• Sunday, August 25, 2019

F-22 vs J-20 - aka USA-made jet fighters vs China-made jet fighters

Discussion in 'Chinese Defence Forum' started by samsara, Jul 3, 2018.

  1. Akasa

    Akasa SENIOR MEMBER

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    Such as when they claimed that they defeated the RAF 12:0 during joint exercises? Come on now, this is getting ridiculous.

    Please explain how IAF radar was able to distinguish an aircraft with Luneburg lens from one without.

    I'd like to see photograph/satellite evidence that the J-20s have been operationally deployed to the Sino-Tibetan border. So far users and observers have been pretty good with following up on the deployment of J-20 units, but so far nothing has come up in the Tibet region.

    All the more reason to dismiss those claims rather than to take them seriously.
     
  2. gambit

    gambit PROFESSIONAL

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    Because you were.

    You were correct in that in radar detection, the target's RCS value and signature are largely unknown, which made this statement correct...

    "I'm saying you don't need to know what it's radar signature to design a counter systems,..."

    But you were also incorrect with that statement in that since each shape is unique it means that given the variations of a shape, all members of that group bears the same basic signature.

    For example...

    [​IMG]

    Which of the above pair would have similar RCS signature? Definitely not the second pair.

    For the first pair, their foundation is the cube shape. There are four sides -- flat plates -- which means high specular reflections. For the second cube, its rounded edges means no edge diffractions, which means lower radar returns. So if we rotate both cubes, does not matter which speed and angle, the rounded cube would have a lower RCS overall, but both cubes would resonate with the regular incidences of high specular reflections precisely because of the four flat plates. This similarity would help identifying both bodies as being of the cube family.

    All airliners have the same RCS signature, but not all fighters. On the other hand, fighters that have large delta wings like the Typhoon, Vigen, and Rafale WILL exhibit similar RCS signature at every radar aspect, most commonly the top and bottom views. These are the laws of physics that not even China can defy. :lol:

    I doubt you read it, let alone understood it, because as your next comment revealed...

    My post about the MTI radar involved the Doppler component. Just because I did not insert the word 'Pulse' does not mean I do not know what I am talking about. The fact that you 'advised' me to read up on the PD radar means you did not read my response to your claim that extracting the Doppler component would be the easy way to counter 'stealth'. It is not, as I explained why FOUR YRS AGO. You are too late to the game. No serious minded and objective person on this forum argues that point anymore.

    For the readers out there, here is why, again...

    - Every radar system have a clutter rejection threshold, usually based upon amplitude per return. The clutter rejection process immediately filters out any signal that is BELOW this threshold.

    - This threshold can be lowered or even eliminated.

    So if there are one million signals out there, it is a signal processing issue. Not a problem, but an issue.

    A radar beam cannot process the entire visible area. Only a section at a time and that section is determined by the beam shape. So if there are one million signals, only a percentage, will be processed to filter out whatever criteria, which in this case is the Doppler component. The clutter rejection process filters out most, but now it is not used.

    With a large beam, it is a time processing issue, as in each signal must be analyzed and compared to other signals in the batch.

    With a small beam, it is a volume processing issue, as in volume of the sky to sweep.

    It boils down to this...

    CAPABILITIES
    FEATURES

    FUNCTIONALITY
    EFFICACY


    The last pair and with the last pair, it is the final half -- EFFICACY.

    So while technically possible, using the Doppler component of a return signal to counter 'stealth' is TACTICALLY INEFFICIENT. You talk as if somehow in this little corner of the Internet, counter-stealth was revealed and no one from Lockheed and the USAF worked out the many possible scenarios in all these decades. We 'forgot' about the Doppler component of the return signal. :lol:

    You are an average Chinese PDF member in the sense that you do not read the responses to your arguments and the sources you brought on from your googlling.
     
    Last edited: Jul 9, 2018
  3. pakistanipower

    pakistanipower ELITE MEMBER

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    Its not about JF-17 But J-20, How can your Sukhoi can detect/track/engage J-20 200 Km away @HariPrasad o_O which is 5th gen jet and claiming serious threat to US in western Pacific, admitted by US top brass, Pentagon @HariPrasad ;):):enjoy:
     
  4. Chinese Commie

    Chinese Commie FULL MEMBER

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    Even gambit don't dare to say I'm totally wrong on this topic. That's because he knows I'm right. I'm definitely correct that you don't need to know an aircraft radar signature to design a system to shoot it down.

    Radar signature really doesn't mean a lot. If you're unidentified, you'll get targeted.

    If they are at an imminent war, the security would already be on high alert. Anything will get shot down without normal warnings. And yes, in times of war, "you just indiscriminately shooting down EVERY radar contact you have." However, as I've said before, all civilians aircrafts are required to have transponders and to identify themselves, if not they will get shot down. This protocol is common elsewhere in the world.

