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Just as we
require mechanism to control movement of automobiles, in the same way we
require a mechanism to control aircraft movements. This mechanism is provided by
the control surface of aircraft. Control surface of aircraft helps to change
the attitude of the aircraft. Unlike automobiles aircraft move about all the three
axes. Aircraft control surfaces are of two types: primary control surface and
secondary control surface.
Primary control surface of aircraft
Basically primary control surfaces are airfoils which when deflected causes change to the airflow flowing around the aircraft. This disturbance in airflow causes an unbalanced force which is balanced by the movement of aircraft. Thus changing the attitude of the aircraft. Primary control surfaces of aircraft changes the attitude of the aircraft along the three axes to cause three types of movements i.e. pitching, yawing and roll. Primary aircraft control surfaces are aileron, rudder and elevator.
1. Aileron
Ailerons are
the control surfaces attached to the trailing edge of the wings. It helps the
aircraft to move along the lateral axis or about the longitudinal axis. This
movement is known as roll movement. In roll movement one wing goes up and one
wing goes down. The aileron of down going wing goes up increasing the drag and thus
its respective wing does down due to loss of lift. Meanwhile the aileron of up
going wing goes down increasing the camber of its respective wing which make
the wing go up due to increase in lift (due to increase in camber). In this way
the aircraft roll towards the down going wing.
2. Elevator
Elevators are
the control surfaces that are attached to the trailing edge of the horizontal
stabilizers. It helps the aircraft to move along the longitudinal
axis or about the lateral axis. This movement is known as pitching movement.
When the aircraft has to pitch up the elevators move up and vice versa for
pitch down.
3. Rudder
Rudder is the
control surface that is attached to the trailing edge of the vertical
stabilizer. It helps the aircraft to move about the
normal axis. This movement is known as yaw movement. When the aircraft
has to turn left the rudder is moved to the left and vice versa when the
aircraft has to turn right.
Primary control surfaces are
important for normal flight control of aircraft. Loss of control of primary
control surfaces or loss of primary control surfaces can have catastrophic results.
So primary control surface are of prime importance to the aircraft.
WATCH THE FOLLOWING VIDEO TO KNOW ABOUT PRIMARY CONTROL SURFACE OF
AIRCRAFT: