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Wednesday, January 26, 2011

PowerPoint Presentation On Stealth Technology

PPT On Stealth Technology


Stealth Technology Presentation Transcript:
Stealth technology also known as LO technology (low observable technology) The concept of stealth is to operate or hide without giving enemy forces any indications as to the presence of friendly forces. This concept was first explored through camouflage by blending into the background visual clutter. A modern "stealth" vehicle will generally have been designed from the outset to have reduced or controlled signature. Varying degrees of stealth can be achieved in a particular design by the prediction of likely threat capabilities.

Stealth technology (or LO for "low observe ability") is not a single technology but It is a combination of technologies as below Radar cross section reductions Acoustics Visibility Infrared Reducing radio frequency emissions

Almost since the invention of radar, various techniques have been tried to minimize detection. Some of the techniques used for this purpose are: 1. vehicle shape 2. non-metallic airframe 3. radar absorbing material

4. Vehicle shape
Aircraft shape makes a significant difference in detectability. Another important factor is the internal construction. Behind the skin of some aircraft are structures known as re-entrant triangles. Radar waves penetrating the skin of the aircraft get trapped in these structures, bouncing off the internal faces and losing energy Stealth design must bury the engines within the wing or fuselage. Planform alignment is also often used in stealth designs which returns a radar signal in a direction away from the radar emitter.

Dielectric composites are more transparent to radar, whereas electrically conductive materials such as metals and carbon fibers reflect electromagnetic energy incident on the material's surface. Composites may also contain ferrites to optimize the dielectric and magnetic properties of the material for its application.

Radar-absorb Radar-absorbent material (RAM), often as paints, are used especially on the edges of metal surfaces. While the material and thickness of RAM coatings is classified, the material seeks to absorb radiated energy from a ground or air based radar station into the coating and convert it to heat rather than reflect it back.

Acoustic stealth plays a primary role in submarine stealth as well as for ground vehicles. Submarines have extensive usage of rubber mountings to isolate and avoid mechanical noises that could reveal locations to underwater passive sonar arrays. Early stealth observation aircraft used slow-turning propellers to avoid being heard by enemy troops below. Stealth aircraft that stay subsonic can avoid being tracked by sonic boom

The simplest stealth technology is simply camouflage; the use of paint or other materials to color and break up the lines of the vehicle or person. Most stealth aircraft use matte paint and dark colors, and operate only at night. in daylight, against the clear background of the sky, dark tones are easier to detect than light ones or as a sort of active camouflage.

An exhaust plume contributes a significant infrared signature. One means of reducing the IR signature is to have a non-circular tail pipe order to minimize the exhaust cross-sectional volume and maximize the mixing of the hot exhaust with cool ambient air. Often, cool air is deliberately injected into the exhaust flow to boost this process. Sometimes, the jet exhaust is vented above the wing surface in order to shield it from observers below. To achieve infrared stealth, the exhaust gas is cooled to the temperatures where the brightest wavelengths it radiates on are absorbed by atmospheric carbon dioxide and water vapor, dramatically reducing the infrared visibility of the exhaust plume. Another way to reduce the exhaust temperature is to circulate coolant fluids such as fuel inside the exhaust pipe, where the fuel tanks serve as heat sinks cooled by the flow of air along the wings.

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