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Description
The Chengdu J-20 (Chinese: 歼-20; pinyin: Jiān-Èrlíng), also known as Mighty Dragon (Chinese: 威龙; pinyin: Wēilóng),[8][9][10] is a single-seat, twinjet, all-weather, stealth,[11] fifth-generation fighter aircraft developed by China's Chengdu Aerospace Corporation for the People's Liberation Army Air Force (PLAAF).[4] The J-20 is designed as an air superiority fighter with precision strike capability;[12] it descends from the J-XX program of the 1990s.[13]
The J-20 made its maiden flight on 11 January 2011,[1][2] and was officially revealed at the 2016 China International Aviation & Aerospace Exhibition.[14] The aircraft entered service in March 2017,[4] and began its combat training phase in September 2017.[15] The first J-20 combat unit was formed in February 2018.[4]
The J-20 is the world's third operational fifth-generation stealth fighter aircraft after the F-22 and F-35.[16]

Development
The J-20 emerged from the late-1990s J-XX program. In 2008, the PLAAF endorsed Chengdu Aerospace Corporation's proposal, Project 718; Shenyang's proposed aircraft was larger than the J-20.[13] Chengdu had previously used the double-canard configuration in the J-9, its first design and cancelled in the 1970s, and the J-10.[17][18]
In 2009, a senior PLAAF official revealed that the first flight was expected in 2010–11, with a service entry date by 2019.[19] On 22 December 2010, the first J-20 prototype underwent high speed taxiing tests outside the Chengdu Aircraft Design Institute.[5][20] Three months later, the first J-20 prototype made its maiden flight in Chengdu.[1][2]
Several changes were made to J-20 prototypes, including new low-observable intake and stealth coating, as well as redesigned vertical stabilizers in 2014. Analysts noted new equipment and devices for multi-role operations such as integrated targeting pods for precision-guided munition, and six additional passive infrared sensors can also be spotted around the aircraft.[21] In December 2015, the low rate initial production (LRIP) version of J-20 had been spotted by a military observer.[22]
Chinese state media reported in October 2017 that the designs of J-20 had been finalized, and is ready for mass production as well as being combat-ready.[23]
In January 2019, Chinese media reported that a twin-seat variant of the J-20 is rumored to be in development for use in tactical bombing, electronic warfare and carrier strike roles.[24]
In November 2019, a J-20 painted in yellow primer coating was spotted during its flight testing by defense observers at the Chengdu Aerospace Corporation manufacturing facility. The aircraft is equipped with new variant of WS-10 Taihang engines with serrated afterburner nozzles to enhance stealth.[25][26] Report indicated Chengdu Aerospace Corporation terminated the manufacturing of J-20 with Russian engines in mid-2019.[27]
Chinese media reported that a new variant of the J-20, the J-20B, was unveiled on July 8, 2020, and entered mass production the same day. The only change mentioned was that the J-20B was to be equipped with thrust vectoring control.[28] Conflicting reports emerged regarding the exact engine type. Analyst Andreas Rupprecht expressed skepticism regarding the use of Russian engines on J-20, as he believes that the J-20 is using a variant of the WS-10 which he called the WS-10C. This engine has improved thrust, stealthier serrated afterburner nozzles, and higher reliability, but it is not designed for thrust vectoring unlike the WS-10 TVC demonstrated on a J-10 at the 2018 China International Aviation & Aerospace Exhibition.[29] Analyst Jamie Hunter believed the new engine type is what he called WS-10B-3, a Chinese-made thrust vectoring engine demonstrated on the 2018 Zhuhai Airshow.[27]
In January 2021, South China Morning Post reported that China will replace Russian engines on the J-20 stealth fighter with a type of Chinese engine called WS-10C.[30][31] In June 2021, Chinese media confirmed that an aviation brigade is assigned with the enhanced J-20A variant that integrates domestic WS-10C engines.[32] Despite the replacement, WS-10C is considered another interim solution before Xian WS-15 passes evaluations. Moreover, WS-10C will not be equipped on the J-20B, the thrust-vectoring version of J-20 that entered mass production in 2019, which still required further testing. Overall, Chinese engineers believe WS-10C is comparable with AL-31F in performance,[33][34] and the replacement would also reduce China's dependency on Russian engines.[34] The WS-10C-powered J-20 was officially showcased to the public on 28 September 2021 at Zhuhai Airshow.[33][35][36]
In February 2021, a South China Morning Post infographic depicted a twin-seat J-20 variant powered by thrust vectoring WS-10C.[37]

Design
The J-20 has a long and blended fuselage, with a chiseled nose section and a frameless canopy. Immediately behind the cockpit are low observable intakes. All-moving canard surfaces with pronounced dihedral are placed behind the intakes, followed by leading edge extensions merging into the delta wing with forward-swept trailing edges. The aft section has twin outward canted all-moving fins, short but deep ventral strakes, and conventional or low observable engine exhausts.[38][39][12]
One important design criterion for the J-20 is high instability.[40][41] This requires sustained pitch authority at a high angle of attack, in which a conventional tail-plane would lose effectiveness due to stalling. On the other hand, a canard can deflect opposite to the angle of attack, avoiding stall and thereby maintaining control.[42] A canard design is also known to provide good supersonic performance, excellent supersonic and transonic turn performance, and improved short-field landing performance compared to the conventional delta wing design.[43][44]
Leading edge extensions and body lift are incorporated to enhance performance in a canard layout. This combination is said by the designer to generate 1.2 times the lift of an ordinary canard delta, and 1.8 times more lift than an equivalent sized pure delta configuration. The designer claims such a combination allows the use of a smaller wing, reducing supersonic drag without compromising transonic lift-to-drag characteristics that are crucial to the aircraft's turn performance.[40][41][45]
The usage of bubble canopy, extensive flight-control surfaces, canard configuration for angle-of-attack control indicates J-20's intention to operate in air-superiority missions and within-visual-range engagements. Chief test pilot Li Gang of the J-20 describes the aircraft as having comparable maneuverability to the Chengdu J-10 while being significantly better at low-observable (LO) performance. The J-20 is a multirole air superiority fighter, with the interceptor role only being one of the options.[12]

