Stealth means now observable. The very basic idea of Stealth Technology in the military is to 'blend' in with the background. The quest for a stealthy plane actually began more than 50 years ago during World War II when RADAR was first used as an early warning system against fleets of bombers. As a result of that quest, the Stealth Technology evolved. Stealth Technology is used in the construction of mobile military systems such as aircrafts and ships to significantly reduce their detection by enemy, primarily by an enemy RADAR. The way most airplane identification works is by constantly bombarding airspace with a RADAR signal. When a plane flies into the path of the RADAR, a signal bounces back to a sensor that determines the size and location of the plane.

Other methods focus on measuring acoustic (sound) disturbances, visual contact, and infrared (heat) signatures. Stealth technologies work by reducing or eliminating these telltale signals. Panels on planes are angled so that radar is scattered and no signal returns. Planes are also covered in a layer of absorbent materials that reduce any other signature the plane might leave. Shape also has a lot to do with the * invisibility1 of stealth planes. Extreme aerodynamics keeps air turbulence to a minimum and cut down on flying noise. Special low-noise engines are contained inside the body of the plane. Hot fumes are then capable of being mixed with cool air before leaving the plane.

This fools heat sensors on the ground. This also keeps heat-seeking missiles from getting any sort of a lock on their targets. Stealth properties give it the unique ability to penetrate an enemy's most sophisticated defenses and threaten its most valued and heavily defended targets. At a cost of $2 billion each, stealth bombers are not yet available worldwide, but military forces around the world will soon begin to attempt to mimic some of the key features of stealth planes, making the skies much more dangerous.

With the increasing use of early warning detection devices such as radar by militaries around the world in the 1930's the United States began to research and develop aircraft that would be undetectable to radar detection systems. The first documented stealth prototype was built out of two layers of plywood glued together with a core of glue and sawdust. This prototype's surface was coated with charcoal to absorb radar signals from being reflected back to the source, which is how radar detection systems detect items in the air.

The idea is for the radar antenna to send out a burst of radio energy, which is then reflected back by any object it happens to encounter. The radar antenna measures the time it takes for the reflection to arrive, and with that information can tell how far away the object is.

The metal body of an airplane is very good at reflecting radar signals, and this makes it easy to find and track airplanes with radar equipment.

The goal of stealth technology is to make an airplane invisible to radar. There are two different ways to create invisibility:

> The airplane can be shaped so that any radar signals it reflects are reflected away from the radar equipment.

> The airplane can be covered in materials that absorb radar signals.

RADAR

Currently the way to detect and even identify an aircraft is the use of RADAR (radio detection and ranging). This system invented during World War II, simply works by constantly sending bursts of radio waves of certain frequencies and measures the echoes of each burst. Objects are reflecting parts of the energy of radio waves. Depending on the material the object is made of, this echo is stronger or weaker, but there is an echo. By measuring the reflected energy as a function of position and time, computers can calculate what it is that reflects the energy, where it is in 3D space and also in what direction it moves. To get a proper overview of an area with RADAR, the transmitting and receiving antenna should rotate in angles of 360 degrees. RADAR works on.