Does this mean the CJ-1000A's development is at a more advanced stage than we used to think here?
Chinese Engine Development
- Thread starter jackbh
- Start date
At least two noteworthy things about this news:
1. The timing is about right if everything goes smoothly, but this being China's first commercial turbofan engine and as development process of C919 had demonstrated, delays are the norm rather than exceptions. It's a pleasant surprise that this news suggests that things are going well, at least for now.
2. The relatively publicized news and the emphasis on "accelerated push" for certification indicate some measure of confidence and urgency.
We're reading the tea leaves, of course. lol.
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The WS-20 is expected to have more thrust than the expected main production version of the CJ-1000A.
So if you could use a CJ-1000A derived engine on the Y-20, it would have to be some later variant.
Russia has a similar issue in that for the Il-76 you would need the PD-14M engine, since the regular PD-14 does not have enough thrust to replace the PS-90. And while the PS-90 and PD-14 are in production the PD-14M is not.
In China's case you would need the CJ-1000A engine core to enter production and some large CJ-1000A variant for the Y-20 or C919 stretch.
So if you could use a CJ-1000A derived engine on the Y-20, it would have to be some later variant.
Russia has a similar issue in that for the Il-76 you would need the PD-14M engine, since the regular PD-14 does not have enough thrust to replace the PS-90. And while the PS-90 and PD-14 are in production the PD-14M is not.
In China's case you would need the CJ-1000A engine core to enter production and some large CJ-1000A variant for the Y-20 or C919 stretch.
We hear this argument all the time, and maybe the reason it keeps getting repeated is because it doesn’t make a lot of sense, certainly not to me. Perhaps you can elaborate on it?
Why would a civilian engine not be good for military use?
They are more serviceable and efficient, and should be cheaper, while taking advantage of civilian research. What is it about these engines that make it unsuitable for military use?
Civilian aircraft engines have more stringent requirements in terms of quietness, fuel efficiency, safety and environment-friendliness which take longer and cost more to develop. If you happen to have mature civilian aircraft engine that meets you military requirements, then why not. Adapting some commercial aircraft to military uses are common practice, i.e., B737, B767.
In this particular case of fitting Y-20 with CJ-1000A, as explained Y-20 needs more thrust to reach its full potential and maximum payload. CJ-1000A itself is still under development and takes years to mature. Developing a version of CJ-1000A for Y-20 would take more time and more efforts, which is simply not worth it given WS-20 is already close to be operational. In any case, it's a theoretical question and any possibility at all is so far down the road.
Right, I was referring to the general practice.
So, basically, if a civilian engine has the thrust, it’s good to go, right?
I guess the root of my confusion, is in the ‘requirements’ of the military, we speak about it in this thread as if engine efficiency is not important as civilian, but I question this. Also, the long standing argument of noise, emissions and safety. these are all very desirable traits for a military engine imo.
Especially now that the PLA is going green.
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Well, the original question is about Y-20 using CJ-1000A, not the applicability of civilian engines in general.
Sure, if the Chinese aerospace industry had a mature civilian high bypass turbofan with sufficient performance for Y-20 that was already ready for it, then sure perhaps integrating it on Y-20 as its engine of choice would have been reasonable.
For example, the C-17 uses the same engine that was ultimately first applied for the civilian 757.
The Il-76's D-30 and now PS-90As were also originally first applied on civilian commercial airliner aircraft.
Other examples also exist.
However the Y-20 currently does not have a civilian engine that is mature and ready for it, and what they do have is WS-20 which is what Y-20 was designed for as its primary engine, and WS-20 has taken time to mature and be tested on the current Y-20B prototypes and soon to enter production (if not already began production) after a few years of flight testing.
Given all of that, even if we assume that CJ-1000A is equivalent to WS-20 in key performance parameters, what would the rationale for replacing Y-20B's WS-20 engines with CJ-1000A be, keeping in mind that CJ-1000A is still much less mature than WS-20 and that CJ-1000A's production will be prioritized for C919?
In other words, it's not just a matter of "let's use civilian engines if it meets requirements to share commonality and if it is more efficient"
Instead, you also need to ask:
- how mature is the new engine option compared to the existing engine option?
- does the new engine option have priorities elsewhere?
- how much time and money will it take to actually flight test and integrate the new engine option, and is it all even worthwhile?
For the PLA especially, in context of its still developing aero-engine industry, those are all rather relevant questions and arguably take precedence over simply whether a civilian engine meets requirements and is more efficient etc.