Why China's Air Force Still Struggles to Build Jet Engines

September 18, 2021 Topic: Chinese Military Region: China Blog Brand: The Reboot Tags: Jet EngineIntellectual PropertyJ-20Su-35Arms Sales

Why China's Air Force Still Struggles to Build Jet Engines

A lack of human capital and trade secrets complicates jet engine development, but China won't lag behind forever.


Here's What You Need to Know: It is unlikely that China will lag behind in engine technology forever. Advances in 3D printing may yet provide a way for it to rapidly build, prototype, and develop jet engines.

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 Joint Strike Fighter. 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 problem of technology mismatch, at its root, is that the thief lacks trade secrets and human capital associated with the manufacturing and assembly of a system. At the very least, this absence can make the replication of foreign systems a costly and time-consuming process, as the thief needs to develop manufacturing procedures from scratch.  At worst, it can lead to seriously substandard components that reduce the capabilities and reliability of a system. Chinese efforts to reverse engineer certain Russian jet engines during the 1990s and 2000s invariably produced engines with extremely short lifespans, and without the power of their Russian counterparts. 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. 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. 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.

If the private sector proves key to breaking through various technological bottlenecks in elements of aerospace design, then political ramifications may follow. Presently, state-owned aviation manufacturers are politically ascendant, with some state-owned enterprise leaders even granted governorships. If privately owned firms like CASTC produce superior results, they may rise in political influence, the more established and politically connected state firms could consume them, or they could form comprehensive public-private partnerships with state-owned firms while retaining a degree of autonomy. Whatever the case, the implications could be profound for the Chinese defense industrial base and national innovation system.

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 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. However, given China’s questionable record of respecting intellectual property, it is plausible that they will attempt to reverse-engineer parts of the ALS-117 anyway, although this is harder than it sounds. 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. 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. 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. Russia’s leverage is also shrinking; as China’s technological and industrial base improves, the importance of Russian imports continues to decrease. Beijing may feel confident enough in the disparate power differential to call Moscow’s bluff. Yet doing so risks derailing the positive relationship in which the two countries have invested considerable diplomatic capital.

Finally, China could use its bourgeoning civilian jet industry as a springboard from which to derive military applications. This certainly has its advantages. A focus on civilian aviation opens up greater opportunities for cooperation with Western firms while opening up new export markets for Chinese aviation technology. 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). Additionally, it meets a domestic need, as China is the world’s largest market for civilian aircraft. However, American and European companies operate under severe restrictions regarding technology transfer, undercutting their ability to provide useful information. Additionally, political pressure or IP theft could scare away Western aerospace firms just as they are starting to invest in Chinese production. With intellectual property theft already a key point of contention, this could further exacerbate declining Sino-American relations and add fuel to the fire of a trade war. The result could damage the very industrial base China is trying to expand and modernize.

Despite these formidable obstacles, Chinese advancement in military aviation continues apace, and it is unlikely that China will lag behind in engine technology forever. Advances in 3D printing may yet provide a way for it to rapidly build, prototype, and develop jet engines. However, while 3D printing is already used by militaries worldwide to produce parts for aircraft and ships, it has yet to produce a modern military-grade turbofan jet engine. Given the inherent complexity of such a task, it will likely take several years for such technology to mature enough for widespread implementation. For now, it appears that the PRC must make difficult choices if it is to master fighter engine design, and thus maximize the effectiveness of its air arm.

J. Tyler Lovell is a graduate of the University of Kentucky's Patterson School of Diplomacy and aspiring PhD student. He has been previously published in the popular defense website Foxtrot Alpha and the foreign policy blog Fellow Travelers.

Robert Farley, a frequent contributor to TNI, is a Visiting Professor at the United States Army War College. The views expressed are those of the author and do not necessarily reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government.

This article first appeared in 2018.

Image: Reuters.