Noon, XXI century. But some people continue to persistently deny the role of modern technology. Especially if the conversation concerns foreign samples of military equipment. Especially if they are stealth. Then uhh, the discussion will be hot.
However, burn about this topic is not as dangerous as before. At present, the whole generation of modern technology comes into service with the Russian Armed Forces, whose design contains the very technology “stealth”.
This material presents an analysis of the article “On invincible stealth,” recently published on the pages of one popular Internet resource. In my opinion, that article is replete with various inaccuracies and, in general, has the wrong message, aimed at underestimating the role of stealth technology in modern combat.
Stealth is not invisibility for radars, stealth is only "low" visibility.
The Russian word “invisible” was coined by the Russian-language media. Abroad, "Stealth" has remained "stealth" (which means "secretly, covertly").
It is not clear why the author took the word “small” in quotes. The effect of reducing visibility exists and is proven in practice. We can judge how small he is by the facts below.
Stealth is perfectly visible in the optical range, near IR, far IR
For years, 50 has been the main and primary means of detecting airborne targets. Low attenuation of electromagnetic waves in the atmosphere allows to obtain long detection ranges in all weather conditions.
The author deliberately disingenuous, switching the reader's attention to the optical and infrared ranges, although with the same success it is possible to declare the visibility of “stealth” in the ultraviolet.
Tear off your monitor for a second and look from the depths of the room at the window. There is a fly on the window. Barely visible point on the glass. This is how a pilot fighter sees a fighter from a distance of five kilometers. In general, in the century of radar and supersonic speeds at large (and even medium) distances, it is useless to rely on the visible range.
Optics helped only once. The most intelligible of all versions of the destruction of F-117 over Belgrade is the use of an optical guidance channel: the anti-aircraft gunners accidentally saw a brazen “stealth” flying below the clouds, and managed to launch a rocket. This is indicated both by the characteristics of the C-125 air defense system (“Karat-2” television viewer) and the testimony of the incident participants themselves - battery commander Zoltan Dani and the pilot of the Nighthouk shot down Dale Zelko (shot down when the lower edge of the clouds pierced). More luck was not repeated. Although, according to NATO, the clumsy stealth of the first generation made over 700 sorties over Yugoslavia.
An optical-location station (OLS) helps pilots of the modern “Su”, but this technique is still focused on close air combat. While the technology also does not stand still: there are proven ways to reduce the infrared signature of the aircraft (mixing exhaust gases with cold air). Note the flat nozzles of the F-22 engines. Or the stern part of the F-117 and B-2 stealth bomber: it is designed in such a way as to exclude the possibility to “look” into the engine nozzles from the lower hemisphere. However, that is not the point.
At medium and large distances, the main and only means of detection remains the radar.
That is why stealth has such chopped forms and many parallel edges and edges.
Fair observation. Parallelism of edges and edges is the basis of modern stealth technology. As well as:
- the requirement of an internal suspension of armaments;
- masking of engine compressor blades (curved air intakes, radar blockers);
- with the exception of protruding parts on the surface of the fuselage and wing (antennas, sensors, LDPE);
- installation of a cabin-free lantern;
- improving the quality of assembly, the use of large-sized panels of complex shape and a decrease in the gaps between the joints of cladding panels;
- “sawtooth” shape of the edges of the holes;
- as well as auxiliary measures in the form of ferromagnetic paints and radio-absorbing coatings.
... To be detected by a certain hypothetical radar not at a distance of 400 km, but only at 40 km, the plane must dissipate the reflected signal 10000 times less
ESR conventional fighter estimated value of the order of 10 square meters. According to our specialists, the EPR F-22 should be at the level of 0,3 square. m, that is, only in 300 times less, and not in 10000.
We will help a little dear author in arithmetic. Dividing 10 by 0,3 will give ≈30.
The detection range of a radar target depends on the generator power, antenna directional coefficient, antenna area, receiver sensitivity and target EPR
Further, using the basic radar equation, it is easy to establish that reducing the ESR by 30 times will give approximately 2,3 times the smaller detection range of “stealth” compared to a conventional fighter.
And this is already a catastrophe.
Air patrols using only the radars of the fighters themselves, irradiating a given area from many angles, greatly increase the risk of detection.
That is why in combat conditions so no one does.
Detection of airborne targets is assigned to an aircraft of long-range radar detection (AWACS), while the radar of the fighters themselves are activated only at the time of the attack.
To detect the "stealth" AWACS will be forced to go closer to the enemy. This contradicts the concept of AWACS, which should control airspace, being hundreds of kilometers away, out of range aviation the adversary.
