Russia's Su-57 5th-Gen Fighter Jet Shows Noticeable Design and Functionality Inheritance from Su-30MKI

Russia's Sukhoi Su-57 "Felon," the nation's premier fifth-generation stealth fighter, displays a clear design and functional lineage from the earlier Su-30MKI "Flanker," a 4.5-generation multirole aircraft developed in collaboration with India.

This connection highlights both the evolution of Russian aerospace engineering and some persistent design philosophies.

The Su-57's visual similarity to the Su-30MKI is immediately apparent. Both jets employ a canard-delta wing configuration, a design feature originating from the Su-27's emphasis on maneuverability. While the Su-57's canards are smaller and better integrated into its overall stealth design, the shared heritage is undeniable.

Another shared feature is thrust-vectoring nozzles, which allow for exceptional maneuverability at low speeds and high angles of attack. This capability, long favored by Russian aircraft designers, offers advantages in close-range combat, although it's a characteristic less prioritized in Western stealth fighter designs like the American F-22 Raptor, which focus more heavily on minimizing radar signature.

The Su-57 also adapts the Su-30MKI's wider fuselage and splayed engine nacelles configuration, modified to accommodate internal weapons bays and achieve a lower radar cross-section (RCS). The Su-57 is estimated to possess RCS between 0.1 and 1 square meter, a significant improvement of Su-30MKI's 20 m².

However, this design inheritance raises questions about the Su-57's true "fifth-generation" status. The Su-30MKI, developed in the 1990s, was itself an advancement of the 1970s-era Su-27 platform. The Su-57's adherence to a similar design template suggests a more evolutionary, rather than revolutionary, approach.

The Su-57's stealth capabilities are reportedly hampered by several factors, including exposed engine blades, protruding sensors, and the use of riveted panels. These features are typically absent in other fifth-generation fighters like the American F-35 Lightning II and F-22 Raptor, which are designed to reduce radar cross-sections to under 0.001 square meters.

The broader context reveals a consistent pattern in Russian fighter jet development. The Su-27, which first flew in 1977, became the foundation for a series of subsequent aircraft, including the Su-30, Su-35, and Su-37. Each of these models built upon the Su-27's core strengths: agility, long-range capabilities, and a large payload capacity.

The Su-30MKI, produced by Irkut Corporation under the Sukhoi umbrella, is a prime example of this iterative approach, integrating Russian airframe designs with avionics and systems from France, Israel, and India. The Su-35, a further modernized 4.5-generation variant, incorporated advanced avionics and the Irbis-E radar system, but maintained the familiar "Flanker" silhouette.

The Su-57, initially conceived as part of the PAK FA (Future Air Complex for Tactical Aviation) program in 2002 to challenge the F-22, continues this trend. Its development has been plagued by funding issues and technical challenges. As of early 2024, reports indicate that only a limited number of serial production Su-57s have been delivered to the Russian Aerospace Forces, significantly fewer than originally planned.

Production has also been affected by international sanctions following Russia's invasion of Ukraine, and the aircraft initially relies on the AL-41F1 engine, which does not offer full supercruise capability (the ability to sustain supersonic flight without using afterburners) until the more advanced Izdeliye 30 engine becomes available.

While the Su-57's reported unit cost is significantly lower than that of an F-35, this difference may reflect limitations in the incorporation of cutting-edge technologies.

This iterative design philosophy contrasts with the approach taken by the United States and China. The U.S. transitioned from the fourth-generation F-15 Eagle to the distinctly different, stealth-focused F-22. China's development path led to the J-20, which features a tailless design, a significant departure from previous generations.

Russia, however, appears to have remained committed to the foundational Su-27 architecture. Some reports also suggest a lack in some features those are standard in Western fighter aircrafts.

It may be a lack of resources—Russia’s $100 billion annual defence budget is significantly smaller than the U.S.’s $800 billion—or it may be a strategic choice. But the final product does not appear cutting edge.

 

[sanket]

Nice comparison, but F-22 + F-35 = Su-57 (22 + 35) = 57. Only time will tell which one is better, only in the air, and I'm not comparing them based on an article. Already, Ukraine and NATO burnt their fingers by underestimating Russian weapons, and now they want to stop the war. Ha ha ha!

 

[Somebody]

Nashik plant could very well be used to make these, as both Su-30 and Su-57 have the same lineage. But we don't need more than 36 for us; maybe we can make Su-57 for exports.

 

[SK]

I think it would've been better if the Russians had considered developing a single-engine jet with the same engine as the Su-27/30/35 to replace the aging MiG-29.

This would've allowed them to achieve an F-15 & F-16 combo, allowing cheaper operational capabilities & improved logistics.

They should've opted to develop the MiG-35 & a stealth jet, sharing the engine, like RD-33 (MiG-29), that could be used for both the Russian Air Force & Navy.

The Russians should've focused on optimizing their existing resources, rather than overexerting themselves.

They could've refurbished & sold the aging MiG-29s to African & Middle Eastern nations at a cheaper price to fund their programs.

