You've forgotten the RCS spikes from directions perpendicular to the leading and trailing wing edges and perpendicular to the nose, airframe, and canted vertical stabilizer.
J-20 5th Gen Fighter Thread V
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Equation
Lieutenant General
So...in other words only the F-22 are allowed to have RCS spiking (input excuse here_____) and the J-20 doesn't (input assumption to be confused as facts here_____)?
Carlos Kopp's RCS study was also only about trying to find flaws within the basic aircraft design of the various 5th gen aircraft. It doesn't consider ram coating for example.
And his result was that the basic design (I think it was even the first design without the later improvements) was a solid stealth design.
And his result was that the basic design (I think it was even the first design without the later improvements) was a solid stealth design.
The point is that the F-22's RCS spikes are effectively unexploitable. The J-20's, aren't, and mean it must always be wary of emitters and align itself to avoid detection. Basically, the J-20 has an x-shape in the frontal 90 degrees of its polar graph, from which if you scan it, it lights up. The J-20, then, must always try to avoid exposing its hot-spots to its opponents. It's not a fatal weakness, but it's a real one.
Very narrow windows where RCS spikes may not matter much in practice. Spikes that appear and vanish almost instantly aren't exactly usable detection and tracking. You'd have to align your sensor to the specific area of the spike to detect it. Furthermore, those spikes may not exist in the actual aircraft, given different RCS reduction treatments.
Really don't understand how you could say "both sides misunderstanding canards" after thousands of scientists and engineers from both China and US have done research works in decades in this area. For the US part, besides X-36, I can easily point out another three samples.
Here
and here
and even on a F-4
The bottom line is one does not need to build inducted aircraft in order to fully grasp the characteristics of canard. That is the job of theoretical scientists, their wind tunnels and super computers. They make full-sized demonstrators above to verify everything they need. If you rely on inducted (operational in numbers) to decide on something, it is too late, and surely a very bad homework.
In the US defense community, the cliche is that the best place for canards is on the other guy's plane. That is to say, since there's a traditional aversion against canards, despite its maneuverability benefits, it requires justification.
As far as both sides misunderstanding the matter; I'm talking more about the analyst community than the research community. The US community hates canards, even though the Lavi was enough of a threat to the F-16 that the US moved to get it cancelled. The Chinese side tends to be overly optimistic about the stealth penalties of canards.
@latenlazy: The problem is more that if the J-20 is picked up by a AEW&C at long range (as will happen), it can vector fighters to exploit the RCS spikes. It constantly knows where the J-20 is, but the fighters' sensors don't, and more importantly, neither do their missiles.
As far as both sides misunderstanding the matter; I'm talking more about the analyst community than the research community. The US community hates canards, even though the Lavi was enough of a threat to the F-16 that the US moved to get it cancelled. The Chinese side tends to be overly optimistic about the stealth penalties of canards.
@latenlazy: The problem is more that if the J-20 is picked up by a AEW&C at long range (as will happen), it can vector fighters to exploit the RCS spikes. It constantly knows where the J-20 is, but the fighters' sensors don't, and more importantly, neither do their missiles.
kwaigonegin
Colonel
you do have a point but so does taxiya. The US understand canards as well as anyone else in the world. The knowledgebase about anything flight related stands above everyone else.
With that being said you are absolutely right in that we don't necessarily always field the best that we can because of community/political influence and the MIC and lobbyists.
The US are just not big fans or canards just like we're not big fans of delta wings anymore. The F-16XL was phenomenal and so was the forward swept wing designs. Initial NASA/USAF studies etc yielded amazing results but despite them, these planes remained as prototypes only. They got killed off before more research dollars and testing were poured into them.
The same can be said in the automotive world though. Prototype cars are eons more advanced and capable then what we see on mass produce cars.
With that being said you are absolutely right in that we don't necessarily always field the best that we can because of community/political influence and the MIC and lobbyists.
The US are just not big fans or canards just like we're not big fans of delta wings anymore. The F-16XL was phenomenal and so was the forward swept wing designs. Initial NASA/USAF studies etc yielded amazing results but despite them, these planes remained as prototypes only. They got killed off before more research dollars and testing were poured into them.
The same can be said in the automotive world though. Prototype cars are eons more advanced and capable then what we see on mass produce cars.
"spikes".
It gets a little tiresome. If canards are such a design flaw for stealth designs we wouldn't see them on any design study for stealth designs if we now at the point where the J-20 can be detected and tracked on long ranges.
The Euroncanards have all way better RCS stats than American 4gen aircraft although not deploying strict stealth design design rules.
Kopp's study gets referred like it's the last word and even Kopp called the J-20 well designed in that regard.
It gets a little tiresome. If canards are such a design flaw for stealth designs we wouldn't see them on any design study for stealth designs if we now at the point where the J-20 can be detected and tracked on long ranges.
The Euroncanards have all way better RCS stats than American 4gen aircraft although not deploying strict stealth design design rules.
Kopp's study gets referred like it's the last word and even Kopp called the J-20 well designed in that regard.
The J-20 has been designed to meet the very high portal set by the F-22?? Canards were deemed advantageous for the J-20 in order to give her rapid "pitch transitions" in instead of turning to OVT!
Every Fighter Aircraft, EVERY Fighter Aircraft, is a collection of strengths, and liabilities?? even when you decide how much internal fuel you need?? to how many hardpoints will you plumb for fuel?? that is just one very important area, out of probably at least 100 to 200 design parameters for an aggressive, competive fighter!
While it is important for our purposes to examine the J-20 and her fellows very carefully, and its fine to imagine?? prognosticate on an intellectual level, it would be far more intelligent to advance your ideas in the best possible light, and allow the "truth patrol" to tell you how well you have done?
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