J-20... The New Generation Fighter II

Please, please don't go into rants like this. You show an utter lack of understanding of history and the term rule of law...and the workings of society in general. Just save yourself the trouble.

Asymptote said:

I think J-20 while a big step forward for China, will be nothing compare to the American F-22. There are many details, subsystems, that we don't know of that makes a huge difference when in combat. F-22 is design for all aspect stealth, while from the look of it, J-20 is only design for frontal stealth, with rear part of the design looking like a mess. So in a off chance that J-20 do face F-22 in combat, and assuming J-20's frontal stealth is as good as F-22's (doubtful) - the 2 planes will go into dogfight when they can't detect each other until its too late, and guess what, with rear stealth management a mess, J-20's ass is grass because it has little rear stealth compare to the F-22's, so it can't hide from it.

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About stealth, when the two are in dogfight, stealth is meaningless, because the pilots can clearly see each other, and they're so close that the heat signature is large enough to be targetted. Stealth from radar is usually most useful over long distances, cloaking the approach of the plane until it's too late. Bad rear-aspect stealth means land-based anti-air defences or aircraft can lock on to the J-20 more easily as it is leaving the target zone (i.e. after it has performed its mission). And the consensus seems to be that the tail is a work-in-progress. It would be premature to rate a prototype against an operational aircraft...we don't know half of what is in this plane.

Maggern said:

About stealth, when the two are in dogfight, stealth is meaningless, because the pilots can clearly see each other, and they're so close that the heat signature is large enough to be targetted. Stealth from radar is usually most useful over long distances, cloaking the approach of the plane until it's too late. Bad rear-aspect stealth means land-based anti-air defences or aircraft can lock on to the J-20 more easily as it is leaving the target zone (i.e. after it has performed its mission). And the consensus seems to be that the tail is a work-in-progress. It would be premature to rate a prototype against an operational aircraft...we don't know half of what is in this plane.

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Like I say in my last post (updated), "and with supercruise speed of Mach 1.82, there is little hope for J-20 to outrun F-22 in any type of scenario. That's not even factor in the superior training US pilots go through."


Also, let's assume the 2 planes are in dogfight, because F-22's box shape engine nozzles it will be shielded from both the front and sides, while the round shape J-20 engine nozzles is exposed and diffuse the heat and will light up at close range to the FLIR of F-22 even front on. Effectively, F-22 can fire at J-20 from any direction while J-20's only hope is to tail the F-22 from behind. And with inferior engines, lower super cruise speed (essential for dogfight), inferior combat training, it will be impossible for J-20 to even get behind F-22.

Let me just clarify, after thinking for a bit.
Basically, both PAK-FA and J-20's round shape engines, diffuse the heat and sticks out from the airframe body even front on. The FLIR would see the J-20's two heat signature "halos" from front on and more so from the sides. The F-22's box shape engine noozles are flushed against the airframe body, and cooled by layers of heat tiles until the tip of the noozles. So effectively, the airframe body shields the heat signature of F-22 from front and sides (the reason why F-22's engine noozles are recessed from the tail wings). So J-20 won't be able to detect F-22 front on (and sides) even with their FLIR turn on until its too late (long after American fire their missiles).


These are the little design details that makes all the difference in combat. It shows the thorough understanding and thinking process American has went through in their design as compare to Russian and Chinese.

Asymptote said:

Let me just clarify, after thinking for a bit.
Basically, both PAK-FA and J-20's round shape engines, diffuse the heat and sticks out from the airframe body even front on. The FLIR would see the J-20's two heat signature "halos" from front on and more so from the sides. The F-22's box shape engine noozles are flushed against the airframe body, and cooled by layers of heat tiles until the tip of the noozles. So effectively, the airframe body shields the heat signature of F-22 from front and sides (the reason why F-22's engine noozles are recessed from the tail wings). So J-20 won't be able to detect F-22 front on (and sides) even with their FLIR turn on until its too late (long after American fire their missiles).


These are the little design details that makes all the difference in combat. It shows the thorough understanding and thinking process American has went through in their design as compare to Russian and Chinese.

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What about the heat signature of the F-22 exhaust plume. It'll be detectable from the side and rear. The only way the F-22 can hide it, is from the front. There were report of heat resistant tiles/petal to be used on Chinese jet engine nozzle. I'm sure the same kind of heat resistant material can be used on the inner layer of the J-20 engine fairing.

Of course USA is just a country, but it is too rich for the rest of the world. They could develop anything they want and not worry about money. Although it looks like a financial downturn at the moment and budgets have to be cut back, it still gives me the impression of a rich man just lost a bit of money in his billion dollar stock, which he can't buy his billion dollar cruise now, but can only buy a Boeing 747 instead.
America is probably the only superpower in history that constantly goes to war but remains unharmed from it. This gives it tremendous amount of experience and also create demand for innovation. When coupled with their vast resources, they could come up with a lot of things that other countries might not even know that could exist.
I do agree with the idea that J-20 is not 100% on par with F-22, mostly because of the fact that China does not have real wartime experiences compared to the Americans, and especially that it did not go through the arms with with the Soviet like the Americans did. Because of this, the J-20 might not be as well rounded as the F22.
This is does not mean that the Chinese engineers are not as smart as the American counterparts, it's just that they don't have as much experience. This is just like a city boy vs. a country boy. A country boy that's always in the wild will know what to bring for camping and what not to bring. The city boy, who had always lived in the metropolis, probably wouldn't even know what to bring. He would probably bring a lot of useless things and miss the things that's actually important.
This is why I always think that China needs to go through small war with some small countries. Without an actual war, you can never find out what is really important and what is not.
Another thing I have notice about the Chinese arms industry is that they do not do as much of groundwork as the Americans do; not sure if this is lack of fund or what, but there seem to be a lot of bottlenecks whenever something is being developed. On the other hand, a lot of things the Americans develop almost always have technologies that seem to already matured for it.

