Sukhoi PAK-FA / FGFA: Updates,News & Discussions

[sancho]

I totally agree with your point of view. As I said before, each single project has its own particularities. I just don't believe everybody who develops a fifth-generation fighter has to follow absolutely the same steps as the F-22. Of course, the Americans are showing the way, but even that didn't prevent the F-35 to be susceptible to detection by radars operating in the VHF bands of the spectrum.

That's the problem, people conclude too much based on looks and biased opinion. T50 generally will be claimed to be less stealthy, because of the belly, ignoring the fact that not even the F35 has a flat belly. They are critizing the (possible) missile bays at the wings, althought they are stealthy shaped as well, but not integrated into the fuselage like in the F22. But where is the critizism for the F35, that has no missile bays for SR misssiles at all, or that the B version has to carry an external gun pod with some shaping (is that a stealthier solution than the missile bay of the T50?), or that it also has refuelling systems or gun housing at the other versions, that are not integrated into the airframe but attached in shaped housings on top of the airframe too?

At the same time they also ignore the clear advances that the Russians came up with. They didn't "just" went for low RCS with stealth design, but also fielded the most advanced and capable fighter detection system that currently is available. There might be several stealth fighters in development, but afaik not a single other fighter that offers such capabilities in long range detection and wide field of view for the radar, besides the passive sensors that it fields all around the airframe. Even if we say the F22 is stealthier, it clearly falls short to detecting another stealth fighter, the way the T50 can!
It's long range radar is only aimed to the front, in a limited field of view and it's advanced EW sensors might be an advantage against current 4th gen fighters and their radars, but not against modern fighters with AESAs. If the F22 does not engage head on, it will find it more than difficult to gain the first sight advantage even against the current T50 prototypes.
There is hardly a 5th gen fighter that offers really so many NG capabilities or innovations at once and there are still many things to come, when the final Pak Fa / FGFA versions will arrive!

 

[danish_vij]

@he-man what do u think IAF and other important officials who know how to protect our country are fools ??? and u know everything?? cmmon man give it a break........dont talk shit if u dont have enough knowledge...unless u are an aeronautical engineer from an IIT or something
yea sometimes self criticism is cool but not every time u cant blabber about anything without iota of knowledge about it......
please look in points given up by @sancho @atlssa after removing cool self criticism

just show me any degree that u are qualified enough to understand the stealth technology or airframe.and i will all agree with u.....dont tell me u are just only internet warrior.....

and if u say it is not as advanced as f22 or f35 or whatever u think......but u should also know it is not as costly as f22 or f35
i guess we can buy 5t50's at the cost of 3 f22 or f35

 

[atlssa]

There is hardly a 5th gen fighter that offers really so many NG capabilities or innovations at once and there are still many things to come, when the final Pak Fa / FGFA versions will arrive!

Agreed!
To make a long story short: Stealthiness is not just about shaping! To design a low RCS airframe is kind of easy, however if you don't have the proper avionics for packing, it will be useless, or at most a 4G fighter with just a similar look of a 5G one.

The Russians are being very responsible within this matter. The most important fact for this kind of fighter is to be able to provide air superiority and air dominance. I don't have any doubts that T-50 will easily do so!

 

[atlssa]

and if u say it is not as advanced as f22 or f35 or whatever u think......but u should also know it is not as costly as f22 or f35

i guess we can buy 3 t50's at the same price as f35

Well, I don't believe it will be possible to buy 3 T-50 for the price of just one F-35 since its price shall go down a little bit in the next 2 years, but still T-50 will be affordable and very competitive.

Most of people who criticize the T-50 forget about how stealth technology began. Stealthiness is about low detectability, and to fully understand it we must look into the past.

SR-71 Blackbird was so fast it outran every missile and fighter jet encountered over enemy territory. In fact, neither enemy fighters nor enemy surface to air missiles were ever able to shoot down or to damage a SR-71. But the aircraft was never shot down also because it was hardly detected by enemy radars, being the first aircraft featuring stealth technology. Indeed, for the first time a special paint was used for Blackbird’s wings, tail and fuselage: since it contained iron ferrite, this paint absorbed radar energy instead of returning it to the sender.
If the only thing that matters was shaping, the SR-71 airframe could never be considered stealth. With an RCS of a small light aircraft, when the SR-71 was found on radar it was too late for a SAM computer to estimate its direction for a successful kill.
So, at that time, the SR-71 stealthiness was effective only because the Russians/Soviets didn’t have the proper technology to deal with him. Today, with the available technology, it would as detectable as an F-16!

