Richard T. Whitcomb
The methods used to estimate and reduce the stresses in a swept propeller to be tested in the Langley 8-foot high-speed tunnel are presented. The incremental moments and forces produced by the centrifugal and air forces of each of the elements of the blade outboard of a given minimum section at the neutral point of that section have been added to obtain the total moments and forces at that point. The stresses at the section have then been determined using the usual beam formulas. At the points where the sweep changes abruptly, the formulas have been revised to account for the curvature of the line through neutral points of the nonuniform minimum sections at these locations. The moments about major axes of the minimum sections have been eliminated by means of the proper orientation of the blade elements.
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