This past week @ULSF we’ve been quietly working. Josh (@PicoRover) has been working on N and X Prize propulsion questions, and I’ve been working mostly on 3D graphics, learning OpenGL, for the development of a shape in computational mesh format for aerodynamic analysis.
You may recall that my current course of study is in a space plane concept for conventional take off and landing. The shapes I’m looking into are in the flying wing neighborhood.
I was very happy a couple weeks ago to learn about the Sears-Haack body, Whitcomb’s Area Rule, a mathematical model for minimizing aerodynamic wave drag. Flight through the atmosphere encounters the medium in a wave phenomenon, not unlike a boat producing a wave from its bow. Traveling at less than the speed of sound, wave drag is not very significant. However at the speed of sound — which decreases with altitude — the barrier is the onset of critical wave drag.
Swept wings are an alternative approach to minimizing wave drag, through the oblique redistribution of pressure across the airfoil. As far as I understand it, sweeping the wing is reducing its efficiency in order to reduce its drag. From this perspective, I think Burt Rutan’s later designs take the approach of not sweeping in favor of a Sears-Haack-Whitcomb approach.