NACA-RM-L52E06

Abstract

INTRODUCTION <br>One limitation of flight-testing techniques is that, in general, an aircraft component can be tested only as part of a combination which is aerodynamically and structurally capable of stable flight. Because of interference, it is necessary in some investigations to vary the parameters of several components in order to evaluate the effects of one. In other investigations, interference effects are small or can be made so by proper design of the test vehicles. In a few cases, it is feasible to fly isolated components. The results presented herein were obtained by that method. <br>In the present investigation three wingless, finless bodies were flight tested at the Langley Pilotless Aircraft Research Station at Wallops Island, Va. The fuselage chosen for these tests was an ogive-cylinder of fineness ratio 11 which has previously been used in free-flight investigations of base pressure, wing drag, and damping in roll 0refs. 1 to 4, for examples). The models were boosted to supersonic speeds by external rockets, them allowed to coast freely. Stable flight was made possible by a special construction which placed the center of gravity less than two body diameters aft of the nose tip. Drag and base pressure were measured for the isolated fuselages, and these values were then compared with previous data to obtain the drag of a fin configuration and its effect on base pressures. One of the models had a simulated wind-tunnel support sting, and its effects on base pressure were determined. The tests covered a range of Mach numbers from 0.7 to 1.3 and Reynolds numbers from 15 x 10⁶ to 45 x 10⁶.