| Abstract: | The subject of this study is the effects of the curved wake on the airloads of a helicopter blade in hovering flight. In most investigations of unsteady airloads, two-dimensional strip theory is used and the wake is assumed to be rectilinear. A few authors have tried to include the effects of the curved wake on a lifting line basis, but it is believed that no one has yet attempted to solve the problem on the basis of a full lifting surface theory. By using a novel numerical technique this is accomplished in this paper, and comparisons are made between the aerodynamic coefficients calculated with and without a curved wake. It is shown that inclusion of wake curvature has an appreciable effect on the blade's lift and pitching moment coefficients. |
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