The PAK FA (Russian: ПАК ФА, Russian: Перспективный авиационный комплекс фронтовой авиации, Perspektivny Aviatsionny Kompleks Frontovoy Aviatsii, literally "Prospective Airborne Complex of Frontline Aviation") is a fifth-generation fighter programme of the Russian Air Force being developed by Sukhoi of Russia. It will be used to meet the requirements of the Russian and Indian Air Forces. The first prototype aircraft, T-50, took its 47-minute maiden flight on 29 January 2010 at the Komsomol'sk-na-Amur Airport, and is planned for introduction in 2013. It is the first fighter aircraft developed by Sukhoi since the collapse of the Soviet Union.
The PAK FA when fully developed is intended to replace the MiG-29 Fulcrum and Su-27 Flanker in the Russian inventory and serve as the basis of the Sukhoi / HAL FGFA project being developed with India. A fifth generation jet fighter, it is designed to directly compete with Lockheed Martin's F-22 Raptor and F-35 Lightning II. The T-50 performed its first flight January 29, 2010. Its second flight was on February 6 and its third on February 12. As of June 17'th, it has made 16 flights in total.
The T-50 is the name of the prototype aircraft (though it is unlikely it will be the name for the production aircraft) designed by Sukhoi for the PAK FA programme. The aircraft is a stealthy, single-seat, twin-engine jet fighter, and will be the first operational aircraft in Russian service to use stealth technology. It is a multirole fighter designed for air superiority and attack roles. The fighter is planned to have supercruise, stealth, supermaneuverability, and advanced avionics to overcome the prior generation of fighter aircraft as well as ground and maritime defences.
In the late 1980s, the Soviet Union outlined a need for a next-generation aircraft to replace its MiG-29 and Su-27 in frontline service. Two projects were proposed to meet this need, the Sukhoi Su-47 and the Mikoyan Project 1.44. In 2002, Sukhoi was chosen to lead the design for the new combat aircraft, and in the summer of 2009 the design was approved. The PAK FA will incorporate technology from both the Su-47 and the MiG 1.44.
In September 2010, it was reported that India and Russia had agreed on a preliminary design contract where each country invests $6 billion; development of the FGFA fighter was expected to take 8–10 years.The agreement on the preliminary design was to be signed in December 2010.
T-50 prototype design
The Sukhoi T-50 is designed to perform supersonic flights at speeds of over 2,000km/h along with continuous in-flight refuelling. It will feature short take-off and landing capabilities, and can achieve greater agility, low radar visibility and low heat signature. The aircraft does not have rudders but its vertical tails are completely movable. The tail fin design is similar to the V-tails incorporated in the Northrop YF-23.
The horizontal stabilisers and wing-leading devices are principally used for signature control. The exterior part of the aircraft was designed using stealth or low-observable (LO) technology.
Design
Overview
The PAK FA is a fifth generation multirole fighter aircraft and the first operational stealth aircraft for the Russian Air Force. Although most information is classified, sources within the Sukhoi company and Defense Ministry have openly stated that the aircraft will be stealthy, supermaneuverable, have supercruise capability, incorporate substantial amounts of composite materials, and possess advanced avionics such as active phased array radar and sensor fusion.
The T-50 has a blended wing body fuselage and incorporates all-moving horizontal and vertical stabilizers; the vertical stabilizers toe inwards to serve as the aircraft's airbrake. The aircraft incorporates thrust vectoring and has adjustable leading edge vortex controllers (LEVCONs) designed to control vortices generated by the leading edge root extensions, and can provide trim and improve high angle of attack behaviour, including a quick stall recovery if the thrust vectoring system fails.The advanced flight control system and thrust vectoring nozzles make the aircraft departure resistant and highly maneuverable in both pitch and yaw, enabling the aircraft to perform very high angles of attack maneuvers such as the Pugachev's Cobra and the Bell maneuver, along with doing flat rotations with little altitude loss.The aircraft's high cruising speed and normal operating altitude is also expected to give it a significant kinematic advantage over prior generations of aircraft.
