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Old 17th June 2011, 07:19 PM   #20
Floyd
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Join Date: Sep 2006
Posts: 459
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Ken

Agree boards blow down beach but not when you are stood on them !!!

Water is 400 times heavier than air;stands to reason any water effects on board are going to have about: well 400 times more effect !

Unreg was talking about planing; air effects on planing are minimal but fair point windage on front of board/under hull especially when unloaded could effect (does effect) the board.

Once board leaves water any wind will only want to blow board down wind (once board has lost momentum).The wind could only produce lift if there is some force opposing it.ie your fin or once in air your momentum.


Wind alone can not produce lift.Its a common misconception. A kite needs tethering; a hanglider needs rising air. (It dives at a slower rate than air (wind) is rising to gain height) Its why a hanglider needs a hill or a tow. (Hill makes wind rise;the tow opposes the wind to produce lift)
Take away the opposing force and fairly quickly you are coming down.
Not sure about wind producing lift on board whilst in air; if it does its only through board/riders own momentum ; which would produce some lift with or without the wind.Would a thrown boomerang go higher on a windy day ??????

Fin only produces lift against gravity whilst not vertical. If it were horizontal with correct AoA all its lift would be against gravity but whilst vertical no force helps planing and the lift from flex of fin would be minimal.(ie flex is only 10 degrees or so and only over last few inches.)
Fins do not help planing at all.Not directly.Towed behind a boat a fin less board would plane at same point as a finned one.Fin is there to stop leeway;this produces motion which produces planing.
But when railing quite a bit of fin lift helps planing but the board as a planing surface is less efficient when angled ???

Windsurfing is a mixture of aerodynamics;hydrodynamics;the itereaction between the two and lots of BS for good measure.!!!!!!!!

Last edited by Floyd; 17th June 2011 at 07:52 PM.
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