Sukhoi PAK FA

[p2prada]

one has to learn to walk or even crawl before running....

Huh?

You don't see a problem with that statement? It says PAK FA will not be higher than the F-22 when we KNOW that is BS. The Raptor is like .03m^2

There are no average RCS figures available for these aircraft. It is always taken from the front and will always be much higher from different aspects.

ROFL.

 

[SilentKiller]

Huh?

What i meant that what ever comes out of PAKFA, indian should be fully involved even if its new or less than some western tech as we will come to know its basics!!

 

[Austin]

Better Quality Video of T-50-4

T-50 FGFA - YouTube

 

[average american]

B2 Bomb Run - YouTube

The radar cross section (RCS) of a target is defined as the effective area intercepting an amount of incident power which, when scattered isotropically, produces a level of reflected power at the radar equal to that from the target. RCS calculations require broad and extensive technical knowledge, thus many scientists and scholars find the subject challenging and intellectually motivating. This is a very complex field that defies simple explanation, and any short treatment is only a very rough approximation.

The units of radar cross section are square meters; however, the radar cross section is NOT the same as the area of the target. Because of the wide range of amplitudes typically encountered on a target, RCS is frequently expressed in dBsm, or decibels relative to one square meter. The RCS is the projected area of a metal sphere that is large compared with the wavelength and that, if substituted for the object, would scatter identically the same power back to the radar. However, the RCS of all but the simplest scatterers fluctuates greatly with the orientation of the object, so the notion of an equivalent sphere is not very useful.



Different structures will exhibit different RCS dependence on frequency than a sphere. However, three frequency regimes are identifiable for most structures. In the Rayleigh region at low frequencies, target dimensions are much less than the radar wavelength. In this region RCS is proportional with the fourth power of the frequency. In the Resonance or Mie Region at medium frequencies, target dimensions and the radar wavelength are in the same order. The RCS oscillates in the resonance region. In the Optical Region of high frequencies, target dimensions are very large compared to the radar wavelength. In this region RCS is roughly the same size as the real area of target. The RCS behaves more simply in the high-frequency region. In this region, the RCS of a sphere is constant.

In general, codes based on the methods-of-moments (MOM) solution to the electrical field integral equation (EFIE) are used to calculate scattering in the Rayleigh and resonance regions. Codes based on physical optics (PO) and the physical theory of diffraction (PTD) are used in the optical or high-frequency region. The target's electrical size (which is proportional to frequency and inversely proportional to the radar wavelength) that determines the appropriate algorithm to calculate the scattering. When the target length is less than 5 to 10 wavelengths, the EFIE-MOM algorithm is used. Alternatively, if the target wavelength is above 5 to 10 wavelengths, the PO-PTD algorithm is used.

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 .

A conventional fighter aircraft such as an F-4 has an RCS of about six square meters (m2), and the much larger but low-observable B-2 bomber, which incorporates advanced stealth technologies into its design, by some accounts has an RCS of approximately 0.75 m2 [this is four orders of magintude greater than the widely reported -40dBm2 ]. Some reports give the B-2 a head-on radar cross section no larger than a bird, 0.01 m2 or -20dBm2. A typical cruise missile with UAV-like characteristics has an RCS in the range of 1 m2; the Tomahawk ALCM, designed in the 1970s and utilizing the fairly simple low-observable technologies then available, has an RCS of less than 0.05 m2.

The impact of lowered observability can be dramatic because it reduces the maximum detection range from missile defenses, resulting in minimal time for intercept. The US airborne warning and control system (AWACS) radar system was designed to detect aircraft with an RCS of 7 m2 at a range of at least 370 km and typical nonstealthy cruise missiles at a range of at least 227 km; stealthy cruise missiles, however, could approach air defenses to within 108 km before being detected. If such missiles traveled at a speed of 805 km per hour (500 miles per hour), air defenses would have only eight minutes to engage and destroy the stealthy missile and 17 minutes for the nonstealthy missile. Furthermore, a low-observable LACM can be difficult to engage and destroy, even if detected. Cruise missiles with an RCS of 0.1 m2 or smaller are difficult for surface-to-air missile (SAM) fire-control radars to track. Consequently, even if a SAM battery detects the missile, it may not acquire a sufficient lock on the target to complete the intercept.

Radar scattering from any realistic target is a function of the body's material properties as well as its geometry. Once the specular reflections have been eliminated by radar absorbing materials, only nonspecular or diffractive sources are left. Non-specular scatterers are edges, creeping waves, and traveling waves. They often dominate backscattering patterns of realistic targets in the aspect ranges of most interest. The traveling wave is a high frequency phenomenon. Surface traveling waves are launched for horizontal polarization and grazing angles of incidence on targets with longs mooth surfaces. There is little attenuation from the flat smooth surface, so the wave builds up as it travels along the target. Upon reaching a surface discontinuity, for example an edge, the traveling wave is scattered and part of it propagates back toward the radar. The sum of the traveling waves propagating from the far end of the target toward the near end is the dominant source to the target radar cross section.

