Abstract: A method of superplastically forming a metal article and an article formed by such a method are provided. The method includes the steps of placing sheet material including at least one sheet of superplastically formable material (2, 3) and a sheet of reinforcing material (10) adjacent a said sheet (2) of superplastically formable material within a mold tool having a male former (18) protruding from the tool surface positioned to contact the sheet of reinforcing material during forming and causing the at least one superplastically formable sheet (2, 3) adjacent the reinforcing sheet (10) to be superplastically formed into conformation with the surface (28) of the mold tool and simultaneously to urge the sheet of reinforcing material (10) against the male former (18).

Abstract: A ring laser gyroscope in which RF excitation is used to cause gas discharge as opposed to DC excitation which is used in conventional ring laser gyroscopes. External surfaces of the body of the ring laser gyroscope are metallized to form electrodes and an RF signal is capacitively coupled to gas reservoirs forming part of the lasing cavities.

Abstract: A projectile, which spins in flight about a spin axis, including a source of pressure fluid, efflux outlet means in flow connection with said source, the efflux outlet means comprising at least two nozzle members symmetrically spaced about the spin axis, each nozzle member being pivotally mounted on the projectile, and means responsive to the prevailing spin rate effective to pivot the nozzle members such that the effective radius centred upon the spin axis at which the thrust generated by the efflux from the nozzle members is operative can be varied whereby the torque applied to the projectile about the spin axis can be varied without the necessity of measuring the spin rate or effecting throttling of the efflux.

Abstract: The diffusion bonding of aluminum and aluminum alloys presents problems because, when left exposed to the atmosphere even for a short time, they acquire an extremely tenacious surface oxide layer that inhibits or prevents satisfactory diffusion bonding. Unlike titanium, this oxide layer is not absorbed at diffusion bonding temperatures. The present invention comprises a method of reducing oxidation of a surface of aluminum or aluminum alloy by causing a nitride film to form on the surface. This film is believed to prevent oxidation of the aluminum or aluminum alloy, but to be absorbable into it at diffusion bonding temperatures. In the preferred embodiment shown in FIG. 1, the nitride film is applied to the piece of aluminum or aluminum alloy (10) in a vacuum chamber (4) by sputtering with nitrogen ions, or by heating the piece (10) in a nitrogen gas atmosphere.

Abstract: A jettisonable adaptor for air-carried missiles is located between an aircraft-mounted launcher and a missile. The adaptor may include flight stabilization and retardation functions which are deployable on separation from the launcher. Instead of mounting fixing hooks on the missile (which would incur aerodynamic-drag) these are mounted on the adaptor instead. When stabilization has occurred the adaptor is separated from the missile.

Abstract: A guided missile for air to ground deployment having a modular construction which can be readily configured to suit varying deployment roles. The missile comprises a common central fuselage 1, 2, 3 carrying a fuel tank and mounting points for an engine, wings and nose-cone 7. Bolted onto either side of the fuselage are panniers 6a, 6b of variable length and payload capacity. In one embodiment the panniers 6a, 6b carry munitions for lateral ejection through frangile panels. In an alternative embodiment, munitions are mounted in the fuselage and the panniers carry fuel.

Abstract: An aircraft wing, a fusion bonded thermoplastic fixed leading edge structure for aircraft aerodynamic surfaces and a method of manufacture are provided. The fixed leading edge structure comprises a leading edge skin (28), one or more aerodynamic profile defining stiffening members (17, 18) spaced spanwise therewithin and a sub-spar. Each of the components are of low modulus consolidated composite material and the leading edge skin (28) is attached to the stiffening members (17, 18) and to the sub-spar by a fusion-bonding thermoplastic process.

Abstract: This invention relates to a process of forming components having selectively thickened regions from superplastically formable and diffusion bondable materials. The said selected thickening is achieved by positioning metal matrix composite plies between the interior surface of each of the formed skin sheets of the component and the sheets which will form the internal cells, superplastically forming the cells, and then diffusion bonding the component to form a metallurgically bonded structure.

Abstract: Described herein is a method of manufacturing components having "warren girder" or "X" core structures, i.e. those having internal support walls extending between their outer surfaces, from superplastically formable and diffusion bondable materials having different flow stress characteristics. By using materials of relatively high flow stress characteristics for the outer skin sheets of the component, and relatively low flow stress characteristics to form the internal support walls, the tendency for the sheets outer skin to bow outwards during superplastic formation at a faster rate in regions where they are the greatest distance from support walls is reduced. Consequently, the exterior of the outer skin sheets is less susceptible to the formation of recesses thereon at the point where the corresponding interior surface meets the inner support walls, i.e. the phenomenon of quilting is substantially eliminated.

Abstract: A process is disclosed of explosive bonding two or more components together by forming the components into a stack, placing the stack into an envelope made of a deformable material, sealing the envelope except for an evacuation port, evacuating the interior of the envelope through the said port and subjecting the stack to explosive bonding within the envelope, thereby joining the components together; by conducting the explosive bonding in an evacuated envelope, not only are the components protected from damage during the explosion but the bonding is enhanced due to the reduced pressure of air between the components. After bonding, the stack can be subjected to superplastic forming.

