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Airman 1st Class
- 121
- Jul 13, 2020
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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?)
Evidence suggests that only a small quantity of PAK FAs will enter Russian service this decade—too few to alter the balance of airpower in the near term.nationalinterest.org
Would this translate to Turkey shoot in an actual war?
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.
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.
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?)
Evidence suggests that only a small quantity of PAK FAs will enter Russian service this decade—too few to alter the balance of airpower in the near term.nationalinterest.org
Would this translate to Turkey shoot in an actual war?
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.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!
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.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
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.
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.
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.
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.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.
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.
Just so.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.
They do, yes.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?