You should travel to Florida I heard that there were like 17 F-22s damaged or destroyed in a hurricane so if the air force has no use for them you can always ask.
Who knows whether the F-22 will permanently return to Tyndall AFB, but the Raptor will be coming back periodically to get its stealth coating fixed up.
www.airforcetimes.com
“Some of them got more damaged than others, but they all flew out of here, so I think that’s pretty incredible that that happened,” he said. “Some of them will take a little longer to repair to get back to full capability, but some of them that were left behind are back in our lineup flying every day.”
I disagree. Any person can educate themselves by studying the underlying physics at work and perform the *same* "military grade research". "Military researchers" do no have access to some secret physics knowledge.
For instance, you can have RAM, or you can have setups for destructive interference at a given wavelength of interest, without knowing the depth and characteristics of the RAM you are not going to be accurate.
Well, I assume such simulation is going to be reasonable to assess the basic geometry of a plane, but to analyse real world complexity, or when people are discussing abut RCS of 0.0001 sqm for a house-sized plane, this kind of simplified approach is not accurate enough.
The "basic geometry of a plane" is what determines almost all of the RCS. You can reflect far more energy than you could possibly absorb. That was the real innovation of the XST studies.
There are many free and commercial software packages (and services) for RCS prediction. POFACETS is just one, though one that is very easy to access. It is used by many universities and defense contractors performing "military grade research". There are certainly others that can do things that POFACETS does not do.
It is certainly more "accurate" than pasting "RCS" numbers found on the internet to compare two aircraft!
But to get back on topic, someone has already done public RCS prediction of the T-50 for you:
APA Analysis Paper APA-2012-03; Title: A Preliminary Assessment of Specular Radar Cross Section Performance in the Chengdu J-20 Prototype; Abstract: This study has explored the specular Radar Cross Section of the Sukhoi T-50 prototype aircraft shaping design. Simulations using a Physical Optics...
The "basic geometry of a plane" is what determines almost all of the RCS. You can reflect far more energy than you could possibly absorb. That was the real innovation of the XST studies.
There are many free and commercial software packages (and services) for RCS prediction. POFACETS is just one, though one that is very easy to access. It is used by many universities and defense contractors performing "military grade research". There are certainly others that can do things that POFACETS does not do.
It is certainly more "accurate" than pasting "RCS" numbers found on the internet to compare two aircraft!
But to get back on topic, someone has already done public RCS prediction of the T-50 for you:
I think it depends on who does the public RCS prediction, such as you brought up POFACETS while others that have used such a software gave mean frontal RCS of F-35 model as -11dBsm and that there were a couple of higher RCS peaks in the aircrafts frontal arc. I have heard people tell me in the past that Aus Power has like some bias with the F-35, but not with the F-22(is that correct?) there might be a chance LMFS might dismiss it for reference purposes if he comes back online anyways because I assume he does not trust how aus airpower is more favorable of one US aircraft over the other, than he will have doubts Russian aircrafts based on aus air power's RCS analysis would be any better.
Not realistic !!!!!
You are constantly forgetting about the beam width.
Under your conditions for the x-band, the beam width is 0.3 degrees. It takes 34,000 steps to scan a 60 * 60 sector. Modern radars scan this sector in about 10 s with a range of 150 km on average. The full view for the APG-81 is 19 seconds at a distance of 160 km. This is approximately 0.02 seconds per step. 34,000 * 0.02 = 654 s or 10 minutes.
Yes, but I would not like to be the operator of such a radar station, in a combat situation, which scans the 60 * 60 sector in 10 minutes.
That is a weak excuse consider that I'm comparing the detection range, not the scan time. The big reason VHF is often claimed as anti stealth is the much better detection range against stealth aircraft. But if what you said about RCS is correct, then VHF will have inferior detection range compared to X-bank X band radar:
Dimension: 2*2 meter -> Area: 4 m2 VHF band radar:
Dimension: 20*4 meter -> Area: 80 m2
This time I added Rmax row for illustration so tell me, how can they get superior range from VHF radar?
These are the recommendations of the ITU. The International Telecommunication Union (ITU) is the United Nations specialized agency for information and communication technologies – ICTs.
Firstly, the chart I gave you came from IEEE
Secondly, I don't have to argue with ITU, you should open a book and learn the different between free space basic transmission loss and atmospheric attenuation.
Free space basic transmission loss has nothing to do with atmospheric attenuation, the free space path loss come from the spread out of signal, also known as the inverse square law
Thirdly, your equation is for isotropic antenna. Meaning it radiate in all direction
The comparison by Robert Wallace, the senior flight operation for F-35 and former chief of low observability for the B-2 is official, the chart given by Wu Jian Qi, the chief engineer of LC-8B, JY-27A manufacturer is official, the chart given by Lockheed Martin is also official .
This is a monograph by an Air Force major who refers to some other writer. I never found the original source. But the author writes everything about everything.
Also, are you not confused by the B-2 figure? In all sources that give a low RCS level - This figure is much less.
The RCS of a stealth aircraft is typically multiple orders of magnitude lower than a conventional plane and is often comparable to that of a small bird or large insect. "From the front, the F/A-22's signature is -40dBm2 (the size of a marble) while the F-35's is -30 dBm2 (the size of a golf ball). The F-35 is said to have a small area of vulnerability from the rear because engineers reduced cost by not designing a radar blocker for the engine exhaust." [Aviation Week & Space Technology; 11/14/2005, page 27] The F-35 stealthiness is a bit better than the B-2 bomber, which, in turn, was twice as good as that on the even older F-117. B-2 stealth bomber has a very small cross section. The RCS of a B-26 bomber exceeds 35 dBm2 (3100m2 ) from certain angles. In contrast, the RCS of the B-2 stealth bomber is widely reported to be about -40dBm2 .
