## Re: [AirborneWindEnergy] KiteGen

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• ... Chris, et al, BTW, regarding the ever-presence of wind at 600, this does seem a little surprising, but I guess one would have to quantify at what speed
Message 1 of 15 , Apr 10, 2009
Re: [AirborneWindEnergy] KiteGen
At 4:24 AM +0100 4/10/09, christopher carlin wrote:
Dear Dave,

Interesting - I find the statement that wind at 600 meters is nearly always present a bit surprising unless they has some specific location in mind.

Regards,

Chris

Chris, et al,

BTW, regarding the ever-presence of wind at 600, this does seem a little surprising, but I guess one would have to quantify at what speed wind qualifies to be termed "present"?

Along these lines, one interesting aspect of this scheme is that it has kind of a built in answer to the ever present kite AWE nemesis of "what do you do when the wind dies";  at the expense of a putting a little energy back into the KiteGen, it can be rotated slowly to keep the kites aloft under no-wind conditions (like when we try to launch a kite by running with it under insufficient wind conditions :-)). This might go a long way towards making a KiteGen self maintaining 24-7 (of course, you still have to get it started that first time.....maybe using jettisonable natural gas balloons).

FYI, below is a thumbnail assessment of KiteGen I did a few years back (note, it was called KiwiGEN then). I rated its potential relatively high amongst other candidates.

DaveL

The KiwiGEN

Description and Overview

This scheme is a horizontal, rotating carousel with kites attached around the periphery. The vertical axis of the carousel is a shaft that drives generation equipment. The kites would be robotically controlled for autonomous operation, and maneuvered to provide high tangential load on the ³down-wind sector² of the carousel to maintain rotation rate for power generation; kites on the opposing (up-wind) side would fly maneuvers conducive to minimizing torque that acts to impede rotation. The types of maneuvers required would depend upon the type of power-kites employed. Kites could possibly be stacked for additional power density for the installation.

This scheme seems to present a very favorable potential for autonomous operation, although the robotic control of the kites is a challenge. To produce maximum power, kites would be of the ³traction² variety (used for kite surfing, buggying, etc), or, other specialty kites such as derivatives of the Revolution design (from Revolution Enterprises). The Revolution is attractive because of its strong pull and extremely tight controllability, an attribute highly desirable for robotic automation.

By it's very design, the KiwiGEN can have virtually total immunity to wind azimuth variation. Such immunity may be implemented differently for each type of kite used, but implementations would be enabled by the azimuthally-symmetric aspect of the design (ie its 360 deg symmetry about an axis vertical to the ground). The no-wind situation can likely be handled gracefully via schemes varying from active buoyancy (via a few closed kite-cells containing light gases for traction kites), to, actively rotating the carousel to create artificial relative wind for in-air kite stowage (a low power expenditure mode while awaiting resumption of practical wind levels), to, kite stowage at the periphery of the carousel (for hard kites such the Revolution).

The ground station seems to present no particular difficulty, and is reasonably compact. It is not clear what flight altitudes may be practical for the kites since, the ratio of ³kite altitude² -to- ³carousel diameter² may be a critical design parameter in achieving successful, non-interference of kite trajectories under robotic control; while traction kites can be flown in fairly tight quarters (as in buggy-racing) and still maintain non-interference, such maneuvering is done under the watchful, intelligent surveillance of the drivers, who perform (what may be frequently clever) coordinated avoidance maneuvers. A reliable robotics equivalent of this may be hard to achieve given random wind disturbances.

The system seems inherently safe, given that such installations would be protected against casual human interference.

Scaling up power can be done via two generic approaches; (1) Larger diameter carousels, and (2) Stacking of kites. Approach (1) allows for a number of amplifications such as, (a) larger torques (b) more kites around the periphery, (c) larger kites, (d) kites at higher altitude, etc. There are a number of curious effects associated with scaling the KiwiGEN. The increasing of diameter and expected power benefits are subject to a number of physical realities, such as:

1. The system would not be expected to generate power if  the peripheral speed (ie. tangential velocity) of the rotating carousel exceeds that of the ambient wind speed; to rotate under these conditions would require the KiwiGEN to provide power to, rather than extract power from the environment.

