Stealth Seminar
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US Air Force fighter jets have been crisscrossing over international routes in Mumbai airspace, without forwarding the flight plan to the Mumbai Air Traffic Control (ATC). The aircraft, mainly bombers, cannot be detected by ATC radar. What this means is that these jets have come perilously close to passenger aircraft, narrowly escaping collision. Nearly 10 international routes into south and east Africa use this flight path, which sees around 40 flights every day. “The US jets do not submit any flight plan and are undetected by radar. It’s a major accident waiting to happen if any of these supersonic jets collide with a civilian aircraft,” said a senior air traffic official from New Delhi. http://web.mid-day.com/1news/city/2006/may/136722.htm Well....the Aircrafts being mentioned here are based on "STEALTH TECHNOLOGY", which makes an aircraft almost 'invisible ' to the Radar.... This was also my Seminar topic in my college...so here are some Stealth Technology facts... 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. Most conventional aircraft have a rounded shape. This shape makes them aerodynamic, but it also creates a very efficient radar reflector. The round shape means that no matter where the radar signal hits the plane, some of the signal gets reflected back:
A stealth aircraft, on the other hand, is made up of completely flat surfaces and very sharp edges. When a radar signal hits a stealth plane, the signal reflects away at an angle, like this:
In addition, surfaces on a stealth aircraft can be treated so they absorb radar energy as well. The overall result is that a stealth aircraft like an F-117A can have the radar signature of a small bird rather than an airplane. The only exception is when the plane banks -- there will often be a moment when one of the panels of the plane will perfectly reflect a burst of radar energy back to the antenna. USE OF RADAR ABSORBENT MATERIAL (RAM) RAM (radar absorbent material) coating, especially on the edges of metal surfaces. The RAM coating, known also as iron ball paint, contains tiny spheres coated with carbonyl iron ferrite. Radar waves induce alternating magnetic field in this material, which leads to conversion of their energy into heat. Early versions of F-117A planes were covered with neoprene-like tiles with ferrite grains embedded in the polymer matrix, current models have RAM paint applied directly. The aircraft must be painted by robots, not just because the solvent used is toxic, but because the thickness of the sprayed layers must be tightly controlled.
In a similar vein, it is known that coating the cockpit window with a thin film of gold helps to reduce the aircraft's radar profile because radar waves would normally enter the cockpit, bounce off something random (the inside of the cockpit has a very complex shape), and possibly return to the radar - but if the gold reflects the incoming radar waves, most of the energy is likely to go straight up rather than back to the radar. The gold film is thin enough that it doesn't significantly affect the pilot's vision. Technologies to reduce other signatures such as infra-red, visible, and sonic. Stealth aircraft need to stay subsonic to avoid being tracked by sonic boom. Some early stealth observation aircraft utilised very slow-turning propellers in order to be able to orbit above enemy troops without being heard. Most stealth aircraft use matte paint and dark colors, and operate only at night. Lately, interest on daylight Stealth (specially by the USAF) has emphasized the use of gray paint in disruptive schemes, and it is assumed that some sort of lighting could be used in the future to mask shadows in the airframe (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. The B-2 has wing tanks for a contrail-inhibiting chemical, alleged by some to be chlorofluorosulphonic acid[2], and mission planning also considers altitudes where the probability of their formation is minimized. The primary means of reducing the infrared signature is generally to have a non-circular tail pipe (a slit shape) in order to minimise the exhaust area and maximise 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. [3] Technologies to reduce radar emissions. Infrared emissions and sound aren't the only detectable emissions generated by ships or aircraft. The stealth vehicle must not radiate any energy which can be detected by the enemy, such as that of a height finding radar, terrain following radar or search radar. The F-117 uses passive infra-red and "low light level TV" sensor systems to aim its weapons and the F-22 has an advanced LPI radar which can illuminate enemy aircraft without triggering a radar warning receiver response. INDIA IN THE STEALTH RACE : No Indian Aircraft have the Stealth capabilities as of now, however Indian Navy recently acquired INS Talwar which incorporates some Stealth Features which help it reduce its RCS to a significant level.
