F-22 hundred of times more stealthy than Su-57?

[Nodeo-Franvier]

According to this article F-22 radar cross section is less than 1% of Su-57.

Stealth Fighter Showdown: Russia's Su-57 vs. the F-22 Raptor (Who Wins?)

Here’s What You Need to Remember: Step right up, ladies and gentlemen! Entering the ring today are the two ultimate stealth fighters of the day, the F-22 Raptor and the PAK FA T-50 or what we now call the Su-57. The former has already completed its production run (or has it?), the latter will...

nationalinterest.org

Would this translate to Turkey shoot in an actual war?

 

[ODonovan]

From what I've read, F-35s are going to be used as "spotters," sneaking into enemy airspace and "painting" (designating) targets for F-22s as well as for long range air to air "missile boats" such as F-15s and even B-52s. Since the Su-57 is NOT stealthy at all, except from the front, having an F-35 abreast of it or behind it would negate most of its stealth. We're going to be getting the F-15EX Eagle II pretty soon, which can carry a sh*t ton of air to air missiles. I don't even want to guess how many the B-52 can carry. So, should any hostilities occur, IF things go as planned, I would expect it soon to be raining Russian aircraft parts and for there to be a LOT of screaming and cursing in Russian. IF things go as planned...


-Irish

 

[Token]

According to this article F-22 radar cross section is less than 1% of Su-57.

Stealth Fighter Showdown: Russia's Su-57 vs. the F-22 Raptor (Who Wins?)

Here’s What You Need to Remember: Step right up, ladies and gentlemen! Entering the ring today are the two ultimate stealth fighters of the day, the F-22 Raptor and the PAK FA T-50 or what we now call the Su-57. The former has already completed its production run (or has it?), the latter will...

nationalinterest.org

Would this translate to Turkey shoot in an actual war?

"Stealth" is always a relative term.

Looking at the Su-57 I see exposed rivet heads, I see what is probably a very reflective canopy bow and frame, I see straight and square panel edges, things like that. To me it looks like a design that was optimized for air superiority and the RCS was also reduced on specific aspect angles. For sure those thrust vector nozzles are purely performance designed, with no real nod given to RCS reduction.

I suspect that on the nose the RCS will be reduced significantly, and to beam and aft very much less well controlled.

Yes, I have no trouble at all believing the F-22 has an average RCS 20 dBsm, or more, below that of the Su-57 as it has been demonstrated. That does not seem a stretch to me at all.

As for who wins, first to see, first to kill. Overall I suspect that the Su-57 is at a disadvantage to both the F-22 and the F-35, although if you can get them into its fight, say in the phone booth, the Su-57 looks VERY capable. And the off-axis, high angle, queuing and launch will be tough to beat.

T!

 

[swampyankee]

Everybody's military observables are highly classified, at least by the US. Any US defense contractor which did an RCS analysis of something a bit incredibly non-exotic like, oh, the T-41 (a Cessna 172 with USAF markings), that analysis would get a "SECRET" stamp put on it.

Anyone who has reliable observables data on the Su-57, F-22, or F-35 isn't talking, either out of taking their vow of secrecy seriously or to avoid spending a very long time in a very small room which locks from the outside.

 

[Token]

Everybody's military observables are highly classified, at least by the US. Any US defense contractor which did an RCS analysis of something a bit incredibly non-exotic like, oh, the T-41 (a Cessna 172 with USAF markings), that analysis would get a "SECRET" stamp put on it.

Anyone who has reliable observables data on the Su-57, F-22, or F-35 isn't talking, either out of taking their vow of secrecy seriously or to avoid spending a very long time in a very small room which locks from the outside.

That is certainly true for actual RCS range measured data or intelligence assessments. However, shape analysis and an understanding of surface scatter and surface conduction modeling can get you in the ball park. There is a LOT of unclassified modeling and simulation out there to pull from. There is a lot of unclassified research work to pull from. And there are past examples that have been measured. There is a lot of unclassified information on paints, coatings and surface materials out there. It is possible to make some educated guesses.

