The ailerons, located on the trailing edge of the wings, are the primary control surfaces that control the roll of an airplane.
How Ailerons Work:
- Differential Movement: When the pilot moves the control stick or yoke to the left or right, the ailerons on each wing move in opposite directions.
- Increased Lift: The aileron on the side the pilot is rolling towards moves upward, increasing lift and causing that wing to rise.
- Decreased Lift: The aileron on the opposite side moves downward, decreasing lift and causing that wing to drop.
- Rolling Motion: This differential lift creates a rolling moment, causing the airplane to rotate around its longitudinal axis, resulting in a roll.
Other Factors Affecting Roll:
While ailerons are the primary control, other factors can also influence roll:
- Rudder: The rudder, located on the vertical tail, can also contribute to roll, particularly at low speeds or during turns.
- Spoilers: Spoilers, located on the top of the wings, are used to reduce lift during landing or to help control roll in turbulent conditions.
- Dihedral: The angle of the wings, known as dihedral, can also influence roll. A positive dihedral (wings angled upward) provides inherent stability, making the airplane naturally resist rolling.
Examples:
- Banking into a Turn: When a pilot banks an airplane into a turn, the ailerons are used to create the necessary roll.
- Correcting a Skid: If an airplane begins to skid, the ailerons can be used to correct the roll.
