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The canards on an aircraft diffract the radar waves backwards in an expanding cone shape (knife edge effect). The diffracted electromagnetic waves do not radiate in front of the aircraft, but towards the back. Think if it like putting a rock in a stream. The ripples don't propagate in front of the rock, but outwards and away behind it. You wouldn't feel the ripples if you put your finger in front of the rock. It's the same thing with the J-20. The waves are not propagating towards the front, but towards the rear. As the J-20 is a mainly strike fighter, that is okay because it's the front that will be
exposed to enemy radar.



When edge diffraction occures off of a canard the EM energy does indeed still have the potential of comming back to the receiver, infact it usually does, dispite not being directly in the line of sight of the aircraft's frontal hemesphere. When edge diffraction (from a canard) occures one of the first parts of an aircraft that make impact with the EM signal is the leading edge of the main wing, the entire leading edge is curved or shpereical--recall how most Chinese members like to take cheap shot at the pak-fa and it's IRST housing? Well the leading edge of a wing is spherical just like an IRST housing, except that the area of a leading edge is hundreds or thousands of times the size or area of a IRST sphere.

Example of a leading edge:




Recal how a sphere is able to dissipate most of its energy? For instance a 6" has a rcs of 0.018 M2, that RCS is from the very front of the sphere because all other angles of the sphere cause EM to scatter in all directions.

Example:



Simply put, the leading edge of a wing is like hundreds or thousands of spheres--same frontal geometry but amplified many times over.

You may be asking why this doesn't apply to other aircraft, and the answer to that question is that a conventional, none canards, aircraft will not have edge diffraction occuring in front of its leading edges. Than the question will be why doesn't EM energy simply bounce back off the leading edge of any 'stealth' aircrat's wing? The answer to that question is because the beam width may spread out to where the beam acts like a radars side lobes, meaning the energy is generated outwards and not head on. What edge difraction does is that it gathers EM energy from a wings surface and it directs it off of one point, so when edge diffraction occures off a canard it directly makes impact with the leading edge, and remember the leading edge comprizes a large area.

Further, the J-20's wings are very conventional unlike other stealth aircraft, conventional wings often cause edge difraction to actually come back to the receiver, in other words the scattering can be directed towards to receiver. Lets take the B-2 for example, the B-2 has a very complex and unique wing geometry with the 'sawtooth' patterns, they did not incorporate these 'sawtooth' paterns for fun or because it looked cool, they did this to minimize the chances of EM signals heading back to the receiver, in other words they wanted the EM signal to disspersse behind the wing and not in front.

An example:







Even if the canards do cause some problems, it is compensated by the fact that the J-20 does not require for horizontal stabilizers (unlike F-22, T-50, and F-35). The canards also add much more maneuverability.




This statement just proves that you do know know anything about edge diffraction or radar theory or an aircraft's design and how EM signals interact with it.


The "complex" fuselage of the T-50 ensures nothing but a greater chance of an increased underside RCS. The intake ridges will severely cause radar diffraction and so will the gaps between the intakes and the centroplane. The T-50 takes its airframe from the Flanker family, and frankly, that's about the worst decision you could make if you take RCS as a priority.


The fusalage/intakes are angled, and based off of the design i find it impossible or extremely unlikely that an EM signal will bounce off of the intake, collide with the 'centroplane' and make it back to the receiver when none of those areas are aligned to cause the EM wave to return to its original source, in other words, once the EM signal hits the inside of the intake, it will than bounce and hit the 'centroplane', after it hits the 'centroplane' it is directed downwards. How you came to the conclusion that 'radar diffraction' will occure is beyond me. I suppose when one disregards the laws of physics anything is possible.






Canopies have to be made out of a material that allows electromagnetic waves to pass through it unhampered. This means that no metal can be present anywhere on the canopy. That's why aircraft like the F-22, J-20, and F-35 all have sloped single-piece canopies. As soon as metal is present, that translates to a few more digits that you are going to have to add to your RCS number. T-50 uses a sliding canopy that has to rely on metal, which will undoubtly increase its RCS.



This is fanboy nonsense that you are making up. Firstly, treated canopies are designed so that no EM energy enters the cockpit because once it does the EM will scatter everywhere and return to the main source. Also your assertion that no metal can be present is rediculous, as stated before the B-2, F-117 and many other aircraft had 'metal' frames.

The frames, first of all, may not even be metal, secondly even if they would be they would be sprayed with RAM, as opposed to being exposed metal, lastely, the canopy and the frame are the same in geometry, meaning the frame follows to contour of the canopy; if the canopy is slopped at 30 degrees, so is the frame. By your logic since the F-22 or J-20 also have metal they too should have increased RCS.


Speaking of the J-20's wing geometry, the surface is very smooth and consistent, while the T-50 and F-35 have constant bumps and flaps.



Than what do you call those four cylindrical 'bumps' under the wings?



The T-50, F-22, and F-35 also have horizontal stabilizers that will light up an enemy's radar like a Christmas tree from the rear.

Thank you for contradicting yourself, so rear horizontal stabalizers will cause an enemy's radar to light up like a Christmas tree but the J-20's canards do nothing. Intersting how the laws of physics don't apply to the J-20. And unlike the J-20 the rear stabilizers of the F-22 and pak-fa blend into the main wing, they do not just stop like a canard.
 
Do a little research before you spaut nonsense, Russia still has the highest trust rocket engine ever produced as well as a two decade old craft that surpasses any modern day Chinese rocket in LEO capacity.

Seriously Mr. PT, you and I are not experts in stealth. There is more to it than your simple explanations. However, Russian T-50 is really a disappointing plane. I am a Russian military fan btw. I loved the SU-30s....

Only an Indian would buy that crap now.... hopefully Russia still has some 'real' research going on instead of the T.50. The quality of the planes looks worse than a FC-1.
 
The Russian arms industry has one of the highest export vs investment rate in the world. This is not due to the performance of Russian weapons but their miniscule investment. This has already translated into Russia falling into the same generation of fighters as China...?

Russia is living off of the legacy of the Soviet Union. But then again, we love to export our resources for American toilet paper too. What's wrong with the Russians selling their blood for European a s s wipers?
 
Seriously Mr. PT, you and I are not experts in stealth. There is more to it than your simple explanations. However, Russian T-50 is really a disappointing plane. I am a Russian military fan btw. I loved the SU-30s....

Only an Indian would buy that crap now.... hopefully Russia still has some 'real' research going on instead of the T.50. The quality of the planes looks worse than a FC-1.

did you personally inspect T-50 fighter ?? or you are a super expert who can tell the quality of the fighter plane just by looking at the youtube videos??
Do you think a country which is investing $ 25 B in this project want to buy craps??:lol:
 

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