5th-Gen Fighter Aircrafts (in developement-testing)

Sukhoi PAK FA

The Sukhoi PAK FA (Russian: Сухой ПАК ФА, Russian: Перспективный авиационный комплекс фронтовой авиации, Perspektivny Aviatsionny Kompleks Frontovoy Aviatsii, literally "Prospective Airborne Complex of Frontline Aviation") is a twin-engine jet fighter being developed by Sukhoi for the Russian Air Force. The Sukhoi T-50 is the prototype for PAK FA. The PAK FA is one of only a handful of stealth jet programs worldwide.

The PAK FA, a fifth generation jet fighter, is intended to be the successor to the MiG-29 and Su-27 in the Russian inventory and serve as the basis of the Sukhoi/HAL FGFA being developed with India. The T-50 prototype performed its first flight 29 January 2010.

The Russian Defence Ministry will purchase the first 10 evaluation example aircraft after 2012 and then 60 production standard aircraft after 2016. The first batch of fighters will be delivered with current technology engines. The PAK-FA is expected to have a service life of about 30–35 years.

Overview

Video from the PAK FA's first flight shows that it has no conventional rudders; its vertical tails are fully movable. This special tail fin design is mechanically similar to V-tails used by the Northrop YF-23 in 1990s, but is supplemented by dedicated horizontal stabilators (as on the F-22). The T-50 has wing leading-edge devices above the jet engine intakes that may pose a challenge for signature control.Although most information about the PAK FA is classified, sources within in the Russian Air Force and Defense Ministry have openly stated that it features stealth technology and has the capability to supercruise, and incorporate advanced avionics such as anActive Electronically Scanned Array (AESA) radar and an artificial intelligence system. It is to be outfitted with the next generation of air-to-air, air-to-surface, and air-to-ship missiles.

Composites are used extensively on the T-50 and comprise 25% of its weight and almost 70% of the outer surface. It is estimated that titanium alloy content of the fuselage is 75%. Sukhoi's concern for minimizing radar cross-section (RCS) and drag is also shown by the provision of two tandem main weapons bays in the centre fuselage, between the engine nacelles. Each is estimated to be between 4.9-5.1 m long. The main bays are augmented by bulged, triangular-section bays at the wing root.The Moskovsky Komsomolets reported that the T-50 has been designed to be more maneuverable than the F-22 Raptor, at the cost of making it less stealthy than the F-22. One of the design elements that have such an effect is the Leading Edge Vortex Controller (LEVCON).

Stealth

Russian sources indicate the PAK FA lacks the very-low-observable (VLO) stealth of the F-22. Instead, reducing observability with composite materials, aerodynamic configuration, and engine signature reduction measures to achieve low (but not very-low) levels of radar, optic and infrared signatures. Carlo Kopp has said that once the PAK FA is fully developed into a stealthy design, it should be a rough match for the F-35 in low observability, but aerodynamically superior. Sources claim that the PAK FA may incorporate "Plasma stealth" although no solid evidence of this has been shown.

Armament

The PAK FA has a reported maximum weapons load of 7,500 kg. It has an apparent provision for a cannon (most likely GSh-301), and could possibly carry two 30 mm cannons. The PAK FA has two internal bays estimated at 4.6-4.7 metres by 1-1.1 metres. The expected initial armaments include Kh-35UE (AS-20 "Kayak"), Kh-38ME, Kh-58UShKE (AS-11 "Kilter"), and RVV-MD (AA-11 "Archer") missiles.

Two Izdeliye 810 Extended beyond visual range missiles per weapons bay. Multiple Izdeliye 180 / K77M beyond visual range missiles. K74 and K30 within visual range missiles can also be carried.Two KH38M or KH58 USHK air-to-ground missiles per weapons bay. Multiple 250–500 kg precision guided bombs per weapons bay, with a maximum of 10 bombs in internal bays. Other possible loads include one 1,500 kg bomb per weapons bay or two 400 km+ range anti-AWACS weapons (such as the RVV-BD) on external hardpoints.

