Messages in AirborneWindEnergy group.                          AWES 24270 to 24320 Page 377 of 440.

Group: AirborneWindEnergy Message: 24270 From: Joe Faust Date: 12/2/2018
Subject: Kited air chamber mined for electricity generation

Group: AirborneWindEnergy Message: 24271 From: joe_f_90032 Date: 12/2/2018
Subject: Re: Visualizing Kite Lattice Waves (Networked Kites)

Group: AirborneWindEnergy Message: 24272 From: dave santos Date: 12/2/2018
Subject: Re: Kited air chamber mined for electricity generation

Group: AirborneWindEnergy Message: 24273 From: dave santos Date: 12/2/2018
Subject: Re: Visualizing Kite Lattice Waves (Networked Kites) [1 Attachment]

Group: AirborneWindEnergy Message: 24274 From: Joe Faust Date: 12/2/2018
Subject: Re: Kited air chamber mined for electricity generation

Group: AirborneWindEnergy Message: 24275 From: tallakt Date: 12/2/2018
Subject: Re: Kited air chamber mined for electricity generation

Group: AirborneWindEnergy Message: 24276 From: Joe Faust Date: 12/7/2018
Subject: TED Tethered Energy Drone :: energy kite system

Group: AirborneWindEnergy Message: 24277 From: dave santos Date: 12/7/2018
Subject: Gradual progress in academic AWE theorizing

Group: AirborneWindEnergy Message: 24278 From: dave santos Date: 12/7/2018
Subject: Re: Kited air chamber mined for electricity generation

Group: AirborneWindEnergy Message: 24279 From: dave santos Date: 12/7/2018
Subject: Vintage Gas-Bag Fueled Cars by KhrisD

Group: AirborneWindEnergy Message: 24280 From: dave santos Date: 12/7/2018
Subject: "MegaLung" Method (surface gas bag filling or drawing vacuum from up

Group: AirborneWindEnergy Message: 24281 From: dave santos Date: 12/7/2018
Subject: Cloud Control with Kites to cool the Earth

Group: AirborneWindEnergy Message: 24282 From: dave santos Date: 12/7/2018
Subject: Circular COTS Train as Giant Kite Arch Handling Aid (delivery, launc

Group: AirborneWindEnergy Message: 24283 From: Joe Faust Date: 12/7/2018
Subject: Re: "MegaLung" Method (surface gas bag filling or drawing vacuum fro

Group: AirborneWindEnergy Message: 24284 From: dave santos Date: 12/8/2018
Subject: Re: "MegaLung" Method (surface gas bag filling or drawing vacuum fro

Group: AirborneWindEnergy Message: 24285 From: dougselsam Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v

Group: AirborneWindEnergy Message: 24286 From: dave santos Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v

Group: AirborneWindEnergy Message: 24287 From: dave santos Date: 12/8/2018
Subject: Top Eight AWE Existence-Proofs

Group: AirborneWindEnergy Message: 24288 From: dave santos Date: 12/8/2018
Subject: Advancing Wubbo's SpiderMill Concept

Group: AirborneWindEnergy Message: 24289 From: dougselsam Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v

Group: AirborneWindEnergy Message: 24290 From: dave santos Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v

Group: AirborneWindEnergy Message: 24291 From: benhaiemp Date: 12/8/2018
Subject: Available power in the wind

Group: AirborneWindEnergy Message: 24292 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24293 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Available power in the wind

Group: AirborneWindEnergy Message: 24294 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24295 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24296 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24297 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24298 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24299 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24300 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24301 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind [1 Attachment]

Group: AirborneWindEnergy Message: 24302 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24303 From: dave santos Date: 12/8/2018
Subject: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", and p

Group: AirborneWindEnergy Message: 24304 From: dave santos Date: 12/8/2018
Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a

Group: AirborneWindEnergy Message: 24305 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a

Group: AirborneWindEnergy Message: 24306 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a

Group: AirborneWindEnergy Message: 24307 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a