Avionics and Cockpit
The avionics of J-20 aims to obtain situational awareness through advanced sensor fusion while denying situational awareness to the adversary through stealth and electronic warfare. J-20 features an integrated avionic suite consisting of multi-spectral sensors capable of providing an omnidirectional coverage.[12] Official information on the type of radar that J-20s use have not yet been released publicly. Some analysts believed that J-20s used Type 1475 (KLJ-5) active electronically scanned array (AESA) radar with 1856 transmit/receive modules,[46] but more recent information's revealed that this radar was designed for upgraded versions of J-11D.[47] Other analysts point out that, based on nose cross-section of J-20 and known data about a single transmit/receive module surface in the J-16's AESA radar-system, J-20s likely fit 2000–2200 transmit/receive modules.[48]
Prototypes after application "2011" and production models feature revised nose section with an electro-optical/infra-red targeting system and an advanced communications suite on top of the aircraft enables it to datalink with other friendly platforms in service, such as airborne early warning drones. Six electro-optic sensors called Distributed Aperture System[a] similar to EODAS can provide 360-degree coverage for pilot with sensor fusion system combining radar signal with IR image in order to provide better situational awareness.[11][49] The combination of an integrated targeting pod with spherically located passive-optical tracking system is reported similar to the design concept of Lockheed Martin F-35's avionic suite.[50] Beijing A Star Science and Technology has developed the EOTS-86 electro-optical targeting system and Electro-Optical Distributed Aperture System for the J-20 and potentially other PLAAF fighters to detect and intercept stealth aircraft.[51]
The aircraft features a glass cockpit, with one primary large color liquid-crystal display (LCD) touchscreen, three smaller auxiliary displays, and a wide-angle holographic heads-up display (HUD).[52][53][54] The size of the primary LCD screen is 610 mm × 230 mm (24 in × 9 in), or 650 mm (25.63 in) by the diagonal, with two systems for redundant illumination.[55]

Armament
The main weapon bay is capable of housing both short and long-range air-to-air missiles (AAM; PL-9, PL-12C/D & PL-15 – PL-21) while the two smaller lateral weapon bays behind the air inlets are intended for short-range AAMs (PL-10). These side bays allow closure of the bay doors prior to firing the missile, thus allowing the missile to be fired in the shortest time possible as well as enhancing stealth.[56][57] The J-20 is reported to lack an internal autocannon or rotary cannon, suggesting the aircraft is not intended to be used in short range dogfight engagements with other aircraft but engage them with from long standoff ranges with missiles such as the PL-15 and PL-21.[58][59][60] J-20 will likely use air-to-air missiles to engage in air superiority combat with other aircraft, as well as destroying high-value airborne assets. Supplemental missions may include launching anti-radiation missiles and air-to-ground munitions for precision strike missions.[61]
While the fighter typically carries weapons internally, the wings include four hardpoints to extend ferrying range by carrying auxiliary fuel tanks.[62] However, much like the F-22, the J-20 is unlikely to carry fuel tanks on combat missions due to its vulnerability in such a configuration, thus this configuration remains valuable for peacetime operations, such as transiting between airbases.[63] The fighter is able to carry four medium/long range AAMs in main bay and short-range missile one in each lateral weapon bay of the aircraft.[64] A staggered arrangement with six PL-15s is possible depending on the rail launcher for missile mounted in the future.[65]

Engines
The J-20 entered production powered by a Saturn AL-31 variant,[68] reportedly the AL-31FM2[70] with a "special power setting" thrust of 145 kN (32,600 lbf).[71] AL-31 was a temporary solution before China could produce its own indigenous engine of comparable performance. Eventually, AL-31 was replaced by Chinese WS-10 in September 2019.[33]
The Shenyang WS-10 has also powered various aircraft. The WS-10B reportedly powered low rate initial production aircraft.[66] The WS-10 may have replaced the AL-31 in mid-2019.[68] Flights with prototypes[72] powered by the WS-10C were underway by November 2020.[73] The WS-10C was expected to replace the AL-31 as the interim engine in 2021.[72] In June 2021, Chinese media confirmed WS-10C engines are incorporated into active service with J-20A jets, making WS-10C the third engine type used on the J-20 platform.[32] WS-10C features enhanced thrust of about 142 kN, mature and reliable design, and serrated afterburner nozzles that enhance rear-aspect stealth capabilities.[33][74]
There are conflicting reports concerning the powerplant of the TVC-equipped J-20B.[28] The powerplant has been identified as the AL-31FM2, or a variant of the WS-10; "WS-10C" by Andreas Rupprecht,[75] or "WS-10B-3" by Jamie Hunter. The TVC-equipped WS-10B-3 was demonstrated at the 2018 China International Aviation & Aerospace Exhibition.[27]
The intended powerplant for J-20 is the Xian WS-15[68] with a thrust of 180 kN.[76] The J-20 requires the WS-15 to supercruise.[67] As of August 2019, the WS-15 was in development.[68]
The aircraft is equipped with a retractable refueling probe embedded on the right side of the cockpit, to help the fighter to maintain stealth while flying greater distances.[77]

Stealth
Analysts noted that the J-20's airframe employs a holistic approach to reduce its radar cross-section (RCS). The chimed forebody, modified radar radome, and electroconductive canopy[12] use a stealth shaping, yielding signature performance in a mature design similar to F-22.[78] The diverterless supersonic inlets (DSI) leading into serpentine ducts can obscure the reflective surface of the engine from radar detections. Additional low observable features include a flat fuselage bottom holding an internal weapons bay, sawtooth edges on compartment doors, mesh coverings on cooling ports at the base of the vertical tails, embedded antennas, radar-absorbent material used as coatings.[12] While the aircraft's side and axisymmetric engine nozzles may expose the aircraft to radar,[38][79] one prototype in 2014 has been powered by WS-10 engines equipped with different jagged-edge nozzles and tiles for greater stealth.[80] J-20 production model with serrated WS-10C engine is also capable of mitigating negative effects on rear aspect stealth.[81]
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.[82][83] However, these critiques with respect to canard's RCS are largely unfounded.[12] 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.[84][85] 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.[86][87] McDonnell Douglas and NASA's X-36 featured canards and was considered to be extremely stealthy.[88] Radar cross-section can be further reduced by controlling canard deflection through flight control software, as is done on the Eurofighter.[89][90] Similarly, Chinese aerospace researchers also concluded that, in terms of stealth, canard delta configuration is comparable with that of the conventional design.[91] Defense observer Rick Joe believes J-20's configuration is stealthy, while the assumption of canard's inherently incompatibility with stealth is a popular postulation that lacks evidence.[81]
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.[92][93]
In May 2018, Indian Air Chief Marshal B.S. Dhanoa told a press conference that the radars on India's Su-30MKI fighters were "good enough" and could detect a J-20 from "several kilometers away", while answering a question on whether the J-20 posed a threat to India.[94] Analyst Justin Bronk from Royal United Services Institute noted that Chinese are possibly flying the J-20 with radar reflectors during peacetime for safety and training purposes due to the potential for accidents and identification from other aircraft or ground installations.[95] In a more recent report, Bronk also states that even with limited stealth, J-20 could hide and strike enemy critical platforms in an airspace with background clutter caused by non-stealth fighters and other electromagnetic noise.[61] Despite debate regarding J-20's stealth capability, it's agreed by military analysts that the J-20's stealth design is superior to that of Russian Su-57[12] while being more comparable to American F-22 and F-35, and could further enhance its stealth profile as the program matures.[96][97]

