Abstract: A venturi section or cone for a lightweight firearm such as a recoilles gun which is subjected to high transient pressures and temperatures on firing is formed from a resin impregnated multi-filament fiber material. The material in the form of an elongated tow is wound on a mandrel, cured, and then removed from the mandrel for subsequent operations such as machining or assembly. During manufacture, a hot gas erosion preventing layer is first formed on the mandrel and a plurality of layers of two are helically wound thereon at a helix angle selected to provide adequate axial and hoop strengths for resisting axial thrust and hoop loads produced on firing. Lightweight recoilless guns using such venturi cones are lighter and cheaper to fabricate than conventional guns and will fire more rounds before excessive erosion causes them to be unusable.

Abstract: The thermal deformation of an edge-restrained plate is expressed as a deflection of the plate out of its plane. Where the plate is used as a reference plane, the deformation of the plate can be quantitatively monitored and compensated for. In the case of a radiantly heated plate, the temperature gradient adjacent an edge of the plate is a linear function of the plate deformation. With convective cooling, the temperature drop from an initial condition relates linearly to deformation. Consequently, relatively simple temperature measurements will provide the necessary information. The invention has particular application to the roof of a military tank turret that is used as a reference plane for a gun sighting system.

Abstract: A barrel section for a lightweight firearm such as a recoilless gun which is subjected to extremely high transient internal pressures and temperatures on firing is formed from an epoxy-resin impregnated carbon fibre material. The material, in the form of an elongated tow is wound on a mandrel, cured and then removed from the mandrel for subsequent operations such as machining and assembly. During manufacture, a gas-erosion preventing layer is formed on the mandrel and a plurality of layers of tow are helically-wound thereon at a helix angle .theta.=tan.sup.-1 (.sigma..sub.axial /.sigma..sub.hoop) where .sigma..sub.axial and .sigma..sub.hoop are the axial and hoop stresses produced in the barrel section by axial and hoop loads respectively. Lightweight recoilless guns using barrels in accordance with the invention are lighter and less costly to fabricate than conventional guns and are capable of firing upwards of 30 rounds before excessive erosion causes the firearm to be unusable.