The need for evaluating and optimizing airframes of advanced aircraft configurations with exceptional speed and accuracy has resulted in the development of highly sophisticated computerized techniques. Sensitivity of these programs to advanced materials, construction types, aeroelasticity, structural dynamics, configuration geometry, airloads, missions, and performance has all but obsoleted the statistical approach to the problem solution. The competitive nature of the field has also placed unusually severe demands on calendar time available for such evaluations. This has resulted in the development of integrated analytical computer programs that have the required sensitivity and rapid turnaround time to face the competitive nature of today's environment.
At Rockwell International's Los Angeles Aircraft Division a Structural Weight Estimation Program has been developed, both with IR&D funds and as stand-alone programs, and as a completely self-contained, integrated program which integrates all necessary disciplinary functions through data management modules that control the logic of the more than 200 subroutines. All primary structural components are synthesized through idealized approximations of the physical characteristics of the required structure. Secondary structure is estimated using both statistical and analytical procedures. The output of the program is a weight statement of the complete air vehicle, vehicle mass properties, and a description of primary structural members. Use of this program has resulted in significantly improved management and technical visibility into the sensitivity of airframes to important structural and configuration parameters leading to higher performance and lower cost products.