Worksheets4.1. Propeller Principle
Total questions: 67
Worksheet time: 34mins
What is the function of the propeller?
maintain a constant engine speed
convert engine power into shaft horsepower
convert engine power into propulsive force
The basic cross-sectional shape of the propeller blade is similar to?
Aircraft Wings
Fuselage of airplane
Propeller spinner
Which part of aircraft is similar to the propeller blade basic cross-sectional shape?
Aircraft Wings
Aircraft Fuselage
Helicopter Rotor Head
What is mechanism usually reduce the r.p.m. of the propeller in relation to the engine r.p.m.?
A Gearbox
Constant Speed Unit
Propeller Brake Unit
What is the function of propeller gear box?
Reduce the r.p.m. of the propeller in relation to the engine r.p.m.
Reduce the engine r.p.m. In relation to the r.p.m. of the propeller
Increase the r.p.m. of the propeller in relation to the engine r.p.m.
With the aircraft's engine running, when the propeller blade moves through the air, what forces are generated?
torque and weight
thrust and torque
weight, thrust and lift
The propulsive force that is produced when the propeller blade moves through the air is known as?
Torque
Lift
Thrust
What force generates a resistance to rotation of propeller?
Lift
Thrust
Torque
What is the geometric pitch of a propeller?
The force tends to bend the propeller blades forward in the direction
The forces will tends to turn the propeller blade towards coarser pitch
The distance which it should move forward in one revolution without slip
What forces act on a propeller blade?
a). Thrust and torque.
b). Bending, thrust, torque.
c). Centrifugal, bending and twisting
What force will cause radial stress in the propeller blades?
Bending forces
Twisting forces
Centrifugal forces
The force that tends to pull the propeller blades out of the hub;
Centrifugal force
Aerodynamic force
Torque bending force
The centrifugal twisting moment, which is at 90 degrees to the blade axis tend to turn the blade to: -
finer pitch
courser pitch
extra fine pitch
The Centrifugal force which acts at 90 degree to the blade axis will tends to:
Produce radial stress.
Turn the blade to courser pitch.
Turn the blade to finer pitch
Fixed pitch propeller are usually classified by;
length and diameter
diameter and pitch
pitch and length
What operational force tends to bend the propeller blades forward in the direction?
Centrifugal twisting force
Torque bending force
Thrust bending force
Set up a bending tendency of the blades against the direction of rotation:-
Thrust Forces
Torque Forces
Air Loads
What is the force that set up a bending tendency of the blades against the direction of rotation?
Air Loads
Thrust Forces
Torque Forces
Which forces will tend to oppose the centrifugal twisting moment?
The Air loads
The Centrifugal Forces
The Twisting Forces
Which forces will tends to turn the propeller blade towards coarser pitch?
Air Loads
Centrifugal Forces
Twisting Forces
Which propeller tip speeds will absorb greater power?
Speed of sound
Low tip speeds
High tip speeds
What is the primary source of propeller noise?
The number of blades
The heavy propeller
High propeller tip speeds
Propeller tip losses and noise can be reduced by :-
sweeping the blade towards the tip
increasing the chord of the blade
increasing the length of the blade
A propeller mounted to the front of the engine is known as?
tractor propeller
pusher propeller
contra rotating propeller
Tractor propeller are those propeller that are fitted:-
in front of the engine
at the rear of the engine
at the side of the aircraft
A propeller mounted to the rear of the engine is known as?
tractor propeller
pusher propeller
contra rotating propeller
Pusher propeller are those propeller that are fitted:-
in front of the engine
at the rear of the engine
at the side of the aircraft
A left handed propeller is one that.
rotates clockwise when viewed from the rear.
rotates clockwise when viewed from the front.
is fitted to an engine on the left side of the aircraft.
Choose CORRECT statement about Left-Handed Propeller;
To rotate clockwise when viewed from the cockpit
Anti-clockwise when viewed from the front of the aircraft
Viewed from the cockpit rotates in an anti-clockwise direction
Why piston engine required a propeller?
convert engine power into thrust
maintain a constant engine speed
convert engine power into shaft horsepower
The propeller produces its propulsive force by imparting a relatively :-
Small acceleration to a large mass of air
Large acceleration to a smaller mass of air
Large acceleration to a larger mass of air
What is Angle of Advance (Helix Angle)?
The angle between the relative airflow and the chord
The angle between the relative airflow and the rotational velocity
The angle between the blade face, or chord at a point and the plane of rotation
The 3 angles of the propeller blades when linked together, the blade angle equal to:
angle of attack plus Helix angle
angle of attack minus Helix angle
angle of advance plus Helix angle
The blade angle of a rotating propeller is measured between the blade chord and:
Plane of rotation
Relative air stream
Helix angle
Blade angle is taken from the chord and:
propeller shaft
relative airflow
plane of rotation
The propeller angle of advance is defined as the angle between plane of rotation and ………….. :-
Chord line
Relative airflow
Helix angle
The angle of attack of a rotating propeller blade is measured between :-
blade chord line and plane of rotation
blade chord line and relative airflow
relative airflow and plane of rotation
What is the angle form between the relative airflow and the blade chord?