In the 80s, the Americans came up with the USAF's Advanced Tactical Fighter (ATF) competition. Lockheed and Northrop were selected in 1986 to develop the YF-22 and the YF-23 demonstrator aircraft. Following a review of the flight test results and proposals, the USAF announced the Lockheed YF-22 as the competition winner on 23 April 1991.The YF-23 design was stealthier and faster, but the YF-22 was more agile. So, maneuverability is also important!
If you look at YF-23 airframe, more specific its underbelly, there are many differences in comparison with the F-22, still the YF-23 was considered the stealthier one.

In the 90s, with the JSF, the X-32 and X-35 were two totally different approaches for the program requisition, nevertheless both airplanes were stealthy.

As I said before, stealthiness is about low detectability. At the time of SR-71, the Russians didn’t have the proper technology to detect the plane within time enough to deploy the countermeasures. Nowadays, talking about the F-35, which is the world’s most expensive weapons program, the Russians already have in place the technology to detect, counter attack and shot down the aircraft. From this point of view we can say the SR-71 was more effective than the F-35. It all depends on the context you're looking to!

PAK-FA/FGFA is being developed considering all these aspects. It’s not about which aircraft has the sleekest underbelly, as our colleague @he-man suggested. It has to be effective, affordable, and able to provide air superiority and air dominance, and most of all, it has to match VVS and IAF requirements, which are the primary customers. Plain and simple! The rest is just BS of people who doesn't really know what they are talking about.

 

[he-man]

fair enough

 

[gambit]

There is a lot of baseless declarations about low radar observability in principles and about the Indian version of the PAK in particular, so am going to clear up some misconceptions...

In radar detection, the sphere is consider the ideal body because under radar bombardment, it radiate in a consistent manner. The sphere, of various diameters, is used to calibrate radar systems. With the sphere, we have specular reflection, and depending on the diameter's relationship with the operating frequency, the creeping wave behavior, which is a contributor to the sphere's RCS, may or may not appear.

This relationship is called the 'ten lambda' rule. Lambda is the Greek letter representing frequency or wavelength. If the diameter is greater than 10 times the wavelength (>10), the then creeping wave behavior will not occur. If the diameter is less than 10 times the wavelength (<10), then the creeping wave behavior will occur. So if we are going to calibrate an X-band radar, we should use a sphere whose diameter is >10 frequency in order to get only the specular reflection so we would know as precise as possible the amount of return.

Therefore, the sphere have at most two radiation methods: specular and surface waves.

Going to more complex bodies such as the cube...

The cube have the plate, or more like 6 plates. That is specular reflection. If we tilt a plate, as the angle of tilt increases surface waves behaviors will occur. But when the surface waves reaches a joint between plates, we have a surface discontinuity, the edge, which will give us the radiation mode of diffraction.

So for the left cube, we will have three radiation modes: specular, surface waves, and edge diffraction.

If we introduce curvatures into the cube, like in the right cube, we will still have the same three modes of radiation as the right cube, but less intense for edge diffraction and higher quantity of surface waves.

That means if we rotate both cubes, most likely the left cube will have a higher RCS and pulsating signature than the right cube. With curvatures, we can have better control of how radar signals will leave this finite body than with sharp edges.

So from these three bodies, we, meaning the US, have formulated the basic rules for designing/shaping complex bodies with RCS control in mind.

Control...
- Quantity of radiators
- Array of radiators
- Modes of radiation

The sphere have only its surface for quantity of radiators. The basic cube have two: the plate and edge. The pyramid also have two: the plate and edge. Remember, these are finite bodies, radar signals must leave a body somehow and some time.

On a complex body like an aircraft, major structures like flight control devices are radiators -- the plates. Because they are joined to the fuselage and are in close proximity to each other, this fall under the rule of 'control of array of radiators'. The B-2 have no vertical stabilators. This does not mean the B-2 ignored this rule. On the contrary, the B-2 obeyed this rule perfectly. The rule only say 'control' and part of control is not using a device if there is no need for that device.

When the F-117, F-22, F-35, PAK-FA, and the J-20 canted their vertical stabilators, they also obeyed the rule of 'control of array of radiators'. They canted their vertical stabilators to avoid the dreaded 90-deg corner reflector, which is a major no-no if we want to control final RCS.

The rules for the corner reflectors are:

- Avoid this structure completely.
- If not possible, then avoid the 90-deg type.

