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Cryogenic quenching (“cryoquenching”) is a Grumman-patented process whereby the substitution of liquid nitrogen for water as the quenching medium during the heat treat cycle produces distortion-free parts. The process has been a Grumman production capability since 1963, and has increased from an annual rate of 25,000 parts to the present pace of more than 300,000 parts per year. Cryoquenching is now saving thousands of man-hours in the aerospace industry and has substantially increased the tool life of drop hammer dies, form dies, and press blocks. When fully optimized, the process will ultimately lead to an automated heat treating operation, with high quality hardware, manufactured at minimum cost, as the end product.

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.

IDEAS (Integrated Design and Analysis System) is a new approach directed toward the rapid definition of design loading conditions and internal structural element loads needed for the sizing and analysis of the primary structure of an entire aircraft. It is an integrated collection of many different kinds of computer programs and formalized calculations which are performed in particular sequence. Complete integration is of prime significance. Output data from any one kind of computer program is in the precise format required as input for subsequently used programs of the system. System capability is sufficiently broad to provide state-of-the-art analysis procedures for both variable-sweep supersonic aircraft and fixed-wing subsonic aircraft. It treats all applicable flight maneuvers, landing and catapult conditions, taxiing conditions, gust and flutter analyses.

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.

A procedure is outlined which identifies the influencing factor which must be considered when formulating a space support plan. The plan is described as the “top document” used by both management and customer to guide the support aspects of a program. A systems approach to arrive at the Support Plan is presented along with examples of analysis techniques used to perform system trade-offs.

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.