As for "classified", the surface materials may be possible to protect from general knowledge, but the shapes are not. If you release a picture of it people can start to make educated, sometimes very close (in general terms), guesses. The interesting part there becomes surface materials and underlying shapes. You might be able to model surface shapes, but what if the surface is RF transparent (or absorptive), and the specifically shaped reflective surface is under the visible surface?

In your example, a hypothetical RCS analysis of a T-41, involving actual RCS range measurements, probably having a secret marking, that is possibly, probably even, correct. But, a person could do an unclassified analysis and measurement of a C-172 just fine, and it would not end up with such a classification marking on it...unless you did it on the DoD dime, in which case it still might end up classified.

The take away is that while it might be probable that anyone claiming to know the exact RCS's of various modern, front line, military aircraft, is either violating their security agreements or lying, if you have the right education or experience it is also very possible to make educated guesses that are not in the realm of the classified. RCS modeling and management is not rocket surgery, it is math and research.

T!

 

[pbehn]

I havn't seen any definition of "stealthy", in most branches of the military being 100 times stronger means you have 100 times more of something. In stealth, with waves being reflected, one "hundred times" may or may not be a big deal.

 

[Token]

I havn't seen any definition of "stealthy", in most branches of the military being 100 times stronger means you have 100 times more of something. In stealth, with waves being reflected, one "hundred times" may or may not be a big deal.

To the best of my knowledge there is no one numeric definition of "stealth", it is simply the result of intentionally reducing, by design, an objects detection signature. And although people tend to fixate on Radar Cross Section (RCS) reduction, stealth also includes other signature reduction, sound, IR, visual, etc

OK, lets put it in real world application. You will see that "one hundred times" is a big deal. I am not going to clutter things up with math, but if you want to do the calculations yourself you can use either the free space loss equation or the radar range equation.

Aircraft A has a forward aspect RCS of 0 dBsm, that is the equivalent of a target RCS of 1 square meter. Note that this is RCS, and not physical size, don't let the "square meter" thing twist you into physical size comparisons. Aircraft B is physically the same size but has a forward aspect RCS that is 1/100 of aircraft A, or an RCS of 0.01 square meters, this is expressed as -20 dBsm.

If both targets are head on and a given radar can just barely detect and track Aircraft A (the larger RCS target) at 100 km range, it will not be able to see and track Aircraft B (the 1/100 RCS target) until it is at 10 km.

The real world difference between the aircraft, one with 1/100 the RCS of the other, or a 20 dBsm difference in RCS, is that one (the larger RCS target) can be tracked, under identical conditions, 10 times as far away as the other.

That is a pretty significant difference.

T!

 

[ARTESH]

According to this article F-22 radar cross section is less than 1% of Su-57.

Stealth Fighter Showdown: Russia's Su-57 vs. the F-22 Raptor (Who Wins?)

Here’s What You Need to Remember: Step right up, ladies and gentlemen! Entering the ring today are the two ultimate stealth fighters of the day, the F-22 Raptor and the PAK FA T-50 or what we now call the Su-57. The former has already completed its production run (or has it?), the latter will...

nationalinterest.org

Would this translate to Turkey shoot in an actual war?

living in Iran, learnt that not anything written in "Sites or Books" are trustworthy! Specially News Agencies! one big reason is propaganda! the other big one, would be politics!

 

[pbehn]

To the best of my knowledge there is no one numeric definition of "stealth", it is simply the result of intentionally reducing, by design, an objects detection signature. And although people tend to fixate on Radar Cross Section (RCS) reduction, stealth also includes other signature reduction, sound, IR, visual, etc

OK, lets put it in real world application. You will see that "one hundred times" is a big deal. I am not going to clutter things up with math, but if you want to do the calculations yourself you can use either the free space loss equation or the radar range equation.

Aircraft A has a forward aspect RCS of 0 dBsm, that is the equivalent of a target RCS of 1 square meter. Note that this is RCS, and not physical size, don't let the "square meter" thing twist you into physical size comparisons. Aircraft B is physically the same size but has a forward aspect RCS that is 1/100 of aircraft A, or an RCS of 0.01 square meters, this is expressed as -20 dBsm.

If both targets are head on and a given radar can just barely detect and track Aircraft A (the larger RCS target) at 100 km range, it will not be able to see and track Aircraft B (the 1/100 RCS target) until it is at 10 km.

