pravin mangilal pawar

8/4/2019 PRAVIN MANGILAL PAWAR

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Working Of Radar System Working Of Sonar System

Need Of Stealth Technology What is Stealth? What is Stealth Technology? How does Stealth Technology works? Methods to make aircraft Stealth

▪ RAS

▪ RAM



Disadvantage of Stealth Technology Stealth Technologyof yesterday,today &

tommorow List of Stealth aircraft



Stealth technology which one was used during ww-ii has manyapplications in defense.

This technology makes object invisible form Radar detection. Done either by absorbing waves or deflecting waves to any

direction coming from Radar. First,used by German,then concept captured attention of world. This tech. uses design aspect,materials for making aircaft stealth. Stealth aircraft is important in air combat. But stealth aircraft has low payload. Attempts are going on to make stealth tech. more efficient.



Principle of Operation of radar Radar is an acronym for Radio Detection and

Ranging. The term "radio"refers to the use of electromagnetic waves withwavelengths in the so-called radiowave portion of the spectrum, which covers a widerange from 104 km to 1 cm. Radarsystems typically use wavelengths on the order of 10

cm, corresponding to frequenciesof about 3 GHz. The detection and ranging part of the acronym is

accomplished by timing the delay betweentransmission of a pulse of



radio energy and its subsequentreturn. If the time delay is Dt, then the rangemay be determined by the simple

formula: R = cDt/2

where c = 3 x 108 m/s, the speed of light at whichall electromagnetic waves propagate.The factor of two in the formula comes from theobservation that the radar pulse musttravel to the target and back before detection,or twice the range.



Background During World War I, an attempt to reduce the visibility

of military aircraft resulted in the German heavybomber, the Linke-Hofmann R.I; this had a woodenstructure covered with transparent material. The firsttrue "stealth" aircraft may have been the Horten Ho229 flying wing fighter-bomber, developed inGermany during the last years of World War II[citation

needed ]

. skin was bonded together using carbon-impregnated plywood resins designed with thepurported intention of absorbing radar waves.

Later used a flying wing design for the B-2 stealthbomber.

http://en.wikipedia.org/wiki/Linke-Hofmann_R.I


http://en.wikipedia.org/wiki/Horten_Ho_229


http://en.wikipedia.org/wiki/Flying_wing




http://en.wikipedia.org/wiki/Wikipedia:Citation_needed














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

missiles being fired at is but also to give totaldeniability to covert operations. This is verymuch useful to strike targets where it isimpossible to reach. Thus we can clearly saythat the job of a stealth aircraft pilot is not tolet others know that he was ever there.



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.



Stealth or low observability (as it is scientificallyknown) is one of the most misunderstood andmisinterpreted 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 conceptinvincibility rather than invisibility. Though, thedebate still continues on whether stealth technologycan make an aircraft invincible it was found thatstealth aircraft are detectable by radar.



The metal body of an airplane is very good atreflecting radar signals, and this makes it easy to findand track airplanes with radar equipment

The goal of stealth technology is to make an airplaneinvisible 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.

http://science.howstuffworks.com/airplane.htm

http://science.howstuffworks.com/airplane.htm



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 canbe treated so they absorb radar energy aswell.

The overall result is that a stealth aircraft likean F-117A can have the radar signature of asmall bird rather than an airplane.

The only exception is when the plane banks --there will often be a moment when one of thepanels of the plane will perfectly reflect aburst of radar energy back to the antenna.



General design Materils:-

RAS(Radar Absorbent Surfaces)

RAM(Radar Absorbent Material )

RAS:RAS or Radar absorbent surfaces are the surfaceson the aircraft, which can deflect the incoming radarwaves and reduce the detection range.

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 toanother direction.



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

The angle at which the reflection takes place is also moreimportant.

When we consider a mirror being rotated from 0o to 90o,the amount of light that is reflected in the direction of thelight beam is more. At 90o, maximum amount of light thatis reflected back to same direction as the light beam'ssource. On the other hand when the mirror is tilted above

90o and as it proceeds to 180o, the amount of lightreflected in the same direction decreases drastically. This made the aircraft like F-117 stealthy.



