The Sukhoi Su-57, NATO reporting name ‘Felon’, is the very first fifth-generation stealth fighter aircraft in Russian service, but is this aircraft as fearsome as some aviation commentators have publicly stated?
The Felon has had a horribly convoluted development program, with many delays attributable to technical issues and the volatile nature of the Russian economy since 1999, and the type has only been formally introduced into service recently, and only in small numbers to date.
Conceived as a lower-cost but far more capable design alternative to the failed MiG 1.44 concept fighter program, the Felon project underwent several conceptual study programs before a final design was agreed on for prototyping and pre-production manufacture and testing.
Along this meandering development path, the project lost its only national partner when India withdrew from a collaborative program to produce a variant for its use, and Vietnam delayed the planned acquisition of the platform as well.
In both cases, the build quality and stealth characteristics were mentioned as major reasons for not continuing with the project or delay on the part of Vietnam, which may point to the Felon not being the reputed ‘silver bullet’ that can successfully combat Western stealth fighters currently in service.
Design and Development
Even as new Soviet fourth-generation fighters were taking to the air in the late 1970s, the Soviet General Staff was looking towards the future of aerial warfare.
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Realising that their economic system was increasingly causing Russian aircraft design to lag behind the West in certain areas, the government tasked Soviet Military Intelligence (GRU) to steal as many industrial secrets as they could from the West, in a desperate bid to stay level in several technical fields.
Nowhere was this more urgent than in the military aviation sector, especially in the emerging technology of ‘stealth’.
In 1979 the government commenced the ‘I-90’ Project, which was to provide the Soviet Union with a new-generation fighter able to fly and fight against the latest American designs, including a rumoured Advanced Tactical Fighter (ATF) project that would eventuate as the F-22 Raptor.
The Mikoyan factory entered a design model known as the MiG 1.44 and showcased a technology demonstrator airframe in 1983, but despite some good features and innovations, the program encountered enough difficulties that it was closed down in the late 1980s despite considerable effort.
The project concept was reworked as the ‘I-21’ Project in the 1990s, and Sukhoi entered the competition with a design known as the PAK-FA.
With the PAK-FA design being deemed superior to other competing offerings, Sukhoi got the nod in April 2002 to continue the development of a stealth fighter, and the prototype modelling received an internal company name of T-50.
Sukhoi used existing airframes to prove several concepts for the Felon, including the Su-47 testbed aircraft being utilised to test the planned covered internal weapons bays in the Su-57.
Also, building on the success of its Flanker model already in service, the company used the Su-27M prototype aircraft to test flight control systems and power plants, including thrust vectoring.
As a backup plan and to reduce costs and risk the company decided to also use some of this new technology in a new model of the Flanker, and this was adopted into service as the Su-35S ‘Super Flanker’ in 2014.
In 2009 the final design for the Felon was approved, and the first order for ten prototypes was confirmed soon after this date.
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The first flight of a prototype took place in January 2010, and a rigorous testing program was established, but technical problems, material deficiencies and Russian economic difficulties caused many delays with the project.
The assistant Russian Minister of Defence did not help matters when he praised the Su-35S and stated that it could perform any mission as competently as the Felon, and all it lacked was the stealth aspects of the Su-57.
In 2007 the Indian Air Force (IAF) joined the PAK-FA program to jointly produce a two-seat version for India’s Fifth Generation Fighter Aircraft (FGFA) procurement program.
A foreign partner had been sought by Russia to secure lucrative export orders, and to defray development costs, in 2010 both parties pledged to contribute $6 billion for research and manufacturing costs.
However, by 2014 the IAF was being very vocal about their concerns about build quality, technical shortcomings and national share of the manufacturing process, and formally left the project in 2018. The only other current foreign order for the type is from Vietnam but is progressing slowly due to Vietnamese criticisms about build quality.
A small order for two production aircraft for Russian service was signed in 2018, and moderate follow-up orders were expected in the decade to follow but all this changed when Vladimir Putin became the president of Russia.
In May 2019 a firm order for 76 units was signed, as negotiations between Sukhoi and the government had lowered the cost of production aircraft.
The first deliveries were announced in December 2020, despite the unfortunate crash of the first production aircraft during factory trials in December 2019.
There are currently two variants of the base Su-57, with one offered for export to potential foreign customers, and a version testing and introducing new avionics, capabilities and power plants.
The Su-57E is the export model, and besides the small Vietnamese order is also the subject of interest from several other nations, but no firm orders have been announced to date.
The Su-57M is a variant with upgraded avionics and mission roles, as well as new engines boasting a large increase in both dry and augmented power settings, and the first flight of this model was expected in 2022.
The PAK-FA concept had to encompass some strict requirements, and the resultant design showcased a very large aircraft as a result of all these technical demands being fulfilled.
Sukhoi drew on the success of the Su-27 as a large, heavy fighter for some of the Felon’s design features, and the result was a large airframe indeed.
