6th GENERATION STEALTH AIRCRAFT

International Journal of Research In Science & Engineering e-ISSN: 2394-8299
Volume: 1 Issue: 2 p-ISSN: 2394-8280
IJRISE| www.ijrise.org|editor@ijrise.org [07-12]
6th
GENERATION STEALTH AIRCRAFT
INDRADEEP KUMAR
Aeronautical Engineering 3rd
year
MATS School of Engineering and IT, MATS University, Raipur
indradeep1989@gmail.com
Stealth aircrafts are aircraft that use stealth technology to avoid detection by employing a combination of
features to interfere with radar as well as reduce visibility in the infrared visual, audio, and radio frequency (RF)
spectrum. While no aircraft is totally invisible to radar, stealth aircraft prevent conventional radar from detecting
or tracking the aircraft effectively, reducing the odds of a successful attack. Stealth is the combination of passive
low observable (LO) features and active emitters such as Low Probability of Intercept Radars, radios and laser
designators. These are usually combined with active defenses such as chaff, flares, and ECM. Stealth refers to
the act of trying to hide or evade detection, For airplanes, stealth first meant hiding from radar. It is not so much
a technology as a concept that incorporates a broad series of technologies and design features. This paper shows
the development of stealthy airplanes which teaches several important lessons about technology. The first is that
often many different technologies like Nano-Technology with Aerodynamics must be combined to achieve a
desired outcome. An advance in one field, such as materials or aerodynamics, must be accompanied by advances
in other fields, such as computing, constructing or electromagnetic theory. The second lesson is that sometimes
trial and error techniques are insufficient and advances in mathematical theory are necessary in order to achieve
significant advances. Finally, stealth teaches the lesson that technology is never static - a "stealth breakthrough"
may only last for a few years before an adversary finds a means of countering it. So this paper deals with how to
handle the Stealth. This paper also shows how and where to use Nano-Technology.
KEYWORDS: Nano-Technology, Stealth, RADAR, Visual Stealth, Infrared Stealth, Acoustic Stealth, Plasma
Stealth etc.
INTRODUCTION
Stealth technology is a sub-discipline of military countermeasures which covers a range of techniques used with
aircraft, ships and missiles, in order to make them less visible (ideally invisible) to radar, infrared and other
detection methods. Stealth technology (often referred to as "LO", for "low observability") is not a single technology
but is a combination of technologies that attempt to greatly reduce the distances at which a vehicle can be detected.
The concept of stealth is not new: being able to operate without the knowledge of the enemy has always been a goal
of military technology and techniques. However, as the potency of detection and interception technologies (radar,
IRST, surface-to-air missiles etc.) has increased, so too has the extent to which the design and operation of military
vehicles have been affected in response. A 'stealth' vehicle will generally have been designed fromthe outset to have
reduced or controlled signature. It is possible to have varying degrees of stealth. The exact level and nature of stealth
embodied in a particular design is determined by the prediction of likely threat capabilities and the balance of other
considerations, including the raw unit cost of the system.
A mission system employing stealth may well become detected at some point within a given mission, such as when
the target is destroyed, however correct use of stealth systems should seek to minimize the possibility of detection.
Attacking with surprise gives the attacker more time to perform its mission and exit before the defending force can
counter-attack. If a surface-to-air missile battery defending a target observes a bomb falling and surmises that there
must be a stealth aircraft in the vicinity, for example, it is still unable to respond if it cannot get a lock on the aircraft
in order to feed guidance information to its missiles.
DEFINITION
Stealth technology is the use of special radar absorbent materials, flat angular surface design and other techniques to
minimize the amount of radiation reflected to a radar installation, causing an aircraft or other vehicle to appear as a
much smaller signal or not at all.
HISTORY

