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Chinese J-20 and J-31 5th Generation Fighter Jets

Discussion in 'China & Asia Pacific' started by Martian, Dec 23, 2010.

  1. Vritra

    Vritra Major ELITE MEMBER

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    Not sure that this is actually a naval platform. The Chinese already have the Su-27K/Su-33 rip-off, the J-15, under development, which is exclusively for carrier use.

    This fighter on the other hand, its a MiG-29 sized bird. This could be the rumoured "stealth fighter" that China is developing for/with Pakistan, or possibly as a replacement for their own large fleet of 3rd gen aircraft. Maybe both. Low internal fuel volume equals limited range, and small size of aircraft limits internal carriage. Engines, as MiG-23MLD pointed out, likely an RD-33 derivative, possible the WS-15 or RD-93 on the prototype. Nozzle doesn't seem to be TVC type. This is basically the Chinese F-35. Except its twin-engined (with both pointing out the butt, anyway) and not all that ugly. A fighter after the F-16s heart.
     
  2. Vritra

    Vritra Major ELITE MEMBER

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    People are alarmingly quick with digital reconstructions, these days...

    [​IMG]
     
  3. gambit

    gambit FULL MEMBER

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    An 'ogive'...Or 'oh-give-eee'...

    [​IMG]

    In the graph, the ogive (and others) produces a strobe like signature, but this is on the presumption of the existence of creeping wave behavior, aka the 'ten lambda rule', which I explained elsewhere. The B-2, F-22, and F-35 when view from the side aspects have that ogival shape and it is no accident that they look that way. So in order to force these aircrafts to produce that strobe like returns, the seeking radar must operate in meters length freqs, as in tens of meters, and if it does, it will give itself away via so much energy that the 'stealth' adversaries will be able to take evasive/avoidance maneuvers/tactics long before they give themselves away.

    Contrary to popular opinions, the long wavelengths bands does not offer THE definitive solution to counter 'stealth'. We knew this a long time ago but really said nothing about it. No need to. Any radar engineer, even in the commercial sector, can finger that out for himself. That is why only technically ignorant media writers and equally technically ignorant nationalistic bloggers of non-US origins really made a big deal of that 'long wavelength' nonsense.

    The long wavelengths will detect a US 'stealth' aircraft better than the shorter freqs, but only if that 'stealth' aircraft allows it. :lol:
     
    2 people like this.
  4. Picard

    Picard Lt. Colonel RESEARCHER

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    Which can be said for any wavelenght and any aircraft...
     
  5. MiG-23MLD

    MiG-23MLD Major SENIOR MEMBER

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    watch this video at minute 33

    Petr Ufimtsev the Creator & Father of Stealth Technology who developed the math of EM wave radar deflection theory for stealth faceting, claims bistatic radars can be used to detect stealth aircraft. (watch minute 12 and later 33)


    If stealth is detected then you need speed to survive, any fighter if detected will be in danger, specially since the new radar by cassidian is passive, the stealth aircraft does not know when it is detected.

    If fired upon speed will be the last resort to survive.

    On PAKFA the are planning to use the AESA radar sets on the wings to fry the active radars of missiles.

    but speed will give F-22 an advantage if detected, it was proven by MiG-25 that speed allowed it to dodge attacks.


    117, 117S are in production see117Ñ > Ãàó÷íî-ïðîèçâîäñòâåííîå îáúåäèíåíèå ÑÀÒÓÃÃ

    So for China if their engines are not going to be ready in 10 years time buy interim 117s is not a bad idea but Russia is only willing to sell it if they include the jets

    but see
    Application 117S engine has been created by NPO Saturn (Luylka Design Bureau) for Su-35 multirole fighter developed by Sukhoi Company. Geometry and mounts of the 117S engine are similar to its predecessors, i.e. AL-31F and AL-31FP engines. This gives an opportunity to use the 117S engine, with slightly retrofitted engine nacelle and equipment, for the re-engining of earlier built Sukhoi-27/30 fighters, operational by Russian and foreign Air Forces



    Russia is willing to export it and even J-11s can be retrofited see Saturns says that but who knows if the chinese supercruising engine is ready they won`t need it but who knows only time will tell

    But seems China is not ahead in supercruising due to WS-10, Al-31s and RD-33, by the way India builds RD-33

    24.01.2007 // India has acquired the right to manufacture Saint-Petersburg’s engines
    Today Russian Minister of Defence, Vice-Prime Minister Ivanov, has signed a contract on license production of RD-33 series 3 engines in India. Klimov JSC, being the designer of the engine, has been defined as the head enterprise on supply of the design documents.

