Russian Su-57 Aircraft Thread (PAK-FA and IAF FGFA)

Air Force Brat

Brigadier
Super Moderator
Read the man's post again. Okay so Su-57 is not stealthy in the league of the others. Therefore it must have something better up its sleeves? What kind of reasoning is this? That simple. Rest is off topic. Leave J-20 out.

in your own words the SU-57 is NOT as stealthy? that's the main parameter for being a 5 gen aircraft, reduced RCS,,, the other 5 Gens do appear more stealthy, and do require a Luneburg lense to operate in traffic..
 

ougoah

Brigadier
Registered Member
Yes it doesn't seem as stealthy as the others (not including current prototype FC-31s which are also not stealthy). As far as we know, it wasn't wearing what we consider the usual luneburg lense into Syria. However no information at all can be extrapolated from these facts (assuming we are correct in the observation of LL presence). Whether J-20 has some ECM similar to the function of SPECTRA, is so far from this line of discussion.
 

Lethe

Captain
Su-57 has the shaping and elements of stealth fighters ie internal bays, passive sensors, LPI AESA radar(s). It is obvious enough to the naked eye that it is not a stealthy fighter though.

No, it is not obvious to the naked eye. There are reasons to suspect that Su-57 might not enjoy the same level of signature reduction as F-22, but this does not translate to the claim that it is not "stealthy", let alone that it is an inferior combat system in its intended operational context.

RCS signatures are a series of continuums. On the one end of the scale there are platforms that employ no signature reduction measures, such as the F-15 or B-52, then there are those that employ modest signature reduction measures like Super Hornet, B-1B and the Eurocanards, and at the other extreme we have tailless platforms like the B-2. So-called "fifth generation fighters" all have higher RCS than the B-2 owing to their basic layout, yet we still call these aircraft "stealth aircraft". That Su-57 has a greater radar signature than other fifth-generation fighters tells us basically nothing about where it lies on this spectrum, let alone the operational implications in various dynamic contexts.

One thing we can be sure of, however, is that the designers of Su-57 are far more aware of the factors influencing RCS than lay observers are, and that the choices made are the product of careful judgments made according to specific operational requirements, cost/maintainability factors, and general design philosophies. As a general rule I don't second-guess the engineers of any nation. It is safe to assume that they know what they are doing. The question worth considering is, are they pursuing the right end? And I don't think there's enough information available to answer that.

Most of the more strident criticisms of Su-57 boil down to the simple logic that it is different to what the Americans have done and therefore it is wrong -- only with the novel twist that China is jumping on the bandwagon too. This is a nationalist and myopic perspective that will lead one astray as often as not, as it has on many previous occasions. None of this stuff has been validated in a peer threat environment, and until it has one should remain cautious about drawing conclusions that exceed the available data.

I don't have time for American or Russian posters who reflexively dismiss Chinese achievements, nor do I have time for Chinese posters who dismiss Russian achievements.
 
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ougoah

Brigadier
Registered Member
No, it is not obvious to the naked eye. There are reasons to suspect that Su-57 might not enjoy the same level of signature reduction as F-22, but this does not translate to the claim that it is not "stealthy", let alone that it is an inferior combat system in its intended operational context.

When I said obvious to the naked eye, I was referring to how easy it is for casual observers to see that the plane indeed has vents under its belly, protrusions of all sorts of stuff everywhere, two piece canopy, uneven surfaces on panels. More careful attention is paid on US stealth aircrafts to avoid all of these things. Unless these things don't matter to the RCS of a plane, it is therefore obvious to the naked eye that the Su-57 is not a stealthy fighter in the same regard as the LockMart products. I never suggested it is an inferior combat system in fact I made it a point to include that it may very well be a more effective fighter for its role in the RuAF than its peers in the USAF and elsewhere.

RCS signatures are a series of continuums. On the one end of the scale there are platforms that employ no signature reduction measures, such as the F-15 or B-52, then there are those that employ modest signature reduction measures like Super Hornet, B-1B and the Eurocanards, and at the other extreme we have tailless platforms like the B-2. So-called "fifth generation fighters" all have higher RCS than the B-2 owing to their basic layout, yet we still call these aircraft "stealth aircraft". That Su-57 has a greater radar signature than other fifth-generation fighters tells us basically nothing about where it lies on this spectrum, let alone the operational implications in various dynamic contexts.