Group: AirborneWindEnergy Message: 24308 From: tallakt Date: 12/9/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24310 From: benhaiemp Date: 12/9/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24311 From: benhaiemp Date: 12/9/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24312 From: dave santos Date: 12/9/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24313 From: Pierre BENHAIEM Date: 12/9/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24314 From: dave santos Date: 12/9/2018
Subject: Review: Power-to-Weight as top AWES Figure-of-Merit

Group: AirborneWindEnergy Message: 24315 From: dave santos Date: 12/9/2018
Subject: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" case)

Group: AirborneWindEnergy Message: 24316 From: Pierre BENHAIEM Date: 12/9/2018
Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c

Group: AirborneWindEnergy Message: 24317 From: tallakt Date: 12/9/2018
Subject: Re: Available power in the wind

Group: AirborneWindEnergy Message: 24318 From: Peter Sharp Date: 12/9/2018
Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c

Group: AirborneWindEnergy Message: 24319 From: dave santos Date: 12/9/2018
Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c

Group: AirborneWindEnergy Message: 24320 From: benhaiemp Date: 12/9/2018
Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c




Group: AirborneWindEnergy Message: 24270 From: Joe Faust Date: 12/2/2018
Subject: Kited air chamber mined for electricity generation
 Drive kited wing up in altitude. Have a chamber of air in that wing; let there be a hole in that chamber.  Air in that chamber would tend to escape when the wing rises.  That escaping air could drive an electric generator.  If the chamber is rigid, then when letting the wing drop in altitude, there will be a moving of air back into the chamber; let that movement of air drive an electric generator. So, as the wing rises or descends, electricity may be generated by mining the expansion and compression of air; mine the in and out flows of the chamber.  Such AWES method has not been noted in my view. Let me know if prior art is on record.   
    KiteLab, Los Angeles
Group: AirborneWindEnergy Message: 24271 From: joe_f_90032 Date: 12/2/2018
Subject: Re: Visualizing Kite Lattice Waves (Networked Kites)
The image arrived as a .png   not GIF. 
might be your sourced file. 
Using two copies of Chrome, I am dragging image GIF into the compose space while operating signed in at the form: 


Group: AirborneWindEnergy Message: 24272 From: dave santos Date: 12/2/2018
Subject: Re: Kited air chamber mined for electricity generation
This concept depends on a fabric bag as a (tensile) pressure vessel, since no large rigid vessel can be made very light. There is a functional analogy with our past discussions of airbags underwater as an energy conversion/storage device. Another comparison can be made with Fuller-Bolonkin domes in airship mode, where enclosed volume acts both as habitat and pressure vessel. Its a feasible source of aux power, if not an economic bulk power basis. The practical limits are in part the operational limits of large inflated structures to resist storm forces and inherent low velocity. In the most abstract view, any wing captures a pressure field whose energy increases with altitude. There is a flygen element in the concept, with associated pros (like nomadic mobility) and cons (flygen mass, frontal drag, etc.). An advantage is that high-velocity PTO flow can be developed from a large diffuse pressure field, minimizing flygen mass. A variant concept might be to tap the elastic energy of the volume with internal or external PTO taglines. Thermal gradient and solar gain may be large inputs to the energy harvest.



 

 Drive kited wing up in altitude. Have a chamber of air in that wing; let there be a hole in that chamber.  Air in that chamber would tend to escape when the wing rises.  That escaping air could drive an electric generator.  If the chamber is rigid, then when letting the wing drop in altitude, there will be a moving of air back into the chamber; let that movement of air drive an electric generator. So, as the wing rises or descends, electricity may be generated by mining the expansion and compression of air; mine the in and out flows of the chamber.  Such AWES method has not been noted in my view. Let me know if prior art is on record.   
    KiteLab, Los Angeles
Group: AirborneWindEnergy Message: 24273 From: dave santos Date: 12/2/2018
Subject: Re: Visualizing Kite Lattice Waves (Networked Kites) [1 Attachment]
Return copy sent back a JPG (not an animated GIF), but the GIF JoeF resent was waving nicely. 

