Imposter Or the Real Deal?

IMPOSTER OR THE REAL DEAL?

The Sukhoi Su-57 ‘Felon’ was originally conceived in an effort to compete against Lockheed Martin’s F-22 and F-35. Initially known as the PAK-FA, its development has progressed at a relatively slow pace — but has it matured as a force to be reckoned with? REPORT Alexander Mladenov

96 April 2020 // www.Key.Aero The Su-57’s overall conﬁ guration suggests that it has been designed to be stealthy in the forward hemisphere only, evidenced by well-exposed engines exhaust sections and nozzles. Vadim Savitskiy

HE RUSSIAN MILITARY is However, initial tactical evaluations bouncing back from years and instructor training with the Russian of underinvestment and Aerospace Forces (VKS) start this year, slow progress. The military on what is the largest and most complex supremacy enjoyed by development e ort ever undertaken America both numerically in the post-Soviet aerospace industry Tand technologically can no longer be in Russia. taken for granted. Russia’s ‘Flanker’ The Su-57 is also known as the series may be old, but few doubt the PAK-FA (Perspektivnyi Aviatsionnyi capabilities of its latest variants. The Su- Kompleks Frontovoi Aviatsii — Future 57 ‘Felon’ — its o cial NATO reporting Air Complex of Tactical Aviation). It name announced in October 2019 — is incorporates a signi cant level of Russia’s rst stealth ghter, and is an cutting-edge technology including interesting comparison with products stealthy characteristics, aerodynamics, from the West, which has been in the powerplant design, system integration ‘ fth-generation’ ghter game for more and weapons. Most of the aircraft’s than two decades. features are highly classi ed and there Known as the T-50-1, the rst of this new are more questions than answers when it generation of Russian ghter aircraft made comes to its true operational capabilities its maiden ight on January 29, 2010, in and performance. It is di cult to Komsomolsk-on-Amur, in the capable evaluate just how successful Sukhoi’s hands of Sukhoi’s chief test pilot Sergey world-class designers have been in Bogdan. It marked the beginning of the solving serious challenges posed by an comprehensive ight-testing e ort, which all-new high-performance stealth ghter remains in progress. The intervening design, combining extremely high agility years have seen a series of technological and maneuverability with supersonic and budgetary issues, but the project cruise (supercruise), advanced sensors, has steadily progressed. Signi cantly, the sensor fusion and robust multi-role so-called rst stage of joint state ight- mission capabilities. This ghter has testing was declared complete in July been conceived to meet a complex VKS 2017, an important step towards low-rate requirement that includes the ability to serial production. The second stage of undertake deep penetration missions this complex e ort, undertaken by the to knock out well-defended, high-value Russian military with support from Sukhoi, targets, and command the air in high- commenced in early 2018 and is ongoing. threat scenarios.

