J-20 5th Generation Fighter VII


tphuang

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Wouldn’t read too much into these models.
right, this is just something for us amateurs to get a sense of RCS of these aircraft a little better. The modeling themselves are not perfect and we really have no idea of how good the stealth layers are. Also, doesn't consider emission control and things like that. I do find it interesting that F-35 appears to be emphasizing the angles directly facing it more than J-20 is.
 

ZeEa5KPul

Major
Registered Member
Wouldn’t read too much into these models.
Just to drive the point home further, compare these two images
front.png

and
Chinese-Military-Strategy.jpg
The model bears a vague resemblance to the aircraft we've come to know and love as the J-20, but vague resemblance is about where it ends. Just as an example, the ventral strakes connect to the body completely wrong on the model, and if something that obvious is wrong then one shouldn't trust any of the fine details. Everything about it looks off.
 

phrozenflame

Junior Member
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btw, someone did a lot work in RCS analysis of j-20. Keep in mind these figures are posted without considering the RAM layer. He clearly stated how he did the simulation, so you can make your own judgement of these things
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Here is the end result of J-20 in his simulation
j-20-clean-with-mnzn-ram.png

vs F-35
f-35clean-with-mnzn-ram-1.png

Based on his analysis, you'd see that average RCS of J-20 faired the worst vs F-35A at X-band. From VHF to L band, the numbers look quite comparable. It seems like F-35A is also very much focused on just S to X band radar directly in front of its nose. Its stealth gets a lot worse as frequency decreases and angles are further away from the center.
I had been recently bugging him to do the analysis. Some of his other work is quite interesting. Anyway, it's something useful that we will find in public domain. Ofcourse it isn't perfect but if anyone got better analysis they should raise their hands.
 

Blitzo

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I had been recently bugging him to do the analysis. Some of his other work is quite interesting. Anyway, it's something useful that we will find in public domain. Ofcourse it isn't perfect but if anyone got better analysis they should raise their hands.

I think that while they numbers are certainly is not representative of the real world aircraft, the efforts taken by the author to do so can still be appreciated.
 

latenlazy

Brigadier
the number maybe inaccurate, but should represent some level of truth, i general take it as J-20 has roughly same level of steath level as F-35, and Su-57, despite it's the worst, but not as horrible as i thought
I think in general there's some value with this kind of exercise, but where I hesitate to go as far as "represent some level of truth" is that 1) accuracy of simulations are going to be pretty sensitive to model roughness, 2) as stealth materials and modeling has gotten better general shaping has become less deterministic in assessing RCS capability. It's still the principal factor, but it accounts for less than it used to.
I think that while they numbers are certainly is not representative of the real world aircraft, the efforts taken by the author to do so can still be appreciated.
Yeah I don't think the effort itself should be dinged. Just cautioning how people choose to interpret it.
 

stannislas

Junior Member
Registered Member
I think in general there's some value with this kind of exercise, but where I hesitate to go as far as "represent some level of truth" is that 1) accuracy of simulations are going to be pretty sensitive to model roughness, 2) as stealth materials and modeling has gotten better general shaping has become less deterministic in assessing RCS capability. It's still the principal factor, but it accounts for less than it used to.
Well, the thing is that we will never know the true RCS, none of the US, China and Russia would give out the RCS in details figures instead a rough number, and in compare with those numbers, this works definately represent more 'level of truth'. Like the very early AU work, some details like the reflection angles and the comparision results between Case 1 and 2 means more than just a RCS number, we may even get some kind of conclusion that J-20 performs better in long range with radar search mode, whereas F-35 does better against short range 'staring' mode.

Also, things like roughness or craftsmanship may not even able to be modelled in reality due the complexitiness, but that doesn't mean there is no value or 'truth value' of a model, in fact building a model is common in almost every science and engineering branchs. There are numoerious cases that important variables could not be modelled but instead using a number of experience to estimate. That's why I said:
J-20 has roughly same level of steath level as F-35, and Su-57, despite it's the worst, but not as horrible as i thought
you can take it further as, ok, F-35 probabaly has the best craftsmanship, so RCS would more close to this number, J-20 may be slight worse, so give a let's say 5% penaty, Su-57 has a visiable fan blade and tones of uneven screws, let's penalize it even more. Despite this would eveantually become a judgemental call, but at least give us a base line on how to evaluate the case, and this the value or the truth of this work.
 
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BoraTas

Senior Member
Registered Member
btw, someone did a lot work in RCS analysis of j-20. Keep in mind these figures are posted without considering the RAM layer. He clearly stated how he did the simulation, so you can make your own judgement of these things
Please, Log in or Register to view URLs content!
Here is the end result of J-20 in his simulation
j-20-clean-with-mnzn-ram.png

vs F-35
f-35clean-with-mnzn-ram-1.png

Based on his analysis, you'd see that average RCS of J-20 faired the worst vs F-35A at X-band. From VHF to L band, the numbers look quite comparable. It seems like F-35A is also very much focused on just S to X band radar directly in front of its nose. Its stealth gets a lot worse as frequency decreases and angles are further away from the center.
I think this is as close as we will get to true numbers as civilians for a while. He even modeled small body features like the antenna hump, complex things like the S-duct and non-specular effects. It is not really accurate for sure. To start with he doesn't model RAM. But this stuff is detailed and the software used is really powerful.
 

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