That -excite- material science source software is inherently suited to model kite lattice waves underscores close analogy between micro and mega scale dynamics. The three -excite- demo animations really do help visualize AWES lattice design options. Sure glad Open-AWE does not have to cough up its own code.*

There seems to be an aerodynamic flocking law to apply, after Zhang Lab's findings of lowered drag not just for trailing units, but also for leading units, meaning coherent elastic waves can passively redistribute gradient forces harmonically. 

====
* as happy not to pay the ~300M USD its taking to vet high-complexity AWES architectures







 
[Attachment(s) from dave santos included below]

{This is a test of upgrading to a better mailer and new machine; to see if the animated GIF pasted below moves and the hot link works. Thanks for putting up with primitive emails under the previous set-up.}

Visualizing Kite Lattice Waves (Networked Kites)

Pumping Kite Networks are inspired by a crystal lattice wave analogy, and the same mathematics applies. In the animated GIF below, each atom in the crystal can be taken as a kite element. As seen from above, the wave motions are to be considered as crosswind motion, and the black background as a PTO groundgen field. Not shown is a pilot lifter layer, which might or might not be a standard layer. Its presumed that reverse-pumped waves can maintain flight of the lattice in calm.

There are higher-order complexities to account for in a better model, like wind gradient and shadowing effects, but any expert in kites can see the feasibility of the general idea, as a potential GW rated WECS.

Hope this helps folks understand what may be the ultimate AWE and aerotecture basis; Networked Kites-


Inline image



Group: AirborneWindEnergy Message: 24274 From: Joe Faust Date: 12/2/2018
Subject: Re: Kited air chamber mined for electricity generation
DaveS: "A variant concept might be to tap the elastic energy of the volume with internal or external PTO taglines."
Nice!    One may look to history of flight instruments for near embodiments of aforementioned and the just noted variant. 
Group: AirborneWindEnergy Message: 24275 From: tallakt Date: 12/2/2018
Subject: Re: Kited air chamber mined for electricity generation
It has been done subsea. Even there it’s marginal, but feel free to explore :)
Group: AirborneWindEnergy Message: 24276 From: Joe Faust Date: 12/7/2018
Subject: TED Tethered Energy Drone :: energy kite system
eWind coining "TED"  for tethered energy drone.
for its energy kite system. 
Pumping system is TED. 
==============================
Group: AirborneWindEnergy Message: 24277 From: dave santos Date: 12/7/2018
Subject: Gradual progress in academic AWE theorizing
Linked below is [Costello et al, 2015], which is being cited in Quartz, a cosmopolitan economics website whose AWE article is linked at bottom. Given the new attention, this post reviews [Costello et al, 2015] as a characteristic snapshot of academic AWE theory five years ago.

[Costello et al, 2015] once again finds [Loyd, 1980] to be the formal analytic beginning of modern AWE theory. The 2015 paper adds a standard aeronautical gravity-based factor, power-to-weight, as an extension to [Loyd, 1980], which disregarded gravity in its initial focus on pure power factor. Power-to-weight adds considerable realism to AWE modelling, since AWES architectures vary so much in the parasitic energetic cost to maintain mass aloft. SkySails' shipkite case shines by superior power-to-weight to Ampyx's kiteplane case.

Other critical factors remain outside of the evolving academic paradigm presented by [Costello et al, 2015]. No mention is made of multi anchor geometric topologies with direct crosswind power extraction (Payne, Goldstein, KiteLab, etc.). High altitude harvesting is discounted by overlooking traditional kite train capability to tap lift/power in stages all the way up. No mention is made of kite networks, barely considered in AWE up to that time.

Such is the slow majestic arc of cautious academic understanding. New AWE papers in progress will make incremental advances in formal peer-reviewed understanding. The AWES Forum role is early identification of AWE domain knowledge, for eventual validation by academia and ultimate empirical success. The process of working out AWES engineering science continues...



