| 摘要 |
656,020. Aerofoils. NATIONAL RESEARCH DEVELOPMENT CORPORATION. June 11, 1948, No. 15855. [Class 4] [Also in Group VIII] An aerofoil or other article having a laminated skin of moulded synthetic resinous material secured to an inner structure or core is made by interposing a parting agent between the whole or part of an outer lamination 11 of the skin and the whole or part of a next adjacent lamination 16, moulding the skin to shape, displacing the whole or part of the outer lamination, securing the skin to the inner structure or core 23 by securing members such as screws 24 which pass through the inner laminations of the skin, and replacing and glueing down the outer lamination. Alternatively, the planes of weakness may be so produced in the moulding stage that the whole of the leading edge L, Fig. 5, comes away with the outer skin when it is separated from the rest of the moulding. The parting agent may be a sheet of regenerated cellulose or a coating of methyl cellulose. The assembly placed in a mould 12 may comprise a layer 11 of uncured asbestos-reinforced synthetic resinous material, a thin layer 13 of glass fibre cloth, a layer 14 of regenerated cellulose, and a further layer 15 of glass fibre cloth, and sufficient further layers 16 of resin-treated asbestos to make up the required thickness. A porous mat 20 of glass fibre-cloth carrying an embedded electrical resistance network is placed in contact with the assembly, and is followed by a rubber bag 22 which is evacuated prior to heating by heat from the resistance networks and, if desired, from the mould itself. |
