Chengdu J-20

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J-20
J-20 2011.jpg
Role Stealth air superiority fighter / multirole combat aircraft
National origin China
Manufacturer Chengdu Aircraft Industry Group
Designer Chengdu Aircraft Design Institute
First flight 11 January 2011[1][2]
Introduction 2018 (planned)[2]
Status In development / flight testing[2]
Primary user People's Liberation Army Air Force
Number built 6 prototypes[3][4]

The Chengdu J-20 (simplified Chinese: 歼-20; traditional Chinese: 殲-20) is a Stealth, twin-engine fifth-generation fighter aircraft prototype being developed by Chengdu Aircraft Industry Group for the Chinese People's Liberation Army Air Force (PLAAF).[5] The J-20 made its first flight on 11 January 2011,[1][2] and is expected to be operational in 2018.[6][7]

China's J-20 platform has the potential to be a capable, long-range strike system in the Asia-Pacific region, but a number of technical challenges will need to be overcome before production can begin.[8]

Development[edit]

Origins[edit]

Origins of the J-20 came from the J-XX program which was started in the late 1990s. A proposal from Chengdu Aircraft Industry Group, designated "Project 718", had won the PLAAF endorsement following a 2008 competition against a Shenyang proposal that was reportedly even larger than the J-20.[9]

In 2009, a senior PLAAF official revealed that the first flight of the new fighter was expected in 2010–2011, with an entry into service scheduled for 2019.[10]

On 22 December 2010, the first J-20 prototype underwent high speed taxiing tests outside the Chengdu Aircraft Design Institute.[11][12]

Flight testing[edit]

On 11 January 2011, the J-20 made its first flight, lasting about 15 minutes, with a Chengdu J-10S serving as the chase aircraft.[13][14] After the successful flight, a ceremony was held, attended by the pilot, Li Gang, Chief Designer Yang Wei and General Li Andong (Deputy-Director of General Armaments).[15]

Artist impression of The Chengdu J-20 aircraft prototype

On 17 April 2011, a second test flight of an hour and 20 minutes took place.[16] On 5 May 2011, a 55-minute test flight was held that included retraction of the landing gear.[17]

On 26 February 2012, a J-20 performed various low-altitude maneuvers.[18] On 10 May 2012, a second prototype underwent high speed taxiing tests, and flight testing that began later that month.[19][20] On 20 October 2012, photographs of a new prototype emerged, featuring a different radome, which was speculated to house an AESA radar.

On March 2013, images of the side weapon bays appeared, including a missile launch rail.[21][22][23]

On 16 January 2014, a J-20 prototype was revealed, showing a new intake and stealth coating, as well as redesigned vertical stabilizers, and a system that appeared to be an Electro-Optical Targeting System.[24][25][26] This particular aircraft numbered '2011' performed its maiden flight on 1 March 2014 and is said to represent the initial pre-serial standard. Overall the year 2014 was quite a successful one and until the end of 2014 three more pre-serial prototypes were flown: number '2012' on 26 July 2014, number '2013' on 29 November 2014 and finally number '2015' on 19 December 2014.

Design[edit]

Characteristics[edit]

Chengdu J-20 prototype

The J-20 has a long and wide fuselage, with the chiseled nose section and a frameless canopy resembling that of the F-22 Raptor. Immediately behind the cockpit are low observable intakes. All-moving canard surfaces with pronounced dihedral are placed behind the intake ramps, followed by leading edge extensions merging into delta wing with forward-swept trailing edges. The aft section features twin, outward canted all-moving fins, short but deep ventral strakes, and conventional round engine nozzles.[27][28]

In one paper published on a Chinese aerodynamic journal, a designer of J-20 described high instability as an important design criterion for J-20. A canard is used to achieve sustained pitch authority at high angle of attack, as traditional tail-plane would start to lose effectiveness.[29][30][31] This is because tail-plane would go into even higher angle-of-attack and stall, whereas canard can avoid this effect by deflecting to the same magnitude but opposite to the angle-of-attack.[32] A canard configuration can also provide good supersonic performance, excellent supersonic and transonic turn performance, and improved short-field landing performance compared to the conventional design.[33][34]

