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Old May 9th 04, 01:44 AM
Jay
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Default Lower Drag: Rounded or Sharp?

I've been wondering which shape is lower drag, a rounded one or a
sharp one. I can understand why the leading edge of a wing would be
rounded, this allows a larger range of AOA before flow speration and
stall, but what about the vertical stabilizer? Wouldn't this be
better with a sharp leading edge?

When the air hits a blunt leading edge it has to accelerate quickly to
get out of the way. At the very front, the molecules are actually
moving in a direction normal to the direction of travel of the wing.
This has got to cause drag. If the edge were sharp and the air didn't
have to react as quickly to displace, this would seem to cause less
drag.

I know that the tear drop shape is the lowest energy state, but it may
not be the lowest drag shape. I'm thinking that an eye shape may be
better for many profiles.

So I see tear drop shape profiles all over on struts, whell pants,
vertical stabilizer, etc. Looking for explanations other than "Thats
what everybody does, so they couldn't be wrong."

Regards