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Power Kite "Wind Window" and Kite Arch Catenoid Equated
More tying-together of "obvious" AWES principles-
Instruction in Power Kiting begins with an explanation of the Wind Window.
Given line stretch and sag, the Power Kite Wind Window is never exactly
spherical in curvature, but approximates a geometric catenoid section. The
inherently highly catenary Kite Arch spans its Wind Window in an ideal
position to either host sweeping suspended WECS in the Window Power Zone,
or itself sweep the Window catenoid vertically, potentially harvesting
almost the entire Window.
Filling the Window with half-domed membrane set along the catenoid gives
maximal static tug for minimal material. We keep in mind that AWES
extractable power is a sum of both lift and drag forces, that "High L/D"
is mostly a newbie fetish, and that a fully loaded AWES operates at around
L/D of around 1 or 2. For basic geometric and other practical reasons,
including control issues and tether drag, no hot sweeping wing operating
from a single anchor can ever quite match domed membrane coverage, but
sweeping is clearly potent in the Power-Zone.
These simple facts taken together suggest that a variable hybrid mix of
sweep and static lift offers the optimal coverage of the Wind Window in
varied wind conditions. A partial logical proof is that while all AWES
must have some relative motion to operate, even hot kiteplanes resort to a
parked flight mode* in their upper range of operating windspeed.
* Park aloft with FEGs or park in a constant flight-attitude during
reel-out.
Sample depictions of the Power Kite Window-
The Power Kiting: Understanding the Wind Window | Kiteboarding ...
CoolIP*
~Dave Santos 6April2012
AWES5977
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