Stealth technology reduces an aircraft's detection by radar through surface designs and radar absorbing materials. Surface designs aim to deflect radar signals away from the source, while RAM absorbs radar waves. Modern stealth aircraft like the F-35 and B-2 Spirit use curved shapes, buried engines, and radar absorbing coatings and structures to achieve a minimal radar cross-section. Stealth technology is an ongoing effort, as advances in radar threaten invisibility, but it has allowed for improved military surveillance and strike capabilities.

1. STEALTH TECHNOLOGY AND IT’S APPLICATIONS IN
AIRCRAFTS

2. What Is Stealth Technology?
 Scientifically known as
low observatory
 Used in Military aviation
 Reduces detection range
of an aircraft
 Similar to camouflage
tactics used by soldiers
 Partial invisibility to
radar and other
detection

3. RADAR SIGNATURE ?
 A radar signature is how big the airplane on radar appears
from a specific angle and distance.
 Radar cross section (RCS): the cross
sectional area of a perfectly reflecting
sphere that would produce the same
signal reflection as would the object.
 Depends on many parameters, like:
 Relative size (size vs. wavelength).
 Target material /painting.
 Shape / orientation.

4. The size of a target's image on radar is
measured by RCS (σ )
Uses the principle of reflection and
absorption as well as redirection.
Minimizes heat and other emissions from
engine and other spots.
Reduces RCS by surface designs of stealth
aircrafts by RAS or RAM

5. How It Reduces RCS ?
The job is performed by using mainly
two techniques:
1.Designing of surface
2.Radar absorbing materials(RAM)
But now a days one more technology
known as “Plasma Stealth Technology” is
also employed

6. 1. Surface Design
 The goal of stealth technology is to
make an airplane almost invisible
to radar.
 Most conventional aircraft have
a rounded shape which means
that no matter where the radar
signal hits the plane, some of the
signal gets reflected back
 The shape of an stealth airplane
is designed in such a way that it
reflects the signals away from the
radar. As shown in the fig. here:

7. Precautions In Designing:
 Sharp Edges
 Design of nose
 Acute angles
 No right angle
 The air craft must
bury the engines
within the wings
 E.g. Lockheed
F-117 Nighthawk

8. Northrop Grumman B-2 Spirit
 Has a completely different design: It has one big
wing, like a boomerang.
 This flying wing design is much more efficient than a
conventional plane. As shown:

9. B-2 continued..
It eliminates the tail and fuselage & also reduces drag i.e. the
total force of air resistance acting on the plane.
Greater efficiency helps the B-2 travel long distances in a
short period of time.
It is high subsonic, means its top speed is just around the
speed of sound (around 305 m/s ) but it can go 6,900 miles
(11,000 km) without refueling and 11,500 miles (18,500 km)
with one in-flight refueling.
The stealth bomber's peculiar shape deflects radio beams in
both ways.

10. Differences Between Normal
Aircraft & Stealth Aircraft
1. Tail Angle Effect:
 A corner reflector is retro reflector
which consists of three mutually
perpendicular, intersecting flat
surfaces, & hence reflects em
waves back to source.
 So tail angle should be kept acute to
decrease detection. As Shown below:

11. •Exhaust Plume of a
normal Aircraft
• Stealth Aircraft without
Exhaust.
4. Exhaust plume

12. 2. Difference In Aircraft Design
When we are using normal
shape
When using stealth
technology.

13. Normal fighter plane
showing the engine.
Engines of the stealth aircraft
are covered.
3. Engine position

14. 2. Radar Absorbing Materials(RAM)
 Nano structural composite material,
absorbing without reflection radar
wave.
 Magnetic ferrite-based substance
 RAM reduces the radar cross
selection making the object
appear smaller.
 Radiation Absorbing honeycomb
Structural material usually incor-
porated with skin of aircraft

15. Frequency Selective Surfaces(FSS)
 Planar periodic structures that behave like filters to
electromagnetic energy.
 They are like metallic
screens with frequency
selective properties
 Used as ‘spatial filters’
through which a specific
range of Em energy
may be propagated

16. The Lockheed Martin F-35 Lightning II uses
new stealthy radar absorbent material in its
construction which includes fiber-mat.

17. Plasma Stealth
 The Russian Scientists proposed to create a plasma formation
around protected object.
 The aircraft injects a stream of ionized
gas in the form of plasma cloud.
 Prevents radars from seeing it by
absorbing the radar energy in this
plasma cloud
The artificially created
plasma cloud
surrounding the plane
reduces its RCS by a
factor of 100.

18. Infrared Stealth
 Infra-red radiation are emitted by all matter above
absolute temperature zero
 Hot zones such as engine exhaust , wing surface [
friction due to air ] get heated which rather increases
the visibility.
 These part should be kept cool as possible it can be ,
 Option would be mixing of cool air with the hot
engine exhaust .
 Use compressed gas or liquid nitrogen to cool their
internal parts.

19. Stealth Technology Today
 The F-117A, B-2 and B1-B can be regarded as the three
emblematic LO aircraft of the late '80s.
 The famous F-22A Raptor (1st flight in 1997,
production ended in 2011, with 195planes built, 182
planes operating today) is a Lockheed Martin’s (L.M.)
5th generation air superiority stealth fighter.

20. The Lockheed Martin (L.M.) F-35
Lightning II.
 A multirole 5th generation fighter with stealth
capabilities (first flight in 2006, currently in initial
production and testing).

21. The Sukhoi PAK FA
 A 5th gen., multirole, twin-engine jet fighter, developed
by Sukhoi for the Russian Air Force
 Its prototype, T-50, flew
for the first time in 2010
 Based on PAK FA,
Sukhoi will develop
with HAL (Hindustan
Aeronautics Limited),
the “5th Generation
Fighter Aircraft”
(FGFA) for India.

22. Stealth Technology In Future
 Although U.S. is the dominating country having
most advanced stealth aircrafts but

23. Advantages
 Reduces the causality rates during war
 Saving military budget.
 Utmost importance in anti
terrorist operations
 Develop the military secretes
 Bluff the anti-detective device
 Stealth aircraft are invisible to
Radar
 Actually a fight between radar
technology and stealth technology

24. Disadvantages
 Still not a guaranteed technology
 Not much reliable
 Most of the Stealth Aircrafts can’t fly fast. However
technical advancements re making them capable of it,
 They are not maneuverable.
 Can carry only limited amount of payload.
 High cost of maintenance.
 Very economic.
 Reliability hugely depends upon the tracking radar
system.

25. Conclusions
 A technology of future
 Lots of opportunities lies for scientists, researchers as well
as for students also.
 Success yet to be proved extensively.
 Huge investment is required.
 Opportunity for developing countries to learn the
technology.
 Consider as a war between radar technology and stealth
technology.
 U.S is the leading country with other countries also
investing a huge amount of their investments in the
technology.