seagull
Well-Known Member
MD88, the laws of physics don't change in ground effect. The ground changes the relative flow, so the air no longer is able to be pushed up towards the wing from below as it approaches, reducing the drag without reducing the lift. Nothing magical going on there.
The other aspect is that the ground prevents the air from being pulled in from the sides, which creates a flow around the wingtip, known as vorticies. These vorticy act to reduce much of the lift (which is why high aspect ratio works, to reduce the % of the wing affected, or winglets, same idea). The ground effect is effectively like increasing the aspect ratio or adding winglets. More lift for the same wing, essentially.
The other aspect is that the ground prevents the air from being pulled in from the sides, which creates a flow around the wingtip, known as vorticies. These vorticy act to reduce much of the lift (which is why high aspect ratio works, to reduce the % of the wing affected, or winglets, same idea). The ground effect is effectively like increasing the aspect ratio or adding winglets. More lift for the same wing, essentially.