Apparatus And Method For Aerodynamic Blowing Control Using Smart Materials

Abstract

A method and apparatus for controlling the blowing of compressed air from an aerodynamic structure such as an aircraft wing or helicopter rotor blade and thus controlling the aerodynamic properties of the wing comprises a narrow slot (13) in the upper surface 915) of the structure near its trailing edge (14). Inside the wing (12) is a chamber (23) that is connected to the narrow slot (13) in the wing surface (15). The chamber (23) houses a compressed air conduit (16) for supplying and holding compressed air. A passageway (25) connects the conduit (16) to the slot (13) in the upper surface (25) of the wing (12). The lower wall (27) of the passage (25) has a slit (32) allowing a shutter (31) to move selectively into the passage (25) and obstruct the flow of compressed air through the passageway (25). The shutter (31) is attached to a smart material actuator comprising a piezoelectrical bender (29). When a control voltage is applied to the bender (29), the bender (29) will bend. The bending of the bender (29) causes the shutter (31) to move up into the passage (25) and obstruct the flow of compressed air. In this way, the flow of air out of the slot (13) in the wing surface (15) may be dynamically controlled by application of selective control voltages to the bender (29).