DEVELOPMENT OF COMPOSITE MATERIAL HELICOPTER STRUCTURES

Since the sixties, the composita materials have been a major progress factor mainly leading to a gain in the aircraft empty weight, reduced maintenance costs, and increased safety. The experience gained in the civil and military fields about the composita material parts, presently produced in serine. Is briefly presented as regards manufacture and quality control as well as operational use. Owing to this experience, a general methodology has been set up for the development of composite material parts ; its evolution is described hereafter. Once the selection criteria were specified, the design methods were improved for both computation and laboratory tests ; the manufacturing and inspection methods had to be adapted to these new materials. On the basis of a recent aircraft, the DAUPHIN 2, an analysis of the various composite material parts is presented : the rotor assembly, with its Starflex hub and its new generation blades, the primary structure components containing carbon, the suspension elements, end the secondary parts involving the use of Kevlar. The description of each of these components is followed by a presentation of the overall manufacturing and Inspection principles with an examination of the main advantages obtained. From this presentation of the present status, the tendencies and trends which will guide the future developments are brought out.