We had partly reinvented the ideas behind Stangenkunst and Jerker-Line networks, but thanks to our amazing friend, Kris de Decker, of Low Tech Magazine, we now have a trove of prior art, a complete design pattern language, for how to create large kitefarms of many kites driving a central generator.

We would drive our jerker-line networks "backwards" in a fan-in mode. Jerker-lines clearly beat the scale-limited high capital cost and inherent fouling risk of giant kite carousels and elevated kite vehicle tracks. While the historic jerker-line similarity cases were generally low powered (20-50 hp typ), there is no mechanical detail that does not scale greatly, as related urban cable car and ski-lift systems in the MW range also indicate. Cable loop systems remain a kite farm contender, but jerk-lines clearly can do hard work for many decades of service.

The key kite method to master is synchronized sweeping, but we know how this is to be done. Its also wonderful to contemplate how flexible and robust a kite farm can be, by flying the "fleet" of kite cells in endless combinations, changing sails, and bringing units on- and offline. A single massive generator at the center would enjoy full economy-of-scale and run consistently across a wide wind range. Adding an aux pony generator would be nice too.

One old reference in particular teaches us the art. Find the link on the Jerker Line Systems Part Two reference list-

Surface Machinery and Methods for Oil-Well Pumping", H.C. George, Bulletin 224, Bureau of Mines, Department of Interior, 1925.

That these sorts of legacy mechanical networks can be driven by kites is CC BY NC SA

• CoolIP* and CC BY NC SA        ~Dave Santos        4Feb2013             AirborneWindEnergy/message/8517

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

• Terms and aspects:   
  • jerker-line system
  • Stangenkunst
  •  
• Related links and concepts:

  • February 02, 2013 
    The Mechanical Transmission of Power (2): Jerker Line Systemsa

    January 23, 2013
    The Mechanical Transmission of Power (1): Stangenkunst

• Commentary is welcome:
  • We don't know BobS's result yet, but our our famous friend, Russian scientist-dissident AWE theorist, Alex Bolonkin, provides us a "fifth" reference* on polymer cable v. electrical conductor transmission potential. 
    
    High speed rope-driving is an extreme case of the famous Newtonian formula- f=ma . I heard the "Nuke Plant rated power (GW scale) over a ship-hawser" comparison from Dave Culp, of KiteShip, who calculated separately. My own crude example is that a common cotton sewing thread can convey about a horsepower or more at 200 mph. 
    
    Since the 1980's we have had a true superfiber- UHMWPE. A few other fibers come close, but none has so many good properties (non-toxic, recyclable, UV resistant, etc). We must once again master traditional high-speed rope-driving, but in the sky-
    
    Bolonkin on the subject (edited slightly)-

    "Cable Transmission of energy from a wind rotor at high altitude to an electric generator on the ground.

    In the (Example AWES), a polymer cable transmission is proposed. Such a transmission weighs about a thousands times less than copper electric wires of equal power. A wire having a diameter >5 mm conducts 1-2 ampere/sq.mm. If the electric generator produces 20 MW at 1000 V, the wire cross-section area will be 20,000 mm, (wire diameter 160 mm). Cross-section area of the cable transmission of equal power is only 37 mm (cable diameter 6.8 mm for cable speed 300 m/s and working load 200 kg/mm, see Project 1). The specific weight of copper is 8930 kg/m, the specific weight of artificial fibers is 1800 kg/m. If the cable length for altitude 10 km is 25 km the double copper wire weighs 8930 tons (!!), the fiber transmission cable weighs only 3.33 tons.  It means the offered cable transfer of energy of equal length is easier in 2682 times, than copper wire.  While copper wire is very expensive, artificial fiber is cheap.

      

    All previous attempts to place the generator near the rotor and connect it to ground by electric 

    transmission wires were not successful because generator and wires are heavy."

    [Note- Small scale AWES of a few watts are a nice exception to poor flygen performance. At this scale, safety is not an issue, and thermal dissipation is so good that power-to-weight ratio is much improved]
    http://arxiv.org/ftp/physics/papers/0701/0701114.pdf
    *Loyd, Culp, Santos, Stuart, and Bolonkin                                                                ~ Dave Santos, 4Feb2013

     

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