Chengdu J-20

The Chengdu J-20 (simplified Chinese: 歼-20; traditional Chinese: 殲-20) is a stealth, twinjet, fifth-generation fighter aircraft prototype being developed by China’s Chengdu Aerospace Corporation for the Air Force (PLAAF). The J-20 made its first flight on 11 January 2011, and is expected to be operational in 2018.

China’s J-20 platform has the potential to be a capable, long-range strike system in the Asia-Pacific region, with low rate initial production appearing to have begun as of January 2016.

Prototype test plane no.2015 @cdn.media.worldjournal.com

Development

Origins

The J-XX program was started in the late 1990s. A proposal from Chengdu Aerospace Corporation, designated Project 718, won the PLAAF endorsement following a 2008 competition against a Shenyang proposal that was larger than the J-20.

In 2009, a senior PLAAF official revealed that the first flight was expected in 2010–11, with an service entry date by 2019.

On 22 December 2010, the first J-20 prototype underwent high speed taxiing tests outside the Chengdu Aircraft Design Institute.

“2101” is the first airframe in the inaugural production batch of J-20 fighters @nextbigfuture.com

China is flying the first airframe in the inaugural production batch of J-20 stealth fighters

The first J-20 squadron expected to be fully delivered by year’s end, the China Flight Testing Evaluation regiment will being developing operating procedures, tactics and technical proficiency to bring the J-20 to combat readiness. At this pace, it is expected that in 2017-2018, the Chinese Air Force will have its first operational stealth fighter squadron. Source nextbigfuture.com

More J-20 Stealth Fighters Built in China: Here

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Flight testing

J-20 flying display at Air show China 2016 in Zhuhai

On 11 January 2011, the J-20 made its first flight, lasting about 15 minutes, with a Chengdu J-10S serving as the chase aircraft. After the successful flight, a ceremony was held, attended by the pilot, Li Gang, Chief Designer Yang Wei and General Li Andong, Deputy-Director of General Armaments.

On 17 April 2011, a second test flight of an hour and 20 minutes took place. On 5 May 2011, a 55-minute test flight was held that included retraction of the landing gear.

On 26 February 2012, a J-20 performed various low-altitude maneuvers. On 10 May 2012, a second prototype underwent high speed taxiing tests, and flight testing that began later that month. On 20 October 2012, photographs of a new prototype emerged, featuring a different radome, which was speculated to house an AESA radar.

On March 2013, images of the side weapon bays appeared, including a missile launch rail.

Latest pictures of weapons bay

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J-20 with drop tanks

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On 16 January 2014, a J-20 prototype was revealed, showing a new intake and stealth coating, as well as redesigned vertical stabilizers, and an Electro-Optical Targeting System. This particular aircraft, numbered ‘2011’, performed its maiden flight on 1 March 2014 and is said to represent the initial pre-serial standard. Overall the year 2014 was quite a successful one and until the end of 2014 three more pre-serial prototypes were flown: number ‘2012’ on 26 July 2014, number ‘2013’ on 29 November 2014 and finally number ‘2015’ on 19 December 2014.

Third Prototype of China’s Stealth Jet Makes Maiden Flight and Shows Improvements

Composite image created with images from Xinhua News Agency, Chinese Internet (cjdby.net).

The third prototype of China’s 5th generation fighter jet made its maiden flight on Mar. 1.

As already explained, Beijing’s radar-evading plane shows several differences from the first (and second) prototype aircraft, a sign China is improving and developing more in the field of low observability applied to fighter jets.

These are, an overall light grey color scheme similar to that of U.S. stealth planes (most probably a radar-absorbing coating); new air intakes; completely redesigned nose section and radome (once again showing resemblance with F-22/F-35); dielectric panels in the front fuselage below the completely redesigned canopy; EOTS (Electro-Optical Targeting System); differently shaped gear bays and slightly different tail fins tips.

Use the top image to check on the one below (click for a higher resolution image) some of the differences between J-20 “2001” (first prototype) and J-20 “2011”. Source theaviationist.com

On 13 Sep, 2015 a new prototype, marked ‘2016’, begun testing. This prototype has noticeable improvements, such as apparently changed DSI bumps on the intakes, which save weight, complexity and radar signature. The apparent shape change of the 2016’s DSI suggests the possibility of new engines to power the fighter.