    The contract in amount of 250 million US dollars provides for the establishment of the production line for 120 upgraded RD-33 engines with increased service life at the base of HAL (Hindustan Aeronautics Limited) Indian Corporation. In addition to the design documents supply Klimov JSC will provide Indian partners with the maintenance and consulting support. In future the technical specialists of Klimov JSC based in Saint-Petersburg will supervise the observance of the RD-93 production technology. Klimov JSC as the designer of the wide range of gas turbine engines takes part in all projects on establishment of the production and repair lines of its products.

    Klimov :: Media Room :: Company News :: India has acquired the right to manufacture Saint-Petersburg
     
    Last edited by a moderator: Mar 12, 2014
  6. gambit

    gambit FULL MEMBER

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    He was not.

    True. He wrote the math. I have his text book on my shelf. But it is nothing remotely any sort of a 'cookbook' to design a radar low observable body.

    True. We never deny it. But a bi-static system is resource intensive in terms of ownership and deployments, to say nothing yet of the technical hurdles that must be defeated when all elements must communicate with each other within one millisec or better in order to have effective detection and tracking of a low observable aircraft.

    Like this...???

    Passive radar from CASSIDIAN remains invisible - Cassidian.com
    First...No such beast as a 'passive radar'.

    Radar detection is a two-parts process: Transmission and Reception.

    The misnomer 'passive radar' came to be when the 'Transmission' part is not under the direct control of the radar owner/operator, as highlighted in the source above. Those transmissions are called 'opportunistic' transmitters, meaning the passive receiver must rely on any transmission sources and uses them opportunistically while they last.

    [​IMG]

    If an adversary degrade or even destroy the main power sources for these opportunistic transmitter, the 'passive radar' is worthless.

    The AMRAAM have a 'beamrider' mode, meaning its radar will not be active. The modes can be switched on/off in missile's flight/pursuit, depending on the tactical situation.
     
  7. MiG-23MLD

    MiG-23MLD Major SENIOR MEMBER

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    tell that to Russian companies that were in MAKS 2011






    only time will tell but already there are companies saying they can detect and down stealth aircraft

    plus F-35 has its detractors

     
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  8. gambit

    gambit FULL MEMBER

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    Amateurishly made. Not a single explanation of 'how' things work.

    Unproven claims. In order to prove for themselves, they should have a 'stealth' aircraft to start.

    All aircrafts does, including the highly successful F-16.
     
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  9. smestarz

    smestarz Lt. Colonel REGISTERED

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    It would be interesting if the Americans did something like Apple and put a case on China for copying its plane. and see how China reacts hahahahah
     
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  10. mcddk

    mcddk FULL MEMBER

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    dude, are u still pretending knowing nothing about Shenyang J-31?
     
  11. MiG-23MLD

    MiG-23MLD Major SENIOR MEMBER

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    [​IMG][​IMG]
     
  12. Gessler

    Gessler BANNED BANNED

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    Don't worry, FireFox is better than any of those Js out there.

    IMHO, the latest of Chinese stealth jets are atleast 20 yrs behind the F-35A in stuff.
     
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  13. MiG-23MLD

    MiG-23MLD Major SENIOR MEMBER

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    [​IMG]
     
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  14. G777

    G777 Lt. Colonel ELITE MEMBER

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    You are suppose to keep things secret :YUNO:

    Dont underestimate others. And those vids is what I expect of Russian weapons.
     
  15. MiG-23MLD

    MiG-23MLD Major SENIOR MEMBER

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    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    S ducts also create air flow disturbances, in fact the reason Boeing and Sukhoi went for straight ducts has to do with efficiency and weight.