Quickie said:

What about the heat signature of the F-22 exhaust plume. It'll be detectable from the side and rear. The only way the F-22 can hide it, is from the front. There were report of heat resistant tiles/petal to be used on Chinese jet engine nozzle. I'm sure the same kind of heat resistant material can be used on the inner layer of the J-20 engine fairing.

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I think to a lesser extent from the sides because the F-22 engine nozzles are recessed and shielded by the rear wings. Actually, taking another look at the J-20, it seems J-20 did design it similarly as well, recessing the engine nozzles so its shielded from the sides.

So you can only approach the F-22 from the back, where the heat signature is unshielded.

Also, I think the shaping of the nozzles plays a big part. Round noozles diffuse the heat so a "halo" effect will appear front on. The rectangular box shape nozzles that's flushed against the airframe will be cooled by the airframe's jetstream because it's flushed against it.

So it doesn't matter if CAC used heat tiles on the engine nozzles, if the shaping is wrong no matter how much heat tiles you apply it will still be ineffective. Its like the stealth fighter design, shaping is probably 80% of the stealth, with the rest absorb by the RAM coating.

Asymptote said:

I think to a lesser extent from the sides because the F-22 engine nozzles are recessed and shielded by the rear wings. Actually, taking another look at the J-20, it seems J-20 did design it similarly as well, recessing the engine nozzles so its shielded from the sides.

So you can only approach the F-22 from the back, where the heat signature is unshielded.

Also, I think the shaping of the nozzles plays a big part. Round noozles diffuse the heat so a "halo" effect will appear front on. The rectangular box shape nozzles that's flushed against the airframe will be cooled by the airframe's jetstream because it's flushed against it.

So it doesn't matter if CAC used heat tiles on the engine nozzles, if the shaping is wrong no matter how much heat tiles you apply it will still be ineffective. Its like the stealth fighter design, shaping is probably 80% of the stealth, with the rest absorb by the RAM coating.

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I'm not sure what you mean by the halo effect. The heat signature comes from the surface of the aircraft itself. A well insulated surface will be red hot inside and cool enough on the surface. That's how the heat signature is reduced if the engine is well covered with a thick layer of heat resistant material, like that of the F-22. J-20, otoh, seem to be better covered on the underside than on the topside.

to asymptote:

Supercruise has nothing to do with dog fight mate, because one does not "cruise" during dog fight & going too fast will simply lose your target. It's all up to aerodynamic agility, aam as well as pilots' ability to lock on & fire fast. Stealth is completely useless during dog fights, which is within visual range in case you don't know, considering the sensitivity of modern ir seekers. With the same weapon & electronic suite F-22 would hardly fare better against F-15 etc.

The plane we call J20 is no more than a techno. demonstrator or early prototype, the same as YF-22 over 20 years ago. The only thing we know for sure is the final product will not be what we witness today. Without knowing the engine, sensor or weapons on board J20, your argument hasn't got a leg to stand on.

By the way a weapon is designed with specific purposes on designers' minds. J20's lack of all-direction stealthy capability may suggest they don't intend to use it for penetrative missions at all. So is Russia's PAK FA (they are more like defensive weapons comparing with F-22, are they designed to neutralize threats from F-22 in the first place?). To evaluate fighters without referring to their specific mission environments is awfully silly I reckon.

EDIATH said:

to asymptote:

Supercruise has nothing to do with dog fight mate, because one does not "cruise" during dog fight & going too fast will simply lose your target. It's all up to aerodynamic agility, aam as well as pilots' ability to lock on & fire fast. Stealth is completely useless during dog fights, which is within visual range in case you don't know, considering the sensitivity of modern ir seekers. With the same weapon & electronic suite F-22 would hardly fare better against F-15 etc.

The plane we call J20 is no more than a techno. demonstrator or early prototype, the same as YF-22 over 20 years ago. The only thing we know for sure is the final product will not be what we witness today. Without knowing the engine, sensor or weapons on board J20, your argument hasn't got a leg to stand on.

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It is not a tech demonstrator, that is proven through and through. The J-20 is a prototype.

The YF-22 tech demonstrator flew in 1990. That is not the J-20 equivalent. Rather, the J-20 is comparable to the first F-22 prototype which flew in 1997.

The YF-22 demonstrator was only built because the US government couldn't decide which design to go with (the F-23 or F-22).

The J-20 is the final design, it is already chosen, there is no competitor. It is a prototype.