Image @airwar.ru“2016”  showing new DSI @china-defense.blogspot.com

Altering the shape of the DSI suggests that this prototype may have more powerful engines than its predecessors, likely to be an advanced 14 ton thrust derivative of the Russian AL-31 or Chinese WS-10 turbofan engines, though, by 2020 the J-20 is planned to use the 18-19 ton WS-15 engine, enabling the jet to super-cruise without using afterburners. The flight booms around the engines have been enlarged, possibly to accommodate rearwards facing radars or electronic jamming equipment. It also has a stealthier bumper.

Image @defenceforumindia.comImage @china-defense.blogspot.com

The fuselage extends almost all the way to the engine’s exhaust nozzles. The trapezoidal booms on sides of the nozzles are also reshaped, possibly to install rearwards facing radar or ECM equipment. Chinese engineers work overtime to optimize the J-20’s performance for its projected debut. Most interesting are the J-20’s engines. Compared to its “2014” and “2015” predecessors, the J-20’s fuselage contains more of engine’s surface area inside the stealthy fuselage, which would provide greater rear stealth for the J-20 against enemy radar.

“2015” seen with extended refueling probe @military.cnr.cnSeen here testing is “2015” @i19.servimg.com

In late November, 2015; a brand new J-20 prototype numbered 2017 took to the sky. According to the latest source, the design of J-20 is already mature and will not directly use the 117S engine.

“2011” vs “2017”, the “nose comparison” @china-defense.blogspot.com

Production

In late December, 2015, a brand new J-20 numbered 2101 was spotted. The 2101 was believed to be the low rate initial production (LRIP) version of the aircraft.

J-20 enters service with People’s Liberation Army Air Force (PLAAF): Here

China’s ambition for ‘first-class’ navy nears reality with new fighter jet: Here

In a report late on Thursday, state television’s military channel confirmed the J-20 had now entered service, though it gave no other details.

KJ:分享J20精美桌面CG

Design

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Characteristics

Chengdu J-20 prototype

The J-20 has a long and wide fuselage, with the chiseled nose section and a frameless canopy resembling that of the F-22 Raptor. Immediately behind the cockpit are low observable intakes. All-moving canard surfaces with pronounced dihedral are placed behind the intakes, followed by leading edge extensions merging into delta wing with forward-swept trailing edges. The aft section features twin, outward canted all-moving fins, short but deep ventral strakes, and conventional round engine exhausts.

One important design criterion for the J-20 describes high instability. This requires sustained pitch authority at a high angle-of-attack, in which a conventional tail-plane would lose effectiveness due to stalling. On the other hand, a canard can deflect opposite to the angle-of-attack, avoiding stall and thereby maintaining control. Canard is also known to provide good supersonic performance, excellent supersonic and transonic turn performance, and improved short-field landing performance compared to the conventional delta wing design.

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Leading edge extensions and body lift are incorporated to enhance performance in a canard layout. This combination is said by the designer to generate 1.2 times the lift of an ordinary canard delta, and 1.8 times more lift than an equivalent sized pure delta configuration. The designer claims such combination allows the use of a smaller wing, reducing supersonic drag without compromising transonic lift-to-drag characteristics that are crucial to the aircraft’s turn performance.

According to the Jamestown Foundation, the J-20 has the potential for development into a high performance stealth aircraft comparable to the F-22 Raptor, with given appropriate engines.

“2016” J-20 clearly shows side compartments for WVR missiles @c2.staticflickr.com

 

Engines

The prototype’s engine is believed to be initially powered by WS-10 and / or the AL-31F engines. China is currently working on an advanced domestic turbofan engine similar in performance to the Pratt & Whitney F119 coded WS-15, but there are also speculations that Saturn AL-31#117S engine may be used for the initial batch of the J-20.

 AL-31 or Saturn 117s engine@leteckemotory.czWS-15 seen here under testImage @redstar.gr

At the 2012 Zhuhai Air Show, Russia approached China in an unsuccessful bid to sell the Su-35, which included the 117S engines. According to the latest news, China and Russia signed a contract for 24 Su-35 in November, 2015. However, Chinese source stated that the design of J-20 is mature and it will not directly use 117S engine.

