NACA-TR-1091

Abstract

<em>A low-speed wind-tunnel investigation was made to determine the lateral control characteristics of a series of untapered low-aspect-ratio wings. Sealed flap ailerons of various spans and spanwise locations were investigated on unswept wings of aspect ratios 1.13. 2.13, 4.13, and 6.13; and various projections of 0.60-semispan retractable ailerons were investigated on the unswept wings of aspect rations 1.13, 2.13, and 4.13 and on a 45⁰ sweptback wing. The retractable ailerons investigated on the unswept wings spanned the outboard stations of each wing; whereas the plain and stepped retractable ailerons investigated on the sweptback wing were located at various spanwise stations.</em> <br><em>The variation of experimental flap aileron effectiveness with wing aspect ratio was not accurately predicted for all spans of flap ailerons by any one of the three theoretical methods with which a comparison was made. Flap aileron effectiveness increased as aileron span or wing aspect ratio was increased. The rolling effectiveness of 0.50-semipan outboard flap ailerons decreased with increasing aspect ratio, except for the low lift-coefficient range, where the aspect-ratio-2.13 wing gave somewhat higher values of rolling effectiveness than the aspect-ratio-1.13 wing produced.</em> <br><em>At equal aileron projections, the rolling effectiveness of the retractable ailerons increased with increase in aspect ratio of the unswept wings and decreased with using sweepback; however, the rolling velocities of the wings tested are estimated to be approximately equal for a given wing area at the maximum aileron projection investigated.</em> <br><em>The aileron effectiveness of plain retractable ailerons on the sweptback using generally increased when spanwise location of the aileron was moved inboard; whereas, the effectiveness of stepped retractable ailerons on the same wing generally increased at low and moderated angels of attack when this spanwise location was moved outboard.</em> <br><em>Design charts based on experimental results are presented for extimating the flap aileron effectiveness for low-aspect-ration, untapered, unswept wings.</em>