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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. Picard

    Picard Lt. Colonel RESEARCHER

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    As far as SAMs are concerned, there are VHF radars and multistatic radars (which can be both active and passive).
     
  2. MiG-23MLD

    MiG-23MLD Major SENIOR MEMBER

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    [​IMG][​IMG]

    is it real? perhaps it is

    but who cares if this works well


    [​IMG]

    With its passive radar, Cassidian is focussing on the requirements of civil and military airspace control which until now could not or not sufficiently be met using active emitting radar. In civil application, passive radar makes cost-effective air traffic control possible without any additional emissions and without making demands on transmission frequencies in short supply. In military applications, the system enables large-area surveillance using networked receivers, while offering the decisive operational advantage that passive radar cannot be located by hostile forces. The particular characteristics of the omnipresent radio signals used for operation enable detection of even objects that are difficult to detect, such as stealth aircraft or stealth ships. A further advantage of the new technology is its increased detection capacity in areas of radar shadow such as mountainous terrain and its capability to locate extremely slow and low flying objects. http://rpdefense.over-blog.com/article-passive-radar-from-cassidian-remains-invisible-108321249.html
     
    Last edited: Sep 16, 2012
  3. Averageamerican

    Averageamerican Colonel ELITE MEMBER

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    Well lets see if I got this figured out about right, it took India 38 years to build the Tejas (using american engines)which is about equal to the F16 that the USA was building over 40 years. Now according to you all China is so far advanced beyond India they can build the J20 5th Generation Fighter which is superior to the F22 and F35.
    Does that about cover it.?

    India orders 99 GE F414 engines for Tejas fighter jet | GE Reports
     
  4. gambit

    gambit FULL MEMBER

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    You have the basic understanding right.

    Believe it or not -- incorrect.

    [​IMG]

    That is a close up of a part of the F-117.

    How many surface discontinuities can you count? Keep in mind that a bent plate have one additional EM radiator -- the bent itself. The reason why the F-117 and the F-22 may have similar RCS -- and am not going into specific numbers -- is that we are looking at the mono-static radar configuration.

    A mono-static radar is the 99% dominant system in the world. A mono-static radar is where one antenna does both transmit and receive functions.

    [​IMG]

    A bi-static configuration is where there are at least one physically distinct receiver. For the example above, B will receive the most reflection, A will receive less, and if the Transmitter itself receive any reflection going its way, it will receive the least. That is why the F-117 with its many surface discontinuities will be the superior RCS radiator than the F-22 against a bi-static radar system. For the F-22 with its curvatures with far less surface discontinuities, Receiver B will be the one to pick up the aircraft, Receiver A is probably just as useless as Transmitter/Receiver.

    Each triangle is called the 'bi-static triangle'...

    Bistatic radar noncooperative illumination synchronization techniques
    ...With the 90 deg the best for any ground station. Unfortunately, we are dealing with a moving target so this preferable position is statistically useless. The only solution is to have more stations, each one will have a brief moment of detection, communicate with the other stations, and the 'stealth' aircraft can be tracked this way. So while technically speaking, the bi-static radar is 'stealth' greatest threat, it is a resource intensive system to develop and deploy. To date, no one have any that can realistically defeat 'stealth'.

    To sum it up, the F-117 is a superior EM radiator than the F-22 because of its greater quantity of surface discontinuities. But against a mono-static adversary, which is 99% of the world's radar systems out there, but aircraft are equal in terms of detectability.

    Clear as mud?
     
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  5. gambit

    gambit FULL MEMBER

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    People,

    No such beast as a 'passive radar'.

    Radar detection is a two-part process: Transmission and Reception (of reflections).

    The ideal situation is that both parts are under the control of a single owner/operator. A bi-static system is like a mono-static system in that respect.

    What is the misnomer 'passive radar' is when the Transmission part is NOT under the control of the owner/operator. He must rely on 'opportunistic' transmissions from elsewhere, such as radio, TV, and so on...

    [​IMG]

    So what happens if the city's electrical power is degraded or even destroyed? If degraded, then there will be gaps in transmission coverage where the 'passive radar' will be useless. If destroyed, then the 'passive radar' are completely useless.
     
  6. Gessler

    Gessler BANNED BANNED

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    Hmm...so the stealthiest fighter would be one that is shaped like a flying saucer with the least possible
    number of EM radiators.
     
  7. MiG-23MLD

    MiG-23MLD Major SENIOR MEMBER

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    [​IMG][​IMG][​IMG]

    likely engine RD-93

    [​IMG]
     
    Last edited: Sep 16, 2012
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  8. Gessler

    Gessler BANNED BANNED

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    ^^ Why does this one have a framed canopy when J-20 already has a frameless one?
     
  9. neil_diablos

    neil_diablos Lieutenant SENIOR MEMBER

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    Not sure what the Tejas has got to do with J20 discussion, but maybe your unparalleled super brain has deduced something which we normal people cannot comprehend.

    Yes that just about covers it, except that ANY fighter would be superior to the F22, given that the F22 is too advanced and too precious to fly in any combat. Even if it does manage to fly, the pilots would probably be busy fighting to stay conscious rather engaging any hostiles.

    As far as the F35 is concerned, well I guess even an F4 C can turn it into mincemeat given that the F35 "can't climb", "can't turn", "can't run"!

    Finally am glad you see the reality.
     
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  10. smestarz

    smestarz Lt. Colonel REGISTERED

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  11. neil_diablos

    neil_diablos Lieutenant SENIOR MEMBER

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    Yes, this fighter cannot be the J20. In all probability, The Chinese used the F22 data that they stole, to build this fighter. Chinese military programs are extremely seceretive. God knows what next they have up their sleeves. In any case, Chinese military build up definitely is a cause of concerns for the Americans or for that matter even us. I'll feel better when the first prototype of the FGFA is up and flying.
     
    Last edited: Sep 16, 2012
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  12. Picard

    Picard Lt. Colonel RESEARCHER

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    I'll feel best when Swedes put IRST into Saab Gripen C and stop weight/size increases.
     
  13. Vritra

    Vritra Major ELITE MEMBER

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    31001- Gotta be the first prototype of whatever it is. Anyone else remember "leaked" pictures on the Chinese web, showing an aircraft under a tarp in transit to somewhere? Rumours were abound that day that it resembled the prototype revealed a year or so before:

    [​IMG]

    Its hard to tell from current pictures, but apart from the different intakes, they look pretty damn similar to that^^^.
     
  14. SpArK

    SpArK SorCeroR Staff Member ADMINISTRATOR

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    Also double canopy glass is different.
     
  15. G777

    G777 Lt. Colonel ELITE MEMBER

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    Looks like India's future fighter aircraft have got a big challenge ahead of them.

    China really likes copying aircraft. I see a lot of similarities to the F35, even on the J20, however I also see some tweaks that they have made. This could be very interesting. :respect:

    Look at the nose on this image:

    [​IMG]

    A bit early to tell but it looks like a pentagon shape, even less rounded areas.
     

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