THE EFFECT OF BLUNTNESS ON THE DRAG OF SPHERICAL-TIPPED TRUNCATED CONES OF FINENESS RATIO 3 AT MACH NUMBERS 1.2 TO 7.4

The drag of spherically blunted conical models of fineness ratio 3 was investigated at Mach numbers from 1.2 to 7.4 in the Reynolds number range from 1.0 × 10 6 to 7.5 x 106. Results of the tests showed that slightly blunted models had less drag than cones of the same fineness ratio throughout the Mach number range. At Mach numbers less than 1.5, drag penalties due to large bluntnesses were moderate but these became severe with increasing Mach number. Wave drag obtained by the method of Munk and Crown, in which the wave drag is determined by integrating the momentum loss through the head shock wave, showed that the wave drag and total drag followed the same trends with increasing bluntness. Wave drag was also estimated by com-bining the experimental wave drag of a hemisphere with the theoretical wave drag of a conical afterbody, and this estimate of wave drag is believed to be adequate for many engineering purposes