NACA-RM-L53F24

Abstract

<strong>INTRODUCTION</strong> <br>The high-strength characteristics of wings with triangular plan forms permit the use of very thin airfoil section which provide low minimum-drag characteristics at supersonic speeds. The small values of leading-edge radius associated with thin wings, however, are known to result in poor drag-due-to lift characteristics at subsonic speeds. In order to provide quantitative information on the effects of both wing thickness and Reynolds number at subsonic speeds on the drag as well as on the lift and longitudinal stability characteristics of delta plan forms, an investigation was made in the Langley low-turbulence pressure tunnel of two delta-wing-fuselage combinations. Each configuration had a wing with leading-edge sweepback of 60&#176;, an aspect ratio of 2.31, and a taper ratio of zero. One wing had NACA 65A006 airfoil sections and the other had NACA 65A002 airfoil sections parallel to the plane of symmetry. Tests were made through a range of angle of attack from -200 to36⁰ at Reynolds numbers from 0.9 X 10⁶ to 9 X 10⁶ and at Mach numbers from 0.15 to 0.85 for the 6-percent-thick wing and 0.15 to 0.40 for the 2-percent-thick wing. Data at higher subsonic Mach numbers for the 2-percent-thick wing are available in reference 1. <br>One of the problems involved in the use of thin delta wings of constant percentage thickness is the difficulty associated with construction of the pointed tips because of the very small absolute thickness of these sections, Recent (unpublished) free-flight tests of thin delta-wing models have indicated also a tendency for the tip sections to flutter. To determine, therefore, the effects on the static aerodynamic characteristics of removal of the pointed tips, tests were also made o a third wing having the airfoil sections of the 6-percent-thick wing but with the plan form modified by removal of the outer 24.9 percent of the span. The resultant plan from was one having 60⁰ sweepback of the leading edge, an aspect ratio of 1.39, and a taper ratio of 0.249. Tests were made through a rang e of angle of attack from -40 to 36⁰ at Reynolds numbers from 3 X 10⁶ to 6 x 10⁶ and Mach number from 0.40 to 0.95