Modern Day

Is the Su-57 Felon a 4.5 or 5th Gen Aircraft?

The Su-57 Felon stands as a testament to Russia’s advanced aerospace capabilities, embodying the pinnacle of stealth, speed, and technology.

This multirole fighter aircraft, developed by Sukhoi, represents Moscow’s response to Western counterparts such as the F-22 Raptor and F-35 Lightning II. Its design prioritises stealth, supercruise, supermanoeuvrability, and advanced avionics, setting new standards for air superiority.


Development and Design

The inception of the Felon, Russia’s ambitious venture into fifth-generation fighter technology, traces back to a strategic move to counterbalance Western aerial superiority. The early 2000s marked a period where the Russian military, recognising the evolving dynamics of modern warfare, initiated the quest for a sophisticated airborne platform.

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This led to the PAK FA programme, under which Sukhoi, a name synonymous with Russian aeronautical excellence, emerged as the frontrunner. The vision was clear: to craft an aircraft that would blend speed, stealth, and advanced avionics into an unparalleled air superiority fighter.

The Felon is extremely agile, despite her size.
The combat effectiveness of the Su-57 is unproven. Photo credit – Rulexip CC BY-SA 3.0.

Sukhoi embarked on a design journey that placed a premium on reducing radar visibility while not compromising on aerodynamic performance. The Su-57’s airframe employs state-of-the-art composite materials, accounting for a significant portion of its structure.

These materials not only diminish the aircraft’s radar cross-section but also contribute to weight reduction and structural strength, enabling the Su-57 to execute extreme manoeuvres.

The design team also innovated with the aircraft’s aerodynamics, incorporating features like a blended wing body configuration and leading-edge root extensions. These design choices enhance the Felon’s lift-to-drag ratio, a critical factor in maintaining energy during dogfights and improving overall manoeuvrability.

The aircraft’s internal carriage of weapons further aids in preserving its stealth profile, ensuring it remains undetected as it closes in on its targets.

Stealth Reimagined

The aircraft’s airframe employs composite materials extensively, which absorb radar waves rather than reflecting them back to the source. This choice of materials, combined with the airframe’s geometric design, plays a pivotal role in diminishing the RCS.

The Su-57’s structure integrates radar-absorbent materials (RAM) in key areas to further reduce its detectability. These materials are not uniformly applied but strategically placed where they can offer the most benefit in terms of reducing radar reflections.

The Felon is supposedly 5th Gen thanks to its stealth capabilities. However some sources report it isn't as stealthy as Russia claims. Photo credit - Dmitry Terekhov CC BY-SA 2.0.
The Felon is supposedly 5th Gen thanks to its stealth capabilities. However, some sources report it isn’t as stealthy as Russia claims. Photo credit – Dmitry Terekhov CC BY-SA 2.0.

Another significant aspect of the Su-57’s stealth profile is its internal weapons bays. By housing weapons internally rather than externally, the aircraft maintains a smoother, more aerodynamic shape, which significantly reduces radar detection. T

his design choice eliminates hardpoints where ordnance would traditionally mount on external pylons, thereby reducing the aircraft’s overall radar signature.

The Su-57’s engine inlets and nozzles also contribute to its stealth capabilities. Designers have carefully shaped these components to minimise the aircraft’s infrared signature, making it more challenging for infrared search and track (IRST) systems and heat-seeking missiles to detect and lock onto the aircraft.

The engines themselves are designed with reduced heat signatures, and the aircraft employs cooling measures to further lower its infrared emissions.

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Aerodynamically, the Felon features a blended wing body design, which helps in managing radar reflections. The aircraft’s leading edges are carefully angled to deflect radar waves away from the source, and its overall shape is optimised to reduce detectable radar returns from multiple angles. This ensures that the aircraft remains stealthy not just head-on but from side angles as well.

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Central to its avionic prowess is the aircraft’s radar system, which employs cutting-edge technology to offer unparalleled situational awareness and multi-target engagement capacity. This radar system, with its active electronically scanned array (AESA), can simultaneously track and engage numerous targets, offering the pilot a comprehensive battlefield overview.

