Mahatma Gandhi Mission’sCollege of Engineering and Technology.

Noida, U.P., India

Seminar ReportOn

“STEALTH TECHNOLOGY”

As

Part of B. Tech Curriculum

Submitted By:

Name: VIVEK-BISHT Semester: 05 Roll No: 1109540043

Under the Guidance of:

Guide:- Mr. Rahul chauhan.Seminar Coordinator:- Mr.Ravindra Ram.

(Seminar Coordinator) Submitted to:- Prof. Sachin Jambhale.

Mechanical Engineering Department, MGM’s COET, Noida.

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Mahatma Gandhi Mission’sCollege of Engineering and Technology.

Noida, U.P., India

Department of Mechanical Engineering

CERTIFICATE

This is to certify that Mr. VIVEK-BISHT

of B. Tech. Mechanical Engineering, Class: TT-ME Roll No.

1109540043 has delivered seminar on the topic “STEALTH

TECHNOLOGY”. His seminar presentation and report during

the academic year as the part of B. Tech Mechanical Engineering

curriculum was poor/fair/good/excellent.

(Seminar Coordinator) (Guide) (Head of the Department)

Mr. Ravindra Ram Mr. Rahul chauhan Mr. Sachin Jambhale

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ACKNOWLEDGEMENT

I express my sincere gratitude to Prof. SACHIN JAMBHALE, Head of the Department,

Department of Mechanical Engineering, Mahatma Gandhi Mission’s college of

engineering and Technology, Noida, for his valuable suggestion, advice, guidance and

encouragement in carrying out the seminar.

I especially thank Mr. RAVINDRA RAM and Mr. RAHUL CHAUHAN, our seminar

coordinator and guide, for their guidance and help rendered for the successful completion

of my seminar and for making available the facilities of the department for the

presentation of this seminar.

I also express my gratitude to all members of staff, my parents and friends who were

very co-operative for the successful presentation of this seminar report. Last but not the

least I thank the God Almighty for his abundant grace on preparing this seminar report.

VIVEK-BISHT

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ABSTRACT

Stealth refers to the act of trying to hide or evade detection. Stealth technology is ever

increasingly becoming a paramount tool in battle especially “high technology wars” if

one may occur in the future where invincibility means invincibility. Able to strike with

impunity, stealth aircraft, missiles and warships are virtually invisible to most types of

military sensors. The experience gained at the warfront emphasizes the need to

incorporate stealth features at the design stage itself. According to conventional military

wisdom, surprise is the best form of attack. With evermore sophisticated methods of

detection, however, catching the enemy unawares has becoming increasingly difficult.

Thus paving way to the development of increasingly sophisticated technologies that help

in evading the enemy's ever vigilant “eyes”. Stealth Technology essentially deals with

designs and materials engineered for the military purpose of avoiding detection by radar

or any other electronic system. Stealth, or anti-detection, technology is applied to

vehicles (e.g., tanks, missiles, ships, and aircraft)with the goal of making the object more

difficult to detect at closer and closer ranges thus providing an element of surprise in the

attacks. Attacking with surprise gives the attacker more time to perform its mission and

exit before the defending force can counterattack. For example, If a surface to air missile

a type of antiaircraft battery defending a target observes a bomb falling and surmises that

there must be a stealth aircraft in the vicinity it is still unable to respond if it cannot get a

lock on the aircraft in order to feed guidance.

As stated earlier stealth technology can be looked upon as a perfect blend between the

engineering skills of "designing" and "technology". And for attaining stealth various

dectection techniques have to be surpassed.

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CONTENTS

TOPIC PAGE PAGE NO:

1. INTRODUCTION. 1.

2. STEALTH PRINCIPLE. 2.

3. HISTORY. 3.

4. WHAT IS STEALTH. 5.

5. RADAR. 6.

5.1. RADAR CROSS SECTION (RCS). 7.

5.2. RADAR ABSORBING MATERIAL (RAM) 8.

6. INFRARED (IR). 10.

7. VISUAL STEALTH. 11.

8. VECHICAL SHAPE. 13.

9. METHODS OF AVOIDING DETECTION. 15.

10. PLASMA STEALTH. 16.

11. DETECTION METHODS OF STEALTH AIRCRAFT. 18.

12. ADVANTAGES AND DISADVANTAGES OF STEALTH TECHNOLOGY 19.

13. STEALTH AIRCRAFT OF YESTERDAY TODAY AND TOMMOROW. 21.

14. APPLICATION. 22.

15. ADVANCED STEALTH AIRCRAFT (5th GENERATION AIRCRAFT). 23.

16. FUTURE OF STEALTH AIRCRAFT. 25.

17. FUTURE OF STRALTH AIRCRAFT-(INDIA). 28.

18. CONCLUSION 31.

19. REFERENCE 33.

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LIST OF FIGURES

Fig no TOPIC PAGE NO.

3.1 F-117A (“NIGHTHAWK”). 3

3.2 Sea shadow 4

5.1 Concept of radar cross-section. 7

5.2 Properties of RAM’s Based on angle of incidence. 8

7.1 F-117B as it Conducted almost all its mission at night. 12

8.1 F-35B. 13

8.2 B-2 (stealth bomber). 13

11.1 A very High power 3-D Radar can detect a stealth aircraft. 18

15.1 F-22 Raptor (Advanced stealth fighter). 24

15.2 F-35 Lightning. 24

16.1 Stealth helicopter (RAH-comanche). 26

16.2 BAE type 45-Destroyer. 26

16.3 X-47B (UCAV) Unmanned combat air Vechical 27

17.1 Sukhoi PAK-FA (Su50) HAL/SUKHOI. 28

17.2 INS-shivalik (stealth frigate). 29

17.3 UCAV-AURA (Concept) 30

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STEALTH TECHNOLOGY :

1.INTRODUCTION

Stealth or low observability (as it is scientifically known) is one of the most

misunderstood and misinterpreted concepts in military aviation by the common man.

Stealth aircraft are considered as invisible aircraft, which dominate the skies. With an

additional boost from Hollywood action movies, stealth is today termed as the concept

invincibility rather than invisibility. Though, the debate still continues on whether stealth

technology can make an aircraft invincible it was found that stealth aircraft are detectable

by radar.

The motive behind incorporating stealth technology in an aircraft is not just to avoid

missiles being fired at is but also to give total deniability to covert operations. This is

very much useful to strike targets where it is impossible to reach. Thus we can clearly say

that the job of a stealth aircraft pilot is not to let others know that he was ever there.