I thought you only believe official source?. For me it is more believable that at some frequency B-2 has bigger RCS than F-117 than to believe Eurofighter and F-16 pretty much have the same RCS as F-22 and F-35
Впервые для печати: как сербам удалось сбить американский самолет-невидимку
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Yes, I admit that he could be wrong, but by + -10 degrees.
Otherwise, he would simply say that the rocket came from the right.
But there are no peaks in the 40-60 sector either.
There is quite a big peak at around 65 degrees. Nevertheless, it quite an impossible task to ask someone to make an accurate angle estimation with his eye when is literally being attacked by a missile the size of a telephone pole coming at him through the cloud cover. So +- 15 or even 20 degree inaccurate is understandable
The "basic geometry of a plane" is what determines almost all of the RCS. You can reflect far more energy than you could possibly absorb. That was the real innovation of the XST studies.
There are many free and commercial software packages (and services) for RCS prediction. POFACETS is just one, though one that is very easy to access. It is used by many universities and defense contractors performing "military grade research". There are certainly others that can do things that POFACETS does not do.
It is certainly more "accurate" than pasting "RCS" numbers found on the internet to compare two aircraft!
But to get back on topic, someone has already done public RCS prediction of the T-50 for you:
I think it depends on who does the public RCS prediction, such as you brought up POFACETS while others that have used such a software gave mean frontal RCS of F-35 model as -11dBsm and that there were a couple of higher RCS peaks in the aircrafts frontal arc. I have heard people tell me in the past that Aus Power has like some bias with the F-35, but not with the F-22(is that correct?) there might be a chance LMFS might dismiss it for reference purposes if he comes back online anyways because I assume he does not trust how aus airpower is more favorable of one US aircraft over the other, than he will have doubts Russian aircrafts based on aus air power's RCS analysis would be any better.
Small note: in that study, the F-35 model used for RCS simulation is the one without radome nose cone and canopy (they are assumed to be transparent to radar wave).
studies where radome nose cone and canopy is model look like this
They can distinguish helicopter, but not aircraft. Secondly, distinguish 2 helicopter at 2 locations is quite different from distinguish them while they are both inside the cell
I disagree. Any person can educate themselves by studying the underlying physics at work and perform the *same* "military grade research". "Military researchers" do no have access to some secret physics knowledge.
Yes of course, this is an old known simulation, also based on PO, but still they say the following interesting things:
In conclusion, this study has established through Physical Optics simulation across nine frequency bands, that no fundamental obstacles exist in the shaping design of the T-50 prototype, which might preclude its development into a genuine Very Low Observable design with constrained angular coverage.
... The latter underscores, as was the case with previous effort on the J-20 prototype, the difficulty in attempting to perform highly accurate numerical RCS modelling of foreign airframe designs, where access to high fidelity shaping data, surface feature data, and materials type and application is actively denied.
... Importantly, if the results of the Physical Optics specular return modelling yield RCS values from key aspects, at key frequencies, which are consistent with stated VLO performance values in US designs, to an order of magnitude, it is reasonable to conclude that a mature T-50 design will qualify as a genuine VLO design.
So APA sees no problem with the VLO of the Su-57 in the frontal arc (basically the same limitation F-35 has), but let me remind you that the internet "experts" all decided that APA is a totally discredited because they were critical with the F-35, and also because they were very appreciative of the PAK-FA.
You are right, it is all disinformation. The F-22 is -60 dBsm in reality, so it can place some -40 dBsm sources on the fuselage and still be VLO while faking its real RCS. BTW, the same happens with PAK-FA, for which all the prototypes shown until now are just to fool the West, maskirovka!!
I told you at the beginning that radars are compromises. And no one needs a radar with good range parameters, but at the same time with poor scanning properties.
Anyway, I don't want to be a radar operator that scans a small sector 60 * 60 in 1 minute 15 seconds.
As I said, this sector should be scanned in 10, maximum 15 seconds.
Secondly, I don't have to argue with ITU, you should open a book and learn the different between free space basic transmission loss and atmospheric attenuation.
The comparison by Robert Wallace, the senior flight operation for F-35 and former chief of low observability for the B-2 is official, the chart given by Wu Jian Qi, the chief engineer of LC-8B, JY-27A manufacturer is official, the chart given by Lockheed Martin is also official .
I thought you only believe official source?. For me it is more believable that at some frequency B-2 has bigger RCS than F-117 than to believe Eurofighter and F-16 pretty much have the same RCS as F-22 and F-35
There is quite a big peak at around 65 degrees. Nevertheless, it quite an impossible task to ask someone to make an accurate angle estimation with his eye when is literally being attacked by a missile the size of a telephone pole coming at him through the cloud cover. So +- 15 or even 20 degree inaccurate is understandable
First, you got the sides mixed up.
Second, don't think that the US Air Force pilots are topographic critins. The cockpit is full of landmarks to determine the angle.
Thirdly, if you imagine the flight of the F-117 relative to the radar, you will understand that 50 degrees is the maximum at the end of the trajectory. The detection took place at a lower angle.
But let me remind you that the internet "experts" all decided that APA is a totally discredited because they were critical with the F-35, and also because they were very appreciative of the PAK-FA.
APA was originally a very decent source, until their proposal of F-111 upgrade + F-22 plan get denied and replaced by F-35. After that point, all their analysis become quite trash because it always ended up the same way with everything from the East will destroy the F-35 just by existing and F-22 and F-111 is the solution for every problem. PAK-FA is just 1 of many things that they used as supposed F-35 destroyer
You are right, it is all disinformation. The F-22 is -60 dBsm in reality, so it can place some -40 dBsm sources on the fuselage and still be VLO while faking its real RCS. BTW, the same happens with PAK-FA, for which all the prototypes shown until now are just to fool the West, maskirovka!!
