NACA-RM-L50H29

Abstract

INTRODUCTION <br>The sensitivity of the maximum lift coefficient t o mall changes in the position of slotted flaps with relation to the airfoil is shown in reference 1. In the past , two-dimensional tests have been used as. the basis for determining the optimum position of these flaps on unswept wings. <br>With the advent of swept wings there has been some questions to the validity of basing swept-wing flap positions on two-dimensional tests. Furthermore, considerations of the stalling characteristics of some sweptback wings indicate that the wing maximum lift coefficients. May be relatively insensitive to changes in the slotted-flap position so that the optimum flap position must then be established on a basis other than maximum lift. <br>An investigation was undertaken, therefore, to establish the relationship of the optimum flap positions on sweptback wing to those determined from two-dimensional tests and to evaluate the effects of flap position. Positioning tests of a partial-span single slotted flap on a 47.7⁰ sweptback-wing - fuselage combination were made in the Langley 19-foot pressure tunnel. The wing had an aspect ratio of 5.1, taper ratio of 0.383, and NACA 64-210 airfoil sections normal to the 0.286-chord line. Most of the tests were conducted at a Reynolds number of 4.0 x 10⁶ and a Mach number of 0.10 and the rest at a Reynolds number of 6.0 X 10⁶ and Mach number of 0.14.