Saturday, January 10, 2015

State of Aerospace Engine for PLA

The issue of finding adequate and reliable engine has always been an issue for PLA. The navy seems to be getting by with license building advanced diesel engines, which are not under embargo, for most of its ships and some copied or home developed gas turbines for shipping class that need them. The air force has always seen delays due to problems in local production of engines for a series or waiting for Russian engine options. Shenyang AC has been quite unfortunate in having 2 of its recent aircraft programs (J-8F and J-11B) delayed due to issues with production of a new class domestic engine. I've talked in the past about the state of engine production in China, but was overly optimistic over the program in those cases. So, this entry will attempt to look at some of the domestic engine programs and their import programs.

First, the FWS-10 program is probably the most relevant to the current well being of PLA. We are at a point where all the recent J-11Bs have been produced with FWS-10 along with J-15S and J-16. I'm sure they are still working through problems with a new engine like FWS-10, but it's no longer problematic like early 2011, when SAC had many J-11Bs without engine seating out in its airfields. At that time, the Chinese air force simply refused to take those aircraft because issues with FWS-10. By this point, Russians were more careful about making sure their AL-31F did not end up on J-11B, so the project was basically on hold after that first regiment of J-11B join service with AL-31F. By now, we have seen 4 more J-11B regiments with PLAAF and 3 more J-11B regiments with PLANAF. Assuming that all of these regiments become full at some point this year, that would be approximately 7 x 24 = 168 J-11B/BS in service with FWS-10. Including the J-15/16 prototypes that SAC is building every year, I would guess easily 30 to 40 flankers are produced every year using FWS-10 as power plant. Assuming that a spare is produced for every 2 engines, the yearly production of FWS-10 could be over 100 at this point. So the question is why they are still using AL-31FN on J-10B and AL-31F on J-15. I think at this point they are developing a naval version of FWS-10 to last through the wear and tear of naval operation. At the same time, a higher thrust version is required to support the added take-off weight on J-16. Future flankers will continue to use WS-10 series. A J-10B prototype with FWS-10A is probably still being tested, but it would probably have to match the performance of AL-31FN series 3 (1000 ton more thrust than base layer) in order to be equipped on J-10B production batches. Also, the current J-20 prototypes are also most likely using AL-31FN series 3 engines. As we move forward, this version of AL-31FN is certainly not a viable option for production version of J-20. China can choose a later AL-31FN series that would be equivalent to AL-31FM2 or FM3, which would have comparable or more power than 117S engine that are used on Su-35 right now. If the upgraded variant of FWS-10 goes into production, that could be used in both J-20 or future batches of J-10B. So I would think the first few years of J-20 production (maybe 2 regiments) will be using underpowered engines (140 to 150 kN range with afterburner) and then WS-15 will go into production. Back in 2010, one of the few good Chinese sources on engines mentioned that WS-15 was probably 10 years from mass production based on where the program was at. Articles on WS-15 are hard to come by, but my guess is that they will start to test it out on fighter jet in a couple of years. After that, it will be a waiting game for certification.

The other major question is the status of the WS-13 program. Speculations over this program has been ongoing since JF-17 first went into production. Recently, a second batch of 100 RD-93 was signed with Russia. That would indicate continuing delays in the WS-13 program. At the same time, there was news in the middle of 2014 that Guizhou Liyang was putting significant investment into building a production line for WS-13. We know that RD-93 has been used on FC-31 technology demonstrator and also the Lijian UCAV technology demonstrator, but the vast majority of second batch of RD-93s are still allocated for JF-17. At some point, they will have to test out WS-13 with a batch of production JF-17s. It's possible that a portion of this second order will be used as spares/replacement, but the size of the RD-93 is confusing given the report of WS-13 production line. Going forward, I've talked about how FC-31 does not currently have a viable option for engine. It looks like an improved variant of RD-93, RD-93MA, is under development. When they do choose to move forward with the FC-31 project, I think the current solution of baseline RD-93 (or even WS-13) is too underpowered for even the pre-production batch. So in order to really go forward in FC-31, they have to use RD-93MA before the new 9500 kgf engine under development becomes ready sometimes in the next decade. WS-15 project has higher priority, so that will become ready first.

For the Y-20 project, the early prototypes are all using D-30KP2. D-30 is also used on the 2 regiment of H-6K (about 40 in total) that have recently joined service. A few years ago, it was speculated that a domestic variant of D-30KP2 (WS-18) was getting developed for Y-20 while the more advanced WS-20 engine was still getting ready. China's IL-76 engine testbed has been doing flight testing of WS-20 since 2013. Most recently, they just started doing flight testing of WS-18 on a separate IL-76 testbed. It seems strange rather the older WS-18 begins flight testing over a year after WS-20, but maybe this is aimed for H-6K bombers. Production version of Y-20 is likely to appear sometimes this year or the next, so they will be using the rather old D-30KP2 engine. It doesn't look like PLA is interested in the more advanced PS-90A or even D-30KP3, so Y-20 will be underpowered for a while. At this point, even a D-30KP2 powered Y-20 would be a force multiplier for PLAAF.

Turboshaft engines are not very heavily followed by PLA followers. As late as 10 years ago, issues with producing engine and other subsystems prevented mass production of the domestic helicopters. More recently, helicopter production has been increasing for both PLA and civilian ministries. Since upgraded variant of WZ-6 became available for the Z-8 series, Z-8 production has really taken off for all 3 arms. More recently, Z-18, military version of AC313, using WZ-6C engine is now in mass production for the navy and also the army. We have seen the new Z-18A used in the high altitude of Tibet, which shows how much improvement have been made for WZ-6C. If Huitong's figure of 1300 kw is accurate (and it seems to understated based on other sources), WZ-6C is competitive with PT6B-67A (around 1400 kw) slated for AC313. At the same time, production of Z-10 and Z-19 project have both been going pretty well and look to be sufficiently powered. It seems like production and usage of WZ-9 engine for Z-10 project has been going well. WZ-8 production for Z-9/Z-19 helicopters have been going well too. WZ-16 engine is been developed with France to power Z-15. It may or may not be usable in the future for other Chinese helicopters like Z-10. It seems like they have been able to develop upgraded variants of existing engines either by themselves or with the help of European companies. The only major remaining project that depends on the development of a new engine is Z-20. That is quite a huge improvement for China's engine industry.

Finally, there are some other engines been developed (either new project or copying Russian/Ukrainian engines) for UAVs, missiles and trainer projects. They get much less news, but we do see their appearance sometimes in Zhuhai air show. Very recently, we saw Chengfa finish development on one of those projects. So, this is a rundown on China's engine developments. Similar to 5 years ago, this area remains the achilles heel for the Chinese military industrial complex.


Anonymous said...

Even if Chinese companies can copy and reproduce AL-41, their technological base would still be many years behind world leaders like Rolls-Royce, GE, and Pratt & Whitney. I read somewhere that China's biggest problem is consistent manufacturing of high quality turbine blades, and that problem was apparently solved a year ago. Nevertheless, if engines are still a major problem then they should play their cards right, let the current economic downturn get worse, and then use SNECMA to acquire the right technologies from Rolls Royce.

Qasim said...

Could these RD-93s be used for international sales? It seems like a number of talks did make some fair progress(South America, etc).

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