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The nozzles of the widely separated engines can be de ected in two planes, thereby providing e ective 3D thrust vectoring, with resultant control forces in pitch, roll and yaw axes — a design solution borrowed from the Su-30SM and Su-35 where the symmetric nozzle de ection is used for pitch control, while asymmetric de ection creates roll and yaw control forces. The 3D thrust-vectoring technology is considered to be a useful feature for retaining accurate control at slow speeds, when aerodynamic control surfaces are rendered ine ective. According to Sergey Bogdan, ight Evaluating the stealth It is also noteworthy that the Su-57’s performance is more or less similar to Sukhoi designers claim that the Su-57’s engines aren’t obscured by S-shaped inlet that of the Su-35. He reports a notable radar cross-section (RCS) is about 30 times ducts. The existing curvature appears di erence in supersonic acceleration smaller than that of a ‘Flanker’. Its fuselage insu cient to completely mask the engine — where he claims the Su-57 has no is distinctively angular and attened for compressors from incoming radar energy. equal. Bogdan has said that the Su-57’s RCS reduction, and there is extensive use However, the masking could be achieved acceleration is ‘raw and wild’. In addition, of radar-absorbing coatings plus enclosed by adding radar blockers in the inlets, Top: According he noted that the new ghter features weapons bays. but this aspect of the Su-57’s design still to Sukhoi, the good controlled spin characteristics, with Sukhoi designers aligned the leading remains highly classi ed. T-50-1 prototype rapid revolutions and a swift recovery. completed its edges of the wings, tailplanes and preliminary forward leading-edge extensions to Super maneuverability ground and ﬂ ight Supercruising capability make them parallel to each other. This all The Su-57 can perform ‘Flanker’ type trials campaign The ability to cruise in dry power and by early March points to a reasonably stealthy forward post-stall maneuvers, indicating a high 2011, with the lone supersonic speed (supercruise) is hemisphere that o ers tactical advantages level of agility for close-in ghting. prototype having considered vital in modern ghter design in head-on air-to-air and air-to-surface Its blended-body aerodynamic amassed 36 and this is achieved in the Su-57 via sorties. Sukhoi engagements. However, there is little con guration features a lift-generating two principal design features. For the evidence of RCS reduction measures in body, fuselage extensions for improving Above left: The ‘Felon’ it’s a combination of low drag for the rear hemisphere, with well-exposed aerodynamic performance at high angles Su-57’s K-36D-5 a high lift-to-drag ratio in supersonic ejection seat engine nozzles. In fact, this approach is of attack and wings liberally endowed is the same as cruise, combined with a high thrust-to- likely attributed to the Russian concept with high-lift devices. There are no fewer that used on the weight ratio. The Su-57’s wide engine for low observable design — there’s little than 12 ight-control surfaces, grouped Su-35, featuring installation accommodates rather large so-called ‘smart inclination to trade overall performance in six symmetrical pairs, augmented control’ of the and deep weapons bays, a ording a with RCS reduction. Instead, Sukhoi has by moving engine nozzles for thrust ejection sequence ‘clean’ con guration in all mission modes, tended to rely on the use of an advanced vectoring control. The six pairs of to increase the with increased-thrust engines and a chances of multi-spectral sensor suite. This approach aerodynamic surfaces include all-moving pilot survival lightweight airframe using composite was conceived to a ord better detection horizontal stabilizers, all-moving vertical in complex materials. The aircraft can optionally carry capability to counter the potential tails, ailerons, wing leading-edge aps, situations such as external stores if required. low-level inverted advantage of other low-observable (LO) aperons and wing moving leading-edge ﬂ ight. Alexander The Su-57, in its initial con guration, platforms such as the F-22. extensions. Mladenov is powered by a pair of AL-41F-1

98 April 2020 // www.Key.Aero active electronic scanning array (AESA) radar. This is augmented by a second module, also working in the X-band, which employs a pair of side-looking antennas just aft of the nose antenna, designed to expand the system’s angular coverage in azimuth. The third element is a pair of L-band phased-array antennas built into the wing leading-edge extensions, intended to endow the Su-57 with enhanced detection performance against stealth aircraft, as well as for identification friend or foe (IFF) purposes. Stealth technologies fielded in Western fighters are mostly tailored to counter airborne and ground-based radars operating in the X-band; as a consequence, LO characteristics are afterburning turbofans — an evolution supersonic and subsonic regimes of flight, deemed less effective when pitted against of the AL-31 series of engines powering Above: The T-50-3 hitting Mach 2.0 and above. L-band airborne radars. This could be also prototype is being the Su-27/30 family, developed by NPO used for manned- regarded as an attempt to compensate Saturn-Lyul’ka and designated as the unmanned Sensor fusion for the Su-57’s apparently higher RCS so-called ‘Phase 1’ powerplant. Its design teaming trials The Su-57 features the brand new NIIP compared with that of the F-22 and F-35, with the S-70 is based on the izdeliye 117S engine of the Okhotnik Tikhomirov N036 Byelka modular multi- which would facilitate extended-range Su-35, with a dry rating of 20,938lb (93kN) (‘Hunter’) band radar system, also known as Sh121. detection of these fighters. thrust while the full afterburner rating is jet-powered This integrates three principal modules The infrared search-and-track (IRST) stealth-design 33,060lb (147kN) thrust. unmanned aerial — one being the nose-mounted X-band sensor suite is integrated with the Su-57’s The definitive Su-57 engine, dubbed vehicle. Alexander izdeliye 30, began flight-testing in Mladenov December 2017 on the T-50-2 prototype. Right: The This is the so-called ‘Phase 2 engine’, with T-50-1 prototype full-authority digital control, expected to approaching the factory airfield be rated at about 24,220lb (107kN) dry and in Komsomolsk- 37,468lb (166.77kN) at full afterburner. The on-Amur on new engine — expected to be installed completion of its maiden flight on on production-standard Su-57s by 2022 at January 29, 2010, the earliest — is lighter, more powerful and in the capable includes a reduced number of components. hands of Sukhoi’s chief test pilot, In addition, the Su-57 uses variable-area Sergey Bogdan. intakes for optimum performance in both Sukhoi

