Propellers (Theory + Recips) Flashcards
What variables affect the angle of attack?
Forward speed and engine RPM
Define blade or pitch angle:
The angle between the plane of rotation and the chord line of the prop blade.
Five forces that act on propellers:
Centrifugal.
Thrust bending force.
Torque bending force.
Aerodynamic twisting force.
Centrifugal twisting force.
_______ causes one side of the propeller to produce more thrust than the other.
Asymmetrical loading.
Define yaw:
Rotation of the aircraft around its vertical axis.
The ______ is the engine of a twin engine plane whose loss would cause the greatest yawing effect.
Critical engine.
Two things that change on a prop blade from the root to the tip:
Cross section.
Pitch.
3 types of fixed pitch propellers:
Climb.
Cruise.
Standard.
T\F
A climb prop will have a higher pitch than a cruise prop.
False.
Climb props have the lowest pitch of the three types of fixed props.
On a counterweight constant speed prop, oiled directed INTO the prop does what to the pitch of the blades?
Lowers pitch.
On a counterweight constant speed prop, oiled directed OUT of the prop does what to the pitch of the blades?
Increases pitch.
Counterweights assist in feathering
On a non-counterweight prop, oil directed INTO the prop does what to the pitch?
Increases pitch.
Assisted by aerodynamic twisting force.
On a non-counterweight prop, oil directed out of the prop does what to the pitch?
Lowers the pitch.
Assisted by centrifugal twisting force and a spring.
Three important parts of the governor:
Oil pump.
Pilot valve.
Flyweights.
What component is used on some feathering propellers to speed up unfeathering action?
Accumulator.
What is the purpose of an accumulator on some feathering engines?
To speed up unfeathering.
