Ice protection system
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.
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[edit] Types of ice protection systems
- Pneumatic deicing boots
- Thermal
- Turbine engine bleed air
- Electrical heating elements
- Electro-mechanical
- Weeping wing
The pneumatic boot is a rubber device attached to a wing's leading edge, invented by the Goodrich Corporation (previously known as B.F. Goodrich) in 1923. Portions of the boot are inflated to break ice off the boot, de-icing the wing. Rubber boots are 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 the jet engine into tubes routed through wings, tail surfaces, and engine inlets.
Electrical 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 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.
[edit] Wing and Flight Surfaces
Ice accumulates on the leading edge of wings, tails, and horizonal stabilizers as an aircraft flies through a cloud containing super-cooled water droplets. 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). As the ice layer grows (accretes), it affects the airflow over the affected surface. If the layer grows large enough, it can create lift or handling problems for the aircraft.
[edit] Rotary Surfaces
Ice can also accumulate on helicopter rotor blades and aircraft propellers. The accretion causes weight and aerodynamic imbalances that are amplified due to the rapid rotation of the propeller or rotor.
[edit] Engine Inlets
Ice accreting on the leading edge (lip) of engine inlets causes flow problems and can lead to ice ingestion. In turbofan engines, laminar airflow is required at the face of the fan. Because of this, most engine ice protection systems are anti-ice systems (prevent build up).
[[[Link title]]]== Related Companies ==
- Goodrich Corporation (formerly B.F. Goodrich), De-icing and Specialty Systems (DSSD)
- Cox & Company, Inc.[1]
- Kelly Aerospace, Thermal Systems Division
- Ice Management Systems
- Hutchinson Aerospace
- Meggitt Thermal Systems
- Aerospace Systems & Technologies
- Accord Software and Systems, Bangalore, India
