Shenyang FC-31

The prototype conducted a high-speed taxiing test and briefly became airborne. On 31 October 2012, prototype No. 31001 conducted the model's maiden flight.[1][3][19][20][21] It was accompanied by two J-11 fighters in a ten-minute test flight with its landing gear lowered.

With the maiden test flight of the prototype No.31001 on 30 October 2012, China became the second nation after the 1991 Advanced Tactical Fighter fly off, to have two stealth fighter designs in field-testing at the same time.[19][20] The aircraft has continued a limited test program, with footage emerging of further flights which took place in February 2013.[22]

A ​¹⁄₄-scale model of the J-31 was shown at the China International Aviation & Aerospace Exhibition 2012, hinting at a desire to offer the aircraft for export, as an alternative for those countries that cannot purchase the F-35.[23]

The J-31 airframe was publicly unveiled on November 12, 2014 at Zhuhai Airshow.[24][25] In TV broadcast of the unveiling, AVIC chairman Lin Zuoming claimed that funding for the aircraft came entirely from the company, with no input from military.[26]

As typical in flight displays of fighter jets, afterburners were engaged throughout the maneuvers. Nevertheless, Reuben Johnson of ainonline.com claimed it to be evidence of aerodynamic inefficiencies, concluding that the aircraft "bleeds a lot of energy and the pilot had a hard time keeping the nose up."[27] Flights were done when the jet was "clean," so results would be worse when fitted with a combat loadout. However, a large-scale model of the FC-31 on display did show some detail changes of configuration compared to the flying prototype.[27]

At the 2015 Dubai Airshow, AVIC released more details regarding the aircraft's capabilities. The company revealed it is still looking for a partner in the aircraft project, and is actively marketing the aircraft to People's Liberation Army Air Force. AVIC's plan was to have a production model first flight by 2019.[28][29]

It is very likely that the J-31 will be inducted as a carrier-based naval fighter. In an interview with China's state-run media, the J-31's chief designer Sun Cong expressed that the aircraft would follow his J-15 onto China's aircraft carriers.[30] However, officials from AVIC only said that the aircraft was intended for export as a competitor to the F-35.[31][32][33][34] There has also been reports that the PLAAN has urged Shenyang to develop a carrier-compatible version of J-31.[35]

In 2015, Jiangsu A-Star Aviation Industries Company marketed its EOTS-86 infra-red search and track as a possible addition to the J-31.[36] An improved prototype, with modifications to the vertical stabilizers, wings, and airframe, an electro-optical targeting system, a larger payload, improvements in stealth, and upgraded electronics, made its maiden flight in December 2016.[4][37]

In November 2018, an Aviation Week article stated that the FC-31 program has received government funding and is being sought after by both the PLANAF and PLAAF, according to official sources.[38] In June 2020, reports surfaced that a third variant of FC-31, albeit a more production-ready version with smoother lines, bigger radome for bigger radar, and a closer alignment of control surfaces for reduce radar signature, has been developed.[35] The "new fighter' has been referred to by some as J-35.[39]

The J-31 is smaller than the Chengdu J-20. The use of twin-wheel nose landing gear led to speculations that the J-31 may have been intended to be a carrier based fighter.[40][41][42] Bill Sweetman has cited several improvements to the F-35C design files the Chinese may have acquired in the J-31.[43] Analyst David Bignell argues that J-31 is rather based on F-22, due to the similarity in platform, shape, aerodynamics and airframe configuration, instead of F-35.[44]

The J-31 has two internal weapons bays that can each carry two medium-range missiles, along with two heavy hardpoints and one light hardpoint on each wing, but while it seems to have added an additional light hardpoint to each wing over the capacity of the F-35, it seems to lack the capacity of the F-35 to mount a centerline gunnery or jamming pod.

Officials from AVIC claimed that additive manufacturing was extensively used on the aircraft, resulting in 50% reduction in components compared to similar aircraft. However, the resulting airframe cannot be disassembled, and the static test frame had to be transported in whole as a consequence.[26]

According to Vladimir Barkovsky of Russian Aircraft Corporation MiG (formerly known as the Mikoyan-Gurevich Design Bureau), the engines on the prototype aircraft are RD-93s.[16][45] However, China already has an engine similar to the RD-93, the Guizhou WS-13 currently installed on the JF-17 which has the same thrust and size of the Russian RD-93. China is working on an improved variant named WS-13E with 100 kN (22,000 lb_f) of thrust for use on the J-31. Lin Zuoming, chairman of China's AVIC, has said that he hopes to put domestic engines on the fighter.[46] As the Chinese build up confidence in newer, more reliable and powerful domestic engines, they may be able to power the J-31 sooner than the larger J-20 and in greater numbers.[47]

The J-31 can carry 8,000 kg (18,000 lb) of payload, with four munitions totaling 2,000 kg (4,400 lb) internally, and 6,000 kg (13,000 lb) carried on six external hardpoints; primary armaments include the PL-10 short-range missile and PL-12 medium-range air-to-air missile. 4 PL-21 missiles can also be fitted inside the J-31's internal weapons bay.[48] It has a combat radius of 648 nmi (746 mi; 1,200 km) and a maximum take-off weight of 25,000 kg (55,000 lb).[28][29]

The J-31 is speculated to use stealth coatings instead of "baked in" fiber-mat stealth.[49] Officials from AVIC claim the aircraft to be stealthy against L-band and Ku-band radars, and would be low-observable against a number of multi-spectrum sensors.[28] The engine nozzles are apparently being redesigned to reduce radar and infrared signatures.[50]

The maximum take-off weight of this J-31 increased from 25,000 kg to 28,000 kg.[51]

Shenyang Aircraft Corporation has officially confirmed that J-31 is installing WS-19 engine, which has a maximum thrust of 12 tons, compared to WS-13 whose thrust is 9 tons.[51] The total thrust of the jet has been increased from 18 tons to 24 tons. The maximum range of this jet was also extended to 1250 km.[51] It can also cruise at supersonic speed.[51]

The J-31 is now using stealth coatings instead of "baked in" fiber-mat stealth.