Chengdu J-20 5th Generation Aircraft News & Discussions

[帅的一匹]

just bring F-22 on the table

---------- Post added at 12:59 PM ---------- Previous post was at 12:58 PM ----------

Japan is very clever when they make decision in military procurement.

 

[帅的一匹]

Thats because F-22 is not available for export, so Japan went for second best. Besides Japan can use F-35's on its helicopter carriers(with some modifications).

You are right man! The truth is F-35 is not the best in stealthy design, it accomadate too many using request of investment sides, this make it no special. I think SU-35 is even better, Indians should go for that.

 

[Obambam]

The Japanese did ask for the F-22. The Americans refused. The F-22 is strictly not for export after Congress voted for a ban on exports.

The Japanese military think tanks cost/benefit analysis tells them F-22 is the one to go for.

However, the American military think tanks cost/benefit analysis tells them otherwise. Hence the F-35 was offered instead and will be the one they will get at best.

 

[Broccoli]

USA would never sell a plane (even for friendly country) what could give really hard time for USAF in case of war.

That is the reason why they refuse to sell F-22.

 

[Zabaniyah]

You are right man! The truth is F-35 is not the best in stealthy design, it accomadate too many using request of investment sides, this make it no special. I think SU-35 is even better, Indians should go for that.

The F-35 is still a 5th generation plane, a generation ahead of the SU-35. It has the most advanced avionics, even more so than the current F-22s. But inferior in terms of stealth.

 

[帅的一匹]

The F-35 is still a 5th generation plane, a generation ahead of the SU-35. It has the most advanced avionics, even more so than the current F-22s. But inferior in terms of stealth.

S-35 is not that as advanced as F-35, but it's lot more radius, cheap and affordable.

---------- Post added at 01:18 PM ---------- Previous post was at 01:16 PM ----------

I would rather have 1000 J-10b not 200 F-22 in hands.Volume is important in war.

---------- Post added at 01:19 PM ---------- Previous post was at 01:18 PM ----------

especially for those country not kind rich debt as uncle Sam.

 

[Zabaniyah]

^Compared to other 4.5G planes, the SU-35 doesn't come cheap my friend.

The F-22 is a class of its own.

 

[gambit]

"Lumps and bumps" seriously degrade F-35 stealthiness

The original X-35 was a stealthy design. The current F-35 SDD AA-1 is a "much inferior contoured design, clearly intended to accommodate the larger weapon bays."

And challenged, if not outright debunked, here...

http://www.defence.pk/forums/china-...craft-updates-discussions-21.html#post1929505
http://www.defence.pk/forums/china-...craft-updates-discussions-23.html#post1934472
http://www.defence.pk/forums/china-...craft-updates-discussions-24.html#post1937502
http://www.defence.pk/forums/china-...craft-updates-discussions-26.html#post1942400
http://www.defence.pk/forums/china-...craft-updates-discussions-27.html#post1945087

 

[DrSomnath999]

it should also be noted that a flat plate focuses its backscattering
on a very narrow angular sector, with a high RCS value.
A sphere, by contrast, has a low RCS value which is uniform at all angles.
Thus, on a limited angular sector around the specular direction, spheres
and cylinders give the lowest RCS values. If otherwise, RCS must be kept
low on a wide angular sector, then it is better to use very narrow-beam
shapes such as the flat plate, correctly aimed in order to avoid the specular
flash [7].

are single piece canopies more stealth than two pieces if so what about F-35, B-2 or F-117?

Square trihedral corner reflector Strongest radar return due to triple reflection of incident wave



Right dihedral corner reflector Second strongest radar return due to double reflection of incident wave; decreases from maximum slowly with changing θ and rapidly with changing φ


Flat plate Third strongest radar return due to direct reflection of incident wave; decreases rapidly as incidence angle changes from perpendicular



Right circular cylinder Strong radar return as aspect (&#952 changes, but decreases rapidly as azimuth (&#966 changes

 

[gambit]

It's simple physics to understand the reason that a cylinder is not stealthy. An incoming radar beam impacts the side of a cylinder. The entire length of the cylinder reflects the radar signal. This is obvious and Gambit has lost his mind in claiming otherwise.

Here's a question though: you're using the ray model (with the implicit assumption that the cylinder is very large compared to wavelengths; good in optics, bad in radar). what about diffraction effects of the cylinder? what if the cylinder is conducting?

however, I do remember a physical optics model that takes into account diffraction and interference in Air Power Australia that gave J-20 all directional stealth in 9 wavebands.

I've been typing for hours in having to deal with those two guys, who were clearly wrong. I'm sorry, but I'm done for tonight. My eyes hurt.

However, let me say that I've never heard of a cylinder conducting all of the incoming radar energy in the real world. You might be able to build a small laboratory prototype under specialized conditions. However, I'll like to see them build a fully-conducting flying airframe. It's b.s.

Also, why bother stopping at a cylinder? Why not make the whole plane conducting and not worry about stealth shaping at all?

I would put an entirely radar-conducting surface/airframe into the same b.s. heap as plasma stealth and Russian radar blockers. What a bunch of hooey. They never have a reputable citation and keep throwing crazy ideas out there.

The BOTH of you have a false understanding of the word 'conducting' in this context. As English is not my first language, am going to be kind to both of you for this.

Get this straight: EVERYTHING IS A CONDUCTOR. We will confine this to EM signals for now but the idea is applicable to sound as well.

