Originally posted by HatTrick
BTW - round exhaust nozzles = stealth FAIL
However, it's a very cool looking rendering.

Not necessarily.

With the correct bodywork around the nozzle, you can restrict the avenues* for incoming waves to generate reflections back towards the source without using a 2D nozzle.


*to azimuthal angles that are usually not important.

I saw one that looked similar but had rows of the red things on the back and hoovered as well as was stealth. Saw it several times right over my house... I did not see any of the wings on the top as it slowly crused away.

At least the rendering and the real aircraft have some similarities. For one, neither exist in the real world. I look forward to the day it flies, however.

[edit on 31/7/2009 by C0bzz]

The round exhaust nozzles would certainly hurt stealth and increase infra-red signature , would be an obsolete application for thrust vectoring as well. . The top air intake is rather unpractical if it is duplicated at the undernetah wing space. Yet it looks great. Check out the next generation attack helicopter in my photos in my profile. leave comments

Originally posted by Advancedboy
The round exhaust nozzles would certainly hurt stealth and increase infra-red signature , would be an obsolete application for thrust vectoring as well.

Pretty much no, no and no on those three points.


Round exhaust is more efficient for thrust and more efficient for TVC as a result.


A fixed diffusive nozzle, more like the B-2 or F-117 is better for IR, but useless for variable area or for thrust vectoring.


The round nozzle may, on first glance, not be great for all aspect radar signatures, but as I said, absorbing or reflective shrouds can conceal the nozzle to a large extent and restrict significant returns to unimportant azimuthal angles.

Originally posted by kilcoo316
A fixed diffusive nozzle, more like the B-2 or F-117 is better for IR, but useless for variable area or for thrust vectoring.

Clarification: Useless for 3D TVC as implemented on other modern Russian aircraft. F-22's non-circular intakes allow for 2D TVC, but the Russians are quite big on full 3D, so it's likely that they will stick with it on PAK-FA.

Originally posted by Darkpr0
Clarification: Useless for 3D TVC as implemented on other modern Russian aircraft. F-22's non-circular intakes allow for 2D TVC, but the Russians are quite big on full 3D, so it's likely that they will stick with it on PAK-FA.

No, The F-22's nozzles are not the same as the B-2 or F-117.


Those are fixed diffusive nozzles which actively try to mix ambient with jet air to reduce IR signature.


The F-22 has a variable area nozzle, and while it may be rectangular, it does not try to reduce IR signature. But of course, it can be used with thrust vectoring.

Originally posted by deltaboyConcept pics of the PAK. Could be a fake I think.

They are.

I look at the wiki and it mentions that it would be stealthy.

Thats the reason why Russia is even bothering with making the PAK FA in the first place lol. Otherwise they would continue the flanker series with new variations like for example: SU-37BM (Made up plane by me!)

if you design a plane based on stealth then it would have to look something like in the pics or the F-22 or the F-35, can't be with curves and so on. So you think a Russian plane with stealth be looking something like this even if this concept is not real?

Concept isnt real and it wont be build in a form like this one. It just misses IRST sensor for example which is vital if your advesary is equaly stealthed and you cant detect him with your radar. Also it doesnt look like it has feathered nossels which is stealth fail.

Originally posted by IAF101Very Majestic looking aircraft but I doubt the finished product would look anything like that. They are promising a LOT from super cruise to stealth but I fear they wont be able to deliver quite as well on all their promises.

We will wait and see.

The AESA radar itself is going to be a monumental challenge for them. Not to mention decent engines.

AESA radar for the PAK FA is already more or less finished and shown on MAKS 2009. Engine work is in full gear. But yeah, it is quite a big task at hand.

Its shocking that the Russians despite being the originators in the study of
"Stealth" have not bothered to replicate the American successes in the same field.

not in the field of radar stealth but on other stealth area's like IR and visual stealth, Russians are on par with IR at the very least and are dramaticaly more superiour in the area of visual stealth by applying camouflage on the planes.

Originally posted by paraphi do wonder whether Russia can afford to develop aircraft as being proposed - after all, their GDP is not that big.

Russia's GDP might not be that large, it has however the advantage that stuff in Russia is in general much more cheaper in then western countries and wages are also a bit lower. Coupled by the fact that it can cut some corners by using MFI and SU-47 as early testbeds and possibly the fact that it might resemble a stealthyfied SU-27.

The Europeans long ago pooled their developent resouces (with the exception of France, of course)

That i think has to do with the fact that European country's in general have a low defence budget and that wages and stuff like that is much more expensive then in Russia for example.

and the US are curtailing F22, probably because they don't actually need such a plane and it is rather costly.

Well, even if it isnt neccesary it will provide Russia with important knowledge about Radar stealth and can apply that to future UCAV systems and to the PAK DA.