See details of Su-35: HERE

su35_0Su-35

Russia to supply first four Su-35 fighters to China in 2016: HERE

Curved nozzle technology for J-20 fighter’s engine will make the fighter a VTOL one in the future

engine-for-vtol-aircraft

The injection of huge fund and Chinese scientists and engineers’ enthusiasm to realize their China dream enable China to achieve fast development of its advanced aircraft engines and soon surpass the United States.

For example, Both Russian and US medias speculate that China has made breakthrough in developing WS-15 engine for its stealth fighter jet J-20 so that the fighter will be able to use China-made engines to be free of its dependence on Russian engines.

It is said that WS-15 is the core of China’s SF-A engine with a thrust 28,700 lb, which if used in J-20 heavy stealth fighter will make it surpass the US in power and maneuverability.

Moreover, as China imported Russian Yak-141 VTOL technology, the WS-15 will have a curved nozzle to enable it to take off and land vertically at a short distance so that J-20 will be China’s next generation of carrier-based fighter jets.

However, China’s ambition does not stop here.

It has developed WS-20 engine with a thrust-to-weight ratio above 9 for its Y-20 large transport aircraft and WS-118 (also known as WS-20 or CJ-2000) engine with a thrust of 26,500 lb that has already been used on its J-10 and J-11B fighter jets. Research and development has begun for a new generation of medium-thrust engine with thrust-to-weight ratio exceeding 9. Preparations are being made for test flight of the aircraft installed with WS-15 fourth-generation engine with a thrust-to-weight ratio of 10.

Test flight of its aircrafts using an improved version of Taihang Engine will be conducted in the coming few years to provide power for China’s new generation of stealth drones, stealth attack drones, long-range drones and manned long-range stealth bombers. At the same time preliminary research has begun in developing an improved fourth-generation military engine with a thrust-to-weight ratio of 12.

As the best US engine F-119-PW-100 used by F-22 stealth fighter jet has only a thrust-to-weight ratio of 8, the above engines Chins is developing fully indicate China’s ambition to surpass the United States.

Engines for civil aircraft are not neglected. An engine with a trust of 30,000 lb is being developed in Shenyang not only for large military transport but also for C-919 large airliner China is developing.
Source: qianzhan.com “Curved nozzle technology for J-20 fighter’s engine will make the fighter a VTOL one in the future” (summary by Chan Kai Yee) Source errymath.blogspot.com

R-79V-300

R-79V-300 is the first-ever engine with thrust vectoring and afterburner at the same time. This allowed the engine equipped plane to take off and land vertically and also to fly supersonically. Engine developement started probably in 1977 under the lead of V. A. Kobchyenko.

r79v-300

The exhaust nozzle which comprises of two rotating sections. Their mutual rotation allows the exhaust flow to be divertes 62 or 95 degrees down with no restriction to power setting of the engine. You can see the function of such nozzle on american F-35 plane. The nozzle is usable only for takeoff and landing, is not intended to improve maneuverability. It’s service life is at least 1500 cycled Její životnost je nejméně 1500 turn cycles. Control system of engine is electronical with hydromechanical backup.

yak_141_2011-1500-x-655

The production version of the J-20 is believed to be the WS-15, a turbofan engine currently under development. According to Global Security, the engine core, composed of high pressure compressors, the combustion chamber, and high pressure turbines were successfully tested in 2005. An image of the core appeared in the 2006 Zhuhai Air Show.

Avionics

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The aircraft features a glass cockpit, with two main large color liquid crystal displays (LCD) situated side-by-side, three smaller auxiliary displays, and a wide-angle holographic head-up display (HUD).

A PLAAF Tupolev Tu-204 testbed aircraft was seen featuring a J-20 nose cone. It is believed to house the Type 1475 (KLJ-5) active electronically scanned array (AESA) radar with 1856 transmit/receive modules.

Chengdu J-20 © Konstantinos PanitsidisShows position of radar housing @redstar.grTu-204 Tests J-20 Radar – Tu-204 number 769, a Russian origin jetliner belonging to the PLAAF’s flight testing regiment, is now testing a radar for the J-20 fighter, as shown in a television clip.