The T-50 makes extensive use of composites, comprising 25% of the structural weight and almost 70% of the outer surface.Weapons are housed in two tandem main weapons bays between the engine nacelles and smaller bulged, triangular-section bays near the wing root.Internal weapons carriage eliminates drag from external stores and enables higher performance compared to external carriage. Advanced engines and aerodynamics enable the T-50 to supercruise, sustained supersonic flight without using afterburners. Combined with a high fuel load, the T-50 has a supersonic range of over 1,500 km, more than twice that of the Su-27.In the T-50's design, Sukhoi addressed what it considered to be the F-22's limitations, such as its inability to use thrust vectoring to induce roll and yaw moments and a lack of space for weapons bays between the engines, and complications for stall recovery if thrust vectoring fails.
Stealth
The T-50 will be the first operational aircraft in Russian Air Force service to use stealth technology. Similar to other stealth fighters such as the F-22, the airframe incorporates planform edge alignment to reduce its radar cross-section (RCS); the leading and trailing edges of the wings and control surfaces and the serrated edges of skin panels are carefully aligned at several specific angles in order to reduce the number of directions the radar waves can be reflected.Weapons are carried internally in weapons bays within the airframe, and antennas are recessed from the surface of the skin to preserve the aircraft's stealthy shape. The IRST housing is turned backwards when not in use, and its rear is treated with radar-absorbent material (RAM) to reduce its radar return. To mask the significant RCS contribution of the engine face, the partial serpentine inlet obscures most, but not all, of the engine's fan and inlet guide-vanes (IGV). The production aircraft incorporates radar blockers similar in principle to those used on the F/A-18E/F in front of the engine fan to hide it from all angles. The aircraft uses RAM to absorb radar emissions and reduce their reflection back to the source, and the canopy is treated with a coating to minimize the radar return of the cockpit and pilot.
The T-50's design emphasizes frontal stealth, with RCS-reducing features most apparent in the forward hemisphere; the shaping of the aft fuselage is much less optimized for radar stealth compared to the F-22.The combined effect of airframe shape and RAM of the production aircraft is estimated to have reduced the aircraft's RCS to a value thirty times smaller than that of the Su-27.Sukhoi's patent of the T-50's stealth features cites an average RCS of the aircraft of approximately 0.1-1 square meters.However, like other stealth fighters, the T-50's low observability measures are chiefly effective against high frequency (between 3 and 30 GHz) radars, usually found on other aircraft. The effects of Rayleigh scattering and resonance mean that low-frequency radars, employed by weather radars and early-warning radars are more likely to detect the T-50 due to its physical size. However, such radars are also large, susceptible to clutter, and are less precise.
Engines
The PAK FA was expected to use a pair of Saturn 117S engines on its first flights. The 117S (AL-41F1A) is a major upgrade of the AL-31F based on the AL-41F intended to power the Su-35BM, producing 142 kN (32,000 lb) of thrust in afterburner and 86.3 kN (19,400 lb) dry. In fact, PAK FA already used a completely new engine in its first flight, as stated by NPO Saturn. The engine is not based on the Saturn 117S. The engine generates a larger thrust and has a complex automation system, to facilitate flight modes such as maneuverability. Exact specifications of the new engine are still secret. Each engine can independently vector its thrust upwards, downward or side to side. Vectoring one engine up with the other one down can produce a twisting force. Therefore the PAK FA will be the first fifth generation fighter with full 3-D thrust vectoring along all three aircraft axes: pitch, yaw and roll.
Avionics
The PAK-FA will have two X-Band AESA radars located on the front and back of the aircraft. These will be accompanied by L-Band radars which are thought to be located on the wing LERX sides, or on the wing leading edges. L-Band radars are proven to have increased effectiveness against VLO targets which are optimized only against X-Band frequencies, despite being less accurate.
The PAK-FA will feature an IRST optical/IR search and tracking system.
Sukhoi recently demonstrated cockpit mock-ups, which may relate to both Su-35 or PAK-FA, suggest two very large MFDs and a very wide HUD.
Hindustan Aeronautics Limited will provide the navigation system and the mission computer.