In simple terms, stealth technology allows an aircraft to be partially invisible to Radar or

any other means of detection. This doesn't allow the aircraft to be fully invisible on radar.

Stealth technology cannot make the aircraft invisible to enemy or friendly radar. All it

can do is to reduce the detection range or an aircraft. This is similar to the camouflage

tactics used by soldiers in jungle warfare. Unless the soldier comes near you, you can't

see him. Though this gives a clear and safe striking distance for the aircraft, there is still a

threat from radar systems, which can detect stealth aircraft. Stealth technology is

expanded into each of those areas which seek to detect the aircraft, ships & missiles.

Thus it is essential to develop visual, infrared acoustic and radar stealth. However many

countries have announced that they have developed counter-stealth techniques that allow

them to negate stealth.

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2.STEALTH PRINCIPLES

Stealth technology (or LO for "Low Observability") is not a single technology. It is a

combination of technologies that attempt to greatly reduce the distances at which a

vehicle can be detected; in particular radar cross section reductions, but also acoustic,

thermal, and other aspects.

Stealth technology aims at minimizing signatures and signals, and prevent/delay

detection and identification, thus increasing the efficiency of the vehicles own

countermeasures and sensors. Ben Rich, the leader of the Lockheed team that designed

the F117, pretty much sums up stealth technology when he say: “A stealth aircraft has to

be stealthy in six disciplines: radar, infrared, visual, acoustic, smoke and contrail. If you

don’t do that, you flunk the course.”

However, not all disciplines are equally important when discussing any given platform

category. Underwater warfare will naturally hand dominance to the acoustic spectrum.

However, land combat will emphasize visual, infrared and acoustic signatures. Radar and

infrared bands dominate the scene of airspace surveillance.

3.HISTORY OF STEALTH.

In the late 1930’s and 1940’s Radar technology was commonly used for dectecting

aircrafts. Since radar technology was developed during the Second World War, it should

not be surprising to learn that the first attempts at stealth technology occurred during this

period also. It might be surprising to learn, however, that it was the Germans, not the

Allies, who worked on the project. The Germans were responding to the success the

Allies were having with the early radar sets. Not only was their radar very effective at

spotting incoming enemy bombers, but it was also very important in the battle for the

Atlantic. The Germans developed a radar absorbing paint. While this ferrite-based paint

was much too heavy for aircraft, it could be used on submarines.

The United States' first stealth development was totally accidental and quickly forgotten.

Shortly after the war, Northrop Aircraft developed an experimental bomber called the

YB-49 Flying Wing. As the name implies, the aircraft had no body or tail; it was simply a

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large flying wing. The aircraft was assigned to perform a normal test flight over the

Pacific. When the test was completed, they turned and headed for home, pointing the slim

wing edge directly at the base radar station. The radar crew was shocked to see the

aircraft suddenly appear almost overhead because they had seen no evidence of it on the

radar screen. Interest in the project quickly faded after the bomber crashed in the Mojave

Desert in 1948. The plane was very unstable in flight and this stability problem was listed

as the cause of the crash. With the “cold war” and the Soviet Union well under way in the

early 1950s, it became imperative that the U.S. should learn about military developments

deep inside the country. Old bombers were converted to spy planes, but they soon proved

to be very vulnerable to attack. In order to plug this intelligence gap, a new plane was

designed. The idea was to create a plane that could cruise safely at very high altitudes,

well out of the reach of any existing fighter. The design specification required that

“consideration is given…to minimize the delectability by enemy radar.”

The task of making this plane a reality fell upon the Advanced Development Projects

team at Lockheed in California. This was a small team of highly qualified and highly

motivated engineers and pilots. This highly secret facility became known as the “Skunk

Works” and has been on the leading edge of stealth technology since the early 1950s. The

aircraft they developed became known as the U-2, and it was highly successful.

After much effort they were successful in building an aircraft that could evade the enemy

RADAR’s called the F-117A nicknamed as the “ Nighthawk ”, developed by Lockheed

Martin in 1983.

Figure 3.1:- 117A (“NIGHTHAWK”)

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There is a boat the Skunk Works developed shortly after the F-117A. It is called the "Sea

Shadow" and was built in 27 months and operated secretly in the late 1980 for $200

million dollars. The Sea Shadow was first unveiled on April 9, 1993. The barge used for

the program was the Hughes Mining Barge (HMB-1), a vessel was originally built for a

secret CIA project in the early '70s, and had been in mothballs for years. The CIA project,

it has since come out, was an attempt to recover a Soviet nuclear sub that sank off the

coast of Hawaii in 1968. The project included two ships, the Gosimir Explorer which was

basically a ship capable of deep Sea mining, and the HMB-1 which actually submerged

under the Gosimir Explorer. The HMB-1 had a claw to retrieve the USSR submarine,

which was operated by the drill on the Gossimir Explorer. (The operation was partially

successful with half of the ill-fated Soviet sub and crew being brought up from the ocean

bottom.) The Sea Shadow's stats are: Length: 160 ft. Width: 68 ft. Draft: 14.5 ft.

Displacement: 560 tons (full load).

In May 1999, the Sea Shadow was reactivated by the Navy for a 5 year program in order

to "research future ship engineering concepts and to serve as a host vessel for companies

to demonstrate advanced naval technologies." The Sea Shadow is currently operation out

of San Francisco Bay.

Figure 3.2:- SEA SHADOW

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4.WHAT IS STEALTH?

In simple terms, stealth technology allows an aircraft to be partially invisible to Radar or

any other means of detection. This doesn't allow the aircraft to be fully invisible on radar.

Stealth technology cannot make the aircraft invisible to enemy or friendly radar. All it

can do is to reduce the detection range or an aircraft. This is similar to the camouflage

tactics used by soldiers in jungle warfare. Unless the soldier comes near you, you can't

see him. Though this gives a clear and safe striking distance for the aircraft, there is still a

threat from radar systems, which can detect stealth aircraft.

The Russian 1R13 radar system is very much capable of detecting the F-117 "Night

Hawk" stealth fighter. There are also some other radar systems made in other countries,

which are capable of detecting the F-117. During the Gulf war the Iraqis were able to

detect the F-117 but failed to eliminate its threat because of lack of coordination. The

most unforgettable incident involving the detection and elimination of a stealth aircraft

was during the NATO air-war over Yugoslavia. This was done by a Russian built "not so

advanced" SAM (possibly the SA-3 or SA-6). The SAM system presumably used optical

detection for target acquisition in the case.

