Music The main control surfaces allow the pilot to rotate the aircraft in three dimensions. With each movement there are further effects of controls. These are the four main forces acting on an aeroplane in flight.
The average position of the lift force that is generated by the wings is represented here by the lift arrow. The sum of the aircraft's mass is represented by the weight arrow, always pointing down towards the centre of the earth. The forward thrust generated by the power plant and the resistance called drag are shown by opposing horizontal arrows.
The primary effect of the ailerons is a roll. As the aeroplane rolls, the lift force rolls with it. Now that the vertical component of the lift is smaller and no longer supports the aeroplane's weight, it causes the aeroplane to slide down.
In this example viewed from above, as the aeroplane slides down in the direction of the lower wing, the relative airflow shifts to act from the side. The vertical surface of the rudder is exposed to side-facing airflow, pushing the tail to the left, resulting in a secondary effect that is yaw. The primary effect of rudder is a yaw.
As the aeroplane yaws, the outer wing moves forward, further than the inner wing. Thus it moves a little faster. Faster airflow equals more lift. Viewed from behind. The result is a roll, which is the secondary effect of using the rudder.
The primary effect of the stabilator is pitch. As the aeroplane pitches down, the weight vector now contributes to the forward motion and results in increased airspeed and loss of altitude. The opposite happens to airspeed when the aeroplane is pitched up.
So in summary, These are the primary and secondary effects of controls. From the aeroplane illustrated here, one effect of increased power is a stronger spiralling slipstream behind the propeller. This local volume of faster airflow affects the aeroplane's empennage by making the stabilator and the rudder more sensitive to pilot's inputs. In addition to that, the spiralling slipstream has a tendency to wrap around the fuselage.
It impacts the rudder on the side and induces a yawing moment to the left for a clockwise rotating propeller.