- Radovan, why are you stealth shot down?
- I am by chance. I did not notice him.
Where the dream of a ghostly warrior is closely intertwined with the latest achievements of progress ... The idea is simple - to strike, while remaining invulnerable to the enemy. The risk of retaliation is completely excluded. A black plane, carried away into the distance, symbolizes a convincing victory of technology over a pitiful human nature.
American bragging, the secret development of Peter Ufimtsev, the legend of the agent "Sphere" and shot down over Yugoslavia F-117. Surrealism? Elements of the stealth technology are more and more clearly appearing in the guise of modern aviation and naval technology. From Russian PAK FA and Steregushchy corvettes to American Reptors, F-35s and Zamvolt strike destroyers. The contempt in the media and the ridicule of “couch experts” do not affect the military’s opinion that they are ready to donate any means to reduce the radar and thermal visibility of military equipment. Nevertheless, the destruction of the "invisible aircraft" over the war zone with the help of the 1950s shaggy air defense system gave rise to many doubts about the effectiveness of the existing "stealth".
The opinion of society is divided.
In one camp, people are simple and gullible, holy believers, that to counter modern “stealth” old Soviet complexes and meter-range radars are enough. Have the right to do so! The Serbs knocked down the Nighthok obsolete C-125 Neva.
On the other hand - apologists of technical progress. Ardent technophyscists, convinced of the power of modern science, whose arguments are based on the ratio of the number of combat missions and the number of losses. It looks menacing and convincing.
So what is a "stealth"? In sum - an abundance of myths and legends, often very far from common sense. Interested in the topic, the author proposes to conduct a joint investigation and try to understand what the scandalous success of the “Invisible Man” is connected with.
"Stealth" (from the English. Stealth - stealth, cunning) - a set of measures to reduce the visibility of military equipment in the radio wave / infrared / acoustic / visible bands (underline) to make it more difficult to detect by the enemy. Obviously, we are not talking about complete invisibility, but only to reduce visibility. To see a bomber from a distance of 50 or 100 km - the difference is enormous.
With the effect of reducing the visibility of aircraft for enemy radar, people faced even at the dawn of the development of radar, during the Second World War. The British all-wood bomber "Moskito" was virtually invisible to the German air defense system. The Germans did not lag behind - the Horten brothers, aircraft designers, without knowing it, created a real “invisibility” - the predecessor of modern stealth. Their "epic" Ho.229 - if it appeared over the battlefield - would be a tough nut for the radar of that era.
By the 50 years, a solid theoretical base was accumulated on this issue; Scientists and aircraft designers already had a clear idea of how to reduce conspicuity. Among them - the use of various radio transparent and radio absorbing materials, the development of special forms and appearance of the aircraft.
There is no reason to doubt that the bodies are capable of absorbing radio emission - you can easily see this by putting your hand in the microwave. Ferromagnetic paints that enhance the absorption of radio waves, have been widely used in the design of the extreme drone D-21, high-altitude reconnaissance U-2, A-12 and SR-71 "Blackbird". The latter, with their special flat shape, could safely claim to be the real stealth.
Lockheed D-21 unmanned reconnaissance aircraft (1966). Ceiling 30 km, max. 3,6 speed M
But is it possible to create such a perfect machine that the radar will not see at all?
The answer was given by the Soviet physicist Peter Ufimtsev, an expert on the diffraction of radio waves on bodies of complex shape. Yes, the creation of such an aircraft is possible! The effective area of dispersion (EPR, and simply - visibility) of the aircraft is more dependent on the shape than on its size. The only problem - the appearance of an invisible aircraft will violate all the laws of aerodynamics.
F-117A at the destroyed Kuwait airbase
The monograph “The Edge Wave Method in the Physical Theory of Diffraction” became the guiding star on the way to the creation of “black airplanes.” The book released by the 6500 edition did not make a special impression on the Soviet specialists, but the mathematical apparatus described in it interested readers on the other side of the ocean. Later Petr Yakovlevich Ufimtsev will write a computer program "Echo-1", which will allow to determine the EPR of aircraft prototypes without the need to build their full-scale mock-ups and conduct difficult tests. The era of stealth has begun!
Firstborn invisible aircraft
The scandalous brainchild of Lockheed Martin, F-117 Nighthawk, and its lesser-known predecessor, the secret concept demonstrator Have Blue.
Career "Blue Bv" was short-lived - both invisible women were lost in a plane crash. "Naythoku" luckier: he was able to grow to the stage of mass production. Total - 64 aircraft, including five prototypes of the YF-117.