The B-2's design obeyed the first rule of the corner reflector structure. The designs for the supposedly 'stealthy' fighters obeyed the second rule of the corner reflector structure.

And both rules for the corner reflector structure falls under the higher rule of 'control of arrays of radiators'.

Once we go beyond this basic understanding, the discussion will involve higher order math and classified data because supercomputers are needed in order to make the complex body of an aircraft as obedient to the top three rules as much as possible.

For something like this...

The only solution is enclosure. A streamline pod that prevents any radar from impacting those structures still obeys those three top rules of RCS control.

So what are we to make of the situation when we have three supposedly 'stealth' fighters that based upon visual inspection, seemingly obey the rules of RCS control to high degree ?

At this point, we have to inspect their bodies at finer granularity. Everything from the degree of curvatures anywhere to panel gaps to fastener heads.

The reason is this...

The above is how any radar system 'sees' an aircraft: as a cluster of voltage spikes created by structures, major and minor, on the aircraft. For the example above, the highest spike came from the tail section, obviously. We can also see a cluster created by the three engines.

One alleged 'stealth' fighter may have its shaping in some ways kept it above the threshold. The J-20 have two ventral fins (control of quantity of radiators) that do not exists on the F-22 and the PAK. Would those structures raise the J-20 above the clutter rejection threshold when they are in the radar stream ? Possibly. We can argue that in the absence of hard data, the J-20 may very well be as 'stealthy' as the F-22, but the first rule of RCS control -- control of QUANTITY of radiators -- suggests otherwise. The J-20 did not 'violate' this rule. It just did not obey the rule to the same degree as the F-22 does.

The same rules applies to the engine exhausts on all three aircrafts. It is very rare that any radar would have a direct view of the engine exhaust. From this perspective, even the F-22 will be detected. But precisely because it is so rare a situation, the F-22's engine exhausts are designed to be more recessed and better shaped than its competitors so that in the oblique angles, the engine exhausts are less detectable than those on its competitors.

Remember, the rules are:

Control...
- Quantity of radiators
- Array of radiators
- Modes of radiation

We do not 'violate' any rule. We just have varying degrees of OBEDIENCE to them.

This means the sphere is the near perfect 'stealth' body. This also means that based upon informed opinion, despite the absence of hard data, the J-20 may have a slight edge in terms of better OBEDIENCE to the RCS control rules than the PAK.

 

[gambit]

As an addendum to post 1941...

U-2 plane fooled new computer system, halting flights in California - CNN.com

A very old spy plane and a very new computer system played pivotal roles in last week's computer glitch that temporarily paralyzed flight operations in southern California, officials tell CNN.

The problem involved a U-2 aircraft, the type famed for conducting reconnaissance missions over the Soviet Union during the Cold War.

A Federal Aviation Administration computer system interpreted the U-2's flight path at a very high altitude as if it were flying in a much lower and more crowded airspace.

The computer -- which anticipates the flight path and looks for possible conflicts such as other aircraft or restricted airspace -- was overtaxed by the many flight changes the U-2 had plotted, officials said.

That work used much of the computer's memory and interrupted its other flight-processing functions, FAA spokeswoman Laura Brown said in a statement.

The agency said it has added computer memory to prevent a recurrence, while others said officials are racing to install a more permanent computer patch.

While this may seems unrelated to 'stealth' discussions, it is more subtly relevant than most realize.

For this incident, the FAA's computer that processes air traffic radar data did not have sufficient resources, hardware and software, to accurately process the variable call 'U-2'. This aircraft flew high and had so many waypoints that this variable confused the entire data processing capability.

This is what 'stealth' does: confuse the seeking radar as to what it is 'seeing'.

The intent of 'stealth' is to submerge the aircraft into the clutter region where the seeking radar either rejects the entire region, which would discard the 'stealth' aircraft in the first place, or attempts to process every single signal inside that region and if there are known clutter signals such as cloud or flora or terrain, the radar will be confused, just like how the FAA air traffic radar computer failed to accurately process the U-2's flight.

Have no doubt that the 'stealth' aircraft will be detected. But it will be processed as if it is a legitimate clutter signal among the millions of other low level signals that make up the clutter region.

 

[he-man]

That's the problem, people conclude too much based on looks and biased opinion. T50 generally will be claimed to be less stealthy, because of the belly, ignoring the fact that not even the F35 has a flat belly. They are critizing the (possible) missile bays at the wings, althought they are stealthy shaped as well, but not integrated into the fuselage like in the F22. But where is the critizism for the F35, that has no missile bays for SR misssiles at all, or that the B version has to carry an external gun pod with some shaping (is that a stealthier solution than the missile bay of the T50?), or that it also has refuelling systems or gun housing at the other versions, that are not integrated into the airframe but attached in shaped housings on top of the airframe too?

