China’s much-debated J-20 stealth fighter has now entered the low-rate initial production (LRIP) phase. Following on from two prototype/technology demonstrators and at least six pre-production development aircraft, the first of a new batch of production examples made an appearance outside Chengdu’s works in late December. It reportedly made its first flight on January 18, by which time a second LRIP aircraft had also been spotted at the airfield.

Whereas the earlier aircraft had all been numbered in the 20xx range, and were revealed in a full painted finish, aircraft 2101 was seen undergoing taxi trials in December in a yellow primer finish typical of aircraft fresh from Chengdu’s production lines. A second LRIP machine, 2102, was recorded in January, also in the primer finish.

Designed by the 611 Institute and built by the Chengdu Aerospace Corporation at the Huangtianba airfield, the J-20 is a large multi-role fighter with stealthy features similar to those found in the American F-22 and F-35. Although very little is known about its intended purpose, the aircraft appears to offer capability in a number of roles, including long-range interception and precision attack.

In terms of weapon carriage the J-20 has a similar arrangement to that of the Lockheed Martin F-22, comprising two lateral bays for small air-to-air missiles such as the agile, imaging-infrared PL-10, and a large under-fuselage bay for accommodating larger missiles and precision-guided surface attack weapons. The 607 Institute’s new PL-15 active-radar missile is thought to be the primary long-range air-to-air weapon, reportedly having been test-fired from a Shenyang J-16 platform last year. The PL-21, a ramjet-powered weapon in the same class as the MBDA Meteor, is another possibility for the J-20.

The sensor suite includes an electro-optical targeting system (EOTS) and a large-array AESA radar, which was developed by the 14th Institute at Nanjing Research Institute of Electronics Technology (NRIET, 14th Institute), and is possibly designated Type 1475/KLJ-5. Diamond-shaped windows around the fuselage suggest that a distributed aperture infrared vision system is installed.

In the cockpit, the J-20 sports three large color displays, plus other small screens, and a holographic wide-angle head-up display. An advanced datalink has been developed, and a retractable refueling probe is located on the starboard side of the forward fuselage. Much of the avionics suite has been tested by the CFTE (China flight test establishment) aboard a modified Tupolev Tu-204C, in much the same way as the systems of the F-22 were tested in a Boeing 757.

One area that has dogged the J-20 is the powerplant, where Chinese indigenous development has lagged behind that of the airframe and systems. The intended powerplant for the J-20 is believed to be the WS-15, an afterburning engine in the 44,000-pound-thrust (197-kN) class being developed by Xian, and which may ultimately feature thrust-vectoring. However, this engine is not expected to be ready until around 2020. In the meantime, the J-20s produced so far have been powered by the NPO Saturn AL-31FN (as used in the single-engine J-10) imported from Russia. The latest J-20s have the improved AL-31FN Series 3 engine offering 30,800 pounds (137 kN) of thrust, but even this engine may not provide the J-20 with “supercruise” capability.

J-20 History

Spurred on by developments in both indigenous technology and U.S. military capability, China initiated a project for a twin-engine stealthy fighter in the early/mid-1990s, subsequently reported by U.S. intelligence as the XXJ program. Chengdu/611 Institute’s Project 718 competed with a larger design from Shenyang/601 Institute, and was eventually selected in 2008.

Chengdu is believed to have built an initial batch of four prototype airframes, of which two took to the air. The first, 2001, made its maiden flight on January 11, 2011. It was followed on May 16, 2012 by aircraft 2002, which was subsequently renumbered as 2004. Two other airframes are understood to have been used for ground static and fatigue testing, and additional airframes may have later been produced for radar cross-section tests.

On March 1, 2014 the first of the development batch aircraft (2011) made its first flight. Whereas 2001 and 2002 appeared to be prototypes for evaluating aerodynamics and aircraft systems, as well as limited weapon carriage tests, aircraft 2011 was clearly outfitted for some mission systems.

Quite apart from the new RAM (radar-absorbent material) paint, there were numerous differences between it and its predecessors: the tailfins featured cropped tips; the inlets and DSI (diverterless supersonic intake) bulges had been redesigned; the leading-edge root extensions between wing and foreplanes were reshaped; the canopy had gained a stiffening bow frame; and the cumbersome main-wheel door design of the initial aircraft had been replaced by a much neater installation.

Perhaps the most obvious differences were the new nose design with a dielectric radome for an AESA radar featuring a sawtooth joint with the main fuselage, and the addition of an electro-optical targeting system in a fairing beneath the forward fuselage.

Three further development aircraft took to the air during 2014;Number 2012 on July 26; Number 2013 on November 29; and Number 2015 less than a month later on December 19. The latter two lacked a nose-mounted air-data probe, suggesting that the AESA radar was installed. Aircraft Number 2016 flew on September 8, 2015 with reshaped DSI bulges and lengthened fairings around the nozzles to improve rear-aspect radar cross-section. Other changes included enlarged fairings to either side of the engine nozzles. Aircraft 2017 followed on November 24, with a slightly more pronounced hump to the canopy.

At least four aircraft of the development batch were transferred to the CFTE (China flight test establishment) at Xian-Yanliang for tests. It is expected that the initial LRIP aircraft will be dispatched to the Chinese air force’s test and training center at Cangzhou once initial manufacturer/acceptance trials have been completed, and during 2017 the first front-line regiment could start to receive aircraft. IOC is slated for 2019, but may occur earlier given the priority afforded to the J-20 program. Chinese officials have stated that final requirements could be between 500 and 700 aircraft.