I don't think F-22 is -60 dBsm, and I certainly don't think it is -40 dBsm with the luneburg lens. The lens is also used so that air traffic radar can see them
That's interesting. I have not read that paper, but back in 2010(?) a forum member did basically that for the J-20 around the time of its first flight. Generated a model from photographs and predicted the RCS as part of a discussion thread here on the forum.
I have heard people tell me in the past that Aus Power has like some bias with the F-35, but not with the F-22(is that correct?) there might be a chance LMFS might dismiss it for reference purposes if he comes back online anyways because I assume he does not trust how aus airpower is more favorable of one US aircraft over the other, than he will have doubts Russian aircrafts based on aus air power's RCS analysis would be any better.
So the assumption is that the RCS prediction was somehow tampered with?
Anyone can attempt to reproduce those results by using the same tools to predict the RCS. Again, I encourage those participating in this thread to do so. They will learn quite a bit in the process.
That statement reinforces just about every point I have made in this thread. I again encourage those participating in the thread to learn about the underlying science.
Models studied at the Central Scientific Research Institute of the Aerospace Forces of the Ministry of Defense of the Russian Federation (NII VVKO). Former name "2nd Scientific Research Institute of the Ministry of Defense"
This is how full-size models are suspended on a rotating platform.
And irradiated in different wavelength bands
I mean, any computer simulation does not give high-quality results.
I told you at the beginning that radars are compromises. And no one needs a radar with good range parameters, but at the same time with poor scanning properties.
And I told you from the start that if what you said about RCS is correct, then VHF will never be developed/advertised as an anti stealth tool because their detection range against stealth aircraft will be less than X-band radar
And, do you want to know what is the operating frequency of these radars below?. Both in X-band.
Anyway, I don't want to be a radar operator that scans a small sector 60 * 60 in 1 minute 15 seconds.
As I said, this sector should be scanned in 10, maximum 15 seconds.
If scan time is absolutely important, nothing stop them from using a fraction of the array for shorter range quick scan and the rest for long range scan, we are in the age of AESA radar after all
Secondly, I don't have to argue with ITU, you should open a book and learn the different between free space basic transmission loss and atmospheric attenuation.
I didn't engage in any dispute with them , if you took my advice and opened a book, you will see that free space basic transmission loss and atmospheric attenuation are completely different things. Atmospheric attenuation is caused by the energy absorption of gas and molecules in the atmosphere, if you transmit radio wave in a vaccum, there is no atmospheric attenuation. Free space basic transmission loss is the lost caused by the spread of the radio beam over distance, you still have that even if you transmit radio wave in space vacuum. Atmospheric attenuation:
The comparison by Robert Wallace, the senior flight operation for F-35 and former chief of low observability for the B-2 is official, the chart given by Wu Jian Qi, the chief engineer of LC-8B, JY-27A manufacturer is official, the chart given by Lockheed Martin is also official .
There are already more than enough overwhelming evidences. You are just quibbling
The chart given by Wu Jian Qi has number on it, which can be used to deduce the stealth quantity
The comparison by Robert Wallace is straight forward and can be used to deduce the RCS
The charts and reduction percentages from LM slides are very straight forward and can be used to deduce the percentage of RCS reduction
The number given by Michael Hake is straight forward.
All these evidences support the same conclusion.
There is quite a big peak at around 65 degrees. Nevertheless, it quite an impossible task to ask someone to make an accurate angle estimation with his eye when is literally being attacked by a missile the size of a telephone pole coming at him through the cloud cover. So +- 15 or even 20 degree inaccurate is understandable
First, you got the sides mixed up.
Second, don't think that the US Air Force pilots are topographic critins. The cockpit is full of landmarks to determine the angle.
Thirdly, if you imagine the flight of the F-117 relative to the radar, you will understand that 50 degrees is the maximum at the end of the trajectory. The detection took place at a lower angle.
Firstly, the aircraft is pretty symmetrical so it doesn't matter
Secondly, when there is a telephone pole flying at you through the cloud cover at two - three time speed of sound then anyone can make inaccurate estimation, let alone something as small as the different of 50 and 65 degrees.
Thirdly, no. The detection was done by the P-18 radar, when the airplane got close, they tried to track it with the fire controlled radar, falling several times before finally acquired a lock and launch missile immediately. And also the aircraft was extremely close to the site, so even a small bank angle can lead to its tail making a 90 degrees with the ground radar
The thing is, how did they arrived at these numbers? did they made individual models for each airplane then test?, I don't think they did. And even if they do, what does their model look like?
And what does these number mean? average? min? max?
Models studied at the Central Scientific Research Institute of the Aerospace Forces of the Ministry of Defense of the Russian Federation (NII VVKO). Former name "2nd Scientific Research Institute of the Ministry of Defense"
As satisfied as I am about the more than 1000fold improvement for smaller target detection with the usage of a sapphire crystal for targets from the achievements of that photonics team in Australia I have some following questions below here which relate to the last posts being discussed here.
At 100 nautical miles if using a low frequency aerial target it will be seen as a 5.5km tall, 1.6km wide and 200 meter depth target. F-35 is claimed as 1200mph max speed, it covers 20 kms per minute(can use the Su-57 as an example to), And since the Nebo-M is considered a circular scan that gives target updates every 5-10 seconds if its travelling at a speed of 1200 mph pulling a hard left or right 1.66 to 3.33kms. So we can add 3.33km for height and width of the box to 8.83kms by 4.93kms.
35(.0001 ÷ 0.3) ^.25 at a 4.73km distance a .0001m2 target can be tracked with a buk-M3’s missile autonomously by the missile itself. http://www.1728.org/angsize.htm if we assume that the radar beam angle 120 degrees with a 4.73km distance the size of the entire radar beam horizontal angle would be 16.73kms with 8.83kms covered and if the Elevation angle is the same or smaller the 4.93km height can be covered. However the only thing I did not take into account is
1. 9M96MD and 40N6 are not only new missiles with active homing capabilities like the Buk-M3 missile but bigger in size which I assume they will see something smaller and farther than 0.3m2 passed 35kms.
