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美国政府科技报告
>AN ANALYSIS OF I'HE FACTORS AFFECTING THE LOSS IN LIFT ANDnSHIFT IN AERODYNAMIC CENTER PRODUCED BY THE DISTORTIONnOF A SWEPT WING UNDER AERODYNAMIC LOAD
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AN ANALYSIS OF I'HE FACTORS AFFECTING THE LOSS IN LIFT ANDnSHIFT IN AERODYNAMIC CENTER PRODUCED BY THE DISTORTIONnOF A SWEPT WING UNDER AERODYNAMIC LOAD
A simplified analysis has been made of the factors affecting the loss in lift and the shift in aerodynamic center of a swept wing due to its distortion Tinder aerodynamic load. The manner in which these particular aeroelastic effects influence the longitudinal stability of an airplane has been considered.nThe results show that large variations in the aeroelastic effects, associated with wing bending are produced by changes in aspect ratio, sweep angle, and thickness ratio. These variations are, in general, larger than those produced in wing-bending stress and with the thick¬ness ratios being contemplated today restrict the aspect ratio to low values' for large angles of sweep and, conversely, restrict the sweep angles to low values for large aspect ratios, Expressions obtained for the ratio of angle-of-attack change due to wing torsion to .angle-of-attack change due to wing bending show that torsion effects tend to alleviate the effects of bending, but the angle-of-attack changes due to torsion are much smaller than those due to bending except for wings with low values, of sweep, aspect ratio, or, in particular, a combination of the two. Decreasing the plan-form taper ratio is another means for extending the combinations of sweep and. aspect ratio without an increase in wing structural weight. When aeroelastic considerations are important, a more rapid increase in the structural weight of wings with increase in airplane size appears to occur than for:designs based on stress alone. The choice of steel or duralumin as a structural material is not significant insofar as aeroelastic considerations are concerned.
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