Excellent point on the lightning issue allthough now you just triggered the Gerble in my head spinning on some new ideas on how that power could be harnessed. My dad worked with some folks who had made some attempts many decades ago but I just had an idea that they may not have tried regarding the many ways to store and convert energy. I'll keep you posted.

-brooks (and the gerble that controlls him)

Mike,   The referenced post was a semantic abstract, not a technical specification. Specs are available online off JoeF's AWE site.   If you are asking about Lifter Kites, standard types like Morse Sled & KiteShip's OL are used. Specs are published. DaveC or i can answer specifics.   If you are asking about Membrane Wingmills-

Hi Brooks,
 
 
You'll need some incredibly large capacitors to store a charge of lightniing . . . . or even multiple strikes.
 
 
Harry
 

---

To: AirborneWindEnergy@yahoogroups.com
From: brooksdesign@peoplepc.com
Date: Mon, 6 Apr 2009 18:42:15 -0600
Subject: RE: [AirborneWindEnergy] Cheap Practical AWE

Mike,   Whoops, forgot your wingloading answer-

When I said "new ideas they may not have thought of " it was a hint to the common method of extracting/storing energy via direct electric energy is not the only form of energy that can be extracted from a lightning strike. Giant capacitors would probably be the most efficient if they could be charged fast enough to absorb that energy but as someone who has restored old buildings with damaged lightning rods I can tell you energy can be take many forms. I'll have to check my my chief number cruncher to see if the projects he worked on could do the job as well as the methods that have been tried by the electrical extract/storage method. There has been some research in the direction I'm thinking but not public common knowledge. I'll have to check on how public before I say more.

-brooks

The fatal problem with lightning power is low capacity factor & high capital cost of the equipment, which overwhelmingly sits idle but has to be massive to handle brief peaks.   Persistent atmospheric charge across altitude seems too diffuse to usefully collect by any sort of flying conductive web. Convective cells are big capacitors & might conceivably be discharged at a reasonable capacity factor (pulsed ionizing energy beams)?, but not anytime soon.   Synthetic lines in a non-saline atmosphere are not lighting attractive. Aerostats have woven metal jackets on their tethers to handle lightning. Lightning arrestors are bypass conductors that will protect a kiteboat or ground generator from damage.   Ultra capacitors are generally only cost effective as load/supply leveling  buffers, not as primary storage. Composite structure can double as capacitor. Ultra capacitor airframes might charge/discharge by contacting along skycable networks.   Wind power AWE will be far more practical for a long time than secondary energy harvests such as from solar thin-film or static-charges. Piezo hummer ribbon mesh might be a "solid state" collector someday. A wing yanking on a generator is current best option.

No debate here on all these points, Harry just got the Gerble running on that treadmill in my head but I have some new ideas on the storage and transmission of energy. Actualy old ideas revisited with a twist.

-brooks

www.carbonconcepts.co.uk/downloads/genbroch0306.pdf

Although turbine inspired, the Betz Limit is presumed here to generally apply to any crosswind scheme according to its InFlow "footprint". A maximized KiteField of a given InFlow AirSpace needs to sweep its footprint as thoroughly as possible. Schemes were a little kite sweeps a big sky let a lot of capacity by, very low Betz.   Naturally any AWE array we can envision will have modest Betz performance compared to a turbine, probably around 20% extraction gives best ROI. That KiteMesh methods best fill a given "high-altitude" InFlow AirSpace is conjecture.

Dear Dave,

Attachments :

  I think the entanglement problem and no-wind problem could both be solved by using a very large train track loop as apposed to a carousel. Instead of having a bunch of physically linked cars to keep them spaced(too much power loss in friction to the dummy spacer cars) you could have each car have its own hybrid generator that when being pulled it would feed electrical power into the tracks and the on the upwind portion (and no wind)they would receive power from them. The track loop could be huge (many miles)and would not even need to be completely circular in fact a section the ran fairly straight in the direction of the most common prevailing wind would be most efficient. There could even be connecting tracks that could have other directions as straights for the different seasons, as well as side tracks for parking individual cars for maintenance and a launch/landing field.

