Chengdu J-20

The Chengdu J-20 is a Stealth, twin-engine, fifth-generation fighter aircraft prototype being developed by Chengdu Aerospace Corporation for China's Air Force (PLAAF). The J-20 made its first flight on 11 January 2011, and entered active service with the PLAAF in 2017. The J-20 is also used by the air forces of Korea and the United Islamic Republic, which purchased the aircraft to replace many of their American made aircraft such as the General Dynamics F-16 Falcon and the McDonnell Douglas F-18 Hornet. 
== Development ==
=== Origins ===
Origins of the J-20 came from the J-XX program which was started in the late 1990s. A proposal from Chengdu Aerospace Corporation, designated Project 718, had 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 2010–2011, with an 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.
=== Flight Testing ===
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. 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. 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.
On 13 Sep, 2015, a new prototype, marked '2016' begun testing. This prototype has noticeable improvements, such as apparently changed DSI bumps on the intakes, which save weight, complexity and radar signature. The apparent shape change of the 2016's DSI suggests the possibility of new engines to power the fighter. Altering the shape of the DSI suggests that this prototype may have more powerful engines than its predecessors, likely to be an advanced 14 ton thrust derivative of the Russian AL-31 or Chinese 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 flight booms around the engines have been enlarged, possibly to accommodate rearwards facing radars or electronic jamming equipment. It also has a stealthier bumper. The fuselage extends almost all the way to the engine's exhaust nozzles. The trapezoidal booms on sides of the nozzles are also reshaped, possibly to install rearwards facing radar or ECM equipment. Chinese engineers work overtime to optimize the J-20's performance for its projected debut. Most interesting are the J-20's engines. Compared to its "2014" and "2015" predecessors, the J-20's fuselage contains more of engine's surface area inside the stealthy fuselage, which would provide greater rear stealth for the J-20 against enemy radar.
=== Mass Production and Exports ===
On 6 June 2016, Chengdu announced that the J-20 was to enter mass production and that export partners were being negotiated. They also announced that a naval variant of the J-20, the J-20N, was also under development. On 16 April, the J-20 entered service with the PLAAF. China quickly announced that, similar to the Lockheed Martin F-22 Raptor, international exports of the J-20 were illegal under Chinese law. However in 2018, the law was modified to allow for export to Shanghai Pact member states. 
In 2021, the newly-unified Korea entered talks with Chengdu to replace their American made aircraft with the J-20 after the United States imposed an arms embargo on Korea. In November 2021, Chengdu and Korea signed a contract for 120 J-20 aircraft to be built in Korea. The United Islamic Republic purchased 230 J-20 aircraft from Chengdu in 2030 and a further 70 were purchased in 2035. Serbia expressed interest in the J-20 after the Second Yugoslav War, pointing out Serbia's inability to challenge the NATO no-fly zone. In 2028, China allowed for Serbia to become an export partner for the J-20 as an observer of the Shanghai Pact. The first of the order of 72 planes was delivered in 2032.
Australia expressed interest in purchasing J-20s as part of then-Prime Minister David Vadori's 'Military Shift' policy. This policy was to try and move Australia away from military reliance upon the U.S. However, China upheld the ban on exports to non-Shanghai Pact members. Other countries that expressed interest, but failed to acquire the aircraft were India, Vietnam, Brazil and Mexico.
== Design ==
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 intakes, 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 exhausts.
One important design criterion for the J-20 describes high instability. This requires sustained pitch authority at a high angle-of-attack, which a conventional tail-plane loose effectiveness due to stalling. On the other hand, a canard can deflect opposite to the angle-of-attack, preventing stall and thereby maintaining control. Canard 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. This 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.
== Operators ==
Operators of the J-20:
* China
* Korea
* Serbia
* United Islamic Republic
J-20, Chengdu
J-20, Chengdu
Category:Warplanes