Abstract: An aircraft having a powerplant with an aft-directed main propulsion outlet means for providing forward thrust, and further including duct means having an inlet for receiving at least a proportion of the efflux from said main propulsion outlet and extending forwardly to an auxiliary outlet disposed adjacent or forwardly of the centre of gravity of the aircraft, said auxiliary outlet being arranged to exhaust efflux with at least a vertical component.

Abstract: An aircraft carrier is provided with an airflow deflector such as flap 26, an inflatable flap 26 or an airjet curtain such that air passing along the flight deck is provided with an upward component of velocity, thereby to provide an upwash in the airwake behind the aircraft carrier. The upwash persists for a reasonable length downstream of the aircraft carrier and means that, for a given spatial attitude, the angle of attack of the aircraft relative to the airstream is increased. This means that the aircraft may be flown at a reasonably high angle of attack to the airstream on a landing approach without sacrificing the pilot's view of the deck. In addition, the increased angle of attack may be used to facilitate a flare maneuver.

Abstract: A lift arrangement for conveying a load between two levels in a lift shaft, said lift arrangement comprising two platform means each mounted for movement within said lift shaft between one level and the other, each platform means being changeable between a load-carrying configuration in which it extends across a substantial extent of the lift shaft, and a bypass configuration in which it allows the other floor means to pass it when in a load carrying configuration.

Abstract: An inlet gas mixing element for a gas turbine engine, comprising a gas intake duct 10, and downstream of the inlet duct a mixing element 22, the mixing element being so disposed in relation to the inside of the duct so as to rotate thereby urging the forced mixing of the air and other gases moving past the element 22 towards the face of the fan blades of the downstream engine compressor stage 16. The action of the mixing element serves to increase the mixing of new air and other possibly hotter gasses so as to reduce the temperature differential across the face of the engine compressor stages.

Abstract: An inlet gas mixing element for a gas turbine engine, comprising a gas intake duct 10, and downstream of the inlet duct a mixing element 22, the mixing element being so disposed in relation to the inside of the duct so as to rotate thereby urging the forced mixing of the air and other gases moving past the element 22 towards the face of the fan blades of the downstream engine compressor stage 16. The action of the mixing element serves to increase the mixing of new air and other possibly hotter gasses so as to reduce the temperature differential across the face of the engine compressor stages.

Abstract: Apparatus for the control of boundary layer fluids by a suction technique, the said apparatus being adapted to form part of or attach to a fluid dynamic surface and comprising; a sandwich skin material consisting of at least two layers, an outer layer of which is in use positioned adjacent to the boundary layer fluid, the said layers of material bounding internal intercommunicating passageways to allow in use the movement of fluid to substantially all areas within the material, the outer layer being provided with a plurality of holes communicating with the internal passageways of the said sandwich skin material and a plurality of hoods or steps being fixedly attached to the outer layer of the material located such that in use said hoods or steps are downstream of said plurality of holes and each upstream of and shielding an opening in said outer layer and communicating with at least one of said internal intercommunicating passageways.

Abstract: The invention concerns nozzle control apparatus for VSTOL aircraft power plant having at least one vectorable thrust nozzles 22. The apparatus comprises oscillating means for oscillating the nozzles about a generally vertical axis (at least) so as to enlarge the area 30 affected by the exhaust gases 25, 26 from the nozzles 22 during hovering and/or landing.In the prior art, the hot jet 26 impinges on a relatively small area 30 of the surface 12 which area rapidly exhibits erosion effects; it has been found that the erosion is generally proportional to the local rate of heating, with a surface time constant of a few seconds. Accordingly, ground/deck erosion is alleviated by spreading out the jets 25, 26 and especially the latter to increase their `footprint`, i.e. if the area 32 of the surface 12 being heated is enlarged.

Abstract: An aerodynamic or hydrodynamic surface having a swept-back leading edge includes at least one flow separation device located on an attachment line of the leading edge, such as a step-up, step-down, fence or gap. The flow separation devices are preferably arranged normal to the leading edge and are dimensioned so that span-wise turbulent air flow is re-laminarized downstream of the devices thus reducing skin-friction and greatly improving the aerodynamic or hydrodynamic efficiency of the surface.

Abstract: A device for indicating changes in the state of charge of a rechargeable battery including a current sensor to sense current flow into and out of the battery and to provide an output indicative of both the magnitude and direction of the current flow, a timer to provide a timing signal, and a computer programmed to compute from the output of the current sensor and the timer, a signal representative of the charge dissipated from or accumulated in the battery over a period of time. Preferably the device includes data storage to store an indicatioin of the state of charge of the battery and the computer is programmed to use the signal to update the stored data to provide an indication of the current state of charge of the battery.