Abstract: A flexible assembly cell is made up by providing a regular array of fixed, load supporting pedestals on a concrete sub-floor on a meter matrix throughout the assembly area. Jigs and other assembly equipment required in the area are provided with base fixtures on the same meter matrix and the base fixtures are coupled to the relevant pedestals. The gaps between the pedestals are bridged by rectangular load bearing floor panels to provide a raised floor and to provide an underfloor void for routing of services. Moving a jig would be simply achieved by unplugging the relevant services, relocating the jig to a vacant set of pedestals and reconnecting the services, minimising downtime and recurring costs.

Abstract: A non-contacting capacitive position transducer comprises a stator substrate carrying two electrically conducting inverted wedge regions 14,16 whose width varies inversely in a sensing direction. A moveable pick-off 20 is capacitively coupled to both wedges. The wedges 14,16 are driven with respective distinguishable time varying periodic waveforms, e.g. a sine wave and a cosine wave, and the pick-off voltage at 20 processed to determine the position of the pick-off in the sensing direction. Various configurations of transducer are described, including those of linear, cylindrical and disc form. The pick-off voltage is preferably transferred from the pick-off 20 back to the stator by capacitively coupling the pick-off to a suitably screened pick-off track 36 on the stator.

Abstract: The present invention provides a method of forming and a composite superplastically formed structure comprising a panel (40) provided by at least a pair of superplastically-formed sheets (12, 14, 16, 18), which together form a plurality of cells (42), the panel having an opening (20) therein or therethrough defined by a side wall (48) of a respective one, or side walls (48) of respective ones, of the cells; and an insert plug (38) received in the opening and bonded to the said wall or walls.

Abstract: The present invention provides a method of making a frame, particularly for the aircraft industry, having a central member (34) and one or more cantilever ribs (32); such a frame can be made by forging or machining but these are time-consuming and expensive. According to the present invention such frames are made by diffusion bonding and superplastic forming techniques, whereby a pack of sheets are bonded together except in certain areas. Gas is injected into those areas to inflate the pack superplastically to form one or more closed cells (16). The top of the cells is then machined off along line 23, while the side walls of the cells are retained, to provide a frame having cantilever ribs (32).

Abstract: Apparatus for reducing ground erosion caused by impinging hot jets such as the lifting jets of VSTOL aircraft or rockets, said jets emanating from a hot jet nozzle such as a lift engine nozzle or a lift/propulsion engine nozzle, comprising means for introducing a coolant fluid to an impingement surface immediately beneath the turning zone.

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 present invention provides a method of fastening an outer composite aircraft skin (12) to an inner substructure (14), which may be the wall of a fuel tank. The method includes the steps of incorporating an electrically conductive layer (26) in an outer surface of the outer composite skin (12), inserting a bolt (11) through the electrically conductive layer (26) and the outer composite skin (12) and through the inner substructure (14), securing the bolt (11) by means of a nut (22) directly or indirectly engaging the inner surface of the inner substructure (14), and applying insulating material (34) over the head (16) of the bolt.

Abstract: In an infra-red surveillance system, a digital memory (1) has a storage location for each of a number of zones, defined by azimuth and elevation co-ordinates, the zones together covering 360.degree. in azimuth and 20.degree., for example, in elevation. In each location there is stored a data word built up from the responses on a zone in successive scans. Each word can be read into a decoder (5) which selects an appropriate video display level in the form of a two-bit word which is then stored in a buffer store (6). A buffer store data controls the display on a cathode ray tube (2). A manually controlled cursor circuit (8) generates a cursor address which results in a cursor display at the corresponding position on the cathode ray tube. The display is in the form of four strips, one above the other, each representing a quadrant of azimuth.

Abstract: The present invention provides a method of making a frame, particularly for the aircraft industry, having a central member (34) and one or more cantilever ribs (32); such a frame can be made by forging or machining but these are time-consuming and expensive. According to the present invention such frames are made by diffusion bonding and superplastic forming techniques, whereby a pack of sheets are bonded together except in certain areas. Gas is injected into those areas to inflate the pack superplastically to form one or more closed cells (16). The top of the cells is then machined off along line 23, while the side walls of the cells are retained, to provide a frame having cantilever ribs (32).

Abstract: A switching circuit especially suitable for protecting electronic components such as integrated circuits (2) from the harmful effects of ionizing radiation. The circuit comprises two switches for isolating the component (2) from its power supply, the switches conveniently being NPN transistors (TR1, TR2) and being connected either side of a decoupling capacitor (3) associated with a component (2). Because the capacitor (3) is allowed to retain its charge during power-off, no time is lost in recharging it once the power supply has been resumed.

