Procurement: Engine Perfection Marathon

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November 25, 2018: China recently showed off one of its J-10B fighters equipped with a locally made WS-10 engine featuring, for the first time, thrust vectoring. This WS-10 engine was a development prototype and had apparently been flying for a while because the J-10B pilots demonstrated skill and experience in getting the most out of what was a very basic vector capability (the engine could only deflect exhaust downward for a few degrees). The most effective thrust vectoring nozzles can deflect exhaust up and down as well as sideways and to a greater degree than the WS-10 prototype demonstrated. For those who follow Chinese technology development, what was recently demonstrated is solid progress and indicates that China is on its way to achieving the more complex thrust vectoring it needs to match what Russian and Western jet engines can handle.

China has been seeking to master and implement thrust vectoring for a long time. While China can steal the technical specs for thrust vectoring on Russian and Western aircraft, manufacturing it is another matter and requires training engineers and workers for the task as well as figuring out all the crucial design and manufacturing details that are not written down. This takes a long time. China has shown a willingness to take whatever time it takes to master manufacturing methods for gear that only a few nations can produce.

China has long sought to eliminate its dependence on foreign suppliers (especially Russia) for high-performance jet engines. The biggest problems have been with the WS-10 series, which was designed and produced in China and the government has been pressuring the aircraft manufacturers to use Chinese made engines like this instead of Russian imports. This has not been working out as the government wants. For example, the Chinese carrier fighter, the J-15, is supposed to have a more powerful Chinese made engine so that it can carry more weight using the ski jump deck on the first two new Chinese carriers. One disadvantage of the ski jump deck is that it cannot launch aircraft as heavy as a catapult can. China developed a more powerful version of their WS-10 engine (the WS-10H) for the J-15 but has only been seen in a few J-15s. Until recently J-15s were still using Russian AL-31Fs but apparently more are receiving WS-10s, but apparently not the more powerful H version. China keeps most details of its WS-10 development secret, but they cannot hide which of their aircraft are using the WS-10 and which the Russian made AL-31s that the WS-10 is based on and is supposed to replace. It is obvious that WS-10s have been slow to show up and that indicates the quality control and reliability problems of the WS-10 persist despite government denials. That may have been one reason the WS-10 with working thrust vectoring was publicly demonstrated.

The Chinese have built nearly 300 WS-10s for J-11 (which the J-15 is based on) type aircraft and found the engines reliable enough to keep using. The WS-10 is still a work in progress but it is still less reliable than the Russian ones and China is willing to undergo the hassle of maintaining and replacing the WS-10s more frequently as they learn how to design and build sturdier engines of this type. The first WS-10s began showing up in J-11s back in 2004. In 2010 China revealed that it was replacing the Russian engines in its J-10 fighter, installing Chinese made WS-10A in place of the Russian made AL-31FN. Shortly after that announcement China ordered another 123 AL-31FNs, to be delivered by 2012. More AL-31s have been ordered but at the same time, more Chinese fighters were being seen with WS-10s. Despite that, the demand for AL-31s, based on the number of modern jet fighters China wants to build, is exceeding the Russian engine building capacity.

The Chinese claim the WS-10A is superior to the AL-31F, even though the WS-10A copied a lot of the Russian technology. The Chinese say they have improved on that. For example, as delivered from Russia, the original AL-31 was good for 900 hours of operation. The Chinese claim their engineers figured out how to tweak the design of the engine so that it would last for 1,500 hours. Russia has since improved their basic AL-31 lifetime to 1,500 hours, and, most recently, 2,000 hours. When pressed, the Chinese claim that they simply cannot produce enough WS-10As for all the new airframes they are building. But the reality is that the WS-10As have some serious, unpredictable and persistent reliability problems that limit the number of reliable (enough for regular use) engines available.

Back in 2011, China believed it would be free from dependence on Russia for military jet engines by 2016, which implied that Chinese engine manufacturers still had a way to go. Now the most the Chinese will admit to is that there will be no need for Russian engines by the end of the decade, maybe. Meanwhile, China continues to import AL-31s and the RD-93 (a version of the MiG-29's RD-33) for the JF-17 (an F-16 type aircraft developed in cooperation with Pakistan) from Russia. These engines are expensive, with the RD-33 going for about $3 million each and the AL-31 for about a third more.

