NACA-TN-730

Abstract

INTRODUCTION <br>Estimation of the stability characteristics of airplanes can be Made only if the stability derivatives of the particular airplane are known. Mathematical equations are available and convenient charts are given in reference 1 for predicting the lateral-stability characteristics of airplanes. Some of the factors affecting the values of those. derivatives arc wing, fuselage, and fin forms and the aerodynamic interference between these parts. <br>The effects on the lateral-stability characteristics that depend on yaw of several wing ferns, changes in tip shape, dihedral, taper, wing section, sweep angle, and split flaps are given in references 2 and 3. A theoretical prediction. of some of the lateral-stability characteristics for wings is given in reference 4. The purpose of the present investigation was to obtain information relative to the interference effects on lateral-stability characteristics of wing-fuselage-fin combination, Tests were made with a fuselage of circular cross section having a re-movable fin; the fuselage was tested separately and in combination with the N.A.C.A. 23012 rectangular wing, for which results of a similar investigation are given in reference 3. The wing variables were dihedral and flap deflection for each of three locations representing a low-wing, a midwing, and a high-wing monoplane. The effect of the fin was obtained for each variation of each fuselage- wing combination. <br>This paper gives the lateral-stability characteristics of the wing-fuselage-fin combinations tested and the variations with yaw in rolling-moment, yawing-moment, and side-force coefficients for the combinations.