NACA-TN-1517

Abstract

INTRODUCTION <br>An extensive investigation of control-surface characteristics is being conducted by the Langley Laboratory of the National Advisory Committee for Aeronautics that includes several types of flaps of various chords. <br>Among the control surfaces included in the investigation is a 25-percent airfoil-chord control flap with a trimming and balancing flap having a chord twice the control-flap chord, or a 50 percent airfoil chord, that is linked to give hinge-moment balance with angle of attack and flap deflection (reference 1). In order to calculate the characteristics for this arrangement, it was necessary to obtain the rate of change of control-flap hinge-moment coefficient with trim-flap deflection and the rate of change of trim-flap hing-moment coefficient with control flap deflection-as well as the lift effectiveness, the rate of change of hinge-moment coefficient with angle of attack for both the control flap and the trim flap independently. These parameters were all estimated form pressure-distribution data of reference 2 since no data were available for 25-percent-airfoil-chord and 50-percent-airfoil-chord flaps. <br>The purpose of the present investigation is to determine the aerodynamic characteristics of 25-percent-airfoil-chord and 50-percent-airfoil-chord plain flaps independently and in combination and thus to provide a check on the parameters calculated form reference 2.