PAK FA chief designer Alexander Davydenko has said that there is a possibility of the installation of BrahMos supersonic missile on the PAK FA and its FGFA derivative. However, it is unclear how these missiles will be installed, though it can be one or two missiles only due to heavy weight of the BrahMos.

Avionics

The PAK FA's SH121 radar complex includes three X-band AESA radars located at the front and sides of the aircraft. These will be accompanied by L-band radars on the wing leading edges. L-band radars are proven to have increased effectiveness against very low observable, or stealthy, targets which are optimized only against X-band frequencies, but their longer wavelengths reduce their resolution. However the initial prototypes will use legacy passive electronically scanned array radar. According to Sukhoi, the radar will reduce pilot load and make use of a new data link to share information between aircraft. In 2012 ground tests began on the third aircraft of the Tikhomirov Scientific Research Institute of Instrument Design's AESA radar.

The PAK FA will feature an OLS-50M infra-red search and track optical/IR search and tracking system. The OLS-50M is an upgrade to the previous OLS-35 infra-red search and track system due to advanced QWIP technology now being available. The OLS-50M will most likely have upgraded efficiency in identifying VLO (very low observability) aircraft at greater ranges.

Engines

On its first flights, the PAK FA was expected to use a pair of conventional Saturn 117S engines, but a new engine 117 (AL-41F1) powered its first flight. The new engine features a digital control system (FADEC), and is reportedly capable of producing 33,000 lbs (147 kN) of thrust in afterburner, has a dry weight of 1420 kilogram and a thrust to weight ratio of 10.5:1.

According to Sukhoi director Mikhail Pogosyan, the 117 (AL-41F1) is a new fifth generation engine built specifically for the PAK-FA. Pogosyan has clarified that claims of the use of an older engine are incorrect. Though the specifics of the new engine remain classified, information provided has included: increased engine thrust by 2.5 tonnes over the AL-31 engine, a reduction in engine weight by 150 kilograms (330 lb). These changes allow the aircraft to supercruise, sustaining supersonic flight speeds without using afterburners. Mikhail Pogosyan further mentioned that this engine (117) meets the Russian Air Force's requirements and will be installed in production PAK-FA aircraft.

The engine generates a larger thrust and has a complex automation system, to facilitate flight modes such as maneuverability. It is expected that each engine will be able to independently vector its thrust upwards, downward or side to side. Vectoring one engine up with the other one down can produce a twisting force, which would enable the PAK FA to be the first fifth generation fighter with full 3-D thrust vectoring along all three aircraft axes: pitch, yaw and roll. These engines will incorporate infrared and RCS reduction measures.

There is little information about the new engine of T-50. According to preliminary facts, the engine will have increased thrust and fuel efficiency as compared to AL-41F1. Allegedly, the powerplant will have a thrust of about 107 kN in cruise mode and 176 kN in full afterburner mode.

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: 29,772 kg (65,636 lb)
• Useful load: 7,500 kg (combat load) (16,534 lb)
• Max. takeoff weight: 37,000 kg (81,570 lb)
• Powerplant: 2 × AL-41F1 for prototypes turbofan, 147 kN (33,047 lb) for prototypes; over 175 kN (39,340 lbf) for definitive engine version each
• Fuel capability: 10,300 kg (22,711 lb)

Performance

• Maximum speed: Mach 2+, 2,100-2,600 km/h (1,300-1,560 mph) ; at 17,000 m (55774.3 ft) altitude
• Cruise speed: 1,300-1,800 km/h (808-1,118 mph)
• Ferry range: 5,500 km(3,417 mi)
• Service ceiling: 20,000 m (65,000 ft)
• Rate of climb: 350 m/s (68,900 ft/min)
• Wing loading: 330-470 kg/m² (67-96 lb/ft²)
• Thrust/weight: 1.01 (1.20 for new engines)
• Maximum g-load: 9+ g

Chengdu J-20

The Chengdu J-20 (Jian-20; simplified Chinese: 歼-二 十; traditional Chinese: 殲-二十; pinyin: Jiān èr shí) is a fifth-generation, stealth, twin-engine fighter aircraft prototype being developed by the Chengdu Aircraft Industry Group for the Chinese People's Liberation Army Air Force (PLAAF). The J-20 made its first flight on 11 January 2011.General He Weirong, Deputy Commander of the People's Liberation Army Air Force said in November 2009 that he expected the J-20 to be operational in 2017–2019.