Operational History

Flight Testing
On 11 January 2011, the J-20 made its first flight, lasting about 15 minutes, with a Chengdu J-10B serving as the chase aircraft.[1][2] 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.[98] On 17 April 2011, a second test flight of an hour and 20 minutes took place.[99] On 5 May 2011, a 55-minute test flight was held that included retraction of the landing gear.[100]
On 26 February 2012, a J-20 performed various low-altitude maneuvers.[101] On 10 May 2012, a second prototype underwent high speed taxiing tests, and flight testing that began later that month.[102][103] On 20 October 2012, photographs of a new prototype emerged, featuring a different radome, which was speculated to house an AESA radar. In March 2013, images of the side weapon bays appeared, including a missile launch rail.[104][105]
On 16 January 2014, a J-20 prototype was revealed, showing a new intake and stealth coating, as well as redesigned vertical stabilizers, and an Electro-Optical Targeting System.[80][106][107] This particular aircraft, numbered '2011', performed its maiden flight on 1 March 2014 and is said to represent the initial pre-serial standard. By 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.
On 13 September 2015, a new prototype, marked '2016', began testing. It had noticeable improvements, such as apparently changed DSI bumps on the intakes, which save weight, complexity and radar signature. The DSI changes suggested the possibility of more powerful engines being used than on its predecessors, likely to be an advanced 14-ton thrust derivative of the Russian AL-31 or Chinese Shenyang WS-10 turbofan engines, though, by 2020 the J-20 is planned to use the 18–19 ton WS-15 engine, enabling the jet to super-cruise without using afterburners. The trapezoidal flight booms around the engines were enlarged, possibly to accommodate rearwards facing radars or electronic jamming equipment. The fuselage extends almost entirely up to the engine's exhaust nozzles. Compared to its "2014" and "2015" predecessors, the J-20's fuselage contains more of engine's surface area inside the stealthy fuselage, providing greater rear-facing stealth against enemy radar.[108]
In November 2015, a new J-20 prototype, numbered '2017', took to the sky. The most significant change in the new prototype is the reshaped cockpit canopy, which provides the pilot with greater visibility. The lack of other design changes suggest that "2017" is very close to the final J-20 production configuration. Since '2017' is likely the last J-20 prototype, low rate initial production of the J-20 is likely to begin in 2016.[109] It has been reported that the design of J-20 is already mature and will not directly use the 117S engine.[110]
As of March 2017 there were still a series of technical problems that needed to be tackled, including the reliability of its WS-15 engines, the aircraft's flight control system, stealth coatings and hull materials, and infrared sensor.[111]

Production
In late December 2015, a new J-20 numbered 2101 was spotted; it is believed to be the LRIP version of the aircraft.[22]
In October 2017, Chinese media reported that Chengdu Aerospace Corporation (CAC) initiated a series production for the J-20 and is on a path towards achieving full operational capability with the People's Liberation Army Air Force (PLAAF).[112][113] Initially, the lack of a suitable indigenously produced engine hindered the mass production of the J-20, however in September 2018, it was reported that issues with the development of the WS-15 engine, particularly the reliability of the turbine blades overheating at top speeds are fixed and after further minor refinements it should be ready for widespread installation by the end of 2018.[114]
In 2019, Chengdu Aerospace Corporation began to manufacture J-20 fitted with Chinese-made WS-10 Taihang engines.[25] J-20s manufactured after mid-2019 are no longer fitted with Russian AL-31F turbofan engines.[27] In June 2021, J-20A with Chinese-made WS-10C engines are incorporated into active service.[32] As of July 2021, it's estimated that 150 units of J-20 fighters have been incorporated into PLAAF service.[115]

Deployment
At least six J-20s are in active service, with tail numbers 78271-78276 identified. Another six were believed ready to be delivered by end of Dec 2016.[116] On 9 March 2017, Chinese officials confirmed that the J-20 had entered service in the Chinese air force. It is anticipated that before 2020 China be equipped with the Chengdu J-20 low observable combat aircraft. The International Institute for Strategic Studies (IISS) has proposed that the USA could lose its lead on operational stealth aircraft.[117]
The J-20 officially entered service in September 2017[15] making China the second country in the world—after the United States—and the first in Asia to field an operational fifth-generation stealth aircraft.[16]
The PLAAF began inducting J-20s into combat units in February 2018. The aircraft entered service with the 9th Air Brigade based at Wuhu Air Base, Anhui province in late 2018 – March 2019, replacing Su-30MKK fighters previously deployed there.[4][118]
On 27 August 2019, the Central Military Commission of the People's Liberation Army have approved the J-20 as the PLAN's future primary fighter, beating out the FC-31. Arguments for the J-20 state that the plane is far more advanced, longer ranged and carries a heavier payload than the FC-31, while those supporting the FC-31 argued that it is cheaper, lighter and far more maneuverable than the J-20. It is likely that the J-20 would be commissioned upon the Type 002 aircraft carrier under construction, however, the length of the J-20 means that it has to be shortened to be considered operable on an aircraft carrier.[119]

Training
Pilot training for the J-20 started as early as March 2017, after the fighter entered limited service in the initial operational capability (IOC) phase. During the IOC phase, the fighters equipped with radar reflectors, also known as Luneburg lens to enlarge and conceal the actual radar cross section.[120][95]
The J-20 participated in its first combat exercise in January 2018, practicing beyond-visual-range maneuvers against China's fourth-generation fighters such as J-16 and J-10C. The exercise was reported to be realistic.[15] Training with mixed generations allow pilots to become familiar with fifth-generation aircraft, and to develop tactics both for and against them.[121] Chinese Ministry of National Defense also revealed that J-20 has conducted night confrontation missions during several coordinated tactical training exercises.[122]
The J-20 participated in its first over-ocean combat exercise in May 2018.[123]

Strategic Implications

Political
The first test flight coincided with a visit by United States Secretary of Defense Robert Gates to China, and was initially interpreted by the Pentagon as a possible signal to the visiting US 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 there had been a pre-planned test."[124][125] Hu seemed surprised by Gates' inquiry, prompting speculations that the test might have been a signal sent unilaterally by the Chinese military.[126][127][128] 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 management of aircraft development and were unaware of the test.[125][61]

