Shenyang J-31

The Shenyang J-31, rumored to be nicknamed "Gyrfalcon" (鹘鹰), or Falcon Hawk by some military enthusiasts, is a twin-engine, mid-size fifth-generation jet fighter currently under development by Shenyang Aircraft Corporation. The fighter has also been referred to as F-60 or J-21 Snowy Owl (雪鸮) in media reports.

Development
A photo of a model labeled F-60 was posted on the Internet in September 2011. In June 2012, photos and camera video clips started to emerge on internet about a heavily overwrapped possible F-60 prototype being road-transferred on a highway, earning the nickname "the zongzi plane" (粽子机) among Chinese netizens, though some suspect it of mere being a L-15 trainer aircraft. Pictures of a possibly fully assembled aircraft parking on an airfield emerged on September 15–16, 2012. The F-60 is reported to be the export version, where the J-31 would be the domestic Chinese version of the same fighter.

Strategic implications
The appearance of the J-31 raised concern about a potential arms race in Asia, as some of China's neighbors might again start to consider purchasing the F-35.

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. AVIC confirmed at the exhibition that the aircraft was intended for export. In 2013 Admiral Zhang Zhaozhong confirmed that the J-31 was only for export to countries unable to buy the F-35 and would not be used by the PLAN. Stephen Biddle of the Council for Foreign Relations has speculated that the aircraft design was intended for domestic use, but found to be under performing and hence relegated to the export market.

Flight testing
The prototype conducted a high-speed taxiing and briefly became airborne. On 31 October 2012, prototype No. 31001 conducted the model's maiden flight. 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 October 31, 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. The aircraft has continued a limited test program, with footage emerging of further flights which took place in February 2013.

Design
The J-31 is a mid-weight, twin rudder and twin-engine jet with the typical configuration that is commonly shared by other 5th generation fighters such as Sukhoi T-50. J-31 incorporates certain stealth characters such as forward swept intake cowls with diverterless supersonic inlet (DSI) bumps and a two-piece canopy.

The J-31 appears to be a smaller and more agile aircraft than the Chengdu J-20 that resembles a twin engine F-35C. This may be because it might be used as a fifth generation carrier based fighter. Another feature that the J-31 shares with the F-35C (and most other carrier based fighter jets) is the twin forward wheels. Bill Sweetman has cited several improvements to the F-35C design files the Chinese may have acquired in the J-31. Like the F-35, 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 very 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.

The J-31's chief designer, Sun Cong, has said that he hoped that the aircraft would follow his J-15 onto China's aircraft carriers.

It is unknown if the J-31 is meant to be a competitor to the J-20 stealth fighter or a complement to it. It is also unknown if it will be a land-based fighter for the People's Liberation Army Air Force, or a carrier-based fighter for the People's Liberation Army Naval Air Force on the Liaoning Aircraft Carrier and future Chinese carriers.

Vladimir Barkovsky of Russian Aircraft Corporation MiG (formerly known as the Mikoyan-Gurevich Design Bureau) has stated that, despite some design flaws, the J-31 "looks like a good machine." Although it contains features already in use on the U.S. fifth generation fighter designs, it is "not a copy but a well done indigenous design." Barkovsky has confirmed that the engines on the prototype aircraft are RD-93s. 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-13G with 100KN 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.

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.

USAF Lieutenant General Charles Davis has said that while the Chinese fifth generation fighter may have used stolen information from the F-35 program, they were unlikely to measure up to the American aircraft.

Unlike the F-35's "baked in" fiber-mat stealth, the J-31 uses stealth coatings.

Specifications (estimated)
Because the aircraft is in development, these specifications — based on available imagery — are approximate and preliminary.