Supersonic/hypersonic Lift To Drag Ratios
At very high speeds, lift to drag ratios tend to be lower. Concorde had a lift/drag ratio of around 7 at Mach 2, whereas a 747 is around 17 at about mach 0.85.
Dietrich Küchemann developed an empirical relationship for predicting L/D ratio for high Mach:
where M is the Mach number. Windtunnel tests have shown this to be roughly accurate.
Read more about this topic: Lift-to-drag Ratio
Famous quotes containing the words lift, drag and/or ratios:
“The axioms of physics translate the laws of ethics. Thus, the whole is greater than its part; reaction is equal to action; the smallest weight may be made to lift the greatest, the difference of weight being compensated by time; and many the like propositions, which have an ethical as well as physical sense. These propositions have a much more extensive and universal sense when applied to human life, than when confined to technical use.”
—Ralph Waldo Emerson (18031882)
“Keeping up with the Joneses was a full-time job with my mother and father. It was not until many years later when I lived alone that I realized how much cheaper it was to drag the Joneses down to my level.”
—Quentin Crisp (b. 1908)
“Typography is not only a technology but is in itself a natural resource or staple, like cotton or timber or radio; and, like any staple, it shapes not only private sense ratios but also patterns of communal interdependence.”
—Marshall McLuhan (19111980)