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post #24 of Old 06-19-2015
RichH
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Re: Sailing with excess brain power

Quote:
Originally Posted by MITBeta View Post
Lift does not require a curved surface, nor even a difference in distance over the two sides of the foil. If it did, planes would not be able to fly upside-down.

"A flat plate can generate lift, but not as much as a streamlined airfoil, and with somewhat higher drag." ... as long as there is an angle of attack.

https://en.wikipedia.org/?title=Lift_(force)
Very Good analogy but only part one of 2 parts.
Part 1: Bernoulli Effect of the lee-side of the plate, sail, foil, etc.
Part 2: Newtons 3rd Law - action versus equal reaction (boat)

Combine 1 & 2 together and you have the 'pumpkin seed effect': ... pushing your index finger (sails - at a slightly non-aligned angle ... AOA) against a slippery pumpkin seed on top of your thumb (lateral resistance - or CLR) = 'squirt'.

;-)
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