The China Test Flight Establishment’s (CTFE) Tu-204 has been modified to carry a stealth fighter radome on its nose. Previously, the Russian origin Tu-204 jetliner had been reported to test Chinese air to air refueling technologies. Given the shape and large size of the radome, it is likely that the radar being carried by the Tu-204 is for the J-20 fifth generation fighter. The projected radar for the J-20 is likely the Type 1475 Active Electronically Scanned Array (AESA) radar, which provides improved range, transmission power and frequency compared to 1970s era mechanically scanned radars. The F-22’s AN/APG-77 radar was also tested on a Boeing 757 during its development.

Chinese Fighters’ AESA Radars – Shown here are photos and line drawings of Chinese AESA radars. The top one is for the J-10B fighter and has about 1200 transmit/receiver (T/R) modules, the middle one is for the J-16 strike fighter and has 1760 T/R Modules. The bottom one destined for the J-20 5th generation stealth fighter, and has 1856 T/R modules (generally, the more T/R modules on an AESA radar, the more powerful and flexible it is).

The current J-20 prototypes, numbers 2001, 2002 and 2011, most likely carry AESA radars themselves to test the radar performance and to simulate the characteristics of production J-20s as closely as possible. Even so, the People’s Liberation Army Air Force (PLAAF) would want to also test the Type 1475 radar on a jetliner, since the larger aircraft have additional space to provide onsite monitoring and diagnosis by engineers and equipment. Having a dedicated Tu-204 test platform for the J-20’s radar would also allow CTFE to schedule flight tests solely on the needs of evaluating the radar; the test flight schedules of the J-20s would also have to factor in questions about engines, stealth and maneuverability. Source popsci.com

T/R module count of US AESAs based upon the 2001 Defense Science Board report “Future DoD Airborne High-Frequency Radar Needs/Resources”Image Credit: Air Power Australia, 2008.Image @img.ifcdn.com

Prototype “2011” featured a revised nose section with elements resembling a IRST/EOTS system, and a metal finish that loosely reminds the radar absorbing Haze Paint first used on F-16s, and reportedly included sensor fusion technology.

A-Star’s EOTS-86

A-Star’s EOTS-86 appears to be similar to the Electro-Optical Targeting System (EOTS) that equips the Lockheed Martin F-35. Source: Via Top81 web page @janes.com

The EOTS-89 resembles the Electro-Optical Targeting System (EOTS) of the Lockheed Martin F-35, which combines Forward Looking Infrared and Infrared Search and Track (IRST) capabilities. The similarity includes the use of two tracking mirrors and a flat-facetted optical window, with bottom fuselage placement just aft the radar radome. Such a system was so placed on the large mock-up of the FC-31 seen in November 2014.

A-Star’s EORD-31 IRST

A-Star's EORD-31 IRST uses a unique faceted sensor dome. (Via Top81 web page)A-Star’s EORD-31 IRST uses a unique faceted sensor dome. (Via Top81 web page) @janes.com

A-Star’s EORD-31 serves as an IRST, similar to the OLS-27 series used by the Russian Sukhoi Su-27 fighter. However, instead of a spherical dome cover, the EORD-31 is flat and facetted. Chinese press reports claimed the system may be able to detect a Lockheed Martin F-22A at 110 km and a Boeing B-2 at 150 km. Source janes.com

Chinese company A-Star Science and Technology has developed the EOTS-89 electro-optical targeting system and EORD-31 IRST for the J-20 and potentially other PLAAF fighters to detect and intercept stealth aircraft.

Armament

The main weapon bay is capable of housing both short and long-range air-to-air missiles (AAM) (PL-9, PL-12C/D & PL-21).

China PL-10E AAM with anti-stealth capability: Here

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Key Points

  • The PL-10E will be sold as a potential weapons upgrade for existing 4th-generation fighter fleets, or as part of a package with the Chengdu J-10B or Shenyang FC-31 fighter aircraft
  • PL-10/PL-10E has a maximum range of 20 km

During the 11th China International Aviation & Aerospace Exhibition, or Zhuhai Air Show 2016, China unveiled the PL-10E, an export variant of the PL-10 5th-generation short-range imaging infrared (IIR) homing air-to-air missile (AAM), which itself intended to equip the People’s Liberation Army Air Force (PLAAF) 5th-generation stealth fighter aircraft.

