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STEALTH FIGHTERS

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INTRODUCTION• Stealth technology referred as “VLO” ie “VERY LOW OBSERVABLE TECHNOLOGY”

•Fighter planes are made so they are harder to be detected by the radar and other devices

•The first combat use of stealth aircraft was in December 1989 during Operation Just Cause in Panama

•Well known examples include the United States' F-117 Nighthawk (1980s-2008), the B-2 Spirit "Stealth Bomber," and the F-22 Raptor

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HOW IT WORKS ?

The airplane can be covered in materials that absorb radar signals

The airplane can be shaped so that any radar signals it reflects are reflected away from the radar equipment.

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SHAPE OF AIRCRAFT

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coventional aircraft stealth fighter

SHAPING OF STEALTH•The shape should be flat or rectilinear and at the same time oblique to the incoming waves •Another method bounce back on a very limited number of directions, maybe only one or two •a compact, smoothly blended external geometry to achieve a continuously varying curvature

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LIMITATION WITH SHAPE In addition, surfaces on a stealth

aircraft can be treated so they absorb radar energy as well. The overall result is that a stealth aircraft like an F-117A can have the radar signature of a small bird rather than an airplane. The only exception is when the plane banks -- there will often be a moment when one of the panels of the plane will perfectly reflect a burst of radar energy back to the antenna.

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HISTORY During the First World War, an attempt to

reduce the visibility of military aircraft through the experimental use of "Cellon" plastic transparent covering material resulted in single examples of the Fokker E. I Eindecker fighter monoplane, the Albatros C.I two-seat observation biplane, and one German heavy bomber design, the Linke-Hofmann R.I all being covered with the "Cellon" material; the latter two aircraft had all-wooden structures covered with the "Cellon" material, which degraded rapidly in direct sunlight and were not proceeded with any further. 04/15/23 9

HISTORY•Nearly three decades later, a more serious attempt at "invisibility" was tried with the Horten Ho 229 In addition to the aircraft's shape, which may not have been a deliberate attempt to affect radar deflection, the majority of the Ho 229's wooden skin was bonded together using carbon-impregnated plywood resins designed with the purported intention of absorbing radar waves.•SR 71 the first Stealth airplane launched. It is well known as 'black bird'. 10

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MODERN AIRCRAFT

Modern stealth aircraft first became possible when Denys Overholser, a mathematician working for Lockheed Aircraft during the 1970s, adopted a mathematical model developed by Peter Ufimtsev, a Russian scientist, to develop a computer program called Echo 1. Echo made it possible to predict the radar signature an aircraft made with flat panels, called facets. In 1975, engineers at Lockheed Skunk Works found that an aircraft made with faceted surfaces could have a very low radar signature because the surfaces would radiate almost all of the radar energy away from the receiver

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DEVELOPMENT The first combat use of purpose-designed

stealth aircraft was in December 1989 during Operation Just Cause in Panama. On 20 December 1989, two USAF F-117s bombed a Panamanian Defense Force barracks in Rio Hato, Panama. In 1991, F-117s were tasked with attacking the most heavily fortified targets in Iraq in the opening phase of Operation Desert Storm and were the only jets allowed to operate inside Baghdad's city limits.

5 CONSIDERATIONS RAM RAS IR stealth Plasma stealth OTH

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RAS (RADAR ABSORBENT STRUCTURE”)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.

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RAM (RADAR ABSORBING MATERIAL)

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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 compoundRAM 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. This reduces the radar signature of the aircraft

PLASMA STEALTH•Plasma stealth is a proposed process that uses ionized gas (plasma) to reduce the radar cross section (RCS) of an aircraft. Plasma stealth technology is what can be called as "Active stealth technology" in scientific terms. This technology was first developed by the RussiansIn 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.

Plasma stealth will be incorporated in the MiG-35 "Super Fulcrum / Raptor Killer".

•the wave can be absorbed and converted into thermal energy rather than reflected.

