The Truth about the WS-10

Written by Ryan Crierie on Friday, January 7, 2011 at 5:22 pm

I’ve been reading up on the WS-10 lately with all the news in the media about the new Chinese J-14/J-20 Stealth fighter prototype.

One of the most common refrains by the ‘learned’ who say that we don’t need to worry about the J-20 is that “China cannot make engines”.

To support this, they usually trot out Russian sources who tell us that the WS-10 is a copy of the AL-31F, and that the Chinese can’t make a working copy of it; so thus, they are dependent on Russian Arms Exports for their superfighter(s).

The problem is, it’s not true.

The basic WS-10 technology dates to 1980 when China initated development of high performance engines to support next generation aircraft.

To support this in 1982 they bought two CFM-56 turbofans from the US. There was quite some concern over this at the time because the CFM-56 core is a derivative of the F101 core that powers the B-1, and the F101 was also worked up into the F110 core which powers some F-16s.

In 1986 with the technology in hand, Deng Xiaoping initaled the plan for turbofan development. By 1989 actual development and manufacture of the WS-10 core began and it achieved first power in December 1992.

Of course, they had problems through the 1990s with the turbine and compressor blades so flight testing didn’t begin until 2001/02. And of course there were problems which bedeviled it due to poor quality control, like a WS-10 exploding after takeoff in a test mule Su-27 in 2004.

The WS-10A finally passed it’s 40 day endurance test with no failures in November 2005.

Some Specifications:

0.78:1 bypass ratio
Compressor: 3 Fan and 9 Compressor Stages
Turbine: 1 High Pressure and 2 Low Pressure Stages
Diameter: 950mm inlet
Weight: 1,494 kg

0.571:1 Bypass Ratio
Compressor: 4 Fan and 9 Compressor Stages
Turbine: 2 single stage turbines
Diameter: 910mm inlet, 1,240mm external
Length: 4,950mm
Weight: 1,530 kg

As you can see, the WS-10 has a totally different internal layout, higher bypass ratio, and larger inlet than the AL-31F. So it is in no way a clone of the AL-31F.

So what does the WS-10 come close to resembling? Why yes, none other than the F110 with it’s 0.85:1 bypass ratio and the SAME exact compressor and turbine arrangement!

No wonder the WS-10 has suffered a very long protracted development and suffers from slow throttle response — the Chinese had to not only reverse engineer the CFM-56 turbofan core, but then re-militarize it back into a F110 clone.

That’s up there with the Japanese reverse engineering the Jumo 004B from a grainy photograph.

Oh, since they now have a working CFM-56 derivative core in production, making large, high bypass ratio turbofans for the Y-20 strategic airlifter is a lot easier.

Categories: Aircraft

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