The T-50-1 making its first public demonstration at the MAKS 2011 air show, during which it developed a structural fault All images by Piotr Butowski unless stated

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Sukhoi Su-57

Right: Mikhail Strelets, the head of the Sukhoi design bureau and the Su-57’s chief designer since 2014

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on the loose!

Russia’s next-gen fighter, the Sukhoi Su-57, looks as dangerous as its nickname would suggest. Piotr Butowski charts the long

gestation period preceding its unveiling in December 2020

In December 2020, just a week before Christmas, Russian Aerospace Forces (VKS) unwrapped its highly-anticipated

present at Dzyomgi airfield in Komsomolsk-on-Amur in eastern Russia. The new-generation Sukhoi Su-57 fighter

may not have arrived on a sled driven by a fat man with a white beard, but the excitement was palpable. After 11 years of testing, the Su-57, now widely-known as ‘Felon’, was finally entering service. The VKS will take delivery of four more fighters in 2021 and, by 2028, three units will be equipped with 24 Su-57s each.The origins of the lethal-looking Sukhoi

Su-57 can be traced back even further, to the mid-1980s, when the Soviet Union began to develop a new air superiority fighter just after the MiG-29 and Su-27 had entered military service. However, in the 1990s, it became

clear that neither of the new prospects, the Mikoyan MFI and Sukhoi Su-47 fighters, would go into production. In April 2001, Russia’s Air Force announced

a competition to design a concept for the Future Air Complex of Tactical Aviation (PAK FA). The competition saw two projects go head-to-head: Sukhoi’s T-50 fighter, with a maximum weight of 28-30 tonnes, and Mikoyan’s smaller E-721, which retained the canard layout of the MFI with a small forewing placed ahead of the main fixed wing.The two projects pursued

two different philosophies. Sukhoi proposed a ‘maximum capability’ fighter in the upper middle class, while MiG

proposed a ‘minimum essential’ fighter for a more reasonable cost. Nikolai Nikitin, head of MiG, said at the time that $1.3bn per year from 2010-2025 would be enough to purchase and operate the necessary number of aircraft. In contrast, the heavier Sukhoi

would cost $2bn a year. On April 26, 2002, a Russian

government commission declared the Sukhoi T-50 fighter to be the winner of the PAK FA competition. Major General Sergey Kolyadin, chairman of the military-scientific committee of the Russian Air Force, said Sukhoi won because “its concept was better according to a whole complex of criteria.” On July 21, 2003, Sukhoi

received a formal contract

‘Felon’

During the first public demonstration at the MAKS 2011 air show, the T-50-1 suffered a structural crack; the repairs took over a year

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Sukhoi Su-57

from the Russian Ministry of Defence for the development work to cover the design, construction and testing of T-50 prototypes. Almost 18 months later, on December 10, 2004, the preliminary design for the aircraft was approved. Alexander Davidenko was programme director and chief designer of the T-50 fighter in the Sukhoi design bureau, a position he held from 2002 until 2014, when he was replaced by Mikhail Strelets. Sukhoi’s KnAAZ plant in Komsomolsk-on-Amur was tasked with building the T-50 prototypes.

PrototypesThe first prototype T-50-1 undertook its maiden flight in Komsomolsk-on-Amur on January 29, 2010, with test pilot Sergey Bogdan at the controls. On April 8, 2010, following a few further flights, T-50-1 was transported aboard a giant Antonov An-124 airlifter to Sukhoi’s test site in Zhukovsky, near Moscow, the only place with the necessary infrastructure to support advanced trials. The T-50-1 prototype was used for flight

handling evaluation and had no mission systems. After more than a year of testing, on March 9, 2011, it broke the speed of sound for the first time.

The first public display of the fighter occurred at MAKS air show in August 2011, where both T-50-1 and T-50-2 performed. The aircraft could only be seen from a distance in flight; on the ground they were obscured by large screens. The next prototype, T-50-3 (which first flew on November 22, 2011) was the first to be fitted with mission sensors, including a less

capable N036 radar, with only a single front antenna. On July 26, 2012, the radar was switched on for the first time in flight. In 2012-2013, two more prototypes were

built, T-50-4 and T50-5. The trials of the first five prototypes experienced problems with the strength of the airframe – during the MAKS air show flight of 2011, T-50-1 had suffered a structural crack and further

