NACA-RM-A54H26 REV A

Abstract

INTRODUCTION <br>As a result of the current interest in the application of retractable spoiler ailerons as lateral controls on high-speed aircraft, a considerable number of tests have been made using various types of spoiler configurations. The results of some of these tests are presented in references 1 to 10, and reference 11 contains a bibliography of spoiler information. <br>The great number of wing-plan-form-spoiler combinations possible, however, creates a need for a method of predicting spoiler rolling-moment effectiveness which accounts for as many of the variables involved as possible. In reference 7 and 9 are presented the results of two attempts to predict spoiler effectiveness. Each of these methods is based on the application of a flap-effectiveness theory. The agreement of experimental and predicted results is good for unswept wings. For a swept wing, however, the method of reference 9 is inapplicable since the method was developed using the antisymmetrical span loading of unswept wings only. Reference 7 described an empirical modification to this method to account for the effects of sweep; however, a comparison of the predicted and experimental spoiler effectiveness shows the predicted values to be too high for spoilers on swept wings. <br>It is the purpose of this report to describe a method of predicting spoiler rolling-moment effectiveness based on the simplified lifting-surface flap theory of reference 12. To apply this flap theory to spoilers, it was necessary to obtain test data of spoilers on two-dimensional wings, and to employ an empirical correction when predicting the effectiveness of partial-span spoilers on swept wings. The results of applying the present method to the configurations described in references 1 to 8 (see table I and fig. 1) and the comparison with the experimental data are presented herein.