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Crosswind Kite Power at Texas AWE Encampment in October 2013

At last, this 12 second proof-of-concept video* emerges from the TX AWE Encampment:

Using a stock 7 sq meter NASA Power Wing piloted by a human kite master seated at a pilot station with a MegaBar in his hands, we have made the world's cheapest demonstration of pure crosswind kite power. No Yo-Yo, no retraction phase, no need for down wind airspace, no carbon fiber, servos, nor sensors.  The design is wonderfully scalable: Just add more kite, a bigger generator and a cushier seat  :^) 

The kite engine is built around a flip-flop double-freewheel bicycle drive train.  When the kite goes left is spins the generator; when the kite goes right, it spins the generator. An artisan built concrete flywheel smoothes out the turn around for even power output. The steel cable is anchored on either side 4 ft deep into the Earth and tensioned by a large come-along. The kite's control lines feed through a kPTO (kite power take off) which is a triple racing block on a zip-line trolley connected to a secondary cable way by means of a jumper. The secondary cable way makes a loop through 4 pulleys with the kite engine in the middle of the loop. Simple and brilliant. Mounted on the kite engine is a 48v generator, belt driven from the flywheel. 

For AWEfest 2014, an optimized system will feed into our micro-grid, along with the imputs of Rock The Bike, and all the aggregated inputs of the open source, DIY kite power community.

*please excuse crude videography.      ~
  • CC BY NC SA     ~ AWE Encampment 2013 team       29Oct013              Discuss at: airbornewindenergy10485

Comment and development of this topic will be occurring here.       
All, send notes, links, drawings, papers, videos, plans, safety-critical findings, and photographs!

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    • Wright Brothers' Moment at Texas AWE Encampment
      The slack wind and brutal heat of summer has passed at the AWE Encampment, with hundreds of odd technical details worked out in refining a crosswind-cable AWES kite-farm demonstrator.

      Today was good wind on a beautiful day. We hooked up a new beast, a double-stroke groundgen, which had only turned fitfully before, in sucker-wind. Some mysterious last kink in the machinery had been binding it up; big power just wasn't flowing thru the drivetrain. Sitting far out in the field, the problem could not be easily found within the Willy Wonka guts of the contraption. We chose and launched a NASA 7m2 NPW, which fired-up with characteristic power. Working the MegaBar, the machinery creaked into pathetic slow-motion. A nice puff surged the kite, then a wonderful little "sproing" was heard. Suddenly the freed machine whizzed into sustained high-speed generator driving.

      The key technical accomplishment is that this true Low-Complexity Crosswind-Power, at a high TRL, with no downwind reeling, and only a brief moment of slack as the kite tacks at each end of its crosswind cable travel. With the flywheel spinning madly, tacking barely slows the machinery, and the power output is clearly far flatter than the jagged sawtooth traces of all the turbine-on-a-wing and long-reeling pumping crowd. Videogrammetry will confirm we got about 1800 rpm out of the open-circuit generator (DC industrial motor in gen mode) that we estimate capable of ~10 kW, continuous. Ed took video during the magic moment, to be shared promptly.

      Our next task is to record actual power curves with a fully loaded generator. We have far larger kites to fly, up to 32 m2, and a lot more seasonal wind coming. It will only get better, but for us this will be remembered as a "Wright Brothers moment", or like a wildcat oil-well coming in as a gusher. 
      ~Oct 29, 2013.   ~ Dave Santos


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