Abstract: A suspension arrangement for use with aircraft landing gear, including an upper strut, a lower strut that is assembled with and telescopes relative to the upper strut and an oil reservoir within the struts. An adjustable valve assembly includes two interacting relatively movable members which divide the oil reservoir into two distinct sections and provides a restricted flow path for the flow of oil from one section of the oil reservoir to the other. Each of the relatively movable members includes apertures for the flow of oil from one section of the oil reservior to the other thereby to provide that flow path, the aperture being a series of windows in one member registrable with ports in the other member. A drive motor is mounted internally within at least one of the struts and moves the adjustable valve assembly so as to adjust the flow path area, which thus varies the flow of oil through the valve assembly and thereby varies the response of the suspension arrangement.

Abstract: A hydraulic shock absorber suitable for use with an aircraft landing gear which includes: a first casing member telescopically and sealingly engaged with a second casing member, the second casing member having a first section of reduced diameter in comparison to a second section; and an oil reservoir defined by the first and second casing members, which is divided into two distinct volumes by a one way restrictor attached to the second casing member. The volume of the oil reservoir defined by the first casing member and the first section of the second casing member is further divided into two sections by a two-way restrictor.

Abstract: A propeller blade assembly which enables the mounting of a propeller blade in a hub assembly includes a bearing arrangement that circumferentially surrounds and engages with a section of the propeller blade. The bearing arrangement comprises an inner race assembly of angular contact bearings, and an outer race assembly of roller bearings. The roller bearings being arranged so that the axis of rotation thereof is substantially parallel to the longitudinal axis of the propeller blade.

Abstract: A bladed rotor assembly comprising:a bladed rotor;an actuator for effecting a change of blade pitch;a first valve member connected to, and movable with, the actuator and having first and second passageways;anda second valve member co-operable with the first valve member and having first and second passageway systems formed therein for communication with the first and second passageways of the first valve member.The first passageway system of the second valve member includes first and second independent passageways, and is provided with a valve, and a bypass incorporating a non return valve. The valve is positioned so that when in a closed position fluid is prevented from entering the first independent passageway.

Abstract: A bladed rotor assembly and a control means therefor, which comprises a bladed rotor, a fluid-pressure-operable actuator for effecting a change of blade pitch, a first valve member connect to, and movable with the actuator and a second valve member co-operable with the first valve member, both valve mebmers having fluid passageways therein for supplying fluid to the actuator, and override means being provided to control the position of the second valve member relative to the first valve member, wherein safety means are provided to cause, in the event of failure of the over-ride means, the actuator to effect increased blade pitch.

Abstract: A counterrotatable bladed rotor assembly drivable by a rotatable shaft comprises a leading propeller, a trailing propeller, and a gearbox located axially between the two propellers and enclosed by a non-rotatable casing having an end for attachment to a support structure. The gearbox has a first output shaft to the leading propeller and a second output shaft to the trailing propeller. A first fluid-pressure operable actuator is provided to vary the pitch of the blades of the leading propeller, and a second fluid-pressure operable actuator is provided to vary the pitch of the blades of the trailing propeller. In addition passageways are provided to connect the first and second actuators to a source of fluid under pressure. The casing rotatably supports the second output shaft at a position between the gearbox and the leading propeller and rotatably supports the first output shaft at a position between the gearbox and the trailing propeller.

Abstract: A variable-pitch bladed rotor including a plurality of blades extending outwardly from a hub in which they are each mounted by a respective ball-screw device. Each device comprises inner and outer races each provided with at least one helical groove, a plurality of balls co-operable with the grooves, and a cylindrical cage disposed between the races which is suitably apertured for accommodation of the balls. The cage supports gearing so associated with the inner and outer races that on pitch-change movement of the respective blade the cage is positively driven, thereby to turn about the blade longitudinal axis.

Abstract: This invention relates to a method of making a foam-containing structure which includes placing and suitably retaining a respective first shaped sheet in each of first and second complementary parts of an open mould. Each sheet includes at least one layer of fibrous material. A further respective shaped sheet is placed and suitably retained upon each first sheet. Each said further sheet comprises a layer of fibrous material and an impervious membrane adhering thereto. When the two mould parts are closed together a foamable material is introduced into a cavity formed between the sheets and is then caused to expand, whereupon each membrane is caused to adhere to its adjacent first sheet but prevents penetration of the expanding material into that sheet.

Abstract: Ths invention relates to a method of making a foam-containing structure which includes placing and suitably retaining a respective shaped sheet in each of first and second complementary parts of an open mould. Each sheet includes at least one layer of fibrous material and on that face thereof remote from the respective mould part at least one filter layer. When the two mould parts are closed together a foamable material is introduced into a cavity formed between the sheets and is then caused to expand. Some of the expanding material passes through the filter layers into the fibrous material, the characteristics of those layers being so chosen as to produce a desired extent of penetration of the expanding material into the fibrous material.

Abstract: A power transfer unit for transferring power between two separate hydraulic circuits comprising a casing, a pair of cylinder blocks in the casing, cylinders within each cylinder block, a piston in each cylinder, a leakage chamber within the casing, cam means located in said chamber for causing joint reciprocation of the pistons, pistons or extensions thereof extending from the cylinders to the cam means in the chamber, first valve means co-operating with the cylinders of the first block, second valve means co-operating with the cylinders of the second block, first leakage collecting means for the first valve means separate from said chamber, second leakage collecting means for the second valve means separate from said chamber, and a vent for said chamber separate from said leakage collecting means.By this arrangement any leakage to the chamber may be from either or both circuits and by virtue of the vent may be disposed of rather than fed back to either circuit.

Abstract: Control means, for effecting the pitch-adjustment of a rotor blade, includes an actuator urgeable by biassing means in one direction for adjusting pitch in one sense and being subjectable to fluid pressure for movement in the opposite direction, against the action of the biassing means, for adjusting pitch in the other sense. Stop means is provided which is also subjectable to said fluid pressure, being maintained in an inoperative position when the pressure is above a predetermined value and being movable into an operative position when the pressure falls below that predetermined value. Abutment means is engageable by the stop means, when in its operative position, to arrest movement of the actuator at a predetermined position when moving in said one direction.

Abstract: A rotary actuator, suitable for use with rotors having flow-varying blading, for effecting adjustment of the blading, including two relatively-rotatable and co-axially-disposed main actuator components. Each of the components carries a respective abutment means, one of which is axially-displaceable with respect to its component between an inoperative position and an operative position, and both of which are so disposed with respect to their components that during operation of the actuator with said one abutment means in its operative position, the two abutment means co-operate to arrest relative rotational movement of said components only upon said components reaching a pre-determined relative rotational position.

Abstract: A rotary actuator includes two relatively-rotatable main actuator components, abutment means being carried by the first component and displaceable axially with respect thereto, and further abutment means being carried by the second component. Holding means is operable for holding the displaceable abutment means out of engagement with respect to the further abutment means whereby relative rotational movement between the components occurs when one of them moves in either one of its two directions of rotation. Controlling means is operative, with the holding means inoperative, for urging the displaceable abutment means into engagement with the further abutment means at any relative rotational position of the components.

Abstract: A bladed rotor including a hub which carries, so as to be rotatable therewith, a liquid reservoir, at least one pump operable upon rotation of the rotor, a single liquid-pressure-operable vane-type actuator for adjusting the blades of the rotor to vary flow of fluid over the blades, and control valve means for controlling operation of the actuator. The said pump, when operating, draws liquid from the reservoir and delivers it under pressure, by way of said control valve means, to said actuator.