It seems that stating that "we know nothing" is the most accurate statement when talking about the WS-15. It seems that no one knows for certain, how along it is in development, if it has been tested inflight. It could even be in "development hell". The fact that J-20 is now flying with WS-10 doesnt help to dispel that idea.
Chinese Engine Development
- Thread starter jackbh
- Start date
The "we know nothing" in my original post has a context which was against the "over speculation". In fact we do know something about WS-15. There has been report of "engine casing production plan (years) for XX-15 in the number of low two digits" which certainly was about WS-15 that is in late development, not "hell" at all. J-20 using WS-10 says nothing certain of WS-15 either, because we do not know if this was anticipated and planed at the beginning of J-20 program. If it was known by the program that WS-15 won't be ready by 2020, then there is nothing wrong in WS-15's progress. And nobody has ever said about WS-15 being ready in 2020, but rather rumor says 2025.
So to conclude, my "we know nothing" should be precisely stated as "do not easily conclude anything around WS-15". This applies to both sides of overly positive and negative. I hope this time, I got my statement water-tight.
Once developed and tested, you could simply swap them out and leave it at that, this would give you a small weight saving with little impact on other parts of the engine. Conventionally, it would be more beneficial to take advantage of the opportunity to increase fan size and go for a higher bypass ratio, though. As gelgoog says, that involves revising the entire low pressure spool including shaft and low pressure turbine as well as the nacelle to accommodate the larger diameter.
To illustrate, the Russians have mounted drop-in replacement composite blades on the PD-14 as a test for later use on the PD-35 widebody engine and the expected weight saving is only 20-30kg. This is for an engine weighing ~3t with a BPR of 8.5 (a reduction of just 1%), but on the ~8t PD-35 with a BPR of ~11 it is estimated to save around 400kg (5%!!!) over a PD-14-style hollow titanium fan! So there is a strong incentive to increase bypass ratio for lower SFC with composite materials, even to the point of accepting a net increase in engine weight.
With the CJ-1000A however, the original engine basically has the BPR increase already built in (which is precisely why I think it will turn out overweight). So in this specific example we'd be talking about a simple drop-in, with a much larger than usual weight benefit (at a guess far in excess of 100kg, if you also include a composite fan case). At the aircraft level (with two engines), that's at least 3 additional fare-paying passengers' worth at no range penalty.
What if they built in the BPR increases because they’re already looking at more weight saving components and materials?
That is quite likely the rationale, but if they don't mount composite fan blades on an actual CJ-1000A soon, chances are it will have to be introduced on an improved variant after service entry with metal blades. The very fact that ACAE took the time to develop hollow titanium blade technology also indicates a composite fan was not considered mature enough to meet the desired schedule. Otherwise they'd have simply mounted conventional solid blades on the non-flying demonstrators and skipped straight to a CFRP solution at a later stage and for production (as is obviously being done with the TiAl LPT).
Last edited:
Not the first time we’ve seen staggered development and component creep in Chinese tech projects that are trying to catch the technological leading. I guess there are potential issues with project management that this can introduce for a commercial project but they also have much greater control over their own domestic market and regulatory environment so...
Is that all we know??? thats something...next to nothing. What about any rumours or information that it has been test-flighted?
Or perhabs can be stated as "do not conclude anything around WS-15".
1. If they had laid out a 5(?) year low volume production plan of engine casing, how likely do you think that they have not flight test the "prototype"?
2. Let's not go into a word of play. Be moderate and cautious is all that is needed, no need to jump from overly confident of something to the other extreme side of nothing and anything.
Hendrik_2000
Brigadier
Like they say Rome is not built in the day. Expecting China to be on the same level as the west when it come to Jet engine is just plain ridiculous and delusional. Forgetting that 20 years ago air travel in China does not exist. Just getting by with food and keep the body warm is a struggle let alone travelling by Air.
Air travel and civilian jet engine self sufficiently is a luxury that can wait. For the masses China can get by using HSR to travel inside the country and she is independent when it come to designing, producing, constructing world class HSR.
But China is now independent when it come to military jet engine production that is something more important and worthy of celebration!
In what universe China was like that 20 years ago?