In addition to its radar capabilities, the Su-57’s avionics suite encompasses a wide array of sensors and electronic warfare systems designed to dominate the electromagnetic spectrum.

These include infrared search and track (IRST) systems and electronic support measures (ESM) that enable the aircraft to detect, track, and engage targets beyond the reach of traditional radar, while also providing a robust defensive capability against electronic threats.

The Felon's radar on display at MAKS 2009. Photo credit - Allocer CC BY-SA 3.0.
The Felon’s radar on display at MAKS 2009. Photo credit – Allocer CC BY-SA 3.0.

Combining radar, IRST, and sensor data into a unified view significantly enhances combat efficiency. This integration equips the Su-57 for challenging environments by giving the pilot instant, crucial data for rapid decisions. Its advanced cockpit, with helmet-mounted displays, projects essential flight and target details onto the pilot’s visor for peak awareness.

Moreover, the Felon leverages artificial intelligence (AI) to enhance its operational capabilities. AI algorithms process vast amounts of data from the aircraft’s sensors to identify threats, suggest optimal attack vectors, and manage electronic warfare tactics.

This AI assistance allows the pilot to focus on mission-critical tasks, reducing workload and enhancing decision-making efficiency in the heat of combat.

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The aircraft also incorporates secure communication systems that enable it to network with other assets on the battlefield, including drones, satellites, and ground forces. This network-centric warfare capability ensures seamless information sharing and coordination, amplifying the effectiveness of joint operations.


Felon’s armament capabilities stand at the forefront of its design, ensuring it can undertake a wide range of combat missions, from air superiority to ground attack, with unmatched proficiency.

Central to its arsenal is a sophisticated internal weapons bay, designed to carry a variety of advanced munitions while maintaining the aircraft’s stealth profile. This design approach ensures the Su-57 can deliver its payload with precision, without compromising its low radar cross-section.

The R-37M is huge and can travel huge distances. Photo credit - Vitaly Kuzmin CC BY-SA 4.0.
The R-37M is huge and can travel huge distances. Photo credit – Vitaly Kuzmin CC BY-SA 4.0.

At the heart of its air-to-air combat capabilities, the Felon carries a selection of advanced missiles, including the R-77 medium-range missile and the R-37M long-range missile. These missiles are capable of engaging targets at significant distances, allowing the Felon to neutralise threats before they can pose a real danger.

For engagements at closer ranges, the aircraft is equipped with highly manoeuvrable short-range missiles that provide it with a decisive edge in dogfights.

Air to Ground

In addition to its air-to-air arsenal, the Felon boasts a formidable array of air-to-ground munitions, enabling it to perform precision strike missions against ground and sea targets.

This includes the latest generation of guided bombs and missiles, such as the Kh-38M tactical ground missile and the Kh-58UShKE anti-radar missile, designed to suppress and destroy enemy air defences and vital infrastructure. The integration of these weapons allows the Su-57 to conduct deep penetration strikes, taking out high-value targets behind enemy lines with surgical precision.

For close-in combat scenarios, the Su-57 is equipped with a 30mm cannon, providing the pilot with a highly effective weapon for strafing runs against ground targets or in a last-ditch defence against aerial opponents. This cannon is seamlessly integrated into the aircraft’s design, ensuring it does not detract from the Su-57’s stealth capabilities.

The Felon’s armament system is further enhanced by its advanced targeting systems, which include laser, infrared, and satellite guidance for its munitions, ensuring high accuracy and lethality.

The aircraft’s avionics and sensor suite work in concert to identify, track, and prioritise targets, providing the pilot with real-time information to execute complex attack scenarios.

The Su-57 is not just for air superiority, but can perform ground attacks too. Photo credit - Anna Zvereva CC BY-SA 2.0.
The Su-57 is not just for air superiority but can perform ground attacks too. Photo credit – Anna Zvereva CC BY-SA 2.0.

The Felon isn’t Perfect

By early 2023, reports indicated that a limited number of Su-57s had been delivered to the Russian Aerospace Forces due to several issues with getting the Felon operational.

The first serial production Su-57 was reportedly delivered in December 2020, marking a significant milestone in the aircraft’s development program. Subsequent deliveries have been ongoing, albeit at a pace influenced by various factors, including production rates, testing outcomes, and budgetary considerations.

