760. Initial Gross Weight and Size Estimation, Emphasizing Fighter Aircraft

Paper

Abstract

The sophisticated aspects of today’s and tomorrow’s aircraft configuration design, such as parametric studies, design synthesis, and computer generated screen displayed design, make it possible to optimize configurations for cost-effectiveness in terms of weight and size. One thing, however, is not yet possible: to digitally select a sound base-point configuration from which to perturbate in the pursuit of the foregoing objectives This still requires our human ingenuity. Gross weight can be established fairly easily by empirical weight-ratio relationships. However, explicit relationships for gross weight and size do not exist, and the entire problem spills over immediately into parametric design analysis, synthesis, etc. (References 1, 2, and 3),
It is the purpose of this paper to present some typical, fast working, and sufficiently accurate predesign methods with which to establish an initial or ‘base’ configuration, deviating not more than say +, 15% from optimum. Fighter aircraft were chosen in this paper to illustrate the methodology, which is not new in essence, although not always widely known or properly used. This paper, however, presents it in an updated and readily adaptable form for designers and military experts alike.
For any other airplane category, for propeller aircraft, or for performance requirements and drag data other than those assumed in this paper a similar set of graphs can readily be prepared, to suit the individual user’s set of circumstances. References 4 and 5 are related to this subject, but were not used in connection with
this paper