2. Considering the flight ceilings of the 9m96MD and 40N6 it seems that more than half their flights they will be able to fly above the max flight ceilings current aircrafts are capable of. Meaning these host radars will be pointing their radar beams on top of highly reflective topside surface of aircrafts which could be considerable in RCS size compared to pointing a radar beam at the front of an aircraft.
Has this been covered before here using VHF or UHF radars while using just tracking capabilities of the missiles themselves?
Also since some 5th gen aircraft programs have a long term investment until 2070 how has stealth technology improved to keep up with the emergence of new radar capabilities like in the field of photonics?
“for example, take ground-based radar. Today, this radar is the size of a multi-story home, but using microwave photonics, the station can be installed on a standard KAMAZ truck. The effectiveness and range of the radar would be exactly the same, namely thousands of kilometers. Several of these mobile and small radar systems can be networked, which will only increase their characteristics.”
"The detection distance is very far, the energy conversion efficiency is up to 60%, the traditional radar is only 30%, and the noise is more than 100 times lower than the traditional radar, greatly improving the signal-to-noise ratio, for stealth target theory detection distance of more than 500 kilometers!"
"Unlike traditional radars, it will not be physically possible to silence ROFAR by traditional means of EW. The dynamic range of the photon crystal is about 200 DB. Modern electronic receiver, for comparison, has a range of 40 - 60 DB, and we modern EW complexes provide a signal to the entrance of the radio receiver - in 70-80 DB relative to its threshold sensitivity. Thus, the device that needs to receive the signal is displayed from a healthy state. Even after the interference in his inside there are still processes that do not allow him to work. But on Earth there is simply no energy source for a signal with a capacity greater than 200 DB, so this logic in the case of ROFAR simply does not work. It can be confused by so-called intellectual opposition, but this is a different story."
Tempest's radar technology will reportedly provide over 10,000 times more data than current systems. ‘Multi-Function Radio Frequency System’ will deliver a huge amount of data that equals to internet traffic of Edinburgh in a second, comparingly speaking."
Alexey Leonkov, a military expert of the magazine "Arsenal of the Fatherland" told about the revolutionary significance of the development in an interview with the Moscow Komsomolets.
"According to the analyst, the transition from electrons to photons will lead to the creation of a new generation of radars that will be able to process information using the electromagnetic waves of the microwave range. The speed of transmission of information will increase to hundreds of terabits per second, that is, the reflected signal will be processed instantly at all frequencies. Thus, it will be possible to increase the probability of identification of the target to 100%, radars will be able to detect any target. Alexey Leonkov believes it is important that the stations themselves will become smaller, but at the same time it will be much more effective, it will be more difficult for them to put interference. The new radiophoton radars will be 2-4 times smaller than Daryal. In addition, the thermal radiation will also decrease."
In the United Kingdom, average IP traffic will reach 23 Tbps in 2020, and busy hour traffic will reach 132 Tbps.
So to keep up with the future of photonic radars does that mean next gen stealth has to have a 100 to 1000fold improvement in stealth reduction on all sides?
The radars you cite are attached missile defense radars. Who are looking through a narrow sector. Narrow in elevation. If a ballistic missile passes through this sector, then escort and guidance radars will look there.
We're talking about surveillance radars, which are supposed to track aerodynamic objects in a wide sector.
As they say in Russia, "You mixed people and horses."
If scan time is absolutely important, nothing stop them from using a fraction of the array for shorter range quick scan and the rest for long range scan, we are in the age of AESA radar after all
By turning off part of the TRM, you will also reduce the area, and therefore the gain. That's what I'm talking about to you.
Only, why make a radar in order to then reduce its area, in such a "wild" way.
I didn't engage in any dispute with them , if you took my advice and opened a book, you will see that free space basic transmission loss and atmospheric attenuation are completely different things. Atmospheric attenuation is caused by the energy absorption of gas and molecules in the atmosphere, if you transmit radio wave in a vaccum, there is no atmospheric attenuation. Free space basic transmission loss is the lost caused by the spread of the radio beam over distance, you still have that even if you transmit radio wave in space vacuum.
In my opinion, I said everything.
You can ferry me over. Suddenly your calculator will miraculously give not 31 dB, but 2 dB.
If you do not like the ITU formula, you can use this one by expressing Pr - the receiver sensitivity.
I assure you this formula will give the same result.
There are already more than enough overwhelming evidences. You are just quibbling
The chart given by Wu Jian Qi has number on it, which can be used to deduce the stealth quantity
The comparison by Robert Wallace is straight forward and can be used to deduce the RCS
The charts and reduction percentages from LM slides are very straight forward and can be used to deduce the percentage of RCS reduction
The number given by Michael Hake is straight forward.
All these evidences support the same conclusion.
Secondly, when there is a telephone pole flying at you through the cloud cover at two - three time speed of sound then anyone can make inaccurate estimation, let alone something as small as the different of 50 and 65 degrees.
Thirdly, no. The detection was done by the P-18 radar, when the airplane got close, they tried to track it with the fire controlled radar, falling several times before finally acquired a lock and launch missile immediately. And also the aircraft was extremely close to the site, so even a small bank angle can lead to its tail making a 90 degrees with the ground radar
They found it P-15 (not P-18) at the bearing of 195 and range of 23.
P-15, by the way, decimeter band. At a distance of 15 km and a bearing of 210, the command sounded to turn on the missile guidance station (CHR-125). Then, within 10 seconds, they cannot find him СНР-125. And they find it on bearing 240. A salvo on course 250, defeat on course 270.
In any case, they found (CHR-125) from a smaller angle than the rocket arrived.
