J-20 ‘Mighty Dragon’ Optimised For Air Dominance

Within 24 hours of India and Russia inking a preliminary design contract (PDC) for the joint development of the twin-engined, tandem-seat 17.2-tonne Fifth Generation Fighter Aircraft (now called Perspective Multi-role Fighter), China’s Chengdu Aircraft Industries Corp (CAC) on December 22 last year rolled out the first (No2001) of two flying prototypes of its fifth-generation single-seat J-20 ‘Mighty Dragon’ 23-tonne air dominance multi-role combat aircraft. Subsequently, high-speed taxi trials of this prototype got underway, and its maiden flight, lasting 20 minutes, took place on January 11 at 12.50pm. Under development since 1998, the JXX, to be known as the Jian J-20 once it enters service by 2017, has been jointly designed by the CAC’s Chengdu Aircraft Design Institute No611 and Shenyang Aircraft Corp’s 601 Institute. The Shenyang Aero-Engine Research Institute, or Institute 606, was tasked in 1998 with developing the JXX’s 18,350kg-thrust (180kN) Woshan WS-15/Qinling-2 turbofan and its thrust-vectoring nozzles. J-20 No2001, though, is powered by twin WS-10G Taihang turbofans (each rated at 135kN and equipped with FADEC controls), since the WS-15 will not be available until 2012. The WS-10G has been developed by Guizhou-based Honglin Group (AVIC's Factory No143). The J-20 is next scheduled to go from Chengdu to the China Flight Test Establishment (CFTE) at Yanliang, which is located northeast of Xian in central China’s Shaanxi province. There, the two J-20 prototypes will undergo several phases of flight-tests and systems integration refinements, a process which will last until 2014. Following this, the first batch of up to eight CAC-built limited series production J-20s will be deployed first to the PLAAF’s Dingxin air base, located in north-central China near the Shuangchengzi missile test range, for weapons qualification trials, and then to the PLAAF-owned Flight Test & Training Centre (FTTC) at Cangzhou air base south of Beijing, where service induction procedures will be tried, applied and finalised. Following this, the PLAAF is expected, by late 2017, to form a J-20 operational conversion unit at Jiugucheng air base with up to 16 J-20s.

The existence of the J-20 was first announced in a November 2009 interview on Chinese CCTV by Lt Gen He Weirong, deputy commander of the People’s Liberation Army Air Force (PLAAF). He had then said that a ‘fourth-generation’ combat aircraft would be flown in late 2010 and become operational between 2017 and 2019. Work on fabricating the first of two J-20 flying prototypes got underway in late 2007 at CAC’s No132 Aircraft Plant and a year later a full-scale mock-up was available for airframe fatigue-testing purpose. The J-20 has been designed to have a 0.05 square-metre radar cross-section (head-on), and its airframe features a large dihedral canard-delta wing configuration, with a pair of outward/rearward canted all-moving combined vertical/horizontal tails and similarly large, outward canted ventral fins/strakes which, if all-moving like the tails, will make for some quite advanced capability options in the areas of controllability and manoeuvrability. The flat body sides are aligned with the canted tails, the wing-body junction is clean, and there is a sharp chine line around the forward fuselage. The stealth shaping is without doubt considerably better than that seen in the two Sukhoi OKB-designed T-50 PAK-FA multi-role combat aircraft (MRCA) prototypes, and even more so, than that seen in the Lockheed Martin F-35 Joint Strike Fighter (JSF). The design appears to be largely built around the stealth shaping design rules employed in the Lockheed Martin F/A-22A Raptor. Takeoff weight is estimated to be 80,000lb without any weapons payload. The fuselage length is 21.5 metres, wingspan is 13.8 metres, height is 5 metres, and the weapon’s bay’s length is 6.52 metres. The chined nose section and frameless canopy bear a close resemblance to those of the F/A-22A, as do the trapezoidal edge aligned engine inlets, though they appear to be larger and employ a diverterless supersonic inlet design, obviously intended to reduce inlet edge signature. The J-20’s wing-fuselage join, critical for beam and all-aspect stealth, is both in shaping and angle very similar to that of the F/A-22A, and clearly superior to those on the T-50 PAK-FA and F-35 JSF. The flat lower fuselage and planform alignment is optimal for all aspect wideband stealth, and closely emulates the F/A-22A’s design. The nose and main undercarriage doors employ X-band optimised edge-serration technology similar to that on board the F-117A Nighthawk and F/A-22A. The main landing gears retract into body-side bays, indicating the likely presence side weapon bays ahead of them. The ground clearance is appreciably higher, which would facilitate loading precision-guided air-to-surface munitions. Features at the rear of the aircraft—including underwing actuator fairings, aft fuselage tailbooms, fins/strakes, axisymmetrical engine exhausts and the ventral fins—appear less compatible with stealth. The airframe configuration and aft fuselage shape is compatible with both thrust vector control (TVC) nozzle design, or a non-TVC rectangular nozzle designed for controlled infra-red emission patterns and radio-frequency stealth. The airframe configuration is compatible with ventral and side opening internal weapon bays, and large enough to match or exceed, by some degree, the internal weapons payload of the F/A-22A. Internal fuel capacity is also likely to be high, given the fuselage configuration and large internal volume of the big delta wing. This indicates an intent to provide a sustained supersonic cruise capability. There is also provision for an aerial refueling probe portside below the cockpit canopy.

