1008. The C-5 Weight Control Program and Its Influence on Structural Efficiency

Paper

Abstract

The objective of this paper is to present an insight into the extensiveness of effort expended to control weight on the C-5 program and the resulting influence of this weight control effort on airplane structural efficiency.
The paper discusses the circumstances which created the need for a stringent C-5 weight control program; specifically, the existence of contractual weight and performance guarantees, the incorporation of pre-contractual configuration changes required for performance improvement, and the incorporation of post contractual configuration changes required to meet performance guarantees. A discussion of the above and beyond type efforts of the weight control program is given. Examples are given of the expenditures made to control weight and some of the difficulties encountered. Highlights of the C-5 design program are presented with emphasis on analysis and design practices which influenced structural efficiency. Major design changes made to save weight which had an influence on structural efficiency are reviewed. The following weight data are presented which may be used by the reader in assessing and evaluating airplane structural efficiency: (a) the final C-5 weight position relative to guarantees, (b) final structural weights compared to preliminary design estimated structural weights, and (c) the C-5 wing weight compared to other aircraft wing weights. A discussion of full scale static and fatigue test results is also presented from which the reader may make an assessment.