[Rick Masters]

Some of us were discussing the influence of a keel on the power obtainable from a sail at
http://ushawks.org/forum/viewtopic.php?f=2&t=2095&start=60&sid=e466a3c2dd3980e6dffae66f1f05fca9
Here is the flight analog of a "perfect keel" - a simple tether - and the amount of energy that can be captured.
Any two-line kite fighter will recognize the power that can be generated on a horizontal run perpendicular to the wind.



The company below has computerized the controls to pay out a winch-driven generator to produce electrical power.
They claim a 400 square meter kite can produce 2-megawatts. This could be a game changer.














Even Leonardo da Vinci and Benjamin Franklin wanted to take advantage of the power of the kite. Engineers of today are almost to the point that they can catch the winds more than 300 meters above the sea, thanks to the development of materials, computer and drive technology because there can be almost twice as much energy to harvest as there is near the ground - and the winds blow steadily. About 70 companies worldwide are working on different solutions, about half of which could present a marketable system within the next three years, estimates the Federal Association of high altitude wind power of Germany (Bundesverband der Höhenwindenergie).
http://www.ndr.de/nachrichten/hamburg/Hamburger-Drachen-als-Energiefaenger-am-Himmel,skysails126.html

[JoeF]

Search with parentheses in Google for Web and then also for "Images" with

"Working kites"
"Energy kite systems"
"Kite energy systems"
AWES Airborne Wind Energy Systems

If one is interested in tech of the field: Join free the discussion group: airbornewindenergy

Info site:
http://www.energykitesystems.net/AWESMuseum/index.html

[Harry]

This could be a viable alternative to the current wind farms we have here in Wyoming.
Currently, the local wind farms produce a lot of noise and kill many bats and birds (like eagles).

If the kites can get high enough, perhaps they can be less hazardous to the local wildlife. The only other hazard would be taking down aircraft passing overhead, or aircraft making approach to local airport.

There's just no winning, is there?

[Rick Masters]

    I believe this is the technology that will replace wind turbines. There is presently a great deal of success in stopping turbines when wildlife approach, using automated optics and radar. The kites can be flown out of the path of birds, aircraft, you, all by an automated process. To recognize the opportunity, one need only to read the comment above stating a kite system utilizing two 400 square meter kites can produce 2 megawatts .
    If a turbine can be placed in a good wind zone, it can deliver an average of one-third its placard rating. Therefore, a one-megawatt turbine can deliver 333 kilowatts. So an array of six one-megawatt turbines could be expected to deliver two megawatts output. Six one-megawatt wind turbines cost about 9 to 12 million dollars. A two-megawatt yoyo kite system could probably be built and operated for a year for a tenth of that.
    There is a practical limit to height because drag on the line works against efficiency. Once past a certain altitude, there is no reward in going higher. I do not have the formula for this.
    I suspect that working the yoyo kites in the compression lift of a ridge would be about as effective as going for higher altitude.

[Bob Kuczewski]

Very promising indeed.

Is this a real photo??

skysails119_v-vierspaltig.jpg (46.24 KiB) Viewed 8396 times