At the same time they also ignore the clear advances that the Russians came up with. They didn't "just" went for low RCS with stealth design, but also fielded the most advanced and capable fighter detection system that currently is available. There might be several stealth fighters in development, but afaik not a single other fighter that offers such capabilities in long range detection and wide field of view for the radar, besides the passive sensors that it fields all around the airframe. Even if we say the F22 is stealthier, it clearly falls short to detecting another stealth fighter, the way the T50 can!
It's long range radar is only aimed to the front, in a limited field of view and it's advanced EW sensors might be an advantage against current 4th gen fighters and their radars, but not against modern fighters with AESAs. If the F22 does not engage head on, it will find it more than difficult to gain the first sight advantage even against the current T50 prototypes.
There is hardly a 5th gen fighter that offers really so many NG capabilities or innovations at once and there are still many things to come, when the final Pak Fa / FGFA versions will arrive!

even with a head on engagement f-22 will find it hard to detect pakfa first simply because pakfa will have a better radar than old apg-77 which has been too much glorified.The current benchmark for radar tech will be apg-81,i can bet my money on it.

as for ur points on ew systems and radars go,,,its true that no other aircraft can match the amount of sensors that are going into pakfa,,,i mean it will have at least 270 degrees of aesa coverage even without a rear radar and well 360 with a rear aesa which will be there for indian fgfa most probably.
4 th gen or even 4.5 gen stuff stand no chance whatsoever against pakfa,,,its just too damn full of sensors and if the reports of idz 30 engine generating 180 kn in wet mode are true then well the plane will be virtually unbeatable in air-air mode.

Not to say that f-35 is less advanced,,,on the contrary apg-81 should be better than n036 based on the americn experience in the aesas,its their 4 th gen aesa after apg-77,79,80 etc so yeah they have shit load of experience.But in terms of power and detection range just due to its sheer size n036 will have huge,,,i mean>400 km detection range.Even irbis e has claimed a detection range of 400 km against 3 m2 target and 90 km for .01 m2 so yeah all the things point to a kickass radar in the form of n036.

As far ar irst goes,,lets hope russians catch up as in this world of stealth irst has suddenly become very very important to detect another stealth plane but no data is available still.
So all in all pakfa will be an awesome bird vs anything in the air,,there is no doubt about it but it will not be that good against the ground radars with that underbelly.That was the whole point of discussion,u conveniently ducked it for a more holistic approach

 

[gambit]

even with a head on engagement f-22 will find it hard to detect pakfa first simply because pakfa will have a better radar than old apg-77 which has been too much glorified.The current benchmark for radar tech will be apg-81,i can bet my money on it.

as for ur points on ew systems and radars go,,,its true that no other aircraft can match the amount of sensors that are going into pakfa,,,i mean it will have at least 270 degrees of aesa coverage even without a rear radar and well 360 with a rear aesa which will be there for indian fgfa most probably.
4 th gen or even 4.5 gen stuff stand no chance whatsoever against pakfa,,,its just too damn full of sensors and if the reports of idz 30 engine generating 180 kn in wet mode are true then well the plane will be virtually unbeatable in air-air mode.

Not to say that f-35 is less advanced,,,on the contrary apg-81 should be better than n036 based on the americn experience in the aesas,its their 4 th gen aesa after apg-77,79,80 etc so yeah they have shit load of experience.But in terms of power and detection range just due to its sheer size n036 will have huge,,,i mean>400 km detection range.Even irbis e has claimed a detection range of 400 km against 3 m2 target and 90 km for .01 m2 so yeah all the things point to a kickass radar in the form of n036.

As far ar irst goes,,lets hope russians catch up as in this world of stealth irst has suddenly become very very important to detect another stealth plane but no data is available still.
So all in all pakfa will be an awesome bird vs anything in the air,,there is no doubt about it but it will not be that good against the ground radars with that underbelly.That was the whole point of discussion,u conveniently ducked it for a more holistic approach

The F-22 have been called an 'antenna farm' for good reason...

It can fight completely silent.

 

[danish_vij]

Well, I don't believe it will be possible to buy 3 T-50 for the price of just one F-35 since its price shall go down a little bit in the next 2 years, but still T-50 will be affordable and very competitive.

thanx for info.....just checked wiki now
edited it was a guess.......

