Quoting Blackbird (Thread starter):
*I'm wondering what the maximum theoretical L/D ratio and the maximum practical L/D ratio achievable by an airfoil or airplane/airfoil combination at the following Mach numbers?* |

Max theoretical would just be the L/D of the

2D airfoil at the speed of interest. But you can never achieve that in reality.

Max practical is a very strong function of aspect ratio (for subsonic). Off the top of my head, I'm not sure what happens at supersonic but the aspect ratio affect must taper off because the wingtips can only communicate with a small portion of the flow.

Quoting Blackbird (Thread starter):
*Also does the Breguet-Range equation actually equate to a plane having an actually higher L/D ratio as a result of mach number increased? * |

Sort of. The B-R equation just looks at what the L/D actually is...it doesn't really care how you got it. However, the integration behind the equation assumes that L/D (and propulsive efficiency and speed) are constant over the flight, and that's probably not a legitimate assumption for some high Mach flights.

Tom.