"M. H. Greaves" wrote:

I think it would depend on the attitude and the angle of attack, also wing
area; the vulcan would float because of the wing area, it pushed a cushion
of air in front of it at low altitude.

I think that it's there for all a/c, look at that huge Russian
jobbie...'ekronoplanne' (or somesuch). It was designed to use
ground effect...I understand that you gotta be within about
one-half of your wingspan from the surface. You can almost
picture it, imagine why they use those 'winglets' at the tips of
Airbus and others, they prevent vortices by 'discouraging' the
higher pressure air from under the wings curling up and over the
tips to the lower pressure air above the wing.
--

-Gord.