Lockheed have blue
Wobblin Goblin - The Lame Dwarf. A masterpiece of futurism. Stylish black plane, to the end and did not disclose their secrets. The main one is how this miracle could rise into the air ?! However, there is a guess on this score - if you invest a hundred or two billion dollars in a project, you can even get a grand piano to fly ...
While designing his first stealth, the Yankees sacrificed all the other aircraft performance characteristics to sacrifice stealth. Despite the fighter designation (F - fighter), the "Night Hawk" categorically could not conduct an air battle, and all its weapons consisted of a pair of 907-kg guided bombs. Secret bomber for secret penetration through the enemy's air defense system and performing particularly dangerous missions.
The shape was determined by the appointment. The main threat to the F-117 was ground-based air defense systems. Hence the characteristic silhouette of all the "first generation" stealth jets. Ideally smooth bottom surface and many chopped edges that form the upper side of the fuselage, oriented at angles more than 30 degrees from the vertical, because This form perfectly disperses the radiation of ground-based radar systems. Hellish "curved mirror" that reflects the rays in all directions, except the one where the radar of the enemy.
Next is the standard set of stealth technology:
- internal suspension of weapons;
- radar blockers on the engine air intakes (multi-layer metal mesh that hides the compressor blades);
- ferromagnetic paints and multilayer radar absorbing coatings - at all, without exception, even the internal, parts of the aircraft. Our specialists, who have studied the wreckage of the knocked-down Night Hawk, claim that it feels like it is entirely made of linoleum;
- facet lantern with a gold-plated electrically conductive coating, which excludes irradiation of the internal equipment of the cabin. Otherwise, the reflection from only one pilot’s helmet could be larger than from the entire aircraft;
- "sawtooth" joints of the fuselage panels and casement flaps (straight gaps are strong reflectors, therefore they are divided into many short segments);
- retractable antenna devices. During the sorties, the stealths did not have two-way communication with their command - all the aircraft’s radio equipment worked only at the reception;
- Finally, the lack of airborne radar. F-117 used only passive data collection systems: thermal imagers, GPS navigators, radio direction finders and radar detectors ... In the flights over the enemy territory, the pilots even turned off the radio altimeter. Any radiation of its own could give an "invisibility";
- other precautionary measures, in particular, the presence of other NATO planes was prohibited next to the “stealth”. There is no need to once again disturb the enemy's air defense system.
Clearly visible radar blockers on the engine air intakes
In addition to reducing the visibility in the main radio wave range, the creators of the F-117 tried to reduce the thermal background of the aircraft. Flat-shaped nozzles (for better mixing of exhaust with ambient air and speedy cooling of the jet stream) were closed with reflective shields - to prevent the engines from viewing from the lower hemisphere. The black color of the aircraft not only made it difficult to detect against the background of the night sky, but also contributed to the early dissipation of heat.
From the inside, the “black plane” refused to be surprisingly simple: the engines from the deck fighter F / A-18, the elements of the control system - from the fighter F-16. Also in the plane was used a number of nodes from the SR-71, and even from the training pair of T-33.
"INVISIBLE" was found and knocked down!
How? This topic is worthy of a separate (next) article. One has only to add that the C-125 radar systems of the air defense system hardly had anything to do with this. Insolent, confident of complete impunity, the Yankees flew at medium altitudes. The Serbs visually detected the aircraft and launched a missile using the Karat-2 television optical viewer (GRAU index 9Ш33А). This version is confirmed by the battery commander Zoltan Dani, where, according to him, they used an updated French-made viewfinder thermal imager. It does not matter. Guidance with the help of optics is one of the standard operating modes of the C-125 SAM systems when operating in a complex noise environment.
On the right - fragments F-117A. On the left - keel and flashlight downed F-16. (Belgrade Aviation Museum)
The Lame Goblin was disgraced and quietly retired. Alas, difficult to agree. Aircraft of this type were in service for a quarter of a century (1983-2008) and were regularly used in military conflicts. The Pentagon claims to be successful (thousands of enemy infrastructure destroyed). Only during the aggression against Yugoslavia, F-117A made 850 combat missions. Losses are small - just one car. At the very least, the Serbs showed only one set of Black Hawk wreckage.
If we discard speculation, the collapse of the production of "Black Hawks" (59 F-117A combat - by the standards of the US Air Force, it did not even begin to build) is due to the following reasons:
a) the specific purpose of the semi-experimental bomber;
b) the start of work on the next-generation stealth - the B-2 and the F-22 Raptor;
c) the disappearance of the main enemy - the USSR. The construction of the Night Hawks was completed in 1990 year.
