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A description of the design and fabrication cost relationships of formed titanium sheet structures is given. Emphasis is placed on the potential advantages of implementing an advanced hot forming concept and related equipment. The use of this concept and/or equipment will insure quality products at minimum cost by extending current design and fabrication limitations and reducing the number of tools, parts, assembly operations, and assembly fit-up time normally required for structural assembly.

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.

This paper discusses exhaust nozzle performance, the interaction of exhaust nozzle and airframe, and the need for considering the effect of interactions when estimating overall performance. New performance parameters such as interference drag and equivalent thrust are introduced to account for these interactions. These parameters can be used to provide a consistent semi-empirical approach to optimizing exhaust nozzle/airframe performance and to measure achievements during the optimization process. Emphirical correlations based on the new parameters are displayed for several exhaust nozzle/aircraft combinations.