The best Russia can do right now is to cooperate with China to develop anti-stealth technologies that are more affordable than operating stealth-jet, like ground-based radars, AWACS, ship radars, etc.

 

[Max G]

Nonsensical hit piece written by a pathetic ignoramus. It ignores all the features the Su-57 uses to reduce RCS and posts the moronic claim that its RCS is between 0.1-1 meters. And insinuating that the Su-57 design is a sign of stagnation (in that case, the F-22 and F-35 are also stagnant designs, the F-22 being a stealthed F-15 while the F-35 is a stealthed F-105) is idiotic at best.Installing French and Israeli avionics isn't a part of "design evolution." The design remained the same. Just added more strike capability. Su-57 avionics make the Su-30MKI look archaic.The AL-41F1 was supercruise-capable from the get-go, and with that engine, it can do at least Mach 1.4 without burner.

 

[Nahian Ramim]

Su-27 design is, without doubt, a superb 4th generation design. The reason they don't want to let go of this design is because it was thought the peak of fighter aircraft design reached its end with Su-27 (can't disagree for 4th gen aircraft designs), but it lacked one thing, and that was stealth capabilities. And stealth, in the 21st century, is important for strike missions and BVR fights due to advancements in radar and SAMs.

 

[Hari Sud]

There is no stagnation in Su-57 design. It is built for maneuverability. Which F35 is not. The F35 is radar evasion, that will not last long as newer radars will break that stealth feature.

 

[Yes]

There is no stagnation in Su-57 design. It is built for maneuverability. Which F35 is not. The F35 is radar evasion, that will not last long as newer radars will break that stealth feature.

I highly doubt Su-57s stealth RCS capabilities and its Sensor Fusion prowess, 2 very important features inorder to be categorised as a legitimate 5th Gen Jet fighter.

 

[Somebody]

I highly doubt Su-57s stealth RCS capabilities and its Sensor Fusion prowess, 2 very important features inorder to be categorised as a legitimate 5th Gen Jet fighter.

We will not get F35 until we shed at-least $50Bln to buy other stuff, so it worth wasting $50Bln to get 36 F35, our best second choice is SU-57.

 

[kunites]

Su-57 is, at best, a 4.5+ gen aircraft. Its RCS is nowhere near a 5th gen fighter. However, it can be a great choice for the Indian MRFA deal, as it can outperform Rafales in range, payload, and maneuverability, besides costing much less. It can be equipped with cutting-edge GaN AESA radars developed in India and weapons like Rudram and Gandiv to make it a very potent platform until our own AMCA is mature. However, timely supply from Russia can be an issue for the IAF.

 

[tipoo2]

Nice comparison, but F-22 + F-35 = Su-57 (22 + 35) = 57. Only time will tell which one is better, only in the air, and I'm not comparing them based on an article. Already, Ukraine and NATO burnt their fingers by underestimating Russian weapons, and now they want to stop the war. Ha ha ha!

That's one way to put it. Russia being at a stalemate for years with a much smaller country, that itself largely had old Soviet defenses, is another. Meanwhile, the F-35 took out all of Iran's air defenses while they could only sit there with their "circ'ed" members in hand.

 

[tipoo2]

There is no stagnation in Su-57 design. It is built for maneuverability. Which F35 is not. The F35 is radar evasion, that will not last long as newer radars will break that stealth feature.

Stealth isn't an on off switch to "break". There's only decreasing detection bubbles with lower observability and increasing them with better radars. Low band radars can detect stealth aircraft are in the region just fine, but lack the precision to guide a missile to the right meter squared of airspace to take one down. The F35 will still get first look first kill on any other platform save the F22 perhaps.

 

[CZAR]

Russian thinking is, let's improve the existing concept to the max and make sure that it works before they commit to full-scale production. Americans, they go to a completely new concept and full-scale production, and fix problems on the fly, aka F-35, 60% ready rate, and many problems with software and hardware. The SU-57 is war-tested in Syria and Ukraine, but the F-22 and F-35 are only good in Lockheed Martin commercials.

 

[Sandeep]

It’s obvious that the Sukhoi 57 is much better as it’s a more modern jet, stealth capability, stealth paint, faster engine, better avionics, better jet computer, better EW/ESM, better software etc.

India now needs to start the Super Sukhoi upgrade program to make it more modern and strong combat capability etc.

 

[Anant]

Su-57 is, at best, a 4.5+ gen aircraft. Its RCS is nowhere near a 5th gen fighter. However, it can be a great choice for the Indian MRFA deal, as it can outperform Rafales in range, payload, and maneuverability, besides costing much less. It can be equipped with cutting-edge GaN AESA radars developed in India and weapons like Rudram and Gandiv to make it a very potent platform until our own AMCA is mature. However, timely supply from Russia can be an issue for the IAF.