Military
Robert Gates downplayed the significance of the aircraft by questioning how stealthy the J-20 may be, but stated the J-20 would "put some of our capabilities at risk, and we have to pay attention to them, we have to respond appropriately with our own programs."[129] 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.[130]
In 2011, Loren B. Thompson, echoed by a 2015 RAND Corporation report, 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.[131][132][133] 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."[134] 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.[135]
Observers were not able to reach a consensus on J-20's primary role.[136][137][138] Based on initial photographs with focus on the aircraft's size, early speculations referred to the J-20 as an F-111 equivalent with little to no air-to-air ability. Others saw the J-20 as a potential air superiority fighter once appropriate engines become available.[38][124][139] More recent speculations refer to the J-20 as an air-to-air fighter with an emphasis on forward stealth, high-speed aerodynamics, range, and adequate agility. The J-20 with its long range missile armament could threaten vulnerable tankers and ISR/C2 platforms such as the Boeing KC-135 Stratotanker and Boeing E-3 Sentry AWACS, depriving Washington of radar coverage and strike range.[57] However one of these targets, the Northrop Grumman E-2D Advanced Hawkeye, is reported to be optimized for spotting fighter sized stealth aircraft such as the J-20.[140]
After the deployment announcement, several analysts noted that experience that the PLAAF will gain with the J-20 will give China a significant edge over India, Japan, and South Korea, which have struggled to design and produce their own fifth-generation fighters on schedule.[141] However, despite the failure of their indigenous projects, Japan and South Korea operate the imported F-35A, negating this potential technological disparity.[142][143] United States Marine Corps created a full-scale replica (FSR) of a Chengdu J-20 in December 2018. The replica was spotted parked outside the Air Dominance Center at Savannah/Hilton Head International Airport in Georgia. The United States Marine Corps later confirmed that the aircraft was built for training.[144]
Defense media
The J-20 has enabled a wide range of speculation around its role, capability, and technological parity for a prolonged period, due to the secrecy intentionally dictated by the Chinese military and manufacturer.[81] Although the fighter has been designated as an air-superiority fighter with strike capability by the Chinese Air Force, many military observers in the West didn't believe it and opted to classify the J-20 as an interceptor or dedicated striker, due to discomfort or disbelief that the Chinese military has the intention to design a fighter with symmetric capability against contemporary Western fifth-generation fighters.[145] These notions regarding the roles, capability, and linage of the J-20 platform were reflected by the defense media, which Rick Joe argues were incorrect, due to the usage of overestimated size data, or lack of understanding on aircraft technologies, such as the accusation of J-20 being a copy of Mig 1.44 or F-117. Despite many claims on J-20 are often incorrectly attributed or unjustified, they remain unchanged in defense media for the past decade.[81]
Western sources also contribute the idea that J-20 is only optimized for anti-access/aerial denial (A2/AD) engagements, while Chinese sources universally describe J-20 as an air-superiority fighter meant to engage other fighters.[12] Rod Lee, research director at the China Aerospace Studies Institute of the Air University, believes J-20 is intended to be primarily used for destroying high-value airborne assets, which is an alternative way of establishing air superiority. Supplemental missions may include launching anti-radiation missiles and air-to-ground munitions. Rod Lee believes J-20 has the maneuverability to engage air superiority combat with other aircraft, but PLAAF has de-emphasized the traditional attrition warfare while advocating the "systems destruction" approach because they believe it is more effective.[61] Matthew Jouppi of Aviation Week noted the ill-informed assumptions that existed in defense circles and argued that the United States has not adequately addressed threats posed by the increasing Chinese airpower.[12]

Controversy
In April 2009, a report in The Wall Street Journal indicated that, according to the Pentagon, information from the Lockheed Martin F-35 Lightning II had been compromised by unknown attackers that appeared to originate from China. There is some speculation that the compromise of the F-35 program may have helped in the development of the J-20.[78][124][139][146] See also hereinabove under Avionics and cockpit.
Visual physical configuration and stealth shaping have been claimed to be influenced by foreign aircraft, including the F-22, F-35, F-117, Mig 1.44, Mig-31, Rafale and Eurofighter Typhoon. Rick Joe believes that the J-20's external physical configuration is a logical development of Chengdu's previous canard-delta designs: the Chengdu J-9 - particularly the "twin tail, side intake, canard delta" J-9V-II - from the 1960s and 1970s, and the Chengdu J-10. Furthermore, Joe states that stealth shaping is a "much more universal and consistent trait that leaves limited room for variety", and that future international designs will likely reflect this.[81]

Operators
China
People's Liberation Army Air Force – 50 delivered as of December 2019.[147] 150 in service estimated as of 2021.[6][115]
9th Air Brigade, Wuhu Air Base, Anhui[118]
172nd Aviation Brigade, Cangzhou Airbase, Cangzhou, Hebei[148]
176th Aviation Brigade, Dingxin Airbase, Gansu[148]

Specifications
General characteristics
Crew: one (pilot)
Length: 21.2 m (69 ft 7 in)
Wingspan: 13.01 m (42 ft 8 in)
Height: 4.69 m (15 ft 5 in)
Wing area: 73 m2 (790 sq ft)
Empty weight: 17,000 kg (37,479 lb)
Gross weight: 25,000 kg (55,116 lb)
Max takeoff weight: 37,000 kg (81,571 lb)
Fuel capacity: 12,000 kg (26,000 lb) internally
Powerplant: 2 × Saturn AL-31FM2[68][70][72] afterburning turbofan, 123 kN (28,000 lbf) with afterburner
Powerplant: 2 × Shenyang WS-10C[27][32] afterburning turbofan, 147 kN (33,000 lbf) with afterburner
Performance
Maximum speed: Mach 2.0[150]
Range: 5,500 km (3,400 mi, 3,000 nmi) with 2 external fuel tanks
Combat range: 2,000 km (1,200 mi, 1,100 nmi)
Service ceiling: 20,000 m (66,000 ft)
g limits: +9/-3
Rate of climb: 304[8] m/s (59,800 ft/min)
Wing loading: 340 kg/m2 (69 lb/sq ft)
Thrust/weight: 0.92 (1.12 with loaded weight and 50% fuel) with WS-10C/AL-31FM2 (estimated)
Armament
Maximum weapon capacity: 11,000 kg (24,000 lb)
Internal weapon bays
PL-10 short range AAM[151]
PL-12 Medium Range AAM[152]
PL-15 BVR long range AAM
PL-21 Long Range AAM[152]
LS-6 Precision-guided bomb
Anti-radiation missile[61]
External hardpoints
4× under-wing pylon capable of carrying drop tanks.
Avionics
Type 1475 (KLJ-5) Active Electronically Scanned Array Radar
EOTS-86 electro-optical targeting system (EOTS)[51]
EORD-31 Infrared search and track[51]
Distributed aperture system[141]

