# 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)`