Group: AirborneWindEnergy Message: 24278 From: dave santos Date: 12/7/2018
Subject: Re: Kited air chamber mined for electricity generation
Its agreed with Tallak that Gas Bags alone seems marginal as a WECS basis, compared to direct energy extraction, but its the potential synergistic advantages of hybrid energy/material-processing uses that most attract us. KiteLab has done cool things with ram-air bags, like lifting proportionally large (sand) masses with a filling ram-air bag.

One such synergistic Gas Bag direction is the possibility to process bulk gases in giant bags. All sorts of ideas come to mind; pollutants can be removed, chemical synthesis supported, and so on. The energy required to support such processes could come from bag dynamics in wind, or even by exploding flammable H2 gas puffs in the center volume. Think of a Gas Bag as a giant piston mechanism.

Our theoretic model of a wing is as a partial enclosure or wall separating two fields of differing pressure. One can see wing or bag as having enclosure-factors on the same continuum. We explore this continuum as a whole design space, expecting both common and particular engineering advantages. We can predict that large bags can be deflated and stored to avoid storm loads.

The biomimetic model here is animal lung function, with oxidation as the energy-conversion basis. What might mega-scale lungs someday do? We have hardly imagined the possibilities.

Here is a practical advance to known Gas Bag art- Aerostat/blimp design has long depended on ballonet use, the internal partitioning of gas bags. Internal networks of lazy-jack rigging can comprise related structure, with a natural PTO capability. Internal load lines will not tend to chafe an envelope as external surface tensioners would. Open-AWE_IP-Cloud






 

It has been done subsea. Even there it’s marginal, but feel free to explore :)

Group: AirborneWindEnergy Message: 24279 From: dave santos Date: 12/7/2018
Subject: Vintage Gas-Bag Fueled Cars by KhrisD
Extending study of giant gas bag tech from well known Airship practice to almost forgotten Gas Bag Cars. Lesson: Even quirky methods can have their day; study them for fun and possible reuse-



Thanks again to our friend, KhrisD, for his usual wonderful Low Tech Magazine reporting.
Group: AirborneWindEnergy Message: 24280 From: dave santos Date: 12/7/2018
Subject: "MegaLung" Method (surface gas bag filling or drawing vacuum from up
Take "MegaLung" to mean here a large gas bag whose operation is periodic oscillation in "inhale-exhale" cycles. What methods and applications might apply? We can use kite power to replicate lung muscle, to take us beyond a gas bag ram-air assumption.

Surface inversions with still air are common, especially during early morning hours. Meanwhile, prevailing wind continues above, even quite enhanced, as an LLJ (low-level-jet) layer. A surface ram-air megalung would not work at all in a surface inversion, and comparatively poorly in an ordinary wind gradient. Surface ram-air is relatively weak, and a long ram-air cowl vent to upper wind is rather inefficient.

A better method would be high-flying power kites tethered to the surface megalung gas bag. By pulling outward on the bag directly and powerfully, the megalung would inflate at high efficiency. A HAWT at the intake could produce power. Its an open question if such simple methods have a future. 

If nothing else, here is a quite curious potential application of biological lung mechanics. Another large similarity case-base is Bellows technology (and pumps, broadly). Many variations are possible. One might even draw a vacuum in bag, by means of kites. Open-AWE_IP-Cloud
Group: AirborneWindEnergy Message: 24281 From: dave santos Date: 12/7/2018
Subject: Cloud Control with Kites to cool the Earth
As long discussed, kites can in principle modify weather. We understand how night clouds act as a blanket, trapping heat, and day clouds as a reflector, radiating heat to space. Therefore, kites could harvest clouds at night, for fresh water, and make clouds by day, with sea water, and thus act to cool the planet. This would be an amplified effect compared to direct kite shade/reflection, which could also play its part. AWE itself might be a hybrid output, for direct revenue.

