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10 Cards in this Set
- Front
- Back
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Name two vector components that make up the relative wind in the compressor.
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Compressor Rotation (RPM)
Inlet airflow |
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Describe a compressor stall
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When airflow over an airfoil breaks away causing the airfoil to lose lift due to excessive angle of attack.
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Describe the angle of attack of compressor blades and the two factors that determine it.
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AOA: angle between the relative wind and the rotor blade's chordline.
AOA increases with a decrease in inlet airflow or an increase in compressor RPM |
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Identify the indications of a compressor stall
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RPM decay, interstage turbine temperature rise, possible loud noises
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Identify the two main causes of a compressor stall.
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Airflow distortions
mechanical malfuntions |
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Describe how airflow distortions can cause compressor stalls.
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Caused by the breakdown of the airflow through a few stages of the compressor.
As airflow travels back through compressor, angle of rotors and stators change. At high aircraft angles of attack, or when incoming air is slowed or turbulent, possible compressor stalls. |
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Describe four possible mechanical malfunctions that can lead to a compressor stall
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-Variable inlet guide vane and stator vane failure
-Fuel control unit failure -Foreign Object Damage -Variable exhaust nozzle failure |
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Describe what a pilot can do to minimize the potential of a compressor stall.
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Avoid erratic or abrupt Power Control Lever movements, especially at low airspeeds or high angles of attack.
Maintain the minimum airspeed and avoid abrupt changes in aircraft attitude. Avoid flight through severe weather and turbulence |
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Describe four components that can be incorporated into an engine design to minimize the potential of a compressor stall.
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1) Variable inlet guide vane and stator vanes installed
2) Dual/Twin/split-spool compressor 3)Bleed Valves 4) Variable exhaust nozzle failure |
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State the steps to be taken if compressor stall occurs.
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Reduce attitude of aircraft
PCL should be retarded to just below stall threshold Bleed valves PCL slowly advanced once conditions are normal |
