mechanical aspects in stealth technology

Stealth Technology

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STEALTH TECHNOLOGYPresented By BIPIN KUMAR JHA TEME A-30

Mechanical Aspects In

Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

Stealth is a technique in which we can make any object partially invisible.Stealth is an important technology which used in military operations.Stealth technologyalso known asLO Technology (Low Observable Technology).INTRODUCTION

What is Stealth Technology ?Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

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, 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. Whatever 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. 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.

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HISTORY

The first Stealth" aircraft have been developed in Germany during the last years of World War- II.

This technique has also used in ships.

Later Americans worked on stealth technology and succeeded.


In England, irregular units of gamekeepers in the 17th century were the first to adopt drab colours (common in the 16th century Irish units) as a form of camouflage, following examples from the continent. Yehudi lights were successfully employed in World War II by RAF Shorts Sunderland aircraft in attacks on U-boats. In 1945 a Grumman Avenger with Yehudi lights got within 3,000 yards (2,700 m) of a ship before being sighted. This ability was rendered obsolete by the radar of the time. The U-boat U-480 may have been the first stealth submarine. It featured a rubber coating, one layer of which contained circular air pockets to defeat ASDIC sonar. One of the earliest stealth aircraft seems to have been the Horten Ho 229 flying wing. It included carbon powder in the glue to absorb radio waves. Some prototypes were built, but it was never used in action. During the 1950s, the Avro Vulcan, a British bomber, had a remarkably small appearance on radar despite its large size, and occasionally disappeared from radar screens entirely. In 1958, the CIA requested funding for a reconnaissance aircraft, to replace U-2 spy planes in which Lockheed secured contractual rights to produce the aircraft. "Kelly" Johnson and his team at Lockheed's Skunk Works were assigned to produce the A-12 or OXCART the first of the former top secret classified Blackbird series which operated at high altitude of 70,000 to 80,000 ft and speed of Mach 3.2 to avoid radar detection. Radar absorbent material had already been introduced on U-2 spy planes, and various plane shapes had been developed in earlier prototypes named A1 to A11 to reduce its detection from radar. Later in 1964, using prior models, an optimal plane shape taking into account compactness was developed where another "Blackbird", the SR-71, was produced, surpassing prior models in both altitude of 90,000 ft and speed of Mach 3.3. The Lockheed SR-71 included a number of stealthy features, notably its canted vertical stabilizers, the use of composite materials in key locations, and the overall finish in radar absorbing paint. During 1970s, the U.S. Department of Defence then launched a project called Have Blue to develop a stealth fighter. Bidding between both Lockheed and Northrop for the tender was fierce to secure the multi-billion dollar contract. Lockheed incorporated in its program paper written by a Soviet/Russian physicist Pyotr Ufimtsev in 1962 titled Method of Edge Waves in the Physical Theory of Diffraction, Soviet Radio, Moscow, 1962. In 1971 this book was translated into English with the same title by U.S. Air Force, Foreign Technology Division (National Air Intelligence Center ), Wright-Patterson AFB, OH, 1971. Technical Report AD 733203, Defense Technical Information Center of USA, Cameron Station, Alexandria, VA, 22304-6145, USA. This theory played a critical role in the design of American stealth-aircraft F-117 and B-2. The paper was able to find whether a plane's shape design would minimise its detection by radar or its radar cross-section (RCS) using a series of equations could be used to evaluate the radar cross section of any shape. Lockheed used it to design a shape they called the Hopeless Diamond, securing contractual rights to mass produce the F-117 Nighthawk. The F-117 project began with a model called "The Hopeless Diamond" (a wordplay on the Hope Diamond) in 1975 due to its bizarre appearance. In 1977 Lockheed produced two 60% scale models under the Have Blue contract. The Have Blue program was a stealth technology demonstrator that lasted from 1976 to 1979. The success of Have Blue lead the Air Force to create the Senior Trend program which developed the F-117. 5

The F-117A Nighthawk Stealth Fighter, a single seat, twin engine aircraft developed by Lockheed Martin, was the first aircraft designed to exploit low-observable stealth technology.


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. Bipin Kumar Jha

RADARRADAR is the acronym for Radio Detection And RangingRadar is an object-detection system that uses radio waves to determine the range, altitude, direction, or speed of objectsRadar is something that is in use all around us, although it (radio waves) is normally invisible.Air Traffic Control uses radar to trackplanes both on the ground and in the air, and also to guide planes for smooth landings.NASA uses radar to map the Earth and other planets, to track satellitesand space debris and to help with things like docking and manoeuvring.The military uses it to detect the enemy and to guide weapons.


