Propellers

Question 1

The frontal area the blades move through is called the _________ ____

Answer 1

The frontal area the blades move through is called the propeller disc.

Question 2

at normal aeroplane attitudes, what is the plane of rotation of the propeller disc?

Answer 2

The plane of rotation of the propeller disc is about vertical at normal aeroplane attitudes.

Question 3

Propellers work on which airspeed?

Answer 3

True Airspeed
TAS

Answer 4

On a fixed pitch propeller the angle of attack changes whenever the angle of the relative airflow changes.
The angle of the relative airflow is determined by TAS and RPM.
For a given RPM, a slower TAS results in a larger angle of attack.
A fixed pitch propeller produce its optimum angle of attack at a certain pre-determined cruise speed for the aircraft. At all other speeds it operates less efficiently.

Question 5

Most props spin at about _______RPM

Answer 5

1,000RPM

Question 6

Prop parts (4)

Answer 6

Tip
Root
Blade back - travels back
Thrust face - what the pilot sees

Question 7

Black lever -
Blue lever -

Answer 7

Black - fuel consumption
Blue - prop / speed

Question 8

CTM - ‘fines off’ the blade. What is CTM

Answer 8

Centrifugal Twisting Moment

Question 9

Gas turbine engines are about ___% thermally efficient

Answer 9

Gas turbine engines are about 30% thermally efficient