Stealth technology also known as LOT (Low Observability Technology) is a technology which covers a range of techniques used with aircraft, ships and missiles, in order to make them less visible (ideally invisible) to radar, infrared and other detection methods. The term “Stealth" is thought to have been coined in 1966 by Charles E. "Chuck" Myers, a combat pilot and later by an executive at Lockheed. 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 invisibility 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.1,3
2. HISTORY OF STEALTH AIRCRAFT
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. Jack Northrop built a flying wing in the 1940's. His plane was the first wave of stealth aircraft that actually flew. The aircraft proved to be highly unstable and hard to fly due to design flaws. The United States initially ordered 170 of these aircraft from Northrop but cancelled the order after finding that the plane had stability Flaws. Then in 1964, SR-71 the first Stealth airplane launched. It is well known as "black bird'. It is a jet black bomber with slanted surfaces. This aircraft was built to fly high and fast to be able to bypass radar by its altitude and speed. The Blackbird was developed primarily for the Cold War between the United States and the U.S.S.R. SR-71. Aircraft is shown in figure below.9,13,14
Fig 2.1 SR-71 BLACK BIRD8
Then in 1982, the first F-117A (Fig 2.2) was delivered. It is world's first operational aircraft designed to exploit low observable Stealth Technology.
Fig 2.2 F-117A NIGHT HAWK8
Then world's most advanced Stealth fighter, B-2 was delivered by 1988. A B-2 Spirit multi-role bomber is shown in figure 2.3.
Fig 2.3 B-2 SPIRIT MULTI-ROLE BOMBER8
3. HOW DOES STEALTH TECHNOLOGY WORK?
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...