J-20 5th Gen Fighter Thread IV (Closed to posting)

[Skywatcher]

You constantly try to portray that last few percentages to be a world of difference, but 5~10% is just that -- 5~10%. It means any error in estimating material properties by Chinese engineers only causes a 5~10% deviation. If the engineers underestimated the effect of RAM by half, then the model would still be 95~97.5% accurate. If the engineers got the estimation of the material effects right by 80%, than the estimation would be 98~99% accurate. That is why your argument doesn't work.

Let's use your math and assume that shaping reduces the RCS of a F-22 to 0.5m2.

Now assume a baseball sized target, which gives us a RCS of 0.01m2. But if you underestimated the RAM effect, you get 0.25m2.

Now, is a 0.01m2 target at BVR more dangerous than 0.25m2?

Strawman argument. No one ever claimed that the RAM on the F-22 is the exact same as that on the J-20, or that the 093B powerplant is the exact the same as the LA class's. Estimating RCS involves taking the country's existing knowledge of how stealth works, then applying them in a way to figure out how well the other guy's stuffs work.

Ahem, it's not a strawman when you were whining that "simple physics" would allow "You can absolutely predict how the other guy's technology will behave".

You can't have it both ways. That's like saying Han Chinese are genetically unique from all other Asians when regional subsets of Han population have more in common with Koreans or Taiwanese aborigines than Han Chinese at the other end of China

The need for perfect details is an invention made by you. There is no such requirement in the real world.

You need a more complex understanding for a more complex model. I haven't asked for perfect details, but you need more complexity than the simple "build a metal mockup with approximate RAM" fanboy hype.

Nope. Figuring out the RCS only requires application of one's scientific and practical implementation knowledge in stealth technologies to the exterior. It does not concern with the interactions among subsystems. There is no also need for a physical copy to exist for diss-assembly, copied, then have a perfect replica produced before any knowledge can be gained. See post #1874.

I didn't say perfect replica, but it must be a complex model if you wish to understand a complex system.

I will take this as your concession.

 

[Skywatcher]

Fifth generation fighters are indeed complicate, which is why only three countries in the world can realize them. China being one of those countries, and so has the abilities to figure out the RCS of a fifth generation fighter.

It takes a lot work to figure out the RCS of a fifth generation fighter, like other complex modern systems, because you simply have less room for error.

 

[rhino123]

Please enlighten me on this matter... why is there the obsession of getting extremely accurate information on US F-22 and F-35 RCS by China... so much so that there are suggestion of cyber episonage, reverse engineering, etc etc? And why was it only China doing that (or so it seemed after so many threads on this issue?)

Doesn't the US want the RCS of China's J-20, J-31 and Russia's T-50 too? And if so, how would the US go about it? if accuracy was to be so precise, then wouldn't the US also face the same problem as China in trying to reverse engineered or getting the same data as China?

So... if the US is able to do it (I am not suggesting that they could, just a simple assumption), then how did they manage to do it? Was it that the US just gotten their hand on information on the net, and by their own estimation to get a rough idea of China's J-20's RCS, or did they actually gotten hand on vital information such as dimension, shape, angle, RAM etc from some sources (can be cyber episonage or spy, or whatever), and if US didn't did that, and just gotten the information by estimation (which might not be too accurate), then why did everyone think that the Chinese need to be 100% accurate on this issue too?

 

[kwaigonegin]

Please enlighten me on this matter... why is there the obsession of getting extremely accurate information on US F-22 and F-35 RCS by China... so much so that there are suggestion of cyber episonage, reverse engineering, etc etc? And why was it only China doing that (or so it seemed after so many threads on this issue?)

Doesn't the US want the RCS of China's J-20, J-31 and Russia's T-50 too? And if so, how would the US go about it? if accuracy was to be so precise, then wouldn't the US also face the same problem as China in trying to reverse engineered or getting the same data as China?

So... if the US is able to do it (I am not suggesting that they could, just a simple assumption), then how did they manage to do it? Was it that the US just gotten their hand on information on the net, and by their own estimation to get a rough idea of China's J-20's RCS, or did they actually gotten hand on vital information such as dimension, shape, angle, RAM etc from some sources (can be cyber episonage or spy, or whatever), and if US didn't did that, and just gotten the information by estimation (which might not be too accurate), then why did everyone think that the Chinese need to be 100% accurate on this issue too?

I doubt the US knows the exact RCS of the J-20 however they may not need to since American aviation industry is much more mature and established than anyone else and so is the C4ISR and detection, AEW type capabilities etc.

Since the US is already ahead in the 'RCS race' all they need to do is to test their equipment against their current inventory.
Odds are if the US have sensors and radar that can detect and track F-22 it can probably do the same for J-20 and PAK-FA. If not then you better set your goals to tracking the Raptor and NOT the J-20 or PAKFA.

Is akin to you already owning a Ferarri do you really need to know how fast your neighbor's brand new BMW is other than just for academic purposes? he OTOH needs to know how fast yours can go so he can work on his car till parity or at least close to it. By then hopefully you would've graduated to a Bugatti.

 

[rhino123]

I doubt the US knows the exact RCS of the J-20 however they may not need to since American aviation industry is much more mature and established than anyone else and so is the C4ISR and detection, AEW type capabilities etc.

Since the US is already ahead in the 'RCS race' all they need to do is to test their equipment against their current inventory.
Odds are if the US have sensors and radar that can detect and track F-22 it can probably do the same for J-20 and PAK-FA. If not then you better set your goals to tracking the Raptor and NOT the J-20 or PAKFA.

Is akin to you already owning a Ferarri do you really need to know how fast your neighbor's brand new BMW is other than just for academic purposes? he OTOH needs to know how fast yours can go so he can work on his car till parity or at least close to it. By then hopefully you would've graduated to a Bugatti.

Agreed with your assessment. However, wouldn't it be equally important for US to actually know what they are up against during an air battle?

Say... even if person A had a ferarri in his backyard which he used it to race with his neighbour, whom up till now owns a BMW. However, he wouldn't really know if the neighbour only owned that BMW or if the neighbour actually do something to that BMW till it can match the speed of a ferrari. Sure, the heavily modified BMW might not be as good as an actual Ferrari, but without knowing its actual capability, Person A might be in for a big shock when the actual day of racing came about.

 

[kwaigonegin]

Agreed with your assessment. However, wouldn't it be equally important for US to actually know what they are up against during an air battle?

Say... even if person A had a ferarri in his backyard which he used it to race with his neighbour, whom up till now owns a BMW. However, he wouldn't really know if the neighbour only owned that BMW or if the neighbour actually do something to that BMW till it can match the speed of a ferrari. Sure, the heavily modified BMW might not be as good as an actual Ferrari, but without knowing its actual capability, Person A might be in for a big shock when the actual day of racing came about.

true also however at this point in time I think it's quite a safe bet to assume that the neighbor's BMW (J-20) is stock. Not only is it stock but it hasn't even gotten the plates yet to properly drive on the streets (IOC).
I'm sure the day will come where the J-20 will have WS-15, TVC and all that but by then the US will most likely know a LOT more about the J-20.

Basically what I am saying is at this very moment in time, it's not as crucial for the US to know the exact RCS of the J-20 than it is for China, Russia etc to know the RCS of the F-22.

 

[HKSDU]

weapons bay

 

[Quickie]

Armature or amatuer?

 

[Deino]

...

weapons bay

Yeppp ... I posted this already yesterday (much smaller ) but was this a recent or an older image ??

Deino

 

[Deino]

Maybe or not baby !??

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