2. What is it?
Stealth is defined as being secretive or cautious in
movement and action.
RADAR is used to detect position of objects.
Technology avoiding detection and innovating
deception is known as stealth technology.
RCS (Radar cross section)reductions, acoustics,
thermal and other EM emissions
3. How is it achieved.
Absorbs radar waves or deflects to other
directions.
Minimizes heat and other emissions from engine
and other spots.
Makes difficult to detect except closely.
The size of a target's image on radar is measured
by RCS (σ )
4. Vehicle shape and structure
Smooth edges receive maximum radio wave reflectors.
A stealth aircraft on the other hand, is made up of flat
surfaces. When signal hits a stealth plane the signal deflects
away like this.
5. Vehicle structure (contd..)
Mainly plain form alignment.
The leading edges of wing and tail
surfaces set at same angles.
6. Vehicle structure (contd..)
Use of re-entrant triangles behind skin.
Distinctive serrations used in external
airframes.
Propulsion subsystem shaping.
Now in research is fluidic nozzles for
thrust vectoring.
7. Radar Absorbing Materials (RAM)
RAMs often as paints used to absorb
RADAR signals.
Iron ball paint, ferrite in polymer matrix
used.
The cockpit canopy coated with thin layer
of indium tin oxide .
8. RAMs (contd..)
Small cell foams painted or loaded with absorbing ink.
MAGRAM
R- Card
Absorbing honeycomb
Transparent RAM
9. IR Emission
Major IR emission sources.
1. Tailpipe region
2. Turbojets have exhaust gas temperature of 1000oC
3. Exhaust gas plume
4. Hot engine parts
5. Aircraft skin (frictional heating)
6. Reflected and reemitted sunlight.
10. IR Reduction
Using surface paints
Non circular tail pipe
Emissions from hot parts screened by airframe.
The plume mixed with cool air.
11. Electromagnetic emissions
The greatest source is RADAR itself.
Shutting down RADAR a solution having
negative effects.
Radio /radar altimeters and Doppler
navigation systems.
12. Conclusion.
Stealth technology developed a lot.
Investment needed is very high.
High chance of low cost gain.
A lot learned about signature reduction and
absorption.
Useful for other projects.
Success yet to be proved extensively.
13. Examples
F 117
B-2 Bomber
F-22 Raptor( From YF 23 Platform)
SR-71 Black bird
HMS Helsingborg
