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This report describes an investiqation into the problem (,f the "exact" calculation of three-dimensional lifting potential flows. The designation "exact" is used to denote a method that makes no approximations in its basic formulation, such as small-perturbation or lifting-surface theories do. Obviously, numerical realities require some approximate techniques in the computer, but "exact" metheds can be numerically refined in principle to give any degree of accuracy. The first part of the study is a look at the problem of three-dimensional lifting potential flow from a fundamental standpoint, something almost totally lacking in the literature. Unlike nonlifting flow whose "physics" and mathematical description seem basically related, the mathematical description of the lifting problem is merely a model to describe by means of an inviscid flow a phenomenon that is ultimately due to viscosity. This is true even in two dimensions, but in three dimensions it leads to certain logical difficulties. The method of this report and all current "exact" mpthnds of calculating lifting flows are based on the author's previous work on three-dimensional nonlifting flows. This report describes the present method in general and in detail, including all formulas and logic. Alternatives are discussed, some Of which are discarded, while others are incorporated into the program. The present method differs from other current methods mainly in its use of finitestrength surface vorticity distributions instead of concentrated line vorticity interior to the body and in its application of the Kutta condition. Comparisons indicate advantages for the formulation of the present method. A variety of cases calculated by the present method are presented to illustrate its versatility and usefulness. Comparisons of the calculations with experimental data are presented. The importance of viscosity in the experimental results is illustrated.

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