The kite cloud control methods we have long explored have both local short-term effects and general long-term effects. It should be possible to provide extra cooling and more or less water in places most in need, while in the long term cooling the whole planet. An inherent advantage of cloud control kite methods is that they can be deployed in a thin line crosswind to process huge volumes of atmospheric flow.  This methodology to mitigate climate change might work rather quickly, and all the kites emerge from one super-factory in just a few years.

As the world mobilizes to fight excessive atmospheric heating, advanced research into kite cloud control concepts should be supported, like AirHes's ideas for harvesting clouds; or KiteLab's idea of flying kites right at the shifting dew-point altitude, to make cloud wakes (con-trails).
Group: AirborneWindEnergy Message: 24282 From: dave santos Date: 12/7/2018
Subject: Circular COTS Train as Giant Kite Arch Handling Aid (delivery, launc
kFarm validated that large kite arches are not too hard to rotate in flight (kPower's 300m2 Mothra), by moving the anchor points by either simple belay or vehicle. Handling giant kites on the ground is far slower and more delicate, since the thin fabric must not be damaged by massive dragging. Set up can be slow, and wind direction hard to match.

A COTS train on a circular track matched to a kite anchor circle can solve much of the giant kite arch ground handling problem. A giant arch kite could be loaded on a train as it moves thru a factory loft, and then roll to whatever sector of anchor circle matches wind direction. Launch could be directly from a train, and landing directly to a train, by known methods.

kPower's evolving kite arch methods are Open-AWE_IP-Cloud.


Group: AirborneWindEnergy Message: 24283 From: Joe Faust Date: 12/7/2018
Subject: Re: "MegaLung" Method (surface gas bag filling or drawing vacuum fro


Group: AirborneWindEnergy Message: 24284 From: dave santos Date: 12/8/2018
Subject: Re: "MegaLung" Method (surface gas bag filling or drawing vacuum fro
Nice concept graphic, JoeF. How did we so long overlook "pulling a vacuum" by kite power, a power that loves to pull?

It suggests what could happen if the surface kite-pulled vacuum chamber were connected by a Venturi profile hose to an upper air level. Cold upper air would be drawn down, hopefully losing even more temperature, to create a super-cooled volume of air at the surface? Ordinarily, a volume of cold air dragged down into higher pressure heats up considerably, by heat of compression; on the other hand, air expanding into a relative vacuum cools further. 

Compare this with our prior ideas to raise water to freeze into ice to bring down for cooling; pulling a vacuum may be a more direct scalable process. This would be a second kind of kite-based novel mass refrigeration and air conditioning technology. The open problem is how to best design a megahose that itself needs to be kept pulled open by kite power...



 



On Fri, Dec 7, 2018 at 12:00 PM dave santos santos137@yahoo.com [AirborneWindEnergy] <AirborneWindEnergy@yahoogroups.com
Group: AirborneWindEnergy Message: 24285 From: dougselsam Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v
This is exactly what I'm talking about.  I remember the (supposed, wannabe) "other demos" at HAWPcon09.  Against a backdrop of my working system capable of (gasp!) actually generating power, that (gasp!) ran mostly unattended for (gasp!) two days, which got the whole conference on the front page of newspapers, a few people brought out what I remember as a couple of irrelevant foam wings on a string, pulled around with a stick at a height of maybe 10 feet, something like that.  Goofy nothingness. 

That was ten years ago - if they were "demos", where are the resulting systems today?  "AWE" "Demos" incapable of generating any power.  "Demos" so forgettable that nobody has ever mentioned them besides you.  "Demos that made me feel sorry for the people "flying" them, as in "REALLY?  That's all you got?  You even brought that here as a demo of anything?   A demo of what exactly, that you can't even get something to fly without dragging it around using overhead with a stick?"  Those "demos" were pathetic, if they can seriously even be called "demos" at all, which I do not think they can.  The only thing those less-than-toys "demonstrated" was the people playing with them were nowhere with regard to AWE, with nothing promising on the horizon.    Why don't you explain these "demos' to "the rest of the class", and show us some photos, so people can witness the advanced state of your aerospace AWE R & D program at that time?