The Sukhoi T-50-2 lands at the MAKS air show in August 2011. Being an era when aircraft from the west participated in Russian air shows, a USAF F-15E Strike Eagle is visible in the background

The second T-50-2 prototype. Between December 2012 and May 2013, it underwent

modernisation in the Sukhoi workshops

T-50-3 is the first prototype fitted with the N036 radar (with front X-band antenna only) and part of the 101KS Atoll electro-optical sensors. On July 26, 2012, the radar was switched on for the first time in flight

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problems were revealed when the airframe was dismantled. These weaknesses were initially addressed using various strengthening additions to the airframes, but eventually they led to a deeper reworking of the design of the aircraft. The upgrades took more than a year and T-50-1 didn’t resume test flights until September 2012.Further problems ensued. On several

occasions the aircraft had to land with one engine shut down. T50-5 suffered the heaviest damage when it caught fire on the runway in Zhukovsky after landing on June 10, 2014 – unfortunate timing because it coincided with a presentation for an Indian delegation. It wasn’t until October 2015 that the aircraft, now designated T50-5R, resumed its test flights after repair.

Stronger airframesInitially, the program planned to use six test aircraft; followed by serial production of the fighter. However, problems surrounding inadequate structural strength forced these plans to change. In October 2012, a decision was made to

build another batch of test aircraft according to a revised design. The first strengthened

aircraft, T-50-6, made its maiden flight on April 27 2016, two-and-a-half years after the fifth. Then, during 2016 and 2017, further new prototypes followed, bearing the numbers T-50-8 through T-50-11. The last two of these aircraft were fully equipped with mission sensors and avionics, with T-50-11 effectively becoming the pattern for series production.

Finally, in July 2017, the T-50 officially received its military Su-57 designation. With the construction of the second five

prototypes, the burden of testing moved from the aviation industry test centre in Zhukovsky to the military test centre of 929th GLITs at Akhtubinsk, where state acceptance trials (GSI) are conducted. The first stage GSI-1 trials ended with the signing of a relevant act

A sharp take-off for the T-50-2 prototype during the Russian Air Force’s 100th anniversary show in August 2012. Measurement lines were painted on the nose to analyse the aerial refuelling operation

Five of the later prototypes, including the T-50-8 seen here, had strengthened internal structure

The T-50-1 performing at MAKS 2019 in a

new pixelated livery applied to most Su-57 aircraft in spring 2018

Sukhoi Su-57

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on May 12, 2018, that formally provided the clearance to begin production of an initial batch of fighters. The second stage GSI-2 trials, which

provided the clearance for operational service, started in 2018, with completion planned for 2020. In early May 2020, Yuri Borisov, Russia’s Deputy Prime Minister responsible for the arms industry, announced that the state trials programme had “entered its final phase… more than 3,500 flights have already been performed.”In February 2018, two Su-57s were

deployed to Syria for a two-day evaluation. The purpose of this trip remains unclear. It seems doubtful it was a trial, given that there is not much that can be assessed in two

days. It’s also worth noting the dates the fighters were in Syria: February 22-24. The day in between,

February 23, is Defender of the Fatherland Day in Russia, one of the country’s biggest national holidays. One possible explanation is a state-of-the-nation speech delivered by President Vladimir Putin a week later, on March 1, when he presented new types of Russian armaments, including the Kinzhal airborne strike system and the nuclear-powered Burevestnik cruise missile. It’s possible the

Su-57’s deployment to Syria was earmarked to coincide with this speech, although mention of the aircraft didn’t make the final draft delivered by President Putin. On May 9, 2018, a pair of Su-57 fighters

flew for the first time as part of the Victory Day parade over Red Square in Moscow.

Active serviceLooking back, the early announcements and promises about the Su-57 programme appear rather ridiculous – enthusiastic, but not very realistic. On February 1, 2010, for

The fourth T-50-4 prototype

The third prototype,T-50-3, is now used for evaluation of automatic take-off and landing, as well as navigation and communication systems developed for the Okhotnik unmanned aircraft

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example, President Putin saluted the fighter’s creators shortly after its maiden flight, and claimed the first pre-series fighters would be delivered to the air force’s crew conversion centre at Lipetsk in 2013. By 2015, he added, full-scale production would have started. The Russia’s State Armament Program

for 2011-2020 (GPV-2020) stipulated the acquisition of 52 PAK FA fighters by 2020. For 2021-2025, it looked forward to the production of 150-160 aircraft. But the combination of technical obstacles

in the implementation of the Su-57 program, the unclear position of India and its subsequent withdrawal from the project, Western sanctions following Russia’s annexation of Crimea and, finally, the collapse of oil prices in 2014, all contributed to pushing back deadlines and diminished Russian appetite for the fighter. In March 2015, then Deputy Defence

