On an airplane wing the increase in downwash angle is partly what gives you more lift. Airplanes fly using Newtons Law of opposite and equal actions, etc. Slats, slots and flaps direct more air downward at a more vertical angle. Thus the vertical force componenet is increased. So the combination of downwash angle and amount of air forced downward is what lifts an airplane off the ground. These same principles work on sails.
Sorry for digressing a little.
On the topic of lift, I have the following link for those wanting to learn more -
http://www.grc.nasa.gov/WWW/Wright/airplane/lift1.htmlI'm certainly no expert in the field but I did fly VFR and learned to glide when I lived in Melbourne. The exact reasons as to how lift is generated are not known. However, the majority of lift is believed to be from the negative pressure on the upper surface of the wing as determined by factors like camber, chord length, angle of attack, etc, etc. The negative pressure on the upper surface of the wing "sucks" the wing (and the plane) upwards. This is how/why a plane lifts off the ground. The effect of compressed air under the wing and it's effects on lift/how a plane flies is less clearly understood.
Re: sailing, the "upper" surface of the airplane wing is, of course, the leeward side of your sail. This is why we must always keep the ticklers flying well on this side - maintain proper airflow needed to lower the pressure on the leeward side and thus generate lift. Withoutt the lift generated (ie turbulent flow on the leeward side = no lift = stalled wing), we're simply being pushed by the wind.
Now that's enough into a field that's too complicated for me to addresss further. Perhaps those of you better suited to explain this can give us all a quick refesher or correct the flagrant errors I've just stated.
Cheers
Ron