Abstract: A VSTOL aircraft powerplant comprises a gas turbine engine (1), a chamber (2) for receiving exhaust from the turbine section of the engine (1), and a jet propulsion nozzle (3) and vertical lift nozzles (4, 5) connected to the chamber (2). Blocker doors (6, 7) are provided for blocking flow of exhaust from the chamber (2) and thus diverting the flow to the vertical lift nozzles (4, 5). A high pressure air curtain is provided by ducts (9) to control th area of the ports to the vertical lift nozzles (4, 5). Control means coordinate and control the operation of the blocker doors (6, 7) and the air curtain to vary the total efflux between three configurations, namely all efflux occurrng through the jet propulsion nozzle (3) for wing-borne flight; all efflux occurring through the vertical lift nozzle (4, 5) for hovering; and some efflux, which is steplessly variable, occurring through both the vertical lift nozzles and the jet propulsion nozzle for transition between wing-borne and jet-borne flight.

Abstract: A viewing system such as a panoramic sight for a tank, adapted for operation in both the visible and infra-red wavebands, comprising at least one common optical component which is receptive to both types of radiation and a means for subsequently separating the visible and infra-red radiation before reaching direct viewing and indirect viewing apparatus.

Abstract: Apparatus for detecting at least one of the amplitude, frequency and modes of vibration of a panel is described. Detection is achieved using Moire fringes by employing two diffraction gratings (33 and 38) through the first of which light is projected on to the panel. An array of photodiodes (40) is positioned behind the second diffraction grating (38) which receives light reflected from the panel. Signals from the photodiodes are analyzed in conventional ways to produce the required amplitude, frequency and mode information.

Abstract: A cutting tool is provided which comprises a tungsten carbide body or core (2) to which is soldered, brazed or otherwise bonded at least one strip of tungsten carbide (3) that is ground to form a cutting edge or blade. A tough non-vibrating core is thus provided for use with a very hard blade separately replaceable. A method of forming the body or core (2) involves forming a pre-sintered preform, grinding one or more flutes in the preform and subsequently hardening the preform into a fully sintered state ready for use to receive one or more cutting blades.

Abstract: An optical communications system which facilitates rapid establishment of communications between two stations (1, 2). The system uses acousto-optic cells (5, 6) for scanning and frequency modulating a laser beam. The frequency shift introduced by the cell (6) is indicative of the direction of arrival of the beam at a remote station (2). By detecting the shift, the relative positions of the two stations (1,2) may be deduced. The invention is suitable for use with secure communication systems and IFF systems.

Abstract: The pelletisation or granulation of a material or mixture of materials the or at least one of which is reactive in a liquid to produce a gas is improved by treating the reactive material prior to final compaction to form a coating thereon of a substance which is less soluble in the liquid than the reactive material. The preferred reactive material is calcium hydride and the preferred coating is calcium carbonate with or without calcium hydroxide.

Abstract: This invention relates to a composite aircraft comprising a conventional aircraft (2) and a carrier aircraft (4) connected together during flight as a composite aircraft by way of a connector (6). The carrier aircraft has a vertical takeoff and/or landing capability and the conventional aircraft is provided with a directable propulsion nozzle so that during operations as a composite aircraft lift is shared by components of lift from the propulsion systems of both aircraft. Therefore, by connecting itself to the carrier aircraft, the conventional aircraft may takeoff and/or land vertically as the case may be, but without the requirement for a vertical takeoff and/or landing capability of its own and all the weight penalties associated therewith.

Abstract: A fiber optic gyroscope sensing coil having two parts one wound clockwise and the other wound counter-clockwise from a central point on a spool towards ends thereof and back towards the center before crossing over each other and being wound out and back a plurality of times. Such an arrangement has the advantage of eliminating the temperature sensitivity of such coils and reducing microbending of the fibers thereby producing a more accurate coil for a fiber optic gyroscope. Preferably the outermost layer of fiber is a single layer.

Abstract: In a laser gyroscope, a non-reciprocal phase modulation is introduced between the clockwise (CW) and counterclockwise (CCW) beams at a modulation frequency (f). The CW and CCW beams are combined on a detector and the intensity of the output is observed at the fundamental frequency (f) and the higher harmonics (e.g. 2f, 4f). At each frequency, the detected signal is demodulated by mixing it with a reference signal at the same frequency and stepping the phase of the signal through successive increments of 90.degree., thereby to determine the in-phase and quadrature components for each frequency monitored.

Abstract: A ring resonator gyroscope has clockwise and counterclockwise light beams that are frequency shifted by an equal but opposite amount and then have their frequencies varied in antiphase relative to each other about a mean frequency (f.sub.o +f.sub.1 or f.sub.o -f.sub.1) so any backscatter signal is at the difference frequency and locking at zero rate thus is avoided.