Minister Yuri Borisov said the military would buy fewer fifth-generation fighters, opting

instead for the cheaper Su-30SM and Su-35 fighters. The country’s promise to buy a dozen Su-57s by 2020 also turned out to be overly optimistic. On August 22, 2018, the United Aircraft Corporation (UAC) was awarded a contract for just two fighters to be delivered to the VKS, one in 2019 and the other in 2020.In December 2019, the KnAAZ plant

in Komsomolsk-on-Amur finished the construction of the first pre-production Su-57 ‘01’ (T-50S-1; c/n 51001), due to be delivered to the VKS later in the same month. However, on Christmas Eve, the aircraft crashed during its handover flight; the pilot, Alexei Gorshkov, ejected successfully. According to the accident report, the crash was due to a

failure with the flight control system. The second model, T-50S-

2, was completed in October 2020 and has now become the first Su-57 handed to the Russian military. Finally, in December 2020, the aircraft was transferred to the 23rd Fighter Aviation Regiment at Dzyemgi air base, the airfield shared by the Komsomolsk-on-Amur plant. It is standard KnAAZ practice for the first batch of a new aircraft to go to its neighbouring unit, where it is easier to access qualified

T-50-5 is the last of the first batch of Su-57 prototypes made according to the initial design. After a fire in June 2014, the aircraft, redesignated T50-5R, resumed test flights in October 2015. Here it has a new pixelated livery, introduced in 2018

The T-50-9 prototype being prepared for presentation at MASK 2017. At that time, the aircraft officially received its military name of Su-57

A non-flying T-50-KNS (Kompleksnyi Naturnyi Stend, complex full-scale stand) mock-up presented as the Su-57E ‘057’ export version, on static exhibition at MAKS 2019

Sukhoi Su-57

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maintenance. The same squadron in Dzyemgi was also the first user of Su-35S fighters in February 2014, as well as Su-27 fighters back in December 1984.

Big orderDespite Borisov's frugal approach to procuring the Su-57, on May 15, 2019, Vladimir Putin unexpectedly called for the acquisition of 76 Su-57 fighters. “We need to fully re-equip three Aerospace Force air regiments with the Su-57 fifth-generation advanced air system by 2028,” he said at a conference in Sochi for military and industry management. According to Putin, the current GPV-2027

acquisition program had provided for the purchase of only 16 Su-57 fighters. However, after negotiations, he said that “the involved companies reduced the cost of the aircraft and arms by almost 20%.”This enabled the Government to increase

the order to 76 aircraft “without an increase in costs”, which made observers question the mathematics. A formal order was placed by Russia’s Ministry of Defence with Sukhoi on June 27, during the Army 2019 exhibition in Kubinka, outside Moscow. The first four fighters covered by this

contract are scheduled to be delivered in 2021. The order will certainly help to perfect

the new platform, which could not have been done using either the prototypes or the initial low production run of the aircraft. Moreover, in 2018, Russia began offering the

Su-57E aircraft for export. UAC President Yuri Slyusar claimed in August 2018 that the Su-57 would be “significantly cheaper” than US F-22 and F-35 fighters, although he declined to give any precise figures. During the MAKS 2019 air show, the Su-57E

(actually, a non-flying T-50-KNS mock-up) was personally shown by Putin to Turkish President, Recep Tayyip Erdogan. Two further countries, Algeria and Egypt, have recently purchased significant batches of Russian MiG-29M and Su-35 fighters, so could possibly be interested in the Su-57E.In Asia, Vietnam is the most likely customer.

The rest of the traditional buyers of Russian military technology either want to build similar aircraft indigenously – as China and India do – or cannot afford such an expensive aircraft, a situation in which Russia’s post-Soviet neighbours find themselves.

