PARA SA MGA WALA PANG ICE PROTECTIONS SYSTEM

1. Aircraft Anti-Icing Systems
GROUP 1
Clinton Anoche
Carlo Jae Rillera
Jason Clark Alonto

2. Anti Icing System
 Anti-Icing – Prevention of the formation of ice on a surface.
 De-Icing – The removal of ice that has formed on a surface.
 Ice on a propeller blade or wings changes its airfoil shape and decreases the thrust it
produces. Though rare to minimal, it can also create an unbalanced condition which
produces vibration that can damage the engine as well as the airframe.

3. Negative Effects of Ice Buildup
Destroys smooth flow of air over wing,
leading to severe decrease in lift and
increase in drag forces
Can change pitching moment
As angle of attack is increased to
compensate for decreased lift, more
accumulation can occur on lower wing
surface
Causes damage to external equipment
such as antennae and can clog inlets, and
cause impact damage to fuselage and
engines
Considered a cumulative hazard because
as ice builds up on the wing, it
increasingly changes the flight
characteristics
•http://www.aopa.org/asf/publications/sa11.pdf#search=%22anti-icing%20systems%20aircraft%22

4. Types of Ice
Rime: “has a rough milky white
appearance and generally follows the
surface closely”
Clear/Glaze: “sometimes clear and
smooth but usually contain some air
pockets that result in a lumpy translucent
appearance, denser, harder and more
difficult to break than rime ice”
Mixed
http://virtualskies.arc.nasa.gov/weather/tutorial/images/32clearice.gif&imgrefurl=http://virtualskies.arc.nasa.gov/weather/tuto
rial/tutorial4.html&h=235&w=280&sz=29&hl=en&start=6&tbnid=NrYdps_943cEmM:&tbnh=96&tbnw=114

5. Ice Detection
Electronic ice detection common, but can give false
readings
GM is developing a mass based ice detection system where
ice builds up on external probe
After mass of probe has increased due to additional ice, anti-
icing systems are alerted and turned on
This increases fuel efficiency and system life as de-icing
systems are only turned on as required by conditions

6. Types of Ice Removal
Anti-Icing
Preemptive, turned on before the flight enters icing conditions
Includes: thermal heat, prop heat, pitot heat, fuel vent heat,
windshield heat, and fluid surface de-icers
De-Icing
Reactive, used after there has been significant ice build up
Includes surface de-ice equipment such as boots, weeping wing
systems, and heated wings

7. Propeller Anti-Icers
Ice usually appears on propeller
before it forms on the wing
Can be treated with chemicals from
slinger rings on the prop hub
Graphite electric resistance heaters on
leading edges of blades can also be
used
•http://www.aopa.org/asf/publications/sa11.pdf#search=%22anti-icing%20systems%20aircraft%22

8. The earliest propeller ice control, a system that is still in use, is chemical anti-icing.
Isopropyl alcohol is carried in a tank in the aircraft, and when icing conditions are
anticipated, some of it is pumped into a slinger ring around the propeller hub. The
ring-supply tubes deliver the alcohol to propeller leading edge by centrifugal force
and grooved de-icer boots help carry it out of the lenght of the blades.

9. This is a diagram of a typical system used on a twin
turboprop airplane. Current flows from the bus
through the 20-amp Auto Prop Deice circuit
breakers/switch into the deicer time unit. When the
manual-override relays are not energized, this
current flows through brushes riding on slip rings
mounted on the propeller spinner bulk-head and into
the heating elements bonded to the propeller
blades. The slip rings are connected to the heater
elements through flexible conductors that allow the
blades to change their pitch angle

10. The Timer sends current through the right propeller for about 90 second
then switches over and sends current throught the left propeller for 90 seconds.
Current cycles of the two propellers are controlled by the timer as long as the
propeller Auto Prop Deice switch is ON. Manufacturers limit the operation of the
propeller de-icing system on the ground because the inflight air cooling is not
present and prolonged use will cause damage.

11. Windshield Anti-Icers
• Usually uses resistance heat
to clear windshield or
chemical sprays while on the
ground
Liquids used include: ethylene glycol, propylene glycol,
Grade B Isopropyl alcohol, urea, sodium acetate,
potassium acetate, sodium formate, and chloride salts
Chemicals are often bad for the environment
•http://www.aopa.org/asf/publications/sa11.pdf#search=%22anti-icing%20systems%20aircraft%22

12. Thermal Heat
Air Heated
Bleed air from engine heats inlet cowls to
keep ice from forming
Bleed air can be ducted to wings to heat
wing surface as well
Ice can also build up within engine, so
shutoff valves need to be incorporated in
design
Usually used to protect leading edge slat,
and engine inlet cowls
Resistance heater
Used to prevent ice from forming on pitot
tubes, stall vanes, temperature probes, and
drain masts
Airplane Design, Book 4, Roskam

15. Boots
Inflatable rubber strips that run
along the leading edge of wing and
tail surfaces
When inflated, they expand
knocking ice off of wing surface
After ice has been removed, suction
is applied to boots, returning them
to the original shape for normal
flight
Usually used on smaller planes
•http://www.aopa.org/asf/publications/sa11.pdf#search=%22anti-icing%20systems%20aircraft%22

16. Weeping Wing
Fluid is pumped through mesh screen
on leading edge of wing and tail
Chemical is distributed over wing
surface, melting ice
Can also be used on propeller blades
and windshields
•http://www.aopa.org/asf/publications/sa11.pdf#search=%22anti-icing%20systems%20aircraft%22

17. Electro-impulse Deicing
 Electromagnetic coil under the skin
induces strong eddy currents on
surface
 Delivers mechanical impulses to the
surface on which ice has formed
 Strong opposing forces formed
between coil and skin
 Resulting acceleration sheds ice from
the surface
 Can shed ice as thin as 0.05”
•http://www.idiny.com/eidi.html

18. Typical Anti-Icing
C-130:
Engine bleed air used for anti-icing wing and empennage leading
edges, radome, and engine inlet air ducts.
Electrical heat provides anti-icing for propellers, windshield, and
pitot tubes.
777:
Engine bleed air used to heat engine cowl inlets. If leak is detected
in Anti-Ice duct, affected engine Anti-Ice valves close.
Wing Anti-Ice System provides bleed air to three leading edge slats
on each wing. Wing Anti-Ice is only available in flight.

19. References
 “Airplane Design, Pt 4.” Roskam
 http://www.aopa.org/asf/publications/sa11.pdf#search=%22anti-icing%
 http://www.newpiper.com/promo/PIIPS/images/PIIPSPropSlingerRing.
 http://www.fas.org/man/dod-101/sys/ac/c-130.htm
 http://www.airs-icing.org/AIRS_II/AIAAReno2006/AIAA-2006-
206-739.pdf#search=%22transport%20ice%20%22in%20flight
%22%22
 www.p2pays.org/ref/07/06047.pdf
 Ice Pictures
 http://www.idiny.com/eidi.html