 

[he-man]

The F-22 have been called an 'antenna farm' for good reason...

It can fight completely silent.

untill its thoroughly modernized,,it cannot compete even with f-35.

if its modernized its unbeatable for sure,everyone knows it

 

[atlssa]

So all in all pakfa will be an awesome bird vs anything in the air,,there is no doubt about it but it will not be that good against the ground radars with that underbelly.That was the whole point of discussion,u conveniently ducked it for a more holistic approach

What you missing here the fact that no fighter, despite of its underbelly, will still be undetectable anymore, not even the F-22.
In fact, depending on range, any radar can eventually "see" a stealth aircraft when they get close enough. It’s not about a beauty context, it’s about effectiveness.

Long wave is no good for fire control. Fire control radar is actually what paints the target and guides a missile.
15 years ago a dead broke former soviet satellite state (Yugoslavia) brought down an F-117 "stealth" with a Cuban missile crisis era SAM. The F-177 had the sleekest underbelly at all.

Stealth is not magic. It can be defeated!

The main difference is all the electronic counter-measures in the new jets. They can jam surface to air missiles, jam the ground radar, they can emit huge EMP, disable their electronics. To stay undetected, the effective stealth fighter must have very long range radar systems that can detect enemy radar long before they are seen, and jam it, or take it out with long range missiles. Without it, every single stealth fighter is useless.

Despite of its shaping, it must have the proper packing (avionics) to be effective in the skies, or it will be only good as a wallpaper on someone computer’s desktop.

You've made up your mind about the T-50 underbelly, which of course its important, but not as crucial as you said, if you consider all the other features the airplane must have. It's obvious the Russians didn't sacrifice that for nothing. I will repeat one more time, it's about effectiveness, and to achieve that there are many other details that must be observed.

 

[he-man]

What you missing here the fact that no fighter, despite of its underbelly, will still be undetectable anymore, not even the F-22.
In fact, depending on range, any radar can eventually "see" a stealth aircraft when they get close enough. It’s not about a beauty context, it’s about effectiveness.

Long wave is no good for fire control. Fire control radar is actually what paints the target and guides a missile.
15 years ago a dead broke former soviet satellite state (Yugoslavia) brought down an F-117 "stealth" with a Cuban missile crisis era SAM. The F-177 had the sleekest underbelly at all.

Stealth is not magic. It can be defeated!

The main difference is all the electronic counter-measures in the new jets. They can jam surface to air missiles, jam the ground radar, they can emit huge EMP, disable their electronics. To stay undetected, the effective stealth fighter must have very long range radar systems that can detect enemy radar long before they are seen, and jam it, or take it out with long range missiles. Without it, every single stealth fighter is useless.

Despite of its shaping, it must have the proper packing (avionics) to be effective in the skies, or it will be only good as a wallpaper on someone computer’s desktop.

You've made up your mind about the T-50 underbelly, which of course its important, but not as crucial as you said, if you consider all the other features the airplane must have. It's obvious the Russians didn't sacrifice that for nothing. I will repeat one more time, it's about effectiveness, and to achieve that there are many other details that must be observed.

dude i know all this these things,,,u are taking me for a novice which i am not.

the point of comparison is word relative.

and the way i see it,,,pakfa is relatively more vulnerable to ground based radars than sau f-22,f-35 and j-20.

and for the other features i have written on that in my above post,,,pakfa will be near impossible for anything to defeat in air except a modernized f-22 for obvious reasons but it has its share of flaws,,,every bird has one

 

[atlssa]

u are taking me for a novice which i am not

I never said you're a novice. So please calm down!

As I said before, ground base radars already are effective against stealth aircraft, all of them. In the case T-50 would have an underbelly as sleek as the F-22, it would still be detected, unless it is well equipped. It is the same with all the other 5G fighters, including the F-22 itself.

The only way I agree with you is if we compare just the airframes, with no avionics whatsoever. In this case, and only this, the F-22 shape is more effective than T-50. Since the aircraft has many other features that can’t be ignored, there is no point to steak with this detail.

But I got you... you have the right of disliking the way it looks like.

 

[sancho]

That was the whole point of discussion,u conveniently ducked it for a more holistic approach

Lol, explaining to you the features the Russians used at the belly to reduce the RCS is ducking? You don't have even any point here, other than that you don't like the belly design, but your preference doesn't mean that there is an issue wrt RCS or ground radars. But that's just another conclusion you ran into, just based on looks and your theories. One of the few that we have seen from you in the last few weeks on many topics isn't it?