Abstract: A swept forward wing for aircraft comprising an inner wing portion and an outer wing portion in which the upper surface curvature of the inner wing portion is designed to create three dimensional flow thereover to manipulate the sweep of the isobars and prevent desweeping thereof, the inner wing portion including a wing root section (4) having a far aft maximum thickness position (14) coupled with high camber in the region of said maximum thickness position, said wing root section (4) further including a negatively cambered leading edge portion (10) and a nose-down twist configured to suppress high leading edge velocities, the combination of thickness and camber forms aft of the leading edge region (10) causing the flow to accelerate until a maximum velocity is reached relatively far back on the wing.

Abstract: A digital chirp generator for generating linear frequency modulated signals, comprises a plurality of frequency/phase accumulators pipelined together. Each frequency/phase accumulator includes a frequency accumulator driving phase accumulator. In the pipelined configuration the frequency accumulator and the phase accumulator of each frequency/phase accumulator are interconnected with the corresponding frequency accumulator and phase accumulator adjacent of the frequency/phase accumulator.

Abstract: Locking bolt assembly comprises a bush (9) fixed in use with respect to a structure to which a bolt of the assembly is to be engaged and a socket (1) carried on the bush (9) and provided with locking means (6) for preventing rotation of the socket (1) on the bush (9) but permitting limited longitudinal movement thereon. The bolt is threaded and has a head (3) dimensioned for rotational locking engagement within socket (1). A coil spring (7) urges the head (3) and socket (1) into rotational locking engagement. In use the socket (1) may be moved longitudinally with respect to said bush (9) against the action of the spring (7) from a position in which the head (3) and the socket (1) are radically locked, to a position in which the head (3) is freed for rotation and engagement with a co-operating nut fixed to the structure.

Abstract: Apparatus for and a method of digital signal processing utilises a technique known as sub-band decomposition and reconstruction. A plurality of input channels are provided each of which is mixed with a vernier frequency correction. In a multiplexer implementation, a fast fourier transform (FET) weighted overlap-add demultiplexer is provided for decomposing each input channel into sub-bands. The sub-band outputs are decimated by a factor to the common input sampling rate of a multiplexer, the sub-bands from each channel then being passed into the appropriate ports of an FFT weighted overlap-add multiplexer by a switch matrix. The multiplexer reconstructs the individual channels, interpolates each channel up to the output sampling rate of the FDM signal, mixes each channel up to its assigned carrier frequency in the frequency division multiplexed (FDM) (FDM) and multiplexes the channels. This provides a computationally efficient architecture with the flexibility to accommodate channels of differing bandwidths.

Abstract: A corrosion sensor (1), apparatus for detecting corrosion of a surface incorporating the sensor, a structural assembly (1,21) incorporating the sensor and method for detecting corrosion of a surface employing the sensor are provided. The sensor comprises a thin flexible non-conducting substrate (18) for attachment to a surface subject to corrosive influence and an array of at least two thin flexible metallic electrodes (2,3,4) carried on the substrate wherein the electrodes are disposed closely adjacent one another so as to permit the generation of electric current by electrochemical action therebetween upon corrosion of the electrodes.

Abstract: A vibrating surface gyroscope includes a piezoelectric resonator 10 of material arranged to have a plurality of poles 12, 14 of opposite sense or polarity disposed around the sensing axis. The resultant bi-directional (forward and reverse) poling establishes the mode and modal position of a vibration in the resonator 10. One surface of the structure includes a surface electrode having a surface resistivity comparable with the reactance of the piezoelectric material adjacent resonance so that a bridge circuit can be made up of the electrode and the piezoelectric material. A wideband closed loop system provides feedback into the bridge to maintain it at balance and provides rate output. Scale factor compensation techniques are also disclosed as well as alternative electrode arrangements.

Abstract: The power or frequency characteristics of a layered frequency selective surface assembly (1) having a dielectric substrate layer (2) and, superimposed therewith at a spacing (X) therefrom, at least one layer (3) of electrically conductive elements (4) disposed in an array, is modulated by moving at least one layer (2, 3) relative to the or each other layer (2, 3). The layers (2, 3) maybe substantially planar or substantially non-planar and may be disposed substantially parallel to one another. Relative movement between the layers (2, 3) may retain the substantially parallel orientation or may not retain the substantially parallel orientation. The relative movement may have the effect of changing the spacing between the layers (2, 3) for example to tilt, skew or rotate one layer relative to the or each other layer.

Abstract: An automatic target tracking system comprising video means, target tracking means, correlation means and aimpoint location means which predicts the subsequent position of a target after each viewing by the video means and then correlates this with the actual viewing of the target position so as to estimate that position within a given field of view.

Abstract: A seal (5) suitable for sealing a door (3) to an aircraft fuselage (1) and which also acts as a rain channel when the door (3) is open. In one embodiment the seal (5) is of unitary construction and made from high tear strength silicone rubber. It comprises a flange region (7) for attachment to the fuselage (1) and a hollow compressible bulb (8) which connects the flange (7) with a pair of sealing lips (9,10). The invention has the advantage of providing an effective seal for doors having uneven inner surfaces.

Abstract: A device and method of manufacturing a jointing together cylindrical bodies, in which one of the bodies is composed of two semi-cylindrical shells. Each body is provided with a flanged end which are locked against one another by a threaded clamping ring having a bevelled face 8. In an alternative embodiment, the clamping ring comprises a tapered circlip. The method is especially useful for the jointing together of the various cylindrical parts comprising a missile.