2. As rotation rate (RPM) increases, power increases, but so does peripheral speed. This has two detrimental tendencies (a) it decreases relative wind on the kites in the down-wind sector, and (b) it increases relative wind on the upwind side. Note also that since aerodynamic force varies as the square of relative wind speed, this has a potentially doubly damaging attenuation on net torque.

3. As diameter increases, torque due to kite load increases; also, this allows more kites can be flown at the periphery. Both serve to improve power output.

All of the above effects are inherent in the operation of the KiwiGEN and have been included in a rudimentary power simulation to examine power output of the KiwiGEN as a function of RPM and Diameter for the purposes of this report.

Specifically the effects included are:
- relative wind as the difference of wind speed and carousel peripheral speed
- kite force dependent upon Dynamic Pressure created by relative wind (V
2 effect)
- tangential kite forces depending upon number of kites (one added every 20 m)
- net torque from combined kites as a function of diameter
- power as a function of torque and rpm

The graphs on the next page show the outcome of this simulation. Note that

1. The dark red plateau (of zero power) is the region where RPM & Diameter combine to produce carousel peripheral speed greater than the wind speed (ie. producing zero relative wind on the Power-side).

2. The quantum steps in the power surface are because of the simulation of discretely adding kites as the circumference grows with diameter.

3. By  imagining (power surface intersections with) vertical planes at constant RPM or Diameter you can intuitively see what is going on with the KiwiGEN (said intersections can also be seen in the "wire-frame" drawing-artifacts  of the 3-D plot).

For instance you can see that at high RPM, increasing diameter quickly leads to zero power output (dark red plateau). Or, for a particular diameter (say 50 m) power will maximize at some (lower) RPM, and if RPM continues to increase, power will go to zero (the dark red plateau again).

Also note (not shown in the graphs below) that as diameter grows without bound, the power output will eventually drop to zero. Where this occurs depends upon the ambient wind.

For the graphs shown, the ambient wind is a uniform 25 knots; at this wind speed, a 100 m diameter carousel will still be productive, given that it operates at about 1 RPM.

Note: for simplicity, these power profiles were derived assuming "straight-pull" type of kite load generation, rather than execution of more complex power maneuvers (figure-8's etc), thus the pronounced power degradation when tangential velocity of the carousel approaches wind velocity,

Below is a contour plot showing the power topology for the KiwiGEN corresponding to the 3-D plot above.

Strong Points:
a.   System is essentially immune to wind-azimuth variability.
b.   Simple mechanical design.
c.   High potential for autonomous operation.
d.   Relatively easy to scale power output (to within limits).
e.   Environmentally benign.
f.   Power output more than adequate for consumer usage.
g.   Power output may be practical for  municipal usage.
h.   May realize per-Watt cost superior to conventional modern wind-mills.

Weak Points:
a.   Potentially difficult robotics challenge.
b.   Possibly a lower limit on power scalability for small consumer needs.
c.   Reliability may be problem regarding no-wind conditions.
d.   Potential for kite entanglement may be problematic.

Detail Assessment

Max  kW  Potential:  Given a Good rating because it can be expanded over a possible broad range of application (albeit, maybe not to the level of sustaining large municipalities). Certainly it could be applicable over the upper range of consumer users, and even for small municipalities and generation Farms.

Scalability:  Given a Good rating because the general scalability seems quite good across a possibly large range (excepting possibly a lower and upper practical limit).

Practicality:  Given a Fair rating because the scheme will require some possibly complex robotics mechanisms, and there is potential for kite entanglement and issues of no-wind autonomy.

Potential for Autonomous Operation:  Given a Good rating because the system has a natural immunity to wind-direction variability that is unique amongst all the methods examined. There is a possible problem with the no wind situation, however, there are a number of possible (untested) solutions for that. Kite entanglement could present a problem, but that can be dealt with by trading power (ie. kite density) for entanglement immunity.