The PL-10 SRAAM is produced by the Luoyang-based China Air-to-Air Guided Missile Research Institute (formerly the Luoyang Electro-Optics Technology Development Centre), a subsidiary of the Aviation Industry Corporation of China (AVIC) consortium, and the designer and manufacturer of all infrared (IR) homing variants in China’s PL (Pi Li/Thunderbolt) series AAMs. 

PL-9 air-to-air missile

The PL-9 was introduced during the 1990s, and is a separate evolution of the PL-5 series, with capabilities similar to the AIM-9L/M (image © 2009, Zhenguan Studio). Source ausairpower.net

PL-10 air-to-air missile

PL-10  (K/AKK-10?) is the new generation IIR-guided missile in the same class of AIM-9X, ASRAAM, A-Darter, AAM-5 and IRIS-T. It features an IIR seeker (containing a 128×128 focal plane array?) and TVC, plus a 90° off-boresight angle and 50g max load. When coupled with HMD worn by the pilot, the missile possesses an excellent IRCCM capability against modern fighter aircraft maneuvering at high-gs. It also has a “lock-after-launch” capability, which could extend its range to BVR. Similar to AAM-5 and IRIS-T, the latest design (circa 2013) features 4 enlarged tail stabilizing fins plus 4 narrow stabilizing strips attached to the mid-section of the missile body, which help maintain missile’s maneuverability at the terminal stage after the solid motor stops working. PL-10 has a length of 3m, weight 89kg and range >20km. Source chinese-military-aviation.blogspot.com

PL-12C/D long-range air-to-air missile

A PL-12 active radar homing AAM was being fired from a PLAN J-10A fighter. PL-12 (K/AKK-12?) was under development at LETRI/607 Institute since early 90s. The missile was expected to be in the same class as AIM-120A/B and its active seeker may have evolved from the earlier AMR-1 design (R-129? based on Russian 9B-1348 seeker & datalink for R-77). Its tailfins appear to have fin tips as well as the leading edges of the fin root cropped. These specially designed tailfins are believed to possess lower drag for greater speed and higher torque for better maneuverability. Two datalink antennas can be seen next to the nozzle for mid-course correction. Several dielectric strips are seen along the middle warhead section which house the radio proximity fuse. Source chinese-military-aviation.blogspot.com

PL-21 long-range air-to-air missile

Long-range active radar homing AAM PL-21

A new long-range active radar homing AAM has been under development which appears similar to British Meteor. It features an active radar seeker and an integrated ramjet/solid rocket motor with a single or twin belly air inlets. PL-21 also features 4 small stabilizing fins behind the active radar seeker, a characteristics of Russian R-27/AA-10. Two-way datalink antennas may be installed in the tail section for mid-course correction. The effective range of PL-21 is expected to be >120km. Source chinese-military-aviation.blogspot.com

Two smaller lateral weapon bays behind the air inlets are intended for short-range AAMs (PL-9). These bays allow closure of the bay doors prior to firing the missile, thus enhancing stealth.

1_jpgf4b38d8b-92bd-4956-bbf3-eaa10eca236bOriginalTwo smaller lateral weapon bays behind the air inlets are intended for short-range AAMs (PL-9) depicted above 3D model

Stealth

Analysts noted that J-20’s nose and canopy use similar stealth shaping design as the F-22, yielding similar signature performance in a mature design at the front, while the aircraft’s side and axi-symmetric engine nozzles may expose the aircraft to radar. One prototype has been powered by WS-10G engines equipped with a different jagged-edge nozzles and tiles for greater stealth.

Nutg494Example exhaust nozzle

The Chengdu J-20: Peace in Our Time?

Excerpt

Let’s put these august pontifications through the prism of the software simulator running the ‘Physical Optics’ specular reflection model of the J-20. Readers are encouraged to access and digest this analysis, but for the busy, here is the abstract verbatim:

This study has explored the specular Radar Cross Section of the Chengdu J-20 prototype aircraft shaping design.

Simulations using a Physical Optics simulation algorithm were performed for frequencies of 150 MHz, 600 MHz, 1.2 GHz, 3.0 GHz, 6.0 GHz, 8.0 GHz, 12.0 GHz, 16.0 GHz and 28 GHz without an absorbent coating, and for frequencies of 1.2 GHz, 3.0 GHz, 6.0 GHz, 8.0 GHz, 12.0 GHz, 16.0 GHz with an absorbent coating, covering all angular aspects of the airframe.