Sukhoi’s chief test pilot Sergey Bogdan completed a demonstration of a short landing roll with early opening of the twin brake parachutes at the MAKS 2019 airshow, in front of Vladimir Putin. Alexander Mladenov

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weapons control system, and it includes medium-range active radar-guided Above clockwise: capable of delivering heavy warloads of the 101KS-V targeting system installed missiles (also known as the RVV-SD) for T-50-9 carrying up to 11,000lb (5,000kg). In March and a camera pod in the nose as well as 101KS-U ultraviolet beyond-visual-range engagements, designed to record April 2016, the T-50-2 prototype was missile approach warning sensors under while two short-range K-74M2s (RVV-SD) missile launches spotted involved in aerodynamic flight the nose and built into the rear fuselage, are accommodated in side bays in the during testing. trials carrying six distinctly old-fashioned Vadim Savitskiy along with an 101KS-O electro-optical underwing fairings. In 2018, it was further OFAB-250-270 freefall fragmentation/ jammer. A navigation/targeting pod, revealed that the ‘Felon’ can also use the The UOMZ 101KS-N high-explosive ‘dumb’ bombs. navigation/ dubbed 101KS-N, can also be carried in K-37M (RVV-BD) long-range air-to-air targeting pod It also features the proven 30mm GSh- uncontested strike missions when stealth missile, capable of engaging targets at is designed to 30-1 single-barrel cannon as used on the performance is not required. up to 110nm (200km) distance in head- be carried on Su-27/35 and MiG-29, albeit in a vastly strike missions The Su-57 also features the L402 Gimalay on attacks. The tandem internal bays when stealth improved version dubbed the 9-A1-4071K. integrated electronic warfare (EW) system, between the engines can also house large- is not required. It is installed starboard, with the barrel but no specific information has been size air-to-surface and anti-ship missiles as Alexander protruding adjacent to the cockpit, and is Mladenov released yet about its components and well as large guided bombs. provided with 150 rounds. The antenna real operational capabilities. When stealth is not required, the Su-57 The air-to-surface precision-guided array of the can carry missiles and bombs on at NIIP Tikhomirov arsenal includes the newly developed Kh- Weapons for all occasions least four underwing pylons plus two N036 radar, 38 modular missile that uses a variety of also known as The Su-57 features centerline weapons more under the engine trunks. In these guidance packages, plus the Kh-58UShK Sh121. Alexander bays capable of housing up to four K-77M missions the aircraft is advertised as being Mladenov long-range anti-radar missile optimized