Angle of attack
Angle of advance
Clearance angle
The aerodynamic twisting moment tends to move the blade towards:
negative blade pitch
finer blade pitch
coarser blade pitch
Ground Clearance is:
the clearance that exist between the propeller tip and the ground.
the clearance between the propeller tip and the side of the fuselage.
the clearance between ground and chamber.
Forces acting on a propeller are.
centrifugal, twisting, and bending
torque, thrust and centrifugal
torsion, tension and thrust
The purpose of propeller twist is.
coarsen the blade angle at the root.
to maintain Blade Angle along the blade.
to maintain Angle of Attack at the same value along the blade
Why propeller blade is necessary to reduce the blade angle toward the tip?
To increase engine power output
To improve appearance of blade and aircraft design
To maintain an efficient angle of attack along the length of blade
To keep the thrust balanced along the blade length :-
the blade angle is increase from blade root to tip.
the blade angle is reduced from blade root to tip.
the blade angle is maintained constant from root to tip.
The forces that tend to bend the blades of the propeller forward in the direction of flight are: -
centrifugal forces
torque forces
thrust forces
The force acting against the direction of rotation is known as :-
negative thrust.
torque force
wind-milling.
The force that tends to oppose the centrifugal twisting moment and coarsen the blade is known as:
Air load
Torque force
Thrust force
An aircraft having no forward velocity, the angle of advance is :-
equals to zero.
at it's highest angle.
equals angle of attack.
During a static engine ground run, the angle of advance is:
equals to zero
at it's highest angle
equals angle of attack
When the angle of advance is equal to zero?
During aircraft move forward
Aircraft having no forward velocity
When aircraft acting as reverse thrust
What is the most desirable blade angle of attack?
3º to 4º.
1º to 2.
1° to 4º.
Propeller efficiency is defined as:
the thrust of propeller compare to the lift of the wing.
the proportion of propeller thrust to the propeller drag.
the ratio of the thrust power to delivered engine power.
Propeller Slip is defined as:
effective pitch minus geometric pitch
geometric pitch plus effective pitch
geometric pitch minus effective pitch
Propeller Slip is:
the difference between the geometric pitch and effective pitch
effective pitch minus geometric pitch
the similarity between geometric pitch compare to effective pitch
Geometric pitch is:
The actual distance the propeller move forward in one complete rotation.
The distance the propeller should advance in one complete rotation.
Difference between geometric pitch and effective pitch.
The actual distance the propeller moves forward in one complete revolution is known as:
effective pitch
geometric pitch
fixed pitch
What is the Effective Pitch?
The forces it actually advances in one 360° revolution
The distance it actually advances in one 360° revolution
The volume it actually advances in one 360° revolution
The actual distance the propeller moves forward in one complete revolution is known as?
Fixed Pitch
Effective Pitch
Geometric Pitch
To improve the power absorption of the propeller is by:
increasing the 'solidity of the propeller.
Increasing the circumference at the radius.
Increasing the total area of the disc.
Solidity of propeller is:
the ratio of blade area divided by propeller disc area
the ratio of blade area to propeller disc area
the ratio of propeller disc area to total blade area
Which type of aircraft configuration those cause a tendency for propeller driven aircraft to swing to one side on take-off?
Tail wheel undercarriage
Nose wheel undercarriage
Contra-rotating propellers
How to compensate a tendency for propeller driven aircraft to swing to one side on take-off?
Aircraft configurations with tail wheel undercarriage
Aircraft configurations with contra-rotating propellers
Aircraft configurations by increasing extra loading on empennage
This effect arises from the axis of rotation being inclined in relation to the horizontal path of the aircraft when the tail wheel is down;
Slipstream effect
Gyroscopic effect
Asymmetric Blade effect
The torque effect on a tail wheel aircraft that has the propeller rotating anti clockwise direction will cause
Aircraft 'roll' to starboard
Aircraft 'roll' to port
Aircraft 'yaw' to starboard
If the propeller rotates anti-clockwise (from rear) ……………. will tend to rotate the aircraft in the opposite direction;
Slipstream effect
Gyroscopic effect
Torque effect
This rotation causes an asymmetric flow on the fin and rudder so as to induce an aerodynamic force to the left, causing the aircraft to yaw to the right;
Slipstream effect
Gyroscopic effect
Torque effect
As the tail wheel leaves the ground, a torque is applied to the rotating propeller in a nose down sense. The effect of this torque is;
Slipstream effect
Gyroscopic effect
Torque effect
