640. The Weight/Cost Interface – Determination of Minimum Program Cost

Paper

Abstract

Two alternate methods used in the selection of a preferred aerospace system are: (1) the fixed-budget approach, and (2) the fixed-effectiveness approach. In the first case, maximum effectiveness is desired for a fixed cost. The second case, wherein minimum program cost for fixed-effectiveness is the criterion for decision-making, is the subject of this presentation. A prime ingredient of this selection criterion is a knowledge of the relationship between vehicle weight and program cost. A value criterion based on parametric weight equations, weight growth factor and parametric costing techniques has been developed which provides a dollar quantity to the candidate solutions of a design problem. Changes in program cost are simply determined by knowing only the weight change and cost per pound of each design variation. From this technique, the sensitivity of program cost to changes in vehicle weight, structural materials and fabrication methods can be determined. It is no longer necessary to resize the vehicle and develop a full program cost for each design variation.