The radar cross section (RCS) of a target not only depends on the physical shape and its composite materials, but also on its subcomponents such as antennas and other sensors. These components on the platforms may be designed to meet low RCS requirements as well as their sensor system requirements. In some cases, the onboard sensors can be the predominant factor in determining a platform's total RCS. A typical example is a reciprocal high gain antenna on a low RCS platform. If the antenna beam is pointed toward the radarand the radar frequency is in the antenna operating band, theantenna scattering can be signi?cant.

The traditional measure of an object's scattering behavior is the RCS pattern which plots the scattered field magnitude as a function of aspect angle for a particular frequency and polarization. Although suitable to calculate the power received by a radar operating with those particular parameters, the RCS pattern is an incomplete descriptor of the object's scattering behavior. While the RCS pattern indicates the effect of the scattering mechanism, it does not reveal the physical processes which cause the observed effect. In contrast, imaging techniques, which exploit frequency and angle diversity to spatially resolve the reflectivity distribution of complex objects, allow the association of physical features with scattering mechanisms. These processes, therefore, indicate the causal components of the overall signature level observed in RCS patterns.

http://www.globalsecurity.org/military/world/stealth-aircraft-rcs.htm

 

[average american]

PAK FA had an RCS of 0.5sqm.
F22 is .0001

A B2 bomber will have much lower radar cross signature than a PAK FA

Posted vidio by mistake but now the B2 can carry 212 GBU39 smart bombs.

 

[p2prada]

PAK FA had an RCS of 0.5sqm.
F22 is .0001

No.

Wrong comparison.

 

[average american]

Detection range by a modern AWACS and RCS of some fighters:

* F-15C & Su-27 (RCS = 10~15m2): 450 ~ 600 km
* Tornado (RCS = 8 m2): 420 ~ 500 km
* MIG-29 (RCS = 5 m2): 370 ~ 450 km
* F/A-18C (RCS = 3 m2): 330 ~ 395 km
* F-16C (RCS = 1.2 m2): 260 ~ 310 km
* JAS39 (RCS = 0.5 m2): 210 ~ 250 km
* Su-47 (RCS = 0.3 m2): 185 ~ 220 km
* Rafale (RCS = 0.1~0.2 m2): 140 ~ 200 km
* F-18E (RCS = 0.1 m2): 140 ~ 170 km
* MIG-42 (RCS = 0.1 m2): 140 ~ 170 km
* EF2K (RCS = 0.05~0.1 m2): 120 ~ 170 km
* F-35A (RCS = 0.0015 m2): 50 ~ 60 km
* F/A-22 (RCS < or = 0.0002~0.0005 m2): < or = 30 ~ 45 km
* PAK-FA (RCS = 0.5 m2): 210 ~ 250 km

 

[average american]

I dont see that the PAK FA is stealthy.

 

[Defcon 1]

I dont see that the PAK FA is stealthy.

Thats because your previous post was BS and was not backed by reliable sources.

 

[average american]

Fine, show me yours that proves it.

 

[Defcon 1]

Fine, show me yours that proves it.

If there was any I would have shown it, the RCS of both F22 and PAK FA can only be estimated, not proved.

 

[average american]

I think India has realized the so called PAK-FA project is desperate Russian attempt to gain some place on future World's fighter market dominated by Western stealth designs (upper price-tag segment) and low-cost Chinese fighters. As you probably know China has begun to push Russia out from Third World's arms markets. Many Chinese designs are comparable with their Russian counterparts yet being cheaper. That obviously means Russia won't be able to sell the same amount of Flankers and Fulcrums as before. Thus the only logical move for Russians is to push forward next-generation fighter project. However this is very tricky task in present Russian situation because:


- in overall Soviet aircraft industry was always behind the West

- during last twenty years Russian aviation industry was sharply degraded

- now Russia cannot develop even simple useful UAV so has to buy them in Israel

- Russia never shown signs of possessing true stealth technology while US have forty years long experience in this area and spent about 250 billion dollars in total on it developing several generations of stealth designs

Taken all above into account it is virtually impossible that Russia could create indigenous 5th generation stealth fighter. This is not that league anymore - no money, no high-tech found out there. That is why Russia after almost ten years of development unveiled some empty test-bed airframe (lack of new engines, radar(s), IRST, avionic & ECM systems, stealth coating, armament - all of them will have to be develop and integrate in the future, some are based on old stuff) and made propaganda show: "We catch up Americans, we have our own F-22!". In reality PAK-FA was declassified to gain new serious foreign investors. You should remember Russians had already tried to find such a foreign partner before PAK-FA first presentation: Brazil and Venezuela come to mind. Yet they managed to attract only India in joint FGFA project being in short two-sit PAK-FA version. Both sides agreed on such project's scheme: financing on fifty-fifty base, each side develops those parts of fighter design it mastered better so far, finally full technology and production transfer to India are to take place.

So I am sure PAK-FA is in fact Russian part of FGFA project and if India pulled out of this project (buying F-35 instead) Russia alone would not be able to finish it. Anyway two so backward in aviation high-tech stuff partners cannot design fighter comparable with F-22 or even F-35. I suppose Indian money and present Russian technology level combined should create in ten to fifteen years some...larger Eurocanard at best.