F-22 in the hidden mode for the sake of reduced visibility should itself become almost blind and deaf. The mode of complete radio silence, the radar is turned off and hidden, even the radio signal cannot be simply accepted, because for this you need to set up at least some antennas that immediately begin to dissipate the signal. The only option is some kind of one-way satellite communication channel, when receiving devices look up into space
Everything is just like that. Fighters try not to turn on their radar, detection and targeting comes from AWACS via satellite.
On the shock F-117 radar was absent as such. In flight over the territory of the enemy, the “Night Hawk” pilot even turned off the radio altimeter. Only passive means of collecting information (radio interception, thermal imagers, GPS data).
As they say, well, well. What will happen with the EPR of the F-22 with the side or even multi-angle illumination, that there he generally has with the EPR in projections that are different from the front, then the great US state secret.
The best is kept secret by the one who does not know it, but in the case of the “Raptor” everything is written on his fuselage. Even without going into the calculations, the EPR of the F-22 and the PAK FA should be ten times lower than that of the 4 generation fighters (details in the paragraph about the parallelism of the edges and edges). In any of the selected projections.
Moreover, bearing in mind its lesser visibility, an unobtrusive fighter is much more likely to take a favorable position for an attack than a regular fighter. Go to the flank “stealth” will not be easy.
For example, H035 "Irbis", radar Su-35С. Aim with ESR 0.01 sq.m. it detects at a distance of 90 km.
The source of this data is a proven resource “Wikipedia”, and a further link to the site of NIIP. V. V. Tikhomirova confirms everything, except data on the target with the 0,01 ESR EF. m
Once the game has gone according to the rules, what prevents us from bringing data from another trusted source?
Detection of air targets depending on their EPR and distance (in nautical miles). The best characteristics among the presented radars are demonstrated by the AN / APG-77 station (Raptor fighter radar). But even she, in the opinion of the Yankees themselves, can discern a target with an 0,01 ESR apt. m at a distance of no more than 50 km. A goal with EPR 0,3 sq.m. - no more than 100 km
Finally, it should be understood that the fighter’s radar is not the “all-seeing eye” due to the limited size of the antenna, whose aperture (diameter) does not exceed one meter. What can this “baby” see when even the huge antennas of the C-400 ADMS distinguish a fighter-type target at a distance of no more than 400 km?
Maybe something and see. But advertising booklets will never tell in which sector the maximum detection range of the “Irbis” is ensured (according to one of the versions - in the field of view 17,3 ° x17,3 °, ie 300 square. Degrees). And what is the time for data accumulation for which the radar processor will be able to determine the location of the target in the selected part of the sky with a probability of 90%. But this is precisely what ultimately determines the capabilities of radar in real conditions.
Ground-based radars are not strictly limited to either the size or the number of antennas, nor the power, nor, as a result, the centimeter wavelength range. For the waves of the meter range that stealth is not stealth - everything is one.
Another appeal to the ranges of the electromagnetic spectrum with the expectation of a gullible man in the street. The joke is that absolutely all the radars that are part of the anti-aircraft missile systems (C-300 / 400, Aegis, Patriot), operate in the range of centimeter and decimeter waves.
The meter range radar has long been decommissioned, even in third world countries. The military's dislike for such radars is explicable: such a radar is not capable of forming a narrowly focused “beam” and, as a result, it has low resolution. The second incurable disease meter radar - the huge dimensions of the antenna.
The exception only confirms the general rule: the Russian Army adopted an interspecific 55ЖХNNXXМ “Sky” radar complex, which includes a module with a radar meter range (RLM-M). Alas, this complex is not intended for use as part of anti-aircraft missile systems and serves only to control air traffic.
It is worth noting that at least two radars are used as part of the air defense system. Depending on the level of those. development and the chosen method of control / guidance, an observation station is needed (sometimes multifunctional, capable of programming the autopilots of the launched missiles) and the fire control radar, which “highlights” the target. In the extreme case, the “shot and forget” scheme is used when the missile defense system is equipped with an active radar seeker, which independently “highlights” its target.
Of course, there can be no talk of any meter range radars.
The nose cone F-22 in the hidden mode should not be radiolucent, so as not to violate the geometry of the reflecting surfaces of the aircraft. But if you want to at least passively peep the radar around the air, you have to make the radome transparent, otherwise the radar, if it can emit a signal through it, will not be able to receive anything back ... Trouble ...
Trouble: dear author did not hear about frequency selective surfaces.
The only long-range missile in the F-22 armament is the AIM-120C. Its range is 50-70 km (already a dangerous distance, even in stealth mode), in the new modifications state about 100 km.