  The robotic issue would not be nearly as difficult with the ability to have spacing greater than the line length to solve the entanglement problem as well as just having them at such high altitudes that the system would have plenty of time to react and recover plus each car could have its own kite pilot that could control through RC link to on kite control surfaces powered by minimal on kite generator.

-brooks

________________________________________
PeoplePC Online
A better way to Internet
http://www.peoplepc.com

  It also just occurred to me that a sea based system could work with large battery tankers being towed by the kite and dragging the turbines or flippers for generation as has been suggested and the Dave S has already proven it is possible to have wind powered watercraft that sail directly into the wind (hey dave, I won another bet with the engineers at work last year on this, it never fails to amaze).

-brooks

Within the not-too-distant future it may be possible to use flexible photovoltaic material tomake kites and/or balloons. The combination of airborne wind power plus airborne solar PV conversion could become an attractive and cost-competitive technology.
 
 
Harry
 

---

To: airbornewindenergy@yahoogroups.com
From: santos137@yahoo.com
Date: Fri, 10 Apr 2009 23:02:51 -0700
Subject: [AirborneWindEnergy] UAV Reliability Study

Dear Harry,

Dear Dave,

Chris,   Agreed, reliable is feasible, but not cheap. Kite Energy is predicted by some to be  "cheaper than coal", but reliable UAV's, while possible, are very expensive & will not pay for a long time.   Airliners are now safer than the home bathtub, that's how safe UAVs must become in the NAS, as the first (safety) study asserts. At an order-of-magnitude UAV reliability improvement per decade, that's twenty years & still may not be cheap enough.   So low-mass-aloft passive-control methods have a big window & may dominate, on cost basis, even after UAV refinement. UAV path may be the kiss-of-death as a biz model.   Its nice to have a passive low-mass solutions in hand,   daveS   PS to list- "Low Reynolds" nemesis theory is just half of small UAV extra unreliability, small scale is a faster regime, realtime control is a bigger problem.

Hello Chris,
 
 
The concept of airborne piezoelectric conversion on flutter kites certainly has merit. Based on experience in low power generation (under 5kW), piezoelectric conversion has shown to be more efficient that small wind turbines. I can certainly envision a potential market for airborne piezoelectric flutter kites in remote communities.
 
 
Regards,
 
Harry

 

---

To: AirborneWindEnergy@yahoogroups.com
From: christopher.m.carlin@btinternet.com
Date: Sun, 12 Apr 2009 03:45:42 +0100
Subject: Re: [AirborneWindEnergy] UAV Reliability Study

---

Internet Explorer 8 makes surfing easier. Get it now!

Challenges to Piezo-Kites include-

Actually piezos need not but operated at ultrasonic frquencies to function but I do agree that the latice would be problematic and there is always that long cable issue. A ground based piezo based generator system would not be out of the question as a simple way to extract pulsing power without the need for the sprag ratchet and flywheel. I can easily see stacks of piezo elements outperforming a standard mechanical gen in investment cost and mainainance. A good article in Scientific American has a DIY on making them from Silicone sealant.

-brooks

________________________________________
PeoplePC Online
A better way to Internet
http://www.peoplepc.com

Do you have a reference for this article, Brooks? Date and page, maybe? Or even a URL? Thanks!

Dave

It was mostly focused on the flexable actuator aspects but I know I have the zine in my stack, I'll dig it out and get back to you.

-brooks

Brooks,   Of course piezo works at low Hz, but its like driving a sports car in a hospital zone, so "driving every piezo element at very high Hz to approach its thermodynamic limits" is clearly best kite mass-to-power.   it seems a fundamental tradeoff- best piezo scale v. viscosity, bulk piezo grows too massive (quasi 3D (or fractional 2.n D) faster than good wings grow in area (quasi 2D). a pocket piezo AWE kite would be a cool milliwatt charger, but where do you get piezo kite fabric?    ds

____________ _________ _________ _________ _
PeoplePC Online
A better way to Internet
http://www.peoplepc .com

Piezo textile? Some paths:
http://tinyurl.com/piezoelectricTextile8888Lift

Consider using aloft piezo gains to run smart matters aloft while resulting kite-line dynamics run ground-based energy generation.

