Chinese Engine Development

sunnymaxi

Captain
Registered Member
Only gossips I’ve heard is that it sacrificed MTBO to achieve certain fifth gen engine characteristics.
this is very misleading information.

advancement of WS-10 series still running with full pace. thanks to explosive growth in China's material/high end industry

in fact WS-10C engine in 2023 is different than WS-10C produced in 2020. coz Shenyang continue to upgrade components.
 
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siegecrossbow

General
Staff member
Super Moderator
this is very misleading information.

advancement of WS-10 series still running with full pace. thanks to explosive growth in China's material/high end industry

in fact WS-10C engine in 2023 is different than WS-10C produced in 2020. coz Shenyang continue to upgrade components.

In the end it is a fourth generation engine with a fourth generation core that needs to provide fifth generation performance in some aspects. There are compromises or there is no need to invest in WS-15.
 

latenlazy

Brigadier
In the end it is a fourth generation engine with a fourth generation core that needs to provide fifth generation performance in some aspects. There are compromises or there is no need to invest in WS-15.
Hmm. Not really how it works. If your material improvements are good enough you don’t need to make a tradeoff, or more specifically the margin of total performance gain is increased and you can improve in multiple parameters with no compromise or choose to focus along a single parameter with no improvement in others.

For context lot of the earlier abysmal mean-time to maintenance figures came from a combination of using older material production techniques like directionally solidified engine blades, and having extremely poor defect control in mass production of multiple parts. Simply moving to first generation single crystal blades and implementing more rigorous production quality controls of components likely accounted for the first round of (probably dramatic) mean-time to maintenance increases. In essence the first iteration of the WS-10 had terrible mean-time to maintenance mostly because it didn’t even meet the baseline production quality that would have been expected for the level of material technologies it used.

From there they’ve moved on to second and even third generation engine blades and other advanced materials (for example they’ve probably come a long way with components like ball bearing endurance), which can allow for concurrent improvement of both performance and meantime to maintenance. Factoring in how some mechanical failures are interdependent (for example if ball bearings are worse that translates to more wear on the shafts which then translates to mechanical strain on other parts which can then interact with factors like poor defect control on some other parts), you can sometimes get nonlinear improvements in reliability and maintenance schedule of the whole system in addition to allowing you to push other performance margins with just linear improvements in the performance of some components.

Relative to comparison with fifth generation engines, what this means is that rather than seeing a fourth gen engine reaching the lower threshold of fifth gen performance envelope as meaning the fourth gen engine must have *sacrificed* something, it’s probably more the case that the initial fifth gen engine performance margins on thrust and/or maintenance schedule that used to be deemed acceptable at the start of development has seen a substantial uplift. In other words, as the baseline quality of components, materials, and production process controls improve, it’s far more likely the case that the WS-15 will have better thrust and better mean time to failure at the start of its production than originally planned than it is that the WS-10C absolutely must be compromising mean-time to maintenance and reliability to reach the lower envelope of the WS-15’s thrust performance. Of course these two possibilities aren’t mutually exclusive, but looking at the basic material technologies available today to Chinese jet engine designs and matching them with what we see has been attained with the WS-10’s closest kin, the GE-F110, I don’t see any reason why it’s out of the realm of possibility that the WS-10C could reach lower end fifth gen thrust capabilities without compromise mean-time to maintenance.

Just as a simplified primer to help people think about how to assess jet engine performance claims, there are generally three separate factors of consideration to the mix of thrust and mean-time to failure performance margins. The first is engine cycle design, which is where the primary distinction between fourth gen and fifth gen engines are made (that’s things like the number of fan compressor and turbine stages, design around the mechanical and aerodynamics factors of compression, thermal and mechanical efficiency of the turbine, etc). Those are essentially questions of “how does this engine’s mechanical design work”. The second is the material quality, which determines “how hard and fast and hot can I run this engine, and at what point does running it at this level breaks things”. The third is your production process quality, which is basically “am I *actually* able to reach the performance levels in my product that the materials and cycle design should in theory allow, as demonstrated from my prototypes. The WS-10C could easily see drastic improvement from just the second and third factors without needing to match a 5th gen engine design in the first.

One more other way to see this is that your cycle design defines a bounded range of relative expected performance which can be lifted higher by material improvements. A 4th gen cycle design with first gen single crystal blades might get 13500 kg thrust with a mean-time to maintenance of 3000-4000 hours. Improve further to current state of the art materials and you might be able to hit 15000 kg of thrust at the same 3000-4000 hours, or 13500 kg with mean-time to maintenance of 5000-6000 hours. So the total potential performance range when factoring in different levels of material technology for a 4th gen cycle design could be said to be 13500-15000 kg thrust at 3000-6000 hours between mean times to maintenance. Meanwhile a 5th cycle design with first gen single crystal blades might start at 14500 kg of thrust for 3000-4000 hours of mean-time to maintenance. But with current state of the art materials it can hit 18000 kg of thrust at 3000-4000 hours of mean-time to maintenance.

Ultimately whether the WS-10C makes tradeoffs in maintenance schedule to hit higher thrust performance really depends on the particulars of the kind of technical details I laid out above, but given that the whole point of advancing material capabilities is to allow you to hit higher performance with fewer tradeoffs and given that even the rubric for 5th gen engine performance is not static and will move up with available material capabilities, I don’t think it’s a necessary conclusion to say that the WS-10C *must* be making sacrifices somewhere. Anyways sorry for the tldr, but I thought some of these thought exercises might be useful for future discussions.
 

