GB645474A - Improvements in or relating to aircraft - Google Patents

Abstract

645,474. Boundary layer control ; screw propellers. STALKER, E. A. Oct. 16, 1946, No. 30803. Convention date, Jan. 12. [Classes 4 and 114] The boundary layer is sucked from the surface of an aircraft by a blower driven by a windmilling propeller, the blades of which may be retracted into a position clear of the airstream. In the form shown in Figs. 1 and 4, the propeller 22 is carried by a shaft 24 to the rear of the wing 6, the blower 20 being driven through bevel gearing 36. The propeller blades 26 are operated by a rack 48 which engages toothed sectors 50, 52, the rack being moved by a hand pump 36 controlling the supply of liquid to a cylinder 38 in which moves a piston rod 42. In the case of a jet-propelled aircraft the propeller may be mounted at the tail of the jet nozzle, the blades 52 being retracted into recesses 54 at the end of the fuselage, as shown in Fig. 5. With such an arrangement the propeller may be coupled to the compressor-turbine unit at take off through a shaft 109, clutch 106, and gearing 110, 105, Fig. 7. Each blade is moved to and from its retracted position by an electric motor 72, shaft 74, bevel gearing 76, 78, screw and sleeve 82, 84, and a link 86. Pitch control is effected by hydraulic rams 88, 90, the movement of which causes sliding of a sleeve 94 and rotation of a shaft 96 through helical slots 97, the shaft 96 carrying a bevel pinion meshing with a second pinion 98 on the hub arm 58.