In June China revealed that a second squadron had been equipped with its J-20 stealth fighter and that they were satisfied with the performance of the Chinese made WS-10A engines, which replaced Russian AL-31F M2 engines used in J-20 development aircraft. China also revealed that it would soon equip its J-20s with a Chinese made engine that can enable more manoeuvrability with thrust vectoring engines. Currently only the American F-22 has that capability. Russia has engines with thrust vectoring for its most recent non-stealth fighters but has not been able to perfect a more powerful engine with that feature for the stealthy Su-57. If China gets there first with its new WS-15 engine it will definitely be ahead of Russia, but still behind the United States in terms of stealth fighters.
When it comes to fifth-generation (stealthy) fighters Russia was always behind the United States and now is very much in third place behind the United States and China. There is an element of the aspirational even with that third-place status. The U.S. and China already have fifth-generation aircraft in service. Well at least the Americans do and the Chinese J-20 is a lot more operational than the Su-57 by equipping two squadrons using J-20s with less efficient WS-10 engines. WS-10A was successful at replacing AL-31F M2 used for development aircraft. China could have put J-20 into service powered by AL-31F M2, but decided to delay putting J-20 into service until it had a locally made engine available. That happened in 2020 when the first J-20 equipped squadron was announced

One reason for all the optimism over the Su-57 becoming operational is that Russia needs export customers for their stealth aircraft to survive, while the Chinese don’t. Finding Su-57 export customers has been difficult because the Su-57, as described on the spec sheet, won’t be available until the mid-2020s at the earliest. The spec sheet Su-57 is a stealthy, single-seat, twin-engine multirole fifth-generation fighter aircraft developed for air superiority and attack operations. This is the first Russian aircraft in military service to use stealth technology. The Su-57 also has supercruise (going supersonic without the afterburner) capability and advanced avionics capable of dealing with older warplane electronics as well as ground and naval air defence systems. To achieve this performance the current Su-57 requires a more powerful and reliable engine. So far, the AL-41F1 is used in prototype aircraft and that engine it performed as designed, but was not reliable enough for regular use. China claims its equivalent of the AL-41F1, the WS-15 is closer to entering regular service and they are probably right. For several decades China has been playing catch-up with Russian military tech and now China is moving ahead of Russia.

Russia developed the Su-57 as a successor to its Cold War era MiG-29 and Su-27/30 fighters. Stealth was seen as essential but the Su-57 is so expensive, and the Russian Air Force budget so small, and shrinking, that Russia cannot afford many of these stealth fighters. Moreover, it is essential to obtain export sales to make mass production possible at all, not to mention profitable. The recent Russian claim that the manufacturer cut the price 20 percent is also aspirational because a growing number of Russian defence firms are sliding towards bankruptcy. Orders for new equipment have been scaled back since 2014 because of a contracting economy. Russia likes to describe its economic growth as stalled, but the reality is that entire categories of proposed (before 2014) new weapons purchases are being slowly eliminated. Efforts to hide all this, especially the continued decline of the Russian ability to develop and manufacture new weapons, has become less successful as the missed production and “in service” goals increase.

The Su-57 is a prime example of how a system of constantly shifting goals and missed deadlines works. The Su-57 began development in 2002 and the first of ten flyable prototypes flew in 2010. Four non-flying prototypes were also built for ground tests and such. From the beginning, there were problems perfecting the high-performance engines. For example, the first two flight prototypes had to use a less capable variant of the AL-31 engine that was already used by the Su-27 aircraft. The other flyable prototypes used a more powerful AL-41F-1S engine, which was also used in the Su-35, the most advanced (so far) Su-27 variant. Flight testing soon made it clear that even the AL-41F-1S was not powerful enough for the spec sheet Su-57. This meant that the Izdeliye 30 variant of the Al-F41, originally designed for the Su-57, had to be perfected before the Su-57 could enter production as an exportable aircraft. The Izdeliye 30 possessed increased thrust and fuel efficiency as well as 3D thrust vectoring nozzles. At the end of 2017, the tenth flight prototype was equipped with Izdeliye 30 engines and demonstrated its superior performance, including supercruise. However, the Izdeliye 30 was still not reliable enough for sustained use, so mass production of this essential Su-57 engine was delayed. Russia proposed shipping production models of the Su-57 with an Al-F41 variant that enables the aircraft to get the most out of its stealth and high-performance electronics but without the promised supercruise and thrust vectoring manoeuvrability features. Potential customers, including the Russian Air Force, were not interested in purchasing a “developmental aircraft” because that’s what the Su-57 was without the fully functional Izdeliye 30 engines.

China has been copying and improving Russia weapons since the 1990s. The most difficult Russian technology to copy, much less improve on, was high-performance jet engines. The Chinese had more resources than post-1991 Russia and slowly caught up with Russian fighter-engine tech and is now poised to surpass it.

The F-35 was designed to rely on BVR (Beyond Visual Range) weapons and tactics at the expense of traditional close range air combat. BVR tactics are untried in large scale combat, while traditional close range “dogfight” has been around since 1914. Dogfighting isn't quite dead yet and it probably never will be. But more and more, victory goes to the side that can reach out BVR and touch the enemy first with an AMRAAM. The F-35 was optimized for BVR combat because that has been the future of air-to-air warfare for some time now. The Russians and Chinese disagree and the less stealthy Su-57 is now described as a superior dogfighting aircraft with some stealth.

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