AIM-120 AMRAAM medium / long-range guided missile
The “C-7” modification has a max. 120 km launch range (adopted 11 years ago). The newer version “D” has a launch range of 180 km.
You can, of course, rest your horn and say that the engineers “Raytheon” do not understand anything about rockets. But these are the numbers that broadcast all the sources. The data given by the author about 50-70 km are related to early modifications of AMRAAM, originally from 80's.
It flies to the target "through memory", with the help of an inertial guidance system. If you do not make a radio correction, then the plane fired by such a rocket, at the time of detection of radiation by a radar (it means that someone came and probably shot out), changed the direction of the flight rather sharply so that the rocket “from memory” flew not at all to where through 40 -60 seconds (flying time AIM-120 from the maximum range) will be its target.
A two-way communication channel, like any other modern long-range air-to-air UR, fighter radar station continuously counts the target position and broadcasts corrections to the missile. The attacking fighter has nothing to fear at this moment - the enemy doesn’t have enough time to take over the radar station's work and take retaliatory measures. The attack began, the flight time of 40-60 missiles seconds.
Then the fighter radar can be turned off again. The results of the battle to the pilot will tell the operators from flying behind AWACS.
Her homing head captures the target only at a distance of 15-20 km.
And maybe not exciting. There are reasonable doubts about the effectiveness of ARGSN modern missiles against low-profile “stealth” aircraft. The miniature radar in the nose of the rocket hardly distinguishes even conventional fighters (EPR 3 ... 10 meters) at a distance of a couple of tens of kilometers. You can imagine how hard a rocket will be to find a “raptor” or a PAK FA!
Combined guidance (ARGSN + IK GOS), attempts to reduce the likelihood of a miss and take the rocket to the closest distance to the target - within hundreds of meters, from which its GOS will be guaranteed to detect the target ... Fighting stealth will require changing the usual approaches to creating rocket weapons. Headache enough for everyone.
Low visibility matters only as one of the factors when no other characteristics of the aircraft are sacrificed to it.
From the unusual appearance of dozens of polygons, the “lame dwarf” F-117 was obliged to 70's technology. The computational power of ancient computers clearly lacked the calculation of the EPR of complex surfaces of double curvature.
At present, the issue with computer equipment for calculating EPR and 3D printers, which allow manufacturing large-sized panels of complex shape, can be considered closed. LTH fighters of the fifth generation are no different from their predecessors, and in some ways even superior. The requirement of parallelism of the edges is not always effective from the point of view of aerodynamics, however, the engineers were able to compensate for this circumstance due to the greater thrust-to-weight ratio of the Raptors and PAK FA. A certain role was played by the placement of weapons in the internal bomb storage compartments, which also “ennobled” the appearance of the vehicles, reduced frontal resistance and reduced the moment of inertia of the fighters.
This is indirectly confirmed by the fact that only Americans are worn with “stealth”, while the rest of the world switched to practical work in this area only when it became possible to develop stealth aircraft without sacrificing other characteristics.
Quite a strange statement.
The Yankees were pioneers in this area: the first flight of “Have Blue” (the predecessor of the F-117) took place almost 40 years ago, in the 1977 year. To date, the fourth stealth aircraft (not counting experimental models and UAVs) is already being built overseas.
Since 2010, Russia has officially joined the stealth aircraft developers club, demonstrating the flight of its fifth-generation fighter. In fact, the development of the Russian PAK FA has been going on for 15 years, since the beginning of the 2000s.
In the back of our heads, China breathes with its crafts J-20 and J-31.
The effect of reducing conspicuity exists and is aimed at increasing the survival rate of the machine in modern combat. Above a partial reduction in visibility work even where the creation of low-profile technology was not originally planned (Su-35C, F / A-18E / F, upgraded “Silent Eagle”).
At the heart of the technology “stealth” there are no secrets and materials with unusual properties. Stealth is sound logic, multiplied by a competent calculation and supported by the power of modern technologies. Ultimately, the result of reduced conspicuity is based on the shape of the aircraft and the quality of the manufacture of its skin. In this regard, modern methods of technology “Stealth” can not cause the deterioration of the flight characteristics of aircraft.
The high cost of unobtrusive fifth-generation fighters, like the B-2 stealth bomber, is not due to stealth technology, but to the cost of developing high-tech “stuffing” for these aircraft (radar, electronics, engines).
Domestic and foreign samples of stealth technology:
Corvette Ave 20380 ("guarding")
Stealth frigate type "Lafayette", France, 1990 year
Stealth destroyer "Zamvolt"
Chengdu J-20, China