Here's what I DO remember:  Endless attacks, and yes, unfair attacks, from you.  Starting with accusing me of "wasting helium" because I used two bottles of it to possibly change the world, whereas literally millions of times as much is "wasted" on party balloons at 99-cent stores etc. across the world, probably every day.  Every time I pick up another expired party balloon on my properties, I think of your irrational accusation that the main thing you got out of my demo at HAWPcon09 was that I was "wasting helium."

Well I HAD to use helium, because while most newbies don't understand that you need wind for a wind energy system to work, they want to see one work anyway, even if the amount of wind is low.  Due to lack of wind, a kite would not have worked.  So I was forced to stick with balloons even though a kite would have worked better in actual wind, conferences and video-shoots can't be scheduled with sufficient advance time to allow airline flights to be reserved etc., around daily local weather, and unless you are in a known high-wind area, which that conference was not, the chances of sufficient wind for a WECS are slim to none.

Since then we've seen an unending tirade of insults about any aspect of SuperTurbine that pops into your head, such as torque being a problem compared to pulling ropes, even though our entire civilization is powered by torque, while pulling rope drives fell out of favor back in the early days of the steam engine.  Or I'm attacked on the basis that "it can't scale" whereas the same thing has always been said about every wind energy collection system, but somehow, they do.  A typical automotive driveshaft can carry a MegaWatt.  But that doesn't slow you down.

If I convey my alarm that people keep talking about "laddermill" while a hundred grad students and interns led by a supposed "astronaut" together can't even build a popsicle-stick-level demo of the actual laddermill concept, after years of empty talk, it is ME who is called labels like "dire" or "negative" even though all I am doing is describing the lack of action of others who keep saying they are developing it.  To me, the people who announce projects that they never actually follow through on, are the negative ones.  To call the people merely witnessing such a lack of follow-through, derogatory names is just typical "shoot-the-messenger" behavior.  It's like saying "close your eyes - you did not just see that and you should never mention it to anyone, ever!  Nobody is ever allowed to ask what happened to any AWE project, ever, OK?"  Uh, yeah, OK, sure.

If, after ten previous years I have developed a "sense of smell" that allows me to categorically provide the accurate information that one after another stated project to "power X hundred homes" is NOT in fact taking place, I'm only further denigrated, as though the people making the false statements are in the right, while I am wrong to (try to) call them out.

Let's look at it logically: A company announces how many "engineers" it's hiring, administrators, fabricators, power electronics people, etc., etc., etc.  They have university and industry pedigrees, they are paid good salaries, there are so many they need an HR department just to keep track of them all, and so much office space it's seen necessary to announce just renting it.  There are CEO's, project managers, accountants and of course interns and grad students, ready to line up and smile for their smartphones. 

So you have a huge amount of highly-educated "talent", complete with "adults in the room" who should have the ability to forecast whether a project is on track to meet certain milestones by a given date.  But the puzzling question keeps emerging:  If this much "high-end talent" is being applied effectively, why do the stated outcomes never materialize as advertised?  Why is no information ever available when the announced "show-time" rolls around?  Why is it then, not even possible to find out what happened to the projects?

How is it possible, over and over again, for that many supposedly-knowledgeable people, with all those credentials,and all that money, to make the same basic promise over and over, and be that wrong, every single time?  How can they say they will power x hundred homes, then power exactly zero homes?  What good is all that education and industry experience?  How can that many project managers be that consistently inaccurate in their projections?  Do they actually have no idea or real understanding of what they're trying to do?  I mean, normally that much talent would be able to turn out at least something, even if it was less than projected.