The same journal paper also explained how leading edge extensions and body lift are incorporated to enhance performance in a canard layout through interactions among vortices. One graph shows the configuration to generate 1.2 times the lift of an ordinary canard delta, and 1.8 times more lift than a pure delta configuration of similar size. This allows the use of a smaller wing, reducing supersonic aerodynamic drag without compromising transonic lift-to-drag ratio characteristics that are crucial to the aircraft's turn performance.[29][30][31]

Engines[edit]

The production version of the J-20's is believed to be the WS-15, a turbofan engine currently under development.[35][36][37] According to Global Security, the engine core, composed of high pressure compressors, the combustion chamber, and high pressure turbines were successfully tested in 2005.[38] An image of the core appeared in the 2006 Zhuhai Air Show.[37] Since 2012, China has reported numerous breakthroughs in development military turbofans and invested up to 20 billion US dollars in turbofan engine research and development.[39][40][41] The J-20 has the potential to rival the F-22A Raptor in performance once appropriate engines become available.[35][42]

Western analyst believe that the current prototypes are powered by WS-10 or the AL-31F engine.[2][42] China is a large importer of Russian-made jet engines, prompting rumors that China seeks to obtain AL-41 117S engines for the initial production of J-20 through Su-35 purchases.[35][43][44] However, these rumors have since been denied by China, and were proven as false.[45] It was also reported that Russia approached China in an unsuccessful bid to sell 117S engines during the 2012 Zhuhai Air Show.[46]

Avionics[edit]

The aircraft features a glass cockpit, with two main large color liquid crystal displays (LCD) situated side-by-side, three smaller auxiliary displays, and a wide-angle holographic head-up display (HUD).[47][48][49]

A PLAAF Tupolev Tu-204 testbed aircraft was seen featuring a J-20 nose cone. It is believed to house the Type 1475 (KLJ-5) active electronically scanned array (AESA) radar with 1856 transmit/receive modules.[50]

Prototype "2011" featured a revised nose section with elements resembling a IRST/EOTS system used to hunt low observable aircraft, and a metal finish that loosely reminds the radar absorbing Haze Paint first used on F-16s, and reportedly included sensor fusion technology.[51]

Armament[edit]

The main weapon bay is capable of housing both short and long-range air-to-air missiles (AAM) (PL-9, PL-12C/D & PL-21).

Two smaller lateral weapon bays behind the air inlets are intended for short-range AAMs (PL-9). These bays allow closure of the bay doors prior to firing the missile, thus enhancing stealth.[52]

No gun has yet been seen on any J-20 model and there have not been signs of provisions for one.[53]

Stealth[edit]

Analysts noted that J-20's nose and canopy use similar stealth shaping design as the F-22, yielding similar signature performance in a mature design at the front, while the aircraft's side and axi-symmetric engine nozzles may expose the aircraft to radar.[2][27][54] One prototype has been powered by WS-10G engines equipped with a different jagged-edge nozzles and tiles for greater stealth.[24]

Others have raised doubts about the use of canards on a low-observable design, stating that canards would guarantee radar detection and a compromise of stealth.[55][56] However, canards and low-observability are not mutually exclusive designs. Northrop Grumman's proposal for the U.S Navy's Advanced Tactical Fighter (ATF) incorporated canards on a stealthy airframe.[57][58] Lockheed Martin employed canards on a stealth airframe for the Joint Advanced Strike Technology (JAST) program during early development before dropping them due to complications with aircraft carrier recovery.[59][60] McDonnell Douglas and NASA's X-36 featured canards and was considered to be extremely stealthy.[61] Radar cross-section can be further reduced by controlling canard deflection through flight control software, as is done on the Eurofighter.[62][63]

The diverterless supersonic inlet (DSI) enables an aircraft to reach Mach 2.0 with a simpler intake than traditionally required, and improves stealth performance by eliminating radar reflections between the diverter and the aircraft's skin. Analysts have noted that the J-20 DSI reduces the need for application of radar absorbent materials.[64][65] Additionally, the "bump" surface reduces the engine's exposure to radar, significantly reducing a strong source of radar reflection.[66]