The real world difference between the aircraft, one with 1/100 the RCS of the other, or a 20 dBsm difference in RCS, is that one (the larger RCS target) can be tracked, under identical conditions, 10 times as far away as the other.

That is a pretty significant difference.

T!

The thing is, I was a UT technician and discussion of 20dBisms and 5 dB isms dont phase me. What is your actual point. A drop of 20dB is a 90% drop in signal strength, which is why factors of "100 times" are misleading.


I was taught ultrasonics by C.J. Abrahams who pioneered the 20 dB drop sizing technique with MAPs. Signal response is entirely due to orientation, the difference between maximum and minimum response with a planar reflector is massively more than 100 times and attenuation, filtering frequency also have effects that are over 100 times.


If you could quote the energy of the transmitted signal and the energy of the received signal that would possibly show why "100 times" may not be any sort of deal at all. Like the possibility of me living to 125 being 100 times less than living to 124.

 

[FLYBOYJ]

From what I've read, F-35s are going to be used as "spotters," sneaking into enemy airspace and "painting" (designating) targets for F-22s as well as for long range air to air "missile boats" such as F-15s and even B-52s. Since the Su-57 is NOT stealthy at all, except from the front, having an F-35 abreast of it or behind it would negate most of its stealth. We're going to be getting the F-15EX Eagle II pretty soon, which can carry a sh*t ton of air to air missiles. I don't even want to guess how many the B-52 can carry. So, should any hostilities occur, IF things go as planned, I would expect it soon to be raining Russian aircraft parts and for there to be a LOT of screaming and cursing in Russian. IF things go as planned...


-Irish

I don't know where you "read" this, but the F-35 and F-15EX are STRIKE aircraft - in layman's terms, they are bombers. The F-22 is a dedicated air-to-air fighter. The F-35 (and I'm talking F-35A) is basically a flying supercomputer that can fulfill several functions to include battlefield integration and AEW roles. The F-15EX carries "the bombs" but also has an outstanding air-to-air capability.

 

[Token]

The thing is, I was a UT technician and discussion of 20dBisms and 5 dB isms dont phase me. What is your actual point. A drop of 20dB is a 90% drop in signal strength, which is why factors of "100 times" are misleading.

Not sure what you are trying to say here. The actual point, the most important point, of a 20 dB reduction (1/100) in RCS is that the 20 dBsm larger target can be tracked by radar, under identical conditions, 10 times as far away as the 20 dBsm smaller RCS target. That 10 times range relationship is the real number for a 1/100, or 20 dBsm reduced, RCS.

If, using a specific radar under specific conditions, the larger RCS target can just be tracked (maximum detection range for that radar with that target under those conditions) at or inside 100 km, then the smaller RCS target, 1/100 RCS, cannot be tracked, with that radar and under those conditions, until the aircraft is at or inside 10 km.

Every radar design has a specific maximum range at which it can track a given size (size in RCS, not physical size) target. That range is determined by many factors, things like the transmitted power, the antenna gain, the receiver sensitivity, etc, and one of these factors is the reflectivity of the target. We are defining that reflectivity when we define the RCS of the target.

In the radar world, a drop of 20 dB is not a 90% drop in signal strength. It is a 99% drop in signal strength, or 1/100 the signal. A 90% drop in signal strength would be 10 dB reduction, or 1/10.

I was taught ultrasonics by C.J. Abrahams who pioneered the 20 dB drop sizing technique with MAPs. Signal response is entirely due to orientation, the difference between maximum and minimum response with a planar reflector is massively more than 100 times and attenuation, filtering frequency also have effects that are over 100 times.


If you could quote the energy of the transmitted signal and the energy of the received signal that would possibly show why "100 times" may not be any sort of deal at all. Like the possibility of me living to 125 being 100 times less than living to 124.

Hmmm... I am still not getting the question. Are you asking for this function as a probability of detection (PD)? If so you have to express that with a range also.

The maximum detection range, for a specific radar and with a given PD, is what changes with RCS changes.

Also, RCS cannot be expressed without also considering orientation. A target that is +2 dBsm in a nose on aspect may be +20 dBsm when viewed from abeam. But comparisons are typically done with equal aspects, i.e. aircraft A is 20 dBsm larger RCS head on than aircraft B is head on.

