Chengdu next gen combat aircraft (?J-36) thread

[Cloud_Nine_]

Tbf that's kind of the point of OTH. Ofc OTH will be able to detect VLO platforms as J-36 and B-21 easily. But OTH will only tell you "something is here, roughly, go figure".

As for RCS against notional S & X wave radars and VHF radars, there's a giant elephant in the room: they're only mapping out frontal RCS... One of the key evolutionary advantages of a sixth-gen is being stealthy all around and not just frontally.

If we are extraordinarily generous and take their numbers at face value, this still doesn't make or break what J-36 is. My point is, we already know with reasonable certainty that sixth gen platforms aren't suddenly magical radio wave blackholes. I don't think their point is to say J-36 isn't stealthy.

And they're ignoring basically ALL the other areas that make sixth-gen stealthy to fifth-gen. J-36 has afawk: one giant nose radar, 2 side radars, and 4 giant optical sensors. 6 out of the 7 sensors being installed on the side of the aircraft is a good indication that J-36 probably doesn't care as much if the engagement is head-on or not. The same cannot be said for J-20 or F-35.

"There is no magic in this world and even military projects need to follow physics."

So I guess their point is just to show that J-36 doesn't have a revolutionary advantage in frontal RCS compared to a typical fifth-gen platform...? I mean... sure? LOL. We don't need to have a visceral reaction to this post or anything. It's like they're just saying J-36 can still be detected because there is no 100% stealth. Well.. yeah.. no sh*t sherlock...

 

[siegecrossbow]

Tbf that's kind of the point of OTH. Ofc OTH will be able to detect VLO platforms as J-36 and B-21 easily. But OTH will only tell you "something is here, roughly, go figure".

As for RCS against notional S & X wave radars and VHF radars, there's a giant elephant in the room: they're only mapping out frontal RCS... One of the key evolutionary advantages of a sixth-gen is being stealthy all around and not just frontally.

If we are extraordinarily generous and take their numbers at face value, this still doesn't make or break what J-36 is. My point is, we already know with reasonable certainty that sixth gen platforms aren't suddenly magical radio wave blackholes. I don't think their point is to say J-36 isn't stealthy.

And they're ignoring basically ALL the other areas that make sixth-gen stealthy to fifth-gen. J-36 has afawk: one giant nose radar, 2 side radars, and 4 giant optical sensors. 6 out of the 7 sensors being installed on the side of the aircraft is a good indication that J-36 probably doesn't care as much if the engagement is head-on or not. The same cannot be said for J-20 or F-35.

"There is no magic in this world and even military projects need to follow physics."

So I guess their point is just to show that J-36 doesn't have a revolutionary advantage in frontal RCS compared to a typical fifth-gen platform...? I mean... sure? LOL. We don't need to have a visceral reaction to this post or anything. It's like they're just saying J-36 can still be detected because there is no 100% stealth. Well.. yeah.. no sh*t sherlock...

Frontally it still will be better by the virtue of not having vertical slabs. Frontal doesn’t just mean dead head on you know.

 

[burritocannon]

people still mired in hollywood movie mentality of focusing on The Airplane as some kind of hero character instead of thinking in terms of a component in a greater system...

 

[Xiongmao]

View attachment 148072

J-36 is not super long, maybe 0.5 to 1 m longer than J-20. So when a tandem twin seat J20s is compared with it, it's obvious the canopy is much longer when in tandem configuration. Leading to the conclusion that the J-36 indeed does not likely have tandem seating. Which again leads to the strong possibility of side by side seating.

Even if one believes J-36 is 2-3 m longer than J20, the canopy length difference isn't that great, with the J20S one still being visibly longer.

How do you know that the J-36 is only about the same size as the J-20. The only claim to this was based on the video of the initial flight with the chase plane wasn't it? That seems to me like a totally unreliable way to deduce the length of the J-36. The perspective and altitudes of the two planes could make the J-36 appear the same size as the J-20 but in fact could be much bigger. As big in fact as if you were to magnify your top picture so that the canopy of the J-36 becomes the same length as that on the J-20S.