Whenever an EM signal impact a body, the body's surface is a 'conducting' pathway or 'electrical path'. It does not matter if the body is the simple sphere, a plate, a cylinder, or as complex as an aircraft.

EVERY BODY is effectively a 'conductor'.

EVERY STRUCTURE on said body that made up said complex body is a 'conductor'.

A golf ball is not a simple sphere. All those 'dimples' turned it into a complex body and every dimple is a 'conductor' in both electrical paths and in diffraction behaviors.

Now comes the cylinder...

It's simple physics to understand the reason that a cylinder is not stealthy. An incoming radar beam impacts the side of a cylinder. The entire length of the cylinder reflects the radar signal. This is obvious and Gambit has lost his mind in claiming otherwise.

This is stupid. I have explained many times here on what is called the '10-lambda' rule when it comes to spheres, cylinders, and effectively curvatures. Of all who are interested in more technical details, looks like YOU are the only person who is ignorant of it.

The most recent of that explanation is here => http://www.defence.pk/forums/milita...-ratios-all-fighter-planes-5.html#post2473648

When it comes to curvatures, either on a sphere, a cylinder, or just an arc that is part of a structure, the '10-lambda' rule comes into effect -- IMMEDIATELY. The issue is NOT the structure itself, which is the cylinder, but rather the wavelength (lambda) to radius (or diameter) of the conducting path. In essence, the '10-lambda' rule said: For that curved electrical path, be it on a sphere or a cylinder or as an arc on a structure, if that path is greater than 10 wavelengths (lambda) of travel, the creeping wave effect WILL NOT occur.

This is what/how a 'creeping wave' effect is visualized...

A rod is a cylinder. A rod is called that because of its visual effect as a cylinder is not as pronounced. But structurally speaking, a rod is very much a cylinder.

For the illustration above...

The first example is what happens IF the diameter is greater than 10 wavelengths. The 'creeping wave' effect will just simply radiate itself into free space and very much away from source source direction, giving the detector only that tiny amount of initial specular reflection. Even on a curve, there is always a tiny amount of real estate that is flat enough and perpendicular to the impinging signal. Hence, even on a curve, there is always a tiny amount of specular reflection.

The second example is when the diameter is less than 10 wavelengths (lambda). The detector will receive the initial specular reflection. But now there is a creeping wave effect to add to that tiny amount of specular reflection.

So when measuring a cylinder ONLY from its ends, that is being deceitful to the readers. Even the simple sphere deserves more than one measurement methods: One to measure that initial specular reflection, then another to measure its diameter regarding surface behavior on the 'shadow' region. That is why posts 1208 and 1209 cannot be taken seriously regarding any objective criticisms for the F-35.

The '10-lambda' rule and its parent, the wavelength to diameter ratio (or relationship), are well known as in DECADES of radar experience over many countries.

Note the significant: As a result, quantitative analyses, for spheres as large as 10λ in radius, of arbitrary materials, even in contact become feasible.

Ten wavelengths λ in radius.

Equally significant is the phrase 'of arbitrary materials' because it means different materials have been tested and found to be CONDUCTING materials.

But there are more...

Note the wavelength to diameter relationship in the first paragraph: 'The creeping wave is the largest single contributor to backscatter near nose-on for cone-spheres with sphere radius-to-wavelength (a/&#955 ratios less than about 3 and for cone half-angles less than about 20°.

This wavelength to diameter relationship is once again significant but this time instead of being 10 wavelengths we have less. This is because we are dealing with cone-spheres what complex body has a 'cone-sphere' like structure? A missile. This paragraph is talking about using the wavelength to diameter relationship in trying to detect missiles.

Finally...

Once again, the '10-lambda' rule or wavelength to diameter (a/&#955 relationship is used by other people in their research. But note the authors' names and guess their national origin.

So now we have at least three examples of how, when it comes to curvatures on any complex body, specular reflections becomes less significant compared to surface wave behaviors. The APA so-called 'analysis' using Physical Optics ALONE does not take into consideration these surface wave behaviors. What APA did was effectively hand-waved away such trivialities out of their hostility to the F-35.

And a certain Chinese member here is telling the readers that I have no support for my arguments...???

 

[SQ8]

]What APA did was effectively hand-waved away such trivialities out of their hostility to the F-35.
[/B]

And a lot more..
It is Extremely biased in exaggeration of eastern equipment capabilities for THIS very reason and therefore unreliable.

 

[gambit]

I like that. I suck at Photochopping stuff but saved a copy of it.

 

[Peaceful Civilian]

USA would never sell a plane (even for friendly country) what could give really hard time for USAF in case of war.

That is the reason why they refuse to sell F-22.

This clearly shows that F35 is degrade version of F22. Less technology, Less stealthier than the original F22. Only speed is Mach 1.6+.
USA is very clever. They have less budget for more F22, That's why USA offered F35 and opened it for export to help same money For F22.

 

[gambit]

This clearly shows that F35 is degrade version of F22. Less technology, Less stealthier than the original F22. Only speed is Mach 1.6+.
USA is very clever. They have less budget for more F22, That's why USA offered F35 and opened it for export to help same money For F22.

Please...Stop...The F-35 is not any type of 'degradation' of the F-22. The F-35 is a totally different aircraft for a different mission type. Why not say the F-35 is a 'degraded' version of the B-2 since both aircrafts drop bombs?

 

[DrSomnath999]

I like that. I suck at Photochopping stuff but saved a copy of it.

Sir ,i have not been promoted to researcher in my forum just for granted .