Daniel wrote:
CV, a group of test pilot trainees at Edwards AFB did an exhaustive
test on ground effect versus distance as a project during their
course; it was reported in the Feb 1990 SOARING magazine. IIRC, they
found that one had to fly a very precise profile - 0.95g push followed
by 1.05g pull, to a precise height - to see any measurable effect, and
concluded that it was better for the casual flier to fly best
lift/drag speed instead... I think they used a G103. The notation

I see. So if the results as reported here apply to calm conditions
it would mean the ground-effect technique wins out whenever there
is any significant wind gradient.

Where there is wind there is usually a wind gradient, certainly
in strong winds, meaning the ground-effect technique would normally
win against a headwind.

As I said before I totally agree about the security issues. If
you end up in a position where you need this something is already
badly wrong. And if you have the option it would be better to
pick a field you are certain you can reach rather than rely on
these effects.

CV