    Comparing i5 and i7 is like comparing an advanced trainer to a fighter. Why are you doing this? Again, We're reaching the limits of Moore's Law, but if you look at the trend in the past, Moore's Law has always been right. Also, if it's not right, why would every make a big deal out of it? The trend is there for you to see in the graph I've provided you. It's clear as day, if you're still refusing it, I'm really just wasting my time.
    At least gambit has real knowledge and he doesn't argue against facts, that I can deal with. lmao

    How can I not compare? The point is you can study many stuff such as the stealth coating used on the aircraft even from wreckages. Ok you want better comparison?

    " It’s similar to the MiG-15, in that we were looking at modeling and simulations, and developed threat assessments long before we got our hands on one.” During the Korean War, NASIC’s predecessor, the Air Technical Intelligence Center, recovered parts of crashed MiG-15s and studied the wreckage to learn more about that game-changing MiG’s performance." (airspacemag)

    I really don't know why I have to spend so much time finding quotes to proof my points, which are relatively common sense. And to think that I started getting into this stuff years after you.

    Please explain how does "since each shape is unique it means that given the variations of a shape, all members of that group bears the same basic signature." won't allow the Chinese to design an AA system against stealth aircraft? Because that's the whole point of my statement.

    Oh yes I read it, I read a whole college lecture presentation on MTI radars on this, and many articles and forums just to come refute you. I did way more research than I even have to just to make sure I'm correct. lmao

    I've provided you the quote from a reputable source to refute your claim, did you read it?

    "So while technically possible, using the Doppler component of a return signal to counter 'stealth' is TACTICALLY INEFFICIENT." Great, I'm correct then that speed is is a discriminator for radar detection, especially when you get a more advanced radar that does Pulse Doppler processing. And as my source have also said, MTI does work. Im satisfied. I'm sure they have way better technologies now, I'm simply an military enthusiast and what's on the internet is what I have to work with.

    My quotes refute your argument, I'm sorry you don't like it.
     
  5. pakistanipower

    pakistanipower ELITE MEMBER

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    And you don't know what is you talking about @Okarus , you arguing with professional without base, @gambit and @jhungary which knows better defense matters/concepts than you and me, And as for Moore's law is not related to military tech but toward civilian tech @Okarus :hitwall::crazy::hitwall:
     
  6. Chinese Commie

    Chinese Commie FULL MEMBER

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    Care to explain how a principle that governs all electronics does not have to do with J-20's radar? Can you explain why it's not applicable, because if you can't then it's better than your words without any proof or principles.

    I didn't even used the word 'superior'. Go back and read.

    If you're not gonna refute my points please don't make unnecessary comments, because I do read all of them and they're just wasting my time.

    I'm not professional. However I've made many good points, an refute many of gambit and jhugary's claims Am I wrong? Who are you to say that it is not related to military tech and just civilian tech? Please provide logical arguments.

    I've spend this much time researching and debating, because I know I'm not wrong, and I am simply standing up for myself. Gambit said "MTI does not work", I provided a quote from a reputable defense contractor that says it works. Now he's walking back on his statement and simply say that using these kinds of method to assess speed is "tactically inefficient." Are you saying I should not do this?
     
    Last edited: Jul 9, 2018
  7. pakistanipower

    pakistanipower ELITE MEMBER

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    What good points i seen your debate to @gambit and @jhungary from the beginning, you haven't single good point @Okarus


    every think we have use to i mean especially electronics and its big items develop and tested by military before its enter the civilian markets prime examples were ENAAC the first computer develop by USA in 1941 to predict German BM trajectories of the world war 2 & Boeing 747 which was first contested of LM design and become most successful airliner of the world & GPS originally designed for US armed forces but later used by civilian companies and individuals @Okarus
     
  8. Chinese Commie

    Chinese Commie FULL MEMBER

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    Oh haha I've made a lot of points they can't refute, those are what I think as "good". They've been trying to say I'm wrong, but without substance, hence "partially wrong". But these are simply for my personal entertainment. You can think whatever you want.

    Here let me use gambit's words to refute your argument.

    The point is military and civilian market constantly exchanges technologies and they are not far from each other. In some areas, military might have more advanced technologies, but for some areas the civilian markets also have more advanced (more mature) technologies. Good point?
     