Manufacturing Cost:  Given a Good rating since once designed and tested could prove to be quite economical to produce.

Prototyping Cost:  Given a Good rating because of the apparent simplicity of doing a proof of power-production prototype that does not employ robotics control of kites (ie it uses humans to execute the kite power-maneuvers). While the robotics challenge would remain un-prototyped at that point, once power production were proven, then the impetus to move to the next stage of development could be successful, thus accomplishing the intent of initial prototyping.

Complexity:  Given a Fair rating because while virtually all aspects of the system would be fairly straightforward, the complexity of the robotics challenge looms significant.

Safety:  Given a Good rating. Likely no significant safety issues.

Environment  Given a Good rating based on minimal environmental intrusion. The while the carousel will consume some  real estate, the kites themselves should be fairly unobtrusive and the system quiet of operation.

Accommodating Wind Variability:  Given a Best rating because the system is naturally immune to wind-direction variability; this is unique amongst all the methods examined. There is a possible problem with the no wind situation, however, there are a number of possible solutions for that (albeit untested).

Probability of Demo Success:  Given a Good rating because this prototype should be fairly simple to devise. If demo success is defined as providing conclusive results, whether it proves the concept viable or not,  then such truth-via-prototype can be accomplished fairly easily.

Probability of Operational Success:  Given a Good rating due to the fact that once the robotic control of kites is achieved, this scheme has great potential to become an operational alternative to conventional wind power.

• 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
Message 2 of 15 , Apr 10, 2009

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
Message 3 of 15 , Apr 10, 2009

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

-----Original Message-----
From: brooksdesign
Sent: Apr 10, 2009 3:41 PM
To: AirborneWindEnergy@yahoogroups.com
Subject: Re: [AirborneWindEnergy] KiteGen

