Patent GB-372082-A (GB)
Title: Improvements in and relating to stabilizers for flying boats
IPC: B64C35/00
Filed: 1931-04-23
Abstract: 372,082. Flying boats ; alighting gear. BLACKBURN AEROPLANE & MOTOR CO., Ltd. and RENNIE, J. D., Seaplane Base, Brough, near Hull. April 23, 1931, No. 12037. [Class 4.] The wing floats of a flying boat are mounted so as to permit of fore and aft swinging movements and are controlled by means of cylinders and pistons interconnecting the wing and float, means being provided to admit fluid pressure to the cylinders for raising or lowering the float. The suspension system of the float comprises fore and aft pivoted struts 17, 18 arranged in sets of three of which the centre is in the plane of symmetry of the float and the outer diverge toward twin wing attachments. Fig. 3 shows diagrammatically a hydraulic actuating apparatus including a diagonally arranged cylinder 19 pivotally connected to the wing and containing a piston 20 pivotally attached to the float, the system comprising means for admitting pressure fluid to one side or other of the piston as required. A fluid pump 22 driven by the engine normally circulates oil in a system comprising a reservoir 21, conduits 23, 33 and a relief valve 32 from which a conduit 24 in which is placed a gauge 26 leads to a control valve 25. A conduit 28 leads from the control valve to the upper ends of the cylinders 19 and a conduit 29 to the lower ends thereof via a balance valve 30. The control valve, Fig. 4, normally prevents communication between the conduits 24, 28, 29, and may be operated to establish communication between conduits 24, 28 and between conduits 29, 27 or between conduits 24, 29 and conduits 28, 27 according to whether it is desired to pump oil to the upper or lower ends of the cylinders 19. The valve unit comprises an inlet 124 connected to conduit 24, an outlet 127 connected to conduit 27 and ports 128, 129 connected to conduits 28, 29, respectively. Ports 128, 129 are normally cut off from inlet 124 and outlet 127 by spring-loaded valves 41 .. 44. These valves are operated by a shaft 34 cut away at 35 in the manner shown in Figs. 5 and 6 to form valveoperating cam surfaces, one of which is interposed between the stems of valves 43, 44, and the other between hook-shaped abutments 141, 142 on valves 41, 42 respectively. Packing pieces 36 prevent passage of oil direct from inlet 124 to outlet 127. Rotation of shaft 34 clockwise causes valves 41, 44 to open, permitting oil to flow from the pump to the upper end of cylinder 19 and also permitting the oil displaced from the cylinder by downward movement of piston 20 to flow through conduits 29, 27 to the reservoir 21 ; the reverse action takes place when the shaft 34 is turned anticlockwise in which case valves 42, 43 are opened and oil flows to the underside of piston 20. Means are provided to ensure that the two floats are moved at the same speed, these comprise a valve which is arranged to shut off the supply of oil to the cylinder of the faster moving float. Rotation of the struts 18 of the starboard float, Fig. 3, is arranged to rotate a sprocket 4S connected by chain gearing with a sprocket 138, Fig. 7, keyed to shaft 38 of a piston valve 39 slidably and rotatably mounted in a cylinder 40. Similarly rotation of the struts 18 of the port float causes rotation of a sprocket 238 in screw-threaded engagement with shaft 38. The sprockets 138, 238 are held against axial movement and the normal position of valve 39 is such as to permit oil to flow from inlet 229 to outlet ports 131, 231 associated with port and starboard floats. If the floats move at the same speed, sprocket 238 turns at the same speed as shaft 38 but any difference in speed causes relative movement between these two parts and therefore axial movement of shaft 38, which movement is arranged to bring valve 39 over the port associated with the faster moving float. Cylinders 19 may be of the self-sealing type, Figs. 9 and 10. The cylinder has inlet ports 228, 231 communicating with conduits 28, 31, respectively. These ports are normally maintained closed by spring-loaded valves 62, 63, respectively. Valves 62, 63 carry pistons 162, 163 at the ends of their stems. If oil is forced into the cylinder by the conduit 28 the valve 62 is opened by the pressure of the incoming oil acting directly on its head and the valve 63 is opened to permit oil to escape from the other end of the cylinder by the oil pressure on the associated piston 163 which is communicated by a pipe 65. The reverse occurs when oil is forced through conduit 31. When the supply of oil to the cylinder is interrupted valves 62, 63 close automatically sealing in the oil above and below the piston. An indicator 52, Fig. 3, driven from the shaft operating the balance valve is provided to show the position of the floats. A handpump may be provided in the system for use should failure of the pump 22 occur. The drawings show a nacelle carrying the pilot's post mounted on the upper centre section of the cellule. A method of operating the retracting gear by compressed air acting on oil columns is referred to in the Provisional Specification and it is stated that the compressed air may be employed not only for actuating the retracting mechanism but also as an elastic medium for absorbing shocks on alighting.