HOW DOES STEALTH TECHNOLOGY WORK?

The concept behind the stealth technology is very simple. As a matter of fact it is totally

the principle of reflection and absorption that makes aircraft "stealthy". Deflecting the

incoming radar waves into another direction and thus reducing the number of waves does

this, which returns to the radar. Another concept that is followed is to absorb the

incoming radar waves totally and to redirect the absorbed electromagnetic energy in

another direction. What ever may be the method used, the level of stealth an aircraft can

achieve depends totally on the design and the substance with which it is made of.

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5.RADAR.

In the early 1930's and 1940's radar technology was increasingly used to dectect aircrafts.

During the Second World War all counters Germany, Great Britain, France and The

United States of America used this technology for navigating ships and to dectect

approaching enemy aircrafts. This technology didn't pose much of a threat then as this

was not incorporated into Antiaircraft defenses then. This whole story changed during

The Vietnam and Yom Kipper wars. to make the feet more secure for use and more

effective the Americans who were the sheet anchor needed to develop an effective way to

evade radar.

RADAR (RADAR DETECTION AND RANGING):

Thus RADAR as it is abbreviated so uses radio waves for dectection of the target. Radar

basically works on two major principles.

ECHO:

Echo can be considered as a wave bouncing off a surface and coming back to the source.

This Principle can be applied for all types of waves starting from sound waves to light

waves. The time for the reception of the transmitted signal to reach the transmitter cum

receiver can be effectively used to calculate the distance of the target from the

transmitter.

THE DOPLIER SHIFT:

This being the second principle of the radar. This effect is more commonly felt for sound.

The sound that you hear as a vehicle is approaching you is at a higher pitch or a higher

frequency than the sound you hear when the vehicle is moving away from you. This

property when applied to radar can be used to determine the speed of the object. The

frequency of the reflected wave can be the same, greater or lower than the transmitted

radio wave. if the reflected wave frequency is less then this means that the target is

moving away from the transmitter and if higher then moving close to the transmitter and

if constant then the target is not moving like a helicopter hovering at a point. This can be

used to predict the speeds of the target too.

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5.1 RCS (RADAR CROSS SECTION SURFACE).

RAS or Radar absorbent surfaces are the surfaces on the aircraft, which can deflect the

incoming radar waves and reduce the detection range. RAS works due to the angles at

which the structures on the aircraft's fuselage or the fuselage itself are placed. These

structures can be anything from wings to a refueling boom on the aircraft. The extensive

use of RAS is clearly visible in the F-117 "Night Hawk". Due to the facets (as they are

called) on the fuselage, most of the incoming radar waves are reflected to another

direction. Due to these facets on the fuselage, the F-117 is a very unstable aircraft.

The concept behind the RAS is that of reflecting a light beam from a torch with a mirror.

The angle at which the reflection takes place is also more important. When we consider a

mirror being rotated from 0o to 90o, the amount of light that is reflected in the direction

of the light beam is more. At 90o, maximum amount of light that is reflected back to

same direction as the light beam's source. On the other hand when the mirror is tilted

above 90o and as it proceeds to 180o, the amount of light reflected in the same direction

decreases drastically.

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Figure 5.1:- Concept of Radar cross section

5.2RAM (RADAR ABSORBING MATERIAL).

Radar absorbent surfaces absorb the incoming radar waves rather than deflecting it in

another direction. RAS totally depends on the material with which the surface of the

aircraft is made. Though the composition of this material is a top secret. The F-117

extensively uses RAM to reduce its radar signature or its radar cross section. The RAS is

believed to be silicon based inorganic compound. This is assumed by the information that

the RAM coating on the B-2 is not water roof. This is just a supposition and may not be

true. What we know is that the RAM coating over the B-2 is placed like wrapping a cloth

over the plane. When radar sends a beam in the direction of the B-2, the radar waves are

absorbed by the plane's surface and is redirected to another direction after it is absorbed.

Figure 5.2:- Properties of RAM’s Based on angle of incidence

TYPES OF RAMs:

(i) Iron ball paint

One of the most commonly known types of RAM is iron ball paint. It contains tiny

spheres coated with carbonyl iron or ferrite. Radar waves induce molecular oscillations

from the alternating magnetic field in this paint, which leads to conversion of the radar

energy into heat. The heat is then transferred to the aircraft and dissipated. The iron

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particles in the paint are obtained by decomposition of iron pentacarbonyl and may

contain traces of carbon, oxygen and nitrogen.A related type of RAM consists of

neoprene polymer sheets with ferrite grains or carbon black particles (containing about

30% of crystalline graphite) embedded in the polymer matrix. The tiles were used on

early versions of the F-117A Nighthawk, although more recent models use painted RAM.

The painting of the F-117 is done by industrial robots with the plane covered in tiles

glued to the fuselage and the remaining gaps filled with iron ball paint. The United States

Air Force introduced a radar absorbent paint made from both ferrofluidic and non-

magnetic substances. By reducing the reflection of electromagnetic waves, this material

helps to reduce the visibility of RAM painted aircraft on radar.

(ii) Foam absorber

It is used as lining of anechoic chambers for electromagnetic radiation measurements.

This material typically consists of fireproofed urethane foam loaded with carbon black,

and cut into long pyramids. The length from base to tip of the pyramid structure is chosen

based on the lowest expected frequency and the amount of absorption required. For low

frequency damping, this distance is often 24 inches, while high frequency panels are as

short as 3-4 inches. Panels of RAM are installed with the tips pointing inward to the

chamber. Pyramidal RAM attenuates signal by two effects: scattering and absorption.

Scattering can occur both coherently, when reflected waves are in-phase but directed

away from the receiver, and incoherently where waves are picked up by the receiver but

are out of phase and thus have lower signal strength. This incoherent scattering also

occurs within the foam structure, with the suspended carbon particles promoting

destructive interference. Internal scattering can result in as much as 10dB of attenuation.

Meanwhile, the pyramid shapes are cut at angles that maximize the number of bounces a

wave makes within the structure. With each bounce, the wave loses energy to the foam

material and thus exits with lower signal strength.[4] Other foam absorbers are available

in flat sheets, using an increasing gradient of carbon loadings in different layers.