Su-57 in detailIn May 2020, Mikhail Strelets, head of the Su-57 programme, outlined some of the objectives of the aircraft. Most were typical for a fifth-generation fighter, such as low visibility, supersonic cruising speed and supersonic manoeuvrability. Strelets particularly emphasised the “high level of automation and high intellectualisation of combat operations, as well as interoperability with automated command systems.” The Su-57’s fire control system, for example, “has the ability to omnidirectional and multi-channel use of the weapons.”From the outset, Strelets insisted, the

Su-57 had been conceived as a multi-role jet, combining the functions of a fighter and strike aircraft. As Russia opted for only one type of new fighter, it could not split missions between a heavy aircraft that was optimised for air superiority and a lightweight jet to be used for strike missions.The aerodynamic configuration of the Su-57

is aimed at achieving a high lift-to-drag ratio at supersonic speed, much higher than in the previous generation fighters, which enables supersonic cruise flight without the use of the afterburner. The most identifiable feature of the T-50’s aerodynamic layout is its heavily forward-stretched fuselage side extensions, which extend to large moving flaps on the leading edge. These extensions shift the centre of pressure forward, increasing the

T-50-11 ‘511’ that performed its first flight on August 6, 2017, is considered by Sukhoi as the final model for serial production

The initial series Su-57 (T-50S) under assembly

at the KnAAZ plant

Heading hereSerial c/n Code Delivery date

MM55229 NC7102 61-24 February 7, 2019

MM55230 NC7103 61-25 February 7, 2019

MM55231 NC7104 61-26 May 22, 2019

MM55232 NC7105 61-27 October 30, 2019

The Su-57’s aerodynamic layout features strongly forward-stretched fuselage side extensions that extend to large moving flaps on the leading edge, connected to the fuselage by elastic couplings

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static instability of the aircraft (the greater the instability, the more manoeuvrable the aircraft). This is especially important in supersonic flight, where the centre of pressure naturally shifts rearward and the aircraft becomes excessively stable and less manoeuvrable. Thanks to high static instability, the Su-57 can manoeuvre at a supersonic speed much better than any previous fighter.The Su-57’s fire-control systems

include the Sh121 radio-electronic suite and 101KS electro-optical suite; both systems also perform aircraft self-defence tasks. The Sh121 consists of the N036 radar system, the N036Sh identification friend or foe (IFF) and the L402 electronic countermeasures (ECM) system. The N036 Byelka (squirrel) radar has five active electronically scanned arrays (AESA) that together control airspace within a range of up to +/-135° from the aircraft’s axis. The 101KS Atoll electro-optical suite is

intended to provide full control of the space around the aircraft in the optical range. The Atoll couples a series of sensors, the most prominent of which is the forward 101KS-V infra-red search-and-track (IRST) sight. Four 101KS-U ultraviolet missile-approach

warning sensors (MAWS) cover the whole sphere around the fighter. The next two sensors are the 101KS-O turrets – one on the fighter’s spine and another under the nose – that are both directional infrared countermeasures (DIRCM) to jam missiles’ heat-seekers and conduct all-round surveillance in the optical range. Another 101KS-P comprises a small imaging

IR sensor to aid low-level flying and landing; it is fitted in the forward section of the left,

canoe-shaped underwing missile bay. And, finally, the 101KS-N navigation and targeting pod has been developed for the Su-57.The Su-57 carries its basic ordnance load

inside two large internal weapon bays that are arranged in tandem between the engines. Each bay can accommodate two missiles with a maximum size of 4.2m in length and a 40 x 40cm cross section. Two more missiles

fit inside two so-called ‘quick launch’ bays in the form of oblong underwing fairings; each is for a single R-74M2 (Izdeliye

760) air-to-air missile.Trials of internal-carriage weaponsbegan unexpectedly late, sixyears after the first flight of T-50

prototype. Su-57 fired a missile

from the internal weapon bay for the first time on March 16, 2016, although the type of weapon is unknown. In missions that do not require stealth, the aircraft may carry a heavier armament load, using four pylons under the wing and two more under the air inlets. A 30mm single-barrel cannon with 150 cartridges is located within the starboard wing root.New air-to-air missiles that have been

developed especially for internal carriage are the close-air combat R-74M2 (Izdeliye 760), beyond-visual range R-77M (Izdeliye 180) and very-long (estimated at 300km) range ‘Izdeliye 810’. Series production of the R-77M started in 2019-2020, while the other two are still under evaluation.

