The next generation carrier-based stealth fighter was rumored to be under development at the 611 Institute (based on J-20?). First flight is expected between 2013 and 2014. It is expected to compete with the smaller J-21 (navalized) from the 601 Institute.
J-20 Mighty Dragon
The J-20 (K/JJ20?) #2001 prototype/technology demonstrator made its maiden flight on January 11, 2011 over the city of Chengdu, wearing a distinctive dark green color scheme and powered by two indigenous WS-10X turbofan engines. The prototype features a pair of all-moving tailfins and Russian 1.44 style twin ventral stabilizing fins and tail booms, which shield the engine nozzles and its heat exhausts but might increase RCS. Also there are four large underwing actuator fairings which might not be stealth optimized. It also features an F-22 style forward fuselage, including adjustable Caret inlets but with DSI bumps installed at the upper inner corners, as well as a one-piece frameless canopy. Small LERX are installed between the canards and main wings in order to generate vortex together with the canards at high AoA. Two small dark diamond shaped windows can be seen on both sides of the nose, which could house certain EO sensors, such as MAWS. Two additional windows are seen underneath the rear fuselage, plus two more located forward and aft the cockpit, suggesting a distributed situational awareness system similar to the EODAS onboard American F-35 was installed providing a full 360° coverage. Besides a large belly weapon bay for short/long-range AAMs (up to 6 PL-10, PL-12C/D or PL-15), two smaller lateral weapon bays have been identified behind the air inlets for short-range AAMs (1 PL-10 in each). The 2001 prototype appears to fly without an internal gun, which is expected to be installed onboard later ones. It also may be flying without the RAM coating applied but this may change later. First disclosed by US Office of Naval Intelligence (ONI) in 1997 as XXJ, J-20 (Project 718) is a 4th generation heavy air superiority fighter to enter the service with PLAAF between 2016 and 2018, a time frame much faster than the one (>2020) anticipated by the western military analysts. Since early 90s both CAC/611 Institute and SAC/601 Institute had been working their own designs to bid for a twin-engine heavy fighter with stealth capability and maneuverability comparable to American F-22. It was speculated that 601 Institute was working on a "tri-plane" design based on canard/conventional layout/V-shape tailfin while 611 Institute working on a design based on canard/tailless delta wing/V-shape tailfin/lateral DSI/bump inlet layout. All designs would feature a belly internal weapon bay to reduce RCS, which has been speculated to be <0.05m2 (head-on). J-20 also incorporates an advanced FBW (or FBL?) system fully integrated with the fire-control and the engine systems. Its fire-control radar is expected to be AESA (Type 1475/KLJ5?) based on the less powerful model being tested onboard J-10B, both are developed by the 14th Institute. The radar is thought to be comparable to American APG-77. The next generation secure datalink is believed to be installed as well which provides secure networking with other J-20s and KJ-200/2000 AWACS. The aircraft also features a "pure" glass cockpit (three large color LCDs plus a few smaller ones and a wide-angle holographic HUD). Many of these subsystems have been tested onboard J-10B to speed up the development. The exact type of engine powering prototypes is unclear, even though a Chinese or Russian turbofan engine including AL-31F (AL-31F-M3? 15t class) and enhanced WS-10 (WS-10G?) (14t class) was speculated. In the end the Russian engine is believed to be the likely candidate. AL-31F features a new silver color "stealth" nozzle with saw tooth edges to reduce RCS and IR emission. However the nozzle has yet to demonstrate an axisymmetric TVC capability. It was reported in November 2006 that a 17-18t class T/W=9.5-10 turbofan (WS-15/"Large Thrust"/Emei?) with a TVC nozzle is being developed and will eventually power J-20s in production. J-20 appears slightly longer and slimmer than both F-22 and T-50, suggesting a compromise between achieving high speed/maneuverability and the less powerful engines available. Therefore currently the J-20 prototype still lacks the supercurise capability until the planned WS-15 turbofan enters the service. Russian assistance was also speculated in terms of software support for calculating the RCS and aerodynamics of various designs. The overall performance of J-20 is thought to be superior to that of Russian T-50 (maneuverability & supercruise) but still inferior to that of American F-22 (electronics & stealth). In August 2008 it was reported that 611 Institute was selected to be the main contractor for the development of J-20 and 601 Institute as the sub-contractor. Subsequently a full-scale metal mockup was built at CAC. One rumor in May 2010 claimed that 611 Institute started to construct the first prototype, which