In addition, the performance of a range of Chinese developed radar absorbers was modelled, based on a reasonable survey of unclassified Chinese research publications in the area.

None of the surveyed materials were found to be suitable for use as impedance matched specular radar absorbers.

Modelling has determined, that if the production J-20 retains the axisymmetric nozzles and smoothly area ruled sides, the aircraft could at best deliver robust Very Low Observable performance in the nose aspect angular sector.

Conversely, if the production J-20 introduces a rectangular faceted nozzle design, and refinements to fuselage side shaping, the design would present very good potential for  robust Very Low Observable performance in the S-band and above, for the nose and tail aspect angular sectors, with good performance in the beam aspect angular sector.

This study has therefore established through Physical Optics simulation across nine radio-frequency bands, that no fundamental obstacles exist in the shaping design of the J-20 prototype precluding its development into a genuine Very Low Observable design.

Chengdu-J-20-[2mm-Ferrite---4mm-CFC].mdb-01.20GHz-RsFromCoating-IncPol-TM-Pol-Theta-[E=135.0-A=315.0].pngAbove: L-band RCS, below X-band RCS head on, both in PCSR format (M.J. Pelosi).chengdu-j-20-2mm-ferrite-4mm-cfc-mdb-08-00ghz-rsfromcoating-incpol-tm-pol-theta-e090-0-a180-0

Engineers and Scientists who work in ‘stealth’ (AKA ‘Low Observable’) designs have a way for explaining it to lay people: ‘Stealth’ is achieved by Shaping, Shaping, Shaping and Materials (Denys Overholser).

The F-22A is clearly well shaped for low observability above about 500 MHz, and from all important aspects. The J-20 has observed the ‘Shaping, Shaping, Shaping’ imperative, except for the axisymmetric nozzles, and some curvature of the sides that smears a strong, but very narrow specular return into something of a more observable fan. The X-35 mostly observed the ‘Shaping, Shaping, Shaping’ rule, but since then, to quote a colleague, ‘hideous lumps, bumps, humps and warts’ have appeared on the JSF to disrupt the shaping imperative, forcing excessive reliance on materials, which are at the rear-end of the path to ‘Low Observability’.

While discussing ‘rear-ends’, both the F-35 and the J-20 have large signature contributions from their jet nozzles. However, the difference is much like the proverbial ‘Ham Omelette’: the F-35 Pig is committed, but the J-20 Chicken is a participant. If the Chinese decide that rear sector Low Observability is tactically and strategically important, they are at the design stage where they can copy the F-22A nozzle design for the production configuration of the J-20.

In a market now dominated by “a total indifference to what is real”, no such option is now or ever was possible for the JSF, as its design is based upon meeting the bare minimum (a.k.a. “Threshold”) requirements of the JORD wherein “excellence is the enemy of good enough”; as has the STOVL F-35B as the baseline design; and, thus, is heavily constrained by the specified roles for this aircraft as well as the risks to reputations based political imperatives of accelerating a much-delayed and grossly over-budget program.

The issue of the use of materials to suppress radar signature is interesting. Publications show that the Chinese are making a substantial investment in use of materials to reduce radar signature and have produced large volumes of research results. So far, there have been no Chinese public disclosures on materials that make a substantial reduction of signatures across a broad range of air combat radar frequencies. Come to think of it, there are no United States research papers on the subject. Why is that, one wonders?

Let’s revisit the opinions expressed about the J-20 soon after its maiden flight.

Source ausairpower.net

Others have raised doubts about the use of canards on a low-observable design, stating that canards would guarantee radar detection and a compromise of stealth.

However, canards and low-observability are not mutually exclusive designs. Northrop Grumman’s proposal for the U.S Navy’s Advanced Tactical Fighter (ATF) incorporated canards on a stealthy airframe. Lockheed Martin employed canards on a stealth airframe for the Joint Advanced Strike Technology (JAST) program during early development before dropping them due to complications with aircraft carrier recovery. McDonnell Douglas and NASA’s X-36 featured canards and was considered to be extremely stealthy. Radar cross-section can be further reduced by controlling canard deflection through flight control software, as is done on the Eurofighter.

