STEALTH TECHNOLOGY: A REVEALING An investigative study on stealth technology.

1
STEALTH TECHNOLOGYA REVEALING An investigative
study on stealth technology.
2
What is it?

• RADAR to detect position of objects.
• Counter measures 1. ECM ( e.g. chaff cartridges)
  2. Non ECM
• Avoiding detection and innovating deception .
• RCS reductions, acoustics, thermal and other EM
  emissions

3
Examples

• F 117
• B-2 Bomber
• F-22 Raptor( From YF 23 Platform)
• SR-71 Black bird
• HMS Helsingborg

4
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.

5
Vehicle shape and structure

• Smooth edges maximum radio wave reflectors.
• The size of a target's image on radar is measured
  by RCS (s )
• For a square flat plate of 1m2 area, s13982 m2
  at 10 Ghz

6
Vehicle structure (contd..)

• Mainly plan form alignment.
• The leading edges of wing and tail surfaces set
  at same angles.

7
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.

8
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 .

9
RAMs (contd..)

• Small cell foams painted or loaded with absorbing
  ink.
• MAGRAM
• R- Card
• Absorbing honeycomb
• Transparent RAM

10
Other fields

• Reducing RCS alone not enough.
• More difficulty is reducing the IR signature.
• Interest is near IR region. (shorter than 10 µm)

11
IR Emission

• Major IR emission sources.
• 1. Tailpipe region
• 2. Turbojets have EGTs of 1000oC
• 3. Exhaust gas plume
• 4. Hot engine parts
• 5. Aircraft skin (frictional heating)
• 6. Reflected and reemitted sunlight.

12
IR Reduction

• Using surface paints
• Non circular tail pipe
• Emissions from hot parts screened by airframe.
• The plume mixed with cool air.

13
IR Reduction (contd)

• IR best transmitted 2.5, 4 and 10 micron bands.
• IR outside window absorbed by CO2
• Passive IR target acquisition systems more used.

14
Electromagnetic emissions

• EM emissions other than IR .
• The greatest source is RADAR itself.
• Shutting down RADAR a solution having negative
  effects.
• Radio /radar altimeters and Doppler navigation
  systems.

15
EM emissions (contd)

• Use of inertial navigation , laser or millimetric
  wave system
• Other EM emissions
• 1. Radio communication
• 2. ECM exploited (passive listening)
• 3. Composite materials radiating switching
  transients
• Passive sensors (LPI radar in F-22 ), LOS
  communication, inertial navigation are used.

16
Acoustics

• Most important for submarine ground vehicles.
• Rubber mountings, AIP system, slow turning
  propellers etc.

Visibility

• Matte paint, gray paint in disruptive
  
  
  schemes , yehudi lights
  ( active camouflage).

17
How to counter.

• Background of stealth craft than craft shall be
  searched for.
• High flying aircraft with SLAR, FLIR etc are
  used.
• Same method advantageously used using satellite.

18
Stealth counter (contd.)

• Uninterrupted radio waves from stars mapped.
• Failure or fainter image suggests probability of
  stealthy craft.
• Advantages of using lethal SAMs and remain
  undetected.
• Low frequency radar nullifies stealth from shape.

19
Stealth counter (contd.)

• Disadvantages of LFR
• 1. Wavelength unavailability
• 2. Inaccuracy
• 3. Size
• 1. Bistatic radars and
• 2. Using reflections from civilian radio
  transmitters.
• gives better detection.

20
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.

21
Thank You.....!
For the time spared