The ship's redesigned topside & hull has considerably reduced radar cross-section and this feature alone, clearly separates the Project 1135.6 from its predecessors. While the superstructure sides are sloped and relatively clean, the very cluttered topside of the ship cannot be remotely described as having any signature reducing features. However, these frigates will be the first Indian Navy warships to incorporate some stealth features and a vertical launch missile system. The ship's hull is characterised by outward flare and tumblehome, while the superstructure (which forms a continuous junction with the hull) has a large fixed tumblehome angle. This feature of INS Talwar makes it very easy to diffrentiate it from the conventional war ships... Here is how INS Delhi looks in comparision to INS Talwaar.... INS Delhi Stealth is clearly the future of air combat. In the future, as air defense capabilities grow more accurate and deadly, stealth can be a factor for a decisive victory by one country over an other. In the future, stealth will not only be incorporated in fighters and bombers but also in ships, helicopters, tanks and transport planes. Ever since the Wright brothers flew the first powered flight, the advancements in this particular field of human endeavor has seen staggering heights. Stealth is just one of the advancements that we have seen. In due course of time we will see many improvements in the field of aviation which could one-day even make stealth obsolete !
Stealth Fighter - Paper Presentation Stealth means 'low 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 `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. 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. 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 orders 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.
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 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.
Title: Authors: Keywords: Issue Date: Publisher: Citation:
Abstract:
Stealth Technology Akhila,K Stealth Technique Radar and IR Plasma stealth Stealth aircrafts Nov-2006 Sree Narayana Gurukulam College of Engineering Department of Electrical and Electronics Engineering Stealth is the technique of making a plane (or any other object) less visible to the enemy by reducing its radar and IR (infra red, heat) visibility. Reducing the IR image of a plane can be accomplished by directing the hot exhaust gasses to the top of the plane and mix them with cold air (the B-2 uses this technique). Reducing radar visibility can be accomplied by deflecting the radar waves in such a direction that they don't go back to the emitting radar (F-117 uses faceting, the B-2 uses continues curving) or making use of less radar reflecting materials (composite material, plastic) and/or radar absorbing coatings.A study of radar absorbing materials is also made. The seminar also deals with plasma stealth technology http://hdl.handle.net/123456789/610
URI: Appears in Seminar Reports Collections:
A stealth aircraft, on the other hand, is made up of completely flat surfaces and very sharp edges. When a radar signal hits a stealth plane, the signal reflects away at an angle, like this:
In addition, surfaces on a stealth aircraft can be treated so they absorb radar energy as well. The overall result is that a stealth aircraft like an F-117A can have the radar signature of a small bird rather than an airplane. The only exception is when the plane banks -- there will often be a moment when one of the panels of the plane will perfectly reflect a burst of radar energy back to the antenna. USE OF RADAR ABSORBENT MATERIAL (RAM) RAM (radar absorbent material) coating, especially on the edges of metal surfaces. The RAM coating, known also as iron ball paint, contains tiny spheres coated with carbonyl iron ferrite. Radar waves induce alternating magnetic field in this material, which leads to conversion of their energy into heat. Early versions of F-117A planes were covered with neoprene-like tiles with ferrite grains embedded in the polymer matrix, current models have RAM paint applied directly. The aircraft must be painted by robots, not just because the solvent used is toxic, but because the thickness of the sprayed layers must be tightly controlled.