The thing is, how did they arrived at these numbers? did they made individual models for each airplane then test?, I don't think they did. And even if they do, what does their model look like?
Probably the same as the Chinese experts.
You have another problem. If you like the figures, you write it down as proof, if you don't like it, then you reject it.
The radars you cite are attached missile defense radars. Who are looking through a narrow sector. Narrow in elevation. If a ballistic missile passes through this sector, then escort and guidance radars will look there.
We're talking about surveillance radars, which are supposed to track aerodynamic objects in a wide sector.
As they say in Russia, "You mixed people and horses."
anti ballistic missile look through narrow elevation? In what way?. Most aircraft cruise below 60.000 ft (18 km), at 350 km the elevation is about 3 degree, at 250 km, the elevation is 4.5 degrees, at 100 km, the elevation is still only barely 10 degrees. On the other hand, ballistic missiles can climb to 2000 km, which mean at 1000 km the elevation is already 63 degrees. Also, anti ballistic missile doesn't look through narrow sector, it is quite the contrary
By turning off part of the TRM, you will also reduce the area, and therefore the gain. That's what I'm talking about to you.
Only, why make a radar in order to then reduce its area, in such a "wild" way.
You don't turn off part of the TRM, you can divide the array into subgroup that perform multi tasks. For example: target at high elevation only at very close range, so you only need very small array sub group for that, while for long range, the majority of the array can be used.
In my opinion, I said everything.
You can ferry me over. Suddenly your calculator will miraculously give not 31 dB, but 2 dB.
If you do not like the ITU formula, you can use this one by expressing Pr - the receiver sensitivity. View attachment 648125
I assure you this formula will give the same result.
Once again.
Firstly, you are still confusing between the free space path loss and atmospheric attenuation. They are completely different things as I already taught you earlier. free space path loss is very significant because it is the spread of signal density and you will have it even if you transmit in a vacuum. Atmospheric attenuation is the absorption of atmosphere and very small for frequency like X band and lower, it also doesn't exist in a vacuum.
Secondly, I already used the Dmax formula for the calculation that I gave you earlier.
They found it P-15 (not P-18) at the bearing of 195 and range of 23.
P-15, by the way, decimeter band. At a distance of 15 km and a bearing of 210, the command sounded to turn on the missile guidance station (CHR-125). Then, within 10 seconds, they cannot find him СНР-125. And they find it on bearing 240. A salvo on course 250, defeat on course 270.
In any case, they found (CHR-125) from a smaller angle than the rocket arrived.
I thought you only believe official sources, all the journalist and non government sources are garbage?. Now you resort to use a badly photoshopped image from Instagram? The name of the Instagram account is literally still on your photo
Probably the same as the Chinese experts. You have another problem. If you like the figures, you write it down as proof, if you don't like it, then you reject it.
I didn’t understand this document.
And the Chinese experts, what are the numbers for the F-22? Average and minimum?
No, it is the same. For the chinese radar scattering simulation, I can at least see what their model look like. In the simulation cited by tequila, I can also see the model and the method they choosen for simulation which is without canopy and radome cone. In both case, there are radar scattering graph to see the distribution of lobes. In case of the chart given by Wu Jian Qi, there is no number for the aircraft RCS, but there are comparative detection range and also the actual event where only the VHF radar detected the fighter and nothing else. Whereas in case of Ukrainian experts, they only given a generic value, since they aren't the one who made the fighter, how they get the value is important.
I will now reveal the SECRET of American stealth aircraft.
A computational electromagnetics model is used to predict the radar cross section of an object in software.
Scaled testing in chambers and full scale testing on outdoor RCS ranges is used to *validate and refine* the computational electromagnetics model. If the prediction does not match the measurement you go back and work on it until it does! That's the secret, and how the prediction gives high quality results.
This is exactly what some of the strange shapes seen at outdoor RCS ranges are for. Validating computational models with measurements.
That said, all we have to do is find a way to make airplanes out of whatever those cables at Tver are made from and we'll be invisible!
In the authoritative scientific journal Physical Review there was an article sponsored by Russian scientists from the NITU "MISIS" in Moscow. The article talks about the development of a unique metamaterial, among the many amazing properties of which and the ability to remain "invisible" for a whole range of electromagnetic radiation. Such metamaterial can reportedly be used in the creation of technology with unique stealth technologies (new stealth variants).
It is known that not only physicists from Moscow are involved in the creation of the technology, but also Greek scientists from the University of Crete. It should be noted that the work was carried out within the framework of Russian-Greek cooperation in the field of quantum technologies. The relevant contract was concluded in 2016. The cooperation is financed by both countries (RF and Greece) and provides for the creation of these metamaterials.
For reference: metamaterials - materials created artificially. They have a heterogeneous internal structure that allows the electromagnetic wave to be lost inside such a material. This can allow the use of metamaterials as a kind of "invisible cap" for modern combat vehicles. It is reported that metamaterials can be suitable for the creation of promising computing and communication systems with photonic principles rather than electric ones."
The experimental part of our study is the created unique metamaterial, which is a small flat lattice of so-called metamolecules, cut laser sharp from a single piece of ordinary steel. By adding a non-linear semiconductor, the metamater will become a reconfigurable screen for STELS technology, a set of ways to reduce the radar visibility of combat vehicles in radio, infrared and other areas of the spectrum.
Elongated metal objects like antennas or cell towers have an electric response—a signal that appears in response to an impact. To hide such an object from radar, the object must scatter light, like an object with a magnetic response, which is very weak. This was accomplished by scientists from the Russian-Italian scientific collaboration, in the framework of the "ANASTASIA" project (Advanced Non-radiating Architectures Scattering Tenuously And Sustaining Invisible Anapoles), named after the Grand Duchess of the Russian Empire Anastasia Romanova.
