GB785721A - Air intake assemblies for aircraft propulsion units - Google Patents

Abstract

785,721. Gas turbine plant. NAPIER & SON, Ltd., D. Feb. 29, 1956 [March 11, 1955], No. 7268/55. Class 110 (3). An annular air intake for a gas turbine engine from the inner wall of which a solid body or nose projects forwardly has a series of movable deflecting members which, in the inoperative position, lie close to and form in effect part of the surface of the solid body or nose and, in the operative position, project from the solid body or nose so as to lie wholly or partially in front of the annular air intake and deflect the approaching air stream and any solid or liquid particles it may contain outwards such that the solid or liquid particles by reason of their momentum pass over the outer edge of the annular inlet opening whilst at the same time leaving between the rear edges of the deflecting members and the outer edge of the annular inlet opening a substantial annular gap through which air can be drawn radially inwards into the opening. A propeller turbine engine has an annular air inlet opening 10 formed between an outer wall 12 and an inner wall 14. A nose portion 15 projecting forwardly from the wall 14 consists of a near stationary portion 16 and a forward part 17 formed by the propeller hub fairing. A series of flap-like deflecting members 18 are hinged to the forward end of the portion 16 and when in the inoperative position lie flush with the surface of the portion 16. The members 18 are in the form of sector plates having one edge joggled. The joggled edge overlaps the edge of the adjacent member. When the members 18 are in the operative position, they spread out fanwise to form a frusto-conical surface spaced from but directly in front of the forward edge 13 of the inlet opening 10. Thus solid or liquid particles carried in suspension in the air approaching the inlet will be deflected outwards with the air and carried outwards beyond the forward edge 13. The air will pass through the gap 33 into the inlet opening. Each deflecting member is actuated by a pneumatic ram 24. The cylinder 25 of each ram is pivoted by a ball and socket joint 26 to an annular member 27 forming part of a channel 28 which may be connected to a source of air under pressure or to drain through a suitable valve. The members 18 are opened by the air pressure in the cylinder and closed by the springs 32 and the air pressure on the members. If desired, the rams may be made double acting. Hydraulic, electrical or mechanical actuators could be used instead of pneumatic rams. The outer surface of each of the members 18 may have a coating of polytetrafluoroethylene or other substance to which ice does not readily cling.