Abstract: A joint assembly and an aircraft wing assembly containing such a joint assembly are provided. Each joint assembly for connecting together a first member (1) and a second member (4) comprises a second channel member (5) affixed to the first member (1) having a first channel member (12) with sidewalls (15, 16) engageable with first and second elements (8, 9) of the second channel member. The second member (4) has a flange which engages a flat surface (14) of a base portion (13) thereof. The various elements are held together by bolts (19, 20, 23) and tolerance adjustment in both horizontal and vertical directions is provided by mutual sliding of the surfaces prior to drilling apertures for the bolts.

Abstract: A vibrating structure gyroscope has a vibratory resonator having a substantially ring or hoop-like shape structure, an electromagnetic drive for causing the resonator to vibrate, a support structure including a plurality of flexible support beams for supporting the resonator whilst allowing it to vibrate and an electromagnetic sensor for sensing movement of the resonator. The support beams and resonator are made from silicon and the electromagnetic drive and sensor include metal tracks which extend externally along each support beam onto and along respective segments of an outer substantially planar surface of the ring-like resonator. The resonator is substantially planar and means is produced a magnetic field substantially perpendicular to the plane of the resonator.

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: A non-linear dispersive transmission line includes a plurality of substantially block-like shaped capacitor elements (4) arranged in sequence in at least two arrays. The even numbered elements (4b, 4d etc) extend side by side to form a first array and the odd numbered elements (4a, 4c) etc extend side by side to form the second array. Each element (4) in one array is connected via inductors (3) to two immediately adjacent elements in the other array. Facing surfaces (5) of each two immediately adjacent elements (4a, 4c) in each array form cross link capacitors.

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: A rate sensor for sensing applied rate on at least two axes is provided. A vibrating structure is vibrated in a Cos 2.theta. carrier mode at a Cos 2.theta. carrier mode frequency such that rotation about one or the other of the two axes will generate a Coriolis force sufficient to cause a rocking motion and rocking mode vibration of the vibrating structure about the same axis out of the plane of the vibrating structure at the Cos 2.theta. carrier mode frequency. The vibrating structure has a substantially planar, substantially ring or hoop-like form that is shaped and dimensioned to match the frequencies of the Cos 2.theta. carrier mode and the rocking mode vibration in the vibrating structure to give a resonant amplification of the rocking motion. The rocking mode vibration is proportional to the applied rate. The rocking mode vibration is detected to determine the applied rate.

Abstract: A fiber optic interferometric strain gauge assembly includes a sensor element (1) in the form of a length of single mode optical fiber whose ends (1a) and (1b) have a peak reflectivity not exceeding 10%. This reflectivity is provided either by semi-transparent coating on the fiber ends or by the establishment of Bragg gratings within the fiber length. A laser source (2) provides a beam which is coupled into the element (1) as one arm of an interferometer. The light reflected in the interferometer whose intensity varies depending upon the degree of strain applied to the element (1) is detected and separated out into samples corresponding to the frequency of the laser source and to twice the frequency of the laser source with the two values being processed to provide both the magnitude of strain and the direction of strain in the element (1).

Abstract: A method of heat treating an aluminum--lithium alloy is provided. The method includes carrying out a succession of at least two artificial aging steps. The first such step is carried out within a first temperature range and one or more further steps are carried out within successively reduced temperature ranges to promote the precipitation of the .delta.' phase of the alloy.

Abstract: A radar for an aircraft (1) comprises end-plates (4a, 4b) mounted at the tip's of two pairs of aircraft wings (2a, 2b, 3a, 3b). Each end-plate carries a sideways-looking phased array (6) whose beam is unobstructed by aircraft structure. The array can be made to have a large area, thus producing a narrow beam, steerable over a large solid angle. In one embodiment, the end plates (4a, 4b) incorporate fins (5a, 5b) which replace the aircraft fin to afford lateral stability and control.

Abstract: An environment control system which comprises: a cooling turbine drivingly connected to a compressor, means for driving said cooling turbine-compressor combination, and intercooler means, wherein, in a first mode of operation, the working fluid circulates around a closed loop from the compressor to the intercooler to the cooling turbine, thence along a cooling pass to cool equipment or a volume, and back to the compressor inlet, said system including means operable in a second mode of operation to interrupt said loop to cause working fluid to vent to ambient during or after said cooling pass and to introduce further working fluid into said loop.

Abstract: The present invention relates to a method of testing and/or monitoring structural adhesively bonded joints by the introduction of transducers into the stress or strain field effected by the movement of said adhesively bonded joints under load, such that the load transfer characteristics between the bonded materials and the adhesive can be recorded thus allowing the quantification of the integrity of the adhesive bond lines in such joints. The method assesses the integrity of the bond by comparing the difference in maximum and minimum ratios and curve perameters relating to stress and strain with those of the "at assembly" values.