"We came up with a special coating based on an ideal magnetic dipole scatterer that turns an elongated metal object with an electric response into an object with a magnetic response," said one of the researchers, associate professor at the NUST MISIS Superconducting Metamaterials Laboratory, Alexey Basharin. "This has become possible due to the anapole state of the coating material, which lowers the electric type scattering to the level of the magnetic one and even lower. As a result, the object becomes invisible."
The first of the possible applications of the new coating will be Stealth technology for military and civilian purposes—to hide various elongated objects, such as aircraft landing gear, antennas and various sensors, ship masts and airport towers. The developers emphasize, that if the task of hiding these objects from enemy radars is trivial, the task of electromagnetic compatibility of antennas on satellites is vital: antennas must not affect each other. And this will be possible only if they are invisible.
ST. PETERSBURG, Russia, May 21, 2020 — Researchers at ITMO University and the University of Exeter have developed a metamaterial capable of changing its optical properties without any mechanical input. The new metamaterial could improve the reliability of complex optical devices while also making them cheaper to manufacture.
Thanks to their complex periodical structure, metamaterials are relatively independent from the properties of their components. Such structures can be volumetric or flat, as is the case with metasurfaces.
“Metasurfaces allow us to achieve many interesting effects in the manipulation of light,” ITMO researcher Ivan Sinev said. “But these metasurfaces have one issue: How they interact with light is decided right in the moment when we design their structure. When creating devices for practical use, we would like to be able to control these properties not only at the outset, but during use, as well.”
I hope the road to metamaterials improve to the point that its stealth signature would surpass reflect away designs and material absorption later. Don't care if that kills all the fun in aviation forums discussing the Su-57
anti ballistic missile look through narrow elevation? In what way?. Most aircraft cruise below 60.000 ft (18 km), at 350 km the elevation is about 3 degree, at 250 km, the elevation is 4.5 degrees, at 100 km, the elevation is still only barely 10 degrees. On the other hand, ballistic missiles can climb to 2000 km, which mean at 1000 km the elevation is already 63 degrees. Also, anti ballistic missile doesn't look through narrow sector, it is quite the contrary
Ballistic missiles have a static trajectory. Therefore, there is no need to scan at a wide angle (elevation angle). This also supports the smaller antenna height. By eye, the aspect ratio of TPU-2 is about 1: 3. With an effective area of 6 m2, we get sides of about 1.4 * 4.3. The solid angle is about 1 square degree at a wavelength of 0.03. Based on my experience, I know that the scanning sector of such radars in standby mode is 90 * 15. Scanning with such a beam will take 27 seconds. Which is quite acceptable for such radars.
I'm tired. I showed you that two radars with the same scanning and energy properties, but different in wavelength (1.1 m and 0.03 m) will have different losses. This difference is 31 dB.
Do you agree with that?
We walk in circles.
1. Chinese experts are not an official source, just like Ukrainian experts. The point is simple. You like the Chinese number, but not the Ukrainian one.
2. LM presentation, does not contain figures. The air defense loss graph cannot be compared with the RCS numbers.
3. The words of the LM representative do not contain figures, but only abstractions that can be interpreted as you like.
4. The article of the Air Force Major, has figures. But they were taken from a certain writer. Where did the writer get these figures- I don't know.
In addition, these figures do not agree with other sources for a small RCS. They claim that the RCS B-2 is less than the F-117.
I will not argue about this. Although Anich in his book talks about the P-15. It is the P-15 that is attached to the S-125 divisions. The P-18 is assigned to the S-200 divisions.
But again, I agree with you so as not to give you a reason to cling to words.
Understand, if the person was not sure, then he would have picked up a more general word. But he indicates exactly the value (figure).
At the same time, non-standard direction angles, such as 45, 90, etc. And clearly 50.
I thought you only believe official sources, all the journalist and non government sources are garbage?. Now you resort to use a badly photoshopped image from Instagram? The name of the Instagram account is literally still on your photo
I know that Have Blue was calculated for CRAY-1.
The transition from the faceted form F-117 to the more aerodynamic form of the F-22 is due to the increase in computing power in the mid-80s.
But you must admit that the last word is still for natural experiments. And it is impossible to judge RCS only by computer modeling.
Colleagues, I apologize for the offtopic. Although the topic has long since departed from its name. I am not very familiar with the threads of this forum.
Prompt a stream of books.
I am intrigued by the books of David C. Aronstein
Have Blue and the F-117A: Evolution of the "Stealth Fighter"
and Advanced Tactical Fighter to F-22 Raptor: Origins of the 21st Century Air Dominance Fighter
No, it is the same. For the chinese radar scattering simulation, I can at least see what their model look like. In the simulation cited by tequila, I can also see the model and the method they choosen for simulation which is without canopy and radome cone. In both case, there are radar scattering graph to see the distribution of lobes.
I understand that you will now say that they are complete fools, because you will not like this figure. But they did the same as the Chinese specialists.
In case of the chart given by Wu Jian Qi, there is no number for the aircraft RCS, but there are comparative detection range and also the actual event where only the VHF radar detected the fighter and nothing else.
We have already found out that we do not know which radars he is comparing on his diagram. And to estimate the RCS from this picture is like looking for numbers in the LM presentation by the percentage of losses from air defense. There is nothing that one could catch on to get at least some numbers. There are not even indirect signs by which something could be determined
Ballistic missiles have a static trajectory. Therefore, there is no need to scan at a wide angle (elevation angle). This also supports the smaller antenna height. By eye, the aspect ratio of TPU-2 is about 1: 3. With an effective area of 6 m2, we get sides of about 1.4 * 4.3. The solid angle is about 1 square degree at a wavelength of 0.03. . Scanning with such a beam will take 27 seconds. Which is quite acceptable for such radars.