One thing we can be sure of, however, is that the designers of Su-57 are far more aware of the factors influencing RCS than lay observers are, and that the choices made are the product of careful judgments made according to specific operational requirements, cost/maintainability factors, and general design philosophies. As a general rule I don't second-guess the engineers of any nation. It is safe to assume that they know what they are doing. The question worth considering is, are they pursuing the right end? And frankly, I don't think there's enough information available to answer that.

Agreed completely. However you are also missing one factor in the choices made list. That is, the designers and engineers just couldn't do any "better". You're assuming they were able to 100% achieve everything the RuAF wanted from this project. So while the designers are indeed far more aware than we are, they also cannot determine the outcome of every technical challenge. They have to work within the limits of what they're capable of (by extension, also what resources were available etc). These limits could just be far more difficult to overcome than it was for other teams around the world. I'm not saying this is the case, but it is a valid point that needs to be included in this list of what the Russians could do. Saying the product is what it is because lay observers are more ignorant than the designers (of course) and because designers had the aim of achieving a certain quality of RCS reduction, they MUST have succeeded since that was their task and we don't know better than them, is fallacious.

Most of the more strident criticisms of Su-57 boil down to the simple logic that it is different to what the Americans have done and therefore it is wrong -- only with the novel twist that China is jumping on the bandwagon too. This is a nationalist and myopic perspective that will lead one astray as often as not, as it has on many previous occasions. None of this stuff has been validated in a peer threat environment, and until it has one should remain cautious about drawing conclusions that exceed the available data.

Woah I don't represent China. China doesn't have an opinion because China is not one individual entity. Chinese opinions on this matter are worthless as are everyone else's UNLESS they offer reasoning. Su-57 does still share some similarity to what the Americans have done. They've built a new generation fighter. The aim is VLO. Rest we don't know. Same with China. I'm certainly not someone who is criticising the Su-57 because it is "different" to what the Americans have done. Actually I think it is very similar to what Lockmart did. I'm simply weighing in on the discussion on Su-57 involvement in Syria. That led to a side-topic of its RCS characteristics.
 

ougoah

Brigadier
Registered Member
So unless the physics behind RCS reduction has changed or Russians found novel ways of achieving it (yet somehow still decided to follow the general concept of stealth shaping and made the effort to build internal bays), those characteristics of Su-57 make it an unstealthy fighter. It's possible they've managed to create other means of reducing its signature that is not visible to observers, BUT we cannot assume this is certainly the case just because there is a long held belief that everything Russian must be very capable, or whatever mysterious reason that makes us believe in the inherent superiority and capability of a group vs another.

So while it remains possible that Su-57 is a super duper fighter in ways we cannot tell, we never afford that luxury to the underdogs e.g. Chinese. In fact in regards to Chinese, it is the opposite, they've a mountain to overcome until the naysayers believe and even then, it is copied. While Russians definitely have a full stealth fighter despite available evidence suggesting otherwise.
 

Gloire_bb

Captain
Registered Member
that's the main parameter for being a 5 gen aircraft, reduced RCS,,,
Su-57 obviously has reduced RCS. It has very obvious shaping, unavailable to non-stealthy aircraft.

No, stealth is just one of the parameters. As important as everything else, but heavily conflicting with others.
 

Lethe

Captain
When I said obvious to the naked eye, I was referring to how easy it is for casual observers to see that the plane indeed has vents under its belly, protrusions of all sorts of stuff everywhere, two piece canopy, uneven surfaces on panels. More careful attention is paid on US stealth aircrafts to avoid all of these things. Unless these things don't matter to the RCS of a plane, it is therefore obvious to the naked eye that the Su-57 is not a stealthy fighter in the same regard as the LockMart products.

The problem is that folks are attempting to use a single term, "stealth", to describe a continuous spectrum of RCS. F-35 RCS management is inferior to F-22 RCS management which is inferior to B-2 RCS management, yet all of these aircraft are described as "stealth" aircraft. Yet that Su-57 (probably) has inferior RCS signature management to F-35 suddenly renders it "non-stealthy" -- why? The explanation seems to be because Su-57 is Russian. Why not instead say that anything more visible than a B-2 is non-stealthy? All of the very detailed -- and undoubtedly very dynamic -- analysis that could, in principle, support a clearer delineation of stealth vs. non-stealth is hidden from the public eye.

Agreed completely. However you are also missing one factor in the choices made list. That is, the designers and engineers just couldn't do any "better". You're assuming they were able to 100% achieve everything the RuAF wanted from this project.

