|J-20 flight at Airshow China 2016|
|Role||Stealth / multirole combat aircraft|
|Manufacturer||Chengdu Aerospace Corporation|
|First flight||11 January 2011|
|Introduction||10 March 2017|
|Primary user||People's Liberation Army Air Force|
|Number built||8 prototypes and|
20+ initial production fighters (currently the first batch of 28 J-20's in active service)
|Program cost||US$4.4 billion|
The Chengdu J-20 (simplified Chinese: 歼-20; traditional Chinese: 殲-20) is a single-seat, twinjet, all-weather, stealth fifth-generation fighter aircraft developed by China's Chengdu Aerospace Corporation for the People's Liberation Army Air Force (PLAAF). The J-20 is designed as an air superiority fighter with precision strike capability; it descends from the J-XX program of the 1990s.
The J-20 made its maiden flight on 11 January 2011, and was officially revealed at the 2016 China International Aviation & Aerospace Exhibition. The aircraft was in military service by March 2017, with the aircraft officially entering combat training phase in September 2017. Combat units began inducting the aircraft in February 2018.
The J-20 is the world's third operational fifth-generation stealth fighter aircraft, and the first in Asia. The PLA jet classification system categorizes the J-20 as fourth-generation aircraft, following the Chengdu J-5, Chengdu J-7 and Chengdu J-10; the PLA aircraft generations are based on when the aircraft is integrated into the force and stealth fighters in 21th century are considered fourth-generation.
The J-XX (Chengdu J-20) development program was started in the late 1990s. A proposal from Chengdu Aerospace Corporation, designated Project 718, won the PLAAF endorsement following a 2008 competition against a Shenyang proposal that was larger than the J-20.
In 2009, a senior PLAAF official revealed that the first flight was expected in 2010–11, with a service entry date by 2019. On 22 December 2010, the first J-20 prototype underwent high speed taxiing tests outside the Chengdu Aircraft Design Institute. Three months later, the first J-20 prototype made its maiden flight in Chengdu.
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-guide munition, and six additional passive infrared sensors can also be spotted around the aircraft. In December 2015, the Low rate initial production (LRIP) version of J-20 had been spotted by a military observer.
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 combat-ready.
The J-20 has a long and wide 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 round engine exhausts.
One important design criterion for the J-20 is high instability. 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. 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.
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.
Official information on radar type that the J-20 will use has not been released to the public. Some analysts believed that J-20 will use Type 1475 (KLJ-5) active electronically scanned array (AESA) radar with 1856 transmit/receive modules, but more recent informations revealed that this radar is designed for upgraded versions of J-11D. Other analysts point out that based on J-20 nose cross section, using known data about a single transmit/receive module surface in J-16's AESA radar, J-20 have space for radar that fits 2000-2200 transmit/receive modules.
Prototypes after application "2011" and production models feature revised nose section with 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 combing radar signal with IR image in order to provide better situational awareness. One is located in front of the cockpit, a second one aft of the cockpit. The combination of an integrated targeting pod with spherically situated passive-optical tracking system is reported similar to the design concept of Lockheed Martin F-35's avionic suite. 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.
The aircraft features a glass cockpit, with two main large color liquid crystal displays (LCD) touchscreen situated side-by-side, three smaller auxiliary displays, and a wide-angle holographic head-up display (HUD). A Helmet-mounted display system also presented at Zhuhai Airshow. The helmet is able to provide aiming assistance and help pilot to utilize battle management information more efficiently from other part of the airborne system.
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). The lateral bays allow closure of the bay doors prior to firing the missile, thus enhancing stealth. The fighter is able to carry four medium/long range AAMs in main bay and one short-range missile one in each lateral weapon bay of the aircraft.  A staggered arrangement with six PL-15s may be possible depending on the missile launchers mounted in the future.
While the figher typically carries weapons internally, the wings include four hardpoints to extend ferrying range by carrying auxiliary fuel tanks. 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.
Three types of engines will be used to test the capacity of J-20 in the development stage. The prototype is believed to be initially powered by WS-10 and / or the AL-31F engines. China is currently working on an advanced domestic turbofan engine similar in performance to the Pratt & Whitney F119 coded WS-15 to take the J-20 to a higher performance level in the future like the ability to supercruise, but there are also speculations that 117S engine may be used for the initial batch of the J-20. At the 2012 Zhuhai Air Show, Russia approached China in an unsuccessful bid to sell the Su-35, which included the 117S engines. According to the latest news, China and Russia signed a contract for 24 Su-35 in November, 2015. However, Chinese source stated that the design of J-20 is mature and it will not directly use 117S engine.