Sukhoi Su-57: Estimated statsWingspan 14.1m (46ft 3in)

Length 20.1m (66ft)

Height 4.6m (15ft 1in)

Empty weight 18,000kg (39,683lb)

Nominal take-off weight 25,000kg (55,116lb)

Maximum take-off weight 35,000kg (77,162lb)

Maximum speed Mach 2.0

Supersonic cruising speed Mach 1.3

Maximum supersonic range 810 nautical miles (1,500km)

Maximum range 1,890 nautical miles (3,500km)

Su-57 fires an R-74M2 close-air combat missile from the ‘quick launch’ bay

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Sukhoi Su-57

The most capable long-range, air-to-surface weapon designed specifically for the Su-57 is the Kh-69 missile, which is a Russian counterpart to the MBDA Storm Shadow intended to destroy small, hardened targets of known co-ordinates at 300km or more. The Kh-58UShK anti-radiation missile has folded wing and fins to fit the Su-57’s internal bay; it can reach a range of 245km, flying at high-supersonic speed.The universal Kh-38M air-to-ground missile

flies up to 70km, with guidance variants

including semi-active laser, imaging infrared or active-radar seekers. The Grom (thunder) missile was adapted from the Kh-38M by adding a module with a folding wing to extend the range to 120km. The smallest air-to-ground munition made

specifically for the Su-57 is the 250kg KAB-250L electro-optical guided bomb.

Future Su-57MWith the Su-57 (T-50S) fighter entering production and service, work is underway on

a heavily-modified Su-57M (T-50M) version, which is also known as the ‘second stage’ Su-57 fighter. Formally, Sukhoi received a contract from the Ministry of Defence to modernise the Su-57 on October 29, 2018, although preliminary work began much earlier. Reportedly, the contract provides for the T-50M prototype to begin flight tests in mid-2022, with series production starting at the end of 2024. Probably the most important – and

certainly the most visible – element of this modernisation programme is the fitting of new engines. The current AL-41F-1 (Izdielije 117) turbofan is a radical departure from the AL-31F engine used in Su-27 and Su-30 fighters. The entirely new engine ‘Izdeliye 30’ is a clean-sheet design, which has been specifically developed to offer increased thrust, lighter weight and lower operating costs. On December 5, 2017, the T-50-2LL flying testbed started test flights with its port engine replaced by a demonstrator of the ‘Izdeliye 30’. Deputy Defence Minister Yuri Borisov commented that “with the new engines the characteristics of the Su-57 will improve significantly.” Meanwhile, a research and development

project aimed at upgrading the present AL-41F engine has recently started. This may be an alternative option in the event of a delay in the new ‘Izdielije 30’ programme.

During MAKS 2019, Su-57 demonstrated

a very short run (estimated at below

200m) thanks to the release of the

braking parachute before it touched

down on the runway

Su-57’s radar and electro-optical sensors

provide all-round surveillance, targeting

and self-defence

On 5 December 2017, the T-50-2LL with the port engine replaced by a demonstrator of ‘Izdeliye 30’ started the flight tests

In missions not requiring stealth, the aircraftcan carry armaments on external pylons. Here

is the T-50-1 carrying two Kh-31 anti-ship/anti-radiation missiles and two R-73s for self-defence

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Further readingSu-57 Felon by Piotr Butowski promises to be the ultimate celebration of the ultimate Russian fi ghter. An analyst and journalist specialising in Russian aviation technology, Piotr provides in-depth insight into this groundbreaking aircraft and its immense abilities. The book will be available on February 21, 2021, from shop.keypublishing.com (£14.99).

However, modernisation of the Su-57 will involve more than just the implementation of the new engine. New weapons are being introduced and the fighter’s equipment is being improved. UAC President Yuri Slyusar declared that the Su-57 “will become the basis of a whole family of airplanes, just as earlier the Su-27 became the basis for the creation of a family of modern fighters.” It is reasonable to expect that variations of the

Su-57 will replace Su-33 ship-borne fighters, Su-34 fighter-bombers and MiG-31 interceptors in the distant future. AFM

Above: In May 2014, during the Aviamiks show at the Pogonovo training ground near Voronezh, two Su-57s were fi rst shown to the public with Kh-31, R-77 and R-73 missiles suspended under their wingsBelow: Air-to-surface munitions developed specifi cally for internal carriage by Su-57 include the supersonic Kh-58UShK anti-radiation missile, long-range Kh-69 (here under its export designation Kh-59MK2) and Grom winged missile. They all fi t the Su-57’s weapon bays precisely