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Thread: Su-57/T-50/PAK-FA/FGFA News/Discussion 08/2017

  1. #121
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    @garryA

    Maybe ITO maybe something else, my point is it is different then JSF pole model (which didn't had EOTS at all, instead it had EOTS shape protrusion covered with RAM) and different then marketed golden EOTS. So that isn't problem because we want to believe it is super stealth because it is facet (which "only" Americans can make) but much smaller OLS is problem because it isn't facet even though when it isn't in use it is RAM covered sphere.
    Last edited by Krivakapa; 16th September 2017 at 10:26.

  2. #122
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    @mig-31bm

    Some points:

    - I assumed 5-10 dbsm reduction for RAM based on the publications I have and you claim 15-20 dbsm reduction based on that study. I won't argue about it, too uncertain.

    - Its possible that an assumed RAM penalty is already included in paralays optical scattering plot. Certain is that there are physical boundaries for RAM performance, so professionals can make reasonable assumptions about its performance. I also won't argue whether such a penalty is included in paralays plot, only he can.

    - Yes the F-16 has a quite special signature low cones around 45 off boresight in range of 0,5m RCS. Frontally however it is fully conventional with 5-10m. The F-22 on the other hand, always remains below 1m for 150 frontal aspect i.e a full stealth design.
    I'm not saying that the Russian claim for 0,3m average frontal is true, but at least this source this source is also critical towards its own Su-57. If you for some reason want to know my opinion, I think the tactically exploitable low spike cones are a magnitude lower than 0,3m. The Russian statement of 0,3m frontal average could be true, as well as a LM claim of pea size (-50 dbsm) RCS local-minimum for a ~3-5 cone. Both statements could be true at the same time while the tactical usefulness of 5 cone is questionable.

    - Escort fighters being on stations 50-100km in front or side of the AEW aircraft is reasonable. To fly around the group and outflank it, you also need the range reserves to do it. Lets say at increasing numbers of sensors and distances between them, to remain undetected via the low RCS cone approach is become increasingly difficult and and overall spikeless frontal average becomes important.

  3. #123
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    @mig-31bm
    57 km? Not such a great feat, the plane you have taken your nickname from standard flight formation envisage a distance of more than 100km between each plane of a flight of four so to maximize the scanned area.
    About the unexpected approach direction, it seems me that you can't free your mind by the preconception that the most part of enemy air defence positions would be know with precision beforehand.
    It's almost a pair of decades that it's not more like so, actual SAM systems (from S-300S onward) are highly mobile, with a set up /dismount time of few minutes and their crews are specifically trained to be always on the move so a great part of the AD network would ever be unbeknowst by the attackers either.
    What is however certain is that almost all those systems would be positioned in a way to overlap and cover one with the other.

    This not to say, as some overenthusiastic RUSSIASTRONKists sometimes do that stealth is of a sudden useless, just that it is a mean to an end, not an end in itself.
    Let's say the initial out of this world expectatives that have lead to planes as F-117 and B-21 and in great part also the F.-22 cannot anymore and by a long time (and IMHO the USAF was perfectly aware of that) be fulfilled.
    Same I would say of the suicide idea that a stealth plane could just sneak between two Ad radar "black hole" in order to penetrate deeper.
    Let aside that, as said above those radars respective position could hardly be given for granted, as soon as said plane try to pass between them, sides would be exposed and so the supposed black hole would not exist anymore.
    Attached Images Attached Images  

  4. #124
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    Quote Originally Posted by PeeD
    I assumed 5-10 dbsm reduction for RAM based on the publications I have and you claim 15-20 dbsm reduction based on that study. I won't argue about it, too uncertain.
    That the whole point, there are hundreds different types of RAM and the different between their absorbing capabilities can be as high as 15-25 dBsm. Not to mention the effect of RAS. You can't make any solid conclusion about RCS without information about the kind of RAM and RAS that these fighters use. A radar scattering chart give you the general idea of high RCS aspect and that where it stop.