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```

```
________________________________________
PeoplePC Online
A better way to Internet
http://www.peoplepc.com```
• KiteGen Concept has grave flaws-   Carousels are essentially VAWTs (vertical axis wind tur.), always a performance hit. KiteGen flight pattern does not
Message 4 of 15 , Apr 11, 2009
 KiteGen Concept has grave flaws- Carousels are essentially VAWTs (vertical axis wind tur.), always a performance hit. KiteGen flight pattern does not maximize airspace. Capital Cost Intensity is super high for such a monster machine. Active control is bad enough without having to fly like iQuad team. Even if a KiteGen simply motors thru calm, robust landing/relaunching is essential around normal storm events. If just one string of kites crashes the whole shebang is down. One small kite problem may require stopping entire system. Kite crash becomes a dragline hazard as carousel flywheels along. All other kites can be wrapped by one crash. A common counter-rotating "gustnado" will tend to kill a KiteGen rather spectacularly a few times a year. Unlike a carousel, non "handed" geometries can counter negative (cyclonic) or postive (anticyclonic) helicity equally. But if they put the bobbing horseys back on, i'm for it... Re: circular/oval track schemes- These have VAWT sapping effect, running downwind & hauling upwind hurt, crosswind track best. Vehicles must take surge forces all along track & be able to relaunch/stop/pull-off/etc. from any position. Control complexity extreme. Track eats ground area.

• Dear Eaun, Again, if you seek KiteGen discussion with the Open-AWE movement, everything you write gets shared to the Cloud. Anyone who won t do that is not
Message 5 of 15 , Oct 11, 2016
Dear Eaun,

Again, if you seek KiteGen discussion with the Open-AWE movement, everything you write gets shared to the Cloud. Anyone who won't do that is not Open-AWE. Nobody in Open-AWE was trying to get KiteGen to do anything when you started promoting them. They had already paid off WOW, and settled, years ago. However, its a part of KiteGen's history for you to study, since you are in AWE now, as a marketer who should know his company. Be aware we do not think its OK to fool either small or large investors, by the same principle. You seemed to suggest otherwise.

KiteGen is seen as fooling investors, small or large, from the start. We do not know of a single patent-claim of KiteGen's that is a true inventive leap or blocking; its all a show. Massimo never became an aerospace guy. We almost had his technical ignorance laid bare on your blog when you shut the thread down on pretext. He was only ever a factory-automation guy. Italy has had far better talent, like KiteNRG, and KiteGen has failed to work with them, or anyone in the world, as equals. KiteGen has never even attended any of the six international AWE conferences.

If KiteGen were to open up its past test program, providing reliability statistics, showing it can do all-modes sessions, and so on, it would paint a bleak picture compared to its marketing fictions. Where is any public video of the big wing working? I mentioned Linux and HTML as model for Open-AWE, which goes back farther than KiteGen's secretive culture. If you are paid to think its wrongful to try and have AWE be an open-field, we understand that as opposed to the open view that its wrongful to be secret in AWE for pay. The ethics to us hinges on whether developing AWE solutions is more an urgent global need or a business opportunity. Its both, but the open-view is that the resource should belong to all, not just to creepy players like SABIC (until Saudi Arabia reforms socially).

Be careful to do your physics homework. For just one example, you guessed naively on your blog that AWE would best be done by Lift not Drag, in dismissing Rod Read's Rotary Kite Networks work, but the practical physics clearly dictate a mix of the two forces, and Rod's kites are crosswind parafoil-based (but just one of several AWES schemes with networked WECS). The sailing ships of the Golden Age of Sail only needed enough net lift to beat at a slight angle, but primarily circled the world with drag-power of "rag" wings. Hi L/D AWE wings with rigid composite structure are only superior until their first crash, and they need a lot longer pay-back period than pure "rag and string", like Ship Kites (I was recruited by KiteShip in 2006, whose gigantic ship-kites are L/D ~2, and have an MOU with SkySails whose fancier less-scalable kites are L/D ~5). Does the world need AWE as a "truck" or a "sports car"?

Good Luck to anyone betting on KiteGen's inbred golden-secrecy over unlimited viral transparency in developing AWE to its potential. Again, maybe you can help open them up, if you yourself embrace open-source tech development, which is not new at all, but more ancient than stealth venture-capitalism, and far bigger.

Sincerely,

dave santos

On Tuesday, October 11, 2016 4:14 AM, euan mearns <euan.mearns@...> wrote:

Dear Dave,

Correspondence yesterday evening came rather late and out of the blue for me.

I'm still trying to understand the nature of the WOW grievance. In email you have expressed this concept of Open-AWE which I'm afraid is rather alien to me. It is of course absolutely OK for you and your colleagues to pursue this ambition. But it is equally OK for other groups to choose to follow a different path. It is wrong, in my opinion, to try and coerce one group to join the other.

