The calculation of the wave drag of a family of low-drag axisymmetric nose shapes of fineness ratio 4.5 at zero incidence at supersonic speeds

摘要

The pressure drag coefficients of a particular familyof convex logarithmic projectile nose shapes in which the noseangle is an important parameter have been calculated over a rangeof supersonic Mach numbers using a rapid approximate method dueto Zienkiewicz.5The optimum nose angle for minimum wave drag of theseprofiles for each Mach number has been obtained. It is shownthat above N = 1.5„ approximately, the optimum shape is similarto the hypersonic optimum profile and has the sane or- less wavedrag than this profile. However for values of M/F, where Pis the fineness ratio, below 0.5, both the hypersonic and thelogarithmic optimum profiles have a higher drag than the so-calledcubic profile (Ref, 9).