J-XX

J-XX J-X, and XXJ are names applied by Western intelligence sources to describe program(s) by the People's Republic of China to develop one or more fourth (by Chinese nomenclature) or fifth-generation fighter aircraft (by west). In a 2009 television interview, He Weirong (何为荣), deputy commander of the People's Liberation Army Air Force, stated that China had multiple such programs underway and that an as-yet-undesignated fifth-generation fighter developed jointly by Chengdu Aircraft Corporation and Shenyang Aircraft Corporation would be in service by 2017–2019. The maiden flight of the Chengdu J-20 stealth fighter was conducted on January 11, 2011.

History
In 2002, Jane's Defence Weekly reported that Shenyang Aircraft Corporation had been selected to head research and development of the new fighter, a claim repeated in New Scientist the same week. However, a 2006 article in Military Technology referred to three designs; two by Shenyang Aircraft Corporation and one by Chengdu Aircraft Corporation.

According to the report from Jane's, development of the subsystems, including the engine and weapon suite for the next generation fighter, has been under way for some time. A photograph of a wind tunnel model published with the article showed a twin-engine aircraft with twin vertical tail fins. The article text mentioned that the aircraft would carry its weapons internally like the F-22 Raptor. New Scientist called attention to the angular, faceted features of the design, comparing them to the F-117 Nighthawk. Jane's also linked the programme with China's development of an engine with thrust vectoring capability.

The later report in Military Technology featured a picture of a completely different design, speculatively dubbed J-14 and said to be a Shenyang project, with the designations J-12 and J-13 being applied to (possibly competing) designs by Shenyang and Chengdu respectively. Since 2009, Chinese internet comments have repeatedly pointed to a merging of the two efforts, to be named J-14. Chengdu is rumored to be responsible for the airframe, while Shenyang focuses on the engines and other components.

In November 2009 He Weirong (何为荣), deputy commander of the Chinese air force, confirmed that "intense" research and development work on the fifth generation stealth fighter was ongoing. Being developed by Chengdu Aircraft Corporation and Shenyang Aircraft Corporation, the aircraft has not yet been given a designation but is expected to be unveiled within the next 5 years and would enter service by 2015, according to Weirong. Another source quotes Weirong as saying the aircraft would enter service within 8 years, giving possible in-service dates of 2017 to 2019.

A U.S. Defense Intelligence Agency official commenting on Gen. He's claims stated the DIA believes a first flight of the J-XX "will occur in the next few years", but it is also believed that operational deployment of the fighter "in meaningful numbers" will not take place "for about 10 years." U.S. Air Force and U.S. intelligence officials have stated their belief that China likely has all the resources, data and technology required to build a fifth generation fighter. However, doubts remain on whether China has enough knowledge in areas such as systems engineering, integration and production processes to build a fighter comparable to U.S. stealth designs which can also be produced in large numbers. It is speculated that the fighter may not be an "all-aspect" stealth design by some sources, for this reason. The U.S. Department of Defense expects China to have a handful of fifth generation fighters in service between 2020 and 2025, according to statements made by U.S. Secretary of Defense Robert M. Gates in July 2009. However, a year later, in May 2010, this statement was rebuffed by the US' prime intelligence producer—Ulman stating that Chinese 5th generation fighter jets will be expected around 2018. In 2011 Gates changed his position to state that the Chinese may have 50 stealth fighters by 2020 and a couple of hundred by 2025 while the United States would have 850 and 1500 by those dates.

Western analysts have noted that while the Chengdu J-20 and Shenyang J-31 are expected to fall far short of the capabilities of the Lockheed Martin F-35 Lightning II, the delays in providing the American fifth generation fighter in sufficient numbers to American allies in the region may give China a window of opportunity over the legacy fighters of their neighbors.

In 2013, vice-president of the PLA Air Force Command Academy, Major General Zhu Heping noted manufacturing and innovation deficiencies as reasons for the slow rate of progress in developing jet fighters, especially in the area of engines. Military commentator Ma Dingsheng responded that these problems would take decades to overcome.

Design
The general design concept of the J-XX is that of a fifth-generation fighter which incorporates stealth, supercruise, super-maneuverability and short take-off capabilities, abbreviated "4S". One or more of the proposed designs are believed to incorporate several design features for increasing stealth and maneuverability while decreasing weight and drag.

The Chinese state television broadcaster China Central Television (CCTV) asserts:

A V-shaped pelikan tail could be implemented, replacing conventional vertical tail fins and horizontal stabiliser structures. This would be beneficial for reduction of radar signature, weight and aerodynamic drag, since control surface area and corresponding control mechanisms are reduced. Problems faced by this type of design are flight control system complexity and control surface loading. If the pelikan tail is adopted, use of engines with thrust vector control may alleviate these problems.

CCTV also asserts:

The new fighter may have a significantly longer fuselage than other fifth generation fighter designs, such as the F-22, for reduction of transonic and supersonic drag. A trapezoidal wing may be implemented for reduction of drag and radar signature. Use of an 's'-shaped air inlet and boundary layer separation system would greatly reduce radar signature.

A fifth generation fighter remains an ambitious goal for the PRC, because they are behind in the needed technologies such as aerospace-grade carbon fiber,  advanced fighter engines, and AESA radar.