I have visited KiteGen 3 times so far this year. What I have seen is a lot of hard work combined with creativity and inventiveness. KiteGen have identified a path and followed it, patenting their inventions as they go. While you do not seem to have much respect for these patents, KiteGen have a different view and apply considerable resources to maintaining the patent inventory.

To the investor, the value of KiteGen is bound up in their patents, their people, their technology readiness level and their supply chain. This professional approach places them in a position where they can raise millions of € to fund the forward program.

At KiteGen there is a fairly serious language barrier and so I have been engaged to present KiteGen to the investor community. Before making an investment, any entity will conduct comprehensive financial and technical due diligence. Its quite simply not possible to fool them into making an investment on false premise. This type of diligence should of course precede any investment in a tech company where there are risks that are often difficult to quantify.

KiteGen are a very serious business and should in my opinion be allowed to go about that business unhindered by a group who seem to have donned some moral responsibility as the keepers of HAWP technology.

You (and all those on the copy list) should regard this email and all email correspondence between us as confidential. None of this should be forwarded to third parties or published on the internet.

Yours sincerely

Dr Euan Mearns

• http://kitegen.com/start/ http://kitegen.com/start/ Deep blog menu on right of page. Notice: 1. Site has its own English button. 2. Alternative for English of
Message 6 of 15 , Feb 5

http://kitegen.com/start/

Deep blog menu on right of page.

Notice:

1. Site has its own English button.

2. Alternative for English of shown pages linked: consider using robot translation via Bing or Google Translate or Microsoft translation.

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

• What a tiny ember of news about Rotterdam, that KiteGen made a final pitch round; but still no news on this blog-roll on why the Power Wing has never flown,
Message 7 of 15 , Feb 5
What a tiny ember of news about Rotterdam, that KiteGen made a final pitch round; but still no news on this blog-roll on why the Power Wing has never flown, over two years after the Wing was rolled out.

We are left guessing KiteGen did not win investor approval in the final round, since success would have been touted. Poor Euan, if he really was marketing KiteGen on pure speculation, to gild his retirement.

On Sunday, February 5, 2017 6:59 AM, "joefaust333@... [AirborneWindEnergy]" <AirborneWindEnergy@yahoogroups.com> wrote:

Deep blog menu on right of page.
Notice:
1. Site has its own English button.
2. Alternative for English of shown pages linked: consider using robot translation via Bing or Google Translate or Microsoft translation.
=====================================================

• Energy Is In The Air - The Event http://kitegen.com/2017/04/26/energy-is-in-the-air-levento/ By eugenio saraceno http://kitegen.com/author/eugenio-saraceno/ ,
Message 8 of 15 , Apr 26

## Energy Is In The Air - The Event

By eugenio saraceno , 26/04/2017

• Kitegen is upholding the ancient Italian tradition of panem et circenses , as we await the fate of the Power Wing, here seen mis-en-scene, if not en-vol.
Message 9 of 15 , Apr 26
Kitegen is upholding the ancient Italian tradition of "panem et circenses", as we await the fate of the Power Wing, here seen mis-en-scene, if not en-vol.

On Wednesday, April 26, 2017 11:06 AM, "joefaust333@... [AirborneWindEnergy]" <AirborneWindEnergy@yahoogroups.com> wrote:

## Energy Is In The Air - The Event

By eugenio saraceno , 26/04/2017

• Two years ago an article featured some detail photos of the big KiteGen wing: http://mashable.com/2015/06/07/kites-global-energy/#0FigWNZORgqr
Message 10 of 15 , Jun 14 10:27 AM
Two years ago an article featured some detail photos of the big KiteGen wing:

• Nice wing, but the challenge is how to fly it. An AWE scaling law we discovered is that a scaled-up kite needs scaled-up (dimensionless) wind This is most
Message 11 of 15 , Jun 14 11:34 AM
Nice wing, but the challenge is how to fly it. An AWE scaling law we discovered is that a scaled-up kite needs scaled-up (dimensionless) wind This is most critical with massive rigid, or in this case, semi-rigid wings, and less problematic for soft kites. The "stem" boom on the groundstation cupola cannot raise this wing very high, and Northern Italy does not have the best wind, so it will normally be a long wait to launch this wing from the stem. The problem is compounded by the need to get up over common morning surface inversion calm. This is the conjectured predicament to explain why KiteGen has no flying video after two years of waiting.

The wing could be tested with a rolling cradle and winch tow. The tether would be laid out on the ground with the wing downwind on its cradle, and the winch would haul up the kite into usable wind. Unfortunately, this wing will not do well in low most-probable-wind, and it does not look crashworthy. Like other major AWE ventures, if only KiteGen had concentrated on gathering the world into one team, to better solve the many hard problems, they would not be stuck at the limit of what a small closed team can do. Solving AWE at utility scale will require a far larger broader effort than any so far.

On ‎Wednesday‎, ‎June‎ ‎14‎, ‎2017‎ ‎12‎:‎27‎:‎46‎ ‎PM‎ ‎CDT, joefaust333@... [AirborneWindEnergy] <AirborneWindEnergy@yahoogroups.com> wrote:

Two years ago an article featured some detail photos of the big KiteGen wing:

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