NACA-TN-1284

Abstract

INTRODUCTION <br>The problem of producing airplanes capable of flight speeds equal to and greater that the speed of sound with a reasonable expenditure of power has been studied by airplane designers for some time. In order to solve these problems it is necessary to design an airplane that does not exhibit a sharp drag rise near the speed of airplane that does not exhibit a sharp drag rise near the speed of sound. Reference 1 proposes the use of highly swept wings as one method of eliminating this sharp drag rise. The analysis of reference 1 is based on the assumption that only the components of the free- steam flow normal to the wing leading edge affects the pressure distribution over the wing, and thus the critical flight Mach number will be increased by the ratio of one over the cosine of the angle of weep. This analysis also indicates that the flow affecting the forces and moments of the wing is subsonic so long as the wing remains inside the Mach cone. Much information on the stability and control of a swept wing to be used at high speeds can therefore be obtained at relatively low speeds. <br>Much work has been done on wings having angles of sweepback up to 45⁰ but information on wings having sweepback greater than 45⁰ is meager. In order to obtain a bettor understanding of the problems involved with angles of sweep greater than 45⁰, tests of an exploratory nature were performed on a 60⁰ swept-back, tapered, low-drag wing. One of the problems was to improve the longitudinal stability characteristics indicated in reference 2 for a 60⁰ swept-back wing. Wing-plan-form variations, leading-edge slats (both full and partial span), and a partial-span leading-edge flap were investigated in an attempt to improve the longitudinal characteristics of the wing. Tests of several trailing-edge flaps were made to supplement the results of reference 2.