    Highly integrated airframe-propulsion systems featuring ingestion of the airframe
    boundary layer offer reduced noise, emissions, and fuel consumption. Embedded engine
    systems are envisioned which require boundary layer ingesting (BLI) serpentine
    inlets to provide the needed airflow to the engine. These inlets produce distorted flow
    profiles that can cause aeromechanical, stability, and performance changes in embedded
    engines.
    Proper design of embedded engine systems requires understanding of the
    underlying fluid dynamics that occur within serpentine inlets

    http://scholar.lib.vt.edu/theses/available/etd-12222011-143750/unrestricted/Ferrar_AM_T_2011.pdf


    Another facet of the study of flow in S-duct is flow control because these ducts find
    practical application as aircraft air-intake ducts. The trend in modern fighter aircraft is to
    have a short and highly curved S-shaped intake duct. The short length reduces the structural
    weight of the aircraft and increases the internal space packaging efficiency. However, the
    shortening of the duct results in a highly curved duct profile while still maintaining the
    correct offset of the engine fan face (housed in the fuselage) and the intake entrance face (at
    the exterior of the fuselage). Although the short intake duct is highly desirable for its
    compactness and weight reduction, it is aerodynamically inefficient, as it is highly susceptible
    to massive flow separation. In addition, the flow is coupled with bulk swirl with the presence
    of stream-wise vortices. These flow features lead to total pressure losses in the duct, flow
    distortion at the duct exit and hence flow non-uniformity at the engine fan face.
    ScholarBank@NUS: Terms of Use

    while is possible to design an efficient S duct, straight ducts are prefered


    The diffusing S-duct is a typical aircraft inlet geometry. It decelerates air entering the compressor and
    increases the static pressure. The Lockheed Matin F-16 has a chin-type S-duct and Korean advanced
    supersonic trainer T-50 has a bifurcated S-duct.
    A well designed diffusing S-duct can help to enhance engine performance by delivering a nearly
    uniform flow with a small transverse velocity component at the engine compressor entrance. But the
    centerline curvature associated with the S-duct makes a centrifugal force and cross-stream pressure
    gradient between the bottom and the top of S-duct.
    As a result the diffusing S-duct integrates the
    complex 3-dimensional internal flow which includes secondary flows and flow separation. Wellborn
    et al. [1] performed a compressible subsonic flow experiment through a representative S-duct
    configuration and investigated the complicated flow mechanism in detail. The baseline diffuser of our
    design corresponds to the experimental configuration of Wellborn et al.
    The aerodynamic performance of subsonic diffusers is principally determined by two
    parameters; the flow distortion at the outlet of the diffuser and the total pressure recovery. If the flow
    distortion is reduced and the total pressure recovery is close to one, it can be considered to be welldesigned.http://www.iccfd.org/iccfd7/assets/pdf/abstracts/ICCFD7-2401_abstract.pdf


    функцию сверхманевренности (Lockheed Martin F/A-22 Raptor: Stealth Fighter. Jay Miller. В качестве недостатков известного самолета можно указать следующее: - невозможность управления в каналах крена и рысканья при полете на малых - скоростях, поскольку двигатели расположены вплотную друг к другу, что не not позволяет создать достаточный для управления момент - расположение двигателей вплотную друг к другу делает невозможным - расположение в фюзеляже грузовых отсеков;изогнутая форма каналов воздухозаборников требует увеличения их длины, и, - следовательно, массы самолета

    feature super maneuverability (Lockheed Martin F/A-22 Raptor: Stealth Fighter. Jay Miller. 2005). In 2005).As a well-known disadvantages of the aircraft, you can specify the following: Inability to control the channels roll and yaw when flying at low speeds, because the engines are located close to each other, which does not allows you to create an adequate management time; The engines close to each other makes it impossible location in the fuselage cargo compartments; - Curved air intake duct requires an increase in their length, and; hence, the mass of the aircraft http://195.208.85.248/Archive/PAT/2012FULL/2012.01.27/DOC/RUNWC1/000/000/002/440/916/document.pdf

    Both the commercial and the military aircrafts generally use the S-ducts to deliver the captured flow from far field to the engine compressor. The engine efficiency is influenced by the intake performance remarkably. Therefore, an efficient inlet duct should be able to deliver uniform and high pressure-recovery flow to the engine face. From the structural and aerodynamic point of view, it is more effective the length of inlet is short. The short length of duct, however, needs high curvature of the duct and highly curved duct generates large separated flows.http://www.ksiam.org/conference/annual052/upfile/abstract_18.pdf

    In a previous paper the major design parameters were identified, which should be
    considered in the design of the curved turbojet intake. In that paper it was pointed out that the
    curved intake (Figure 1) air inlet that typically results in pressure drops could be overcome or
    designed to become significantly small or non-existent for all practical purposeshttp://www.allaboutthrust.com/Design_Solutions_To_Curved_Air_Intake_(5).pdf
     
    Last edited: Sep 27, 2012

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