COMAC C919

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weig2000

Captain
supersnoop said:
I remember kicking off this exact discussion some time ago.
The talk kind of died off because:
1. Not happening without CJ-1000
2. If the military wanted to make it happen due to national need, it could have develop a parallel project with all Chinese subsystems, but probably the cost is not justified
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That was then, this is now.

1. CJ-1000A is making steady progress and should be ready before 2025. They may have to get it ready for prime time anyway because LEAP-1C's availability in future might be in danger.

2. Not sure about the argument, exact opposite is true now actually. Why start a new project when you have C919. If previously the idea is to utilize/leverage foreign subsystems as much as possible and carefully protect the civilian C919 from the military purpose, now the prospect of C919 being sanctioned is getting real by the day. Which means that you need to accelerate any Plan B or import substitution programs for C919 now, which further means that that concerns or prohibition for adapting C919 for military purpose are no longer there.
 
T

test1979

Junior Member
Registered Member
supersnoop said:
I remember kicking off this exact discussion some time ago.
The talk kind of died off because:
1. Not happening without CJ-1000
2. If the military wanted to make it happen due to national need, it could have develop a parallel project with all Chinese subsystems, but probably the cost is not justified
Click to expand...
Why not use the WS-20 instead? Similar thrust to cj-1000, and unified logistics with y-20?
 
tphuang

tphuang

Lieutenant General
Staff member
Super Moderator
VIP Professional
Registered Member
The availability and reliability requirements for civilian turbofan engines are a lot higher than large bypass military turbofan engine. The other thing is that China already has a reputation of mixing civilian with military programs that has had an adverse effect on the sales prospect of its civilian aircraft. You really want to keep the two separate if you want to improve the competitiveness of your domestic aerospace industry. Until China establish itself in the civilian aerospace market, this will always be something hanging over the head of COMAC.

As such, let's keep military transport platform and civilian airliners separate. The Y-9 project is doing well. They can always keep improving the reliability and fuel savings on their turboprop engines. They can continually iterate and improve the performance of Y-9.

Keep in mind that projects like CJ-1000 and CJ-2000 can get assistance for international partners. That's not an opportunity afforded to WS-20 development. There are industrial and technological reasons to keep civilian and military projects separate.
 
Maikeru

Maikeru

Captain
Registered Member
tphuang said:
The availability and reliability requirements for civilian turbofan engines are a lot higher than large bypass military turbofan engine. The other thing is that China already has a reputation of mixing civilian with military programs that has had an adverse effect on the sales prospect of its civilian aircraft. You really want to keep the two separate if you want to improve the competitiveness of your domestic aerospace industry. Until China establish itself in the civilian aerospace market, this will always be something hanging over the head of COMAC.

As such, let's keep military transport platform and civilian airliners separate. The Y-9 project is doing well. They can always keep improving the reliability and fuel savings on their turboprop engines. They can continually iterate and improve the performance of Y-9.

Keep in mind that projects like CJ-1000 and CJ-2000 can get assistance for international partners. That's not an opportunity afforded to WS-20 development. There are industrial and technological reasons to keep civilian and military projects separate.
Click to expand...
Military aircraft are doing their job even if they're just sat on the tarmac, i.e. deterrence. They only get heavy usage in wartime or major exercises, generally they spend ~10% of time actually flying, depending on type. This is why you get aircraft like B52 and KC135 operating for 60+ years.

Civil airliners are used much, much more intensively, maybe 70-80% of the time they're actually in the air paying back their capital cost. Engines and airframes need to be able to handle such intense usage.
 
T

test1979

Junior Member
Registered Member
dengyeye said:
I believe military engines are a completely different thing to civilian engines, which must undergo more intense testing.
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The ws-20 was designed to civilian standards, and its civilian version, the SF-A, was once considered as a domestic engine for the C919. The reason for giving up is that the fuel consumption rate is not as good as the economy problem caused by the CJ1000.
Considering that cj000 will take time, and the possible embargo imposed by the United States, WS-20 is a good transition.
 
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test1979

Junior Member
Registered Member
tphuang said:
The availability and reliability requirements for civilian turbofan engines are a lot higher than large bypass military turbofan engine. The other thing is that China already has a reputation of mixing civilian with military programs that has had an adverse effect on the sales prospect of its civilian aircraft. You really want to keep the two separate if you want to improve the competitiveness of your domestic aerospace industry. Until China establish itself in the civilian aerospace market, this will always be something hanging over the head of COMAC.

As such, let's keep military transport platform and civilian airliners separate. The Y-9 project is doing well. They can always keep improving the reliability and fuel savings on their turboprop engines. They can continually iterate and improve the performance of Y-9.

Keep in mind that projects like CJ-1000 and CJ-2000 can get assistance for international partners. That's not an opportunity afforded to WS-20 development. There are industrial and technological reasons to keep civilian and military projects separate.
Click to expand...
Judging from what has happened to Huawei, it is extremely dangerous to rely on the help of international partners to solve technical problems. No country is willing to resist US sanctions‘s bans for China.
 
S

supersnoop

Major
Registered Member
Jet's biggest advantage vs. Turboprop is speed. If this was an absolute critical necessity, then PLA would undertake whatever risk/cost required to militarize the C919 including using WS-20.

A good example is the WZ-10 development which the airframe was contracted out to Kamov to reduce risk and development time, and utilized Canadian/American engines to get started even knowing that this would be a dead end.
 
A

Atomicfrog

Major
Registered Member
Maikeru said:
Military aircraft are doing their job even if they're just sat on the tarmac, i.e. deterrence. They only get heavy usage in wartime or major exercises, generally they spend ~10% of time actually flying, depending on type. This is why you get aircraft like B52 and KC135 operating for 60+ years.

Civil airliners are used much, much more intensively, maybe 70-80% of the time they're actually in the air paying back their capital cost. Engines and airframes need to be able to handle such intense usage.
Click to expand...
Exactly, military aircrafts need a lot more maintenance per flying hours than civilians aircrafts, the same with their engines. You don't want to need the capacity to change engines often and at each destinations....it would be probably the case if they use military engines. Enormous logistic to care for them if they fly each day all over the place. It's why military aircraft are assigned to a base that can maintain them and have tools and parts available.
 
L

latenlazy

Brigadier
test1979 said:
The ws-20 was designed to civilian standards, and its civilian version, the SF-A, was once considered as a domestic engine for the C919. The reason for giving up is that the fuel consumption rate is not as good as the economy problem caused by the CJ1000.
Considering that cj000 will take time, and the possible embargo imposed by the United States, WS-20 is a good transition.
Click to expand...
Airliners won’t fly their C919s if they’re not cost effective. If C919s can’t fly with an engine equivalent in economic performance to western options their sales will either be cancelled or they will be bought and then warehoused. There is no “good transition” for the commercial space. You either perform competitively against the rest of the market or you’re dead.
 
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