COMAC C919


test1979

New Member
Registered Member
WS-20 is not designed to civilian standard. There is a huge gap in reliability, availability, maintainability and serviceability of WS-20 vs CJ-1000A. The requirement for fuel burn rate is a lot higher for CJ-1000A than WS-20.

Let's put it this way. If WS-20 equipped C919 is available 90% of time vs a Leap-1C equipped C919 being available 99.5% of time, then no airline would be picking WS-20 engine unless as a favor to the government.

Airlines have really low margin. A 5 to 10% difference in fuel burn and having to keep around 4 times the number of spare aircraft to operate a schedule reliably will bankrupt an airline.

Again, I would really caution putting a military engine on C919 when it will put undesirable attention on the C919 program. You don't want Western suppliers of C919 to drop out when C919 has yet to be certified anywhere.
the withdrawal of international partners is a very real threat. Looking at what happened to Hua wei, no international partner dared to resist the U S ban.
 

test1979

New Member
Registered Member
WS-20 is not designed to civilian standard. There is a huge gap in reliability, availability, maintainability and serviceability of WS-20 vs CJ-1000A. The requirement for fuel burn rate is a lot higher for CJ-1000A than WS-20.

Let's put it this way. If WS-20 equipped C919 is available 90% of time vs a Leap-1C equipped C919 being available 99.5% of time, then no airline would be picking WS-20 engine unless as a favor to the government.

Airlines have really low margin. A 5 to 10% difference in fuel burn and having to keep around 4 times the number of spare aircraft to operate a schedule reliably will bankrupt an airline.

Again, I would really caution putting a military engine on C919 when it will put undesirable attention on the C919 program. You don't want Western suppliers of C919 to drop out when C919 has yet to be certified anywhere.

So, you're saying that you want WS-20 to be used for a "domestic civil" C919?

Let's pretend that WS-20 is competitive with old CFM-56s for civilian specific parameters.

And let's take the 2027 date as when CJ-1000A is in service for C919.


Integrating WS-20 onto C919 will still take time and consume aerospace resources -- it would take at least 2-3 years. Structural redesign, integration, flight testing would all have to be done. This is on top of replacement of other domestic subsystems for C919 that would be occurring concurrently.

So, a WS-20 equipped C919 airframe likely would not be ready until 2024-2025. That's a difference of 2-3 years between a WS-20 equipped C919 and a CJ-1000A equipped C919.
Is that three year gap really that important to have a WS-20 equipped C919, considering it would almost immediately be replaced in production by the CJ-1000A equipped C919 afterwards, given CJ-1000A would be far superior to WS-20 for the civilian airliner flight profile?

Heck, even if WS-20 equipped C919s continue in service for a number of years, is it really worth supporting two domestic C919 variants in the world into the future, simply so China can have a "domestic C919" flying a few years earlier?



And remember, all of this is assuming that the WS-20 is sufficiently worthwhile for civilian airlines to operate and "affordable" for them to operate, which in reality may not be the case at all.


So no, I don't think integrating WS-20 onto C919 as a "domestic variant" for the civilian market is sensible. I believe it would be a waste of resources.
The only way in which a domestic variant of C919 using WS-20 would make sense, is if the PLA really wanted a domestic C919 variant for military purposes only, and were unwilling to wait for the domestic civil C919 variant powered by CJ-1000A.
CJ1000 has some huge risks, look up its supplier list and you'll find companies from Japan, Germany, and France on the list. I don't think these companies dare to defy the US ban. In fact, look up Chinese domestic news after 2018, and you will find that China is silently preparing to replace these suppliers. For example, a domestic supplier obtained the same composite material supply qualification as Japan's Toray in 2021 after 4 years of testing. But these efforts will take time and will significantly delay the CJ1000's timeline for completing testing in 2027.
 

Bltizo

Lieutenant General
Staff member
Super Moderator
Registered Member
In this respect, CJ1000 and WS-20 are the same, SF-A was initially considered as the engine of C919. If the WS-20 needs to restart testing on the C919 for 2.3 years, the same is true for the CJ1000 after the forensics are completed. It takes 2 or 3 years of testing to replace the c919 with the CJ1000. That means it won't be put into use until at least 2030. And this requires a major premise. CJ1000 must be completed strictly according to COMAC's schedule, but COMAC's record has been poor in this regard.

If you want to make a case for developing a domestic C919 variant with WS-20, that is fine, but you need to understand that it is not a clear and cut case of "just go for it".

The rational for developing a C919 variant with WS-20, is dependent on a range of factors, such as:
- When a C919 with CJ-1000A is expected to emerge
- The actual performance of a C919 with WS-20 in the first place
- The priority of having a domestic C919 variant in the first place
- The availability or non-availability of purchasing foreign narrow body airliners
- The importance of having a steady stream of narrow body airliners in context of the national geopolitical strategy



There are a few circumstances I can see where developing a C919 with WS-20 intended for the civilian market may be necessary.

For example, if CJ-1000A is simply unable to bear fruit until after 2035, and if for example the US and Europe tomorrow cut China off entirely from purchasing narrow body airliners, parts, engines and support wholesale, resulting in a fixed expiry date of China's national narrow body airliner fleet that has to be plugged with a similar aircraft, as judged to be important by national leadership.
Then sure, C919 with WS-20 is certainly much better than nothing.