    Quote Originally Posted by PeeD
    - Its possible that an assumed RAM penalty is already included in paralays optical scattering plot. Certain is that there are physical boundaries for RAM performance, so professionals can make reasonable assumptions about its performance. I also won't argue whether such a penalty is included in paralays plot, only he can.
    It isn't paralay's plot, it is a plot from a Chinese university's study. I downloaded their full PDF before, they didn't mention anything about RAM, just standard mesh simulation. I will try to dig it up for you.

    Quote Originally Posted by PeeD
    - Yes the F-16 has a quite special signature low cones around 45 off boresight in range of 0,5m RCS. Frontally however it is fully conventional with 5-10m. The F-22 on the other hand, always remains below 1m for 150 frontal aspect i.e a full stealth design.
    I'm not saying that the Russian claim for 0,3m average frontal is true, but at least this source this source is also critical towards its own Su-57. If you for some reason want to know my opinion, I think the tactically exploitable low spike cones are a magnitude lower than 0,3m. The Russian statement of 0,3m frontal average could be true, as well as a LM claim of pea size (-50 dbsm) RCS local-minimum for a ~3-5 cone. Both statements could be true at the same time while the tactical usefulness of 5 cone is questionable.
    The region where F-16 RCS reaches 5-10 m2 is only ~4-5 cone, it still get the average RCS of only 0.52m2. That why i have problem with Russian claims. It doesn't explain the feat achieved by stealth aircraft, and it doesn't make sense for them to spend billions dollars for only 5-6% reduction in radar detection range


    Quote Originally Posted by PeeD
    Escort fighters being on stations 50-100km in front or side of the AEW aircraft is reasonable. To fly around the group and outflank it
    I don't suggest stealth fighter will fly around to flank them, i suggests what if they fly from unexpected direction. For example: if your spread out formation is prepared for enemy comming from the North but they instead comming from the West or North West. What now?
    Last edited by mig-31bm; 16th September 2017 at 18:03.

  5. #125
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    I trust Russian specialists in this field to Lagarkov and Pogosyan. They say that a fifth generation fighter, due to constructive features, can not have a RCS below 0.3 m2
    OMG!!!


  6. #126
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    @mig-31bm
    57 km? Not such a great feat, the plane you have taken your nickname from standard flight formation envisage a distance of more than 100km between each plane of a flight of four so to maximize the scanned area
    mig-31bm is two decades old name and seem it stuck there.

  7. #127
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    Quote Originally Posted by Marcellogo
    57 km? Not such a great feat, the plane you have taken your nickname from standard flight formation envisage a distance of more than 100km between each plane of a flight of four so to maximize the scanned area.
    57 km spread formation if you want to stay outside the 30 cone at distance 100 km, if you want to stay outside the cone at longer distance then your formation will have to spread wider. Simple geometry.
    Anyway, i dont think you get the point. Mig-31 is a interceptor, it rarely do anything else. The main opponents of Mig-31 are B-1, B-52, Cruise missiles, Recon aircraft. In short, those one doesn't fight back. These opponents are not maneuverable either so Mig-31 can launch it's massive missiles from very long range. It is also one of the few aircraft that cruise at Mach 2.8-3. So it is acceptable to thin out Mig-31 force and make them fly 100 km apart because even if you put a single Mig-31 against 6 B-52, the B-52 still have no way to shot it down.
    By contrast, if your fighter squadron face another fighter squadron with 2-3 times your number. That will not end well.
    Quote Originally Posted by Marcellogo
    About the unexpected approach direction, it seems me that you can't free your mind by the preconception that the most part of enemy air defence positions would be know with precision beforehand.
    It's almost a pair of decades that it's not more like so, actual SAM systems (from S-300S onward) are highly mobile, with a set up /dismount time of few minutes and their crews are specifically trained to be always on the move so a great part of the AD network would ever be unbeknowst by the attackers either.
    What is however certain is that almost all those systems would be positioned in a way to overlap and cover one with the other.
    I know modern AD networks can change their position but they are still ground forces and long range SAM like S-300, S-400 do not shoot on the move.An air forces can change their routes at much faster rate than any ground force can reallocate. That why i said tactics can go both ways.

