China Develops Stealth Fighter Military Technology

China is developing new 5th generation "stealth" fighter, which isbeing developed under a programmed variously referred to as XXJ, J-X,or J-XX by Western intelligence sources and is apparently designated asJ-14. Here, Coniglio details China's internal installations and fullscale development of J-14.

 
The first picture has recently become available of the new Chinese 5thgeneration "stealth" fighter. The aircraft, which is being developedunder a programme variously referred to as as XXJ, J-X or J-XX byWestern intelligence sources (the real Chinese name is not known), isapparently designated as J-14.

The aircraft in the above photo looks at first sight as a completeprototype, but it  
actually is a very detailed full-scale engineeringmock-up. It can be speculated that, after having been used to study theaircraft's internal installations, the mock-up has also received anexternal finish for presentation purposes. Its real function at thispoint, however, is probably to buttist in the definition of therequired logistic support (i.e., access to the various avionics boxesand on-board systems, ground support equipment like the various laddersand the external power source units, air conditioning units and so on)as well as to study the engines' removal-installation procedures.
 

Since some time now it has been known that the rapidly-developingChinese aeronautical industry is studying a new and technologicallyvery advanced combat aircraft, also boasting significant low signaturecharacteristics. This programme is a logical step in China's "LongMarch" towards full independence in designing, developing and producingcombat airplanes of a technological level in line with China's statusas the "other" world superpower, on an equal footing as Russia andeventually even the USA.

The scarce information available about this new advanced combataircraft indicates that two, possibly competing, study groups (bothpart of the AVIC I Group of aeronautical industries) are or have beenworking on the subject. One of these groups (601 Insbreastute)originates from Shenyang Airplane Corporation (SAC) which is in chargeof the large, twin-engine J-8 fighters in service with the PLAAF(People's Liberation Army Air Force) as well as of licence productionof the Su-27SK under the local designation of J-11. The overallconfiguration of SAC's preliminary design, apparently designated J-13,owes significantly to the American F-A-22, being a tailed delta butwith wing and horizontal tailplanes more in line with those of theF-16. The other study group (611 Insbreastute) from Chengdu AirplaneCorporation (CAC), has developed the J-12, a concept which follows theless conventional canard layout used with success in the company's J-10.

While previous information (albeit admittedly unconfirmed), gave to theSAC concept the edge, perhaps as a result of the company's experiencein large twin-engine fighters, this seems to have since been reversedin favour of the Chengdu design. It is however still not clear whetherthe designation of J-14 is intended to suggest a successor design toboth the J-12 and the J-13, and whether the existence of the J-14engineering mock-up (clearly based on the J-12) indicates that the typehas been selected for development, or the compebreastion is still goingon with parallel activities underway on another such mock-up based onthe J-13.

While no data is available about the J-14, some speculation can be donein the attempt to extrapolate the aircraft's characteristics and thusthe roles it is called to perform. The following considerations arebased on what can be seen in the photo, but also involve making somebuttumptions on the basis of what is known of the Chinese armed forces'perceived priorities in operational requirements, the domesticindustry's approach to combat aircraft design and, finally, thewell-know Chinese weaknesses in some technological fields. In addition,the well-developed cooperation with Russian companies, particularly inareas such as powerplant, avionics and possibly computer-basedfly-by-wire flight control systems is also taken into consideration.
General Configuration

The J-14 will surely be fitted with a fly-by-wire flight control systemand be designed for artificial stability. The Chinese should by nowhave matured an adequate experience in this field through a number ofexperimental programmes and application to actual in-service types.

The general configuration of the aircraft is clearly born out fromCAC's experience in developing the J-10, with its canard layout andventral air intake. But while the J-10 is known to be related to theIsraeli LAVI, this new and much more ambitious design rather appears tohave a definite relationship with the ill-fated Russian 5th generationfighter studied a few years ago, the MiG 1.44 MFI and in fact it sharesa number of elements which can doubtless be traced back to the Russiandemonstrator. It is thus very probable not to say certain that anagreement has been reached between the Russian and Chinese governmentsallowing for the transfer of information and technological data as wellas consultancy services being provided by RSK MiG and Russian researchcentres (arguably including the TsAGI aerodynamic researchinsbreastute) to develop the new Chinese fighter.

