NACA-RM-L9B02

Abstract

INTRODUCTION <br>The problem of securing adequate lateral control for high-speed aircraft employing sweptback wings requires careful consideration for both the high-speed and the low-speed flight conditions. An investigation at high subsonic and transonic speeds (M=0.50 to 1.2) of a 20-percent-chord, 50-percent-span outboard aileron on a 42.7&#186; sweptback wing showed that changing the circular-arc aileron contour to a flat sided aileron contour with finite trailing-edge thickness eliminated reversal of control in most cases and generally improved the aileron control characteristics (reference 1). In addition, an investigation at a mach number of 1.9 (reference 2) also showed some improvement in rolling effectives resulting from the use of the thick aileron. Inasmuch as the aileron with finite trailing-edge thickness produced desirable control characteristics for high-speed flight, it was of particular interest to determine the characteristics of this aileron for low-speed, high-attitude flight, conditions. Therefore, incidental to a general investigation in the Langley full-scale tunnel of a 47.5&#176; sweptback wing with symmetrical circular-arc airfoil sections, tests were made of the wing with a 20-percent-chord, 50-percent-span outboard aileron with both the circular-arc contour and the flat-sided contour with finite trailing-edge thickness. A trailing-edge thickness of one-half the aileron-hinge-line thickness was tested inasmuch as the results of reference 1 indicated that, in general, this configuration was more effective than other trailing-edge thicknesses. <br>The investigation included measurements at a Reynolds number of about 4.3 X 10⁶ and a mach number of about 0.07 of the lift, the drag, and the pitching-moment coefficients of the basic wing and of the wing with the finite-trailing-edge-thickness aileron installed for a large angle-of-attack range. The aileron effectiveness was also determined for the two aileron configurations from tests with the right aileron deflected through a range from 0&#176; to 19.6&#176;