Roll Damping Derivative Calculations For Spinning Sharp And Blunt Cones In Supersonic And Hypersonic Flow PDF Download

The roll damping derivatives for a 10 deg cone with various nose bluntness ratios were measured at Mach 12.7 and 14.2 Re = 250,000, in axial flow and at angles of attack up to plus or minus 8 degrees. An air bearing, supporting the model with freedom in roll, was designed specifically for these tests. The bearing performance is described in detail. The measured derivatives compare very favorably with Quinn's laminar roll damping theory for blunted cones in axial flow. A moderate decrease of the magnitude of the derivatives results from blunting the nose. At angles of attack, this blunt nose effect diminishes and the blunt cone derivatives approach the sharp cone values with increasing angle of attack. Experimental difficulties at angles of attack were traced to possible free stream deficiencies and were overcome by increasing the model roll rate. (Author).