It would be easy to understand, for example, a project announcing it was only able to produce about half the power it had anticipated, with reasons given for the discrepancy, and possible remedies suggested to improve the results next time.  Maybe they run it for a year, then announce a cessation of operation and a rebuild, based on what was learned.  That is what one might expect from adults with basic integrity.

On the other hand, imagine an NFL team claiming they'll win the Superbowl, then just not showing up at "showtime"...  Imagine a highly-publicized project to build a bridge, with opening day announced a year ahead of time, with every subsequent detail publicly specified: the budget, the number and talents of people hired, tasks allocated to subcontractors, when various components are ordered, when they arrive, etc., then on the opening day (showtime), when the mayor was supposed to show up for the ribbon-cutting ceremony, suddenly the entire project simply goes dark, and you never hear anything from them again, until maybe years later, the same bridge project is announced again, and people fall for it again, as though they never said this before.  Could this really even happen?

Look at Elon Musk for example.  People wonder whether the company will meet its stated goals by the announced times, and whether it will thus survive as a business entity, but nobody has to ask whether he ever produced a working car in the first place, or why he said he would produce thousands, then just disappeared, with no further news available.  If that happened he'd probably be arrested or severely sanctioned in some way.  The SEC would have a cow.  Investors would be filing lawsuits.

These days I'm silenced for even ASKING the status of any of these highly-publicized AWE or underwater kite projects, as "showtime" shows up.  Fantasy only - no facts allowed.  The promoters are allowed to take in millions of dollars to SAY they WILL power X number of homes by date Y at location Z using technology Q, and yet I am castigated for then even asking the question of what is actually happening when date Y rolls around.

Amazing.  I am "bad".  They are "good", right?  Yeah sure, Joe says "I know where you're going with that" when, after seeing this happen over and over, I ask peoples' opinion on whether the underwater-kite project designed by jet turbine engineers, backed by large organizations, will ever truly enjoy a successful rollout.  NO JOE, the point is I have a pretty good idea of where THEY are going with their likely-false predictive statements - it would be typical if they are raising millions of dollars and not doing what they say they will do.  Period.  Odds are, at this point, they're playing "fake-it-til-you-make-it", but without the "make-it" part.  These companies that don't follow through on their high-publicity projects are most likely letting you down, me down, and everyone who wastes time being interested down.  Let alone people who are invested.  How many times are we willing to subject ourselves this level of disappointment, before we speak up?  There's a name for what these companies are doing.

Apparently nobody else realizes what's going on except me.(?)  A hundred sources repeat the false statements, and you have little old me standing in the middle of an empty field asking what the result is, being ignored and called names for even asking, by people with their fingers in their ears, saying "la la la I can't hear you", while the projects suddenly do nothing, say nothing, and the focus then shifts to the next "future" "project" in quotes only, since, well, should we expect every next announcement will turn into a real project that gets completed?.  At some point, we need to ask ourselves: How gullible are we anyway?

Since then, the attacks from daveS have never ceased.  It's as though you're in a fantasy-world of all-talk, all the time, where any progress is seen as a threat to your own lack of results, while misguided programs unlikely to bear fruit are worshipped in a religious frenzy, since deep-down you realize as long as nobody has any real success, you can posture as a "contender", even while not having developed any significantly-power-producing prototype at all, the whole time, let alone 10 years ago at the first conference..


---In AirborneWindEnergy@yahoogroups.com, <santos137@...
Sorry if Doug feels so unfairly treated. He did get good coverage by SF press.
Group: AirborneWindEnergy Message: 24286 From: dave santos Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v
Doug was welcome to rely on helium for his demo. I worked with helium LTA UAS for a decade. My critique of helium dependence as an AWE basis is general; that widespread dependence on helium for AWE would be costly, wasteful, and quite unnecessary.

I am sorry Doug feels unfairly attacked by technical critique of the ST architecture. His best bet is to succeed in his AWE R&D, in whatever workable form his solutions may take.



