Suspending Wind Turbines from Kites - Technology Evangelist

Robert Cringely penned an article on PBS a few weeks back about a company that has a creative way to improve the efficiency of wind generated power. Rather than using windmills, which rarely run at full capacity due to inconsistent wind at typical windmill heights, why not use ginormous kites to raise windmills up to heights where winds are consistently strong?

Oh, and We Also Saved the World

What's cool about these tethered tensile wings, he explained, is that they can be designed in such a way that no aircraft fuselage is needed and yet they can lift (vertically, straight from the ground, no runway even required!) enormous weights. And I mean ENORMOUS weights, like a thousand tons. A fully loaded Boeing 747-400 weighs about 400 tons, so a THOUSAND tons would change the nature of airfreight.

But there's an even better application for this technology than airfreight, he explained, electric power generation. Build a gigantic tethered tension wing and power it with electric motors mounted in the leading edge of the wing. Send the electricity to run these motors up the tether, itself. The wing will take off vertically and once it is at the end of its rope, so to speak, can be made to circle thousands, or even tens of thousands, of feet off the ground without a pilot or any sort of crew.

The idea has intrigued me enough to try it on a much smaller scale. Can I lift a windmill with a kite I handle myself?

I've started researching the concept, and am trying to do this on a relatively small budget. As a first attempt, I've ordered a kite off Amazon that's apparently capable of pulling a kayaker a few knots faster. After discounts, that came to around $40.

Now I need a wind turbine that I can attach to the kite. A little searching dug up this model, which happens to be sold by a company within biking distance of my house. That seems workable, but I'm open to suggestions on other wind turbines that may be a better fit for this test.

The next decision is whether to draw that power down the line in a Ben Franklin like fashion, or power some lights attached to the wind turbine. The latter is probably easier, but the former is closer to replicating what Makani Power is trying to do on a much larger scale.

What do you think? Does the kite I've chosen have any chance of lifting a wind turbine? Will the weight of a copper line running between the kite and me be too much weight for the kite to handle? Will my hair stick straight out when I'm successful?

You need a Single Line Kite designed for lifting. You have ordered a multi-line power kite. Contact The American Kitefliers Association at www.aka.kite.org for information about the proper kite equipment. The Kite Aerial Photography group with in the organization have been lifting equipment from kites for years.

The Makani concepts may conjure up the mental image of a wind turbine hanging underneath a big kite. But if you read the details a little more carefully you will see that the kites will not be in a stable position like a toy kite but rather flying in circles at high speed - the kind of motion that a broken toy kite might get into for a few seconds before it comes crashing down.

The speed of flight can faster than the wind speed by a factor of up to the Lift/Drag ratio of the wing which can be around 20 or more. That's fast - hundreds of miles per hours. At these speeds you don't need a big turbine. It can be a tiny propeller attached to the kite that spins at very high speeds. The power to weight ratio can be orders of magnitude better than conventional ground based wind turbines.

The catch? Flying a kite at high speeds in circles requires advanced control algorithms, constant monitoring of wind direction and accelerations and adjusting the angle of attack. Keeping a circling kite up in the air for months or more is definitely not trivial.

i have flown a toy kite over 20000 ft already ill do it again
i lifteda3.5 lb camera the tree line overthe tree line however the risk i didnot want it to break until i have a new camera
my two dollar kite that came with a two hundred yard string well i switched the string with my string witha 6700 yrd line

if the kite had other tandom kites with solar power material and umbilical line atatched to each one and back to the ground to a generator or plant to recover the energy and send it out

get a hold of me celrods@aol.com i can fly kite s any where and all the way to the international spacestation (i think that is about two hundred and fifty mile

if the kite had other tandom kites with solar power material and umbilical line atatched to each one and back to the ground to a generator or plant to recover the energy and send it out

get a hold of me celrods@aol.com i can fly kite s any where and all the way to the international spacestation (i think that is about two hundred and fifty mile

I don't think you can get a more outlandish headline than "windmills from kites" if you tried. :)

How about wave generators? They've piqued my curiosity for a couple years now. 800 times greater energy density than air and constant wave motion makes it attractive.

I think the kite turbine is a good idea however to build a realistic model you would probibaly have to build one from scratch. Maby an aluminum framed sled type kite and a lightweight high output car alternator would get you started to generate a usable amount of power. It would probibaly be cheaper to build one too.

Comments

1. Posted by: Sue on November 27, 2007 8:02 PM:

You will either attract lightning or you will manage to hook up to a power line. Either way- More power than you really need.

You could just buy a large Power Kite and use it to pull your toyota Prius around and regenerate that way.

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