GB800380A - Improvements in or relating to intakes for air inspiring apparatus - Google Patents

Abstract

800,380. Axial-flow compressors; gas turbine plant. PLESSEY CO., Ltd. May 4,1956 [May 9, 1955], No. 13294/55. Classes 110(1) and 110(3). An air intake comprises a streamlined inner body provided with member disposed circumferentially about the inner body and expansible for reducing the intake area, the expansible member comprising a number of adjacent long, thin and narrow flexible strips lying on the surface of the inner body with their centre lines in planes containing the axis of the inner body. In the aircraft gas turbine engine shown in Fig. 1, the annular intake d of the compressor a can be constricted by moving an expansible part g from a position in which it follows the outline of an inner wall j to the position shown. The part g comprises flexible metal strips q secured at their forward ends to the inner wall and slidable at their rearward ends h along the inner wall. Fluid is admitted to an hydraulic cylinder m to move a member l from the dotted position, thereby extending the strips q through links k. Preferably a rubber or like cover i is provided. The links may be omitted, the expansion being achieved by moving the free ends of the metal strips in the direction of their fixed ends. In a modification, the members k, l, m are omitted, and the part g is inflated by air or other fluid in accordance with the air speed of the aircraft. The air may be supplied by the compressor. Fig. 3 shows an embodiment in which the expansible part is a metal plate r, the outer portion of which is subdivided by radial cuts into segments q<SP>3</SP> which can be extended into the dotted position by a piston m<SP>1</SP> and links k. A centrifugal pump s driven by the turbine supplies hydraulic fluid at a pressure which varies with the turbine speed and therefore with the air speed of the aircraft by way of a spring- biased flow control valve t<SP>1</SP> and a passage m<SP>2</SP> to the cylinder m. A spill passage m<SP>3</SP> leads back to the pump intake by way of a metering orifice m<SP>4</SP>. An elastic cover similar to the cover i shown in Fig. 1 may be provided.