•plasma might also be used to modify the reflected waves to confuse the opponent's radar system

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DETECTION BY INFRARED RADIATION•Passive IR detection devices rely on the fact that every atom of matter, including clouds and rain, continuously sends out electromagnetic radiation at an IR wavelength which corresponds to its temperature.

•For aircraft detection, IR seekers look for contrasts between hot parts on the airframe • •In engine exhausts, carbon dioxide produces most of the IR signature at 4.2 microns

•IR sensors can 'see' at two different wavelengths, (medium: 3-5 microns and long:8-14 microns) to provide good target discrimination. 18

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.

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REDUCING IR EMISSION

OTHER METHODS•to degrading the performance of IRST systems is to ensure that the exhaust dissipates as quickly as possible after leaving the aircraft. •Some of the techniques are follows

1.engines can be fitted with flow mixers to blend the cold bypass air with the hot air that passes through the combustor and the turbine

2.The exhausts geometry can be adapted to a wide and flat shape

3.Interaction between the exhaust stream and the airflow over the aircraft can be engineered to create an additional vortex which further promotes mixing

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OTH Radar (Over the Horizon Radar)•Over-the-horizon radar is a design concept that increases radar's effective range over conventional radar

•It is claimed that the Australian JORN Jindalee Operational Radar Network can overcome certain stealth characteristics.

•It is claimed that the HF frequency used and the method of bouncing radar from ionosphere overcomes the stealth characteristics of the F-117A.

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ACTIVE CANCELLATION•Active cancellation is a theoretical military jamming system that involves the sampling of an incoming radar signal, analyzing it, then returning ths signal slightly out of phase, thus "cancelling" it out.

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LATEST COATING MATERIALPreviously CELLON ,CARBON TITANIUM OXIDE,CARBON BLACK,TINY IRON SPHERES were used as coating materials but latest discovery is NANO PAINTS.Nano paints have taken these aircrafts on the verge of invisibility

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NANO COATINGS The Israel-based YnetNews is Reporting that an Israeli

company called Nanoflight has successfully run a test on dummy missiles that were painted with the nano-enabled coating and have shown that radar could not pick them up as missiles. The nanocoating achieves its radar trickery by absorbing the radio waves emitted by the radar and scattering them as heat energy enough so that when the radar gets the bounced back signal it is not regular enough to indicate an object.

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COST OF OPERATION Stealth aircraft are typically more

expensive to develop and manufacture. An example is the B-2 Spirit that is many times more expensive to manufacture and support than conventional bomber aircraft. The B-2 program cost the U.S. Air Force almost $45 billion.

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USE OF STEALTH AIRCRAFT

stealth aircraft have stealth aircraft have been used in been used in •conflicts, conflicts, including Operation including Operation Desert Desert Storm, Operation Storm, Operation Allied Force and Allied Force and the 2003 invasion of the 2003 invasion of Iraq.Iraq.

•employed to strike employed to strike high-value targetshigh-value targets

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FUTURE OF STEALTH AIRCRAFTS

The F-22 Raptor fifth generation stealth air superiority fighter Naval variant of the F-35 Lightning II fifth-generation stealth

multi-role fighter A Sukhoi PAK FA fifth-generation stealth multirole fighter Stealth aircraft will continue to play a valuable role in air combat

with the United States using the F-22 Raptor, B-2 Spirit, and the F-35 Lightning II to perform a variety of operations.[

The Russian Sukhoi PAK FA stealth multi-role fighter is scheduled to be introduced from 2015, to perform various missions.

The Sukhoi/HAL FGFA, the Indian version of the PAK FA is scheduled to be introduced from 2017 in higher numbers, also to perform various missions.

The People's Republic of China plans to introduce the Chengdu J-20 stealth multi-role fighter round 2018. A prototype was flown in early 2011.[

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How to See Stealth

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NOT STEALTH

STEALTH

DO NOT HAVE BAY DOORS – THE TWO SIDE-BAY DOORS ARE OPEN HERE

QUERIES

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THANK YOU

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