Don’t put too much stock in these models. They’re too coarse for the level of sensitivity that you would need to get any meaningful comparisons. When your model coarseness is an order of magnitude greater than the level of signal you’re trying to measure you’re not measuring anything.
J-20 5th Gen Fighter Thread VIII
- Thread starter Blitzo
- Start date
The truth is this kind of info is highly classified and there is no real way for you to find out. The people claiming they know should not be taken at face value. Scans are unreliable and even if they were reliable you have to consider that RAM coating is improving so depending on the exact production model things will be further different, etc. Bottom line trying to figure out RCS of J-20/F-35/F-22/Su-57 is kind of a fools errand, it's similar to trying to figure out exactly whose radar is more capable. The info is simply not in OSINT and there is no way for you to get that info.
Lets think what Stealth is. Its basically following the principle of a mirror. You reflect rays away from the sender by having angles that are never perpendicular. Consider taking Torch light in dark room and try to figure out a shape. That's kinda what Radar is doing.
You can basically eyeball stealth. Any planes with protruding shapes, multiple control surfaces will have higher RCS. J-20 loses stealth by having vertical stabilizers both on top and bottom. There are also overall shape alignment that seems a bit less compared to F-35. So, I think it can be reasonably guessed that J-20 has higher RCS.
The bottom stabilizers are made of composite materials only that are transparent to radar. The F-35 has all sorts of bulges and curves on its underside that are compromises made to enable carrying large diameter bombs, which is bad for stealth.
THIS!!! People often cite that one simulation from Aircraft 101, which IIRC assumed the strakes to be entirely metallic and didn't consider any sort of treatment and RAS to it. They in turn form massive corner reflectors with the cylindrical engine nacelles, when in reality the strakes are mostly RAS with two thin supporting beams, with the J-20A having them entirely made of RAS.
That simulation also assumed identical RAM across the F-35/Su-57/J-20, when in reality, you shouldn't even be sure just one kind of RAM is used on any of them. The model accuracy (barring the strakes problem already) is also on the iffy side.
Look, it's good effort, but it's terribly amateurish and serves close to no purpose in terms of real-world relevance. It's a borderline entertainment piece.
None of us would know exactly how they compare to each other. People online who claim any exact values with, say, the J-20 has an RCS of 0.01 m^2 while the F-22/35 is 0.0000000000001 m^2, they're bullcrapping (wrong unit too, in reality dBsm is the more "correct" unit).
The best you can do are vague inferences. In terms of stealth, there's absolutely no reason it shouldn't be as stealthy as the F-22/35. "Canards are bad for stealth" shouldn't even be a 2025 narrative.
As for the "J-20's stealth tech is based on the F-35," it's also bull. Off the top of my head, I think the Chinese use graphene oxide heated with GMR materials instead of the F-35's Have Glass V, which IIRC is carbon fibre wrapped iron oxides with nickel particles?
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How finely shaped the object that a ray of light is reflecting off of determines how the reflections look. If you’re trying to model that the two fundamental scalar parameters determining your model accuracy is the resolution of your model shape and the wavelength of the electromagnetic beam. If your shape resolution is not at minimum at the same scalar orders as the wavelength of your beam then you’re not modeling the actual reflections of the object you’re interest in to any level of meaningful accuracy. This is just basic physics. Beams that have cm wavelengths need shapes that have cm level resolution. And the amount of absolute difference in radiated quantities between 0.1 dbm and .001 dbm is *tiny*. So no, you cannot approximate with eyeballs.
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Same guys say B-2 RCS is lower than F-35 despite the larger size.
I'd wager radar emissions also contribute to RCS, especially if host and target are operating on the same frequency band.
As everyone else has pointed out, it's not really possible to say that any one fighter is better than another, especially if they're of similar quality to begin with. Still, there are some things that we have a fair level of certainty about. For starters, the F-22 and the J-20 are air superiority fighters whereas the F-35 is a multirole fighter. As such, you'd expect the former two to beat the F-35 in both dogfights and BVR combat. But because of their specialization, they are also far less good at strike missions. So what's better? It really depends on what the sides in question need and what else they have in their arsenals.
Another key factor that people tend to overlook is that the F-22 is old. Like really old. It was first made when the Pentium 4 was cutting edge technology and it has never seen any major upgrades since it came out. While it's still a very capable fighter plane, its avionics and electronics are very much outclassed now by new aircraft.
Finally, I like to think more in terms of what each of these planes can bring to a potential battlefield. And here, the only scenario that makes any sense is a conflict over Taiwan in the Western Pacific. And in this conflict, the F-22 is just about useless. It has short legs, it has no basing anywhere in the region, and as it's not carrier-capable, it has to be kept thousands of kilometers from the battlefield. It's just an impossible proposition. In contrast, the J-20 can be based only a couple hundred kilometers from the coast of Taiwan so they can be fielded in vast numbers. The USAF can't realistically deploy F-35As to the Western Pacific either, so the USN has to do all the heavy lifting but they will probably still be vastly outnumbered.
Another key factor that people tend to overlook is that the F-22 is old. Like really old. It was first made when the Pentium 4 was cutting edge technology and it has never seen any major upgrades since it came out. While it's still a very capable fighter plane, its avionics and electronics are very much outclassed now by new aircraft.
Finally, I like to think more in terms of what each of these planes can bring to a potential battlefield. And here, the only scenario that makes any sense is a conflict over Taiwan in the Western Pacific. And in this conflict, the F-22 is just about useless. It has short legs, it has no basing anywhere in the region, and as it's not carrier-capable, it has to be kept thousands of kilometers from the battlefield. It's just an impossible proposition. In contrast, the J-20 can be based only a couple hundred kilometers from the coast of Taiwan so they can be fielded in vast numbers. The USAF can't realistically deploy F-35As to the Western Pacific either, so the USN has to do all the heavy lifting but they will probably still be vastly outnumbered.
J-20/J-35 are in the same magnitude of RCS as F-35 and F-22. Whether one is better in certain angles/frequency doesn’t make too much difference in practical setting.
How big is the radar/EW upgrade between j-20 vs j-20A?