Empty, the airframe weighs in at 18,000 kilograms (39,683 pounds) and the gross loaded mass is reported as 25,000 kilograms (55,116 pounds), but this can be exceeded with certain ordnance loads.
The Felon is equipped with two Saturn AL-41F1 augmented turbofans with thrust-vectoring nozzles. These engines each develop 20,000 pounds of thrust in full military power, and an incredible 33,100 pounds of thrust in emergency reheat, giving the Felon a maximum speed of Mach 2 or 2,135 km/h (1,327 mph).
The aircraft can be refuelled in flight, and with two drop tanks the ferry range is over 4,500 kilometres. The airframe is rated to 9G+ for combat manoeuvring, and when loaded to maximum gross weight the power-to-weight ratio of the Felon is 0.99.
The Su-57 is armed with a Gryazev-Shipunov GSh-30-1 30 mm autocannon, with 150 rounds supplied for this weapon. The Felon has twelve hard points, and the six that are shielded by internal bay covers can carry a very respectable 7,500 kilograms of ordnance in complete stealth.
The Su-57 is able to carry and deploy nearly every weapon in the Russian inventory and can employ guided and dumb bombs, air-to-air and air-to-surface missiles, rocket pods or a combination of all these weapon options.
The Felon has modern avionics with AESA radar, modern combat systems for both offensive and defensive targeting, digital data links and navigation equipment, and also has been observed fitted with Infra-Red Search & Track (IRST) turrets for off-bore shooting of infra-red guided missiles.
A rumoured but as-yet-unseen two-seat version for multi-role tasking is supposedly in development for both Russian and foreign use.
Procurement and Service Employment
The Su-57 has been observed operating in small numbers (2-4?) during the Syrian civil war in 2018. The type supposedly flew ten combat missions in the region, including one where a Su-57 fired an air-to-ground missile at ISIS targets.
These sorties were used by the Russian defence ministry as operational test flights, and as these were stated as being completely successful they led to the first firm order of aircraft for Russian use.
Russia stated that it has used the Su-57 in combat over Ukraine since the February 2022 invasion, and has successfully employed the type in strike, aerial combat and Suppression of Enemy Air Defences (SEAD) missions, but this could not be independently confirmed.
British Military Intelligence has stated that the small number of Su-57s are based over 500 kilometres from the Ukrainian border, and do not operate outside of Russian airspace.
This is because Ukraine’s air defences are robust and deadly, and the Russians fear the aircraft’s reputation could be damaged by combat losses, as well as the compromise of any technical secrets should a Felon be brought down in Ukrainian-controlled territory.
Further procurement of the Su-57 is becoming problematic for several reasons: sanctions on Russia after the Crimean annexation in 2014 sharply increased after the Russian invasion of Ukraine in 2022.
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This has caused serious problems for the Russian aerospace industry, with access to advanced microchips and other electronic components being savagely curtailed causing delays to large-scale production of the Felon. In addition, as Russia is banned from any payment system using the US dollar for transactions, the Su-57 export program has serious commercial roadblocks to any firm orders for the aircraft placed in its way.
The Sukhoi Su-57 Felon stealth fighter is a major cause for concern by Western militaries, but the potential threat of this aircraft may not be as ominous as first thought.
Some interesting photos of the wings of the Felon have been circulating online showing stealth-unfriendly counter-sunk screws exposed on the wing’s surface, but whether this is deliberate or before a final coating/surface is applied for stealth reasons has not been made clear.
Some evaluations of the Felon state that the airframe’s all-aspect stealth capabilities are nowhere as advanced as Western fighters such as the F-22 and the F-35.
These observations may be backed up by evaluations of the Su-57 from think tanks and Western militaries, which state that the program has great potential, but is maybe let down by potentially inferior technologies used in both the avionics and stealth fit-outs for production aircraft.
Only time will tell if the Felon fulfils its design potential, but with the West soon to field sixth-generation fighter designs, the Su-57 may find itself outmoded even before large-scale deployment occurs. It would be ironic if its non-stealthy ancestor the Su-35S Flanker ends up with a more distinguished service record and far greater sales success.
- Crew: 1
- Length: 20.1 m (65 ft 11 in)
- Wingspan: 14.1 m (46 ft 3 in)
- Height: 4.6 m (15 ft 1 in)
- Empty weight: 18,000 kg (39,683 lb)
- Gross weight: 25,000 kg (55,116 lb) normal takeoff weight, 29,270 kg (64,530 lb) at full load
- Max takeoff weight: 35,000 kg (77,162 lb)
- Powerplant: 2 × Saturn AL-41F1 afterburning turbofan, 88.3 kN (19,900 lbf) thrust each dry, 142.2 kN (32,000 lbf) with afterburner, 147.1 kN (33,100 lbf) in emergency power
- Maximum speed: Mach 2 (2,135 km/h; 1,327 mph) at altitude
- Range: 3,500 km (2,200 mi, 1,900 nmi) subsonic, 4,500 km from 2 outboard fuel tanks
- Service ceiling: 20,000 m (66,000 ft)