The problem is fighters are part of a system and as such comparing just 2 fighters is pointless.

That is why India is hedging its bets by buying Rafales but India has so much invested, so many jobs, and so much poltical face saving they have to take in to account if they bail out on the PAK FA

 

[p2prada]

I dont see that the PAK FA is stealthy.

Thats because your previous post was BS and was not backed by reliable sources.

You have your answer there.

Okay, let me explain this.

There is something called Frontal RCS and then average RCS. Then there are other aspects involved too, like side, rear and from various other angles.

For a stealth aircraft, the frontal RCS is the smallest RCS, that is because it is designed so. So, when you gave that figure for F-22, it was for the frontal RCS. While the figure you gave for PAKFA was average RCS. See the difference.

Now, look at this figure,

This is the F-35.

The red color indicates that the aircraft is visible from those sides while the green color shows it is very low observable from that angle. Yellow indicates low observable state. You add whatever RCS figure you get from all aspects and then take an average, that's how you get your average RCS figure.

This is supposedly a RCS diagram of a Su-27.

You will notice the side aspect is the biggest because of the vertical tail fins.

Side aspect is around 40m2. Frontal aspect is 15m2. From 20 deg angle, you will see 10m2.

For the average between the 3 you will get (40+15+10)/3 = 21.66m2. Perhaps why the Su-27 is supposed to have an average RCS of around 20m2. So, now do you see how it works.

Look at the F-35 diagram again. Let's assume the frontal aspect is 0.001m2. Side aspect may be 0.5m2. At 20 degrees it may be 0.01m2. I don't know I am just speculating so you get the point.

If we take an average we will get (0.001+0.5+0.01)/3 = 0.17m2. So, you see what happened here. The average will always give you a much larger figure than the frontal RCS which is supposed to be the smallest on stealth fighters.

So, when you talk BS you get caught for BS.

 

[average american]

90 percent in kills in modern combat is by whom detected their enemy plane first 80 percent of the kills the pilot did not even know he was under attack. I would expect the most important target and theat is whom ever is comming toward you so thats why the head on radar signature is so important. While the shape is important, the planes composits and radar absorbing qualities are just as or more important, either way the PAK FA signature is going to be up to 5000 times larger the F22.

 

[average american]

Generation 1: Jet propulsion (F-80, German Me 262).

Generation 2: Swept wings; range-only radar; infrared missiles (F-86, MiG-15).

Generation 3: Supersonic speed; pulse radar; able to shoot at targets beyond visual range ("Century Series" fighters such as F-105; F-4; MiG-17; MiG-21).

Generation 4: Pulse-doppler radar; high maneuverability; look-down, shoot-down missiles (F-15, F-16, Mirage 2000, MiG-29).

Generation 4+: High agility; sensor fusion; reduced signatures (Eurofighter Typhoon, Su-30, advanced versions of F-16 and F/A-18, Rafale).

Generation 4++: Active electronically scanned arrays; continued reduced signatures or some "active" (waveform canceling) stealth; some supercruise (Su-35, F-15SE).

Generation 5: All-aspect stealth with internal weapons, extreme agility, full-sensor fusion, integrated avionics, some or full supercruise (F-22, F-35, PAK-FA).

Potential Generation 6: extreme stealth; efficient in all flight regimes (subsonic to multi-Mach); possible "morphing" capability; smart skins; highly networked; extremely sensitive sensors; optionally manned; directed energy weapons.

I would rate a T 50 as 4.5 as it has some stealth and other charistics of 5th generation planes, I would rate F22 and F35 5.5 because they have directed energy weapons. I have been watching the subject of directed energy weapons for years. Russia has one called the Testle or Testi,. There was a lot on the subject for a while and then all of sudden the scientist working in that area shut up and the web sites seem to close down. But the rumors continue about the F22 and F35 directed energy weapons, I hear about ranges for 6 or 7 miles to 75 miles.

 

[average american]

90 percent in kills in modern combat is by whom detected their enemy plane first 80 percent of the kills the pilot did not even know he was under attack. I would expect the most important target and theat is whom ever is comming toward you so thats why the head on radar signature is so important. While the shape is important, the planes composits and radar absorbing qualities are just as or more important, either way the PAK FA signature is going to be up to 5000 times larger the F22.

Tesla Weapons - YouTube

 

[Austin]

While the shape is important, the planes composits and radar absorbing qualities are just as or more important, either way the PAK FA signature is going to be up to 5000 times larger the F22.

Post of the day

 

[p2prada]

Hmm, you are now officially the certified comedian of DFI.

 

[t_co]

90 percent in kills in modern combat is by whom detected their enemy plane first 80 percent of the kills the pilot did not even know he was under attack. I would expect the most important target and theat is whom ever is comming toward you so thats why the head on radar signature is so important. While the shape is important, the planes composits and radar absorbing qualities are just as or more important, either way the PAK FA signature is going to be up to 5000 times larger the F22.

Tesla Weapons - YouTube

Why is that funny?

 

[jackprince]

Why is that funny?

5000 times is a bit much, don't you think so?