Description
The Chengdu J-20 (Chinese: 歼-20; pinyin: Jiān-Èrlíng), also known as Mighty Dragon (Chinese: 威龙; pinyin: Wēilóng),[8][9][10] is a single-seat, twinjet, all-weather, stealth,[11] fifth-generation fighter aircraft developed by China's Chengdu Aerospace Corporation for the People's Liberation Army Air Force (PLAAF).[4] The J-20 is designed as an air superiority fighter with precision strike capability;[12] it descends from the J-XX program of the 1990s.[13]
The J-20 made its maiden flight on 11 January 2011,[1][2] and was officially revealed at the 2016 China International Aviation & Aerospace Exhibition.[14] The aircraft entered service in March 2017,[4] and began its combat training phase in September 2017.[15] The first J-20 combat unit was formed in February 2018.[4]
The J-20 is the world's third operational fifth-generation stealth fighter aircraft after the F-22 and F-35.[16]

Development
The J-20 emerged from the late-1990s J-XX program. In 2008, the PLAAF endorsed Chengdu Aerospace Corporation's proposal, Project 718; Shenyang's proposed aircraft was larger than the J-20.[13] Chengdu had previously used the double-canard configuration in the J-9, its first design and cancelled in the 1970s, and the J-10.[17][18]
In 2009, a senior PLAAF official revealed that the first flight was expected in 2010–11, with a service entry date by 2019.[19] On 22 December 2010, the first J-20 prototype underwent high speed taxiing tests outside the Chengdu Aircraft Design Institute.[5][20] Three months later, the first J-20 prototype made its maiden flight in Chengdu.[1][2]
Several changes were made to J-20 prototypes, including new low-observable intake and stealth coating, as well as redesigned vertical stabilizers in 2014. Analysts noted new equipment and devices for multi-role operations such as integrated targeting pods for precision-guided munition, and six additional passive infrared sensors can also be spotted around the aircraft.[21] In December 2015, the low rate initial production (LRIP) version of J-20 had been spotted by a military observer.[22]
Chinese state media reported in October 2017 that the designs of J-20 had been finalized, and is ready for mass production as well as being combat-ready.[23]
In January 2019, Chinese media reported that a twin-seat variant of the J-20 is rumored to be in development for use in tactical bombing, electronic warfare and carrier strike roles.[24]
In November 2019, a J-20 painted in yellow primer coating was spotted during its flight testing by defense observers at the Chengdu Aerospace Corporation manufacturing facility. The aircraft is equipped with new variant of WS-10 Taihang engines with serrated afterburner nozzles to enhance stealth.[25][26] Report indicated Chengdu Aerospace Corporation terminated the manufacturing of J-20 with Russian engines in mid-2019.[27]
Chinese media reported that a new variant of the J-20, the J-20B, was unveiled on July 8, 2020, and entered mass production the same day. The only change mentioned was that the J-20B was to be equipped with thrust vectoring control.[28] Conflicting reports emerged regarding the exact engine type. Analyst Andreas Rupprecht expressed skepticism regarding the use of Russian engines on J-20, as he believes that the J-20 is using a variant of the WS-10 which he called the WS-10C. This engine has improved thrust, stealthier serrated afterburner nozzles, and higher reliability, but it is not designed for thrust vectoring unlike the WS-10 TVC demonstrated on a J-10 at the 2018 China International Aviation & Aerospace Exhibition.[29] Analyst Jamie Hunter believed the new engine type is what he called WS-10B-3, a Chinese-made thrust vectoring engine demonstrated on the 2018 Zhuhai Airshow.[27]
In January 2021, South China Morning Post reported that China will replace Russian engines on the J-20 stealth fighter with a type of Chinese engine called WS-10C.[30][31] In June 2021, Chinese media confirmed that an aviation brigade is assigned with the enhanced J-20A variant that integrates domestic WS-10C engines.[32] Despite the replacement, WS-10C is considered another interim solution before Xian WS-15 passes evaluations. Moreover, WS-10C will not be equipped on the J-20B, the thrust-vectoring version of J-20 that entered mass production in 2019, which still required further testing. Overall, Chinese engineers believe WS-10C is comparable with AL-31F in performance,[33][34] and the replacement would also reduce China's dependency on Russian engines.[34] The WS-10C-powered J-20 was officially showcased to the public on 28 September 2021 at Zhuhai Airshow.[33][35][36]
In February 2021, a South China Morning Post infographic depicted a twin-seat J-20 variant powered by thrust vectoring WS-10C.[37]

Design
The J-20 has a long and blended fuselage, with a chiseled nose section and a frameless canopy. Immediately behind the cockpit are low observable intakes. All-moving canard surfaces with pronounced dihedral are placed behind the intakes, followed by leading edge extensions merging into the delta wing with forward-swept trailing edges. The aft section has twin outward canted all-moving fins, short but deep ventral strakes, and conventional or low observable engine exhausts.[38][39][12]
One important design criterion for the J-20 is high instability.[40][41] This requires sustained pitch authority at a high angle of attack, in which a conventional tail-plane would lose effectiveness due to stalling. On the other hand, a canard can deflect opposite to the angle of attack, avoiding stall and thereby maintaining control.[42] A canard design is also known to provide good supersonic performance, excellent supersonic and transonic turn performance, and improved short-field landing performance compared to the conventional delta wing design.[43][44]
Leading edge extensions and body lift are incorporated to enhance performance in a canard layout. This combination is said by the designer to generate 1.2 times the lift of an ordinary canard delta, and 1.8 times more lift than an equivalent sized pure delta configuration. The designer claims such a combination allows the use of a smaller wing, reducing supersonic drag without compromising transonic lift-to-drag characteristics that are crucial to the aircraft's turn performance.[40][41][45]
The usage of bubble canopy, extensive flight-control surfaces, canard configuration for angle-of-attack control indicates J-20's intention to operate in air-superiority missions and within-visual-range engagements. Chief test pilot Li Gang of the J-20 describes the aircraft as having comparable maneuverability to the Chengdu J-10 while being significantly better at low-observable (LO) performance. The J-20 is a multirole air superiority fighter, with the interceptor role only being one of the options.[12]

