ABSTRACT Stealth aircraft are aircraft that use stealth technology to make it harder to be detected by radar and other

means than conventional aircraft by employing a combination of features to reduce visibility in the visual, audio, infrared and radio frequency (RF) spectrum. Well kno n e!amples include the "nited States# F$%%& 'ightha k (%()*s$+**)), the ,$+ Spirit -Stealth ,omber,- and the F$++ Raptor. While no aircraft is totally invisible to radar, stealth aircraft limit current conventional radar#s abilities to detect or track them effectively enough to prevent an attack. Stealth is accomplished by using a comple! design philosophy to reduce the ability of an opponent#s sensors to detect, track and attack an aircraft. .odern stealth aircraft first became possible hen a mathematician orking for /ockheed 0ircraft during the %(&*s adopted a mathematical model developed by 1etr "fimtsev, a Russian scientist, to develop a computer program called 2cho %. 2cho made it possible to predict the radar signature an aircraft made ith flat panels, called facets. 3n %(&4, engineers at /ockheed ith faceted surfaces could have a very lo radar Skunk Works found that an airplane made receiver. 5he first combat use of stealth aircraft ,arracks in Rio :ato, 1anama. as in 6ecember %()( during 7peration 8ust 9ause in

signature because the surfaces ould radiate almost all of the radar energy a ay from the

1anama. 7n 6ecember +*, %()( t o "S0F F$%%&s bombed a 1anamanian defence Force

INTRODUCTION ;Stealth<, a bu== ord common in defence circles since the early )*s, only became a mainstream reference in the nineties, after the second 1ersian >ulf War in %((%.'ight$ enhanced images of the other orldly$shapedF$%%&s taking off in the night and striking high$ value targets defences ere ith scarcely believable precision and seeming invulnerability to thick air idely televised and etched in the memories of 5? vie ers orld ide. 5he

subsequent e!posure of stealth aircraft and their participation in numerous air operations in the (*s, in combination ith the loss of at least one F$%%& in @osovo, has peeled off some of

the mythical cloak surrounding stealth. :o ever, a lot of misconceptions about the abilities and limitations of this technology still remain, even amongst people in posts of high professional responsibility. 3t is therefore useful to take a broad look at ho hat it can and hat it cannot do. 5his article stealth orks, ill e!amine strictly the application of stealth

in air assets. 6ifferent technologies and strategies for stealth are the province of land, naval and under ater forces. First of all, although it is common to discuss the principles of stealth technology (also referred to as ?/7 or ?ery /o to a narro practice applies a 7bservables technology) only as relevant band of the electromagnetic spectrum (radar emissions), stealth as a design ide range of signatures. ,en Rich, the leader of the /ockheed team that

designed the F$%%&, has statedA -0 stealth aircraft has to be stealthy in si! disciplinesA radar, infrared,visual, acoustic, smoke and contrail. 3f you don#t do that, you flunk the course.- 5hat said, not all disciplines are equally important hen discussing any given platform category. "nder ater arfare ill naturally hand dominance to the acoustic spectrum (though ill emphasi=e visual, infra$red and hen thinking onacoustic sensors can and do e!ist). /and combat

acoustic signatures. Radar and (to a lesser e!tent) infrared bands dominate the scene of airspace surveillance, and so they have to be given higher priority the applications in air arfare. ,efore discussing the various techniques of reducing the radar and infrared signature, it is useful to understand the principles of radar reflectivity and ho they can be e!ploited hen one starts thinking about aiming for stealth in earnest.

History of Stealth 3n the late %(B*Cs and %(D*Cs Radar technology Since radar technology as commonly used for detecting aircrafts. as developed during the Second World War, it should not be as the >ermans, not the 0llies, ho

surprising to learn that the first attempts at stealth technology occurred during this period also. 3t might be surprising to learn, ho ever, that it orked on the proEect. 5he >ermans ith the early radar sets. 'ot only ere responding to the success the 0llies ere having

as their radar very effective at spotting incoming enemy as much too heavy for aircraft, it as totally accidental and quickly

bombers, but it as also very important in the battle for the 0tlantic. 5he >ermans developed a radar absorbing paint. While this ferrite$based paint could be used on submarines 5he "nited States# first stealth development forgotten. Shortly after the large flying When the test ar, 'orthrop 0ircraft developed an e!perimental bomber called as assigned to perform a normal test flight over the 1acific. ing edge as shocked to see the aircraft suddenly

