Module 17.5 Propeller Ice Protection Flashcards
What regions are most at risk from ice?
Propeller blades
Spinner
Air intake
Name the two main ice protection methods.
Fluid anti-ice system
Electrical de-icing system
What type of engine are fluid anti-icing systems found on?
Piston-engined aircraft.
Why can’t fluid anti-icing systems be used on turboprop engines?
The fluid that is used can contaminate the compressor blades.
What is used as anti-icing fluid?
Iso-Propyl-Alcohol
Where is the anti-icing fluid stored?
In a reservoir housed within the airframe.
What is the anti-icing fluid pump controlled by?
A rheostat in the cockpit.
What does the anti-icing fluid pump do?
Injects filtered fluid through a fixed nozzle into a ‘U’ shaped slinger ring on each propeller.
What is used to force the fluid from the slinger ring onto the grooved anti-icing rubber boots?
Centrifugal force
Where are de-icing heating elements mounted?
Internally or externally on the propeller spinner and blades.
How is the electrical power transferred to the propeller hub?
Through electrical leads, which terminate in slip rings and brushes.
What is used to transfer electrical power from the hub to the blades?
Flexible connectors
Where are the de-icing heating boots/mats bonded to?
The inner third of each propeller blade.
Where are the spring loaded carbon bushes and copper slip rings attached to?
The back of the rotating propeller hub.
How is overheating of the electric de-icing element prevented?
It’s only used when the propellers are rotating and for short test periods.
Why is cyclic heating used for electric de-icing elements?
To lessen the load on the aircraft electrical system and prevent run-back.
How long does a fast de-icing cycle last for?
2 minutes
How long does a slow de-icing cycle last for?
6 minutes
What temperatures are a fast de-icing cycle used for?
+10 °C down to -6 °C
What temperatures are a slow de-icing cycle used for?
Temperatures below -6 °C.
