Summary

This Toolbox calculates the overall pressure drag of an axisymmetric body, which is the sum of the jet-off base drag coefficient and, if present, the boat-tail pressure-drag coefficient of a conical boat-tail. The program follows the methods of ESDU 76033 and ESDU 77020 with the graphical data held in digital form. The sketch below shows the geometric parameters defining an axisymmetric body with a boat-tail.

ESDU 76033:

Provides a method for estimating the jet-off base drag coefficient of cylindrical bodies with conical boat-tailing, at Mach numbers up to 0.8 and with turbulent boundary layers over the body. The method is purely empirical, based on data mostly obtained from wind-tunnel investigations and a few tests conducted on free-flight models with cylindrical bases.

ESDU 77020:

Provides a means of estimating the boat-tail pressure-drag coefficient, at Mach numbers up to 0.8, of conical boat-tails. The method is purely empirical, based on data mostly obtained from wind-tunnel investigations.

Note:

The user should consult ESDU 76033 and ESDU 77020 for full specification and discussion of the configurations and flow conditions covered by the data used in the derivation of the methods, and additional advice on the applicability.