# Re: Ground Effect & Gliding Q

HP Cunningham wrote:It could, but why not open them
when leaping out of the tree? As anaside, it would
take an awfully big tree to hold either type of Quetz
ifthat is what Q stands for in the subject line.A) To
build up speed.  B) Q=question. Sorry about that =)
Ground effectfollows the Biot-Savart law and works
mostly to reduce induced drag withthe amount of
reduction increasing as the HAG is reduced. It does
notnecessarily increase lift, and at some ratios of
chord/HAG, lift isactually reduced. Think of ground
effect primarily as a means ofimproving the overall
lift/drag ratio by reducing drag.Thank you for the
clarification here. A website on W.I.G.E. planes was
somewhat misleading. So basically you can expect lift
to be somewhat constant while drag is reduced,
resulting in a slight upward thrust upon approach of
the ground. I was thinking along the lines of an area
of pressurized air between the wings and water
creating the additional lift - something that could be
bounced off of. Clearly, I was wrong.   I don't see
any way that the technique described could have
increasedefficiency enough to help, and it sounds
counterproductive at firstblush. Why not just
establish a glide at a low enough HAG to help
withinduced drag and then, as speed gradually bleeds
off and aoa increases,gradually lower the HAG very
slightly and gradually to keep lowering theinduced
drag as required to remain above stall speed. That
makes perfect sense if you are in it for the long
haul, but what if the evolutionary objective was to
maintain the highest possible airspeed for a maximum
given time interval?  If I understand you correctly,
wouldn't intermittent use of the wings in the low-drag
ground-effect zone result in a higher airspeed for a
greater distance relative to intermittent wing use at
an increased HAG with the same initial velocity?
Hopefully I'm not overlooking another critical
factor....   -WR

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