    Quote Originally Posted by Marcellogo
    Same I would say of the suicide idea that a stealth plane could just sneak between two Ad radar "black hole" in order to penetrate deeper.
    Let aside that, as said above those radars respective position could hardly be given for granted, as soon as said plane try to pass between them, sides would be exposed and so the supposed black hole would not exist anymore.
    Not so simple, earlier i said side aspect RCS is less important compared to frontal or tail aspect RCS, and that is for good reason.
    Radar performance degrades at viewing angles where a target must be distinguished from background clutter. Most radar energy is transmitted and received via a main lobe aligned with the antenna’s boresight, but smaller amounts enter through sidelobes that point in almost all directions. Clutter can enter the receiver via the sidelobes, and the processor has no way of knowing the return did not come from the main lobe. Such returns can mask that of the target.

    Modern radars mitigate this phenomenon with Doppler processing. A pulse-Doppler radar records the time of arrival of a return and also compares its phase with that of the transmitted wave. The difference between the two reveals the target’s radial velocity. The computer creates a 2D range/velocity matrix of all returns, which puts approaching targets in cells with no stationary ground clutter. This is why airborne radars exhibit their best detection ranges against approaching targets.But if the target is being chased, its radial velocity will match some of the ground clutter, and it will be harder to detect. For example, the Sukhoi Su-35’s Irbis-E radar in high-power, narrow-beam search can detect a 3-m2 (32-ft.2) target at 400 km (250 mi.) from the front but only 150 km from behind, and these ranges drop by half in normal search mode. The hardest airborne targets to see are those moving perpendicular to the radar, because their Doppler profile matches the ground directly below the aircraft.
    For ground-based radars, the same principles apply, but the antenna is stationary. Fleeing targets stand out as much as approaching aircraft. But ground-based radars are especially challenged in detecting targets moving perpendicularly, because their Doppler profile matches the stationary clutter all around. A tactic used by fighter pilots against ground radars, called “notching,” is to turn perpendicular to the radar, placing the aircraft in the “Doppler notch” in which the radar suffers significantly reduced range.
    http://m.aviationweek.com/aviation-w...-cranked-kites
    Last edited by mig-31bm; 16th September 2017 at 17:59.

  8. #128
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    The F-16 RCS is based upon a model. Most cases, models aren't exactly the same as the full unit itself in real world tests. But the model gives a good idea. But as said in the pictures above, average would be 1.2m^2. Although, what is the validation of that, I don't know. In a lot of cases, nations like Venezuela and the like would have tested their F-16's against their Su-30MK2's and would have obtained good data, one of which they would have shared since they have little good relations with the US. In this case, gives good insight to other parties (be it China or Russia) on it.

    A lot of this stuff, like RCS and what not are usually kept tight lipped. We are getting estimates but yeah, I highly doubt most claims of RCS from everyone. They will make a tale but they won't give up all details for obvious reasons.

  9. #129
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    Very good information mig-31bm.

  10. #130
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    @mig-31bm

    The F-16 is a special case as said. It has 4 sub 1m RCS lobes of ~45 distributed around the aircraft. For the rest of the 180 it is above 1m RCS. Frontally it has a conventional 30 lobe with above 1m. This all can be tactically exploited with a high electronic awareness.
    The F-22 on the other hand has, as said, a ~140 lobe to its front with sub 1m RCS (RAM not included). It has the same conditions for 70 of it's rear, which the F-16 does not, enabling effective fleeing from a chasing opponent. The tactical flexibility this offers can be used in a much more effective way, impossible for the F-16. The F-35 lacks a all-aspect capability of the degree of the F-22, but is equally strong for the frontal 120. Being able to direct towards the treat emitter to kill it (evade it for ARH AAM) is a much more applicable tactic than try to fly at 30 to the emitter as the F-16 would have to.
    So despite local low RCS cones of non-stealth design, they would have very different tactical capability and RAM is not included.