Avionics and Cockpit
The avionics of J-20 aims to obtain situational awareness through advanced sensor fusion while denying situational awareness to the adversary through stealth and electronic warfare. J-20 features an integrated avionic suite consisting of multi-spectral sensors capable of providing an omnidirectional coverage.[12] Official information on the type of radar that J-20s use have not yet been released publicly. Some analysts believed that J-20s used Type 1475 (KLJ-5) active electronically scanned array (AESA) radar with 1856 transmit/receive modules,[46] but more recent information's revealed that this radar was designed for upgraded versions of J-11D.[47] Other analysts point out that, based on nose cross-section of J-20 and known data about a single transmit/receive module surface in the J-16's AESA radar-system, J-20s likely fit 2000–2200 transmit/receive modules.[48]
Prototypes after application "2011" and production models feature revised nose section with an electro-optical/infra-red targeting system and an advanced communications suite on top of the aircraft enables it to datalink with other friendly platforms in service, such as airborne early warning drones. Six electro-optic sensors called Distributed Aperture System[a] similar to EODAS can provide 360-degree coverage for pilot with sensor fusion system combining radar signal with IR image in order to provide better situational awareness.[11][49] The combination of an integrated targeting pod with spherically located passive-optical tracking system is reported similar to the design concept of Lockheed Martin F-35's avionic suite.[50] Beijing A Star Science and Technology has developed the EOTS-86 electro-optical targeting system and Electro-Optical Distributed Aperture System for the J-20 and potentially other PLAAF fighters to detect and intercept stealth aircraft.[51]
The aircraft features a glass cockpit, with one primary large color liquid-crystal display (LCD) touchscreen, three smaller auxiliary displays, and a wide-angle holographic heads-up display (HUD).[52][53][54] The size of the primary LCD screen is 610 mm × 230 mm (24 in × 9 in), or 650 mm (25.63 in) by the diagonal, with two systems for redundant illumination.[55]

Armament
The main weapon bay is capable of housing both short and long-range air-to-air missiles (AAM; PL-9, PL-12C/D & PL-15 – PL-21) while the two smaller lateral weapon bays behind the air inlets are intended for short-range AAMs (PL-10). These side bays allow closure of the bay doors prior to firing the missile, thus allowing the missile to be fired in the shortest time possible as well as enhancing stealth.[56][57] The J-20 is reported to lack an internal autocannon or rotary cannon, suggesting the aircraft is not intended to be used in short range dogfight engagements with other aircraft but engage them with from long standoff ranges with missiles such as the PL-15 and PL-21.[58][59][60] J-20 will likely use air-to-air missiles to engage in air superiority combat with other aircraft, as well as destroying high-value airborne assets. Supplemental missions may include launching anti-radiation missiles and air-to-ground munitions for precision strike missions.[61]
While the fighter typically carries weapons internally, the wings include four hardpoints to extend ferrying range by carrying auxiliary fuel tanks.[62] However, much like the F-22, the J-20 is unlikely to carry fuel tanks on combat missions due to its vulnerability in such a configuration, thus this configuration remains valuable for peacetime operations, such as transiting between airbases.[63] The fighter is able to carry four medium/long range AAMs in main bay and short-range missile one in each lateral weapon bay of the aircraft.[64] A staggered arrangement with six PL-15s is possible depending on the rail launcher for missile mounted in the future.[65]

Engines
The J-20 entered production powered by a Saturn AL-31 variant,[68] reportedly the AL-31FM2[70] with a "special power setting" thrust of 145 kN (32,600 lbf).[71] AL-31 was a temporary solution before China could produce its own indigenous engine of comparable performance. Eventually, AL-31 was replaced by Chinese WS-10 in September 2019.[33]
The Shenyang WS-10 has also powered various aircraft. The WS-10B reportedly powered low rate initial production aircraft.[66] The WS-10 may have replaced the AL-31 in mid-2019.[68] Flights with prototypes[72] powered by the WS-10C were underway by November 2020.[73] The WS-10C was expected to replace the AL-31 as the interim engine in 2021.[72] In June 2021, Chinese media confirmed WS-10C engines are incorporated into active service with J-20A jets, making WS-10C the third engine type used on the J-20 platform.[32] WS-10C features enhanced thrust of about 142 kN, mature and reliable design, and serrated afterburner nozzles that enhance rear-aspect stealth capabilities.[33][74]
There are conflicting reports concerning the powerplant of the TVC-equipped J-20B.[28] The powerplant has been identified as the AL-31FM2, or a variant of the WS-10; "WS-10C" by Andreas Rupprecht,[75] or "WS-10B-3" by Jamie Hunter. The TVC-equipped WS-10B-3 was demonstrated at the 2018 China International Aviation & Aerospace Exhibition.[27]
The intended powerplant for J-20 is the Xian WS-15[68] with a thrust of 180 kN.[76] The J-20 requires the WS-15 to supercruise.[67] As of August 2019, the WS-15 was in development.[68]
The aircraft is equipped with a retractable refueling probe embedded on the right side of the cockpit, to help the fighter to maintain stealth while flying greater distances.[77]

Stealth
Analysts noted that the J-20's airframe employs a holistic approach to reduce its radar cross-section (RCS). The chimed forebody, modified radar radome, and electroconductive canopy[12] use a stealth shaping, yielding signature performance in a mature design similar to F-22.[78] The diverterless supersonic inlets (DSI) leading into serpentine ducts can obscure the reflective surface of the engine from radar detections. Additional low observable features include a flat fuselage bottom holding an internal weapons bay, sawtooth edges on compartment doors, mesh coverings on cooling ports at the base of the vertical tails, embedded antennas, radar-absorbent material used as coatings.[12] While the aircraft's side and axisymmetric engine nozzles may expose the aircraft to radar,[38][79] one prototype in 2014 has been powered by WS-10 engines equipped with different jagged-edge nozzles and tiles for greater stealth.[80] J-20 production model with serrated WS-10C engine is also capable of mitigating negative effects on rear aspect stealth.[81]
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.[82][83] However, these critiques with respect to canard's RCS are largely unfounded.[12] 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.[84][85] 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.[86][87] McDonnell Douglas and NASA's X-36 featured canards and was considered to be extremely stealthy.[88] Radar cross-section can be further reduced by controlling canard deflection through flight control software, as is done on the Eurofighter.[89][90] Similarly, Chinese aerospace researchers also concluded that, in terms of stealth, canard delta configuration is comparable with that of the conventional design.[91] Defense observer Rick Joe believes J-20's configuration is stealthy, while the assumption of canard's inherently incompatibility with stealth is a popular postulation that lacks evidence.[81]
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.[92][93]
In May 2018, Indian Air Chief Marshal B.S. Dhanoa told a press conference that the radars on India's Su-30MKI fighters were "good enough" and could detect a J-20 from "several kilometers away", while answering a question on whether the J-20 posed a threat to India.[94] Analyst Justin Bronk from Royal United Services Institute noted that Chinese are possibly flying the J-20 with radar reflectors during peacetime for safety and training purposes due to the potential for accidents and identification from other aircraft or ground installations.[95] In a more recent report, Bronk also states that even with limited stealth, J-20 could hide and strike enemy critical platforms in an airspace with background clutter caused by non-stealth fighters and other electromagnetic noise.[61] Despite debate regarding J-20's stealth capability, it's agreed by military analysts that the J-20's stealth design is superior to that of Russian Su-57[12] while being more comparable to American F-22 and F-35, and could further enhance its stealth profile as the program matures.[96][97]

