Ice protection
From Wikipedia, the free encyclopedia
Ice Protection systems are designed to keep atmospheric ice from accumulating on aircraft flight surfaces while in flight. The effects of ice accretion on an aircraft can cause loss of control, resulting in a catastrophic flight event. Ice forms because super-cooled water droplets in clouds contact the aircraft. This contact imparts energy into the droplet and causes it to change from liquid water to solid water (ice).
[edit] Types of Ice Protection Systems
- Pneumatic Boot, or Deicing boot
- Bleed Air
- Electro-thermal
- Electro-mechanical
- Weeping Wing
The pneumatic boot was invented by the Goodrich Corporation (previously known as B.F. Goodrich) in 1923. The pneumatic boot is a rubber device that is glued to the leading edge. Portions of the boot are inflated to break ice off of the boot (called de-icing). The rubber boot is used on jets and propeller driven aircraft.
A bleed air system is used by jet aircraft to keep flight surfaces above the freezing temperature required for ice to accumulate (called anti-icing). The hot air is "Bled" off of the jet engine in tubes, and is routed to the wing, tail or engine lip.
Electro-thermal systems use electricity to heat the protected surface. The electric heaters are usually flexible enough to use as anti-icers or de-icers. As a de-icer, the heater melts the ice, the ice no longer sticks to the surface due to aerodynamic forces. As an anti-icer, the heater keeps the surface to the point that the ice does not form.
Electro-mechanical systems use a mechanical force to knock the ice off of the flight surface. Typically, actuators are installed underneath the skin of the structure. The actuator is moved to induce a shock wave in the protected surface to dislodge the ice.
A weeping wing system uses a liquid (such as ethylene glycol) to coat the surface and prevent ice from accumulating.