    I don't suggest stealth fighter will fly around to flank them, i suggests what if they fly from unexpected direction. For example: if your spread out formation is prepared for enemy comming from the North but they instead comming from the West or North West. What now?
    That would be flanking. Stealth fighters have of course better chances for flanking. In the context of KJ-2000 and escorting J-10 being killed by J-20, the J-10 would have to operate in a special search pattern with the right distances and right radar direction cycles. At least if a multi-sensor defeat is necessary for the stealth opponent. In total operation outside a friendly advanced ground IADS, without exotic assets such as OTH radars, is the realm where stealth fighters become most potent. The lack of a AEW asset, sensor networking/fusion, lack of ELINT and emission control, drastically increase the threat posed by a stealth fighter.



    As for radar performance against fleeing and perpendicular targets. I wonder how the author knows about the Irbis-E performance for a fleeing target? low processing power and analog signal processing with high false alarm rate were the main reasons for such low performances. Side lobes another.
    Today there are very effective solutions for both. High processing power and digital signal processing allow advanced digital MTI to detect even smallest doppler shifts and for ground based radars only a accurate perpendicular flight could cause that effect, not fleeing ones. Sidelobe canceling and high gain antennas pointing towards the sky are other methods now in use to avoid problems caused by clutter.
    The perpendicular effect would be just depended on the MTI filter settings/methods in a modern ground radar and effective in just a small angular band. But the fleeing case certainly has a detectable doppler shift, so I wonder what the bottleneck with the Irbis-E would be for more than 100% range reduction, I doubt it is the processing power like in Soviet 80's radar. Once the MTI filter accepts the doppler shift level and classifies it as moving target (not false alarm), just the reflected RF energy counts. Possible that the figures were just for a fighter target (frontal 3m RCS) which would normally have lower rear RCS with possible plasma effects when afterburning (typical fleeing scenario).

  11. #131
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    Quote Originally Posted by PeeD
    The F-16 is a special case as said. It has 4 sub 1m RCS lobes of ~45 distributed around the aircraft. For the rest of the 180 it is above 1m RCS. Frontally it has a conventional 30 lobe with above 1m. This all can be tactically exploited with a high electronic awareness.
    The F-22 on the other hand has, as said, a ~140 lobe to its front with sub 1m RCS (RAM not included). It has the same conditions for 70 of it's rear, which the F-16 does not, enabling effective fleeing from a chasing opponent. The tactical flexibility this offers can be used in a much more effective way, impossible for the F-16. The F-35 lacks a all-aspect capability of the degree of the F-22, but is equally strong for the frontal 120. Being able to direct towards the treat emitter to kill it (evade it for ARH AAM) is a much more applicable tactic than try to fly at 30 to the emitter as the F-16 would have to.
    So despite local low RCS cones of non-stealth design, they would have very different tactical capability and RAM is not included.
    You misread the graph. The whole graph is only for +/-45 frontal sector rather than all around scattering of F-16. That frontal conventional lobe is around 4-5. It has many low RCS lobes too. But that isn't my point, the point is average RCS value tell you next to nothing and i have explained why it is so. If you think average RCS is what count then remember a conventional small fighter like F-16 has average RCS only slightly higher than the Russia claimed average RCS value for all stealth aircraft. Use your critical thinking for a minute, would everyone spent billions on stealth technology if they can only get 5-6% detection range reduction?.



    Quote Originally Posted by PeeD
    That would be flanking. Stealth fighters have of course better chances for flanking. In the context of KJ-2000 and escorting J-10 being killed by J-20, the J-10 would have to operate in a special search pattern with the right distances and right radar direction cycles. At least if a multi-sensor defeat is necessary for the stealth opponent. In total operation outside a friendly advanced ground IADS, without exotic assets such as OTH radars, is the realm where stealth fighters become most potent. The lack of a AEW asset, sensor networking/fusion, lack of ELINT and emission control, drastically increase the threat posed by a stealth fighter.
    Flanking is the strategy when your force go around behind enemies, in my example stealth fighters simply approach from a different direction instead of exactly where you think they will come from.

