Abstract: A vibrating cylindrical rate sensor (10) is mechanically balanced and mode aligned with respect to the vibrating portion of the sensor (10) by removing material from a vibrating portion of the vibrating cylinder (34) after the drive and pick-off transducers (30, 32, 30a, 18, 20) are fixed to the vibrating portion of the vibrating cylinder (34) of the cylindrical rate sensor (10).

Abstract: A missile (1) suitable for intercepting an airborne anti-tank threat is tethered to a ground station by control cables (9A,9B,9C,10). By altering the tension on the cables (9A,9B,9C) a vectored thrust nozzle arrangement (6,7) is rotated in order to control missile (1) attitude thereby enabling it to intercept an oncoming target.

Abstract: A vibrating structure gyroscope sensing element structure of ring-like or substantially cylindrical form made of ferromagnetic material is actively balanced by applying a variable strength magnetic field across a predetermined section of the circumference of the sensing element structure differentially to shift the resonant frequency of one or the other of the primary and secondary vibration modes (1,2) thereof by an amount sufficient to bring the two mode resonant frequencies into balance.

Abstract: The invention provides a method of testing a metal component (1) for cold compression of the metal when used, for example for fatigue enhancement. The component defines a generally smooth surface (6) and includes a region (22), eg an aperture, subject to cold compression which breaks that surface in a given area. The method includes the steps of placing a moire grid (13, 15) such that it is spaced from and coextends with the said area of the surface, directing a source of generally parallel light (16) through the grid (15), and at an oblique angle thereto, at the said area of the surface, and viewing the surface through the grid substantially normal to the surface whereby to observe any light interferences fringes (24) caused by eruption of the surface due to cold compression of the metal.

Abstract: A thermal picture synthesis device (1) of multi-layer construction has a resistor element (3) spaced from a semi-conductor substrate layer (2). The resistor element (3) is made of titanium or Ni-chrome. A drive element layer (4) is provided either in or attached to the substrate layer (2) for the resistor element (3). By placing the drive element layer parallel to and spaced from the resistor element (3) it is possible to pack a plurality of resistor elements (3) into a side by side adjacent array with a high fill factor or packing density and this coupled with the use of titanium or Ni-chrome for the resistor elements (3) and the spacing of these elements from the semi-conductor substrate (2) allows the device to operate at a higher apparent temperature than is conventional.

Abstract: An optical gyroscope includes an optical fibre ring or coil (2) around which light may propagate in clockwise and counter-clockwise directions, means (1, 3, 4, 5, 6) for inputting a beam of light in either direction into the coil (2), a phase modulator (7) for generating and applying a phase modulation at a modulation frequency between the clockwise and counter-clockwise beams, a detector (8) for detecting the combined clockwise and counter-clockwise beams and processing means for monitoring the intensity of the output of the detector means (8) at a plurality of integral multiples of the modulation frequency to determine the rate applied to the gyroscope.

Abstract: A method of forming a diffusion bonded joint during superplastic forming of a hollow metal structure (43) from sheet material (15, 16, 17, 18) using a two-piece die (1) having opposed clenching faces (9, 10) disposed along a split line (2) thereof, the structure 43 being formed with a joint at the split line, the method including placing the sheets (15, 16, 17, 18) between the faces (9, 10) clenching the sheets with a pressure sufficient to locate same during superplastic forming while being insufficient to deform the metal and prevent superplastic flow in the sheets between the clenching faces (9, 10), heating the sheets to a superplastic forming temperature and applying a gas pressure between the sheets to commence superplastic forming, when superplastic metal flow between the clenching faces substantially ceases upset forging metal from between the faces towards the interior of the die to increase wall thickness at the joint upon trimming off a flange formed by that part of the sheets trapped between the c

Abstract: The attitude of a body 12 is determined, or refined, by illuminating it with a direct beam and one or more indirect beams which are reflected from a scattering surface SS, all of the beams being radiated from the same or adjacent sources. The directions of arrival of the beams are determined to allow the attitude to be determined or refined.

Abstract: A beam expander suitable for use with laser machining apparatus comprises a convex paraboloidal surface 7 and a concave paraboloidal surface 8 formed from a single metal element 10. The expander has an optional zoom facility provided by a plane mirror 12, moveable along an input-output axis, for altering the position of an incident beam on the convex surface 7 thereby altering the magnification of the system.

Abstract: A fastening arrangement for connecting two items comprises a stud 16 secured to one item 14 and a captive fastener 18 located in a fastener body 20 secured to the other item. The captive fastener 18 is made up of a nut 32, a washer 34 and an outer clip 36 for securing the nut to the clip. The nut, washer and clip 36 may all be passed though the access opening 30 in the fastener body when separate, but when assembled, they resist withdrawal.