Cockpit
NSTsI-V helmet-mounted sight and display
The T-50 has a glass cockpit with two 38 cm (15 in) main multi-functional LCD displays similar to the arrangement of the Su-35S. Positioned around the cockpit are three smaller control panel displays. The cockpit has a wide-angle (30° by 22°) head-up display (HUD), and Moscow-based Geofizika-NV provides a new NSTsI-V helmet-mounted sight and display for the ZSh-10 helmet. Primary controls are the joystick and a pair of throttles.The aircraft uses a two-piece canopy, with the aft section sliding forward and locking into place. The canopy is treated with special coatings to increase the aircraft's stealth.
The T-50 employs the NPP Zvezda K-36D-5 ejection seat and the SOZhE-50 life support system, which comprises the anti-g and oxygen generating system. The 30 kg (66 lb) oxygen generating system will provide the pilot with unlimited oxygen supply.[98][99] The life support system will enable pilots to perform 9-g maneuvers for up to 30 seconds at a time, and the new VKK-17 partial pressure suit will allow safe ejection at altitudes of up to 23 km.
Armament
Armament incorporated on the Sukhoi PAK FA aircraft includes two 30mm internal cannon Gsh-30-1 guns and eight R-77 missiles. The aircraft features eight hard-points (four on each wing) on which the missiles are mounted.
The Gsh-301 is a single barrelled 30mm cannon manufactured by Izhmash JSC, Russia. The cannon can fire 1,500 to 1,800 rounds a minute and weighs around 64kg.
The R-77 missile is an air-to-air medium-range missile manufactured by Vympel, Russia. The missile weighs around 175kg.
Two large anti-ship bombs weighing 1,500kg each and two missiles developed by Novator Bureau are fitted in the aircraft.
The main bays can also accommodate air-to-ground missiles such as the Kh-38M, as well as multiple 250 kg (550 lb) KAB-250 or 500 kg (1,100 lb) KAB-500 precision guided bombs.The aircraft is also expected to carry further developed and modified variants of Kh-35UE (AS-20 "Kayak") anti-ship missile and Kh-58UShK (AS-11 "Kilter") anti-radiation missile.For missions that do not require stealth, the T-50 can carry stores on its six external hardpoints. PAK FA chief designer Alexander Davydenko has said that there is a possibility of the installation of BrahMos supersonic cruise missile on the PAK FA and its FGFA derivative; only one or two such missiles may be carried due to heavy weight of the BrahMos.
T-50 performance
The T-50 can climb at the rate of 350m/s. The maximum and cruise speed of the aircraft are 2,600km/h and 1,800km/h respectively. The range of the aircraft varies between 4,000km and 5,500km, and its service ceiling is 20,000m. The maximum endurance of the T-50 is three hours. The aircraft weighs around 18,500kg and has a maximum take-off weight of 37,000kg. The aircraft can hit targets within a 400km range.
General characteristics
* Crew: 1
* Length: 19.8 m (65.9 ft)
* Wingspan: 14 m (46.6 ft)
* Height: 6.05 m (19.8 ft)
* Wing area: 78.8 m2 (848.1 ft2)
* Empty weight: 18,500 kg (40,785 lb)
* Loaded weight: 26,000 kg (57,320 lb)
* Useful load: 7,500 kg (combat load) (16,534 lb)
* Max takeoff weight: 37,000 kg (81,570 lb)
* Powerplant: 2× New unnamed engine by NPO Saturn and FNPTS MMPP Salyut of 175 kN each. Prototype with AL-41F1 of 147 kN each,[49] definitive version with new engine >157 kN
* Maximum Fuel weight: 10,300 kg (22,711 lb
Performance
* Maximum speed: 2,600 km/h (Mach 2.45) (1,615 mph) ; at 17,000 m (45,000 ft) altitude
* Cruise speed: 1,300 - 1,800 km/h (808 - 1,118 mph)
* Ferry range: 5,500 km[50] ()
* Service ceiling: 20,000 m (65,616 ft)
* Rate of climb: 350 m/sec (1,148 ft/sec)
* Wing loading: 330(normal) - 470(maximum) kg/m2 (67(normal) - 96(maximum) lb/ft2)
* Thrust/weight: 1.4
* Maximum g-load: +11.0 g
