NACA-RM-L50F20

Abstract

<strong>INTRODUCTION</strong> <br>In order to increase the range of highly sweptback-wing aircraft, it becomes desirable to use wings of large aspect ratio. Reference 1 points out, however, that highly swept wings of large aspect ratio have inherently poor longitudinal stability characteristics and, therefore, the problem of in stability in the high angle-of-attack range must be considered. However, the possibility of eliminating the longitudinal instability of sweptback wings by means of leading-edge devices has been shown by previous investigations, such as references 2 and 3. Furthermore, the low effectiveness of ordinary split trailing - edge flaps on highly swept wings indicates the desirability of investigating other types of flaps. <br>With these considerations in mind, an investigation was conducted in the Langley 19-foot pressure tunnel to determine the effectiveness of leading-edge devices and double slotted trailing-edge flaps on two wings of 47.7&#176; of sweepback and aspect ratios of 5.1 and 6.0 with NACA 64-210 airfoil sections normal to the 0.286-chord line. Most of the data were obtained at a Reynolds number of approximately 6.0 x 10 ⁶ (Mach number of 0.14). The longitudinal characteristics of the plain wings have been previously reported in reference 4. The results of a similar investigation on a 47.5&#176; sweptback wing of aspect ratio 3.4 are reported in reference 5.