NACA-RM-A9K01

Abstract

INTRODUCTION <br>The use of the swept-wing plan form for delaying the onset of serious compressibility effects to higher Mach numbers has received Considerable theoretical and experimental study. A knowledge of the degree to which these compressibility effects can be delayed and alleviated by wing sweep is of value in the proper design and application of swept wings. It is important to how the Mach number above which the rapid drag increase, the loss of lift, and the sudden changes in load distribution and longitudinal stability occur. The basic theory o f the swept wing was developed f r o m consideration of the-flaw over a yawed airfoil of infinite span and has served as a very useful guide for qualitative estimates of the benefits of wing sweep. The simple sweep theory does not however, take account of many of the variables in the flow over a swept wing of finite span. Pressure measurements at high Mach numbers correlated with measurements of forces and moments are important to the extension of present swept-wing theory and to a better understanding of the flow phenomena involved. <br>In this report, the results of such an investigation are presented for a wing having moderate sweepback. The tests were conducted in the Ames 12-foot pressure wind tunnel at Mach numbers from 0.18 to 0.94 and a constant Reynolds number of 2,000,000. In the analysis of the data, an effort has been made to correlate the changes in local Wing pressures with the resulting changes in total forces, particularly in the range of Mach numbers for which supercritical flow is developing on the wing.