SWEPTBACK UNTAPERED SEMISPAN WING OF ASPECT RATIO.1.59~UIPPED WITH VARIOUS 25-PERCENT-CHORD PLAIN FLAPS

A wind-tunnel investigation was made at low speed to detemine the aerodynamic characteristics of a hs ” sweptback untapered semispan wing of NACA 64.Ao1oairfoil section normal to the leading edge and aspect ratio of 1.59 equipped with 2~-percent-chordplain unsealed flaps having various spans and spanwise locations. Ltit, drag, pitching-moment, and flap hinge-moment data were obtained for the wing with the various flaps-deflectedup to 600. A comparison is ~de with data obtained on the present wing at 0 ° of sweep with an aspect ratio of 3.13. In general, changes in angle of attack, flap deflection, flap span, and spanwise location produced trends in lift, drag; pitching moment, and flap hinge moment that were similar to but of different magnitudes from those for unswept wings. Existing empirical and theoretical methods for predicting the lift effectiveness of flaps of various spans gave very good agreement with the experim@al results. Because of the increase in the drag coefficients and the associated decrease in the lift-drag ratio with increasing flap deflection, an advantage may be gsined by limiting the flaD deflection to moderate angles (about ~00),-even-further increases may be desirable, though the lift coefficients increase slightly with in flap deflection. Flap deflections greater than 30° however, when steeper glide-path angles are required