Firstly, whether ballistic missile have static trajectory or not is irrelevant, you are searching to find them inside a volume of space, ballistic missiles can climb to much higher altitude so the elevation is higher. We are basically comparing between 2000 km in height vs about 18 km in height, you need much higher elevation to track ballistic missiles.
Secondly, the area of TPY-2 isn't 6 m2 but 9.2 m2.
and its side isn't 1.4 meter unless you think these guys in this photo are all dwarf
I'm tired. I showed you that two radars with the same scanning and energy properties, but different in wavelength (1.1 m and 0.03 m) will have different losses. This difference is 31 dB. Do you agree with that?
You wouldn't be tired if you just took my advice, open a book and learn the different between atmospheric attenuation and basic free space basic path loss
Secondly, as I explained earlier, the free space path loss is caused by the spread out of radio wave as they propagate through space, it is literally the inverse square law working.
Before you argue "why does the loss increase with frequency if they both follow the inverse square law", remember that you compared the two radar with same beam width, but one radar use VHF frequency and the other one use X-band. That lead to the aperture area of your VHF radar being 111.5 m2 and the aperture area of the X-band radar being 0.082 m2, in other words, the VHF radar in your example is 1359 times bigger than the X band radar. Because this free space path loss is literally the spread of beam over distance, a bigger radar aperture will collect signal from greater area, and that why the loss is less for bigger antenna even though both follow the inverse square law principles. I repeat again, this has nothing to do with atmospheric attenuation
However, when you put everything inside Rmax equation, and there isn't an insane size different between the X-band and VHF radar then X-band radar win hand down in term of detection range. That why your claim that RCS at VHF is only 5 times bigger than in X-band make no sense, because if that is the case than X-band is a much better anti stealth tool.
We walk in circles.
1. Chinese experts are not an official source, just like Ukrainian experts. The point is simple. You like the Chinese number, but not the Ukrainian one.
2. LM presentation, does not contain figures. The air defense loss graph cannot be compared with the RCS numbers.
3. The words of the LM representative do not contain figures, but only abstractions that can be interpreted as you like.
4. The article of the Air Force Major, has figures. But they were taken from a certain writer. Where did the writer get these figures- I don't know.
In addition, these figures do not agree with other sources for a small RCS. They claim that the RCS B-2 is less than the F-117.
1. Because the Chinese number actually reference a real life incident
2. Yes , it can be compared with number, they very carefully divided the graph into equal section, 5 folds reduction in detection range can be translate to percentage reduction in RCS
3. There is nothing particularly abstraction about golf ball or marble, they have explained before that they often used a ball to talk about RCS as the RCS of it is independent of aspect so easier to imagine.
4. The Air Force Major with all his experiences certainly think the numbers are accurate enough to cite
5. Depend on frequency, at lower frequency it isn't hard to imagine B-2 will have much lower RCS
Understand, if the person was not sure, then he would have picked up a more general word. But he indicates exactly the value (figure).
At the same time, non-standard direction angles, such as 45, 90, etc. And clearly 50.
He gave his estimate by his naked eye, that it. There is no requirement for him to be absolutely accurate with his estimate and given the condition he was in, it is quite impossible for him make super accurate estimate. In high stake situation, people have been shown to misidentify criminal suspects, pilots have been shown to mistaken between the sky and the ocean and die. Those are the things which are much harder to mistaken and people still misidentify them, nevermind something small like a different between 50-65 degrees or even his bank angle.
On the other hand, I would say that their simulation certainly better than the vague number from the Ukraine. But unlike you, I look deeper than the surface, I care about the model as well
At first, the number seem weird for a stealth aircraft, 10 dBsm at front aspect is quite high even when consider that the model is a perfect conductor and has no RAM or edge treatment. Then I look at their scattering chart and even the breakdown between vertical and horizontal polarization and I find another strange characteristic. The very strong 12 dBsm scattering lobe is directly at the front with very narrow angle. What type of reflector has that scattering characteristic? A flat plate.
Then I look at their model and it all clicked instead of modelling an S shaped inlet duct, they literally covered it with a flat metal plate. That is why they have such a strong reflection lobes directly in front of the aircraft an in such a narrow angle.
Isn't it strange that they spend such a long time to do such a detail simulation but overlook such obvious detail? Then I read their study and realize that they mentioned that as the primary reason for the high RCS. If you read their study, then you should know the reason for the high RCS value as well.
The S-duct is very important in RCS simulation because not only that it is a strong source of reflection, it is probably the only place on the stealth aircraft where the RAM absorption rating get accumulated to extremely high value of 50-60 dB due to multiple bounce of the signal. I don't blame them though, most simulation doesn't do the inlet correctly or just out right ignore it
We have already found out that we do not know which radars he is comparing on his diagram. And to estimate the RCS from this picture is like looking for numbers in the LM presentation by the percentage of losses from air defense. There is nothing that one could catch on to get at least some numbers. There are not even indirect signs by which something could be determined
There detection range show as km in the photo so you can't say there is no number. The VHF is JY-27, and while there is no mentioned of the exact type of the cm band radar, it is quite safe to conclude that it is something that does similar task to JY-27 and not some crazy comparison like a VHF air defense radar and a missile seeker.
Models studied at the Central Scientific Research Institute of the Aerospace Forces of the Ministry of Defense of the Russian Federation (NII VVKO). Former name "2nd Scientific Research Institute of the Ministry of Defense"
A properly designed and written simulation will give results that are very close to reality. I don't know what your experience simulation is with computer modeling systems, but they are used because they do give high quality results.
American Physical Society, Report of the APS Study Group on Boost-Phase Intercept Systems for National Missile Defense, Vol. 2, July 2003, p. 177.
Specifically, this study says an effective aperture of 6 m2 and a physical aperture of 9.2 m2
Honestly, I don't understand what kind of monster it is. And what is its purpose. They say that this is generally a radar for the HAARP project.
