Propellers Flashcards
WHAT IS THE FUNCTION OF A PROPELLER
To create thrust to pull or push an airplane through the air
WHAT IS THE DIFFERENCE BETWEEN A FIXED PITCH PROPELLER AND CONTROLLABLE PITCH PROPELLER?
Fixed pitch propeller is one that has a built-in blade angle that cannot be changed, these propellers can have the blade angle changed by the manufacturer or an approved repair station.
Controllable pitch propeller is one that can be changed by the pilot and is usually controlled by a governor that maintains a constant speed.
HOW ARE SOME WOODEN PROPELLER BLADES PROTECTED FROM WEAR AND DAMAGE
Metal tipping fastened to the leading edge and tip
WHAT HAPPENS TO THE BLADE ANGLE OF A CONSTANT SPEED PROPELLER DURING A CONSTANT POWER DIVE
Blade angle increases to prevent an overspeed
WHAT ARE THE FUNCTIONS OF A CONSTANT SPEED PROPELLER GOVERNOR
1) Boosts engine oil pressure before it enters the propeller hub
2) Senses rotational speed of the propeller
3) Controls oil flow to the propeller hub to change pitch of the propeller
WHAT IS THE PURPOSE OF PROPELLER COUNTERWEIGHTS?
Centrifugal force acting on the counterweights causes the blade angle to increase
WHAT IS MEANT WHEN A PROPELLER GOVERNOR IS IN AN “ON SPEED” CONDITION?
The governor is not accelerating or decelerating and the speeder spring and flyweight forces are in balance
HOW IS A CONSTANT SPEED FEATHERING PROPELLER FEATHERED
Releasing oil pressure in the governor, the counterweights and feathering spring move the propeller into feather. This happens automatically if the governor oil pressure drops to zero or can be manually controlled by the pilot
WHAT IS AN UNFEATHERING ACCUMULATOR?
An oil accumulator used to provide oil pressure to unfeather a propeller
WHAT IS “ALPHA RANGE” AND “BETA RANGE” AND WHERE ARE THEY FOUND
Alpha range, the propeller is operating in the standard, constant speed mode, which is usually in flight.
Beta range operates in the zero or minimum thrust range and negative thrust mode, which is usually on the ground
