When the People’s Liberation Army Air Force (PLAAF) acquired its first tranche of Russian-made Sukhoi Su-27SK fighters in the early 1990s, long-time observers of China’s industrial base asked two questions. The first question was how long it would be before the Chinese state-controlled aerospace industry was able to reverse-engineer and build unlicensed copies of the Su-27, as they had done with Russia’s Mikoyan MiG-21 decades earlier.
This was accomplished in slightly more than 10 years, which produced several “indigenous” fighter designs produced at Shenyang that are analogues of the Russian design they were copied from. The Chinese J-11B is a near copy of the Su-27, the J-15 a knockoff of the carrier-capable Su-33 and the J-16 is a duplication of the Su-30MKK models sold to the PLAAF.
The second question was how many years it would be before the Chinese industry started producing some next-generation, original designs by building on what they had learned from the Russians. The next phase—the emergence of “clean-sheet” fighter designs—is well underway now, as seen in the form of the two newest Chinese fighter designs. These are the Shenyang FC/J-31 and the Chengdu J-20.
Cyber Espionage
It’s not uncommon to hear people say that China’s new fighters, the in-service Chengdu J-20 and forthcoming Shenyang FC-31, incorporate stolen design elements from existing American and Russian fighter programs. Russian allegations of copycat technology are primarily based on the overall similarities between the J-20 and Russia’s long-defunct MiG 1.44 program. However, although Russian allegations leave at least some room for debate, the same can’t be said for China’s theft of American stealth fighter designs.
In March 2016, a 51-year-old Chinese national named Su Bin pled guilty to charges associated with what the American Justice Department described as a “years-long conspiracy” conducted in concert with high-ranking members of the Chinese military to steal American military secrets – most notably, the designs for advanced stealth fighters like the F-22 and F-35.
“Su admitted that he conspired with two persons in China from October 2008 to March 2014 to gain unauthorised access to protected computer networks in the United States – including computers belonging to the Boeing Company in Orange County, California – to obtain sensitive military information and to export that information illegally from the United States to China,” reads the Justice Department release.
Su Bin, who worked in Canada under the name Stephen Su, was a well-regarded businessman and entrepreneur in the aviation industry, serving as the sole proprietor of a small company that specialised in aircraft cable harnesses. This company, called Lode-Tech, was described by the Air Force Office of Special Investigations as a “small player” in the field, with only a handful of employees and limited access to broader aviation programs.
However, despite the limited reach of Lode-Tech, Su Bin himself worked tirelessly to establish inroads within the Canadian and American defence industries, forming an extensive network of business contacts that, over time, allowed him to gain increasingly unfettered access to internal networks maintained by various American and Canadian defence contractors.
As Bob Anderson, the FBI’s former head of counterintelligence, put it, “he cultivates you over time.”
Starting that same year, Su began working directly with two professional hackers employed by China’s People’s Liberation Army, using the information he’d gained through his business contacts to enable the theft of more than 630,000 files from Boeing – a massive 65 gigabytes of data – related to the C-17 heavy-lift cargo aircraft. But Su had his sights set on an even bigger prize: information regarding America’s stealth fighter programs.
By 2013, Su had also established connections with GE Aviation in Cincinnati – a firm renowned for its advanced turbofan technologies, which China had struggled to develop for its own stealth fighters. It’s worth noting that Pratt & Whitney powerplants power both the F-22 and F-35, but GE was responsible for competing designs meant for service aboard these jets. According to Defence Department insiders, GE’s YF120 turbofan proposal for the F-22 Raptor was actually the more advanced and capable design. Pratt’s YF119 engine ultimately won out due to its simplicity and the lower risk associated with relying on more mature and proven technologies.
J-20 (Mighty Dragon)
Russian AL-31F engines primarily powered early operational J-20s. China has been transitioning to domestically produced engines, initially the WS-10C as a stopgap, and eventually the more powerful, indigenously designed WS-15 engine, which is intended to provide supercruise capability. The shift away from Russian engines is a key goal for China to achieve full indigenous capability.
The J-20’s overall design is believed to incorporate stolen data and design elements from the U.S. F-22 and F-35 fighters, as well as possibly the Russian MiG-1.44 prototype. This includes design concepts for radar-absorbing materials, engine designs, stealth coatings, and avionics suites.
FC-31 (Gyrfalcon/J-35)
Russian RD-93 turbofan engines powered the early prototypes of the FC-31. Subsequent prototypes have transitioned to the Chinese-developed WS-13 engine, with plans to use the more advanced WS-19 engine eventually.
Chinese turbofan blades are sourced from Russia, France and Germany as China cannot manufacture temperature-sensitive and high-strength titanium alloy blades domestically.
The FC-31 bears a strong visual resemblance to the U.S. F-35 Joint Strike Fighter and is widely believed to have benefited from the same U.S. technology espionage that aided the J-20 program. The design elements, such as the diverterless supersonic inlets and general shaping, show apparent F-35 influence. The avionics systems have also been compared to the F-35’s suite.
China has made significant strides in replacing these foreign components and borrowed designs with domestic equivalents, but the foundational technology acquisition played a substantial role in accelerating its 5th-generation fighter programs.
Foreign components
China’s J-20 and FC-31 fighters have historically relied on Russian-sourced engines; however, the primary “foreign components” are widely considered to be stolen design and technology elements from the U.S. F-22 and F-35 programs, obtained through cyber espionage.
Radar and Armaments
Specifically, to replace the Russian-made NIIP N001 radar with a Chinese-made fire control radar based on the Type 147X/KLJ-X family, the AL-31F engine with WS-10A, and Russian R-77 AAMs with Chinese-made PL-9 and PL-12 AAMs.
The Chinese KLJ-5A is also a copy of the Russian NIIP BAR hybrid PESA radar family, obtained from the Su-35 deal.
The Italian APSIDE missile was reverse-engineered to make the PL-10 missile. The KLJ-7A is a copy of the Russian Zhuk-AME radar, which never passed the bench test.
Composites and alloy materials
China lacks reliable composite and alloy production industries. China relied on dual-use heavy engineering technology imported from Germany, the UK, France and Italy to manufacture J-20 and FC-31. Companies like Siemens, Dassault Aviation and BAE Systems exported composites to the Chinese Comac 919 project, which has been diverted to military projects.
Electro-Optical System
Chinese Electro-optical and Infrared sensors components are sourced from the US, Canada, Sweden and Japan. The Chinese PL-10 and PL-9 missile sensors are sourced from North America, Sweden, and Japan.
Semiconductors
China imports a vast number of semiconductors, with imports totalling $349.4 billion in 2023, making it the world’s largest consumer of chips. The country imports more advanced chips and manufacturing equipment from countries such as Japan and the Netherlands, while also experiencing a surge in domestic production due to US and other export controls.
Most of these semiconductors end up at Chengdu and Shanyang aircraft manufacturing industries.
No matter how China sugarcoats its capabilities, Chinese ballistic missiles, cruise missiles, air-to-air, air-to-ground missiles and fighter jets are full of Taiwanese, American, Japanese and South Korean semiconductors.
The US has imposed export restrictions on China, particularly for advanced chips used in AI and military applications. These controls are a significant factor in China’s efforts to secure its supply chain.
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