    Let say your squadron spreading out to prepare for enemies coming from the North, but instead they come from North West or West North West or North East or East North East.. Etc.
    Your opinion sounds like stealth is a big conspiracy, all contries developed stealth make pilots of conventional fighters do certain stuff so that their stealth fighter could prevail in test. But if we counting facts, there is no evidence to say J-10 radar need to operate at some special mode so that their AWACs could be killed by J-20. All recent exercises against stealth fighters, they have used AWACs, network of SAM, jamming, and even go as far as putting dedicated IRST pod on aircraft. In short, if Russia, China, USA, India and many others countries trying to make stealth aircraft then iam sure they have good reasons for that.

    Quote Originally Posted by PeeD
    As for radar performance against fleeing and perpendicular targets. I wonder how the author knows about the Irbis-E performance for a fleeing target? low processing power and analog signal processing with high false alarm rate were the main reasons for such low performances. Side lobes another.
    Today there are very effective solutions for both. High processing power and digital signal processing allow advanced digital MTI to detect even smallest doppler shifts and for ground based radars only a accurate perpendicular flight could cause that effect, not fleeing ones. Sidelobe canceling and high gain antennas pointing towards the sky are other methods now in use to avoid problems caused by clutter.
    The perpendicular effect would be just depended on the MTI filter settings/methods in a modern ground radar and effective in just a small angular band. But the fleeing case certainly has a detectable doppler shift, so I wonder what the bottleneck with the Irbis-E would be for more than 100% range reduction, I doubt it is the processing power like in Soviet 80's radar. Once the MTI filter accepts the doppler shift level and classifies it as moving target (not false alarm), just the reflected RF energy counts. Possible that the figures were just for a fighter target (frontal 3m RCS) which would normally have lower rear RCS with possible plasma effects when afterburning (typical fleeing scenario).
    Even digital signal processing will not change the fact that all radars have much longer range against closing target than flee or notching target. The cause is signal/noise ratio due to side lobes and clutters.


    Consider fighter radar, flee targets will have the same or very similar Doppler shift as your side lobes reflection, so you need higher S/N ratio to detect target => shorter range. A target flying perpendicular to you will have the same or very similar Doppler shift as the ground underneath it. Reduce your speed gate isn't a good course of decision because you will have significantly higher false alarm.
    For surface radar, fleeing targets aren't a problem, but aircraft fly perpendicular will have the same Doppler shift (no shift) as the ground underneath it and also the side lobes reflection of the radar. Side lobes can be reduced but can't be eliminated completely even with your radar 90 up.

    Ground radars are affected more by side lobes reflection compared to fighters radar because their aperture is only 15-20 meters from ground so reflections are very strong.

    Consider modern AESA such as Zhuk-AE, the differences is still there.
    Zhuk-AE can detect aerial targets at ranges up to 130 km (head on) in both look-up or look down modes. Look-up tail-on detection range is 50km
    The Zhuk AE can detect a destroyer size target at a range of 200 km.
    http://defense-update.com/features/d...ar_zhuk_AE.htm

    The Irbis-E has much shorter range against ground and sea targets even though a ship RCS is much bigger than aircraft RCS


    P/s: jet engine isn't hot enough for the plasma effect.
    Last edited by mig-31bm; 18th September 2017 at 12:54.

  12. #132
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    Why you are posting outdated information about MIG radars?
    Newer one without GaN has so much range for export.
    http://www.janes.com/article/65271/a...mig-35-fighter

  13. #133
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    Quote Originally Posted by JSR
    Why you are posting outdated information about MIG radars?
    Newer one without GaN has so much range for export.
    You missed the point. I want to show him the difference between detection range of closing and fleeing target
    Quote Originally Posted by RALI
    Very good information mig-31bm
    Thanks you.
    Last edited by mig-31bm; 18th September 2017 at 08:58.

  14. #134
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    @mig-31bm

    I have never said that the average RCS should be considered to judge stealth designs performance. Nor do I use the F-16 RCS plot you provided but that of the Sukharevsky's publication on RCS. I'm not even saying that the 0,3m claim from Russian side is true and I don't know what they meant exactly. In my previous post I pointed out the advantages of stealth with the F-22 as example. We have different views on the performance levels and tactical application but even Russians have developed a stealth design despite their 0,3m claim.

    Flanking is the strategy when your force go around behind enemies, in my example stealth fighters simply approach from a different direction instead of exactly where you think they will come from.