Not that the Rafale isn't very expensive for an aircraft in general, but we don't quite know how much the Su-57 would theoretically cost. Moreover, as we have seen with Russian weapon systems, buying them is far cheaper than owning them, since you get reduced serviceability and the like with these weapon systems.

 

[Anant]

I think it would've been better if the Russians had considered developing a single-engine jet with the same engine as the Su-27/30/35 to replace the aging MiG-29.

This would've allowed them to achieve an F-15 & F-16 combo, allowing cheaper operational capabilities & improved logistics.

They should've opted to develop the MiG-35 & a stealth jet, sharing the engine, like RD-33 (MiG-29), that could be used for both the Russian Air Force & Navy.

The Russians should've focused on optimizing their existing resources, rather than overexerting themselves.

They could've refurbished & sold the aging MiG-29s to African & Middle Eastern nations at a cheaper price to fund their programs.

The best Russia can do right now is to cooperate with China to develop anti-stealth technologies that are more affordable than operating stealth-jet, like ground-based radars, AWACS, ship radars, etc.

The Su-27 and MiG-29 were the USSR's high-low combination, similar to the F-15 and F-16. As it so happens, the Soviets tended not to favour single-engined designs due to reliability concerns back then.

Coming to the MiG-35, it was a dead project from the start. The USSR's collapse put paid to the MiG-29M and MiG-35 projects, and by the time Russia revisited the type, the MiG-29 was already obsolescent. That meant that the aircraft would need a very comprehensive modernisation to actually succeed. Think something along the lines of the F-16 Block 50/52/70/72 variants as compared to the F-16 Block 10/15 variants. The problem here was that Russia did not modernise the aircraft enough, which meant they were trying to export a 1980s-standard jet in the 2010s and 2020s. Moreover, this jet had little to no upgrade potential, and in a world where many nations could easily afford Su-27s or Su-30s or Gripens or FA-50s or F-16s or any other aircraft, the MiG-35 was never going to succeed.

Coming to older MiG-29s, my point still remains: Not many nations were going to go out and buy a MiG-29 in the 2010s. It was an obsolescent aircraft type by this point. Russia did try to get something going with the MiG-29M, but after it was found that jets sold to Algeria had substandard manufacturing, that whole project also died its own death. Oh, and Russia couldn't exactly sell or donate MiG-29s from its own inventory, since they were already shrinking, and both the Su-27 and MiG-29 squadrons were coming up for replacement without a viable replacement.

 

[Anant]

Nashik plant could very well be used to make these, as both Su-30 and Su-57 have the same lineage. But we don't need more than 36 for us; maybe we can make Su-57 for exports.

And who would you export the Su-57 to? Algeria seems to have purchased theirs from Russia. Iran, Venezuela, and North Korea can't afford the type. Half of the nations that can afford and operate the type won't due to threat of sanctions as well as alternatives being available.

 

[Saptarshi Dasgupta]

Sukhoi 57 is the world's best 5th Gen-minus, or 4.5 Gen++, aircraft; better than Rafale, Gripen E, Eurofighter, and better than F-35 and J-20 in many aspects. I would say get 40 F-35s and then build 114 Su-57s under TOT with India's Virupaksha or Hawk radar. Will be a game changer.

Rafale is simply too expensive.

 

[Sooryan_101]

Terrible article when it came to reviewing the Su-57's stealth characteristics. The classic misinformation about the Su-57's details, mixed with the T-50 prototype's details, exists. I thought whoever wrote this should have at least cross-checked the details and come across the misinformation.

The PAK FA T-50 is the one with unflushed screws and rivets, while the production variant Su-57 has them flushed. It even RAM coats the IRST, and the engine intakes have a grille-like structure (not easily visible) which dissipates radar wave energy once it enters the intake, preventing the same level of reflection. In fact, even modern Su-57s have an upgraded engine whose nozzles are more like the F-22's. Also, who says the Su-57 lacks HMS? Even ignoring the fact that a specific one exists for the Felon, HMS was something the USSR actively used since their 4th generation fighters, such as MiG-29s, way back in the 80s, something NATO took time to adapt to active service.

The RCS info was mostly derived from the T-50's leaked patent and a 3D model testing of the T-50; obviously, the production model Su-57 has it different.

 

[Speedy13]

I think it would've been better if the Russians had considered developing a single-engine jet with the same engine as the Su-27/30/35 to replace the aging MiG-29.

This would've allowed them to achieve an F-15 & F-16 combo, allowing cheaper operational capabilities & improved logistics.

They should've opted to develop the MiG-35 & a stealth jet, sharing the engine, like RD-33 (MiG-29), that could be used for both the Russian Air Force & Navy.

The Russians should've focused on optimizing their existing resources, rather than overexerting themselves.

They could've refurbished & sold the aging MiG-29s to African & Middle Eastern nations at a cheaper price to fund their programs.

The best Russia can do right now is to cooperate with China to develop anti-stealth technologies that are more affordable than operating stealth-jet, like ground-based radars, AWACS, ship radars, etc.

They have. It's the Su-75 Checkmate single engined fighter