It's called angle of attack. Increase angle of attach to too
great a degree and the telltales will start telling their tales
in in more of a radiating manner.


"Oz1" wrote in message ...
On Mon, 7 Jul 2003 12:37:55 -0400, "Simple Simon"
wrote:

The leeward side of a sail is the side that is convex as opposed
to the windward side which is the side that is concave.

The convex side of the sail or the leeward side directs the air
over a longer path. This longer path for the air lowers the pressure
because said air must move faster to cover the increased cord.
Faster flow equals lower pressure. This low pressure combined
with the normal or slightly increased pressure on the windward
side is what creates lift.

Hmmm can you then eplain why telltales on the concave side of the sail
continue to flow?
One would have to assume that the air to cover a shorter path would be
required to travel in a straight line rather than remain attached to
the curve.


Oz1...of the 3 twins.
I welcome you to crackerbox palace,We've been expecting you.