The J-14's planform closely matches that of the MiG 1.44, i.e. a canardlayout (the canard surface are fully movable) with mid-positioned wingand widely separated twin-vertical surfaces canted outward, whichcontinue under the wing in twin ventral fins, these too being cantedoutward à la J-10. While not visible in the photo, wind tunnel modelsshow that the 1.44 configuration has been maintained also in the boomsprotruding from the wing and contributing to support the verticaltailplanes and ventral fins. These booms probably end with radomescovering electronic warfare antennas and possibly also a rearwardfacing radar, similar to the installation experimented in the Su-37 afew years ago. In the MiG 1.44, the portion of wing between thefuselage-engine pods and the booms is extended rearward past the wingtrailing edge and includes a couple of moving surfaces contributing,together with the all-moving canard surfaces, to the longitudinalcontrol of the airplane. It is not yet possible to buttess whether thissolution, too has been maintained for the J-14.

But while the overall aerodynamic configuration of the J-14 followsthat of the MiG 1.44 demonstrator, a radical redesign has beenimplemented in the pursuit of a significant reduction in the radarcross-section value. In particular, the aircraft incorporates apronounced wing-body blending, which was totally lacking in theoriginal Russian design. Further, the air intake, while in the sameventral position under the forward fuselage, has a completely newshape, and by the same token the upper part of the airplane is alsocompletely different and shows towards the rear the protuberances ofthe engine "pods" which blend with the fuselage and wing roots in acurious reminiscence of the Northrop YF-23. Also, the front fuselagemerges down into the upper wing, blending with the separated engine baybulges while maintaining some relation with the "clbuttical" Su-27forward fuselage shape. The search for enhanced stealth performance isalso apparent in the "flattened" profile of the entire front fuselagesection (nearly identical to the Su-32), as well as in the generaliseduse of serrated doors to cover the landing gear and missile bays.

On the other hand, it remains clear that a canard configuration ishardly the ideal solution from the point of view of a reduced radarsignature. Summing up, it would thus seem safe to buttume that the J-14is a "stealth-optimised" aircraft rather than un uncompromising stealthdesign à la F-A-22 or (in a different clbutt) the F-35 JSF.

Above the raised front fuselage is located the single-seat pilotchickenpit. This is closed by a single-piece frameless bubble-typetransparent canopy which appears technological very demanding undervarious aspects such as manufacturing process, adequate opticalqualities and bird-impact resistance, yet allowing through-ejection. Onthe other hand, the pilot is provided with superb all-around visibilityalso due to the position of the chickenpit above the forward fuselage"hump", again a reminiscence of the Su-27.
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The main landing gear, with single wheels mounted on telescopic legs,retracts outward, with the legs being accommodated in the fuselage sideblending into the wing bottom and the wheels into the wing (a similargeometry has been selected for the F-A-22). In order to minimise thevolume of the bay occupied by the gear in the retracted position, thetelescopic main gear legs are shortened via a pulling bar acting on alever, similarly to what has been introduced in the EurofighterTYPHOON. While not clear in the photo, it is possible that the samelanding gear leg shortening design has also been selected for the nosetwin-wheel element.
Powerplant Installation