    Let say your squadron spreading out to prepare for enemies coming from the North, but instead they come from North West or West North West or North East or East North East.. Etc.
    It translates into flanking. A F-35 detects the opponent first and tries to avoid his radar by approaching it inside his low RCS lobes. He more or less knows at what threshold the enemies radar would detect it, so he either kills it outside that envelope or fly/flanks it outside the opponents scan field. Anyway, yes stealth offers this tactical advantage.

    Your opinion sounds like stealth is a big conspiracy, all contries developed stealth make pilots of conventional fighters do certain stuff so that their stealth fighter could prevail in test. But if we counting facts, there is no evidence to say J-10 radar need to operate at some special mode so that their AWACs could be killed by J-20. All recent exercises against stealth fighters, they have used AWACs, network of SAM, jamming, and even go as far as putting dedicated IRST pod on aircraft.
    In exercises and simulated engagements the rules of engagement/parameters can be defined as deemed appropriate, its not about conspiracy theory.
    Both, J-20 and F-22/-33 need to perform several magnitudes better than the Russian claim of 0,3m (unknown definition) to approach a high power radar of a AEW aircraft undetected (what range?).
    I go for one added magnitude due to RAM/RAS and you go for several magnitudes due to it.
    There are too many unknowns about the simulated engagements, about RAM/RAS performance and about non-simulated reality effects such as traveling waves etc.

    In short, if Russia, China, USA, India and many others countries trying to make stealth aircraft then iam sure they have good reasons for that.
    Never said anything else. But we differ on the performance level.

    Even digital signal processing will not change the fact that all radars have much longer range against closing target than flee or notching target. The cause is signal/noise ratio due to side lobes and clutters.
    Again its about the "how much", 2/3 reduction as your article claims or less in modern radars?

    Consider fighter radar, flee targets will have the same or very similar Doppler shift as your side lobes reflection, so you need higher S/N ratio to detect target => shorter range. A target flying perpendicular to you will have the same or very similar Doppler shift as the ground underneath it. Reduce your speed gate isn't a good course of decision because you will have significantly higher false alarm.
    I already mentioned array active sidelobe cancelling etc. and there are more such as space-time adaptive processing. This is basically a hard and software problem, much less a physical one. Today there are enough solutions to avoid a 2/3 range performance collapse because the dopplershift of the fleeing target can't be measured good enough.

    For surface radar, fleeing targets aren't a problem, but aircraft fly perpendicular will have the same Doppler shift (no shift) as the ground underneath it and also the side lobes reflection of the radar. Side lobes can be reduced but can't be eliminated completely even with your radar 90 up.

    Ground radars are affected more by side lobes reflection compared to fighters radar because their aperture is only 15-20 meters from ground so reflections are very strong.
    This is a physical effect that indeed occurs in a very special and small region. The question is what dopplershift the ground radar can measure. If its high enough via techniques like STAP, the ability to tactically exploit it, decreases to a minimum.

    As for sea targets, they need to be picked up from moving waves that create a dopplershift too. A different case.

    P/s: jet engine isn't hot enough for the plasma effect.
    What about an active afterburner attached at its rear?

  15. #135
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    Skunk works has some new 6 gen renderings out. Hmm whats does that look like.




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    Ah yes.. those air-intakes over the LERX area again
    Thanks

  17. #137
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    Skunk works has some new 6 gen renderings out. Hmm whats does that look like.
    Yes ... but surely not like a T50 !
    IMO even a A320 and a B767 - YES 767 - have more in common than these two designs.
    ...

    He was my North, my South, my East and West,
    My working week and my Sunday rest,
    My noon, my midnight, my talk, my song;
    I thought that love would last forever; I was wrong.

    The stars are not wanted now; put out every one:
    Pack up the moon and dismantle the sun;
    Pour away the ocean and sweep up the woods:
    For nothing now can ever come to any good.
    -------------------------------------------------
    W.H.Auden (1945)

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    Quote Originally Posted by KGB View Post
    Skunk works has some new 6 gen renderings out. Hmm whats does that look like.



