2235. Preliminary Design of an Advanced Technology Composite Wing for a Transport Aircraft

Paper

Abstract

The McDonnell Douglas Corporation, under contract NAS1-1-18862 to NASA Langley Research Center (LaRC), is developing the technology to allow the incorporation of an all composite wing on a commercial transport aircraft. This program, ”Innovative Composite Aircraft Primary Structure” (ICAPS), seeks to combine the performance gains available from composite primary structure with a breakthrough cost reduction made possible by the incorporation of a new manufacturing approach involving the use of dry stitched preforms and resin film infusion (RFI). The rationale for using composite rather than metallic materials for the structural wing box, together with the implications of setting weight and cost targets, is discussed with respect to total aircraft performance and risk. The discussion centers on the cover panels since these account for approximately 75 percent of the total box weight and are where the new manufacturing process finds its principal application. The required cover panel stress levels to meet specific weight savings over comparable aluminum parts are established. A discussion is presented on the influence of damage tolerance rules and repair philosophy. Stitching provides significant benefits in the design of the cover panels but also results in constraints that have to be understood by the designer. These constraints affect the selection of the material and of the material form used. Stitching parameter studies have enabled a number of basic variables to be selected for this development effort, but the designer still has to decide the degree of stitching that is required in each part. The design itself is influencing the development of a new stitching machine, and the operational aspects of the machine in turn feed back into, and constrain, the design of the structural part.