Abstract: Apparatus, method and an arrangement for rigging an aircraft wing flap are provided. The apparatus (27) is for measuring horizontal and vertical positioning of a trailing edge (21) of a wing flap (14, 15) relative to a flap track beam (6) upon which the flap (14, 15) is mount for deployment movement. The flap track beam (6) is affixed to a wing main torsion box (1) behind which the flap (14, 15) is deployable. The apparatus (27) engages the trailing edge (21) of the flap (14, 15) to allow accurate horizontal and vertical positional measurement of the trailing edge.

Abstract: Apparatus suitable for tracking a road vehicle from an aerial platform uses a correlator (5) for processing data received from a thermal imager (1). The apparatus derives a binary template for use by the correlator (5), the template (13) being based on points of high curvature (12) in an object to be tracked. The invention shows a significant reduction in mistracking and drift compared with conventional correlation trackers under the conditions of high density of features similar in nature to the object of interest, such as typifies the imagery obtained from a ground-pointing camera mounted on an aerial platform.

Abstract: A method of and apparatus for scale factor compensation for piezo-electric rate sensors maintains the magnitude of vibration at a primary pick-off point substantially constant to enable one of the variables of a vibrating structure--the piezo-electric charge coefficient .beta. to be determined, and thereby enables variation of the scale factor of the sensor from a calibrated value to be determined. This enables correction of the sensor output by a computational scale factor control unit to ensure that the output therefrom allows for a more accurate sensor. Thus, sensors are provided for applications requiring a higher degree of accuracy than they were previously able to provide for.

Abstract: A lightning shield comprising a fiber reinforced plastics laminate (13, 14), a fixed leading edge structure (12) and an aircraft wing (1) comprising said laminate shield are provided. The laminate shield comprises a series of laminae (21, 22) of fibre reinforcing material held together by plastics matrix material, the laminate including a layer of electrically conductive material (19) interposed between an outer lamina (21) and its next adjacent lamina (22) for conducting lightning current attaching to the laminate to conducting fasteners (31, 32) passing through the laminate (13, 14).

Abstract: A multi-processing computer system has multiple computing units. Each of the computing units includes a processor linked to a private memory via a private data bus, and each computing unit is linked to every other computing unit by a respective separate independent shared memory area. The shared memory areas are controlled by a communications controller which can provide a fully asynchronous two-way communication route through the memory area. The multitasking capabilities of the computer are further controlled by a set of unit controllers in combination with respective software task schedulers.

Abstract: A missile approach warning surveillance system adapted to operate in the ultra-violet ozone absorption waveband.

Abstract: An aircraft landing gear trolley (1) for supporting a landing gear (2) and adjusting the position of pintle bearings (39, 71) thereof in relation to pintle mountings on an aircraft is provided. The trolley (1) includes a rolling chassis (3) and a number of frames (15, 16, 17, 18, 19) nested therein, each arranged to provide a different degree of freedom for the landing gear (2). The said degrees of freedom include movement along horizontal, longitudinal and transverse axes, raising and lowering movement and rotational movement about horizontal and substantially upright axes. The rotational axes are coincident at a point positioned centrally of one of the pintle bearings (39) of landing gear (2) supported by the trolley.

Abstract: Auxiliary control of extension, retraction and pivotal movement of aircraft landing gear when not in use is provided by a method of operation, apparatus for attaching to the landing gear, and an assembly comprising landing gear and apparatus. The apparatus comprises auxiliary jacking means (18, 19) attachable between relatively telescopic parts of an oleo main strut of the landing gear and between relatively pivotal parts of the oleo and of a bogie pivotally attached to a lower end of the oleo. The landing gear may thus be powered up by the auxiliary jacking means (18, 19) with the pivotal movement of the bogie (4) being controlled simultaneously during, e.g. removal, fitting or servicing of the landing gear.

Abstract: A vibrating cylindrical rate sensor (10) is mechanically balanced and mode aligned with respect to the vibrating portion of the sensor (10) by removing material from a vibrating portion of the vibrating cylinder (34) after the drive and pick-off transducers (30, 32, 30a, 18, 20) are fixed to the vibrating portion of the vibrating cylinder (34) of the cylindrical rate sensor (10).

Abstract: A single axis rate sensor comprising a cylinder positioned about an axis and having primary and secondary drive and pick-off transducers and primary and secondary control loops. The primary control loop is provided for maintaining resonance of the cylinder by generating a ninety-degree phase shift between the primary drive transducer and the primary pick-off transducer. The secondary control loop is provided for receiving a signal from the secondary pick-off transducer indicative of rotation of the cylinder and for nulling the secondary drive transducer to zero. The primary control loop includes a phase-locked loop having a phase detector configured to operate at quadrature. By operating the demodulator in quadrature the demodulator and loop filter combination are a linear device which will not mix the microphonic baseband signal with the carrier. There will therefore be a reduction and possibly an elimination of the modulation of the voltage controlled oscillator by microphonic noise.