Comparison to the Mig-1.44 @4.bp.blogspot.com

Some have claimed it as a reworked Mig-1.44 : snafu

The diverterless supersonic inlet (DSI) enables an aircraft to reach Mach 2.0 with a simpler intake than traditionally required, and improves stealth performance by eliminating radar reflections between the diverter and the aircraft’s skin. Analysts have noted that the J-20 DSI reduces the need for application of radar absorbent materials. Additionally, the “bump” surface reduces the engine’s exposure to radar, significantly reducing a strong source of radar reflection.

Strategic implications

Military

Robert Gates downplayed the significance of the aircraft by questioning how stealthy the J-20 may be, but stated the J-20 would “put some of our capabilities at risk, and we have to pay attention to them, we have to respond appropriately with our own programs.” The U.S. Director of National Intelligence James R. Clapper testified that the United States knew about the program for a long time and that the test flight was not a surprise.

Loren B. Thompson felt that J-20’s combination of forward stealth and long range puts America’s surface assets at risk, and that a long-range maritime strike capability may cause the United States more concern than a short range air-superiority fighter like the F-22. In its 2011 Annual Report to Congress, the Pentagon described the J-20 as “a platform capable of long range, penetrating strikes into complex air defense environments.” A 2012 report by the U.S.‐China Economic and Security Review Commission suggests that the United States may have underestimated the speed of development of the J-20 and several other Chinese military development projects.

Observers are not able to reach a consensus on J-20’s primary role. Based on initial photographs with focus on the aircraft’s size, early speculations referred to as the J-20 as a F-111 equivalent with little to no air-to-air ability. Others saw the J-20 as a potential air superiority fighter once appropriate engines become available. More recent speculations refer to the J-20 as an air-to-air fighter with an emphasis on forward stealth, high-speed aerodynamics, range, and adequate agility. The J-20 could threaten vulnerable tankers and ISR/C2 platforms, depriving Washington of radar coverage and strike range.

Luneburg lens radar reflector

ctmwtxavyaaaorjAnother one by eaglephoto,note the luneburg lens radar reflector on the belly – Image @dafeng caof-22_luneberg_500-375Example pic of luneburg lens radar reflector

The Luneberg reflector gives an homogeneous response inside a wide angle. It is an ideal passive responder, perfect for highlighting, and eventually monitoring the radar target to which it is attached, with a high level of security.

The Luneberg lens is the most efficient passive radar reflector available.
The Luneberg reflector requires no power supply nor maintenance.

Source radar-reflector.com

Cyber security

In April 2009, a Wall Street Journal report indicated that, according to the Pentagon, information from the Lockheed Martin F-35 Lightning II had been compromised by unknown attackers that appeared to originate from China. There is some speculation that the compromise of the F-35 program may have helped in the development of the J-20.

Specifications

Data from Aviation Week & Space Technology

General characteristics

  • Crew: one (pilot)
  • Length: 20 m (66.8 ft)
  • Wingspan: 13 m (44.2 ft)
  • Height: 4.45 m (14 ft 7 in)
  • Wing area: 78 m2 (840 sq ft)
  • Empty weight: 19,391 kg (42,750 lb)
  • Gross weight: 32,092 kg (70,750 lb)
  • Max takeoff weight: 36,288 kg (80,001 lb) upper estimate
  • Fuel capacity: 11,340 kg (25,000 lb)
  • Powerplant: 2 × WS-10G (prototype), AL-31F (prototype) or Xian WS-15 (production) afterburning turbofans, 76.18 kN (17,125 lbf) thrust each dry, 122.3 or 179.9 kN (27,500 or 40,450 lbf) with afterburner
  • Wing loading: 410 kg/m2 (84 lb/sq ft)
  • Thrust/weight: 0.94 (prototype with interim engines)

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Armament

  • PL-10 SRAAM (see above)
  • PL-12 Medium Range AAM (see above)
Image @globalsecurity.org

J-20 production makes maiden flight

Successful landing of the maiden flight of the first series-produced J-20 stealth fighter jet “2101” @tiananmenstremendousachievements.wordpress.com

In its report yesterday on the series production of China’s J-20 stealth fighter jet, mil.huanqiu.com says that according to experts, it takes less than five years for China from the maiden flight of the first experimental prototype to series production, the shortest ever in the world. That is indeed impressive, but there have not been enough test flights. They believe there will be more test flights of even the existing prototypes.

