AILERON, a movable part of the wing of an aeroplane (q.v.) situated at or near the wing tips as shown in fig. 1. They are so connected to the control column that a movement of it, e.g., to the right (or a corresponding rotation of the control wheel), raises the aileron on the right wing and lowers that on the left wing, causing the aeroplane to bank for a turn to the right. Ailerons of the type shown in fig. I are effective in normal flight but when the aeroplane is stalled they become ineffective and a possible source of danger. As the result of research initiated by the Aeronautical Research committee a form of aileron has been developed practically free from this fect. The part of the wing covered by the aileron is "slotted" on the principle inventzd by F. Handley-Page (see AEROPLANE). Fig.
2 shows one form. The universal adoption of some device of this kind is of vital concern to the future of flying, since it will re move one of the most serious risks.
See AERONAUTICS.