Abstract: A regenerative pump comprises a housing (1) with a pump inlet (13) and outlet (14), an impeller (5) with a plurality of blades (8) forming a series of cells (9) around the axis of rotation of the impeller, and a flow channel within the housing extending between the pump inlet and outlet and including a guide channel (15) in the housing into which the cells (9) open laterally of the impeller so as to induce a flow of fluid through the flow channel as the impeller is rotated. Each blade (8) extends radially over a first radial portion (20) thereof adjacent to the pump inlet (13) and over a second radial portion thereof adjacent to the guide channel (15) and has a trailing surface (19) with a profile that varies radially. The trailing surface of the blade over the first radial portion (20) is inclined forwardly in the direction of rotation (R) towards its outer edge (17) as compared with the trailing surface (19) of the blade over the second radial portion.

Abstract: A hydraulic actuator system, for use in an aircraft, and in which the servo fluid supply to the system is used to provide for the operation and cooling of the system. The system comprises a hydraulically operated piston mechanism including at least one hydraulically operated piston, a servo vluid input to the system, which is connected in a ring main to a first side of the hydraulically operated piston, a servo fluid output from the system, which is connected in a ring main to a second side of the hydraulically operated piston, a variable restrictor arrangement which provides an interface between the servo fluid input ring main and the servo fluid output ring main, and a restrictor arrangement positioned in the servo fluid output side of the system. The position of the piston of the hydraulic piston and the adjustment thereof, are controlled by the restriction applied on the system by the variable restrictor arrangement.