(iii) Jaumann absorber

A Jaumann absorber or Jaumann layer is a radar absorbent device. When first introduced

in 1943, the Jaumann layer consisted of two equally-spaced reflective surfaces and a

conductive ground plane. One can think of it as a generalized, multi-layered Salisbury

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screen as the principles are similar. Being a resonant absorber (i.e. it uses wave

interfering to cancel the reflected wave), the Jaumann layer is dependent upon the λ/4

spacing between the first reflective surface and the ground plane and between the two

reflective surfaces (a total of λ/4 + λ/4). Because the wave can resonate at two

frequencies, the Jaumann layer produces two absorption maxima across a band of

wavelengths (if using the two layers configuration). These absorbers must have all of the

layers parallel to each other and the ground plane that they conceal. More elaborate

Jaumann absorbers use series of dielectric surfaces that separate conductive sheets. The

conductivity of those sheets increases with proximity to the ground plane.

6.IR (INFRARED).

Another important factor that influences the stealth capability of an aircraft is the IR

(infrared) signature given out by the plane. Usually planes are visible in thermal imaging

systems because of the high temperature exhaust they give out. This is a great

disadvantage to stealth aircraft as missiles also have IR guidance system. If reducing the

radar signature of an aircraft is tough, then reducing the IR signature of the aircraft is

tougher. Engines for stealth aircraft are specifically built to have a very low IR signature.

The technology behind this is top secret like others in stealth aircraft. Another main

aspect that reduces the IR signature of a stealth aircraft is to place the engines deep into

the fuselage. This is done in stealth aircraft like the B-2, F-22 and the JSF. The IR

reduction scheme used in F-117 is very much different from the others. The engines are

placed deep within the aircraft like any stealth aircraft and at the outlet, a section of the

fuselage deflects the exhaust to another direction. This is useful for deflecting the hot

exhaust gases in another direction.

Every IR system model is composed of basic building blocks and every IR system

whether active or passive, is composed of most if not all of these building blocks. For

example, all IR systems include a source or target, a background, an atmosphere or

environment, optics and a detector. With the aid of this generalized model, the path of IR

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radiation from its sources can be analyzed, step – by – step through the various

modifications necessary for its final presentation in some form of display.

7.VISUAL STEALTH.

Historically, stealth aircrafts like the F-117 and the B-2 Spirit were painted black and

were supposed to fly only during the night time for effective camouflaging. However, the

concept of day-time stealth has been researched by Lockheed Martin, such a plane would

need to blend into the background sky and also carry antiradar and infrared stealth

technology. Researchers at the University of Florida are in the process of developing an

‘electro chromic polymer’. These thin sheets cover the aircraft’s white skin and sense the

hue, color and brightness of the surrounding sky and ground. The image received is then

projected onto the aircraft’s opposite side. When charged to a certain voltage, these

panels undergo color change. At the Tonopah test range airstrip in Nevada, another

system was tested; as claimed by a technician working at the base, an F-15 equipped with

this technology took off from the runway only to disappear from sight 3 Km away. Yet

another similar “skin” is being tested at the topsecret Groom Lake facility at Area 51 in

Nevada. It is composed of an electro-magnetically conductive polyaniline-based radar

absorbent composite material. The system also disposes photo-sensitive receptors all over

the plane that scans the surrounding area; subsequently the data is interpreted by an

onboard computer which outputs it much like a computer screen. Perhaps one day, in the

very near future, one may fly in a completely invisible aircraft. B-2 Spirit bomber,

Boeing’s Bird of Prey and the F-35 Joint Strike Fighter represent the pinnacle of modern

day advancements in this particular field of human endeavor.

1. Aircraft Camouflage

The design of camouflage for aircraft is complicated by the fact that the appearance of

the aircraft's background varies widely, depending on the location of the observer (above

or below) and the nature of the background. Many aircraft camouflage schemes of the

past used counter shading, where a light color was used underneath and darker colors

above. Other camouflage schemes acknowledge that the aircraft will be twisting and

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turning while in combat, and the camouflage pattern is applied to the entire aircraft.

Neutral and dull colors are preferred, and two or three shades selected, depending on the

size of the aircraft. Though air-to-air combat is often initialized outside of visual range, at

medium distances camouflage can make an enemy pilot hesitate until certain of the

attitude, distance and maneuver of the camouflaged aircraft. The higher speeds of modern

aircraft and the reliance on radar and missiles in air combat have reduced the value of

visual camouflage, while increasing the value of electronic "stealth" measures. Modern

paint is designed to absorb electromagnetic radiation used by radar, reducing the

signature of the aircraft, and to limit the emission of infrared light used by heat seeking

missiles to detect their target. Further advances in aircraft camouflage are being

investigated in the field of active camouflage.

Figure 7.1:- F-117b as it conducted almost all its flights at night

2. Ship Camouflage

Until the 20th century, naval weapons had a very short range, so camouflage was

unimportant for ships or the men on board them. Paint schemes were selected on the basis

of ease of maintenance or aesthetics, typically buff upperworks (with polished brass

fittings) and white or black hulls. At the turn of the century the increasing range of naval

engagements, as demonstrated by the Battle of Tsushima, prompted the introduction of

the first camouflage, in the form of some solid shade of gray overall, in the hope that

ships would fade into the mist.

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8.VECHICAL SHAPE.

The possibility of designing aircraft in such a manner as to reduce their radar cross-

section was recognized in the late 1930s, when the first radar tracking systems were

employed, and it has been known since at least the 1960s that aircraft shape makes a

significant difference in detectability. TheAvro Vulcan, a British bomber of the 1960s,

had a remarkably small appearance on radar despite its large size, and occasionally

disappeared from radar screens entirely. It is now known that it had a fortuitously stealthy

shape apart from the vertical element of the tail. In contrast, the Tupolev 95Russian long

range bomber (NATO reporting name 'Bear') appeared especially well on radar. It is now

known that propellers and jet turbine blades produce a bright radar image the Bear had

four pairs of large (5.6 meter diameter) contra-rotating propellers.

Another important factor is internal construction. Some stealth aircraft have skin that is

radar transparent or absorbing, behind which are structures termed re-entrant triangles.

Radar waves penetrating the skin get trapped in these structures, reflecting off the internal

faces and losing energy. This method was first used on the Blackbird series .

Figure 8.1:- F-35B Figure 8.2:- B-2 Stealth bomber

The most efficient way to reflect radar waves back to the emitting radar is with

orthogonal metal plates, forming a corner reflector consisting of either a dihedral (two

plates) or a trihedral (three orthogonal plates). This configuration occurs in the tail of a

conventional aircraft, where the vertical and horizontal components of the tail are set at

right angles. Stealth aircraft such as the F-117 use a different arrangement, tilting the tail

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surfaces to reduce corner reflections formed between them. A more radical method is to

eliminate the tail completely, as in the B-2 Spirit.