When people use radar, they are usually trying to accomplish one or all of the following three things:

Detect the presence of an object situated at some distanceDetect the speed of an objectTo map or locate something

All three of these objectives can be accomplished using: ECHO DOPPLER SHIFTMechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

ECHOEchois something you experience all the time. If you shout into a well or a canyon, the echo comes back a moment later.

The echo occurs because some of the sound waves in your shout reflect off of a surface (either the water or canyon wall) and travel back to your ears.

The length of time between the moment you shout and the moment that you hear the echo is determined by the distance between you and the surface that creates the echo.Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

DOPPLER shiftDoppler shift occurs when sound is generated by, or reflected off of, a moving object. Let's say there is a car coming toward you at 60 miles per hour (mph) and its horn is blaring. You will hear the horn playing one "note" as the car approaches, but when the car passes you the sound of the horn will suddenly shift to a lower note.It's the same horn making the same sound the whole time. The change you hear is caused by Doppler shift.Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

how radar works??The radar dish or antenna transmits pulses of radio waves or microwaves that bounce off any object in their path. The object returns a tiny part of the wave's energy to a dish or antenna that is usually located at the same site as the transmitter.



How To Make Things Invisible ?The goal ofstealth technologyis to make an airplane invisible to radar. There are two different ways to create invisibility: The airplane can be Shaped (Design) 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 (also called as Radar Absorbing Materials RAM). Apart from these things, the manufacturer should also consider the following.


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Principle OF STEALTH TechnologyInfrared detection.Visual detection.Acoustic detection.Radar detection. Reduction in these detection is the principle of stealth technology. Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

RADAR CROSS-SECTION REDUCTIONS

Almost since the invention of radar, various techniques have been tried to minimize detection.Some of the techniques used for this purpose are:Vehicle Shape & Design, andRadar Absorbing Material (RAM)Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

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:Difference Between Conventional & Stealth Aircraft DesignMechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

STEALTH VECHICLE SHAPES & DESIGN It should be coated with the Radar Absorbing Materials. Its tail should kept an ACUTE angle. Planes wings has to kept at Angle. Design of Nose. Stealth aircraft must bury the Engines within the wing or fuselage.

A corner reflector is a retro reflector consisting of three mutually perpendicular, intersecting flat surfaces, which reflects electromagnetic waves back towards the source.


What is Radar Absorbing Materials (RAM)?RAM is a class of materials used in stealth technology to disguise vehicle or structure from radar detection.RAM reduces the radar cross section making the object appear smaller.These materials are both very heavy and very costly, two key limitations to their adoption for many applications.MaterialsCarbon fiber compositesMagnetic Ferrite-based substance


The material that is used to paint the stealth can be made of special materials like carbon powder in the glue or silicon based inorganic compound that would the waves that fall on the plane.Dielectric materials are used as they are transparent to radar waves.Composites of ferrites are used to optimize dielectric and magnetic properties


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Reducing Infrared signature

Infrared radiation are emitted by all matter above absolute zero temperature. Hot materials, such as engine exhaust gasses or wing surfaces heated by friction with the air, emit more infrared radiations than cooler material.Embedding jet engines inside the wings is one basic design step towards infrared stealth.Other measures include extra shielding of hotter parts, mixing of cooler air with hot exhausts before emission etc.


Reducing acoustic signatureThe engines of the stealth planes should be designed such that the noise emitted by them is minimum.Engines should be placed deep inside the plane.Slow turning propellers were used to minimize the noise in earlier designs to avoid detection by enemy troops. Incorporating acoustic-stealth measures, including sound-absorbent linings inside its engine intake and exhaust cowlings.Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

Limitations of stealth1. Instability of design2. Aerodynamic limitations3. Reduced payload4. Cost of maintenance5. Sensitive skin6. Cost of operations


Advantages of stealth1. Reduce the casualty rate during the war.2. Develop the military secretes.3. Bluff the anti-detective device .4.Lesser number of stealth aircrafts required. 5. We can perform spy mission.6. Can be used in Civil aviation.


