SUKHOI Su-57 MILITARY

A new designation has been assigned to ’s first fifth- Enter the generation fighter developed under the Perspektivnyi Aviatsionnyi Kompleks Frontovoi Aviatsii programme. Piotr Butowski reports from MAKS 2017 in Zhukovsky

Su-57ussian president Vladimir Putin was SU-57 FINAL SENSOR SUITE CONFIGURATION expected to visit a specially erected hangar during the opening ceremony on the first day of this year’s MAKS 2017 air show. In front of the latest PAK FA prototype, T-50-9, in Putin’s presence, the Rpreliminary conclusion on the first stage of T-50 testing and a recommendation to produce an initial batch of the fighters was to be signed. In addition to the planned signing, the T-50 was due to be officially designated the Su-57. Neither event • N036 forward-looking X-band radar antenna is an oval about 900mm (35in) long and 700mm (28in) happened. Due to lack of time Putin did wide; the array’s sheet comprises 1,552 transceiver modules; its reflector is tilted upwards by about 15° not visit the hangar. The documents on • N036B side-looking X-band arrays consist of 358 transceiver modules each; the lateral arrays are used testing and initial production were signed for widening the angle of search and tracking targets in azimuth up to +/-135° from the aircraft’s axis two days later, and the new designation • N036L L-band arrays mounted in the wing leading edges are used for friend-or-foe identification and was officially announced by the Russian Air for the detection of aerial targets Force Commander-in-Chief Viktor Bondarev • 101KS-V (Vozdukh/Air) infrared search and track sensor fitted in front of the pilot’s cockpit on August 11. • 101KS-U/01 (U for ultraviolet) is a side-looking ultraviolet missile approach warning sensor (MAWS); Choice of Su-57 as the official two are mounted on the fuselage sides, just aft of the cockpit • 101KS-U/02 sensors are shaped like a house with two windows, one looking forward and the other to designation of the T-50 PAK FA is because the rear; one such sensor is mounted under the forward fuselage, and the other on the upper surface of it is the latest in a series of gradually the fuselage improved long-range air-superiority fighters. • 101KS-O sensors, one on the fighter’s spine and another under the nose; the purpose of these The Su-27, the first in the series, appeared sensors remains unclear in 1982 and is the backbone of the Russian • 101KS-P (Posadka/Landing) device comprises a small imaging infrared sensor to aid low-level flying Air Force’s fighter fleet. The Su-37 was an and landing; it is fitted in the forward section of the canoe-shaped underwing missile bay experimental aircraft, originally built as a • 101KS-N (Nazemnyi/Ground) is a navigation and targeting pod; typically in this class of system, the Su-27M with side number 711; it appeared 101KS-N contains a stabilised platform with electro-optical and 3-5μm thermal imaging cameras (they in 1994 fitted with thrust-vectoring engines. use a common optical package, including the scanning mirror and automatic tracking unit), a laser rangefinder/target indicator and laser spot tracker The Su-47 Berkut was another experimental • L402 ECM system has its own array in a large sting between the engine exhaust nozzles and utilises fighter from 1997 and Sukhoi’s first attempt the N036 arrays as well at building a new-generation fighter featuring a forward-swept wing. Prototypes and problems T-50-9, 509, on April 24, 2017. There were 30 Two T-50s performed synchronised aerobatics months between the debut of the sixth aircraft, SU-57 ESTIMATED and a simulated aerial combat during MAKS T-50-6-2 and the preceding machine, T-50-5 CHARACTERISTICS 2017. As in previous years, the public and (first flight on October 27, 2013). Significant press were kept away from the aircraft. design changes were introduced in the interim, Wingspan: 14.1m (46ft 3in) (first prototypes 14.0m, 45ft 11in) Problems revealed in tests of the initial (T-50-7 is a non-flying static test airframe). prototypes have resulted in upgrades to the The three newest examples differ from the Length: 20.1m (66ft) (first prototypes 19.7m, airframe since the type’s last appearance at previous five aircraft by having a stronger inner 64ft 7in) MAKS two years ago. Initial production batches airframe structure. Part of the aircraft’s metal Height: 4.6m (15ft 1in) will comprise aircraft finished to the current skin has been replaced with composites. The Empty weight: 18,000kg (39,683lb) standard. However, work continues to improve aft fuselage section (housing electronic warfare Nominal take-off weight: 25,000kg (55,116lb) the specification of the fighter, including equipment) is longer, the circumference of the the installation of new engines and mission aft lower fuselage, some doors and hatches, Max take-off weight: 35,000kg (77,162lb) systems. as well as wingtips have all been modified. Max speed: Mach 2.0 The addition of three further T-50 flying The wingspan has been increased from 14.0m Supersonic cruising speed: Mach 1.3 prototypes has increased the fleet of aircraft (45ft 11in) to 14.1m (46ft 3in), and the fuselage in the test programme since MAKS 2015 to length from 19.7m (64ft 7in) to 20.1m (66ft); Max supersonic range: 810nm (1,500km) eight. The sixth aircraft T-50-6-2, 056, made these are estimated data. Max range: 1,890nm (3,500km) its maiden flight on April 27, 2016, followed The design changes were caused by by T-50-8, 058, on November 17, 2016, and problems that included structural cracks

