High amplitude dynamic stability characteristics of blunt 10-degree cones

An extensive investigation of the dynamic-stability characteristics of a family of spherically blunted 10" cones has been conducted in the Jet Propulsion Laboratory ( JPL ) supersonic and hypersonic windtunnels.Two testing techniques were employed ( 1 ) the free-flight technique ( 2) the captive free-oscillation technique.Parameters considered include center-of-rotation, oscillation-amplitude, Machnumber, and Reynolds-number.There were several major trends observed in the test results.For the very blunt shapes, dynamic stability was insensitive to changes in both oscillation amplitude and Mach number; however for a sharp cone, a large change was evident for variations in both Mach number and amplitude.As the Mach number increased from low to high supersonic, the dynamic stability decreased.As the Mach number continued to increase into the hypersonic regime, this trend reversed itself and the sharp cone became more stable.Variations in Reynolds number have a significant effect on dynamicstability coefficients.The magnitude of this effect decreases with increasing model nose bluntness, oscillation amplitude, and Mach number.At the higher Mach numbers, correlation between results obtained with the alternate testing techniques is excellent.But, at the lower Mach numbers ( M = 2 ) the agreement is less satisfactory, mainly because of scatter and poor quality of the captive data.