In a similar vein, it is known that coating the cockpit window with a thin film of gold helps to reduce the aircraft's radar profile because radar waves would normally enter the cockpit, bounce off something random (the inside of the cockpit has a very complex shape), and possibly return to the radar - but if the gold reflects the incoming radar waves, most of the energy is likely to go straight up rather than back to the radar. The gold film is thin enough that it doesn't significantly affect the pilot's vision. Technologies to reduce other signatures such as infra-red, visible, and sonic. Stealth aircraft need to stay subsonic to avoid being tracked by sonic boom. Some early stealth observation aircraft utilised very slow-turning propellers in order to be able to orbit above enemy troops without being heard. Most stealth aircraft use matte paint and dark colors, and operate only at night. Lately, interest on daylight Stealth (specially by the USAF) has emphasized the use of gray paint in disruptive schemes, and it is assumed that some sort of lighting could be used in the future to mask shadows in the airframe (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. The B-2 has wing tanks for a contrail-inhibiting chemical, alleged by some to be chlorofluorosulphonic acid[2], and mission planning also considers altitudes where the probability of their formation is minimized. The primary means of reducing the infrared signature is generally to have a non-circular tail pipe (a slit shape) in order to minimise the exhaust area and maximise 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. [3] Technologies to reduce radar emissions. Infrared emissions and sound aren't the only detectable emissions generated by ships or aircraft. The stealth vehicle must not radiate any energy which can be detected by the enemy, such as that of a height finding radar, terrain following radar or search radar. The F-117 uses passive infra-red and "low light level TV" sensor systems to aim its weapons and the F-22 has an advanced LPI radar which can illuminate enemy aircraft without triggering a radar warning receiver response. INDIA IN THE STEALTH RACE : No Indian Aircraft have the Stealth capabilities as of now, however Indian Navy recently acquired INS Talwar which incorporates some Stealth Features which help it reduce its RCS to a significant level.
The ship's redesigned topside & hull has considerably reduced radar cross-section and this feature alone, clearly separates the Project 1135.6 from its predecessors. While the superstructure sides are sloped and relatively clean, the very cluttered topside of the ship cannot be remotely described as having any signature reducing features. However, these frigates will be the first Indian Navy warships to incorporate some stealth features and a vertical launch missile system. The ship's hull is characterised by outward flare and tumblehome, while the superstructure (which forms a continuous junction with the hull) has a large fixed tumblehome angle. This feature of INS Talwar makes it very easy to diffrentiate it from the conventional war ships... Here is how INS Delhi looks in comparision to INS Talwaar.... INS Delhi Stealth is clearly the future of air combat. In the future, as air defense capabilities grow more accurate and deadly, stealth can be a factor for a decisive victory by one country over an other. In the future, stealth will not only be incorporated in fighters and bombers but also in ships, helicopters, tanks and transport planes. Ever since the Wright brothers flew the first powered flight, the advancements in this particular field of human endeavor has seen staggering heights. Stealth is just one of the advancements that we have seen. In due course of time we will see many improvements in the field of aviation which could one-day even make stealth obsolete !
Stealth Fighter - Paper Presentation Stealth means 'low 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 `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. 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. 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 orders 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.
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 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.
Title: Authors: Keywords: Issue Date: Publisher: Citation:
Abstract:
Stealth Technology Akhila,K Stealth Technique Radar and IR Plasma stealth Stealth aircrafts Nov-2006 Sree Narayana Gurukulam College of Engineering Department of Electrical and Electronics Engineering Stealth is the technique of making a plane (or any other object) less visible to the enemy by reducing its radar and IR (infra red, heat) visibility. Reducing the IR image of a plane can be accomplished by directing the hot exhaust gasses to the top of the plane and mix them with cold air (the B-2 uses this technique). Reducing radar visibility can be accomplied by deflecting the radar waves in such a direction that they don't go back to the emitting radar (F-117 uses faceting, the B-2 uses continues curving) or making use of less radar reflecting materials (composite material, plastic) and/or radar absorbing coatings.A study of radar absorbing materials is also made. The seminar also deals with plasma stealth technology http://hdl.handle.net/123456789/610
URI: Appears in Seminar Reports Collections:
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