17.5 - Propeller Ice Protection Flashcards
What is the purpose of a slinger ring?
The slinger ring is a circular U-Shaped channel mounted on the rear of the propeller assembly on the back of the spinner.
Centrifugal force then transfers the anti icing fluid through nozzles to a receiving cup at each blade root
What is the principal of operation of a slinger ring?
The slinger ring is a circular U-Shaped channel mounted on the rear of the propeller assembly on the back of the spinner.
Centrifugal force then transfers the anti icing fluid through nozzles to a receiving cup at each blade root
How is fluid transferred out along a blade kept at the front of the blade?
Feed-over shoes or boots which are installed on the blade leading edge
These over-shoes are a narrow strip of rubber, extending from the blade root to a blade station that is approximately 75% of the propeller radius
How is fluid transferred out along a blade kept at the front of the blade?
What anti icing fluids can be used?
- Isopropyl Alcohol = low cost and availability
- Phospate compound = less flammable but expensive
Describe the parts of an electrical heating system? (4)
- Electrical energy source
- resistance heating element
- system controls
- necessary wiring
How is power transferred out to the propeller?
Electrical power from the aircraft system is transferred to the propeller hub through electrical leads, which terminate in slip rings and brushes. Flexible connectors are used to transfer power from the hub to the blade elements.
Where are carbon brushes located?
To transfer electrical power from the aircraft to the propeller hub through electrical leads which terminate in slip rings and brushes
Explain the timing system on a propeller heating system?
fast cycle - 2 mins - +10 to -6 degrees
slow cycle - 6 mins - below -6 degrees
What detrimental effects have ice got on a propeller?
Loss in prop efficiency
as
Generally, ice collects unsymmetrically on a propeller blade and produces propeller unbalance and destructive vibration.