The PLAAF designates the J-20 as "Project 718". The general designer of the aircraft is reportedly Yang Wei, who was the general designer of CAC/PAC JF-17 Thunder.

Characteristics

Song Wencong, the chief engineer of Chengdu Aircraft Industry, published a paper describing flight dynamics of the J-20.The paper cites high instability as an important design criteria in a fifth generation fighter. This necessitates good pitch-authority at high angle-of-attack, which cannot be provided by a tailplane due to its ineffectiveness at such flight profile. Hence, a decision was taken to employ a canard layout. An all-moving canard like the one on J-20 is capable of deflecting at the same magnitude but opposite sign to the angle-of-attack, thereby maintaining stability and control.The J-20 has a long and wide fuselage, with the chiseled nose section and a frameless canopy resembling the F-22 Raptor. Immediately behind the cockpit are low observable intakes mounted with a pair of upturned canards. They are followed by leading edge extension and a diamond wing. The aft section of J-20 features canted all-moving fins resembling those on F-35 and conventional round engine exhausts. An estimation using ground support vehicle as a reference shown the aircraft's length to be around 19 to 20 meters,slightly shorter than the length of a Flanker. In January 2013, a satellite picture taken over an airport at Xi'an showed J-20 to have similar length as a J-15/Su-33.

A canard delta offers greater efficiency in both subsonic and supersonic flight. Song Wencong's paper futher explains the combination of canard, leading-edge extension, and body lift for enhancing performance in a canard layout. According to a diagram attached to the paper, the J-20's configuration is able to generate 1.2 times the lift than an ordinary canard delta, and 1.8 times more lift than an aircraft that purely relies on wing for lift. This permits the use of small aspect-ratio wing, reducing supersonic drag without compromising transonic lift-to-drag characteristics that are crucial to the aircraft's turn performance. 

The J-20 may become the first operational combat aircraft that carries sufficient fuel to supercruise throughout its missions, doubling its sortie rate.

Engines

The prototype's engine is unknown, but is speculated to be either a AL-31 derivative or a version of the domestic WS-10. Western analysts believe that China is still working on a domestic turbofan engine to power the J-20 and will continue to use Russian engines for the aircraft for the time being.^[53] There have also been claims that China is seeking the AL-31 117S engine through Su-35 purchase. In response to such claims, China denied any deal of the Su-35. At the 2012 Zhuhai air show, Russia approached China with its 117S engine in an unsolicited yet unsuccessful attempt to sell Su-35.

The J-20's intended engine is speculated to be the WS-15, a turbofan engine producing 18 tons of thrust in development since the early 1990's. According to Global Security, the engine core, composed of high pressure compressors, the combustion chamber, and high pressure turbines were successfully tested in 2005. An image of the core appeared in the 2006 Zhuhai Airshow.

In late 2012, China announced a $50 billion investment program to catch up in the field of military turbofans. At the end of 2012, the Aviation Industry Corporation of China (AVIC) announced several breakthroughs in producing alloys for engine turbines, reaching standards used by leading global engine manufacturers.