Development of stealth technology for aircraft began before World War I. Because RADAR had not been invented,
visibility was the sole concern, and the goal was to create aircraft that were hard to see. In 1912, German designers
produced a largely transparent monoplane; its wings and fuselage were covered by a transparent material derived
from cellulose, rather than the opaque canvas standard in that era. Interior struts and other parts were painted with
light colors to further reduce visibility. The plane was effectively invisible from the ground when flow at 900 ft (274
m) or higher, and faintly visible at lower altitudes. Several transparent German aircraft saw combat during World
War I, and Soviet aircraft designers attempted the design of transparent aircraft in the 1930s.
With the invention of RADAR during World War II, stealth became both more needful and more feasible: more
needful because RADAR was highly effective at detecting aircraft, and would soon be adapted to guiding
antiaircraft missiles and gunnery at them, yet more feasible because to be RADAR-stealthy an aircraft did need to be
not be completely transparent to radio waves; it could absorb or deflect them.
.AIM OF STELTH TECHNOLOGY
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. The metal body of an airplane is very good at reflecting radar
signals, and this makes it easy to find and track airplanes with radar equipment. The goal of stealth technology is to
make an airplane invisible 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. The goal of stealth techniques is to bounce so little radar power back to its source
that the target is nearly impossible to detect or track.
DETECTION TECHNIQUES
Following are the techniques of detection for aircraft
 RADAR
 Heat detection
 Turbulence detection
 Visual detection
Radar is a system that allows the location, speed, and/or direction of a vehicle to be tracked. The word "radar" is
actually an acronym standing for Radio Detection And Ranging since the device uses radio waves to detect targets.
Radar works by sending out pulses of these electromagnetic waves and then "listening" for echoes bounced back by
targets of interest. Even though a radar may transmit megawatts of power in a single pulse, only a tiny fraction of
that energy is typically bounced back to be received by the radar antenna. The amount of power returned from a
target to the transmitting radar depends on four major factors:
1. The power transmitted in the direction of the target
2. The amount of power that impacts the target and is reflected back in the direction of the radar
3. The amount of reflected power that is intercepted by the radar antenna
4. The length of time in which the radar is pointed at the target.
STEALTH TECHNIQUES
Stealth Technology is used in the construction of mobile military systems such as aircrafts and ships to significantly
reduce their detection by enemy, primarily by an enemy RADAR. The way most airplane identification works is by
constantly bombarding airspace with a RADAR signal. Other methods focus on measuring acoustic (sound)
disturbances, visual contact, and infrared (heat) signatures. Stealth technologies work by reducing or eliminating
these telltale signals. Panels on planes are angled so that radar is scattered and no signal returns . Planes are also
covered in a layer of absorbent materials that reduce any other signature the plane might leave. Shape also has a lot
to do with the `invisibility' of stealth planes. Extreme aerodynamics keeps air turbulence to a minimum and cut

down on flying noise. Special low-noise engines are contained inside the body of the plane. Hot fumes are then
capable of being mixed with cool air before leaving the plane. This fools heat sensors on the ground. This also keeps
heat seeking missiles from getting any sort of a lock on their targets.
1. VISUAL STEALTH
Low visibility is desirable for all military aircraft and is essential for stealth aircraft. It is achieved by coloring the
aircraft so that it tends to blend in with its environment.
2. INFRARED STEALTH
Infrared radiation (i.e., electromagnetic waves in the. 72–1000 micron range of the spectrum) are emitted by all
matter above absolute zero; hot materials, such as engine exhaust gases or wing surfaces heated by friction with the
air, emit more infrared radiation than cooler materials. Heat-seeking missiles and other weapons zero in on the
infrared glow of hot aircraft parts.
3 ACOUSTIC STEALTH
Although sound moves too slowly to be an effective locating signal for antiaircraft weapons, for low-altitude flying
it is still best to be inaudible to ground observers.
4 PLASMA STEALTH
Plasma absorbs radio waves, so it is theoretically possible to diminish the RADAR reflectivity of an aircraft
otherwise non-stealthy aircraft by a factor of 100 or more by generating plasma at the nose and leading edges of an
aircraft and allowing it flow backward over the fuselage and wings.
COUNTER STEALTH TECHNIQUE
An aircraft cannot be made truly invisible. For example, no matter how cool the exhaust vents of an aircraft are kept,
the same amount of heat is always liberated by burning a given amount of fuel, and this heat must be left behind the
aircraft as a trail of warm air. Infrared-detecting devices might be devised that could image this heat trail as it
formed, tracking a stealth aircraft.
No single receiver may record a strong or steady echo fromany single transmitter, but the network as a whole might
collect enough information to track a stealth target. Anti-Stealth/ counter stealth can be achieved:
1. By triangulating its location with a network of radar systems.
2. With the help of microwaves similar to the ones emitted by the cell phone towers.
3. By using over the horizon radar, ultra wide band (impulse) radar, bi-static radar, imaging radar and IR imaging
seekers.
DRAWBACK OF STEALTH TECHNOLOGY
Stealth technology has its own drawback like other technologies.
1. Stealth aircraft cannot fly as fast or is not maneuverable like conventional aircraft.
2. Another serious drawback 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.
3. Since the radar cross-section of an aircraft depends on the angle from which it is viewed, an aircraft will
typically have a much smaller RCS when viewed from the front or rear than when viewed from the side or from
above. In general stealth aircraft are designed to minimize their frontal RCS. But it is not possible to contour the
surface of an aircraft to reduce the RCS equally in all directions, and reductions in the frontal RCS may lead to
a larger RCS from above.

