J. Richard Spahr
A wind tunnel investigation was conducted at a Mach number of 1.96 and at Reynolds numbers (based on the mean aerodynamic chord of the exposed wing) of 0.36 and 1.03 million to determine the normal forces, pitching moments, and rolling moments contributed by each wing panel of a cruciform-wing and body combination over a wide range of combined angles of pitch and roll. The wings were triangular of aspect ratio 2, and the body was an ogive-cylinder combination. The effects of forebody length and roughness and of the presence of the adjacent panels on these panel contributions were determined. The results of the investigation show that large changes in the panel forces and moments can occur as the result of combined angles. A general theoretical method based on slender-body and strip theories was found to yield results in good agreement with the wind-tunnel measurements. These comparisons indicate that the changes in the panel characteristics due to combined angles are caused primarily by a cross coupling between the sidewash velocities due to angle of attack and sideslip and by the presence of forebody vortices due to crossflow separation. It was found that an increase in forebody length increases the effect of the forebody vortices because of the dependence of the strength of these vortices on the forebody length.
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