the F,$D( Flying Wing. 0s the name implies, the aircraft had no body or tailG it as simply a ing. 5he aircraft as completed, they turned and headed for home, pointing the slim

directly at the base radar station. 5he radar cre

appear almost overhead because they had seen no evidence of it on the radar screen. 3nterest in the proEect quickly faded after the bomber crashed in the .oEave 6esert in %(D). 5he plane as very unstable in flight and this stability problem as listed as the cause of the crash. With the ;cold country. 7ld bombers idea ar< and the Soviet "nion ell under ay in the early %(4*s, it became imperative that the ".S. should learn about military developments deep inside the ere converted to spy planes, but they soon proved to be very plane as designed. 5he ell out of the reach vulnerable to attack. 3n order to plug this intelligence gap, a ne

as to create a plane that could cruise safely at very high altitudes,

of any e!isting fighter. 5he design specification required that ;consideration is givenHto minimi=e the delectability by enemy radar.< 5he task of making this plane a reality fell upon the 0dvanced 6evelopment 1roEects team at /ockheed in 9alifornia. 5his as a small team of highly qualified and highly motivated engineers and pilots. 5his highly secret facility became kno n as the ;Skunk Works< and has been on the leading edge of stealth technology since the early %(4*s. 5he aircraft they developed became kno n as the "$+, and it highly successful. 0fter much effort they /ockheed .artin in %()B. ere successful in building an aircraft that could evade the enemy R060RCs called the F-117A nicknamed as the Nighthawk, developed by as

5here is a boat the Skunk Works developed shortly after the F$%%&0. 3t is called the -Sea Shado - and million dollars. 5he Sea Shado as first unveiled on 0pril (, %((B. 5he barge used for the program as the :ughes .ining ,arge (:.,$%), a vessel as originally built for a secret 930 proEect in the early #&*s, and had been in mothballs for years. 5he 930 proEect, it has since come out, as an attempt to recover a Soviet nuclear sub that sank off the coast of :a aii in %(J). 5he proEect included t o ships, the >osimir 2!plorer Sea mining, and the :.,$% :.,$% had a cla sub and cre hich as basically a ship capable of deep as operated by the drill on the ith half of the ill$fated Soviet hich actually submerged under the >osimir 2!plorer. 5he hich as partially successful as built in +& months and operated secretly in the late %()* for I+**

to retrieve the "SSR submarine,

>ossimir 2!plorer. (5he operation

being brought up from the ocean bottom.) 5he Sea Shado #s stats areA /engthA as reactivated by the 'avy for a 4 year program in is currently

%J* ft. WidthA J) ft. 6raftA %D.4 ft. 6isplacementA 4J* tons (full load). 3n .ay %(((, the Sea Shado order to -research future ship engineering concepts and to serve as a host vessel for companies to demonstrate advanced naval technologies.- 5he Sea Shado operation out of San Francisco ,ay.

S eden that gave us ?olvos, Saabs and 0,,0 has developed orldCs first fully operational stealth materials and use Rolls$Royce

hat it claims is the

arship that is essentially invisible to radar. 5he t o

?isby$class corvettes ill enter service by the end of the year. 5hey are made from composite ater Eets to make them electronically undetectable at more aters. 5he shipCs acoustic and than eight miles in rough seas and more than %D in calm

optical signatures are lo ered by its non$magnetic hull that, like the F$%%& 'ightha k, features large, flat surfaces and sharp angles. 5he ater Eets are %* to %4 decibels quieter than propellers. -3tCs very hard for a submarine to detect a ater Eet vessel,- 1atric :Eorth, technical manager of the S edish 6efense .ateriel 0dministration -3t has a very different signature from a propeller$driven craft as it fades into the background.-

How Does STEALTH TECHNOLOGY works?

5he concept behind the stealth technology is very simple. 0s a matter of fact it is totally the principle of reflection and absorption that makes aircrafts ; stealthy<. 6eflecting the

incoming radar this, radar

aves into another direction and thus reducing the number of

aves does

hich returns ti the radar. 0nother concept that is follo ed is to absorb the incoming aves 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 and the substance ith hich it is made of.