25 MILITARY SUKHOI Su-57

T-50-9 509 was supposed to be shown to Vladimir Putin in a separate, closed pavilion, painted in similar large pixels. The type’s new Su-57 designation was supposed to be officially announced there, but the ceremony did not take place.

suffered by the early T-50 prototypes during compressor stall of the starboard engine during 16, 2015. testing. T-50-1 was taken out of the flying its take-off roll; a flame several metres long As well as the industry test centre in schedule for overhaul for over a year between shot out of the exhaust nozzle and the pilot Zhukovsky, since February 2014 the T-50 August 2011 and September 2012 after abandoned his take-off. Embarrassingly the prototypes have been under evaluation by structural damage caused during a display fifth aircraft, T-50-5, caught fire on the runway military pilots at the MoD’s test centre at at MAKS 2011. The airframe now carries after landing during a presentation for an Indian Akhtubinsk. Vladimir Mikhailov, the former various external signs of strengthening. Engine delegation on June 10, 2014. Its subsequent commander-in-chief of the , problems have resulted in several single- overhaul at Komsomolsk-on-Amur lasted 16 told Russian television in March 2016 that the engine emergency landings. MAKS 2011 was months. It is now designated T-50-5R and T-50 had launched a weapon from its internal a bad time for the type, with T-50-2 suffering a resumed flight tests after the repair on October armament compartment for the first time.

T-50-2 landing at Zhukovsky showing some of the modifications made to the aircraft during the first stage of testing. The main undercarriage doors are re-shaped and the fairing of the electronic countermeasures antenna located between the engines nozzles is new.

