quote:
Originally posted by blacklotusninja
Im assuming you have some knowledge of how a wing works i.e air moves faster over top due to curved shape causing a low pressure area above the wing.
Careful... that's a very common misconception which actually has nothing to do with how a wing works. If that explanation were true, then:
a) Aeroplanes couldn't fly upside down, and
b) You could get more lift by making a wing with two humps.
Both statements are false.
Here's a good site explaining how a wing
actually works:
www.amasci.com/wing/airfoil.html Basically you can take the profile of a wing, figure out the curved center line of this shape, then pretend that you have a zero thickness plate of this shape. Now run this through the air, this plate deflects the air downwards, and it's this downwash that causes lift (old Newton was right about that every action has an equal and opposite reaction blah blah)
Now to apply this to kitesurfing, you basically have a big wing on the end of a string. As you move this through the window, the angle of attack of this wing relative to the wind changes... I could show you graphs of airfoils for various angles of attack but they're hard to read and boring. In simple terms, the bigger the angle of the wing to the airflow, and the higher the airspeed, the more it deflects the wind and therefore the more lift it creates. (Until it stalls, which is a whole different kettle of fish!!)
When it's in the middle of the window, this is where it deflects the air the most, so it's also the area where you feel the most pull.
Hope this helps, physics is a lot of fun, too few people really understand it. Including the guy in my local windsurfing shop who tried to tell me that the energy of my windsurfing sail gets converted into heat when my arms are bent, but not when my arms are straight... wtf?
bestest regards you're friend stoojio