One of the most significant challenges has been the development of the Su-57’s engines. Initially, the aircraft flew with the Saturn AL-41F1 engines, which were essentially an upgraded version of the engines used in the Su-35.

While these engines were capable, they did not fully meet the performance criteria for a fifth-generation fighter’s power and efficiency, particularly in terms of supercruise capability and fuel efficiency.

The development of a new engine, the Izdeliye 30, intended to provide the Su-57 with enhanced performance, including better supercruise capability, reduced radar signature, and improved fuel efficiency, faced delays and technical hurdles.

The Felon has said many difficulties before entering service. Photo credit - Anna Zvereva CC BY-SA 2.0.
The Felon has said many difficulties before entering service. Photo credit – Anna Zvereva CC BY-SA 2.0.

While the Su-57 incorporates stealth technology, there have been discussions regarding its stealth capabilities compared to other fifth-generation fighters like the F-22 and F-35. Some analyses suggest that while the Su-57 has reduced radar cross-section (RCS) from certain angles, it may not be as stealthy in all aspects as its Western counterparts.

Money Problems

The Su-57 program has faced production delays and financial constraints. Developing a fifth-generation fighter is an enormously costly endeavor, and despite the strategic importance of the Su-57, the program has not been immune to budgetary pressures.

This has impacted the pace of development and testing, as well as the scale of production plans. Initially, large-scale procurement plans were scaled back, reflecting these financial and technical challenges.

Operational units, such as the 929th State Flight-Test Centre named after V.P. Chkalov in Akhtubinsk and later the 23rd Fighter Aviation Regiment based in Dzemgi, Komsomolsk-on-Amur, have been identified as the first recipients of the Su-57.

These units are pivotal for the integration, testing, and operational deployment of the Su-57 within the Russian Aerospace Forces.

Operational History

Since its maiden flight in 2010, the aircraft has undergone a rigorous testing and evaluation phase, aimed at validating its advanced capabilities and ensuring it meets the stringent requirements set forth for fifth-generation fighters.

The Su-57 upside down.
There is a planned export version – the Su-57E. Photo credit – Anna Zvereva CC BY-SA 2.0.

Following its first flight, the Felon embarked on an intensive testing program that scrutinised every facet of its design, from stealth and avionics to armament and manoeuvrability.

These tests took place across various environments and conditions, simulating the complex scenarios the aircraft would face in actual combat. The objective was clear: to refine and perfect the Su-57, ensuring it could reliably execute its intended roles of achieving air superiority and conducting precision strike missions.

The Su-57’s testing phase also served as an opportunity to demonstrate its advanced features, including its supercruise capability, allowing it to fly at supersonic speeds without the use of afterburners, thereby conserving fuel and extending its operational range.

Additionally, the aircraft’s supermanoeuvrability was put to the test, showcasing its ability to perform complex aerial manoeuvres beyond the capabilities of previous generation fighters.

Entering Service

In December 2020, the Felon officially entered service with the Russian Air Force, marking a pivotal moment in Russia’s military aviation history. This induction signified the culmination of years of development and testing, affirming the Su-57’s readiness to undertake its role as the cornerstone of Russia’s air combat capabilities.

The aircraft’s entry into service also underscored Russia’s commitment to maintaining a competitive edge in the realm of stealth and fifth-generation fighter technology.

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The Su-57’s operational deployment has been accompanied by continued development efforts, aimed at enhancing its capabilities and integrating new technologies. This includes the development of more advanced versions of the aircraft, equipped with improved engines and avionics, as well as the exploration of its use as a platform for unmanned aerial vehicles (UAVs).

These efforts reflect a broader strategy to ensure the Su-57 remains at the cutting edge of military aviation technology, capable of adapting to the evolving landscape of aerial warfare.

Moreover, the Su-57 has attracted international attention, with several countries expressing interest in acquiring the aircraft or collaborating in its development. This international interest not only highlights the Su-57’s advanced capabilities but also positions Russia as a key player in the global defence market, capable of producing a fifth-generation fighter that rivals those developed by Western powers.