I would indeed reject the notion that Sukhoi and other involved companies were unable to achieve parity owing to a deficiency in knowledge or technology. Indeed, its basic design characteristics are more advanced than its American equivalents, just as the Su-27 was over the F-15, which is unsurprising given the timelines involved and the historical strengths (and weaknesses) of Russian design bureaus. That is not to say that difficulties were not encountered. We already know that the structure had to be reinforced to deal with unexpected loads. No doubt there were other difficulties, and other items pushed back to a notional future development path.

The most likely drivers for any compromises that Russia has accepted are (1) cost and (2) design philosophy. The two-piece vs. one-piece canopy difference is very likely driven by cost. Regarding design philosophy, the United States is famously on its third-generation of stealth aircraft, yet even now the latest reports are that F-35's RCS coatings are difficult and labour-intensive to maintain, and this in largely pristine environments with manufacturer support directly on-hand. I would not be at all surprised if the reason Russia has not pursued a similar level of surface management is because they judge it impractical to maintain in a peer conflict scenario, and unnecessary for lesser conflict scenarios.
 
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Tirdent

Junior Member
Registered Member
Read the man's post again. Why bring J-20 into the discussion and not F-35 and F-22 as well then?? Those American planes have also been spotted with luneburg lenses. So why would he just "beg the question whether J-20 has some ECM"??

Because the US jets are known not to have active jammers which would be suitable for performing that function (beyond front-aspect, narrow-band electronic attack and/or towed decoys). So there simply is nothing interesting to discuss about them in this regard, but it prompted me to wonder about whether anything specific is known about the J-20 ESM/ECM suite.

Sure, wrong place to ask (as I admitted earlier), but I didn't anticipate such a strong reaction to an innocent question? I was not attempting to insinuate anything whatsoever one way or the other - just asking about a tangent the actual subject of the thread had inspired.

What has any of these other planes got to do with an alleged ECM on Su-57 that can cloak the fighter in some EM spectrum. BTW this is a totally idiotic thing to suggest.

Active RCS amplification by signal repeaters is a long-established technique in purpose-built target drones and air launched decoys (MALD, TALD). Hardly a science-fiction cloaking device. Granted, the hypothetical Su-57 system would have to be unusually wide-band, but then I expressly did not claim the idea to be anything more than speculation?

Okay so Su-57 is not stealthy in the league of the others. Therefore it must have something better up its sleeves. Ahh we have confirmation of this because it wasn't spotted with luneburg lense. Therefore it should have ECM. This somehow logically becomes, J-20 may not have ECM if luneburg lense were spotted. What kind of reasoning is this?

What kind of reasoning that is? Not mine - that's what. I never even suggested anything of the sort as a statement of fact but merely offered a *possible* reason why the Su-57 *might* not need a Luneburg lens and tried to pick people's brains on the J-20 ESM/ECM suite. Here are the actual quotes:

If the Su-57 retains dedicated active internal ECM (i.e. unlike the F-22 and F-35, which could only use the main radar in electronic attack mode [front aspect only and narrow-band] or towed decoys [can't drag those along for an entire flight]) it is possible that there is a signal repeater mode for RCS augmentation.

It just occurred to me while thinking about what compels the use of Luneburg lenses in the F-117, F-22 and F-35 (lack of all-aspect wide band jammers on board as a means to provide active RCS augmentation without a passive reflector) and why that might be different in the Su-57.

Within the bounds of the English language, I'm pretty hard-pressed to express even more clearly that it's just an idea, not a statement of fact. What more am I supposed to do in order not to invite accusations of idiocy and stupidity? That seems rather harsh, if I may say so.

It's not even a valid point of discussion given the topic of this thread.

Based on your apparent insistence on seeing some kind of conspiracy I am beginning to doubt whether asking the question in the J-20 thread instead would have made any difference whatsoever...

I'll reiterate for those who are intellectually challenged. Just because an aircraft sports luneburhg lenses does not mean it does not have ECM or other electronic means of spoofing sensors. Just because a fighter is spotted without LL, does not necessarily mean it does have ECM. That simple. Rest is off topic. Leave J-20 out.

If you are going to call me intellectually challenged you'd better be sure you've actually understood my reasoning. I charge you to point out where I'm supposed to have even implied that - if I genuinely thought the presence of a Luneburg lens proved the absence of an ECM system, why would I bother to ask the question on the J-20? Doesn't compute.
 
...

But I agree with "Red Samovar" that it is most likely a slightly modified T50-11:

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View attachment 45675 ...
"bmpd" says (at the bottom of
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) it's Т-50-11 which arrived at Zhukovsky in September of last year:
217663.jpg
 
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