Quote:
Originally Posted by tgrayson  - Draw an airfoil with the leading edge to the left
- Draw the relative wind coming horizontally from the left.
- Draw a lift vector perpendicular to the relative wind.
That's life without wing tip vortices.
Now, - Modify the relative wind so that it comes from slightly above the first one you drew and angle it downwards.
- Draw a lift vector perpendicular to *this* relative wind.
Notice that the new lift vector is pointed slightly backwards. That's the origin of induced drag.
The modification you made to where the relative wind was coming from is due to the wingtip vortices; they tend to make the air around the wing move downward. |
Exactly. That is all the "floating" part of ground effect is. The ground interferes with the vorticies, reducing them if not removing them completely. This causes that lift vector to move more vertical, while reducing induced drag it is also making the lift the wing is making more effective since more of it is being applied directly into lifting the airplane. This gives you the floating effect. You're not riding on a cushion of air like you might think rather the lift the wing is making is being more effective.
Sorry if I repeated what's already been said, I didn't read the longer posts.