CoolIP index           


 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 endless applications.

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.

CoolIP                       ~Dave Santos            6 Oct 2011              AWE4412    

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 drawings ...         

Related links:


Commentary is welcome:

  • v