NACA-TN-1671

Abstract

INTRODUCTION <br>Estimation of the dynamic flight characteristics of airplanes requires a knowledge of the component forces and moments resulting from the orientation of the airplane with respect to the air stream and from the rate of angular motion of the airplane about each of its axes. The forces and moments resulting from the orientation of the airplane normally are expressed as the static stability derivatives, which are readily determined from conventional wind-tunnel tests. The forces and moments resulting from the angular motions (rotary derivatives) have generally been estimated from theory because of the lack of a convenient, experimental technique. <br>The recent application of the rolling-flow and curved-flow principle in the Langley stability tunnel has made possible the determination of both rotary and static stability derivatives with about the same ease. Preliminary tests (data obtained In the Langley stability tunnel) have indicated that although& the rotary stability derivatives of unswept wings of moderate or high aspect ratio can be predicted quite accurately from the available theory, the use of sweep and, perhaps, low aspect ratio introduces effects which are not readily amenable to theoretical treatment. For this reason, a systematic research program has been established for the purpose of determining the effects of various geometric variables on both rotary and static stability characteristics. <br>This paper presents the results of an investigation made to determine the effect of taper ratio on the static and yawing stability derivatives of three tapered wings each with a constant sweepback of 45&#176; at the quarter-chord line and with an aspect-ratio of 2.61. The experimental results are compared with theory.