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Old Dec 17, 2012, 05:05 PM
Tim Green is online now
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Ashtabula, OH USA
Joined May 1999
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Quote:
Originally Posted by eflightray View Post
Low pressure on top, higher pressure underneath. Yet the low pressure air causes downwash into the higher pressure air ?

Still can't get my head around that.
Maybe not - but you hit the nail on the head, so to speak. Low pressure on top is caused by the fact that the wing is moving forward through the air - that creates a slight vacuum (low pressure zone) behind the wing. Which is also the top of the wing.

This helps to accelerate the air downward, as the wing moves through the air. Along with the fact that the air is a fluid, and "sticks" to the top of the wing - we get a lot of air both accelerated, and moved in a downward direction, as it falls down the back/top of the wing as the wing moves forward.

This is nothing less than Newton's third - action and reaction.

The wing's action is moving air downward as the wing passes through the previously still air - and the reaction is a force called lift.

So - it's good that your brain doesn't accept the observation you noted - it's all good. You are in sync with NASA's understanding of lift. Can't be bad.

BTW - This force added to air is measurable, with a large scale, placed under a hovering quadcopter or helicopter.
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