Supersonic Wing Drag Calculation


A program for computation of these drag components is provided here. It may be used to compute the various components of supersonic drag for a wing of given area, length, span, and t/c at a specified Mach number and CL. The program uses the formulas for drag of an equivalent ellipse as described on the previous pages of this chapter.

Inputs
Mach Number:
CL:
AR:
ARlength:
t/c:
Results
CDw (lift):
CDw (volume):
CDi:
eeffective:


The computations are based on the following code:
with the definitions:
 beta = sqrt(mach*mach-1.0)


and:

x = pi*arl/4



The wave drag due to lift is:

 cdwl = cl*cl*x/4*(sqrt(1+beta^2/x^2)-1) 



The wave drag due to volume is:

cdwv = 4*tc^2*(beta^2+2*x^2)/(beta^2+x^2)^1.5



The vortex drag takes the usual form:

cdi = cl^2/(pi*ar)



The effective span efficiency is defined here as the drag of a low-speed ellipse (with the same span and lift) to the total lift-dependent drag of this wing

 e_effective = cdi/(cdi+cdwl)