T!

 

[swampyankee]

That is certainly true for actual RCS range measured data or intelligence assessments. However, shape analysis and an understanding of surface scatter and surface conduction modeling can get you in the ball park. There is a LOT of unclassified modeling and simulation out there to pull from. There is a lot of unclassified research work to pull from. And there are past examples that have been measured. There is a lot of unclassified information on paints, coatings and surface materials out there. It is possible to make some educated guesses.

As for "classified", the surface materials may be possible to protect from general knowledge, but the shapes are not. If you release a picture of it people can start to make educated, sometimes very close (in general terms), guesses. The interesting part there becomes surface materials and underlying shapes. You might be able to model surface shapes, but what if the surface is RF transparent (or absorptive), and the specifically shaped reflective surface is under the visible surface?

In your example, a hypothetical RCS analysis of a T-41, involving actual RCS range measurements, probably having a secret marking, that is possibly, probably even, correct. But, a person could do an unclassified analysis and measurement of a C-172 just fine, and it would not end up with such a classification marking on it...unless you did it on the DoD dime, in which case it still might end up classified.

The take away is that while it might be probable that anyone claiming to know the exact RCS's of various modern, front line, military aircraft, is either violating their security agreements or lying, if you have the right education or experience it is also very possible to make educated guesses that are not in the realm of the classified. RCS modeling and management is not rocket surgery, it is math and research.

T!

Reasonably accurate RCS modelling takes a fairly hefty computer, albeit not a supercomputer, and a good surface model, certainly much better than one can get from conventional photography.

Quite a lot of the papers about RCS modeling that I got a chance to read when I was working in the field were translated from Russian, so it's certain that the physics are universally known (at least among the cognescenti, a group to which I most definitely do not belong -- it's been nearly 40 years since I had anything to do with RCS). Quite a lot of stealth is in pretty small details, which is one reason why the B-2 was insanely expensive to keep fully stealthed (for one, I've read the RAM coating was quickly degraded by rain), and a reason why fit-and-finish is very important to producing stealth.

I suspect the Su-57 has a significantly larger cross section than the F-22 from tactically significant viewpoints, but I'd not put much of my money on it. On the other hand, I also suspect that the Su-57 has a superior RCS to the F-15, F-16, or F-18 (any model). I'd not bet much on that, either.

 

[Token]

Reasonably accurate RCS modelling takes a fairly hefty computer, albeit not a supercomputer, and a good surface model, certainly much better than one can get from conventional photography.

Sure, accuracy requires more detail, but starting estimates are possible (and done reasonably often) from things like imagery. Looking at things like the canopy construction and the access panel designs will tell you they did not put the effort into the details that the F-22 and F-35 have.

I suspect the Su-57 has a significantly larger cross section than the F-22 from tactically significant viewpoints, but I'd not put much of my money on it. On the other hand, I also suspect that the Su-57 has a superior RCS to the F-15, F-16, or F-18 (any model). I'd not bet much on that, either.

It depends on what you want to call a "significantly larger cross section" vs F-22. I would put a fair amount on there being a "significant" difference, I feel it is a safe bet. I consider things like 6 or 10 dB significant, that does equate to a real, and usable, detection range advantage. I would not bet a large sum on "1/100" though...unless you gave me good odds

T!

 

[Glider]

This article was written some time ago, not the phrase
However, the United States finally deployed its own equivalent of the R-73, the AIM-9X, in 2004, and F-22s are finally planned to have the capability to use AIM-9Xs by 2017. Helmet-mounted sights should come in 2020

Lets look at what has happened to the Su57.
a) In 2018 India who had invested a lot into this programme walked away from it because it didn't believe that it met their requirements for stealth, combat avionics, radars and sensors. This is s serious problem for India as Pakistan its long term potential enemy is close to China who has its own program of this nature and the tensions between India and China are also ramping up.

b) Russia advised that the first two aircraft were to be delivered in 2019 its barely in service and with any complex aircraft there are going to be teething problems.

c) I don't think it has won any contract for sales.

d) If it was advanced as the Russians say they would never export it to a country where the USA could get a look at it.