RAM

Radar absorbent surfaces absorb the incoming radarwaves rather than deflecting it in another direction.

RAS totally depends on the material with which thesurface of the aircraft is made. Though thecomposition of this material is a top secret.

The F-117 extensively uses RAM to reduce its radarsignature or its radar cross section.

The RAM coating over the B-2 is placed like wrappinga 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



Stealth technology has its own disadvantages like othertechnologies.

Stealth aircraft cannot fly as fast or is not maneuverablelike conventional aircraft. The F-22 and the aircraft of its

category proved this wrong up to an extent. Though the F-22 may be fast or maneuverable or fast, it can't go beyondMach 2 and cannot make turns like the Su-37.

Another serious disadvantage with the stealth aircraft isthe reduced amount of payload it can carry. As most of the

payload is carried internally in a stealth aircraft to reducethe radar signature, weapons can only occupy a lessamount of space internally.

On the other hand a conventional aircraft can carry muchmore payload than any stealth

http://www.totalairdominance.50megs.com/fighters/Su-37.htm







Whatever may be the disadvantage a stealth aircraft canhave, the biggest of all disadvantages that it faces is itssheer 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 ($100million) are the costliest planes in the world. After the coldwar, the number of B-2 bombers was reduced sharplybecause of its staggering price tag and maintenancecharges. There is a possible solution for this problem. In

the recent past the Russian design firms Sukhoi andMikhoyan Gurevich (MiG) have developed fighters whichwill have a price tag similar to that of the Su-30MKI. Thiscan be a positive step to make stealth technologyaffordable for third world countries.



Stealth technology is clearly the future of air combat. Stealth technology is a concept that is not at all new.

During the Second World War, allied aircraft used tin andaluminum 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 tododge radar guided missiles.

In the future, as air defense systems grow more accurate

and deadly, stealth technology can be a factor for adecisive 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.



LIST OF STEALTH AIRCRAFT: Fully stealth designs In service

B-2 Spirit – Northrop Grumman

F-22 Raptor –

Lockheed Martin / Boeing Formerly in service F-117 Nighthawk – Lockheed Martin

Under development F-35 Lightning II – Lockheed Martin / BAE Systems / Northrop

Grumman

PAK FA – Sukhoi FGFA – Sukhoi / HAL Chengdu J-20 – Chengdu Aircraft Corporation AMCA – ADA / HAL ……..end

http://en.wikipedia.org/wiki/Northrop_Grumman_B-2_Spirit

http://en.wikipedia.org/wiki/Northrop_Grumman

http://en.wikipedia.org/wiki/Lockheed_Martin_F-22_Raptor

http://en.wikipedia.org/wiki/Lockheed_Martin

http://en.wikipedia.org/wiki/Boeing

http://en.wikipedia.org/wiki/F-117_Nighthawk



http://en.wikipedia.org/wiki/F-35_Lightning_II


http://en.wikipedia.org/wiki/BAE_Systems



http://en.wikipedia.org/wiki/PAK_FA

http://en.wikipedia.org/wiki/Sukhoi

http://en.wikipedia.org/wiki/FGFA


http://en.wikipedia.org/wiki/Hindustan_Aeronautics_Limited

http://en.wikipedia.org/wiki/Chengdu_J-20

http://en.wikipedia.org/wiki/Chengdu_Aircraft_Corporation

http://en.wikipedia.org/wiki/Advanced_Medium_Combat_Aircraft

http://en.wikipedia.org/wiki/Aeronautical_Development_Agency



http://en.wikipedia.org/wiki/Aeronautical_Development_Agency

http://en.wikipedia.org/wiki/Advanced_Medium_Combat_Aircraft

http://en.wikipedia.org/wiki/Chengdu_Aircraft_Corporation






http://en.wikipedia.org/wiki/FGFA


http://en.wikipedia.org/wiki/PAK_FA



http://en.wikipedia.org/wiki/BAE_Systems









http://en.wikipedia.org/wiki/Boeing









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