Fig: All the three view of the Aircraft.
4. Another drawback of stealth aircraft is their vulnerability to detection by bi-static radars.
HOW TO OVERCOME OR ELIMINATE THE DRABACK OF STEALTH TECHNOLOGY.
The drawback of this technology can be overcome by the following methods:
1.Aircrat designed primarily to supplement and replace by incorporating new stealth features and propulsion
technology.These advances include its angular design, use of radar-absorbent composite materials, and the ability to
"super cruise" at supersonic speeds without using an afterburner. The Aircraft also emphasizes agility through the
use of thrust vectoring nozzles and a sophisticated fly-by-wire control system.
2. Other advanced systems aboard the Raptor include an integrated avionics suite built around a powerful flight
computer with three times the memory and 16 times the speed can be used and also uses a navy/attack systemthat
incorporates artificial intelligence to filter information to the pilot reducing his workload as well as improving his
situational awareness.
3. The Aircraft can be advanced by incorporating Nano-materials rather than other materials which increases the
strength and reduces the weight hence it can carry more pay load.
4. The contouring of a stealth aircraft is so designed to avoid reflecting a radar signal directly back in the direction
of the radar transmitter from both side of bi-static radars.
WHY IT'S NAME 6TH
GENERATION
Till date the technology used in Aircraft named as 5th
generation Stealth Aircraft while nano- Technology is
used in Aircraft which is of next generation hence its name 6th
generation.
WHERE AND HOW TO USE NANO-TECHNOLOGY
For an aircraft generally Nano-materials are formed by Gas Phase synthesis process as follows:
1. In homogeneous Chemical Vapor Deposition (CVD), particles form in the gas phase and diffuse towards a cold
surface due to Thermo-phoretic forces, and can either be scrapped of from the cold surface to give Nano-
powders, or deposited onto a substrate to yield what is called ‘particulate films’.
2. In heterogeneous CVD, the solid is formed on the substrate surface, which catalyzes the reaction and a dense
film is formed.

In order to form Nano-materials several modified CVD methods have been developed. Gas phase processes have
inherent advantages, some of which are noted here:
1. An excellent control of size, shape, crystallinity and chemical composition
2. Highly pure materials can be obtained
3. Multi-component systems are relatively easy to form and Easy control of the reaction mechanisms.
Uses of Nano-materials in Stealth Aircrafts are as follows:
1. NANO-MATERIALS IN AIRFRAME STRUCTURE
 Carbon Nano-tube (CNT) based Polymer Composites having wide range of Young’s Modulus, High
Specific Strength, Crash Resistance and Thermal Performance and these properties can provide conventional
composites and light weight metals.
 Nano-clays reinforced Polymer Composites having Thermal and Flame Retardant properties.
 Metal Nano-particles incorporated Composites: The extra ordinary electrostatic discharge and electro-
magnetic interference (EMI) shielding properties of these composites make themthe probable futuristic solution
for making the structure which is resistant to lightning strikes.
2. NANO-COATINGS FOR AERO-ENGINE PARTS
 SiC Nano-particles in SiC-particle-reinforced alumina Yittria stabilized Nano-zirconia can facilitate crack
healing, resulting in improved high-temperature, and strength and creep resistance as compared to monolithic
ceramics.
 TiN Nano-crystallites embedded in amorphous Si3N4 are used for Wear-resistant coatings.
 The Nano-composite coatings made of crystalline Carbide, Diamond like Carbide and metal di-
Chalcogenide, TiN are used for low friction and wear resistant applications of aircraft.
 Nanotube and nanoparticles (Nano-graphite, Nano-Aluminium) containing polymer coating are used for
electrostatic discharge, EMI shielding and low Friction applications of aircraft surfaces .
3. NANO-MATERIALS FOR AIRCRAFT ELECTRO-COMMUNICATION COMPONENTS
 Magnetic Nano-particles (Iron oxide Nano-particles i.e. Fe2O3 & Fe3O4) incorporated polymer films and
composites can be used in various Data Storage Media.
 Ceramic Nano-particles like Barium Titanate, Barium Strontium Titanate are used for making Super
Capacitors.
 MEMS (Micro Electro Mechanical Systems) and NEMS (Nano Electro Mechanical Systems) offer the
possibility of developing a standard fuel management unit which controls the fuel control in aero-engines.
CONCLUSION
Stealth has become the magic word in contemporary weapon systems. Contemporary work on stealth has its roots in
long-standing efforts to reduce the visibility of military aircraft through camouflage paint schemes. However, as
electronic sensors have replaced the eyes of pilots as the primary means of tracking other aircraft, more intricate
means of defense were needed. This paper also concluded that potential of Nano-materials with Stealth Technology
in Aviation (Defense) Sector. Using Nano-technology with Stealth Technology in aviation gives the Low
Observability with Light Weight, High Strength, High Toughness, Corrosion Resistance, Less Maintenance &
Durability with increase in carrying Pay load hence it becomes cheaper, safer and used for protecting to be the target
than the conventional. These technology has some drawback also but due to above reason it can be ignored.
AKNOWLEDGEMENTS

I would like to thanks Late M. Nirmala (Administrator Ganesh Institute of Engineering, Chennai), E. Natarajan
(Professor Mechanical Engineering, Anna University, Chennai) Mr. Dilip Kumar and Mr. Pradeep Kumar (Brother)
for their full support for making this paper.
REFRENCES
 www.aerospaceweb.org
 www.howstuffworks.com
 www.wikipedia.com
 www.totalairdominance.com
 EPA Nanotechnology White Paper
 http://www.nanostudent.com
 http://www.nnin.org/nnin_edu.html

6th GENERATION STEALTH AIRCRAFT

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6th GENERATION STEALTH AIRCRAFT