26 SUKHOI Su-57 MILITARY

Final sensor suite configuration The latest aircraft, T-50-9, is the first to have a sensor suite like production versions of the Su- 57. Previous prototypes had only partial suites and/or structural mock-ups of the sensors. All the Su-57’s systems and sensors are coupled and controlled by a central computer. The Sukhoi Design Bureau is responsible for systems integration, which is a novelty. In the past, fire-control and flight navigation systems were integrated by instrument manufacturers. On Sukhoi fighters, this work was usually entrusted to RPKB of Ramenskoye. The sensor suite includes the Sh121 radio-electronic system and 101KS electro-optical system. The Sh121 suite developed by the Tikhomirov NIIP institute in Zhukovsky comprises the N036 radar and the L402 electronic intelligence and electronic countermeasures (ECM) suite. The NIIP N036 Byelka (squirrel) radar has five active electronically scanned arrays, three X-band (37.5 to 25mm wavelength) and two L-band (300 to 150mm wavelength), that together control the airspace within the angle up to 270° (+/-135° from the aircraft’s axis). Use of L-band radar in air-to-air mode is the T-50’s main means of dealing with stealth targets, which may be detected (but not targeted) by radio waves longer than the X-band for which the radar cross-section’s reduction is typically optimised. According to the head of NIIP Yuri Belyi, the N036 radar installed on T-50-9 was Sergey Bogdan and Sergey Chernyshev flew a demonstration which included aerobatics and an air-to-air the last one to be made by the experimental engagement. The demonstration was notable though not that dynamic due to flight envelope restrictions. production facility of NIIP’s design bureau at Both aircraft, T-50-2 and T-50-4, are prototypes built without the current upgrade. Zhukovsky; subsequent aircraft will be fitted with radars made by the GRPZ production According to a press release published by PAK FA 2.0 facility of Ryazan. Sukhoi for MAKS 2017 currently: “. . . the According to the aforementioned Sukhoi press The L402 Gimalai (Himalaya) ECM suite first stage of state trials is nearing its end . . . release, the PAK FA “will be the company’s developed by the KNIRTI institute in Zhukov Characteristics of stability and controllability primary product on the market of aircraft near Kaluga and manufactured by the Signal at subsonic and supersonic speed, at technology starting from 2020”. By this time factory in Stavropol is provided with its own low and high flight altitudes, as well as on an upgraded jet, the so-called second stage aerials, but when working within the same supercritical angles of attack are confirmed.” PAK FA is planned to be available. The updated range of frequencies used by the radar it The first stage of state trials is in fact not a version will feature new izdeliye 30 engines; the utilises the N036’s arrays. very advanced level of testing; it concludes current AL-41F-1 engines (izdeliye 117) are in The 101KS Atoll electro-optical suite with the acceptance of the aircraft as a flying fact upgraded AL-31 engines as fitted to the produced by UOMZ in Yekaterinburg is vehicle. Only the completion of the second Su-27. intended to provide full control of the space stage, when mission systems and armament An interesting presentation by the United around the aircraft in the optical range, as well are tested, allows the aircraft to be officially Engine Corporation from 2013 shows as self-defence against missile attack. The Atoll entered on the air force’s inventory. production plans as they were then: 150 includes the forward-looking 101KS-V infrared Russia expects to buy fewer Su-57s than izdeliye 117 and 340 izdeliye 30 engines to be search-and-track (IRST) sight, four ultraviolet previously planned. On March 23, 2015, deputy built before 2025. That means production of missile approach warning sensors (MAWS) minister of defence Yuri Borisov visited the plant the first-stage T-50 was not planned beyond that cover the whole sphere around the fighter, at Komsomolsk-on-Amur and said that the air the initial 60 aircraft (currently reduced to 12); as well as two 101KS-O sensors that UOMZ force might buy fewer T-50s than planned in the remaining 30 engines are just enough says are directional infrared countermeasures. the National Armament Programme for 2020 for prototypes and other trials. The other Another 101KS-P device comprises a small (GPV-2020), buying instead lower-cost Su-30s number, 340 izdeliye 30s, is interesting. imaging IR sensor to aid low-level flying and and Su-35s. Russian media quoted a source Deducting, some engines for tests, suggests landing. The related 101KS-N navigation and within the Russian MoD who stated the air force that production of 150-160 second-stage T-50 targeting pod is under development for the will order only one squadron by 2020 (Russian fighters during 2020-2025 was planned. Now Su-57. fighter squadrons have 12 aircraft), instead of the plans are undoubtedly being downsized. the 60 aircraft promised by GPV-2020. The first demonstrator of the izdeliye 30 Shrinking production plans One reason for the reduction in planned engine ran in a ground testbed on November In the official ‘Schedule of activity of Russia’s Su-57 production is internal competition 11, 2016. It is still claimed that flight trials of the Ministry of Defence for 2013-2020’ published by from the latest versions of fourth-generation engine will begin in 2017. the MoD in 2013, the PAK FA’s initial operating fighters, particularly the Su-35. Apart from The izdeliye 30 is a clean-sheet design capability and the launch of full-scale series the Su-57s stealth qualities, there is little to intended to offer increased thrust of 16–17 production were scheduled for December choose between the two and the Su-35 is tonnes compared to 14.5 tonnes today, to 31, 2016. This deadline was not met and the constantly being improved. After Borisov’s be lighter, and have fewer parts and lower document itself is no longer mentioned by visit to Komsomolsk-on-Amur, the Russian operating costs. Stealth features are to be anyone. The president of UAC, Yuri Slyusar, Ministry of Defence, which has already ordered introduced. The engine’s cold section will said days before MAKS that three more T-50 98 Su-35S and 116 Su-30SM fighters, issued have a three-stage compressor (instead prototypes would have to be built for the an official statement about reduction in the of four as in the current 117 engine) and a contracted research and development work and number of PAK FAs to be ordered. Added to it single-stage turbine; the hot section (engine the Komsomolsk-on-Amur plant will commence was the observation that “the Su-35 fighters of core) will have a five-stage compressor deliveries of the initial batch of production- the so-called fourth-plus generation show good (instead of a nine-stage one) and a single- standard fighters in 2019. characteristics in the opinion of military pilots”. stage turbine.

27 MILITARY SUKHOI Su-57

After successful completion of the first stage of T-50 testing, a preliminary conclusion of the test programme was signed at MAKS 2017. The state commission recommended production of an initial batch of aircraft which are to be assigned the new Su-57 designation. All photos Piotr Butowski

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