This stuff goes way beyond my pay grade and as mentioned by Pugilistic Animus, not a simple mathematical formulation that goes into some weighty theory reserved for much more gifted minds than mine.
Different types of models have been applied with different random variables, theoretical, nonlinear regression and empirical.
In most cases it is a conservative estimate in aircraft design based on corrective factors in relation to optimal taper ratio for a given sweep angle. Which can give a theoretical Oswald factor. Then correction factors are applied for span loading, fuselage,compressibility, mach number and lift to drag characteristics. Basically for everything for non planar configuration.
In other words, based on whose model you apply and without specific wing/fuselage design information. I am able to only give a conservative estimate based on a speed just short of super sonic of somewhere between 0.6 and .8 You would need more data and a specific computer design program to generate better conclusions.
Try and contact Boeing or Airbus design engineering departments for more information.
Last edited by jimmyg; 26th Nov 2013 at 12:21.