12.72.6(a) . direction of rotation; 

Thrust
– the component perpendicular to the plane of rotation

Propeller Torque
– the resistance to motion in the plane of rotation

12.72.6. With the aid of a diagram, identify and define the following for a rotating bladesection: 

12.72.4. Explain the reason for blade (or helical) twist.

The helical twist (which is) the reduction in blade angle from hub to tip is
– to gain the most efficient angle of attack along its whole length at airspeed and rpm
– higher rotational velocity towards the tip of the blade will reduce the angle of attack

12.72.2(d) . angle of attack. 

This is the angle between the chord line of the blade section and the relative airflow

12.72.2(c) . helix (or pitch) angle; 

The angle between forward rotational velocity vector and the plane of rotation of the propeller blade is Helix / Pitch angle

12.72.2(b) . blade angle; 

The angle which the chord – line of a propeller section makes with the plane of rotation is the propeller blade angle

12.72.2(a) . blade section; 

– is an aerofoil
– has a leading edge, trailing edge, chordline and camber

12.72.2. With respect to propeller terminology, define the meaning of the following:

12.70. Airframe Structure

12.70.10. Describe the procedure to tie down (or picket) a light aircraft.

1. Park it into wind
2. Set brakes to park and chock the wheels
3. Lock the control surfaces (control column lock)
4. Tie the aircraft down