Propellers

A McCauley propeller designated as 1B90/CM7448 has a diameter of ______ inches and a pitch of ______ inches at the 75% station

74, 48

What is a reference station on a propeller blade that is measured from the center of the hub?

a blade station

Most wooden propellers are now made of ____________________ or __________________

birch or ash

A _____________ _____________ is designed primarily to increase the flow of cooling air to the engine nacelle

blade cuff

What occurs because aerodynamic and mechanical forces tend to bend the propeller blades forward at the tips as well as the mechanical power pulses in a reciprocating engine?

blade vibration

Propeller blade stations are measured, in inches, from the

center of the hub

Which force causes the greatest stress and tends to pull the blades out of the hub?

centrifugal force

The six forces that act on a rotating propeller are:

centrifugal force, thrust bending force, torque bending force, aerodynamic twisting moment, centrifugal twisting moment, blade vibration

An aircraft manufacturer may specify two models of a propeller for the same installation, a ________________ and a _______________ propeller

climb, cruise

Automatic propellers are usually termed _________________ __________________ propellers

constant speed

The _________________ pitch is the distance, in inches, that the aircraft actually moves forward in one revolution of the propeller.

effective

The flat surface of a propeller blade is called the ___________ of the blade

face

"Normally, aerodynamic twisting moment is greater than centrifugal twisting moment." This statement is __________

false

________________-pitch propellers are simple propellers whose blade angle cannot be changes in normal operation

fixed

Aluminum propeller blanks are _______________ from high strength aluminum alloy

forged

Thrust bending force tries to bend the tip of a propeller blade _______________________

forward

The ______________________ pitch is the distance, in inches, that a propeller would move in a medium that allowed no slip.

geometric

Aerodynamic twisting moment tries to move the propeller blades toward a ________ pitch angle

high

On a given propeller blade, the blade angle nearest the hub will be the _________________

highest

Centrifugal twisting moment tries to move the propeller blades toward a __________ pitch angle

low

Torque bending force tries to bend the propeller blades in the _______________ direction of their rotation

opposite

The gradual twist in the propeller blade from shank to tip is known as

pitch distribution

Propeller blade angle is the angle between the chord of the propeller blade and the

plane of rotation

Because of vibration problems encountered with certain engine/propeller combinations, the critical range is indicated on the tachometer by a _______________ ____________

red arc

The difference between geometric pitch and effective pitch is called

slip

What is the angle formed by the chord line of the blade and the relative wind?

the angle of attack

What is the acute angle formed by a propeller's plane of rotation and the blade's chord line?

the blade angle

What increases the flow of cooling air to the engine nacelle?

the blade cuffs

What is the imaginary line drawn through an airfoil from the leading edge to the trailing edge?

the chordline

What is the portion of a propeller blade that is furthest from the hub?

the propeller tip

What is determined by the speed that the aircraft moves through the air and the rotational motion of the propeller?

the relative wind

What is the portion of the propeller blade that is nearest the hub?

the shank

What enables a propeller to provide a fairly constant angle of attack along most of the length of the blade?

the twist

The basic function of a propeller on an airplane is to convert engine torque into

thrust

Which force tends to flex the blade tips forward?

thrust bending force

In which force does the air resistance oppose the rotational motion of the propeller blades and tends to bend the blades opposite of the direction of rotation?

torque bending force

______________________ propellers are those mounted on the upstream end of a drive shaft in front of the supporting structure

tractor