62529537' .25:76S 0'6 5:2 F32/6S "S26

RAS

R0S or Radar 0bsorbent surfaces are the surfaces on the aircraft, incoming radar aves and reduce the detection range. R0S

hich can deflect the hich

orks due to the angles at

the structures on the aircraftCs fuselage or the fuselage itself are placed. 5hese structures can

be anything from

ings to a refueling boom on the aircraft. 5he e!tensive use of R0S is aves are reflected to another direction. 6ue to these

clearly visible in the F$%%& ;'ight :a k<. 6ue to the facts (as they are called) on the fuselage, most of the incoming radar factes on the fuselage, the F$%%& is a very unstable aircraft. 5he concept behind the R0S is that of reflecting a light beam from a torch ith a mirror. 5he angle at hich the reflection takes place is also more important. When e consider a mirror being rotated from *o to (*o, the amount of light that is reflected in the direction of the light beam is more. 0t (*o, ma!imum amount of light that is reflected back to same direction as the light beamCs source. 7n the other hand 5his makes the aircraft like F$%%& stealthy. hen the mirror is tilted above (*o and as it proceeds to %)*o, the amount of light reflected in the same direction decreases drastically.

RA

Radar absorbent surfaces absorb the incoming radar aves rather than deflecting it in another direction. R0S totally depends on the material ith hich the surface of the aircraft is made. 5hough the composition of this material is a top secret. 5he F$%%& e!tensively uses R0. to reduce its radar signature or its radar cross section. 5he R0S is believed to be silicon based inorganic compound. 5his is assumed by the information that the R0. coating on the ,$+ is not aterproof. 5his is Eust a supposition and may not be true. What e kno is that the R0. coating over ,$+ is placed like a rapping a cloth over the plane. When radar sends a beam in the direction of the ,$+, the radar aves are absorbed by the planeCs surface and is redirected to another direction after it is absorbed. 5his reduces the radar signature of the aircraft. 5his can be done byA

,y using media ith appropriate refractive inde!. ,y using suitable optical material.

CHARACTERISTICS O! STEALTH TECHNOLOGY

5he obEect can be shaped so that any radar signals coming to it are reflected a ay from the obEect. 5he obEect can be covered in materials that absorb radar signals.

ETHODS TO A"OID DETECTION

5here are some methods by

hich planes can avoid detection. 5hese methods do not need

any hi$tech equipment to avoid detection. Some of the have been used for years together to avoid detection. Some of the most common ays are listed belo A

"se of Stealthy Shapes

"se of 0W95 (0doptive ater curtain technology) "se of Radar absorbing material

Stealthy Sha#e$

When e are using normal Shape

While e use Stealth 5echnology

A%CT &A'o#ti(e water )*rtai+ te)h+olo,y-

5his technology is a part of stealth hich is used in the ships for making lo observable. 5he ater curtain around the ship flo ing out of aves in some other direction. ater Eets either absorb or re$direct the radr

Ra'ar a.sor.i+, /aterial

ithout

reflection radar ave.

+. 5hese materials are based on 'anotechnology.

DETECTION

ETHODS

Whenever a technology is delivered for military purpose, another technology is also developed to counter that technology. 5here are strong efforts to develop a system that can counter the lo rage at present. 0 proven method to detect and destroy stealth aircraft is to triangulate its location net ork of radar systems. 5his offensive over Fugoslavia. 0 ne method of detecting lo observable aircraft is Eust over the hori=on. Scientists have ith the help of micro aves similar to the ones as done hile the F$%%& ith a observability of the fifth generation stealth aircraft. 5here are ays of detection and elimination of a lo observable aircraft but this doesnCt give a %**K success

as shot do n during the '057

found a method to detect stealth aircraft

emitted by the cell phone to ers. 'othing much is kno n about this technology, but the "S military seems to be very keen about doing more research on this.

A'(a+ta,es

Reduce the causality rate during the ar. Saving military budget. 6evelop the military secrets. ,luff the anti$detective device.

DISAD"ANTAGES

3nstability of design 2lectromagnetic emission 9ost of maintenance Sensitive skin 9ost of operations

!UTURE O! STEALTH TECHNOLOGY

Stealth technology is clearly the future of air combat. 3n the future, as air defence systems gro more accurate and deadly, stealth technology can be a factor for a decisive by a country over the other. 3n the future, stealth technology R0:$JJ ;9omanche< and the sea shado ill not only be incorporated in fighters and bombers but also in ships, helicopters, tanks and transport planes. 5hese are evident from the stealth ship. 2ver since the Wright ,rothers fle e have seen. 3n the first po ered flight, the advancements in this particular field of technology has seen staggering heights. Stealth technology is Eust one of the advancements that

due course of time

e can see many improvements in the field of military aviation

hich

ould one$day even make stealth technology obsolete.

BIBLIOGRA0HY

Wikipedia L httpAMMen. ikipedia.orgM ikiMStealthtecnology

3mages from httpAMMimages.>oogle.co.in

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