Do Winglets reduce ground effect

I do not think I had "thermic help" over the hot concrete/pavement. I think the tall grass negated the ground effect.

On Friday, December 16, 2016 at 1:51:22 PM UTC-8, Charlie M. (UH & 002 owner/pilot) wrote:
I would sorta guess you had "thermic help" when over the pavement while you may have had sink over the grass.

At 22:09 16 December 2016, Jonathan St. Cloud wrote:
I do not think I had "thermic help" over the hot
concrete/pavement. I
think the tall grass negated the ground effect.

On Friday, December 16, 2016 at 1:51:22 PM UTC-8, Charlie M.
(UH & 002
owner/pilot) wrote:
I would sorta guess you had "thermic help" when over the
pavement while
you may have had sink over the grass.

I would hazard to say that rotorcraft ground effect is not the same
as fixed wing ground effect. That is a whole other ball of wax...
When they took Bin Laden out, they had practiced in a mocked up
area with chain linked fences surrounding the "compound". The
reality was 8' concrete walls which deflected the blast upwards to
create a vortex. As I recall, the temperature inside the compound
was also ~15°F hotter than forecast (or reported by agents in the
field). That pilot did a great job in a controlled crash, as the
conditions inside the compound (vortex, temps, altitude) would not
let him hover at that weight. Rotorcraft (V-22 included) downwash
and vortices are a whole other animal unto themselves. Comparing
them to glider ground effect is "apples to oranges"...

While I do live in "helicopter central" (Close to the main Sikorsky
plant), I only have a cursory understanding of that arena through
education and friends / family in that business. I would leave the
technical answer to your rotorcraft question to a rotary aircraft
specialist. Sikorsky's "Skunk Works" is in Elmira, and I assume
there are some of those employees who are also glider pilots that
can answer your helicopter related question. I know that one of our
old glider club members transferred there to work at the
"Hawkworks" when it first opened.

RO

Hovering in ground effect takes less energy over hard surfaces than over water or grass. Well known. No idea if it matters for fixed wing ground effects, my guess is not, or not significantly.