081.07 PROPELLERS

Question 1

The pitch or blade angle of a propeller is the angle between the (…) and the (…).

Answer 1

The pitch or blade angle of a propeller is the angle between the (chord line) and the (plane of rotation).

Question 2

Geometric pitch of a propeller is the (theoretical/actual) distance a propellerwould advance in one revolution at zero blade angle of attack.

Answer 2

Geometric pitch of a propeller is the (theoretical) distance a propellerwould advance in one revolution at zero blade angle of attack.

Question 3

Effective pitch of a propeller is the (theoretical/actual) distance a propeller advances in one revolution.

Answer 3

Effective pitch of a propeller is the (actual) distance a propeller advances in one revolution.

Question 4

The difference between effective and geometric pitch is called (…).

Answer 4

The difference between effective and geometric pitch is called (propeller slip).

Question 5

Teh reference section of a propeller blade with radius R is usually taken at a distance from the propeller axis equal to (0.25/0.50/0.75/0.90) R.

Answer 5

Teh reference section of a propeller blade with radius R is usually taken at a distance from the propeller axis equal to (0.75) R.

Question 6

A climb propeller has a (fine/course) pitch, a cruise propeller a (fine/course).

Answer 6

A climb propeller has a (fine) pitch, a cruise propeller a (course).

Question 7

Propeller efficiency is the ratio of (…) to (…).

Answer 7

Propeller efficiency is the ratio of (power output or power available Thrust x TAS) to (power input or shaft power Torque x RPM).

Question 8

State to which diagram the following refers:

• feathered propeller
• windmilling propeller
• propeller in cruise
• propeller in reverse operation

Answer 8

State to which diagram the following refers:

• feathered propeller → 3
• windmilling propeller → 4
• propeller in cruise → 1
• propeller in reverse operation → 2

Question 9

A windmilling propeller produces (…) instead of thrust.

Answer 9

A windmilling propeller produces (drag) instead of thrust.

Question 10

State if a windmiling or non-rotating propeller results in larger drag in case of an engine failure.

Answer 10

A windmilling propeller results in larger drag.

Question 11

When an aircraft is in asymmetric flight, the overall sideslip force wich will be created when only slipping towards the running engine will be (forward/aft) of the CG in the (same/opposite) direction as the rudder force.

Answer 11

When an aircraft is in asymmetric flight, the overall sideslip force wich will be created when only slipping towards the running engine will be (aft) of the CG in the (opposite) direction as the rudder force.

- say left engine dead, left rudder will cause the wind to hit the right side of the vertical fin and push the aircraft in the opposite direction. Fin is aft of the CG -

Question 12

Propeller solidity is the ratio of the frontal area of (one blade/all blades/propeller disc) to the frontal area of (one blade/all blades/propeller disc).

Answer 12

Propeller solidity is the ratio of the frontal area of (all blades) to the frontal area of (propeller disc).

Question 13

To increase propeller power absorbtion, the number of blades can be (increased/decreased) and the mean chord of the blade (increased/decreased).

Answer 13

To increase propeller power absorbtion, the number of blades can be (increased) and the mean chord of the blade (increased).

Question 14

During the take-off roll, when the pilot raises the tail in a tail wheeled propeller driven aeroplane, the additional aeroplane yawing tendency is due to the effect of (slipstream/asymmetric blade effect/gyroscopic precession/torque reaction).

Answer 14

During the take-off roll, when the pilot raises the tail in a tail wheeled propeller driven aeroplane, the additional aeroplane yawing tendency is due to the effect of (gyroscopic precession).

Question 15

Propeller gyroscopic effect occurs during a (changing/constant) aeroplane attitude and the effect is most noticable at (high/low) speed and (high/low) prop RPM.

Answer 15

Propeller gyroscopic effect occurs during a (changing) aeroplane attitude and the effect is most noticable at (low) speed and (high) prop RPM.

Question 16

For a clockwise turning propeller, the asymmetric blade effect in the climb at low speed will (roll/yaw) the aeroplane to the (left/right).

Answer 16

For a clockwise turning propeller, the asymmetric blade effect in the climb at low speed will (yaw) the aeroplane to the (left).

- down going blade produces a larger thrust vector -

Question 17

The system where two propellers are rotating in opposite direction on the same shaft is called (counter/contra) rotating propellers.

Answer 17

The system where two propellers are rotating in opposite direction on the same shaft is called (contra) rotating propellers.

Question 18

The system where two propellers are rotating in opposite direction on different engines is called (counter/contra) rotating propellers.

Answer 18

The system where two propellers are rotating in opposite direction ondifferent engines is called (counter) rotating propellers.

Question 19

Torque effect causes a (rolling/yawing) moment while slipstream effect causes a (rolling/yawing) moment.

Answer 19

Torque effect causes a (rolling) moment (in opposite direction of propeller rotation) while slipstream effect causes a (yawing) ​moment.

Question 20

In twin engine aeroplanes with propellers turning clockwise as seen from behind, the (left/right) engine is the critical engine.

Answer 20

In twin engine aeroplanes with propellers turning clockwise as seen from behind, the (left) engine is the critical engine.