 

[Cloud_Nine_]

Frontally it still will be better by the virtue of not having vertical slabs. Frontal doesn’t just mean dead head on you know.

I know I was just being as generous as I possibly can to that author.

 

[00CuriousObserver]

Tbf that's kind of the point of OTH. Ofc OTH will be able to detect VLO platforms as J-36 and B-21 easily. But OTH will only tell you "something is here, roughly, go figure".

As for RCS against notional S & X wave radars and VHF radars, there's a giant elephant in the room: they're only mapping out frontal RCS... One of the key evolutionary advantages of a sixth-gen is being stealthy all around and not just frontally.

If we are extraordinarily generous and take their numbers at face value, this still doesn't make or break what J-36 is. My point is, we already know with reasonable certainty that sixth gen platforms aren't suddenly magical radio wave blackholes. I don't think their point is to say J-36 isn't stealthy.

And they're ignoring basically ALL the other areas that make sixth-gen stealthy to fifth-gen. J-36 has afawk: one giant nose radar, 2 side radars, and 4 giant optical sensors. 6 out of the 7 sensors being installed on the side of the aircraft is a good indication that J-36 probably doesn't care as much if the engagement is head-on or not. The same cannot be said for J-20 or F-35.

"There is no magic in this world and even military projects need to follow physics."

So I guess their point is just to show that J-36 doesn't have a revolutionary advantage in frontal RCS compared to a typical fifth-gen platform...? I mean... sure? LOL. We don't need to have a visceral reaction to this post or anything. It's like they're just saying J-36 can still be detected because there is no 100% stealth. Well.. yeah.. no sh*t sherlock...

Thanks for the comment. This is the kind of ””抛砖引玉““ I was hoping for.

 

[Stealthflanker]

Someone wrote a post on the RCS of J-36-like planes

EN:

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CN:

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Now I know talks on RCS should be taken with a huge grain of salt, but I'm wondering if there's any potential for a point here, as this person claims to know a lot about planes and radars.





@Stealthflanker ?

Same guy in Zhihu i think. The one which referred by an anti PLA account as "designers". Unfortunately beyond what he showed in his Zhihu thread or that website, not much can be gleaned about his methodology. Also no Radar absorber specification provided, so can't really compare.

His Zhihu thread :

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One thing i notice is the insistence in MOM (Methods of Moments) Which is correct an industry standard, for RCS modeling BUT only when your object is like 10 times smaller than the wavelength, the bigger the object the more intensive the computational needed, thus you might not or rarely see people using MOM to do a large airplane, or maybe at least he/she would do at narrow range of frequency. For some rapid design optimizations or even "the first cut" for conceptual and preliminary design other solvers like SBR+ or even simple PO is sufficient.

One example, this compares MLFMM a deriviative of MOM technique with SBR implementation.

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Which show reasonable result.

Also not sure why the person mention "how easy" it is the plane can be detected by Beyond the Horizon radar, considering that to counter the wavelength shaping and materials are impractical. One have to actually resort to active cancellation.

 

[by78]

This is almost artistic.

 

[Cloud_Nine_]

This is almost artistic.

 

[by78]

Someone wrote a post on the RCS of J-36-like planes

EN:

Please, Log in or Register to view URLs content!

CN:

Please, Log in or Register to view URLs content!

Now I know talks on RCS should be taken with a huge grain of salt, but I'm wondering if there's any potential for a point here, as this person claims to know a lot about planes and radars.





@Stealthflanker ?

Please stop posting amateur RCS analysis of an airframe that we don't even have a clear image of. In fact, don't post anything RCS related regarding any of China's stealth birds unless it's from an official source, such as academic papers. By the way, I don't understand why you're asking @Stealthflanker for opinions. He's demonstrably not an expert at anything I'm aware of, as evidenced by the exchanges seen here and here. Please keep content and interactions from pretend-experts away from the flagship threads.