100 April 2020 // www.Key.Aero A DOOMED INDIAN PARTNERSHIP The PAK-FA was set to be used as a basis for the development of an international T-50 version, undertaken in partnership with India. An intergovernmental agreement on the international version was formalized in 2007. Then a tripartite contract, inked in December 2010 by Sukhoi, Hindustan Aeronautics Limited (HAL) and Russia’s arms export monopolist Rosoboronexport, it covered a preliminary development e ort for an advanced multi-role fth- generation ghter, designated by India as the Fifth Generation Fighter Aircraft (FGFA). The program was valued at $295 million and set at 18 months. It was initially expected that the eventual number of FGFAs ordered for internal carriage (with maximum range the Tactical Missiles Corporation showed Above: The for India would reach between of 132nm [245km]) and two new versions to the public two brand new guided Su-57 uses a 250 and 300 aircraft — with a of the Mach-3 Kh-31 missile. The Kh-31AD, bomb types with satellite/INS guidance blended-body potential purse of $25 billion. The aerodynamic FGFA development e ort was intended for use against ships, is out tted packages, which can be carried by the confi guration, with an active radar seeker and has a Su-57. The rst of these is the K08BE, including a lift- originally planned for completion by 2016 or 2017, while induction maximum range of 86nm (160km), while weighing 1,113lb (504kg) and the second generating body, complemented into Indian Air Force (IAF) service the Kh-31PD is designed for knocking one is the K029BE, weighing 3,361lb by fuselage was to take place by 2020. In fact, out radars, with a passive radar seeker (1,525kg). Boris Obnosov, director general extensions and the ambitious program began and maximum range quoted as 135nm at the Tactical Missiles Corporation, hinted high-lift leading- stagnating during 2012, with edge fl aps on (250km). The Kh-35U is another anti-ship in August 2018 that his company could little progress and never-ending the wing. Vadim negotiations between the partners Savitskiy missile touted for the Su-57, with range of start developing new-generation guided for more than ve years. The Indian up to 140nm (260km). bombs weighing 220lb (100kg) and Below: The fourth side expressed a requirement to There is also a range of guided bombs possibly 110lb (50kg) for the ‘Felon’. fl ying prototype, participate in aircraft testing as well with laser, TV and satellite guidance The Su-57 is also set to use new- T-50-4, took as in the development of certain systems set to be incorporated into the Su- generation, special-purpose unguided to the air in systems, in a bid to raise the level December 2012. of its technology competence not 57, such as the 550lb (250kg) KAB-250 and bombs such as the 1,100lb (500kg) Sukhoi forthcoming in a straight purchase. the 3,306lb (1,500kg) KAB-1500. In 2019, OFZAB-350 (out tted with a high- By 2014, high-ranking Indian military representatives were expressing dissatisfaction with the engine performance and low– observability characteristics of the Sukhoi designers claim that the T-50 as well as with the weapons and the project timeframe. In February 2016, it was revealed Su-57’s radar cross-section is about that Russia and India had at last reached a general agreement on 30 times smaller than that of a ‘Flanker’ a signi cant cost reduction for the FGFA program. However, in April 2018, the Indian government was considering its withdrawal from the FGFA program, while sources in Moscow still preferred to remain silent. In August that year, Dmitry Shugaev, the head of Russia’s federal service of military-technical co-operation — the country’s arms export control body — publicly acknowledged that the FGFA project had been shelved. No further news has been forthcoming and the plan appears to have been completely abandoned.

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explosive/fragmentation/incendiary test ights in Komsomolsk-on-Amur, it warhead) and the ODAB-500PMV with a was transported by air to Sukhoi’s main Above: The infrared search- thermobaric warhead. test base in Zhukovsky, near Moscow, on and-track (IRST) is integrated with the Su-57’s weapons December 28, 2011, to continue system control system, as are Flight-test progress testing and evaluation. T-50-3 was the rst ultraviolet missile approach According to Sukhoi, preliminary ground example to be equipped with N036 AESA warning sensors under the nose and rear fuselage, along and ight trials were completed in early radar in addition to a pair of 101KS-U IRST with an electro-optical jammer. March 2011 using the T-50-1 prototype, sensors under the nose and on the tail Vadim Savitskiy which amassed 36 sorties. This included boom; it also sported three UV-50 cha / Right: This is the ill-fated evaluation of stability and controllability are dispensers built into the rear fuselage. T-50S-1, the fi rst production- performance as well as some other The fourth ying prototype, T-50-4, took standard ‘Felon’ for the VKS, important characteristics while expanding to the air in December 2012, while the lost in its fi rst post-assembly test fl ight on December 24, the speed, altitude and g-load limits. fth, T-50-5, followed in October 2013. 2019. The fi ghter, seen here in The second ying prototype, T-50-2, These aircraft were used for avionics fi nal assembly at the KnAAZ took to the air for the rst time in March and sensor testing, out tted with many plant, was included in the order for two production-standard 2011, while the third one, T-50-3, followed components of the integrated avionics Su-57s, placed in August 2018. in November and, after a series of initial suite otherwise lacking in T-50-1/2. Via Russian internet