Stealth HelicopterNewest addition in stealth technology.Designs for blades have emerged that can significantlyreduce noise.Used for raid on the compound ofOsama bin Ladenon May 2, 2011.Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

Northrop Grumman B-2 SpiritParticularStrategic Stealth BomberNational originU.S.AManufacturerNorthrop Grumman CorporationFirst flight17 July 1989Introduction April 1997Status In servicePrimary userUnited states air forceProduced 1988-2000Number built21Unit cost$737 million


B 2 spiritMax speed= Mach 0.95Range = 11,100 kmService Ceiling= 15,200 kmThrust/Weight = 0.205

National origin : U.S.AMechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

BIPIN KUMAR JHA (BKJ) - 1 Mach Speed = 1224 kph1 Kph speed= 0.000816993 MachLockheed martin F 22 raptorRole Stealth air superiority fighterNational originU.S.AManufacturer Lockheed MartinFirst flight7 Sep. 1997Introduction 15 Dec. 2005Status In servicePrimary user U.S air forceProduced 1996-2011Number built195Unit cost$150 million


F 22 raptor


F-35lightning iiRole Stealth multirole fighterNational originU.S.AManufacturerLockheed Martin First flight 15 DEC 2006IntroductionDec 2015StatusIn initial production and testing, used for training by U.S Primary usersU.S air forceProduced2006- presentNumber built100 as of 2013Unit cost$252.3 million


Indias step towards stealthHAL : LIGHT COMBAT HELICOPTER (LCH)Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

HAL LIGHT COMBAT HELICOPTERRole Attack helicopterNational originIndiaManufacturerHindustan Aeronautics LimitedFirst flight29 march 2010StatusDevelopment trialsPrimary usersIndian ArmyIndian Air ForceProduced2010-presentNumber built3Unit cost$17.48 million

General characteristics Crew: 2 Length: 15.8 m Rotor diameter: 13.3 m Height: 4.7 m Disc area: 138.9 m Max. take off weight: 5,800 kg Power plant : 2 HAL/Turbo meca Shakti turbo shaft, 1,067 kw each Never exceed speed: 330 km/h (178 knots, 207 mph) Maximum speed: 268 km/h (145 knots, 167 mph) Range: 700 km (297 nmi, 342 mi) Service ceiling: 6,500 m (21,300 ft)Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

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BIPIN KUMAR JHA (BKJ) - 1 knots= 0.5144444m/s

SUKHOI T-50 STEALTH FIGHTER


FUTURE INDIAN STEALTH AIRCRAFTSDRDO-AURAAURA (Autonomous Unmanned Research Aircraft) Role -Unmanned Stealth Bomber Manufacturer- DRDO Designer- DRDO First flight- 2015 Introduction -2019-2020 Status -Under Development Primary user- Indian Air Force Indian Navy


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FUTURE INDIAN STEALTH AIRCRAFTSHAL AMCA


HAL AMCAAdvanced Medium Combat Aircraft Role -Stealth multirole fighter Manufacturer- Hindustan Aeronautics Limited Designer Aeronautical Development AgencyDRDOFirst flight- Early 2020s Status- Under development Primary users - Indian Air Force Indian Navy


Future scopeHypersonic- the idea is to travel with M>5 to avoid detection.The infrared Invisibility Cloak:Shield ones body heat from infrared sensors, effectively making them invisible to infrared cameras.Plasma Stealth Technology:Also knows as Active Stealth Technology Uses plasma to reduce the overall radar cross section of an aircraft.TARANIS: A semi autonomous unmanned war plane designed to fly intercontinental missions. It will carry a variety of weapons enabling it to attack both aerial and ground targets.To be incorporated not only in fighters and bombers but also in ships, helicopters, tanks and transport planes.Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

conclusion

Undoubtedly, Stealth technology is the Future of Military Combat and at Present is one of the best technology to make things invisible as far as possible.But, the main problem with stealth is its very high cost and because of this, not all nations can adopt this technology. So we need to find ways to reduce cost or adopt a different technology with Stealth like characteristics and at low cost (Nano technology).Mechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

references

Book on Stealth technology-the art of black magic by J.JONESBook on Stealth aircraft by BILL SWEETMAN Future Flight: The Next Generation of Aircraft Technology, William D. Siuru , Jhon D. Busick, Published 1933 McGrew-Hill Professional, 194 pages, ISBN 0830643761Have Blue and the F-117A: Evolution of Stealth Fighter, By David C. Aronstein, Albert C Piccirillo, Published 1997 American Institute of Aeronautics and Astronautics, 305 pages, ISBN 1563472457Stealth technology: The Art of Back Magic, By J. Jones, Matt Thunderhttp://www.geocities.com/Area51/Shadowlands/6583/projects.htmlhttp://en.wikipedia.org/w/index.php?title=Stealth_aitcrafthttp://en.wikipedia.org/wiki/F-117_NighthawkMechanical Aspects in Stealth TechnologyDesigned & Prepared by___ BIPIN KUMAR JHA

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