NACA-RM-A6K15

Abstract

INTRODUCTION <br>Theory indicates and experiment has shown that the prime aerodynamic effete of wing sweep is to reduce by the cosine of the angle of sweep the effective flight velocity experienced the airpoil sections of the wing. This then enables increases in maximum flight speed to be attained before serious compressibility effects are encountered. Theory and experiment also show that wing sweep introduces a number of stability and control problems, the seriousness of which becomes accentuated at low flight speeds. <br>Small scale tests have pointed out the general nature of these problems and indicated those which must be overcome if the high-speed benefits of sweep are to be realized. They have also suggested that boundary-layer flow and, hence, Reynolds number has a profound influence on measured characteristics and that the value of small scale tests remain somewhat doubtful until the extent of this influence is understood. <br>Since no large scale data were available for wings with large angles of sweep, an investigation of the effects of sweep was conducted in the Ames 40- by 80-foot wind tunnel and the results are reported herein. It is believed that these data will go far towards establishing the datum required to estimate the effects of scale on highly swept wing plan forms. With this knowledge at hand it is evident that the value of future small scale tests will be considerably increased. <br>This report discusses a summary of the basic results and compares them with simple swept-wing theories and, whero possible, with existing small-scalo data (references 1,2, and 3). To make the basic data available for further analyses they are included as an appendix to this report.