was expected to fly by the end of 2010, even though the full configuration version won't fly until a few years later. Two prototypes were constructed and the first low-speed taxi trial by 2001 took place on November 4, 2010. Once entering the service, J-20 could pose a significant impact/challenge to the air balance in eastern Asian and western Pacific region. The #2002 prototype made its maiden flight on May 16, 2012. There are a few minor external differences between the two prototypes. One is the pitot tube has been relocated to the nose tip. The other is the main landing gear doors remain closed while the gears are extended. #2002 also has a retractable IFR probe hidden beneath a cover on the starboard side of the cockpit similar to that onboard American F-35. A recent image (October 2012) suggested that #2002 prototype appears to have the AESA radar installed together with a new nose cone. Both #2001 and 2002 prototypes were sent to CFTE in Yanliang in 2012, suggesting the test program has moved to the next stage. The #2002 prototype was seen conducting weapon integration tests with a dummy PL-10 IIR guided short-range AAM on its retractable side missile launch rail in March 2013. Unlike that of F-22, the weapon bay door is closed while the missile is fully exposed to maintain low RCS and reduce drag during dogfight. Currently the third prototype (2003?) is thought to have been built and is preparing for its maiden flight. There were rumors that the 03 prototype will feature certain "major improvements" and is no longer considered as a "technology demonstrator". A tandem-seat trainer version (J-20S?) has been rumored to be in development as well but no details are available.
J-21/AMF Gyrfalcon
The J-21 (Project 310?) Falcon 01 prototype was approaching the SAC airfield after its successful maiden flight on October 31, 2012. A scale-down model (F-60) of J-21 was first unveiled by the 601 Institute at the first International UAV Innovation Grand Prix held in Beijing in September 2011. It was first rumored in April 2011 that 601/SAC has been developing a 4th generation medium multi-role stealth fighter as J-21 (Project 310) since 2007 after its own heavy stealth fighter design lost the bid to 611/CAC's J-20 (see above). The aircraft has a conventional design with twin engines and two large slanted trapezoidal tailfins similar to American F-22. As the result the ventral stabilizing fins are eliminated to save weight and reduce RCS. In addition it features DSIs, two piece canopy and a pentagon shaped nose similar to F-35. Like J-20, a retractable IFR proble could be installed on the starboard side slightly forward of the canopy. As a 4th generation fighter J-21 is expcted to be equipped with advanced avionics such as an AESA radar and a wide-angle holographic HUD. The prototype is expected initially to be powered by the 8.5t class RD-93/WS-13A turbofan (without TVC) but later by the new 9.5t class "Medium Thrust" engine (WS-13B, might feature 2D TVC). The RD-93 engine nozzles on the prototype appear without any stealth measures applied. However they are partially shielded by the two horizontal tailfins extending rearward, similar to F-35, thus reduces the IR and radar signatures. J-21 features a single internal weapon bay inside its belly housing up to 4 (?) AAMs including PL-10, PL-12 or PL-15. It may also be able to carry the larger YJ-83K AshM and YJ-91 ARM externally. However due to its relatively small size and lower engine thrust compared to J-20, J-21 might suffer from either a limited internal payload or a shorter combat radius. It is not expected to have the super-cruise capability initially either when powered by RD-93. Some specifications (speculated): length 16.9m, height 4.8m, wingspan 11.5m, normal TO wight 17.5t, combat radius 1,250km with internal fuel, max level speed Mach 1.8, TO distance 400m. A full-scale metal model was probably built in early 2011. One airframe was transported to the 623 Institute in Yanliang for static tests in June 2012. The first prototype was under construction since late 2011. Its first flight took place on October 31, 2012, powered by two smoky RD-93 turbofans. As a private venture of AVIC, J-21 (dubbed AMF/Advanced Multi-role Fighter) is expected to be promoted at the international market as a low-cost alternative to American F-35. Therefore it could have some negative impact on the prospects of FC-1/JF-17 in 7-10 years. Its first foreign customer is likely to be Pakistani AF. As for the domestic market, it appears to be a good candidate to replace all the remaining J-7E/G series light fighters still in service with PLAAF and PLAN, as the production of J-10 series will be limited to around 300. It was rumored that J-21 could compete with the other stealth fighter design from 611 Institute for the next generation PLAN carrier-based stealth fighter but this has not been confirmed. J-21 was partially unveiled at 2012 Zhuhai Airshow as an "advanced fighter concept", featuring a one-piece canopy.