In view of the twin-engine layout of the J-14 and its estimated TOweight in air combat configuration (some 25-28 tons with full internalfuel, gun ammunition, 2 x SRAAM and 4 x MRAAM), its engines should givea thrust in the range of 13-14 tons in afterburning mode, so achievinga thrust-to-weight ratio in the order of 1:1. Now it seems difficult toenvisage a stateof-the-art Chinese engine, particularly in this thrustclbutt, achieving full production status by the mid of the next decadewhen the J-14 could reasonably be expected to enter service. Even forthe J-10 a Russian engine has been at last preferred. It can thus bebuttumed that a Russian engine has been selected for the J-14 as well,and indeed the model which can be seen in the picture to the rear ofthe right wing of the mock-up has the accessory gearbox mounted abovethe engine in the traditional Russian style. If, as it is highlyprobable, this engine is a member of the Saturn-Lyulka AL-31-41 family(but it could also be a prototype of the Chinese Liming LM WS10A in thesame thrust clbutt), this would make the type not fully interchangeablewith the version selected for the J-10, which has the accessory gearboxlocated on the engine bottom, Western-style. It is also possible tospeculate that the idea is to have the prototypes powered by thelower-thrust AL-31 as used in the J-11-Su-27SK-Su-30MKK, with either anevolved higher-thrust version of AL-31 or a series-production versionof the AL-41 being then adopted for the series aircraft.

Coming to the engine-airframe installation, the air intake located inthe bottom part of the front fuselage is of the fixed geometry typewith no moving ramp, unlike the case with the J-10. This solution hasmade it possible to eliminate the sharp angles and slots between themoving ramp and in general to provide smooth shapes which reduce radarreflectivity. The pronounced bulging up of the air intake inner ducthelps avoid a direct presentation of the critically reflective enginefan-compressor face to enemy illuminating radar from the forwardemisphere. In addition, the bulge is needed to make room for the noselanding gear bay and, even more, for the bottom fuselage weapons bay.Notwithstanding its fixed geometry, the air intake shows elements whichshould generate a couple of oblique shock waves before the normal one,thus guaranteeing an adequately efficient dynamic pressure recovery inthe supersonic flight regime. The well-shaped bulge along the bottom ofthe centre fuselage entering the air intake, which forms the upper partof the air intake duct, seems reminiscent of the latest LockheedMartin's vaunted design for a fixed-ramp, multi-shock air intakeplanned for use on the production F-35 and already experimented on anF-16. This peculiar layout, together with the forward-raked air intakelip (already seen in the late 1950s on the F8U-3 CRUSADER III) isclearly intended to generate the oblique shock waves mentioned above.

The location of the air intake under the fuselage is well suited toprovide a smooth distortion-free airflow to the engines. From thisparticular point of view, the hinged bottom lip present in the TYPHOONworks even better at extreme angles of attack, but it implies thepenalty of a higher radar signature. In more general terms, the choiceof a single air intake configuration in a twin-engine airplane may beopen to some criticism, in that it is less than ideal to maintaincorrect working conditions (i.e., smooth undistorted airflow to theremaining engine) in the event of an engine flaming out for whateverreason. The air intake thus establishes a potential single pointfailure in an otherwise completely redundant twin-engine installation.

It can be expected that Thrust Vector Control (TVC) nozzles, probablyof the axisymmetric type (despite their not insignificant contributionto overall nuclear signature), will be a standard feature of the J-14to both enhance manoeuvrability and reduce trim drag in cruise flight.
Armament

Chinese design derived from a Russian model such as the GSh-6-23 23mminstalled in the MiG-31 and the Su-24. The gun is installed in theupper right fuselage side, just above the canard surface. The firingport, unlike the F-A-22 is left permanently open, hence generating anot so negligible radar reflection.

The main armament is carried in three weapons bays, whose arrangementlooks like virtually a clone of the F-A-22. Two smaller bays arelocated on the fuselage sides and appear to be tailored to eachaccommodate a single short-range air-to-air missile, while the largeunderfuselage bay, closed by twin doors, will probably accept at leastfour medium-range AAMs. It may be speculated that the J-14 is intendedto carry "compressed carriage" clipped-wing versions of the AAMsalready in use with the PLAAF, i.e. the PL-8 and the Russian R-73 forshort-range dogfights and the R-77 and the indigenous PL-12 formedium-range work. The R-77 is already suitable for carriage in aninternal bay in its standard version, being equipped with very smallspan wings while the lattice tail control fins can be fold forwardflush with the missile body.