This is compared to the F22 an aircraft that has been designed, built, honed and finished production. Should the USA start developing a replacement for the F22 they have a raft of experience to build on.

Personally I don't think the Su57 is even close to the F22 or F35

 

[pbehn]

Not sure what you are trying to say here. The actual point, the most important point, of a 20 dB reduction (1/100) in RCS is that the 20 dBsm larger target can be tracked by radar, under identical conditions, 10 times as far away as the 20 dBsm smaller RCS target. That 10 times range relationship is the real number for a 1/100, or 20 dBsm reduced, RCS.

If, using a specific radar under specific conditions, the larger RCS target can just be tracked (maximum detection range for that radar with that target under those conditions) at or inside 100 km, then the smaller RCS target, 1/100 RCS, cannot be tracked, with that radar and under those conditions, until the aircraft is at or inside 10 km.

Every radar design has a specific maximum range at which it can track a given size (size in RCS, not physical size) target. That range is determined by many factors, things like the transmitted power, the antenna gain, the receiver sensitivity, etc, and one of these factors is the reflectivity of the target. We are defining that reflectivity when we define the RCS of the target.

In the radar world, a drop of 20 dB is not a 90% drop in signal strength. It is a 99% drop in signal strength, or 1/100 the signal. A 90% drop in signal strength would be 10 dB reduction, or 1/10.



Hmmm... I am still not getting the question. Are you asking for this function as a probability of detection (PD)? If so you have to express that with a range also.

The maximum detection range, for a specific radar and with a given PD, is what changes with RCS changes.

Also, RCS cannot be expressed without also considering orientation. A target that is +2 dBsm in a nose on aspect may be +20 dBsm when viewed from abeam. But comparisons are typically done with equal aspects, i.e. aircraft A is 20 dBsm larger RCS head on than aircraft B is head on.

T!

I was just discussing what "100 times" means. The differences are so huge that one hundred times may or may not mean anything. I just looked up the decibel and in power terms 20dB is 100, and in amplitude terms it is 10. My point was simply stating something is "one hundred times" more or less may or may not be important. Something 100 times bigger or heavier than a hydrogen atom still isnt big. If the sun is 100 times hotter or cooler it is still hot. The technicalities of your post are what the simple statement of "100 times more stealthy" dont address. It maybe that at a range of 100 miles the Su 57 returns 100 times more from a radar than an F22 does but is that important? Probability of detection is the only thing that matters, and the only way I can see that one is 100 times greater than the other is if they are both fantastically small, like the probability of being hit by an individual shell in a B-17 at 25,000ft.

Decibel - Wikipedia

en.wikipedia.org

 

[Token]

I was just discussing what "100 times" means. The differences are so huge that one hundred times may or may not mean anything. I just looked up the decibel and in power terms 20dB is 100, and in amplitude terms it is 10. My point was simply stating something is "one hundred times" more or less may or may not be important. Something 100 times bigger or heavier than a hydrogen atom still isnt big. If the sun is 100 times hotter or cooler it is still hot. The technicalities of your post are what the simple statement of "100 times more stealthy" dont address. It maybe that at a range of 100 miles the Su 57 returns 100 times more from a radar than an F22 does but is that important? Probability of detection is the only thing that matters, and the only way I can see that one is 100 times greater than the other is if they are both fantastically small, like the probability of being hit by an individual shell in a B-17 at 25,000ft.

The technicalities in my post are exactly what "100 times more stealthy" means. By the way, "100 times" was introduced by the OP of this thread, not by the writers of the article in question. I don't think the article says anything like that, it uses real definitions of RCS in square meters. At all ranges (assuming the information is correct), not just a specific range, the ratio will remain the same. At 100 miles the Su-57 returns 100 times more radar energy, and at 5 miles the Su-57 returns 100 times as much radar energy. The total energy may be different, but the ratios of energy will not be.