In addition to altering the tail, stealth design must bury the engines within

the wing or fuselage, or in some cases where stealth is applied to an extant aircraft, install

baffles in the air intakes, so that the compressor blades are not visible to radar. A stealthy

shape must be devoid of complex bumps or protrusions of any kind; meaning that

weapons, fuel tanks, and other stores must not be carried externally. Any stealthy vehicle

becomes un-stealthy when a door or hatch opens.

Planform alignment is also often used in stealth designs. Planform alignment involves

using a small number of surface orientations in the shape of the structure. For example,

on the F-22A Raptor, the leading edges of the wing and the tail surfaces are set at the

same angle. Careful inspection shows that many small structures, such as the air intake

bypass doors and the air refuelingaperture, also use the same angles. The effect of

planform alignment is to return a radar signal in a very specific direction away from the

radar emitter rather than returning a diffuse signaldetectable at many angles.

Stealth airframes sometimes display distinctive serrations on some exposed edges, such

as the engine ports. The YF-23 has such serrations on the exhaust ports. This is another

example in the use of re-entrant triangles and planform alignment, this time on the

external airframe.

Shaping requirements have strong negative influence on the aircraft's aerodynamic

properties. The F-117 has poor aerodynamics, is inherently unstable, and cannot be flown

without a fly-by-wire control system.

Similarly, coating the cockpit canopy with a thin film transparent conductor (vapor-

deposited gold or indium tin oxide) helps to reduce the aircraft's radar profile, because

radar waves would normally enter the cockpit, reflect off objects (the inside of a cockpit

has a complex shape, with a pilot helmet alone forming a sizeable return), and possibly

return to the radar, but the conductive coating creates a controlled shape that deflects the

incoming radar waves away from the radar. The coating is thin enough that it has no

adverse effect on pilot vision.

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9.METHODS OF AVOIDING DETECTION .

There are some more methods by which planes can avoid detection. These

methods do not need any hi-tech equipment to avoid detection. Some of them

have been used for years together by pilots to avoid detection.

One of the main efforts taken by designers of the stealth aircraft of today is to

carry the weapons payload of the aircraft internally. This has shown that carrying

weapons internally can considerably decrease the radar cross-section of the

aircraft. Bombs and Missiles have a tendency to reflect the incoming radar waves

to a higher extent. Providing missiles with RAM and RAS is an impossible by the

cost of these things. Thus the missiles are carried in internal bombays which are

opened only when the weapons are released.

Aircraft has used another method of avoiding detection for a very long time.

Radars can use the radar waves or electro-magnetic energy of planes radar and

locate it. An aircraft can remain undetected just by turning the radar off.

In case of some of the modern stealth aircraft, it uses its wingman in tandem to

track its target and destroy it. It is done in the following way. The fighter, which

is going to attack moves forward, the wingman (the second aircraft) on the other

hand remains at a safe distance from the target which the other fighter is

approaching. The wingman provides the other fighter with the radar location of

the enemy aircraft by a secured IFDL (In flight data link). Thus enemy radar is

only able to detect wingman while the attacking fighter approaches the enemy

without making any sharp turn. This is done not to make sudden variation in a

stealth aircraft’s radar signature.

10.PLASMA STEALTH.

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Plasma stealth technology is what can be called as "Active stealth technology" in

scientific terms. This technology was first developed by the Russians. It is a milestone in

the field of stealth technology. The technology behind this not at all new. The plasma

thrust technology was used in the Soviet / Russian space program.

Later the same engine was used to power the American Deep Space 1 probe. In plasma

stealth, the aircraft injects a stream of plasma in front of the aircraft. The plasma will

cover the entire body of the fighter and will absorb most of the electromagnetic energy of

the radar waves, thus making the aircraft difficult to detect. The same method is used in

Magneto Hydro Dynamics. Plasma stealth will be incorporated in the MiG-35 "Super

Fulcrum / Raptor Killer". This is a fighter which is an advanced derivative of the MiG-29

"Fulcrum / Baaz". Initial trials have been conducted on this technology, but most of the

results have proved to be fruitful.

When electromagnetic waves, such as radar signals, propagate into a conductive plasma,

ions and electrons are displaced as a result of the time varying electric and magnetic

fields. The wave field gives energy to the particles. The particles generally return some

fraction of the energy they have gained to the wave, but some energy may be

permanently absorbed as heat by processes like scattering or resonant acceleration, or

transferred into other wave types by mode conversion  or nonlinear effects. A plasma can,

at least in principle, absorb all the energy in an incoming wave, and this is the key to

plasma stealth. However, plasma stealth implies a substantial reduction of an aircraft's

RCS, making it more difficult (but not necessarily impossible) to detect. The mere fact of

detection of an aircraft by a radar does not guarantee an accurate targeting solution

needed to intercept the aircraft or to engage it with missiles. A reduction in RCS also

results in a proportional reduction in detection range, allowing an aircraft to get closer to

the radar before being detected.

The central issue here is frequency of the incoming signal. A plasma will simply reflect

radio waves below a certain frequency (which depends on the plasma properties). This

aids long-range communications, because low-frequency radio signals bounce between

the Earth and the ionosphere and may therefore travel long distances. Early-warning

over-the-horizon radars utilize such low-frequency radio waves. Most military airborne

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and air defense radars, however, operate in the microwave band, where many plasmas,

including the ionosphere, absorb or transmit the radiation (the use of microwave

communication between the ground and communication satellites demonstrates that at

least some frequencies can penetrate the ionosphere). Plasma surrounding an aircraft

might be able to absorb incoming radiation, and therefore prevent any signal reflection

from the metal parts of the aircraft: the aircraft would then be effectively invisible to

radar. A plasma might also be used to modify the reflected waves to confuse the

opponent's radar system: for example, frequency-shifting the reflected radiation would

frustrate Doppler filtering and might make the reflected radiation more difficult to

distinguish from noise.

Control of plasma properties is likely to be important for a functioning plasma stealth

device, and it may be necessary to dynamically adjust the plasma density, temperature or

composition, or the magnetic field, in order to effectively defeat different types of radar

systems. Radars which can flexibly change transmission frequencies might be less

susceptible to defeat by plasma stealth technology. Like LO geometry  and radar

absorbent materials , plasma stealth technology is probably not a panacea against radar.

