Chinese Engine Development


free_6ix9ine

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The ZF850 turbojet from Jiangxi Zhongfa Tianxin Engine Technology Ltd. It will soon be used on the Cloud Shadow UCAV. Two pre-production samples have already been delivered, with four more to be delivered by year end 2020. Serial production will commence in 2021. The company is currently exhibiting the engine at the ongoing Nanchang Aviation Conference/Show.



Turbojet? Seems strange for a subsonic drone.
 

free_6ix9ine

Junior Member
Registered Member
The ZF850 turbojet from Jiangxi Zhongfa Tianxin Engine Technology Ltd. It will soon be used on the Cloud Shadow UCAV. Two pre-production samples have already been delivered, with four more to be delivered by year end 2020. Serial production will commence in 2021. The company is currently exhibiting the engine at the ongoing Nanchang Aviation Conference/Show.



Looks similar to similar to the firebee engine. Yikes. I can't believe China is still copying an old turbojet from the 60s. Why not make improvements, ie add a power turbine and fan....

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free_6ix9ine

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Has China ever attempted to convert the design of the old WP-7 turbo jets used in the J-7/mig 21s into a more modern turbofan by adding a power turbine stage connected to a bypass fan? This would be much more efficient and would create a nice little 30kn turbofan for applications like heavy UCAVs, trainer jets, small business jets that can be converted into military use, etc.

Currently China has one or maybe two turbofans in service? The WS-10 and the WS-9? The WS-10 is too big for most UAV applications, the WS-9 i heard wasnt a big success either due to quality control reasons. All Upcoming turbofans like the WS-15 or WS-20 are far too powerful for UAVs.

So a WP-7 based low bypass turbofan would fit a nice niche that could be used on large UAVs, in the same class as the global hawk, GJ-11.
 

latenlazy

Colonel
Has China ever attempted to convert the design of the old WP-7 turbo jets used in the J-7/mig 21s into a more modern turbofan by adding a power turbine stage connected to a bypass fan? This would be much more efficient and would create a nice little 30kn turbofan for applications like heavy UCAVs, trainer jets, small business jets that can be converted into military use, etc.

Currently China has one or maybe two turbofans in service? The WS-10 and the WS-9? The WS-10 is too big for most UAV applications, the WS-9 i heard wasnt a big success either due to quality control reasons. All Upcoming turbofans like the WS-15 or WS-20 are far too powerful for UAVs.

So a WP-7 based low bypass turbofan would fit a nice niche that could be used on large UAVs, in the same class as the global hawk, GJ-11.
This is not a good way to develop engines. And also China already has light turbofan designs.
 

free_6ix9ine

Junior Member
Registered Member
This is not a good way to develop engines.

I disagree. Engine tech is essentially an iterrative process. The AL 41 came from the AL 31 which was a turbofan adaptation of the AL 21 by the addition of a power turbine and bypass fan. The F100 has its roots in the J79 turbojet which also served as the gas generator aka "core" of the CF-6 high bypass turbofan which powered the C-5 galaxy.
 

latenlazy

Colonel
I disagree. Engine tech is essentially an iterrative process. The AL 41 came from the AL 31 which was a turbofan adaptation of the AL 21 by the addition of a power turbine and bypass fan. The F100 has its roots in the J79 turbojet which also served as the gas generator aka "core" of the CF-6 high bypass turbofan which powered the C-5 galaxy.
It may be iterative, but you can’t simply slap a fan section onto an old turbojet core that was never developed to be a turbofan. The whole engine works as one integrated component. Treating components as modular when they’re not designed as such is one reason why the WS-10’s development process was such a nightmare. Mix and match isn’t a good way to do jet engine design when your downstream mechanisms have high dependency on your upstream mechanisms, unless you explicitly design such components with such flexibility in mind first.
 

free_6ix9ine

Junior Member
Registered Member
It may be iterative, but you can’t simply slap a fan section onto an old turbojet core that was never developed to be a turbofan. The whole engine works as one integrated component. Treating components as modular when they’re not designed as such is one reason why the WS-10’s development process was such a nightmare. Mix and match isn’t a good way to do jet engine design when your downstream mechanisms have high dependency on your upstream mechanisms, unless you explicitly design such components with such flexibility in mind first.

A turbo jet is essentially the "core", if by core you mean the thing that generates hot gasses. By adding another turbine that is only linked to a fan, your essentially just converting that heat energy into rotational energy.
 

latenlazy

Colonel
A turbo jet is essential the "core", if by core you mean the thing that generates hot gasses. By adding another turbine that is only linked to a fan, your essentially just converting that heat energy into rotational energy.
Yes, but that does not mean an engine designed to be a turbojet would take well to conversion into a turbofan. You make it sound like gas is just homogenous ether. The way your fan section impacts the gas dynamics downstream into your core is a very serious design detail that you’re glossing over.
 

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