Standard" AWE Solution Proven     
June 22, 2009
M165       M166       Image    DemoParts  
Demo1vid "...generating power. That's a looping kite under a lifter kite."  

Recently JoeF proposed a standard AWE design be developed that anyone anywhere could cobble together. It had to be safe, simple, cheap, & effective.

Today at sunset over the NW Pacific a tripod tether was robustly driven by a cheap X-Kite DC 60 sport kite lifted by a Premier 14 Morse sled. Strong rotary power at the ground centerpoint of the tripod was produced. The simple kit was completed by some strings, 3 Gomberg mini fabric sand anchors to define the tripod feet, 3 Ronstan pulleys as corner blocks, & two heavy fishing swivels. Its all COTS*, about 100 bucks worth for around 30 watts of power in the ~12 knot breeze, with a potential of maybe 100 watts peak in more wind.

This concept is Passive Control AWE, no fancy avionics required.
The generator or other workcell stays on the ground, minimal mass aloft, high safety factor, low capital risk.
Capital Cost Intensity could hardly be lower, except for DIY from salvage & scrap.
Quality swivels & pulleys are desirable, but much cheaper than the massive turrets & levers, large tracks & such of other AWE schemes.
The looping wing stops spinning in a dying breeze before landing & the Morse sled self-relaunches after calm. Tangle/snag potential is quite low.
The tripod-tether accepts input from any direction. Various tuning inputs can enhance performance, but the system is so robust such frills are unnecessary.
The legs of the tripod drive an orbiting centerpoint in by three-phase rotation, perfect for turning a crank, but also will direct-drive a reciprocating load.
The initial load was a small log that promptly plowed a deep oval rut into the sand. Various test loads are next. A De Prony brake is being made from a geared crank driven grinder to measure absolute shaft-power. Geared generators will be simple crank driven by the string input, but a triple sprag or triple crank shaft may be favored in some set-ups.
The looping wing's mass acts like a flywheel input to the tripod-tether, elegant torque transmission by mere string.
Hot tethered foils far exceed the L/D performance of the cheap DC-60 sport kite. A Rev Super Blast under an HQ 9.0 XXL Power Sled would be a sweet kilowatt scale COTS system. The core concept is mainly scale limited by the lifter. A 5000 sq ft KiteShip OL kite can be stabilized for the role for a megawatt scale implementation. Massed arrays of these units could easily exceed a gigawatt. They can be meshed together for higher airspace density. 
Sadly, the video camera was left behind today; refer to the attached sketch for geometric clarification & the video will catch up soon.

Dave Santos of KiteLab


*COTS : commercial off-the-shelf