NACA-TN-4042

Abstract

An investigation has been conducted horizontal-tail location and size on the to determine the effects of longitudinal aerodynamic characteristics of an airplane model having a triangular wing. The wing had an aspect ratio of 3 and the NACA 0003.5-63 section in the stresmwise direction. Two horizontal tails were tested which had areas of either 16.7 or 21.9 percent of the wing area. Each of the horizontal tails had an aspect ratio of 4, a taper ratio of 0.33, the NACA 0004-64 section, and no sweepback of the 50-percent-chord line. Tests were conducted with the horizontal tails located -0.10, 0, 0.10, and 0.20 wing semispans above the chord plane of the wing at longitudinal distances of 1.2 and 1.5 mean aerodynamic chord lengths behind the moment center. The wind tunnel tests were conducted at a Reynolds number of 2.5 million at Mach numbers from 0.25 to 0.95. <br>The directional stability diminished markedly&#160; at high angles of attack. The directional stability for a given tail volume was greater for the mid-wing than for the high-wing configuration because of more favorable wing-tail interference. It was found that the contribution of the vertical tail to the directional stability-of the fuselage-tail combination at zero angle of attack could be estimated from existing methods. The variation of rudder effectiveness with either angle of attack or sideslip was small. The ailerons were found to provide adequate lateral control. Differential deflection of the two halves of the horizontal tail to provide lateral control was found to be relatively ineffective.