Kite-based Fixed Platform in Calm; "Perpetual"
Flight from Two Anchors*
A claimed unique advantage of AWE flygen concepts over classic kites is
the potential to launch, land, and loiter in no wind by motoring. Of
course ordinary kites are commonly towed by vehicles in calm, but this
requires a track, open field, or water. An E-Flight platform on a
conductive tether can usefully hover in place from a fixed anchor point.
If basic kites of rag and string could do the same job from fixed points,
it would tend to be a cheaper, safer, simpler system.
Last January, at the World Kite Museum Indoor Kite Festival, KiteLab
Ilwaco showed how to keep an ordinary kite aloft in calm by three lines
tugged in sequence from three fixed anchors, including controlled launch
and landing. From the same three anchors, an aerial payload platform can
be held still by a fixed string tripod, as the tug-powered kite circles
over it to hold it up. This is a neat solution to the long-standing
aviation problem of practical persistent flight and station-keeping, with
The latest prototype works with just two anchor points. A kite is towed
from a moving cable between the anchors. One end is a drive winch; the
other just a return bungee. The kite flies by its leader from the tow
cable moving to and fro. A modest dip in terrain will keep the cable off
the ground. The "passive control" trick is to trim of the kite to turn
circles driven at the line-pumping frequency. The kite will circle aloft
indefinitely and can even be consistently launched and landed by timed
pumping. A steering servo enables more flight modes. Given wind, the kite
can work cross-wind in any direction, regardless of towline direction,
back-driving the tow-winch to generate power.
A crude public demo is planned this weekend at One Sky, One World event
here (Long Beach, WA). The next goal is to master end-to-end sessions of
stable transitions between wind driven AWE generation and winch driven
flight, with repeatable take offs and landings. Zhang Lab of NYC is doing
related experimental studies of pulse driven flight. Massive AWE arrays
might someday be operated by phased tugs.
6 Oct 2011
Comment and development of this topic will be occurring here.
All, send notes, drawings, and photographs!
Terms and aspects:
- * As JoeF of KiteLab Group described years ago in group with
Commentary is welcome: