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Thomas Stewart
 
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Default how a sail works, who can help me explain?

Some questions on Lift as applied to sail?

If Bernoulli is wrong and Newton's Law of ACTION & REACTION is what
creates Lift, why then , when a sail is at maximum lift do the tell-tale
at the leech of the sail stream back off the sail, as describe by
Bernouli and not fly at a 90 degree angle as described by Newton's
downdraft and updraft?

If Newton's Law of Action & Reaction is correct (I'm not saying it is
wrong) then the action has to be on the convex side of the sail (
Action- downdraft) to create the reaction on the concave side (Reaction-
Updraft or Lift) Why then do we look for the tell-tales to be streaming
backwards when sailing. Seems to me they should be forced straight into
the sail in various direction

Also, If Newton's Law is correct that should make the convex side of the
sail the windward side and the concave side the Lee side (
Action_Reaction) How can this be if the boat is traveling in the
direction of the convex side ( The Newtonian windward side)

If, as Pim, logic of a flat sail is the desired shape for upwind
performance, then why wouldn't a flat piece of plywood work best when
tacking up wind? ( Just maybe, Bernoulli isn't wrong for how a sail
works?)

These are some question in my mind. Maybe some of you Flight Wizards
have answer for me before I completely abandon " Bernoulli"

Ole Thom