Guided-weapons to be carried internally by the J-20 on four separate weapons bays include up to eight 16km-range PL-10 within-visual-range air combat missiles or 100km-range PL-21 ramjet-powered beyond-visual-range air combat missiles (jointly developed by CPMIEC and Leihua Electronic Technology Research Institute), along with the FT family of GPS-guided small-diameter bombs, especially the FT-6, which comes equipped with twin glide wings. The PL-21 will incorporate an on-board two-way data link to expand the missile’s engagement envelope and support the increased HOBS capability. It will allow a third party, such as another combat aircraft or an AEW & C platform, to take control of the missile, allowing the firing aircraft to break away directly after launch. Two-way data links have the potential to increase weapon effectiveness during long-range engagements, since they could allow the missile to pass information on target characteristics and target behaviour to the launch platform as the engagement proceeds. Both the PL-10 and PL-21 will house a sub-millimetre wave-imaging fuze operating at frequencies above 200GHz to detect and classify the target aircraft and select the aimpoint for the ‘mass-focussed’ warhead to make sure more fragments hit their mark.

The integrated avionics suite will be of the open architecture-type and use the MIL-STD-1553B databus. The suite will incorporate features like automated data fusion, emission control and low-probability-of-intercept data links to build an operational picture for the pilot without giving away the aircraft’s own location. Elements of the suite will include an active phased-array multi-mode radar now being developed by the China Electronics Technology Group Corp’s (CETC) Nanjing Research Institute for Electronic Technology (NRIET, also known as the No14 Research Institute); retractable Hongguang-2 imaging infra-red search-and-track sensor (that includes a HgCdTe focal array with imaging infra-red capability) with 75km-range developed by Sichuan Changhong Electric Appliance Corp; Xian-based Cigong Group’s holographic heads-up display and helmet-mounted display (the latter being a copy of the ZSh-7APN Sura-K HMD designed by the Arsenal Central Design Bureau State Enterprise of Ukraine); optronic missile approach warning-cum-countermeasures dispensing system developed by the Luoyang Optical-Electronic Technology Development Centre; and a quadruplex fly-by-wire flight control system, integrated communications suite, defensive aids sub-systems, low probability of intercept IFF transponder, TACAN, and an all-glass cockpit, all developed by the Suzhou-based AVIC Radar and Avionics Equipment Research Institute and the China Leihua Electronic Technology Institute (CLETRI, also known as the 607^th Institute). The J-20’s all-glass cockpit will feature twin ruggedised 8-inch by 20-inch panoramic active-matrix liquid crystal displays (PAMLCD) with both intuitive touch-screen and direct voice input usage, plus four smaller AMLCDs. The PAMLCD is an open system architecture-compatible dual redundant display that presents crisp, clear high-fidelity graphics and video overlays with a revolutionary infra-red touch screen human machine interface. A substantial portion of the J-20’s avionics LRUs were developed in cooperation with Ukraine’s Special Radio Device Design Bureau, Topaz Company, the Donetsk National Technical University, and SKB RTU. The internally-mounted directional jamming system, using active phased-array T/R modules, is being jointly developed by Southwest China Research Institute of Electronic Equipment, and the No51 Research Institute, which is also known as the Shanghai Research Institute of Microwave Equipment (SRIME). The same consortium is also developing the J-20’s ADF and VOL/ILS receivers.— Prasun K. Sengupta