It is also known that not all modules are installed, so it is difficult for me to determine the exact dimensions of the antenna.
Before you argue "why does the loss increase with frequency if they both follow the inverse square law", remember that you compared the two radar with same beam width, but one radar use VHF frequency and the other one use X-band. That lead to the aperture area of your VHF radar being 111.5 m2 and the aperture area of the X-band radar being 0.082 m2, in other words, the VHF radar in your example is 1359 times bigger than the X band radar. Because this free space path loss is literally the spread of beam over distance, a bigger radar aperture will collect signal from greater area, and that why the loss is less for bigger antenna even though both follow the inverse square law principles. I repeat again, this has nothing to do with atmospheric attenuation
However, when you put everything inside Rmax equation, and there isn't an insane size different between the X-band and VHF radar then X-band radar win hand down in term of detection range. That why your claim that RCS at VHF is only 5 times bigger than in X-band make no sense, because if that is the case than X-band is a much better anti stealth tool.
Of course, I took with the same beam width and gain. How else?
Listen to yourself ...
You make an x-band radar so that its energetic characteristics coincide with the long-wave radar, you increase the gain by increasing the area. Thereby reducing the beam width.
Yes, you have created an x-band radar that has the same size, range, but very long scan times.
And now you say that this radar is better than the long-wave one. Than? The size is the same, the scan time of the standard 60 * 60 sector is 10 minutes instead of 10 seconds.
Don't you find it funny yourself?
You nobly forgive me for my English.
91Н6Е in static anti-missile defense mode scans the sector 25 * 20 (500 square degrees) or 60 * 30 (1800 square degrees). For TPY, I took an average of 1350 square degrees.
2. Yes , it can be compared with number, they very carefully divided the graph into equal section, 5 folds reduction in detection range can be translate to percentage reduction in RCS
Dismiss me from looking for a black cat in a black room. I'm not going to look for hidden meanings where there are none.
There will be numbers - there will be a conversation.
He gave his estimate by his naked eye, that it. There is no requirement for him to be absolutely accurate with his estimate and given the condition he was in, it is quite impossible for him make super accurate estimate. In high stake situation, people have been shown to misidentify criminal suspects, pilots have been shown to mistaken between the sky and the ocean and die. Those are the things which are much harder to mistaken and people still misidentify them, nevermind something small like a different between 50-65 degrees or even his bank angle.
Then I look at their model and it all clicked instead of modelling an S shaped inlet duct, they literally covered it with a flat metal plate. That is why they have such a strong reflection lobes directly in front of the aircraft an in such a narrow angle.
Show me in any of the simulations you have given before, is the air intake plugged?
Here's the fun part, but later.
Until then, answer the question.
Do you trust this article?
The characteristic feature of stealth technology is a significant reduction in the effective scattering area. Invisible is called an aircraft, which has this figure of less than 0.4 sq m.
As noted by Kornev, such an aircraft will not remain invisible to modern radar stations, but its detection causes a number of difficulties, negatively affecting the responsiveness of the air defense troops.
"Under certain conditions and at certain angles, the invisible can be overlooked, especially at long distances, which hypothetically allows the enemy aircraft to perform a combat mission. As far as I understand, in order to prevent such a development, RTI, together with other enterprises, has developed a method that captures the radar shadow," Says Kornev.
"Now it is too early to talk about the imminent implementation of a new method of breeding moving objects. To date, it has been proven that it is theoretically possible. There's still a lot of work to do. I think it's going to take about seven years. But if all goes well, this method will give Russia a noticeable advantage on the battlefield," Denisentsev said.
Yuri Knutov believes that scientists will certainly bring the invention to practical implementation, as the military is certainly interested in it. According to the analyst, the new method of selecting moving objects almost 100% guarantees the fixation of stealth-based devices over long distances.
"In my opinion, this is a huge breakthrough, which allows you to display on the screen so-called invisibles. It is important that with the help of synthesized aperture scientists were able to reduce the level of diaper errors. As a result, the principle of radar has been developed, which will detect any shadow, and the computer will calculate its exact location, which will allow the air defense forces to make a timely decision on counteraction," Knutov concluded.
Reported before, but it seems they gave a time estimate for its implementation later like seven years. I am wondering if anyone has heard of a method elsewhere before in regards to stealth aircrafts detection?
"I cannot imagine the B-2 having been designed without the influence of his work," Dr. Mitzner added. "Let me put it this way: without Ufimtsev, today's stealth aircraft would probably have looked the way the speculative artists portrayed them, before their real shapes were publicly disclosed"
"Rosetta Stone breakthrough for stealth technology" as said directly by Ben Rich -the Director of the team at SkunkWorks charged to carry on the XST program.
If all this involves complex math for making stealth and trying to defeat stealth at the end than why are the Russians not 1st or 2nd place other than the U.S. and Chinese students competing for top 2 spots? I am not even getting started with all the other crazy shit military related projects they are doing.
The way I understand that: the shadow of a plane can be noticed in a bistatic system, in a monostatic one that looks directly to the sky that looks difficult. But a system like an OTH radar is always receiving ground clutter, so the shadow of a stealth plane blocking known returns would be noticeable. That would be a tool even if modern planes are designed to be very stealthy against very long wavelengths... a pity that those "incredible" -70 dBsm in the end are only going to help detecting the B-21 better
If all this involves complex math for making stealth and trying to defeat stealth at the end than why are the Russians not 1st or 2nd place other than the U.S. and Chinese students competing for top 2 spots?
If all this involves complex math for making stealth and trying to defeat stealth at the end than why are the Russians not 1st or 2nd place other than the U.S. and Chinese students competing for top 2 spots? I am not even getting started with all the other crazy shit military related projects they are doing.
Maybe that is why they are doing better with autonomous flights with the Su-70 because that involves high level of programming for everything to work right.
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so tell me, how can they get superior range from VHF radar?
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