Propellers Flashcards
what are the four main parts of a propeller
Tip
Shank
Hub Bore
Hub Assembly
what is propeller pitch? what are the two main types?
Propeller pitch is the distance traveled by an aircraft when a propeller makes one full revolution. the two main types are geometric and Effective
geometric pitch
theoretical distance traveled in on full propeller rotation
Effective pitch
Actual distance traveled in one revolution of the propeller. this number changes based on aircraft power settings
Slip
the difference between geometric and effective pitch
three forces acting on a propeller during flight
Centrifugal
Torque bending
Thrust bending
Constant Speed propeller
Allows for best engine power and most efficient RPM. Propeller angle changed manually by pilot during flight
Feathering
Changing the blade angle to be 90 degrees to the direction of rotation of the propeller
Constant Speed Unit
Boosts engine oil pressure
Controls amount of oil traveling to the propeller
senses rotational speed of the engine
what happens to flyweights when the propeller is overspeed
they flare outwards restricting oil flow to the propellers causing the RPM to lower
when a propeller is rotating at its most efficient RPM, this is called
Onspeed
Underspeed
When the propeller’s RPM is too low, flyweights retract inwards allowing excess oil to flow into the propellers, increasing RPM
what is the difference between De-Icing and Anti - Icing
Deicing uses an electrically heated rubber boot on the leading edge of the propeller
anti icing uses an Isopropyl Alcohol sprinkler that sprays directly onto the propeller
what is the difference between a synchronizer and synchrophaser
synchronizer - matches RPM of multiple propellers (multi - engine)
Synchrophaser - Staggers blades of multiple propellers
why is the synchrophaser off during takeoff
if the master engine shuts down, there can be a reduction in overall engine RPM