Lift,
JoeF

Grant,   On the advice of Professor Viswanathan, who attended the recent University of Texas AWE seminar, KLD Energy Technologies of Austin, TX, has approached our community about the kite energy application.    They have breakthrough thin-film nanocrystalline tech motor/generators & advanced controllers to provide a new efficiency standard in a low RPM, high frequency, transmissionless motor/generator tech.   www.kldenergy.com Note- the website features only initial motor tech, the generator dev effort is underway behind the scenes, expect big news soon.   Several of us AWE hackers are lining up as beta testers. Brooks is first in line, with a major project underway, & is local to the Austin-based company. Contact this list with a few details if you have a cool project in the 10kw range (200kw projected) that might be a good showcase for the new generators.   dave santos   KiteLab Ilwaco, WA Austin, TX

Try googling "scaled composites." They are mostly in the aircraft/drone business but a fairly innovative free wheeling outfit good at pursuing government money. They might be interesting to work with. Also find out who built "Slam" a big catamaran for Larry Ellison. It was built in Anacortes by a shipyard but involves some really fancy carbon fiber work. The mast is essentially a 150 foot high aspect ratio wing - could just as easily be a windmill blade. I imagine they could work to any scale you prefer.

Not Quite in the states but interesting and lite.

http://www.theinventory.orconhosting.net.nz/smartdrives.htm

http://www.youtube.com/watch?v=4vSD8z4fzNg

New file:
http://www.energykitesystems.net/airspace/index.html

When anyone gets a related link for a nation's airspace regulation--especially relating to AWE uses, please send such to me for posting to the above file.

AWEsome use of airspace,
JoeF

Few points:
1. I wonder how many kite-flying sessions have occurred in a manner in the world where a NOTAM may have been urged by the procedures of the various involved nations?

2. Finding local NOTAMs may be challenging for those unpracticed in finding NOTAMs.

3. Here is a doc for procedures related to Canada:
http://www.navcanada.ca/ContentDefinitionFiles/Publications/NOTAM/NOTAM_Manual_en.pdf If this link breaks, copy/paste the full string carefully into browser. Adobe Reader is free online to read the 127 pages.

4. http://www.faa.gov

5. AWE participants are invited to e-mail me with links and comments for any nation's airspace for the following file:
http://www.energykitesystems.net/airspace/index.html

Lift,
JoeF

== Dr. Eric Schmidt, Chairman and CEO of Google Inc: 

My laconic capsules from his presentation:
    Smart grid needed now. And energy efficiency as resource now.  Performance-based standards for energy efficiency. Plug-in hybrids. Smart meters for homes. Open systems. Open standards. Fund university R& D.  Patent reform. Energy...need to get it right.  Engagement. Encourage debate. Embrace all.  Use the crowds.
  Vid2(48 MIN)        

 

 
FlipperWing of February 2009, made and flown by Dave Santos.

It seems a bit tricky to post online an image that will show online. This method for this post begins by choosing the New Beta Version of the editor offered. Then a small checkbox for "View HTML Source" can be checked to get to the HTML code where the special SRC tag is used with a carefully constructed URL made after one files in Files an image file with its image filename suffic appropriate to the image.   Here on this test:

<IMG SRC="http://tech.groups.yahoo.com/group/AirborneWindEnergy/files/2009febflipper.jpg"

was in plain text placed in the HTML view of the posting effort.

End of test.        We yet need to test if motion files will work.

Cheers,

JoeF

All, if you do not have an easy web space to store sharable images and files, then send them to me and I will open a folder in your name and place the files and images in the folder. I will give you a list of the absolute URLs for the image files and document files. Then in your discussions and e-mails, you may simply copy/paste the full absolute URL in your paragraphs. The base domain will be http://EnergyKiteSystems.net/

For example, here is a file in a folder named after David Shepard:
http://EnergyKiteSystems.net/DavidHShepard/index.html

When your folder gets several items, then I will form an index page from which you or your visitors may click to any or all of the files that you have placed in the folder.