    It looks like an f-22? Impractical intake layout aside, the concept focuses on all aspect stealth with side surface angles akin to the yf-23.

    This is opposed to the T-50 example shown which focussed on affordable (poor man's) mediocre frontal stealth and minimal attention to side and rear aspect stealth.

    The Su-57's side aspect stealth is quite literally the worst of all of the world's stealth aircraft present, past, in testing and prototype phase, by a large margin too.
    Last edited by ActionJackson; 18th September 2017 at 22:50.

  19. #139
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    The "experts" aside, new pic:

    http://img818.imageshack.us/img818/9098/rsz11rsz3807.jpg

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    It looks like an f-22? Impractical intake layout aside, the concept focuses on all aspect stealth with side surface angles akin to the yf-23.

    This is opposed to the T-50 example shown which focussed on affordable (poor man's) mediocre frontal stealth and minimal attention to side and rear aspect stealth.

    The Su-57's side aspect stealth is quite literally the worst of all of the world's stealth aircraft present, past, in testing and prototype phase, by a large margin too.

    Last edited by ActionJackson; 18th September 2017 at 21:50.
    My sincere and utmost proffesional response to your post;

    https://youtu.be/oV-ZxSmlbjY


    Great picture TR1!!
    Last edited by haavarla; 19th September 2017 at 17:40.
    Thanks

  21. #141
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    wow, what a clean looking Pak-fa!
    love the new colors. not as much as the digi shark one but this is close

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    Quote Originally Posted by PeeD
    I have never said that the average RCS should be considered to judge stealth designs performance. Nor do I use the F-16 RCS plot you provided but that of the Sukharevsky's publication on RCS. I'm not even saying that the 0,3m claim from Russian side is true and I don't know what they meant exactly. In my previous post I pointed out the advantages of stealth with the F-22 as example. We have different views on the performance levels and tactical application but even Russians have developed a stealth design despite their 0,3m claim.In exercises and simulated engagements the rules of engagement/parameters can be defined as deemed appropriate, its not about conspiracy theory.
    Both, J-20 and F-22/-33 need to perform several magnitudes better than the Russian claim of 0,3m (unknown definition) to approach a high power radar of a AEW aircraft undetected (what range?).
    I go for one added magnitude due to RAM/RAS and you go for several magnitudes due to it.
    There are too many unknowns about the simulated engagements, about RAM/RAS performance and about non-simulated reality effects such as traveling waves etc.
    Never said anything else. But we differ on the performance level.
    I may have mistaken between you and Paralay.
    In my opinion, if you look at the simulated scattering charts of F-35, its shape will have RCS fluctuated between -10 to -30 dBsm in an arc of 40-60 frontal (+/-20-30 left/right), add in -10 to -15 dBsm reduction due to RAM, then another -5 to -10 dBsm reduction due to RAS, then you will see final RCS between -28 to -33 dBsm frontally is totally achieveable for stealth fighters in general. It will also explained the feat they achieved in exercrises and why they need luneberg lens
    There are rule of engagements in exercrises, no doubt, but they will try to simulate the exercrise as close to reality as they can. What ever tactics you can think of, iam sure it would have crossed their mind if it is useful.

    Quote Originally Posted by PeeD
    It translates into flanking. A F-35 detects the opponent first and tries to avoid his radar by approaching it inside his low RCS lobes. He more or less knows at what threshold the enemies radar would detect it, so he either kills it outside that envelope or fly/flanks it outside the opponents scan field. Anyway, yes stealth offers this tactical advantage.
    Iam trying to say tactics can go both ways. Tactic such as spread out formation can help but it is two-edged knife because you need to divide your force out very thin if you want to prepare against enemies coming from different directions


