GB596367A - Improvements in airfoils - Google Patents

Abstract

596,367. Aerofoils. GRISWOLD, R. W. May 23, 1944, No. 9925. [Class 4] An aerofoil has a leading edge slot formed by a relatively large entrance passage in the lower portion of the leading edge for the admission of air into a chamber within the aerofoil, and a relatively small nozzle-shaped discharge slot or slots disposed rearwardly of the leading edge slot and discharging air from the chamber through a downstream portion of the aerofoil, the aerofoil sections being pivotally connected and their adjacent edges defining the discharge slots. Fig. 7 shows a construction comprising three sections 39, 33, 41 articulated to a forward section 19, the interior of which forms the pressure chamber 24 with the opening 23 in the leading edge. The discharge slot 32 is formed between the upper trailing edge 16 of the section 19 and the leading edge of the portion 39. The lower surfaces of the sections 39, 33, 41 are of air-permeable material, the air being discharged through slots 40, 44 between the upper surfaces of the sections. The discharge slots control the boundary layer over the upper wing surface, and also furnish a propulsive thrust. Fig. 8 shows an arrangement in which a heat-exchanger 111 is provided in the chamber 82 to increase the velocity of discharge through the slot 73. The exchanger may be supplied from the engine exhaust. The wing sections are capable of cambervarying movements, either manually or under the influence of air gusts, under the action of the control linkage forming the subject of divisional Specification 596,424. In the construction according to Fig. 18, the front opening 167 communicates with the pressure chamber 166 through a divergent throat 169, and a bleeder slot 180 is provided in the lower surface of the forward wing section 170 for boundary layer suction.