NACA-RM-L53F12

Abstract

INTRODUCTION <br>A knowledge of the magnitude of the effects of flap geometry and position on the span loading and pitching-moment characteristics of a wing is required in the aerodynamic and structural design of aircraft. Theoretical methods such as reference 1 are available for predicting the loading produced by a deflected flap on straight and swept wings and the semiempirical method of reference 2 is available for approximating the incremental twisting and pitching moments. Because of the lack of large-scale experimental data, the applicability of the methods of references 1 and 2 to wing with large amounts of sweep and relatively high aspect ratio, such as have been proposed for long-range, high-speed bombers, has not been ascertained. <br>A general low-speed investigation is being made in the Langley 19-foot pressure tunnel on two 45&#186; sweptback wings having aspect ratios of 8.02 and taper ratios of 0.45. One of the wings is untwisted and incorporates an NACA 631A012 airfoil section in the free-stream direction; the other employs the same thickness distribution, but contains the calculated amount of twist and camber required to produce an elliptic span load distribution and a uniform chordwise distribution at a lift coefficient of 0.7 and a Mach number of 0.9. <br>As part of this investigation tests have been made, through the linear angle-of-attack range at a Reynolds number of 4,000,000 and a Mach number of 0.19, on the wings equipped w i t h 20-percent-chord split flaps of various spans at various spanwise positions. Pressure data have been obtained in these .tests at seven spanwise stations by means of orifices alined in the free-stream direction along the wing and flap surfaces. <br>The present paper contains the results of these tests and affords a comparison in a previously unchecked aspect-ratio-sweep range of the incremental lift and pitching moment calculated by the methods of references 1 and 2 with experimental data. Results of other phases of the general investigation may be found in references 3 to 8.