The paper describes the development of the design and the fabrication procedures required to replace an existing aluminum section of wing structure with a part made of boron-epoxy.
The wing box extension was selected as a significant aircraft demonstration component for boron-epoxy because it incorporates many of the problems associated with aircraft structures such as access covers, control surface mountings, contoured surfaces, and fuel pressurization; and because of the variety of loads and environmental conditions involved.
Although the existing aluminum design is unpressurized, the demonstration component has been designed to include a pressurized cell in order to demonstrate the feasibility of building an integral fuel tank.
Representative test data and specimens, design allowable philosophy used, and specific weight-strength comparisons with typical aircraft materials are presented. Process techniques used in boron laminate fabrication are discussed.