Lets look at what the article says. It says the F-22 is believed to have an RCS of 0.0001 sm and that the Su-57 is claimed to have an RCS of 0.1 sm from the front aspect, and something less than 1 sm for all aspect. The RCS numbers used for the F-22 come from an Air Power Australia (APA) publication done several years ago, in general that source tends to be pretty good, but they are working in the unclassified realm, so there is no guarantee their numbers are correct. By the way, their guestimate on the front aspect of the Su-57 (or at least the PAK FA it derived from) is more along the lines of 0.01 sm in front aspect. The source for the Su-57 numbers in the National Interest article appears to be a combination of the APA paper and the patent papers associated with the Su-57.

You can see there is an order of magnitude error someplace in all of that, I don't know if that is a missed decimal point by either the National Interest article or the APA article. Since the National Interest article points to the APA paper as its source, I am assuming the "0.1 sm" used in the National Interest is the typo, and they really meant the "0.01 sm" in the original source. And, 0.01 sm is 100 times as large as 0.0001 sm

But the gist of it is that "100 times more stealthy" is generally taken to mean that one target has an RCS of 1/100 the other target. Or an RCS difference of 20 dB between the two, one target exhibits an RCS 20 dBsm larger than the other target, whatever the starting value is. If target A is said to be -30 dBsm (0.0001 sm) and target B is 20 dBsm larger (100 times larger expressed in square meters RCS), that means target B is -10 dBsm (0.01 sm).

Why this is important is what I addressed. The target that is 20 dBsm larger will always be able to be detected by radar at a longer maximum range under the same conditions, with the same probability of detection, simply by virtue of its larger RCS.

Using the radar range equation you can calculate the maximum distance a given radar (if you know all of its parameters) can possibly track a given size target. Part of the radar range equation does consider a probability of detection, generally a number of 80% or greater is used. Typically this range performance is quoted as the range to track a 0 dBsm (1.0 sq meter) target, but you can also calculate it for any other size, such as -10 dBsm or -30 dBsm.

Use a known radar example, say the FAA ASR-11 primary track radar. This radar has a specification of being able to track a 0 dBsm target, a 1 square meter RCS target, at 55 nm, or 102 km (Table 3.4-1, page 16, here http://www.tc.faa.gov/its/worldpac/techrpt/cttn9727.pdf ). At 102 km, or less, this radar has a greater than 80% probability of tracking a target with an RCS of 0 dBsm. It does not have the same probability of detection for a -10 dBsm target until the target gets within 32 km, and it will not have that same probability of detection with a -30 dBsm target until the target is within 3.2 km.

Using the real world, known, ASR-11 radar, and assuming the RCS numbers quoted in the Ausie Air Power paper are correct, we can calculate that the ASR-11 radar would not detect (with the standard 80% PD) the inbound (front aspect) Su-57 until the aircraft was inside 32 km, and it would not detect the inbound (front aspect) F-22 until the aircraft was inside 3.2 km.

Other radars will have similar tracking range disparities between the two aircraft. The exact tracking ranges will be different, but the ratio of detection ranges will remain similarly skewed. If the numbers presented in either article are correct, the Su-57 can be seen by radar 10 times as far away as the F-22 can, and I have given a real world radar example using those numbers.

That seems significant to me.

T!

 

[Thumpalumpacus]

I was just discussing what "100 times" means. The differences are so huge that one hundred times may or may not mean anything. I just looked up the decibel and in power terms 20dB is 100, and in amplitude terms it is 10.

In trying to follow this conversation, when I see the term "dB" I'm thinking, as a musician, that radar -- and detection -- work on a logarithmic scale as well?

 

[swampyankee]

In trying to follow this conversation, when I see the term "dB" I'm thinking, as a musician, that radar -- and detection -- work on a logarithmic scale as well?

Just so.

 

[Thumpalumpacus]

Just so.

Thank you, that helps me.

 

[GrauGeist]

In trying to follow this conversation, when I see the term "dB" I'm thinking, as a musician, that radar -- and detection -- work on a logarithmic scale as well?

They do, yes.

Of course, without a receiver/amplifier, the frequencies cannot be heard by the human ear, but they follow the same logic. Like that hum you get in your electric guitar is 60Hz, just out of human hearing range, but with an amp, becomes audible (I think around the B scale?).

The human hearing range is roughly 20Hz to 20kHz, most radar freqs operate in the high gigahertz range (like up to 36gHz).

But all can be justified with decibel logorithyms.

I am far from a math whiz, but hopefully this helps a little...