Hypersonic viscous drag effects on blunt slender cones

Experimental drag data from a series of cone models are presented over a wide range of Reynolds numbers at hypersonic flow conditions. The data include Mach numbers from 9 to 22 with Reynolds numbers based on model length ranging from 600 to 500,000. Most data were obtained with test model surface temperature cold relative to the stagnation temperature; a limited amount of hot-wall data were obtained. The influence of viscous drag on the lift-drag ratio of slender blunt cones is shown experimentally and theoretically. Drag reduction by boundary-layer gas injection is shown experimentally for both coldand hot-wall test conditions. Theoretical estimates based on existing theories are given, and the significant contributions to the zero-lift, viscous drag rise of cold-wall cones are identified as the usual similar or Blasius friction drag and transverse curvature effects. The theoretical estimates are shown to offer a good engineering approximation to the hypersonic viscous drag of coldwall, blunt slender cones within the con tint; um flow regime.