Steps:
Send me some images and documents.

And you may send me replacement documents that overwrite an old version. Documents can be plain text, PDFs, Word documents, jpg, gif, avi, mpg, png, html. I can convert Word documents to PDFs for a wider readership.

The free service is to support the rapid development of airborne wind energy.

Another example:

http://EnergyKiteSystem.net/DaveSantos/kitmot5b.mpg

is a short motion file in one of the member's folders.

Best of lift to you and yours,
Joe Faust

To illustrate a common path to typo errors regarding URLs,
please note :) the typo in the mpg file example in the prior post. To avoid such typos, there is a popular recommendation to achieve getting an URL in a browser line with proof that the URL is working. Then use mouse select tool or equivalent to copy the successfull URL to one's clipboard and then paste that full URL into the text of a post or e-mail; such practice avoids what just happened.

Here is a tested URL to cover the typo whre an "s" was needed.

http://EnergyKiteSystems.net/DaveSantos/kitmot5b.mpg

This was was tested in a browser and the file was called.
Then I copied and pasted the working URL to avoid the typo error.

Enjoy the kite motor video.

Joe Faust

Looking at one of Dave Santos' kitemotor launches before the lifter actually lifted the kitemotor left a rod wobbling on the ground; that gave me a flash idea that I sketched:

http://EnergyKiteSystems.net/JoeFaust/AWE/leverwaft.jpg

We will see variations of this at KitePorts around the world.

Joe Faust

Good Eye, Joe.    Your "Wafting Lever" is best-yet geometry, horizontal-axis (downwind-axis) crosswind-power, keeps gen on ground, etc..   We've been wafting our lever/crank schemes (Kite Gen, WPI, MarcR et al, KiteLab, etc.) in the wrong planes!     Notes-   Guessing best Wafting Lever crosswind plane slightly tilted upwind   No active control required for Wafting Lever; to drive SingleLineKite (SLK) can passive "hunt" (small sweeps) or a FlipWIng under a lifter can sweep fast & wide.    Single Anchor w/ vertical pivot base will work, use downwind wheelbase to counter lever torque

This note from Dave Santos
seems to fit this thread:

http://www.EnergyKiteSystems.net/DaveSantos/hisweep.mpg

Attached FlipWing video taken at low altitude in the gusty lee of a hill, these wings run like a metronome in a steady breeze to pump or generate electricity. This wing & lifter kite made from Tyvek to crank a small generator. Now able to passive control sweep of Membrane Wing-Mill to cover whole kite window. The tack speed is also passive controllable, a bit fast on this wing.

Cross-Wind Power without active controls!

daveS
KiteLab


======================================================

Using Dave Santos' nomenclature furtherance from his e-mail forwarding we get evolution from bare wafting lever to controlled kite driven "tipping boom" and even ballasted "dipping boom." And the distant anchoring of kite line can use less ground by bringing the anchor right at the grounded generator. Some forward downwind wheeling might be involved in some variations; let the driven shaft free-sit in the wheel. Trussing the boom might reduce ground use and provide firm hold of driven shaft. Dave Santos suggested ballasting the boom for improved kinematics. I now would like to suppress "wafting" and reserve "wafting" for less-controlled wings in wind, like an energy-generating wafting vertical wing or wind-buffeted high broad fence, etc. I rather like to move toward Dave's "tipping boom" where the crosswind power drives the boom to tip one way and then the other.
A second sketch begins to bring only some of this forward:

http://EnergyKiteSystems.net/JoeFaust/AWE/ballastedtippingboom.jpg

Capture both directions of the crosswind drive via a sprag clutch complex. The perpendicularity of the drive to the driven makes for efficient coupling from one energy field to the generated energy field.
Collaborative effort in open-source ...

Hello from a new member.
I'm investigating into computer vision (I am a programmer) as a way to govern a kite system .
As I guess this is a minor problem compared to hardware setting I am here to ask for guidance.
I need to figure out what sort of servo motors configuration is needed for flight  control of a 10 square meters kite from ground.