Since the 1990s Chinese engineers have managed to master the manufacturing techniques needed to make a Chinese copy of the Russian AL-31 engine. This is part of a program that has also developed the WS-13, to replace the RD-93 as well. While the Chinese have been able to build engines that are durable, they are still having problems with reliability. Apparently, it is still worth buying more Russian engines because the Chinese models are out of action too often, which keeps the jets grounded for repairs or, worst of all, an engine change.

China has long copied foreign technology, not always successfully. But since the 1990s China has poured much money into developing a jet engine manufacturing capability. The Chinese encountered many of the same problems the Russians did in the beginning. Developing the necessary engine design and construction skills is difficult. But China has several advantages. First, they knew of the mistakes the Russians had made, and so were able to avoid many of them. Then there was the fact that China had better access to Western manufacturing technology (both legally and illegally). Finally, China was, unlike the Soviets, able to develop their engine manufacturing capabilities in a market economy. This was much more efficient than the command economy that the Soviets were saddled with for seven decades. The Chinese consider all this part of the learning process and they do learn from their mistakes. Despite all that, every year more Chinese fighters are seen with the WS-10 and there does not appear to be any sharp increase in accidents (because of engine problems). China perseveres.

The WS-10 is not the only Chinese jet engine that is proving difficult to perfect. For example, there are several problems with the J-20 stealth fighter but the main ones have to do with stealth (the delicate materials on the airframe that make radar detection less effective) and engines. The most obvious problem is the engines. The WS-10s currently installed are a stopgap and not efficient enough to support supercruise (go supersonic without using the afterburner and becoming easier to spot). China has had persistent problems developing high-performance jet engines. China has been developing the more powerful (and supercruise ready) WS-15 engine since the 1990s for a larger aircraft like the J-20 but has not been able to get the engine to work. Officials also confirmed rumors that a WS-15 exploded during a 2015 static (on the ground) test. That failure had been a secret but when an engine this big fails by blowing up the incident is difficult to hide.

No date was given as to when the WS-15 would be available for use or whether it would have the same thrust vectoring capabilities the F-22 uses. At first, a more powerful and reliable version of the WS-15 for J20 was believed possible by 2020 but changes in the shape and weight of the WS-15 would require modifications to the shape of the J-20 and that would require a lot of testing to ensure that stealth was not compromised. The factory would have to install new or modified manufacturing equipment and suppliers would have to do the same to produce the new airframe components. Meanwhile, the WS-15 reliability problems are still not completely resolved. Another potential J-20 problem is its ability to operate effectively in a wide variety of climates. For example, development and pre-production J-20s were flown frequently in a wide variety of climates during 2017 and that may have revealed unanticipated problems requiring fixes that are still in the works.

Another reason for showing off the thrust vectoring WS-10 in the J10 is because China is again trying to obtain some export sales for its J10 jet fighter. This comes after China finally got the latest version of the J10 fighter, the J10C, into service in mid-2017, 13 years after the first J10s entered service in 2004. This in itself was after a long (since 1988) effort to get an original modern Chinese fighter design operational.

The latest version uses more composites in the airframe and has improved electronics. It is the most widely used modern Chinese jet fighter (with nearly 400 in service). More numerous are several different models of modern Russian jets. Legal and illegal copies of the Russian Su-27 were obtained by the end of the 1990s but China produced a lot of J10s because, well, they were a Chinese, not Russian, design. That meant it took longer to get the J10 into service and China has used the J10 to advertise its new aircraft development. This includes electronics, like a “glass cockpit”, helmets with built-in HUD (head-up display) and “look and shoot” capabilities. J10s got the first Chinese fire control systems that handled smart bombs (satellite or laser guided)/ The J10 was the first to receive targeting pods, ECM pods and improved fly-by-wire systems. The J10 was the first Chinese jet fighter to switch to Chinese made engines rather than ones bought from Russia. Despite all this, China has not been able to get any export action.

 


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