Plasma stealth technology also faces various technical problems. For example, the plasma

itself emits EM radiation. Also, it takes some time for plasma to be re-absorbed by the

atmosphere and a trail of ionized air would be created behind the moving aircraft.

Thirdly, plasmas (like glow discharges or fluorescent lights) tend to emit a visible glow:

this is not necessarily compatible with overall low observability. Furthermore, it is likely

to be difficult to produce a radar-absorbent plasma around an entire aircraft traveling at

high speed. However, a substantial reduction of an aircraft's RCS may be achieved by

generating radar-absorbent plasma around the most reflective surfaces of the aircraft,

such as the turbojet engine fan blades, engine air intakes, and vertical stabilizers.

At least one detailed computational study exists of plasma-based radar cross section

reduction using three-dimensional computations.

11.DETECTION METHODS FOR STEALTH AIRCRAFT

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Whenever a technology is developed for military purposes, another technology is also

developed to counter that technology. There are strong efforts to develop a system that

can counter the low obervability of the fifth generation stealth aircraft. There are ways of

detection and elimination of a low observable aircraft but this doesn't give a 100%

success rageat present. On a radar screen, aircraft will have their radar cross sections with

respect to their size. This helps the radar to identify that the radar contact it has made is

an aircraft. Conventional aircraft are visible on the radar screen because of its relative

size. On the other hand, the relative size of a stealth aircraft on the radar screen will be

that of a large bird. A proven method to detect and destroy stealth aircraft is to triangulate

its location with a network of radar systems. This was done while the F-117 was shot

down during the NATO offensive over Yugoslavia. A new method of detecting low

observable aircraft is just over the horizon. Scientists have found a method to detect

stealth aircraft with the help of microwaves similar to the ones emitted by the cell phone

towers. Nothing much is known about this technology, but the US military seems to be

very keen about doing more research on this.

Figure 11.1:- A very high power 3-d radar can detect a stealth aircraft.

12.ADVANTAGES OF STEALTH TECHNOLOGY

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A smaller number of stealth vehicles may replace fleet of conventional attacks

vehicles with the same or increased combat efficiency. Possibly resulting in

longer term savings in the military budget.

A Stealth vehicles strike capability may deter potential enemies from taking

action and keep them in constant fear of strikes, since they can never know if the

attack vehicles are already underway.

The production of a stealth combat vehicles design may force an opponent to

pursue the same aim, possibly resulting in significant weakening of the

economically inferior party.

Stationing stealth vehicles in a friendly country is a powerful diplomatic gesture

as stealth vehicles incorporate high technology and military secrets.

Decreasing causality rates of the pilots and crew members.

The aircraft cannot be easily aimed by any type of surface to air missiles,

therefore there is minimum chances of hitting that aircraft.

DISADVANTAGE OF STEALTH TECHNOLOGY

Stealth technology has its own disadvantages like other technologies. Stealth

aircraft cannot fly as fast or is not maneuverable like conventional aircraft. The

F-117 nighthawk and the aircraft of its category proved this wrong up to an

extent. Though the F-117 may be fast or maneuverable or fast, it can't go beyond

Mach 2 and cannot make turns like the Su-37.

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Another serious disadvantage with the stealth aircraft is the reduced amount of

payload it can carry. As most of the payload is carried internally in a stealth

aircraft to reduce the radar signature, weapons can only occupy a less amount of

space internally. On the other hand a conventional aircraft can carry much more

payload than any stealth aircraft of its class.

Whatever may be the disadvantage a stealth vehicles can have, the biggest of all

disadvantages that it faces is its sheer cost. Stealth aircraft literally costs its

weight in gold. Fighters in service and in development for the USAF like the B-2

($2 billion), F-117 ($70 million) and the F-22 ($100 million) are the costliest

planes in the world. After the cold war, the number of B-2 bombers was reduced

sharply because of its staggering price tag and maintenance charges.

The B-2 Spirit carries a large bomb load, but it has relatively slow speed,

resulting in 18 to 24 hour long missions when it flies half way around the globe

to attack overseas targets. Therefore advance planning and receiving intelligence

in a timely manner is of paramount importance.

Stealth aircraft are vulnerable to detection immediately before, during and after

using their weaponry. since reduced RCS bombs and cruise Missiles are yet not

available; all armament must be carried internally to avoid increasing the radar

cross section. As soon as the bomb bay doors opened, the planes RCS will be

multiplied.

Another problem with incorporating "stealth" technology into an aircraft is a

wing shape that does not provide the optimum amount of lift. The resulting

increase in drag reduces flight performance. "Stealth" shapes, such as the

"faceting" found on Lockheed's F-117 "stealth" fighter, also tend to be

aerodynamically destabilizing. This is brought under control only through the use

of highly sophisticated computers that serve to electronically balance the aircraft

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in flight through its autopilot and control system. All of these modifications,

however, hurt the plane's performance, adding weight, affecting aerodynamics,

and altering the structure of the aircraft. The advantages of stealth technology

must always be weighed against its disadvantages impossible.

13.STEALTH AIRCRAFT OF YESTERDAY, TODAY AND

TOMORROW.

Stealth technology is a concept that is not at all new. During the Second World War,

allied aircraft used tin and aluminum foils in huge numbers to confuse German radar

installations. This acted as a cover for allied bombers to conduct air raids. This method

was later used as chaffs by aircrafts to dodge radar guided missiles. The first stealth

aircraft was the F-117 developed by Lockheed Martin. It was a top-secret project

developed by its Skunk Works unit. The F-117 was only revealed during the late 80s and

then saw action in the Persian Gulf. In due course of time the B-2 was developed as a

successor to the B-2. Though both of them serve different purposes, the B-2 went a step

ahead of the F-117. The B-2 was developed to deliver nuclear weapons and other guided

and unguided bombs. Another stealth aircraft, which made a lot of promises and in the

end ended up in a trashcan, was the A-12. It was a fighter that was designed to replace the

F-14 and F-18 in the future. The capabilities of this aircraft were boasted to such an

extent that the project ended up in a big mess. Stealth technology became famous with

the ATF contest. The Boeing-Lockheed YF-22 and the McDonell Douglas-Grumman

YF-23 fought for the milti-billion contract to build the fighter that would take the USAF

into the fifth generation fighter era. merica now has a competitors, Russia decided to

respond to the development of the F-22 by making the Su-47 (S-37) "Berkut" and the

MiG-35 "Super Fulcrum / Raptor Killer". These fighters were developed by the two

leading aviation firms in Russia Sukhoi and Mikhoyan Gurevich (MiG). The future of

these projects totally depends on the funding which will be provided to the Russian

defense sector. There are some hopes of increase in the funding to these projects as

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countries like India have started providing funds and technical assistance for these

projects. Another competition that soon came into the spotlight after the ATF competition

was the JSF. This time Boeing developed the X-32 and the Lockheed martinh. its X-35.