  9. pakistanipower

    pakistanipower ELITE MEMBER

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    you all wrong Military departments of the world want a tech far more better/finer than civilian sector, if even military want civilian tech infact they quite different from those civilian tech, base tech for civilian sector/ standards had been developed by defense departments/agencies of 50s, 60s, 70s and 80s @Okarus
     
  10. Yaseen1

    Yaseen1 SENIOR MEMBER

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    u.s did mistake by choosing f22 over f23 as 5 gen plane due to lower cost.f23 would have given more superiority to u.s over rivals
     
  11. gambit

    gambit PROFESSIONAL

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    You have 'refuted' nothing of my responses to you, and I have not 'walked back' any statement. When I said the MTI method does not work, I meant it in the context of what people claimed that the method WOULD be a viable tactic against low radar observable platforms. So far, you managed to dredge up one OPINION, not anything remotely like an experiment that could serve as a foundation for a future defense method.
     
  12. randomradio

    randomradio BANNED

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    Strictly speaking, the IAF was never quoted saying that. It was written by Vishnu Som, an extremely important person in the news media in the country.

    Radars see hotspots. It's easy to see if the radiation is coming in from hotspots or from the Luneburg lens.

    You can see the returns from different parts of the aircraft here:
    [​IMG]

    Just look at page 4.
    [​IMG]

    If the J-20 had Luneburg lens on, it's easily identifiable.

    Plus, unlike most air forces, our pilots are trained EW officers as well, not to mention the MKI almost always has the WSO with more than a decades worth of experience.

    Detachments always fly out to different places. It's part of the training regimen also. So it's not necessary for an aircraft to be stuck within its home base.

    Not to mention, India is China's biggest threat because we are the only country around with the army capable of invading China. It's obvious J-20 will be tested against our systems.

    Not really. That's the Air Chief there, not some random guy.
     
  13. Chinese Commie

    Chinese Commie FULL MEMBER

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    Tell that to @gambit

    Gambit is right that most hardwares and technologies already existed and tested in civilians market. The cutting edge technologies you hear so much is just a part of the big picture. Those little components and hardware technologies still come from civilians markets.

    Hey, and why are you telling that I'm all wrong when I'm simply using gambits words to refute your argument.

    How am I supposed to know what context you're talking about? I was saying that speed is a compromising factor, and it is (my source agreed). You brought up the rather irrelevant MTI radars yourself.

    Moore's Law is based on observed trend of all electronics and it's widely accepted as the prevailing principle in the electronics industry. To base military advancement on this law is my opinion, and it's an opinion that no one has yet to able to refute with substance and say why would military electronics won't follow it.

    Here I'll give you an article from phys.org to further clarify what Moore's Law really entails

    "
    Moore's Law has been a great blessing to science and mathematics research. Modern laboratories are loaded with high-tech measurement and analysis devices, which become more powerful and cheaper ever year.

    In addition, a broad range of modern science, mathematics and engineering has benefited from Moore's Law in the form of scientific supercomputers, which are used for applications as diverse as supernova simulation and protein folding to product design and the processing of microwave background radiation from the cosmos.

    Software running these computers has advanced abreast with Moore's Law.

    For example, the fast Fourier transform algorithm, which is used extensively in scientific computation, and magnetic resonance imaging (MRI), both involve substantial computation that would not be possible without Moore's Law advances.

    It is not entirely coincidental that both of these algorithmic advances arose roughly 50 years ago, the same time Moore's Law was first observed.



    Read more at: https://phys.org/news/2015-07-law-years.html#jCp"
     
  14. gambit

    gambit PROFESSIONAL

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    This is proof that even though you read, you did not understand.

    An RCS value is not the same thing as an RCS signature.

    Look at this illustration again...And try to spend more than just one second at it...

    [​IMG]

    A 'signature' is unique in the sense that it contains features that nothing else has, whereas a value is just a numerical assignment.

    Look at it this way...

    Two men have the same name of 'John Smith', but would their handwritten signatures be exact? No. The value of their common name would be the same of 4 for 'John' and 5 for 'Smith'. But it would take an expert forger to sign their names exactly the same way.

    So you did not understand what I responded to you. I did not say it "won't allow". In fact, I gave you the clue as to how signatures WOULD -- not could -- be used as a viable counter-stealth method. I said: "All airliners have the same RCS signature, but not all fighters. On the other hand, fighters that have large delta wings like the Typhoon, Vigen, and Rafale WILL exhibit similar RCS signature at every radar aspect, most commonly the top and bottom views."

    You gave an overly broad claim in post 46 pge 4: "so I'm saying you don't need to know what it's radar signature to design a counter systems,..."

    I gave you an explanation on why an RCS signature, not an RCS value, is needed.

    I understood it better than you have and can. But did you understood what I said about beam width and how much a radar can process at any moment? Guess not since you are still harping on the buzz words 'Pulse Doppler' and quoting someone from quora.com.
     
  15. pakistanipower

    pakistanipower ELITE MEMBER

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    OTE]
    Hi don't twist your words, I continuously following your and @gambit debates @gambit didn't said ahow me his post number or copy paste his post @Okarus