    Quote Originally Posted by PeeD
    Again its about the "how much", 2/3 reduction as your article claims or less in modern radars?
    I already mentioned array active sidelobe canceling etc. and there are more such as space-time adaptive processing. This is basically a hard and software problem, much less a physical one. Today there are enough solutions to avoid a 2/3 range performance collapse because the dopplershift of the fleeing target can't be measured good enough.
    This is a physical effect that indeed occurs in a very special and small region. The question is what dopplershift the ground radar can measure. If its high enough via techniques like STAP, the ability to tactically exploit it, decreases to a minimum.
    As for sea targets, they need to be picked up from moving waves that create a dopplershift too. A different case.
    It is not that doppler shift can't be measured good enough, the problem is the Doppler shift of target is the same as your side lobes reflection. There are modern techniques that help the detection of slowing moving targets or target with the same doppler shift as your side lobes. But even on the new AESA Zhuk-AE we see the significant different between head on and tail on targets.
    Sea targets are the exact same case, the reflection from targets has the same or a very slight different Doppler shift from the clutters, so they are much harder to detect. Just a reminder, ground reflection do create Doppler shift because your aircraft is moving. If you look at Irbis-E slide, the detection range from ground targets like tanks and surface to air missiles are also very short despite their massive RCS.


    Quote Originally Posted by PeeD
    What about an active afterburner attached at its rear?
    I don't think it is hot enough to provide the amount of plasma needed for RCS reduction. If it is rear view radar blocker unique nozzles wouldn't be needed for stealth aircraft
    Last edited by mig-31bm; 19th September 2017 at 06:01.

  23. #143
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    ^ Paralay is the Russian guy who likes to do fantasy art and mock ups, kind of like Topspeed

    PeeD is Iranian

  24. #144
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    @ Deino
    Yes ... but surely not like a T50 !
    Then you are blind. Its a pancake low profile design with a blended wing and the same small angled vertical stabilizers.

    Which is totally unlike the J 20 or F 22 or F 35.

  25. #145
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    Quote Originally Posted by "KGB"
    Then you are blind. Its a pancake low profile design with a blended wing and the same small angled vertical stabilizers.

    Which is totally unlike the J 20 or F 22 or F 35.
    They look nothing alike, the concept has no horizontal stabilators while Su-57/F-35/F-22 have 2. The render has side intakes whereas Su-57's intakes are under the body with a tunnel in middle. And beside, it is just a CGI rather than a real aircraft, why do you even care?

  26. #146
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    That ****ty CGI jet is a Delta design with two horizontal Stabs.
    Thanks

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    @actionjackson The Su-57's side aspect stealth is quite literally the worst of all of the world's stealth aircraft present, past, in testing and prototype phase, by a large margin too.
    Somehow if this was Japans stealth prototype, you wouldn't seem to be so interested in the "side aspect"

    How come the experts don't apply their expertise to all the other stealth entries ? Go to the other aircrafts pages and the same ppl are like "oh thats cool" "what kinda radar is it getting brah"

  28. #148
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    Quote Originally Posted by KGB View Post
    Somehow if this was Japans stealth prototype, you wouldn't seem to be so interested in the "side aspect"

    How come the experts don't apply their expertise to all the other stealth entries ? Go to the other aircrafts pages and the same ppl are like "oh thats cool" "what kinda radar is it getting brah"
    Other than the canopy itself (obviously reused from legacy aircraft and targeted for replacement) what's wrong with the Japanese fighter? Every side surface is consistently angled at least. No surfaces at a normal to incident beams coming from the ground 200km away like the Su has.

  29. #149
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    Here is a suggestion KGB, open a thread for "stealth" aircraft design and discussion. It will serve dual purpose:
    Those who come on here to read news/updates about the Su-57 won't get bombarded with endless rehashing of "Su-57 looks like the YF-23", RCS scatter plots made by undergrads in China, and constant arguments over the RCS shaping of the F-22, Su-57, et al.

    Those who may be interested in that can have a dedicated thread to discuss such issues, and those who aren't interested can steer clear.

    P.S. The posting of L-M fantasy drawings (which look nothing like the Su-57), is pointless and silly. Give the thread back to news and discussion about the the aircraft in the title of the thread.

  30. #150
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    FBW

    From time to time, some Pak Fa phobic posters feel the need to come on the Pak Fa thread and announce to the world that the Pak is not stealth. When that happens, they will have to get set straight and the thread will heat up a bit.

    Then after that, the thread will go cold. Just the way you seem to like it. You'll have to look for it on page 2 or 3.

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