It is also suspected that China gained knowledge of stealth technology to develop the J-20 from an F-117 "Nighthawk" shot down over the Former Yugoslavia in 1999 as part of the NATO campaign against Serbia.[67]

Strategic implications[edit]

Political[edit]

The first test flight coincided with a visit by United States Secretary of Defense Robert Gates to China, and was initially interpreted by Pentagon officials as a possible signal to the visiting U.S. delegation. Speaking to reporters in Beijing, secretary Gates said "I asked President Hu about it directly, and he said that the test had absolutely nothing to do with my visit and had been a pre-planned test."[8][68] It was reported that President Hu seemed surprised by Gates' inquiry, prompting speculations that the test might have been a signal sent unilaterally by Chinese military.[69][70][71] Abraham M. Denmark of the Center for New American Security in Washington, along with Michael Swaine, an expert on the PLA and United States - China military relations, explained that senior officials are not involved in day-to-day micromanagement of aircraft development, so being unaware about the test should not be a surprise.[68]

Military[edit]

Robert Gates tried to play down significance of the aircraft by questioning how stealthy the J-20 may be, but admitted it would potentially "put some of our capabilities at risk, and we have to pay attention to them, we have to respond appropriately with our own programs."[72] The U.S. Director of National Intelligence James R. Clapper testified that the United States knew about the program for a "long time" and that the test flight was not a surprise.[73]

Loren B. Thompson felt that J-20's combination of forward stealth and long range puts America's surface assets at risk, and that a long-range maritime strike capability may cause the United States more concern than a short range air-superiority fighter like the F-22.[42][74] In its 2011 Annual Report to Congress, the Pentagon described the J-20 as "a platform capable of long range, penetrating strikes into complex air defense environments."[75] A 2012 report by the U.S.‐China Economic and Security Review Commission suggests that the United States may have underestimated the speed of development of the J-20 and several other Chinese military development projects.[76]

Observers are not able to reach a consensus on J-20's primary role. Based on initial photographs with exclusive focus on the aircraft's apparent size, early assumptions painted the J-20 as a F-111 equivalent with little to no air-to-air ability.[77][78][79][80][81] Others saw the J-20 as a potential air superiority fighter once appropriate engines become available.[8][27][82] More recent speculations look at J-20 as an air-to-air fighter with an emphasis on forward-aspect stealth, high-speed aerodynamics, range, a modest internal payload, and adequate agility for self-defense. The J-20 could threaten vulnerable tankers and ISR/C2 platforms, depriving America and its allies of radar coverage and strike range.[53]

Cyber security[edit]

In April 2009, a Wall Street Journal report indicated that, according to American government officials, information from the Lockheed Martin F-35 Lightning II was compromised by unknown attackers that allegedly appeared to originate from China.[83] There is some speculation that the compromise of the Lockheed Martin F-35 program may have helped in the development of the J-20.[2][8][82]

Specifications[edit]

Data from Aviation Week & Space Technology[84]

General characteristics

  • Crew: one (pilot)
  • Length: 20 m (66.8 ft)
  • Wingspan: 13 m (44.2 ft)
  • Height: 4.45 m (14 ft 7 in)
  • Wing area: 78 m2 (840 sq ft)
  • Empty weight: 19,391 kg (42,750 lb)
  • Gross weight: 32,092 kg (70,750 lb)
  • Max takeoff weight: 36,288 kg (80,001 lb) upper estimate[2]
  • Fuel capacity: 11,340 kg (25,000 lb)
  • Powerplant: 2 × Saturn AL-31F (prototype) or Xian WS-15 (production) afterburning turbofans, 76.18 kN (17,125 lbf) thrust each dry, 122.3 or 179.9 kN (27,500 or 40,450 lbf) with afterburner
  • Wing loading: 410 kg/m2 (84 lb/sq ft)
  • Thrust/weight: 0.94 (prototype with interim engines)

Armament

  • PL-12 Medium Range AAM

See also[edit]

External images
J-20 Flight Testing
J-20 undergoing flight testing from ifeng.com, 2015.[86]
Aircraft of comparable role, configuration and era
Related lists

References[edit]

Notes[edit]

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Bibliography[edit]

External links[edit]