Throttle up: China closes the jet engine gap

The Chinese defense industrial base is infamous for its tendency to “borrow” from foreign designs, particularly in the aerospace industry.

Almost the entirety of China’s modern fighter fleet have either borrowed liberally from or directly copied foreign models.

The J-10 was reputedly based on the Israeli IAI Lavi and by extension the United States’ General Dynamics F-16; the J-11 is a clone of the Russian Su-27; the JF-17 is a modern development of the Soviet MiG-21; the J-20 bears an uncanny resemblance to the F-22, and finally, the J-31 is widely believed to rely heavily on technology appropriated from the F-35.

According to a special report by Robert Farley and J. Tyler Lovell in The National Interest, appropriation saves China time and money on research and development, allowing it to modernize the PLAAF at a fraction of the cost of its competitors. However, the appropriation strategy remains constrained by bottleneck technologies due to lack of testing data and industrial ecology.

This problem is starkly illustrated by China’s ongoing difficulty in producing a high-quality indigenous jet engine, the report said.

Even today, jet engines remain an obstacle for PLAAF fighter modernization, with its early 5th generation prototypes notably underpowered. Further complicating the problem, Russia is wary of supplying engines more powerful than the AL-31 used to power its Su-27s. However, China has several avenues to work around this.

The most obvious option is simply to build a better indigenous engine.

In 2016, China’s 13th Five-year Plan for the National Development of Strategic Emerging Industries emphasized the importance of improving the performance of indigenous jet-engine designs and the further development of the aerospace industry, the report said.

It appears that there has been at least some success, as the latest J-20 prototypes are powered by upgraded WS-10 engines that are supposedly stealthier and more powerful than the AL-31. However, the lack of public information regarding China’s indigenous engine programs makes their true quality difficult to ascertain, the report said.

Early models of the WS-10 used to power Chinese Flankers proved dramatically inferior to the AL-31. While the privately owned Chengdu Aerospace Superalloy Technology Company (CASTC) has recently made great advances in turbofan technology, allowing for hotter, more efficient engines, the fruits of its breakthrough have yet to reach frontline PLAAF units, the report said.

A simpler method is to buy foreign fighters that have advanced engines, as was the case with the PLAAF’s purchase of Su-35s from Russia, the report said. The Su-35’s AL-41F1S, alternatively known as the ALS-117S, is an exceptionally powerful thrust-vectoring engine which represents a quantum leap over the AL-31.

While China originally expressed interest in the ALS-117 as a stand-alone product, Russia’s refusal to export the engine alone necessitated the purchase of the Su-35. Russia insists that extensive IP protections safeguard the ALS-117 from Chinese reverse engineering.

Russian sources claim it is nearly impossible to reach the “heart” of the engine without breaking it. Furthermore, China’s previous difficulties with the WS-10, despite ready access to the AL-31, show that access to foreign engine designs does not immediately translate into the ability to produce engines of similar quality, the report said.

Furthermore, disrespecting Russian IP protections it had agreed to honor might restrict China’s access to advanced Russian systems in the future. Finally, if the Russians are correct that it is effectively impossible to access the ALS-117’s core without breaking it completely, attempts at reverse-engineering it would rob the PLAAF of advanced combat aircraft that would quite obviously be useless without engines, the report said.

Thus, while the PRC may derive short-term advantage from reverse engineering the ALS-117, it risks killing the goose that laid the golden egg. However, the grim prognosis for the future of the Russian arms industry may force it to look the other way, as losing access to the Chinese market would be a body blow.

Finally, China could use its bourgeoning civilian jet industry as a springboard from which to derive military applications. A focus on civilian aviation opens up greater opportunities for cooperation with Western firms while opening up new export markets for Chinese aviation technology, the report said.

For example, Germany is interested in purchasing Chinese turbine blades, which are said to be superior to German designs in many ways (ironically, much of this expertise comes from China gobbling up German companies.)

Despite the formidable obstacles we’ve touched on, Chinese advancement in military aviation continues apace, and it is unlikely that China will lag behind in engine technology forever.