Jerker Line Systems as AWES Carousel or Track
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
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Comment and development of this topic will be occurring here.
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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
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
[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
*Loyd, Culp, Santos, Stuart, and Bolonkin
~ Dave Santos, 4Feb2013