With the experience gained from developing the F-22, they were tasked with making a

replacement for the F-16. This saw great technological advances, as they had to make the

first operational supersonic VSOL aircraft. Lockheed martin took the technical assistance

of Russian scientists who developed the Yak-141. TheYak-141 is the first supersonic

VSTOL aircraft. Many projects remain over the horizon that will use stealth technology

as its primary capability. They come from some of the most unlikely contenders. These

projects include the Euro JSF, which will be designed by the team that developed the EF-

2000. Russia is stepping forward with its LFS project with the S-54 and other designs.

Two new entries into this field will be India and China. India will be introducing its

MCA, which is a twin engine fighter without vertical stabilizers.

14.APPLICATIONS.

The benefits of stealth apply not only to platforms but to a lot of weapons as well. Anti-

surface munitions like the JSOW, JASSM, Apache/SCALP/Storm Shadow,

Taurus/KEPD and many others are specifically shaped and treated to minimize their radar

and IR signatures. This has two useful payoffs: On the one hand, the weapon itself

becomes less vulnerable to enemy defensive systems, which means that fewer of the

weapons launched will be shot down before reaching their target(s). This in turn means

that fewer weapons and their parent platforms need to be allocated to any given mission,

and finally the end result is that a greater number of targets can be confidently engaged

with a given force. The other benefit is the advantage of surprise and its effect in cases

where shrinking the enemy„¢s available reaction time is of the essence. A good example

of such a situation is a typical OCA strike against an airfield. If non-stealthy strike

aircraft or stand-off weapons are used, it is quite likely that they will be detected far

enough out that the enemy will have some time available (even just 4-5 mins will do) to

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gets many of his ready-to-fly aircraft in the air and fly them somewhere else to preserve

them. If the aircraft being flushed include armed hot-pad alert fighters (a common

protective measure) these can immediately and actively contribute to the baseâ„¢s

defence against the incoming attack. Contrast this with a situation where, as a result of

using stealthy

40. weapons and/or platforms, the base is caught virtually napping and the attack is

detected so perilously close that the enemy Has no time to get anything in the air but

instead can only rely on his ground-based terminal defences. This can mean the

difference between the base suffering little or no damage and being virtually obliterated.

15.ADVANCED STEALTH AIRCRAFT OR (5 th

GENERATION AIRCRAFT).

A fifth-generation jet fighter is a fighter aircraft classification used in the United States

and elsewhere encompassing the most advanced generation of fighter aircraft as of 2013.

Fifth-generation aircraft are designed to incorporate numerous technological advances

over the fourth generation jet fighter. The exact characteristics of fifth generation jet

fighters are controversial and vague, with Lockheed Martin defining them as having all-

aspect stealth even when armed, Low Probability of Intercept Radar (LPIR), high-

performance air frames, advanced avionics features, and highly integrated computer

systems capable of networking with other elements within the theatre of war

for situational awareness. The only currently combat-ready fifth-generation fighters,

the Lockheed Martin F-22 Raptors, entered service with the U.S. Air Force in 2005.

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Figure 15.1:- F-22 RAPTOR (Advanced stealth aircraft)

Figure 15.2:- F-35 lightning

REDUCING DISADVANTAGES OF STEALTH AIRCRAFT.

Previous generation stealth aircraft, such as the B-2 Spirit and F-117 Nighthawk, were

designed to be bombers, lacking the LPI Active Electronically Scanned Array (AESA)

radars, LPI radio networks, performance, and weapons necessary to engage other

aircraft. In the early 1970s, various American design projects identified stealth, speed,

and maneuverability as key characteristics of a next generation air to air combat aircraft.

This led to the Request for Information for the Advanced Tactical Fighter which results

in the formation advance 5th generation stealth aircraft like f-22 raptor and f-35c

lightning. Later the Soviet Union outlined the need for a next-generation aircraft to

replace fourth-generation fighter aircraft.  Two projects were proposed to meet this need,

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the 4.5th generation fighter aircraft: Sukhoi Su-47 and the Mikoyan Project

1.44 (although later modernized MiG-35 to 4.5th generation fighter).

Software defined aircraft .

All revealed fifth-generation fighters use commercial off - the - shelf  main

processors to directly control all sensors to form a consolidated view of the battle

space with both onboard and networked sensors, while previous generation jet

fighters used federated systems where each sensor or pod would present its own

readings for the pilot to combine in their own mind a view of the battle space.

Advanced engines with thrust vectoring nozzle .

Fifth generation jet fighters use the newest generation of high performance jet

engines and only the American Pratt & Whitney F119 is fully developed. These

engines come with thrust vectoring nozzles. Thrust vectoring, also thrust vector

control or TVC, is the ability of an aircraft, or other vehicle to manipulate the

direction of the thrust from its engine(s) or motor in order

to control the attitude or angular velocity of the vehicle. Subsequently, it was

realized that using vectored thrust in combat situations enabled aircraft to perform

various maneuvers not available to conventional-engined planes.

To perform turns, aircraft that use no thrust vectoring must rely on aerodynamic

control surfaces only, such as ailerons or elevator; craft with vectoring must still

use control surfaces, but to a lesser extent.

Internal pay load and fuel tank.

All the missile system and fuel tank is placed internally so that radar waves will

not strike it and gets reflected back to the radar stations.

Improve aerodynamics.

More recent design techniques allow for stealthy designs such as the F-22 without

compromising aerodynamic performance. Newer stealth aircraft, like the F-22, F-

35 and the Sukhoi T-50, have performance characteristics that meet or exceed

those of current front-line jet fighters due to advances in other technologies such

as flight control systems, engines, airframe construction and materials.

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16.FUTURE OF STEALTH TECHNOLOGY.

Stealth technology is clearly the future of air combat. In the future, as air defense systems

grow more accurate and deadly, stealth technology can be a factor for a decisive by a

country over the other. In the future, stealth technology will not only be incorporated in

fighters and bombers but also in ships, helicopters, tanks and transport planes.