Operational History

Flight Testing
On 11 January 2011, the J-20 made its first flight, lasting about 15 minutes, with a Chengdu J-10B serving as the chase aircraft.[1][2] 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.[98] On 17 April 2011, a second test flight of an hour and 20 minutes took place.[99] On 5 May 2011, a 55-minute test flight was held that included retraction of the landing gear.[100]
On 26 February 2012, a J-20 performed various low-altitude maneuvers.[101] On 10 May 2012, a second prototype underwent high speed taxiing tests, and flight testing that began later that month.[102][103] On 20 October 2012, photographs of a new prototype emerged, featuring a different radome, which was speculated to house an AESA radar. In March 2013, images of the side weapon bays appeared, including a missile launch rail.[104][105]
On 16 January 2014, a J-20 prototype was revealed, showing a new intake and stealth coating, as well as redesigned vertical stabilizers, and an Electro-Optical Targeting System.[80][106][107] This particular aircraft, numbered '2011', performed its maiden flight on 1 March 2014 and is said to represent the initial pre-serial standard. By 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.
On 13 September 2015, a new prototype, marked '2016', began testing. It had noticeable improvements, such as apparently changed DSI bumps on the intakes, which save weight, complexity and radar signature. The DSI changes suggested the possibility of more powerful engines being used than on its predecessors, likely to be an advanced 14-ton thrust derivative of the Russian AL-31 or Chinese Shenyang WS-10 turbofan engines, though, by 2020 the J-20 is planned to use the 18–19 ton WS-15 engine, enabling the jet to super-cruise without using afterburners. The trapezoidal flight booms around the engines were enlarged, possibly to accommodate rearwards facing radars or electronic jamming equipment. The fuselage extends almost entirely up to the engine's exhaust nozzles. Compared to its "2014" and "2015" predecessors, the J-20's fuselage contains more of engine's surface area inside the stealthy fuselage, providing greater rear-facing stealth against enemy radar.[108]
In November 2015, a new J-20 prototype, numbered '2017', took to the sky. The most significant change in the new prototype is the reshaped cockpit canopy, which provides the pilot with greater visibility. The lack of other design changes suggest that "2017" is very close to the final J-20 production configuration. Since '2017' is likely the last J-20 prototype, low rate initial production of the J-20 is likely to begin in 2016.[109] It has been reported that the design of J-20 is already mature and will not directly use the 117S engine.[110]
As of March 2017 there were still a series of technical problems that needed to be tackled, including the reliability of its WS-15 engines, the aircraft's flight control system, stealth coatings and hull materials, and infrared sensor.[111]

Production
In late December 2015, a new J-20 numbered 2101 was spotted; it is believed to be the LRIP version of the aircraft.[22]
In October 2017, Chinese media reported that Chengdu Aerospace Corporation (CAC) initiated a series production for the J-20 and is on a path towards achieving full operational capability with the People's Liberation Army Air Force (PLAAF).[112][113] Initially, the lack of a suitable indigenously produced engine hindered the mass production of the J-20, however in September 2018, it was reported that issues with the development of the WS-15 engine, particularly the reliability of the turbine blades overheating at top speeds are fixed and after further minor refinements it should be ready for widespread installation by the end of 2018.[114]
In 2019, Chengdu Aerospace Corporation began to manufacture J-20 fitted with Chinese-made WS-10 Taihang engines.[25] J-20s manufactured after mid-2019 are no longer fitted with Russian AL-31F turbofan engines.[27] In June 2021, J-20A with Chinese-made WS-10C engines are incorporated into active service.[32] As of July 2021, it's estimated that 150 units of J-20 fighters have been incorporated into PLAAF service.[115]

Deployment
At least six J-20s are in active service, with tail numbers 78271-78276 identified. Another six were believed ready to be delivered by end of Dec 2016.[116] On 9 March 2017, Chinese officials confirmed that the J-20 had entered service in the Chinese air force. It is anticipated that before 2020 China be equipped with the Chengdu J-20 low observable combat aircraft. The International Institute for Strategic Studies (IISS) has proposed that the USA could lose its lead on operational stealth aircraft.[117]
The J-20 officially entered service in September 2017[15] making China the second country in the world—after the United States—and the first in Asia to field an operational fifth-generation stealth aircraft.[16]
The PLAAF began inducting J-20s into combat units in February 2018. The aircraft entered service with the 9th Air Brigade based at Wuhu Air Base, Anhui province in late 2018 – March 2019, replacing Su-30MKK fighters previously deployed there.[4][118]
On 27 August 2019, the Central Military Commission of the People's Liberation Army have approved the J-20 as the PLAN's future primary fighter, beating out the FC-31. Arguments for the J-20 state that the plane is far more advanced, longer ranged and carries a heavier payload than the FC-31, while those supporting the FC-31 argued that it is cheaper, lighter and far more maneuverable than the J-20. It is likely that the J-20 would be commissioned upon the Type 002 aircraft carrier under construction, however, the length of the J-20 means that it has to be shortened to be considered operable on an aircraft carrier.[119]

Training
Pilot training for the J-20 started as early as March 2017, after the fighter entered limited service in the initial operational capability (IOC) phase. During the IOC phase, the fighters equipped with radar reflectors, also known as Luneburg lens to enlarge and conceal the actual radar cross section.[120][95]
The J-20 participated in its first combat exercise in January 2018, practicing beyond-visual-range maneuvers against China's fourth-generation fighters such as J-16 and J-10C. The exercise was reported to be realistic.[15] Training with mixed generations allow pilots to become familiar with fifth-generation aircraft, and to develop tactics both for and against them.[121] Chinese Ministry of National Defense also revealed that J-20 has conducted night confrontation missions during several coordinated tactical training exercises.[122]
The J-20 participated in its first over-ocean combat exercise in May 2018.[123]

Strategic Implications

Political
The first test flight coincided with a visit by United States Secretary of Defense Robert Gates to China, and was initially interpreted by the Pentagon as a possible signal to the visiting US 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 there had been a pre-planned test."[124][125] Hu seemed surprised by Gates' inquiry, prompting speculations that the test might have been a signal sent unilaterally by the Chinese military.[126][127][128] 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 management of aircraft development and were unaware of the test.[125][61]