HighGround

Junior Member
Registered Member
Does anybody know at what point an engine gets a new letter designation?

After reading this thread, the way I understand it is that there is continual development and improvements in between batches. I.E. the first batch of WS-10B is noticeably, perhaps even significantly, worse than the last WS-10B batch.

So what would prompt Shenyang to say that this engine is now a WS-10C? Are there specific milestones, or significant redesigns that prompts a change in designation?
 

siegecrossbow

General
Staff member
Super Moderator
Hmm. Not really how it works. If your material improvements are good enough you don’t need to make a tradeoff, or more specifically the margin of total performance gain is increased and you can improve in multiple parameters with no compromise or choose to focus along a single parameter with no improvement in others.

For context lot of the earlier abysmal mean-time to maintenance figures came from a combination of using older material production techniques like directionally solidified engine blades, and having extremely poor defect control in mass production of multiple parts. Simply moving to first generation single crystal blades and implementing more rigorous production quality controls of components likely accounted for the first round of (probably dramatic) mean-time to maintenance increases. In essence the first iteration of the WS-10 had terrible mean-time to maintenance mostly because it didn’t even meet the baseline production quality that would have been expected for the level of material technologies it used.

From there they’ve moved on to second and even third generation engine blades and other advanced materials (for example they’ve probably come a long way with components like ball bearing endurance), which can allow for concurrent improvement of both performance and meantime to maintenance. Factoring in how some mechanical failures are interdependent (for example if ball bearings are worse that translates to more wear on the shafts which then translates to mechanical strain on other parts which can then interact with factors like poor defect control on some other parts), you can sometimes get nonlinear improvements in reliability and maintenance schedule of the whole system in addition to allowing you to push other performance margins with just linear improvements in the performance of some components.

Relative to comparison with fifth generation engines, what this means is that rather than seeing a fourth gen engine reaching the lower threshold of fifth gen performance envelope as meaning the fourth gen engine must have *sacrificed* something, it’s probably more the case that the initial fifth gen engine performance margins on thrust and/or maintenance schedule that used to be deemed acceptable at the start of development has seen a substantial uplift. In other words, as the baseline quality of components, materials, and production process controls improve, it’s far more likely the case that the WS-15 will have better thrust and better mean time to failure at the start of its production than originally planned than it is that the WS-10C absolutely must be compromising mean-time to maintenance and reliability to reach the lower envelope of the WS-15’s thrust performance. Of course these two possibilities aren’t mutually exclusive, but looking at the basic material technologies available today to Chinese jet engine designs and matching them with what we see has been attained with the WS-10’s closest kin, the GE-F110, I don’t see any reason why it’s out of the realm of possibility that the WS-10C could reach lower end fifth gen thrust capabilities without compromise mean-time to maintenance.

Just as a simplified primer to help people think about how to assess jet engine performance claims, there are generally three separate factors of consideration to the mix of thrust and mean-time to failure performance margins. The first is engine cycle design, which is where the primary distinction between fourth gen and fifth gen engines are made (that’s things like the number of fan compressor and turbine stages, design around the mechanical and aerodynamics factors of compression, thermal and mechanical efficiency of the turbine, etc). Those are essentially questions of “how does this engine’s mechanical design work”. The second is the material quality, which determines “how hard and fast and hot can I run this engine, and at what point does running it at this level breaks things”. The third is your production process quality, which is basically “am I *actually* able to reach the performance levels in my product that the materials and cycle design should in theory allow, as demonstrated from my prototypes. The WS-10C could easily see drastic improvement from just the second and third factors without needing to match a 5th gen engine design in the first.

One more other way to see this is that your cycle design defines a bounded range of relative expected performance which can be lifted higher by material improvements. A 4th gen cycle design with first gen single crystal blades might get 13500 kg thrust with a mean-time to maintenance of 3000-4000 hours. Improve further to current state of the art materials and you might be able to hit 15000 kg of thrust at the same 3000-4000 hours, or 13500 kg with mean-time to maintenance of 5000-6000 hours. So the total potential performance range when factoring in different levels of material technology for a 4th gen cycle design could be said to be 13500-15000 kg thrust at 3000-6000 hours between mean times to maintenance. Meanwhile a 5th cycle design with first gen single crystal blades might start at 14500 kg of thrust for 3000-4000 hours of mean-time to maintenance. But with current state of the art materials it can hit 18000 kg of thrust at 3000-4000 hours of mean-time to maintenance.

Ultimately whether the WS-10C makes tradeoffs in maintenance schedule to hit higher thrust performance really depends on the particulars of the kind of technical details I laid out above, but given that the whole point of advancing material capabilities is to allow you to hit higher performance with fewer tradeoffs and given that even the rubric for 5th gen engine performance is not static and will move up with available material capabilities, I don’t think it’s a necessary conclusion to say that the WS-10C *must* be making sacrifices somewhere. Anyways sorry for the tldr, but I thought some of these thought exercises might be useful for future discussions.

Don’t shoot the messenger. I’m just repeating what I’ve heard from Weibo. It may or may not be accurate, hence “rumor has it”.
 
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