Stealth
In recent times the term "Stealth" is increasingly associated with the fighters, bombers and ships of last generation, often based only on a fact "aesthetic" rather than a scientific analysis. It should immediately debunked the concept of "invisibility": nothing is invisible, nor will ever be possible (through current technology) to create a veivolo, medium or carrier which could not be detected by radar. This article will be exposed the foundations and principles of this technology through a physical and engineering point of view.
To understand the Stealth technology we must start from the radar operating bases: the electromagnetic waves produced by the radar, reached an obstacle are reflected back to the unit and then processed; the processed signal is used to determine the location, size and direction of the object.
Section Radar
The RCS is the measure of how much an object (not just aircraft) looms large on the radar screen: more big is the RCS of an object, the more likely they are to be detected by radar. For example, an F22 or B2 have an RCS of 0.0001 m², in practice they are invisibii the majority of today's radar. Here is a sample chart comparing vehicles, aircraft and boats.
In recent times the term "Stealth" is increasingly associated with the fighters, bombers and ships of last generation, often based only on a fact "aesthetic" rather than a scientific analysis. It should immediately debunked the concept of "invisibility": nothing is invisible, nor will ever be possible (through current technology) to create a veivolo, medium or carrier which could not be detected by radar. This article will be exposed the foundations and principles of this technology through a physical and engineering point of view.
To understand the Stealth technology we must start from the radar operating bases: the electromagnetic waves produced by the radar, reached an obstacle are reflected back to the unit and then processed; the processed signal is used to determine the location, size and direction of the object.
Section Radar
The RCS is the measure of how much an object (not just aircraft) looms large on the radar screen: more big is the RCS of an object, the more likely they are to be detected by radar. For example, an F22 or B2 have an RCS of 0.0001 m², in practice they are invisibii the majority of today's radar. Here is a sample chart comparing vehicles, aircraft and boats.
The low value of RCS of some particular aircraft (or terrestrial / vessels) should not suggest total invisibility of the latter. A modern radar will certainly have difficulties in intercepting stealth aircraft at long distances but could easily be able to locate it at shorter distances: with stealth technology may be identified in 10-20 km but not at 150-200km as happens for non-stealth objects . And 'possible to make a comparison with a small insect: with our eyes we can glimpse up close, being able to hear with your ears, but we will have difficulty in following him with his eyes because of its size and its speed.
Stealth Technology works on the principle of eliminating the radar reflections by:
a) Absorbing the airwaves (RAM Coating)
b) Divert radio waves (Surface Modeling)
Absorption of Radio Waves
The absorption of radio wave technology is primarily via the RAM (Radio Absorbent Material): the mechanism is so secret that even today at a distance of decades we know little or nothing of the SR 71 RAM system (one of the first stealth aircraft built by Lockheed) and this suggests that this technology is important for years to come. For what it is possible to understand, the absorption occurs through the energy conversion of radio waves into heat which is dissipated on the plane surface.