SOME EXPERIMENTAL EFFECTS OF AFTERBODY SHAPE ON THE ZERO-LIFT DRAG OF BODIES FOR MACH NUMBERS BBETWEEN 0.8 AND 1.3

Zero-lift drag data were obtained on a series of fin-stabilized bodies differing only in afterbody shape. Three series of afterbodies (fineness ratios 1.78, 3.00, and 5) with varying ratios of base radius to maximum radius (0, 0.458, 0.700, and 1) were combined with a fineness-ratio-7.13 parabolic nose. Both conical and parabolic afterbodies were tested. The models were launched from the Langley helium gun, and data were obtained for Mach numbers from 0.8 to 1.3 and for Reynolds numbers (based on body length) of about 10 x 10 to the 6th power. The results indicate that a conical angle of about 4.5 deg will give the minimum drag for any fineness ratio less than 6, and that the minimum-drag is approximately 30 to 40 percent of that for a square-base body of fineness ratio 0.