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Some of the more significant results of an experimental investigation of the influence of edge shape on the aerodynamic characteristics of a family of low aspect ratio wings (JR > 2), having straight trailing edges and taper ratios between zero and one, are presented.The results are shown to correlate with the approximate linear lifting-surface theory of Lawrence and with the semiempirical nonlinear theory of Flax and Lawrence. The discussion centers around (1) the effects of various leading and side-edge shapes, (2) the influence of leading edges, and (3) the effects of retreating side edges. Implications of the results as regards such design factors as lift-curve slope, stability and control, and leadingedge suction and drag are discussed. In addition, the possibility of developing a new type of roll control for low aspect ratio wings, based on edge-flow-separation effects, is considered.

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When U. S. Government drawings, specifications, or other data are used for any purpose other than a definitely related Government procurement operation, the Government thereby incurs no responsibility nor any obligation whatsoever, and the fact that the Government may have tbrmulated, furnished, or in any way supplied the said drawings, specifications, or other data, is not to be regarded by implication or otherwise, or in any manner licensing the holder or any other person or corporation, or conveying any rights or permission to manufacture, use, or sell any patented invention that may in any way be related thereto. 20. ABSTRACT (Continued) experiments. The experiments were performed with airfoil models having 4% and 6% solid blockage. The initial experiments with the 6%-blockage mode] were devoted to determining a practical mode of operation when shock waves from the model extend to the wall. The most practical mode is to use wall control to obtain the desired distribution of longitudinal velocity components for subcritical walls. The Mach number is then increased and the wall control is readjusted, sequentially, until the desired test condition is achieved. At the high Mach numbers of interest, however, the available wall control was limited locally, and tunnel system changes were required. A method is reported for analyzing self-correcting wind tunnels with porous walls. The analysis ~rea~s the auxiliary compressor circuit for wall control, and it provides an approximate method for examining the trade-offs between the compression ratio of the auxiliary compressor, wall porosity, and model size. The most expeditious alternative for extending the operating range was to build and test a 4%-blockage model. The results of iteration experiments with the 4~-blockage model at M~ = 0.85, ~ = 1 o are described. They are inconclusive because of flow field fluctuations.