcame adverse factors such as high altitude anoxia and strong ultraviolet irradiation, avoided the impact of thin air, low pressure and small inlet flow on the engines, and successfully completed such tests as the power start tests on the plane and ground, the “cold” and “hot” starts and continuous starts of the engines, the acceleration and deceleration performance, and the performance quality inspection of afterburner, according to the report."

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Is there a "Voice of China' newspaper or did it mean Voice of Russia?

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The original report only specified that two engines completed high altitude take off tests. It made no mention to the actual identity of those engines.

Re: Shenyang J-31 Fighter

latenlazy said:

If they didn't have the parts and blades in 2006 they wouldn't have been able to begin testing! (There's also evidence that they had already developed blades that were ready for an F119 class engine before they began core testing for the WS-15).

And no. Given what we know from various leaks and rumours through the years it seems pretty clear to me that the engine core underwent a complete and thorough testing of all parameters, and probably performed fine. There was talk a few years back of the engine core finishing platform and then high altitude testing. Coupled with the most recent news item we have from the start of 2014 that they began building a full prototype suggests to me that they are not merely stuck at the concept level or that engine core testing went bad. If they were encountering the kinds of problems with the engine core you're suggesting then it's unlikely that we would have heard about different stages in the engine testing, and VERY unlikely that they would be confident enough to build a complete engine for testing.

I hope you're not suggesting that simply having a conceptually sound design with the properly spec'd parts immediately leads to operational service. If you do a quick study of any new jet engine design you'd find that all engine designs have ridiculously long lead times from design validation to prototype testing to operational service.

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They did have blades in 2006 and they did full testing . But all didn't went well. IMHO, they probably found out that blades (or some other parts) made with materials then available would not endure operational service . In other words, engine could run some time but it could also disintegrate in mid-air. That is not a failure , it is just a stage in development . Real failure would be to completely solve problem of the blades (hardest part) and then to wait 8 long years to build prototype of the engine meanwhile importing engines from other countries . I don't think China would allow that . Instead, if the rumors about new WS-15 prototype are true, they probably want to test new turbine blades (among other things) made from other materials.

Re: Shenyang J-31 Fighter

thunderchief said:

They did have blades in 2006 and they did full testing . But all didn't went well. IMHO, they probably found out that blades (or some other parts) made with materials then available would not endure operational service . In other words, engine could run some time but it could also disintegrate in mid-air. That is not a failure , it is just a stage in development . Real failure would be to completely solve problem of the blades (hardest part) and then to wait 8 long years to build prototype of the engine meanwhile importing engines from other countries . I don't think China would allow that . Instead, if the rumors about new WS-15 prototype are true, they probably want to test new turbine blades (among other things) made from other materials.

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You seem rather sure it didn't go well in 2006 and furthermore it hasn't gone well since. Evidence?

Also it seems like you're conflating engine core testing with a full prototype. If they really did have problems with testing at the engine core phase it seems unlikely they would move from core to full prototype if the issues hadn't been resolved.

Re: Shenyang J-31 Fighter

latenlazy said:

You seem rather sure it didn't go well in 2006 and furthermore it hasn't gone well since. Evidence?

Also it seems like you're conflating engine core testing with a full prototype. If they really did have problems with testing at the engine core phase it seems unlikely they would move from core to full prototype if the issues hadn't been resolved.

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Evidence - 8 years have passed and what we have ? Nothing , except rumors about prototype . Compare that with development cycles of other engines (American, Russian, and even Chinese like WS-10) .

Jet engine core consists of turbines and combustion chamber, and these are parts that endure most of the heat and pressure. This i really core of the engine, and core of the problem . All other parts are peripheral and comparatively simple to design and build, especially if you have experience with other engines . IMHO, they did have issues with core, and that delayed whole program, but from 2006 some progress have been made . Maybe not enough to build ready-for-service engine, but certainly enough to run complete engine tests. After all, engine blades, like other parts , have service life and mean time to failure . If the service life of whole engine comes between 10h and 20h , that is certainly not good enough for operational service, but it is more then enough to run comprehensive tests .

Re: Shenyang J-31 Fighter

thunderchief said:

Evidence - 8 years have passed and what we have ? Nothing , except rumors about prototype . Compare that with development cycles of other engines (American, Russian, and even Chinese like WS-10) .

Jet engine core consists of turbines and combustion chamber, and these are parts that endure most of the heat and pressure. This i really core of the engine, and core of the problem . All other parts are peripheral and comparatively simple to design and build, especially if you have experience with other engines . IMHO, they did have issues with core, and that delayed whole program, but from 2006 some progress have been made . Maybe not enough to build ready-for-service engine, but certainly enough to run complete engine tests. After all, engine blades, like other parts , have service life and mean time to failure . If the service life of whole engine comes between 10h and 20h , that is certainly not good enough for operational service, but it is more then enough to run comprehensive tests .

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Absence of evidence is not evidence of absence. Just because we have been spoiled with comprehensive leaks with some programs does not mean we should expect comprehensive leaks of all programs. This is especially the case with Chinese engines. You mention how much we now know about the Taihang, but the Taihang was pretty incognito for most of its development. Only when they were ready for production did we actually see the engine. (Of course ready for production should be put in quotes, because the program had hiccups after that point). If we follow the same pattern of leaks as the WS-10, we actually should not expect any visual confirmation of the WS-15 until the engine is on the tail end of testing and is being readied for production. If the rumour that they've only just built a complete prototype for testing, we should still not expect to see photos of the engine for another 3 to 5 years.