Summary and Key Points: China’s 2015 purchase of 24 Russian Su-35 fighter jets sparked concerns about reverse-engineering, mirroring China’s earlier replication of Russia’s Su-27.
-The Su-35, a highly advanced 4th-gen “plus” fighter, can supercruise at Mach 2.35 and offers significant technological advantages such as thrust-vectoring engines, enhanced avionics, and reduced radar cross-section.
-Observers suspect China aimed to assimilate technologies like the Su-35’s powerful AL-117S engines, advanced Irbis-E radar, and electronic warfare systems into domestic platforms like the J-20.
-This acquisition aligns with China’s strategy of absorbing foreign technology to rapidly modernize its military capabilities, potentially threatening Russia’s technological edge and reshaping Indo-Pacific aerial combat dynamics.
Did China Buy Russia’s Su-35 Jets Just to Copy Their Technology?
China acquired 24 Su-35s from Russia, sparking speculation that Beijing aimed to reverse-engineer advanced Russian technologies, as it previously did with the Su-27-derived J-11.
Russia’s Su-35 is an upgraded variant of the high-speed Su-27, and it has been integrated with an additional suite of upgrades intended to rival 5th-generation aircraft as a 4th-gen “plus” aircraft.
The Su-35 can hit Mach 2.35 speeds and operates with a “supercruise” capability similar to an F-22, meaning it can sustain Mach speeds without needing an afterburner.
All of this make these fighter jets highly desirable, and why an emerging superpower wanted to buy them, with possibly some evil intentions.
Why China Wanted the Su-35 Fighter: All About the Tech?
These attributes may have contributed to a Chinese decision to buy 24 Su-35s from Russia in 2015 in a $2.5 billion deal, a development spelled out in a 2018 essay in the Diplomat.
Following the initial agreement, Russian Su-35s arrived in successive waves over subsequent years, and many speculated that, indeed, China would seek to re-engineer Su-35 technologies for use in its own, domestically-built fighter jets.
China became the first international customer for its Su-35 fighter jets in November 2015.
However, China may not have had an actual interest in “flying” its acquired Su-35s but may have simply borrowed or “stolen” the technology for its growing air fleet.
Acquiring and then stealing more foreign technologies is consistent with China’s widely observed modernization tactics.
Yet, it may not be apparent if engineering details learned from acquiring Su-35 can be reverse-engineered and replicated for Chinese fighters.
A significant essay in this publication last month refers to China’s well-known and heavily documented efforts to copy or steal foreign technologies, and it may not surprise anyone to observe that China’s J-11 4th-generation fighter emerged shortly after China had acquired the Russian Su-27.
This may not be a coincidence, as the essay noted above explains, as acquiring Su-35s could simply be a more modern variation of this kind of technology.
Stealing Russian Technologies?
What kinds of Su-35 technologies might China be interested in?
The PRC has a history of domestically engineering its versions of advanced foreign technologies; in recent years, the PLA Air Force built its own indigenous WS-15 engine for its J-20 to replace previous Russian engines.
It would, therefore, make sense that perhaps China simply wanted to “study” and learn about Russian avionics and fighter jet technologies.
Why China Could Want to Steal Tech from the Su-35
For instance, an engaging and potentially lesser-recognized factor is that the Su-35, while not an entirely stealth aircraft, does appear to have some radar-cross-section reducing attributes.
The Su-35 looks stealthy to the observer’s eye, as it has a slightly more rounded fuselage than most more sharply-edged 4th-generation aircraft.
A blended wing-body presents fewer sharp contours and angles likely to generate a return rendering to enemy radar when electromagnetic “pings” bounce off the aircraft.
Looking closely at the fuselage, the Su-35 does seem to resemble the F-22 slightly, yet that by no means indicates its stealth properties are comparable.
The Timing and What China Was After
The Su-35 did, however, arrive as recently as 2014, a timeframe suggesting that the aircraft may incorporate many more cutting-edge upgrades in weaponry, sensing, avionics, mission systems, and non-kinetic weapons, such as EW.
Some newer technologies might contribute to the Su-35s high 1.30 thrust-to-weight ratio.
An interesting essay in The Diplomat from back in 2019 further elaborates on some of the advanced technologies woven into the Su-35.
“The Su-35 is an upgraded fourth generation, twin-engine, multirole air superiority fighter aircraft powered by two AL-117S turbofan engines and fitted with thrust vectoring nozzles allowing the aircraft to attain “super maneuverability”. Additionally, the aircraft features “an export-standard radar system — the Irbis-E passive-electronically scanned-array radar, capable of tracking up to 30 targets simultaneously and purportedly able to engage up to eight — an electronic warfare and communications suite, as well as a newly integrated receiver for the domestically-built BeiDou satellite navigation system,” the essay says.
Could this be what the Chinese were after? Time will tell.
About the Author: Kris Osborn
Kris Osborn is the Military Technology Editor of 19FortyFive and President of Warrior Maven – Center for Military Modernization. Osborn previously served at the Pentagon as a highly qualified expert in the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters Degree in Comparative Literature from Columbia University.
Pat
March 10, 2025 at 3:52 am
China paid Russia for the fighters, and Russia was willing to sell them. This isn’t stealing, it is called bilateral trade. You are biased to the point that your article isn’t worth reading. I wasted my time. By the ways, country spys on each other, I am sure America are desperately trying to steal hypersonic technologies from China and Russia.
Fred Bloggs
March 10, 2025 at 9:19 am
Completely agree with the previous comment. A pathetic, biased one-sided polemic not worthy of being published. Claiming the Chinese have stolen the aircraft and giving the impression that they have evil intentions misses the most basic point of state security – namely a state’s responsibility towards its own national interests. Thinking that it is only a rogue state such as the US that is entitled to national interests is just so laughable.
Godfree Roberts
March 11, 2025 at 2:12 am
China’s well-known and heavily documented efforts to copy or steal foreign technologies???
Not a single case of significant IP theft proven in any IP court on earth. China doesn’t need to steal. Honestly.
VBR
March 11, 2025 at 6:11 pm
China made a very small order. Russia expected a much larger one. Russia itself was suspicious that such a small order was intended only to get hold of the jet to inspect its most interesting features. This is totally believable. China has been rapidly developing its own domestic aircraft over the last couple of decades. It made total sense to reverse engineer the best bits of Russian export models. Ten years later China has clearly surpassed Russian technology in this field and will continue to accelerate ahead. Russia is now firmly a junior partner without doubt. It needs China A LOT more than China needs Russia. The world changed a lot in these last ten years.
USA,USB,USC
March 11, 2025 at 10:52 pm
So USA has nothing to be “stolen” anymore? Changed to Russia?
Another question is where did China steal hypersonic engine, 6gen fighter jets, balitic missile can hit moving ships and etc. Etc.?
The author is too stupid to answer.