This blogger said in his previous posts that China began the series production of J-20 due to its urgent need for air supremacy in case of a military conflict with the US.

This is also proved by its import of Russian S-400 air defense system and Su-35 fighter jets, especially the high price of US$1.5 billion it pays for 24 Su-35s. In fact, its improved version of J-11, the J-11C, comes near to Su-35 in functions. Why is China willing to pay such a high price? Because, it can learn some technology it urgently needs from Su-35 especially its engine.

Global Times quotes an anonymous Chinese military expert as saying that like F-35, there is a large software in J-20 that needs much test; therefore, there must be further improvement during the trial use when the series-produced J-20s have been put into trial service in Chinese air force.

The expert believes that there is still a long way to go for China’s J-20 as the engines it uses cannot meet its designed standards. Only when a J-20 is installed with engines with a thrust-weight ratio of 10 can J-20 be regarded as a perfect fourth-generation fighter jet.

Source: mil.huanqiu.com “Has trial series production of J-20 begun?: Perhaps like F-35, it will be improved while being used” (summary and comments by Chan Kai Yee based on the report in Chinese) Source tiananmenstremendousachievements.wordpress.com Posted 

117S engine waits at Komsomolsk-on-Amur Aircraft Production Association (KnAAPO) plant for a Su35

Russian media reported that both China and Russia are interested in subsequent cooperation on fighter engine field. During his visit in Russia, Xu Qiliang visited Russia’s largest engine manufacturer and watched production of AL-31 engine, the factory’s leader said they will implement the agreement on exporting 117S engines for Su-35 to China.

Chinese military analysts think China may import technology of TVC engine AL-41F1S (117S), and may also buy this engine for J-20 stealth fighter.

Analysts said China still cannot produce TVC engine (thrust vectoring control engine) for J-20 fighter, but might had been started related R&D. And 117S engine may promote such research work. Source china-arms.com Posted  November 23, 2015

J-20 Uses Homegrown WS-15, More Powerful, Reliable than Russian AL-31F

The above photo of series produced J-20 proves that it uses China’s WS-15 engines as there are no grooves on the nozzles of its engines.

The photo below is the nozzle of Russian AL-31F engine used on J-20 prototypes. There are two groves on the nozzle.

The photo below is the nozzle of China’s homegrown WS-15 engine with no grooves on it.

According to the photo below, WS-15 is much more powerful than AL-31F. The AL-31F’s nozzle has shrunk so that the speed of smoke is much higher than that of the WS-15 with nozzle not shrunk while they produce similar thrust for the J-20.

The article reveals that the temperature before turbine is 1,474 degree Celsius in WS-15, the highest in the world. No wonder WS-15 is much more powerful than AL-31F. Its reliability lies between Western and Russian ones with a life of 900 hours longer than AL-31F.

Since the engine problem has been solved, J-20 can be regarded as a capable modern stealth fighter as it has satisfactory electronics and stealth shape.

Source: mil.news.sina.com.cn “Depth Column: It is certain that homegrown WS-15 engines are installed on J-20: Reliability surpasses Russian engine?” (summary by Chan Kai Yee based on the report in Chinese) Source linkedin.com

size comparison the J-20 is as big as an Su-27 @img.gawkerassets.comJ-20 for aircraft carrier rendered @snafu-solomon.blogspot.com

Specification from Chinese source

Crew: 1

Length: 21.26 Meters (69.75 Feet)
Wing span: 12.88 Meters (42.26 Feet)
Canard span: 7.62 Meters (25.00 Feet)
Height 4.45 Meters (14.60 Feet)

Empty weight 17 Tons
Loaded Weight?: 25 Tons

Maximum speed: (When Powered with WS-15 turbofan engine)
At altitude: Mach 2.5 (1903 mph, 3062 km/h)
Supercruise Speed : Mach 1.83 (1393 mph, 2442 km/h)

Service Ceiling: 20000 Meters (65620 Feet)

Combat Radius: 2000 Kilometers (1243 Miles)
Ferry Range: 5500 Kilometers (3418 Miles)
(The authenticity of the Image with specifications of the J-20 Mighty Dragon Stealth Fighter Jet is questionable) Source chinesemilitaryreview.blogspot.com

Main material source: wikimedia.org

Updated Mar 11, 2017

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