Figure 16.1:- Stealth helicopter (RAH-COMANCHE)

Figure 16.2:- BAE type-45 Destroyer

These are evident from theRAH-66 "Comanche" and the BAE Type-45 stealth ship. Ever

since the Wright brothers flew the first powered flight, the advancements in this

particular field of technology has seen staggering heights. Stealth technology is just one

of the advancements that we have seen. In due course of time we can see many

improvements in the field of military aviation which would one-day even make stealth

technology obsolete.

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Figure 16.3:- X-47B UCAV (Unmanned combat air vehicle)

In future stealth technology can also be applied to the  unmanned combat air

vehicle (UCAV). In these (ucav) pilots are not required for flying it instead it is

controlled by command and control system

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17.FUTURE OF STEALTH TECHNOLOGY-(INDIA).

In October 2007, India and Russia signed a pact to develop a Fifth Generation

Fighter Aircraft which is a derivative project from the PAK FA T-50. The Indian

version will be a two-seater, air superiority fighter. Another agreement was signed

between India's Hindustan Aeronautics and Russia's United Aircraft

Corporation (UAC) in December 2008 which detailed the joint development and

production the aircraft. Work on the program will start by mid-2009 and the

program is expected to be completed by 2017. Indian Air Force will get 200 twin-

seated and 50 single seated FGFAs. Sukhoi/HAL FGFA when fully developed is

intended to replace the MiG-29 Fulcrum and Mikoyan MiG-27 in the Indian

inventory.

Figure 17.1:- Sukhoi PAK-FA (SU-50) HAL/SUKHOI.

India (HAL) has also started design work on an Advanced Medium Combat

Aircraft (AMCA), which is a twin-engined 5th generation stealth multirole

fighter. It will complement the HAL Tejas, the Sukhoi/HAL FGFA, the Sukhoi

Su-30MKI and the Dassault Rafale in the Indian Air Force. The AMCA will be

designed with a very small radar cross-section and will also feature serpentine

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shaped air-intakes, internal weapons and the use of composites and other

materials. It will be a twin-engined design using the GTX Kaveri engine

with thrust vectoring with the possibility of giving the

aircraft supercruise capabilities.

The Shivalik class or Project 17 class is a class of multi-role stealth frigates in

service with the Indian Navy. They are the first stealth warships built in India.

The Shivalik class, along with the seven Project 17A frigates currently being

developed from them, are projected be the principal frigates of the Indian Navy in

the first half of the 21st century.

Figure 17.2:- INS-SHIVALIK (Stealth frigate).

DRDO of india is also developing the AURA (Autonomous Unmanned Research

Aircraft) which is an Unmanned Combat Air Vehicle (UCAV) for the Indian Air

Force. The design work on the UCAV is carried out by Aeronautical

Development Agency (ADE). The AURA UCAV will be a tactical stealth aircraft

built largely with composites, and capable of delivering laser-guided strike

weapons. The AURA will cruise at medium altitude and will be capable of

carrying two or more guided strike weapons with on-board sensors for targeting

35

and weapon guidance. The flight control system and data link packages of Aura

(unmanned combat aerial vehicle) will be designed and developed jointly by

ADA and Defense Electronic Application Laboratory.

Figure 17.3:- UCAV-AURA (Cocept)

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18.CONCLUSION.

The Detection and Stealth Technology has improved significantly more advanced in the

last fifty years or so. This trend is likely to continue as these two oppose each other. Till

date stealth aircraft have been used in several low and moderate intensity conflicts,

including operation Desert Storm. Operation Allied Force and the 2003 invasion of

Iraq .In each Case they were employed to strike high value targets which were either out

of range of conventional aircraft or which were too heavily defended for conventional

aircraft to strike without a high risk of loss. In addition, because The stealth aircraft aren’t

going to be dodging surface to air missiles and anti-aircraft artillery over the target they

can aim more carefully and thus are more likely to hit the high value targets early in the

campaign (or even for it) ,Before other aircraft had the opportunity to degrade the

opposing air defense. However, given the increasing prevalence of excellent Russion-bilt

Surface –to-air missile (SAM) system on the open market, stealth aircraft are likely to be

very important in a high intensity conflict in order to gain and maintain air supremacy.

Stealth technology .in future, would be required for clearing the way for deeper strikes ,

which conventional aircraft would find very difficult .For example ,China license-builds

a wide range of SAM systems in quantity and would be able to heavily defend important

strategic and tactical targets in the event of some kind of conflict .Even if antiradiation

weapons are used in an attempt to destroy the SAM radars of such systems, these SAMs

are capable of shooting down weapons fired against them. The surprise of a stealth attack

may become the only reasonable way of making a safe corridor for conventional

bombers. It would then be possible for the less-stealth force with superior weaponry to

suppress the remaining systems and gain air superiority. The development and the

deployment of the Visby’s- the first commissioned Stealth ships has raised new threats in

the maritime boundaries. The sudden appearance of sea clutters on the radar at a region

may be these ships. The plasma stealth technology raises new hopes of engineering

brilliance. As plasma is said to absorb all electromagnetic radiation the development of a

counter stealth technology to such a mechanism will be a strenuous task. Well to

conclude the current scenario appears something similar to the cold war both sides are

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accumulating weapons to counter each other and each side can be termed as “Stealth

Technology” and the other as “Anti-Stealth Technology”. It’s an arm race except it isn't

between specific countries. “It’s a fight between Technologies”.

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19.REFERENCE

1. http://www.totalairdominance.50megs.com/articles/stealth.htm

2. http://en.wikipedia.org/wiki/Stealth_technology

3. http://en.wikipedia.org/wiki/Radar

4. http://en.wikipedia.org/wiki/Stealth_ship

5. http://www.resonancepub.com/images/stealth_ship.gif

6. http://images.google.co.in/images

7. http://science.howstuffworks.com/question69.htm

8. http://www.espionageinfo.com/Sp-Te/Stealth-Technology.html

9. http://www.airplanedesign.info/51.htm

10. http://www.hitechweb.genezis.eu/stealth4f_soubory/image013.jpg

11. http://www.geocities.com/electrogravitics/scm.html

12. http://www.razorworks.com/enemyengaged/chguide/images/lo- reflecting.gif

13. htp://www.x20.org/library/thermal/pdm/ir_thermography.htm

14. http://en.wikipedia.org/wiki/Plasma_stealth

15. http://www.military-heat.com/43/russian-plasma

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