Avionics

Official information on J-20's avionics is not publicly available. Examination of J-20 pictures revealed two small dark diamond shaped windows on both sides of the nose, which could house certain electro-optical sensors, such as a Missile Approach Warning System (MAWS) or an Infra-Red Search and Track (IRST) system. Windows similar to those in the Electro-Optical Distributed Aperture System (EODAS) onboard American F-35 can be found underneath the aft fuselage and on the fuselage above the canard. The J-20 is speculated to feature an advanced fly-by-wire (FBW) system that is integrated with the fire-control and the engine systems. China is known to have developed and deployed AESA radars on board its KJ-200 and KJ-2000 aircraft. In December 2012, new photographs emerged showing a J-20 prototype with a revised radome speculated to carry an AESA radar. As of January 2013, analysts expect the fire-control radar to be the Type 1475 or KLJ5 Active Electronically Scanned Array (AESA), roughly comparable in performance to the APG-77.

Cockpit

The aircraft features a pure glass cockpit, with two large color liquid crystal displays (LCD) situated side-by-side and three smaller ones in the surrounding. A wide-angle holographic head-up display (HUD) can be seen from close-up photos of J-20's cockpit. Many of these subsystems have been tested onboard J-10Bs to speed up the development.

Armament

The J-20 has a large belly weapon bay for short/long-range air-to-air missiles (AAM) (PL-10, PL-12C/D & PL-21) and two smaller lateral weapon bays behind the air inlets for short-range AAMs (PL-10).

One photo depicts the same air-to-air loadout as the F-22, that is six medium range and two short range air-to-air missiles.

In March 2013. A J-20 prototype is shown in a video armed with air to air missile similar to the F-22A. And in July 2013 a photo was released showing the hinged doors of the main bay open in flight.

Stealth

Analysts noted that J-20 uses similar stealth shaping design as the F-22 and F-35, providing good stealth capability at the front. However, these analysts also claimed the aircraft's side and axi-symmetric nozzles may expose the aircraft to radar detection. However, one of the prototypes uses WS-10G engines with stealthy jagged-edge nozzles and tiles.

Richard Aboulafia raised general doubts about the use of canards on a low-observable design, saying "there’s no better way of guaranteeing a radar reflection and compromise of stealth".However, canards and low-observability are not mutually exclusive design features. Northrop's proposal for the Naval Advanced Tactical Fighter (ATF), termed NATF-23, incorporated canard on a stealthy airframe. Lockheed Martin employed canards on a stealth airframe in the Joint Advanced Strike Technology (JAST) program. The Eurofighter managed to reduce its Radar Cross Section (RCS) by controlling the deflection of its canards through the flight control software.

The diverterless supersonic inlet (DSI) improves stealth performance by eliminating unwanted radar reflections between the traditional diverter and the aircraft's skin. As of January 2013, analysts have also noted that the J-20 DSI reduces the need for application of radar absorbent materials. Additionally, the "bump" surface reduces the engine fan's exposure to radar, significantly reducing the strongest radar reflection from a combat jet. While the diverterless supersonic inlet (DSI) intakes are easier to maintain than more complex stealth-compatible intakes, such as on the F-22, their fixed form limits the aircraft to around Mach 2.0.

The J-20 also features the use of a missile deployment device in its side-bays whereby the missile is extracted from the bay before the door is closed behind it. This essentially reduces the need for the doors to open mid-flight which would have exposed the fighter to an opposition radar temporarily, making this feature especially useful in a WVR environment where even the slightest increase in RCS may prove deadly.

General characteristics

• Crew: one (pilot)
• Length: 20.3 m (66 ft 7 in)
• Wingspan: 12.88 m (42 ft 3 in)
• Height: 4.45 m (14 ft 7 in)
• Wing area: 73 m² (790 sq ft)
• Empty weight: 17,000 kg (37,479 lb)
• Max takeoff weight: 36,287 kg (80,000 lb) upper estimate^[2]
• Powerplant: 2 × WS-10G (prototype); WS-15 in production J-20 afterburning turbofans dry, 180 kN (40,000 lbf) with afterburner
• Range: 4,000 km (2,485 mi; 2,160 nmi)
• Combat range: 2,000 km (1,243 mi; 1,080 nmi)
• Service ceiling: 20,000 m (65,617 ft)