But other than that, I don't see a scenario whereby C919 waiting for CJ-1000A is unacceptable and where integration of WS-20 is somehow vital to the survival of the aircraft program.
 

lcloo

Senior Member
Relax people, Airbus and Boeing are not going to cut off supply of airplanes and parts to China unless they want to go into bankruptcy. What they want is dominance and money. They may want to block COMAC's progress but they won't want to destroy Chinese airlines market. Chinese airlines market is far far too large and important.

These companies have strong influences in their governments, they won't want their golden goose to be slaughtered.
 

test1979

New Member
Registered Member
Relax people, Airbus and Boeing are not going to cut off supply of airplanes and parts to China unless they want to go into bankruptcy. What they want is dominance and money. They may want to block COMAC's progress but they won't want to destroy Chinese airlines market. Chinese airlines market is far far too large and important.

These companies have strong influences in their governments, they won't want their golden goose to be slaughtered.
Yes, the supply of planes and parts may not be stopped.
But for C919 it's another story, why am I so worried about US sanctions?
The reason is that my friend of COMAC gave me bad information, why did COMAC have a delay after it clearly announced in 2020 that the test will be completed in 2021? Not because of COV-19, but some partners have started to delay the technical support that should be given.
 

Bltizo

Lieutenant General
Staff member
Super Moderator
Registered Member
Yes, the supply of planes and parts may not be stopped.
But for C919 it's another story, why am I so worried about US sanctions?
The reason is that my friend of COMAC gave me bad information, why did COMAC have a delay after it clearly announced in 2020 that the test will be completed in 2021? Not because of COV-19, but some partners have started to delay the technical support that should be given.

Relax people, Airbus and Boeing are not going to cut off supply of airplanes and parts to China unless they want to go into bankruptcy. What they want is dominance and money. They may want to block COMAC's progress but they won't want to destroy Chinese airlines market. Chinese airlines market is far far too large and important.

These companies have strong influences in their governments, they won't want their golden goose to be slaughtered.


So, the reason the prospect of Airbus and Boeing cutting off their supply of aircraft and parts and support is raised is because I wanted to answer test1979's question/scenario -- "under what circumstances would it make sense for China to pursue development of a WS-20 powered C919".

I think that question needs to be considered carefully.
 

TerraN_EmpirE

Tyrant King
Do not see how C919 can serve as a military transport.

Essentially all military transports, whether jet or turboprop powered, utilize high wing design for the fuselage to "hug" the ground for ease of roll in and roll out of military vehicles and other cargos. Also turboprop enables take off and landing on rough runways without worrying about sucking in debris like a jet engine would.
I know jumping in a little late here. Not every mission demands a STOL transport which is what you are describing. Particularly in the special mission class. But there have still been conventional airliners based platforms used as transports for military logistics. KC10, KC135, KC767, A310 MRTT, A330MRTT. Now generally these are larger aircraft than the 919 but the Israelis have proved that a smaller Buisness jet could tank. Also they have personal and ISO container.
Primarily though it’s special mission.
@Bltizo was nice enough to lay out a short list.
Y-8/9 special mission aircraft do and more:
- AEW&C
- MPA
- standoff EW/ECM
- ELINT, SIGINT
- Airborne command post
- Air to ground radar/ISR platform
This nicely sums up a good deal of potential missions almost all of them could if so chosen be done by a C919 sized airframe and are in fact.
E7 AEW&C
P8 and P1
EC37
Tu214R
Tu214Pu
R99
I would add to this list with the following potential missions.
-Communications relay for foreign visits by Head of state/Head of Government.
-Strategic weapons command node.
-VVIP aircraft, particularly Head of state/Head of government and successors. Whom may need to be evacuated in the event of a national emergency. Yes yes most everyone wants the big jet but a lot of nations actually use smaller ones. Even the 737 A320 size or smaller. Especially for shorter range trips or in cases where they are not leaving the homeland.
-aeromedical transport aircraft think flying hospital ship.

Now the engine debate. C929 seems like at best it’s going to be delayed as Comac reorganized the program at worst DOA.
C919 has just started its qualifying. It makes more sense to stay the course now. Even if they produce military iterations it would make more sense to use the already programmed CJ than Ws. The investment cost to put new engines under the wing isn’t cheap. The CJ has the best potential of actually selling and getting built.
 

tphuang

Brigadier
VIP Professional
Registered Member
the withdrawal of international partners is a very real threat. Looking at what happened to Hua wei, no international partner dared to resist the U S ban.

That has no relevance on whether or not ws20 is acceptable for civilian aircraft.

If you want something to achieve civilian requirements, then you have to develop one as such from ground up. That's why they have cj1000.

Keep in mind that china gets tremendous knowledge from working with the western aerospace industry. Even if things get delayed, they learn a lot from how to design an aircraft that can get certified, supply chain management, design philosophies and many other things. These are things they need to learn as they are developing their own supply chain.

There is a couple of articles on this.
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keep in mind there is a lot of politics going on here. For example, China did not approve 737 MAX to fly again until December of last year. That was a huge sticking point in aerospace industry.
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There is no evidence at this point that C919 cannot proceed with the current suppliers. They are just taking longer time and need more testing.
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Should C919 work toward a fully domestic supply chain? Of course it should. But developing a full domestic supply chain for something like modern airliner takes a long time. And putting military suppliers into C919 program will simply make things more complicated.
 

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