Abstract: A threshold detector circuit (2) suitable for use with a nuclear event detector for sensing an ionising radiation pulse has a high tolerance to ambient temperature fluctuations. The threshold detector (2) comprises an amplifier stage (3) which includes a pair of complementary transistors (Q2, Q3) and a comparator stage (6) which includes a third transistor (Q4) and a voltage reference (7). Temperature compensation is achieved by the addition of a feedback loop (5) in the amplifier stage (3) including a fourth transistor (Q1) whose temperature coefficient is closely matched to that of the third transistor (Q4).

Abstract: A composite laminate, an aircraft skin panel, an airfoil, an aircraft and a method of manufacturing such a composite laminate are provided. The laminate includes at least three layers, namely a first layer of fiber reinforced composite material, a second layer usually metallic and usually forming a surface of the component and a third layer of impact energy-absorbing material interposed between the first and second layers, wherein the second and third layers protect the first layer from impact damage. The method of manufacture involves placing all three layers, including a said third layer of foaming adhesive, in a closed mould and foaming the adhesive to form a component to shape.

Abstract: An optical cross bar switch assembly includes a first lens device (5) in the form of an array of lenslets (5a) operable to receive light from the input optical fiber array (1) in a manner such that the light from each fiber is received and collimated separately by an associated one of the lenslets (5a) with the collimated light from the array (5) being passed to a fan out grating element (3) which angularly diffracts and replicates the light from the input optical fibers.

Abstract: Vibration mode frequencies of a vibrating structure gyroscope sensing element are matched by removing and/or adding a desired variable amount of material from or to the sensing element (1) at at least one point (4) on or in the vicinity of the neutral axis (5).

Abstract: Chiral composite material is made using an apertured plate (2) having apertures (3) therethrough corresponding to the desired locations of chiral elements (4) in the composite material. The plate (2) is located to overlie a substrate (1) with or without the intermission of spacer (10) which may be apertured in correspondence with the plate (2) or which may be ring like in form. The chiral elements (4) are held in position by locating means such as a tab (5) which may be magnetic in, on or associated with the plate (2) and a first layer (8) of liquid host material is placed in the apertures (3) around the elements (4) against the substrate (1), allowed to set and the plate (2) removed. A second layer (9) of liquid host material is then applied to the set first layer (8) and allowed to set to produce the desired composite material.

Abstract: A method of measuring structural defects of a structure including the steps of: a) attaching to the structure at least one structural defect sensor each including a fibre optic cable in turn including a plurality of longitudinally extending optical fibres mounted in a predetermined spaced apart substantially parallel co-planar array, selected fibres having Bragg Gratings located along their length in their surfaces, one side of the array being adapted for attachment to a surface of a structure to be tested, b) coupling to one end of the fibre optic cable of each sensor a light source, and an optical sensor having time domain measuring and multiplexing capabilities, and, c) monitoring a variation of a light parameter measured by the optical detector using time domain measurement to locate the position of a crack along a fibre and using multiplexing for determining from which fibre the light source is being analyzed, and d) monitoring point strains by measuring a characteristic of light reflected from the Bragg

Abstract: A thermal and shock resistant data recorder assembly as an outer container (1) containing an inner container (2) which in turn houses one or more data recorder elements (3). The elements (3) which have a thin conformal coating thereon are encapsulated in an innermost cavity (4) of the inner container (2) in an Ester wax material which absorbs heat when changing from a solid to a liquid. An outermost cavity (8) surrounds the innermost cavity (4) in the container (2) and in turn contains a first insulating material which gives off water vapor when heated to absorb heat. Surrounding the inner container (2) in the outer container (1) is a second insulating material. The Ester wax material is enabled to leak when liquid into the outer container and from thence, if necessary, to the exterior of the outer container. This permits pressure equalization. The first insulating material is provided with a fusible material plug which melts under heat and allows the vapor to escape to the exterior of the assembly.

Abstract: In an open loop rate sensor clockwise (CW) and counterclockwise (CCW) beams from a common source 10 pass in opposite directions around a coil 20 of optical fiber and recombine on a detector 24. A phase modulator 22 applies a stepped phase modulation in which each step is of duration equal to the transit time of the coil 20 and in which alternate steps are zero. The intermediate steps increase linearly from zero to 2.pi.. Without modulation, the CW and CCW beams combine on the detector with a combined intensity which varies as a cosine of rate. The above modulation causes two points to either side of the cosine fringe to be sampled which move progressively farther as the amplitude of the stepped modulation increases. The sample data is processed to determine the rate applied to the rate sensor.

Abstract: An apparatus and method for utilizing the deformation characteristics of optical fiber transmission paths to enable the detection of deformations in materials, in which the fibers are disposed in relation to the material such that each separate deformation in the material lying in the path of the fiber results in a corresponding independently measurable deformation along the length of the fiber.