Techniques to reduce visibility, implemented in the "first generation" stealth planes, were enchanting, but far from the most intelligent solutions. Contrary to the myths, the Lame Goblin did not suffer from poor handling and could even carry out such complex operations as refueling in the air. At the same time, he could not go on supersonic, could not maneuver with overloads over 6g, had an insufficient climb rate and low combat load.
Naturally, such a highly specialized "miracle" could not suit the pilots of tactical aviation. It was decided to develop the theme of the "invisible" by sacrificing something, acquiring in exchange new, excellent skills.
Thus was born the second generation STELSOV.
F-22 Raptor and PAK FA fighters, the F-35 multipurpose fighter, and countless crafts from all over the world, including the Chinese J-20, the Japanese ATD-X, the Turkish TFX, and other concepts that replicate the external the look of Russian and American fighter of the new generation.
The highest combat aviation caste is the air superiority fighter aircraft that set the standards for aerobatic flying. And awkward stealth irons, with difficulty grasping the air with crippled wing stumps. How did you manage to combine conflicting requirements in the design of these machines?
The main idea of all modern "stealth" - the parallelism of the faces and edges of the aircraft. The designers deliberately left several narrow "dangerous zones" where the signals of enemy radars were scattered, making aircraft difficult to detect from other directions. The “flattened” form of the fuselage, smoothly flowing in the plane of the wing, contributes to better dispersion of radio waves and reduces the EPR. The maximum effect of reducing the visibility of "Raptors" and PAK FA should be observed from the frontal direction. From where comes the main threat - from the approaching enemy fighter.
All ingenious is simple! The option with parallel edges allowed to achieve acceptable LTH, sufficient for effective air combat. Partial violation of aerodynamics in comparison with the ideally “clean” aerodynamic design of 4-generation fighter jets was compensated by increased thrust-to-weight ratio and the use of thrust vector controlled engines.
This is followed by a mandatory list of techniques for reducing visibility: internal weapon compartments, V-shaped tail, sawtooth joints of the casements, a gold-plated tailored cockpit lamp, S-shaped air intakes, high-quality assembly and fitting of all parts on the outer surface of the wing and fuselage, a minimum of gaps and cavity cavities, good old ferromagnetic paints and radar absorbing coatings and, of course, the ability to operate the aircraft sighting and navigation system in a completely passive mode.
Separately, the question was raised about the strategic stealth bomber B-2 "Spirit", built on a "flying wing". Another reduction in visibility, providing the maximum reduction of the EPR when the aircraft is irradiated by ground-based radar.
The “flying wing” scheme itself contains the highest meaning of aviation: the wing is the main element of the aircraft. Everything else (fuselage, keel, PGO) is superfluous ballast and, if possible, should be left on the ground. The same keel with a rudder, contrary to the opinion of the layman, is not an obligatory part of the aircraft structure: the turn in the air is due to the roll of the aircraft, due to which the lift force on the “lower” plane of the wing decreases; on the "top" - increases. The resulting moment of power and turns the car in the air. That is why the “wing load” parameter plays such an important role - the less kg per square meter. the meter surface of the wing, the more maneuvering aircraft.
As for the B-2 itself, besides the absence of the main unmasking factor, the keel, the Flying Ramp carries the full range of the aforementioned stealth technology techniques: sawtooth joints of parts, minimum gaps, radio absorbing coatings, etc.
The absence of the keel does not affect the maneuverability of the "Spirit". The only problem is stabilization: a stealth bomber is not keeping up. Which, however, does not care at all the crew of two people: automation a hundred times a second determines the position of the aircraft in space and continuously sends corrective pulses to the actuators of the control surfaces.
Stealth technology has become one of the main expenses when creating a B-2, but the abnormally high cost ($ 2 billion, including R & D and operating costs) is explained by the enormous size of the 170-ton four-engine bomber capable of continuously being in the 50 air for hours. As well as high-tech stuffing stealth aircraft: what is the cost of a single AN / APQ-181 radar with an active phased array capable of high-resolution scanning of the underlying terrain 240 km wide.
The main conclusion of a brief excursion into history stealth aircraft will become an unexpected statement that reducing visibility does not require complex and expensive solutions. At the heart of the "stealth" is logic and common sense, supported by rigorous mathematical calculations. Geometry of shapes and faces. Capricious radio-absorbing coatings that serve as the main object of criticism from haters of “black planes” are not of key importance and are an additional half-measure for reducing visibility in the centimeter range of radio waves.
And here we come close to the topic of the next article - why do domestic radars still see American "invisible"?