Underwing store stations are surely foreseen to carry additionalweapons and fuel tanks, when there is no need to maintain a high levelof stealthness.
Combat Avionics

 J-14 is already in full-scale development, the mainchoices related to the avionics systems should have already been made,at least at the conceptual level. However, the Chinese domesticindustry is almost certainly not in a position to supply the advancedavionics required in a sophisticated aircraft like the J-14, andcontributions from abroad will be required - from Russia, Israel andarguably even Europe.

The J-14 being intended to enter service in around 2012-2015, it may beexpected that the Chinese are aiming at equipping it with a radar withelectronically scanning (ASEA) antenna, capable of multiple targetsengagements - provided that a source for such a radar could beidentified. In the Russian tradition, a pbuttive search and tracksystem based on optronic devices (FLIR with integrated laserrangefinder) is expected to be also installed in a retractable orfaired turret. As already mentioned, the dual rear booms could carry,in addition to various pbuttive and-or active defensive systems also arear-facing radar.

Finally, it can be expected that the chickenpit instrumentation for theproduction version will be based on an Helmet Mounted Display-Sight(HMD-S) totally replacing the HUD, although the latter instrument isclearly visible in the photo. The head-down displays would probablyinclude three or four large Multi Function Displays (MFD), which shouldhave the possibility to present a digital map and a complete tacticalsituation. A real-time data link is also an expected addition to thefully integrated avionics system to enhance the situation awareness ofthe pilot, particularly when operating in multiships combat groups tomake the most use of the commonly available information from thevarious platforms.
Operational Aspects

The most likely enemies that China can expect to have to confront inthe future are India and the USA, this latter possibly as a result of aChinese attempt to follow a military option against Taiwan. Both ofthese potential enemies have powerful air forces equipped with largefleets of state-of-the-art fighters and fighter-planters trained tooperate, in particular the Americans, as complex expeditionary forces,well balanced in their different components and supported by a networkof other essential buttets like satellites, AWACS airplanes, dedicatedelectronic warfare types, aerial tankers, and more in general a wholearray of "force multiplier" elements. Given the expected operationalenvironment, the air defence-air superiority role is obviously thePLAAF's #1 priority, with surface attacks against powerful naval forceswith strong aerial support (i.e., the US Navy carrier task forces)coming possibly as priority #2.

Hence, it is not surprising that the most advanced Chinese combatairplane ever seen appears being tailored to the air combat role,although air-to-surface roles cannot be discarded for futureincorporation into the design. Considering what is known of therelatively modest development pace of Chinese surface attack guidedweapons, currently there seems to be a very limited potential for theinternal carriage of such weapons, and accordingly surface attack rolescould only be carried out by compromising the aircraft's stealthperformance.
Conclusions

Should future information confirm that the aircraft depicted in thisphoto is actually in full scale development, then the J-14 wouldeventually emerge as the first true credible compebreastor to theF-A-22 and its "air dominance fighter" concept. The appearance of sucha similar-clbutt compebreastor in China, and possibly in an unexpectedshort time, will probably be more than enough to justify continuingproduction of the F-A-22 well above the currently planned meagre totalof 179 aircraft.

The Chinese are still lagging behind in a number of criticaltechnologies, but their pace is well set to achieve their aims. Thosewho like to dismiss the Chinese defence industry as being able only toproduce low-quality clones of outdated Western or Russian designs arewell served. Perhaps someone in the USA should possibly remember thegeneral complacent atbreastude towards the "Japs" before 7 December1941, and the very brutal awakening when the ZEROs wiped the P-40s,BUFFALOs and WILDCATS clear off the skies.

Very much the same applies to those European governments that arecurrently playing with the idea of resuming arms sales to China. It isclearly preposterous to fantasise about the possibility of selling theChinese the TYPHOON or the RAFALE to replace their older aircraft; theJ-14 is admittedly still a decade or so away from operational service,but it is clearly intended to be at least half a generation moreadvanced than the European designs. At the very maximum, what can berationally expected are some contracts for the supply of specificequipment which the local industry is not yet capable to produce, andwhich the Chinese can not or would not get from Russia. Whether itwould be in the long-term European interest to supply this equipment,is a different question altogether.
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