Military
Robert Gates downplayed the significance of the aircraft by questioning how stealthy the J-20 may be, but stated the J-20 would "put some of our capabilities at risk, and we have to pay attention to them, we have to respond appropriately with our own programs."[129] 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.[130]
In 2011, Loren B. Thompson, echoed by a 2015 RAND Corporation report, 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.[131][132][133] 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."[134] 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.[135]
Observers were not able to reach a consensus on J-20's primary role.[136][137][138] Based on initial photographs with focus on the aircraft's size, early speculations referred to the J-20 as an F-111 equivalent with little to no air-to-air ability. Others saw the J-20 as a potential air superiority fighter once appropriate engines become available.[38][124][139] More recent speculations refer to the J-20 as an air-to-air fighter with an emphasis on forward stealth, high-speed aerodynamics, range, and adequate agility. The J-20 with its long range missile armament could threaten vulnerable tankers and ISR/C2 platforms such as the Boeing KC-135 Stratotanker and Boeing E-3 Sentry AWACS, depriving Washington of radar coverage and strike range.[57] However one of these targets, the Northrop Grumman E-2D Advanced Hawkeye, is reported to be optimized for spotting fighter sized stealth aircraft such as the J-20.[140]
After the deployment announcement, several analysts noted that experience that the PLAAF will gain with the J-20 will give China a significant edge over India, Japan, and South Korea, which have struggled to design and produce their own fifth-generation fighters on schedule.[141] However, despite the failure of their indigenous projects, Japan and South Korea operate the imported F-35A, negating this potential technological disparity.[142][143] United States Marine Corps created a full-scale replica (FSR) of a Chengdu J-20 in December 2018. The replica was spotted parked outside the Air Dominance Center at Savannah/Hilton Head International Airport in Georgia. The United States Marine Corps later confirmed that the aircraft was built for training.[144]
Defense media
The J-20 has enabled a wide range of speculation around its role, capability, and technological parity for a prolonged period, due to the secrecy intentionally dictated by the Chinese military and manufacturer.[81] Although the fighter has been designated as an air-superiority fighter with strike capability by the Chinese Air Force, many military observers in the West didn't believe it and opted to classify the J-20 as an interceptor or dedicated striker, due to discomfort or disbelief that the Chinese military has the intention to design a fighter with symmetric capability against contemporary Western fifth-generation fighters.[145] These notions regarding the roles, capability, and linage of the J-20 platform were reflected by the defense media, which Rick Joe argues were incorrect, due to the usage of overestimated size data, or lack of understanding on aircraft technologies, such as the accusation of J-20 being a copy of Mig 1.44 or F-117. Despite many claims on J-20 are often incorrectly attributed or unjustified, they remain unchanged in defense media for the past decade.[81]
Western sources also contribute the idea that J-20 is only optimized for anti-access/aerial denial (A2/AD) engagements, while Chinese sources universally describe J-20 as an air-superiority fighter meant to engage other fighters.[12] Rod Lee, research director at the China Aerospace Studies Institute of the Air University, believes J-20 is intended to be primarily used for destroying high-value airborne assets, which is an alternative way of establishing air superiority. Supplemental missions may include launching anti-radiation missiles and air-to-ground munitions. Rod Lee believes J-20 has the maneuverability to engage air superiority combat with other aircraft, but PLAAF has de-emphasized the traditional attrition warfare while advocating the "systems destruction" approach because they believe it is more effective.[61] Matthew Jouppi of Aviation Week noted the ill-informed assumptions that existed in defense circles and argued that the United States has not adequately addressed threats posed by the increasing Chinese airpower.[12]

Controversy
In April 2009, a report in The Wall Street Journal indicated that, according to the Pentagon, information from the Lockheed Martin F-35 Lightning II had been compromised by unknown attackers that appeared to originate from China. There is some speculation that the compromise of the F-35 program may have helped in the development of the J-20.[78][124][139][146] See also hereinabove under Avionics and cockpit.
Visual physical configuration and stealth shaping have been claimed to be influenced by foreign aircraft, including the F-22, F-35, F-117, Mig 1.44, Mig-31, Rafale and Eurofighter Typhoon. Rick Joe believes that the J-20's external physical configuration is a logical development of Chengdu's previous canard-delta designs: the Chengdu J-9 - particularly the "twin tail, side intake, canard delta" J-9V-II - from the 1960s and 1970s, and the Chengdu J-10. Furthermore, Joe states that stealth shaping is a "much more universal and consistent trait that leaves limited room for variety", and that future international designs will likely reflect this.[81]

Operators
China
People's Liberation Army Air Force – 50 delivered as of December 2019.[147] 150 in service estimated as of 2021.[6][115]
9th Air Brigade, Wuhu Air Base, Anhui[118]
172nd Aviation Brigade, Cangzhou Airbase, Cangzhou, Hebei[148]
176th Aviation Brigade, Dingxin Airbase, Gansu[148]

Specifications
General characteristics
Crew: one (pilot)
Length: 21.2 m (69 ft 7 in)
Wingspan: 13.01 m (42 ft 8 in)
Height: 4.69 m (15 ft 5 in)
Wing area: 73 m2 (790 sq ft)
Empty weight: 17,000 kg (37,479 lb)
Gross weight: 25,000 kg (55,116 lb)
Max takeoff weight: 37,000 kg (81,571 lb)
Fuel capacity: 12,000 kg (26,000 lb) internally
Powerplant: 2 × Saturn AL-31FM2[68][70][72] afterburning turbofan, 123 kN (28,000 lbf) with afterburner
Powerplant: 2 × Shenyang WS-10C[27][32] afterburning turbofan, 147 kN (33,000 lbf) with afterburner
Performance
Maximum speed: Mach 2.0[150]
Range: 5,500 km (3,400 mi, 3,000 nmi) with 2 external fuel tanks
Combat range: 2,000 km (1,200 mi, 1,100 nmi)
Service ceiling: 20,000 m (66,000 ft)
g limits: +9/-3
Rate of climb: 304[8] m/s (59,800 ft/min)
Wing loading: 340 kg/m2 (69 lb/sq ft)
Thrust/weight: 0.92 (1.12 with loaded weight and 50% fuel) with WS-10C/AL-31FM2 (estimated)
Armament
Maximum weapon capacity: 11,000 kg (24,000 lb)
Internal weapon bays
PL-10 short range AAM[151]
PL-12 Medium Range AAM[152]
PL-15 BVR long range AAM
PL-21 Long Range AAM[152]
LS-6 Precision-guided bomb
Anti-radiation missile[61]
External hardpoints
4× under-wing pylon capable of carrying drop tanks.
Avionics
Type 1475 (KLJ-5) Active Electronically Scanned Array Radar
EOTS-86 electro-optical targeting system (EOTS)[51]
EORD-31 Infrared search and track[51]
Distributed aperture system[141]