The LRIP model is equipped with two WS-10B engines, an improved model based on the engine equipped on J-10, with plans in future to use WS-15 engine. The future production version of the J-20 is believed to be powered by the WS-15, a turbofan engine currently under development. 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 Air Show.
Analysts noted that the J-20's nose and canopy use a 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. One prototype has been powered by WS-10G engines equipped with different jagged-edge nozzles and tiles for greater stealth.
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. 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. 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. McDonnell Douglas and NASA's X-36 featured canards and was considered to be extremely stealthy. Radar cross-section can be further reduced by controlling canard deflection through flight control software, as is done on the Eurofighter.
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.
In May, 2018, Indian Air Chief Marshal B.S. Dhanoa claimed that Su-30MKI fighters could detect J-20 from "several kilometers away" amid reports from Indian medias that J-20 is undetectable. Analyst Justin Bronk from Royal United Services Institute noted that Chinese are possibly flying the J-20 with radar reflectors during peace time for safety and training purposes, which stealth aircraft often fly with markers that destroy their stealth during peacetime maneuvers.
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. 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. On 17 April 2011, a second test flight of an hour and 20 minutes took place. On 5 May 2011, a 55-minute test flight was held that included retraction of the landing gear.
On 26 February 2012, a J-20 performed various low-altitude maneuvers. On 10 May 2012, a second prototype underwent high speed taxiing tests, and flight testing that began later that month. 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.
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. 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 the "2014" and "2015" prototypes, the J-20's fuselage contains more of engine's surface area inside the stealthy fuselage, providing greater rear-facing stealth against enemy radar.
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. It has been reported that the design of J-20 is already mature and will not directly use the 117S engine.
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.
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). Initially, the lack of a suitable indigenously produced engine hindered the mass production of the J-20, however in September of 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.
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. On 9 March 2017, Chinese officials confirmed that the J-20 had entered service in the Chinese air force.
The J-20 officially entered service in September 2017 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.
The PLAAF began inducting J-20s into combat units in February 2018.
Pilot training for the J-20 started as early as March 2017, after the fighter entered limited service in the initial operational capability phase. Training with mixed generations allow pilots to become familiar with fifth-generation aircraft, and to develop tactics both for and against them. During the IOC phase, the fighters are equipped with radar reflectors, also known as Luneburg lens to enlarge and conceal the actual radar cross section. 
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. Training with mixed generations allow pilots to become familiar with fifth-generation aircraft, and to develop tactics both for and against them. Chinese Ministry of National Defense also revealed that J-20 has conducted night confrontation missions during several coordinated tactical training exercises.
The J-20 participated in its first over-ocean combat exercise in May 2018. The PLAAF is also developing Shenyang FC-31. The J-20 is slightly faster, with a maximum speed of Mach 2.5 compared to Mach 2 for the FC-31.
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 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 there had been a pre-planned test." Hu seemed surprised by Gates' inquiry, prompting speculations that the test might have been a signal sent unilaterally by the Chinese military. 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.
According to Asia Times, China is rumored to be considering the sharing of J-20 technology with allies such as Pakistan, with the backdrop of Pakistan's long-standing feud with India and poor relations between China and India over such issues as the Doklam Plateau border dispute serving as a possible motive.
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." 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.
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. 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." 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.
Observers were not able to reach a consensus on J-20's primary role. 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. 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 could threaten vulnerable tankers and ISR/C2 platforms, depriving Washington of radar coverage and strike range. 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.
A 2015 RAND Corporation report noted the J-20’s combination of forward stealth and long range could hold U.S. Navy surface assets at risk, and that a long-range maritime strike capability may be a cause for greater concern than a short-range air-superiority fighter like the F-22. After the deployment announcement, several analysts noted that future experiences the PLAAF is going to have with the J-20 will let China leverage a significant edge over India, Japan and South Korea, which struggle to design and produce their own fifth-generation fighters program by schedule.
In April 2009, a Wall Street Journal report 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.
Aircraft of comparable role, configuration and era
China plans to have at least 500 to 700 J-20 fighter jet before 2035 to challenge USA's F-35.
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