102 April 2020 // www.Key.Aero Sukhoi’s former chief, Mikhail Pogosyan, The aircraft hit the ground some 60nm said the initial e ort was designed to (111km) north of Komsomolsk-on-Amur, achieve preliminary approval from the with factory test pilot Alexey Gorshkov Russian military authorities to con rm the ejecting safely. ghter performed as expected, allowing The sharp cut in initial procurement was COMBAT for the test e ort to proceed into the next most likely caused by the unsatisfactory stage — joint state-testing, undertaken ight performance exhibited by the early TESTING jointly with the air force at its 929th State aircraft. Instead, the Russian military Fight-Test Center in Akhtubinsk. decided to wait for the introduction IN SYRIA It is here that serious technical issues of the more powerful ‘second- On May 25, 2018, the Russian minister were encountered. The most serious was stage’ engines. of defense Sergey Shoygu disclosed with T-50-5, which sustained extensive Unexpectedly, a large Su-57 order came the nature of the testing undertaken damage in a re immediately after landing in June 2019, mainly due to Russian by the Su-57 in operations in Syria. at Zhukovsky on June 10, 2014. This President Vladimir Putin’s personal He said that during a three-day spell at Khmeimim air base in Syria, two aircraft was subsequently rebuilt using intervention. He said the large ‘Felon’ Su-57s were valuated in a combat the fuselage originally constructed for the order had become possible thanks to a environment. The sketchy brie ng T-10-6. Receiving the new designation signi cantly reduced unit price, promised was accompanied by a brief video T-10-5R, the fth prototype returned to by United Aircraft Corporation (UAC), the showing a T-50 prototype launching the air in its new guise in October 2015. parent company of Sukhoi. According a cruise missile, but there was no con rmation that this speci c footage T-10-6 was then completed with new to the Russian daily newspaper originated from the Syrian campaign. components. As a result it was signi cantly Kommersant, the order for 76 Su-57s The Su-57’s much-touted delayed and didn’t y for the rst time was valued at about $2.8 billion, with all deployment to Syria between until the end of April 2016, while T-50-8 aircraft to be delivered by 2028. February 21-23, 2018, involved followed in November the same year. These Su-57s, to be powered with prototypes T-50-9 and T-50-11, operated by the 929th State Flight- Overall, 2017 was a productive year for a mixture of AL-41F-1 and izdeliye 30 Test Center at Akhtubinsk. The two the program, with T-50-9 own in April engines, are deemed to be su cient for prototypes were accompanied by 2017, followed by T-50-11, which ew equipping three ghter regiments, each ying laboratories, which monitored in August that year. The last prototype elding 24 aircraft in two squadrons. weapons events. Footage released for state testing — T-50-10 — ew at Four more examples are to be taken on by the Russian ministry of defense showed a Su-57 launching a test Komsomolsk-on-Amur in December strength by the combat training center round appearing to be a new Raduga 2017. It is noteworthy that the T-50-10 in Lipetsk, to be used for conversion Kh-59MK2 long-range air-to-surface was delivered in a con guration said to be training and tactics development work. missile. production-standard. This large indigenous order is a major In December 2019, the Russian In 2018, the Su-57’s development and shot-in-the-arm for the Su-57. Despite chief of the general sta of the armed forces, Gen Valeriy Gerasimov testing e ort continued at pace. According a decade of test and development divulged that Su-57 prototypes to Russian industry and trade minister, work, the aircraft still has a long way underwent a second combat testing Denis Manturov, who spoke to reporters to go to achieve its full potential, but campaign in Syria in 2019. in January that year, ight-testing of the Putin realized the procrastination of the de nitive Su-57 version — powered by Russian ministry of defense couldn’t the new izdeliye 30 engines ( own for the continue. To make meaningful progress, a stream of upgrades and re nements rst time on T-50-2 on December 5, 2017) the VKS needed to get behind its new as the VKS builds corporate knowledge — was set for completion in three years. stealth ghter in order to develop of the ‘Felon’, so that it can start down By December 2019, the new engine was greater operational understanding and the path of building operational reported to have completed 16 ights on experience. This will likely combine with credibility. the T-50-2. VKS begins Su-57 purchases As a result of the various testing delays, the number of production-standard aircraft ordered under Russia’s State Armaments Program 2020 was to be reduced from 52 to just 12 aircraft. This gure was deemed su cient to equip one instructor/research squadron at Lipetsk. This initial order was further reduced to two aircraft, and eventually placed in August 2018, with deliveries slated for late 2019 and early 2020. In fact, the rst of these aircraft, known as the T-50S-1 (c/n 51001), was lost during a factory test ight on December 24, 2019, due to a ight control system failure.