The RCS PAK-FA vs J-20?

[Corsair1963]

The majority seem to agree that the F-22 and F-35 likely have a much lower RCS than the PAK-FA. Which, got me wondering how the latter would compare to the J-20 or even J-31??? Any thoughts or opinions???

[lookieloo]

The Chinese have enough money to try a lot harder than the Russians. Other than that, no one here can really tell you anything.

[uclass]

The majority seem to agree that the F-22 and F-35 likely have a much lower RCS than the PAK-FA. Which, got me wondering how the latter would compare to the J-20 or even J-31??? Any thoughts or opinions???

Rear doesn't look particularly stealthy, no stealth nozzle design, nacelles don't look too stealthy and quad fins (see underneath) shouldn't help things.

Up front the canards are attached to the side of the intakes (as they must be with side intakes), this increases frontal cross-section. Fuselage below lip looks too rounded.

Very flat underneath wings, with rounded nodules at back, sure to be a favourite for radar return. I doubt much less than 0.01m^2 if at all unless they're using very special RAM.

[raptorzilla22]

I would say that the J-20 has a superior RCS, it has better planform alignment, canted weapons bays, DSI inlets, its overall frontal stealth appearance is very similar to the F-22 and F-35, but still its rear fuselage is "not that good", however I don't think that it will be competitive to the F-35/F-22 in terms of RCS and especially not if it comes to things like sensor stealth or IR signature reduction, but still its looks better than the PAK-FA, which in some ways has a really poor stealth design, like its non-hidden engine blades. I'm not sure how much the canards of the J-20 can sacrifice its stealth, but as long as they aren't moving a lot, there shouldn't be any bigger problems.

[milosh]

Shape isnt everthing. Lot depend on RAM. How good chinese RAM is? We really dont know. Chinese are new in that field.

Russians continue Soviet work on that subject. USSR even though didnt had stealth plane, did use RAM and did significant research in that field:
http://www.foia.cia.gov/sites/default/f ... 498135.pdf

[Corsair1963]

It's possible China could take want little export market that would be available for the PAK-FA. Honestly, besides say India and Vietnam. What other countries are likely to be interested in the PAK-FA???

[uclass]

Okay, just pointing something out which could make a difference:

http://www.janes.com/article/32190/pak- ... -published

"average figure of 0.1-1 m 2"

Does that mean an average with all angles taken into account, or is it a frequency average.

[KamenRiderBlade]

Okay, just pointing something out which could make a difference:

http://www.janes.com/article/32190/pak- ... -published

"average figure of 0.1-1 m 2"

Does that mean an average with all angles taken into account, or is it a frequency average.

The way I interpreted that figure is that is the Best to Worst end of the RCS depending on angle

[uclass]

Okay, just pointing something out which could make a difference:

http://www.janes.com/article/32190/pak- ... -published

"average figure of 0.1-1 m 2"

Does that mean an average with all angles taken into account, or is it a frequency average.

The way I interpreted that figure is that is the Best to Worst end of the RCS depending on angle

I too interpreted it that way but then I came across this:

http://paralay.net/pakfa/pakfa.html

Which gives the F-22 an average of 0.3-0.4m^2 looking at it from all angles. Am I not understanding something here, or is that horseshit?

[KamenRiderBlade]

You got to remember a few things when he makes a statement:

1) He supports his side, the Russian side, ergo he's going to trash talk the other side.
2) He's not privy to alot of secret US info
3) He may not be a true expert on RCS info unlike our Radar specialists on Stealth technology
4) Russia is behind the US on Stealth technology
5) Russia has a tendency to bluff alot of things, remember the many lessons from the Cold War (Remember all the ballon decoys they setup for our Spy satellites to photograph, remember all those propaganda parades that show off their vehicles)
6) The US has a tendency to understate things and list numbers that are far below what their real value is when it comes to our military capability, leaving some question as to it's true performance (e.g. the max speed of our Nimitz class carriers, the max depth and speeds of our Submarine, the actual RCS of the F-22 / F-35, the actual climb rate and ceilings of the F-22 / F-35)

So take what he says with a grain of salt.

[milosh]

My theory: He was talking about UHF.

[stobiewan]

Things have come on. When Lockmart started in stealth, they had to take a model out, stick it on a pole on a radar range and measure the entire thing at all angles. Now any random bloke can calculate all this stuff with SCIENCE..apparently.

[KamenRiderBlade]

Things have come on. When Lockmart started in stealth, they had to take a model out, stick it on a pole on a radar range and measure the entire thing at all angles. Now any random bloke can calculate all this stuff with SCIENCE..apparently.

Well the formulas for calculating stealth has been public knowledge for some time.

The Russian papers for doing that formula has been public knowledge.

As far as the techniques for reduction, that knowledge has been public as well.

So combine that with high quality computer models and math, you can make your own estimates if you so choose to do so.

[stobiewan]

You can make your own estimates if you wish but without the measurements of the actual object, they're likely to be adrift by several decimal places is my point. And no-one in the public domain has those numbers - that's my point. Someone looking at a few smudgy pics of an aircraft can't derive anything like a sensible figure for RCS.

You can look at some general forms of the aircraft and decide that as it's not got canted tail planes or that you can see the compressor blades, and come up with a best guess about the order of magnitude but when someone starts chucking around figures to two decimal places based on a press pack shot, I'm calling BS..