 

This is exactly what I'm talking about.  I remember the (supposed, wannabe) "other demos" at HAWPcon09.  Against a backdrop of my working system capable of (gasp!) actually generating power, that (gasp!) ran mostly unattended for (gasp!) two days, which got the whole conference on the front page of newspapers, a few people brought out what I remember as a couple of irrelevant foam wings on a string, pulled around with a stick at a height of maybe 10 feet, something like that.  Goofy nothingness. 

That was ten years ago - if they were "demos", where are the resulting systems today?  "AWE" "Demos" incapable of generating any power.  "Demos" so forgettable that nobody has ever mentioned them besides you.  "Demos that made me feel sorry for the people "flying" them, as in "REALLY?  That's all you got?  You even brought that here as a demo of anything?   A demo of what exactly, that you can't even get something to fly without dragging it around using overhead with a stick?"  Those "demos" were pathetic, if they can seriously even be called "demos" at all, which I do not think they can.  The only thing those less-than-toys "demonstrated" was the people playing with them were nowhere with regard to AWE, with nothing promising on the horizon.    Why don't you explain these "demos' to "the rest of the class", and show us some photos, so people can witness the advanced state of your aerospace AWE R & D program at that time?

Here's what I DO remember:  Endless attacks, and yes, unfair attacks, from you.  Starting with accusing me of "wasting helium" because I used two bottles of it to possibly change the world, whereas literally millions of times as much is "wasted" on party balloons at 99-cent stores etc. across the world, probably every day.  Every time I pick up another expired party balloon on my properties, I think of your irrational accusation that the main thing you got out of my demo at HAWPcon09 was that I was "wasting helium."

Well I HAD to use helium, because while most newbies don't understand that you need wind for a wind energy system to work, they want to see one work anyway, even if the amount of wind is low.  Due to lack of wind, a kite would not have worked.  So I was forced to stick with balloons even though a kite would have worked better in actual wind, conferences and video-shoots can't be scheduled with sufficient advance time to allow airline flights to be reserved etc., around daily local weather, and unless you are in a known high-wind area, which that conference was not, the chances of sufficient wind for a WECS are slim to none.

Since then we've seen an unending tirade of insults about any aspect of SuperTurbine that pops into your head, such as torque being a problem compared to pulling ropes, even though our entire civilization is powered by torque, while pulling rope drives fell out of favor back in the early days of the steam engine.  Or I'm attacked on the basis that "it can't scale" whereas the same thing has always been said about every wind energy collection system, but somehow, they do.  A typical automotive driveshaft can carry a MegaWatt.  But that doesn't slow you down.

If I convey my alarm that people keep talking about "laddermill" while a hundred grad students and interns led by a supposed "astronaut" together can't even build a popsicle-stick-level demo of the actual laddermill concept, after years of empty talk, it is ME who is called labels like "dire" or "negative" even though all I am doing is describing the lack of action of others who keep saying they are developing it.  To me, the people who announce projects that they never actually follow through on, are the negative ones.  To call the people merely witnessing such a lack of follow-through, derogatory names is just typical "shoot-the-messenger" behavior.  It's like saying "close your eyes - you did not just see that and you should never mention it to anyone, ever!  Nobody is ever allowed to ask what happened to any AWE project, ever, OK?"  Uh, yeah, OK, sure.

If, after ten previous years I have developed a "sense of smell" that allows me to categorically provide the accurate information that one after another stated project to "power X hundred homes" is NOT in fact taking place, I'm only further denigrated, as though the people making the false statements are in the right, while I am wrong to (try to) call them out.

Let's look at it logically: A company announces how many "engineers" it's hiring, administrators, fabricators, power electronics people, etc., etc., etc.  They have university and industry pedigrees, they are paid good salaries, there are so many they need an HR department just to keep track of them all, and so much office space it's seen necessary to announce just renting it.  There are CEO's, project managers, accountants and of course interns and grad students, ready to line up and smile for their smartphones. 

So you have a huge amount of highly-educated "talent", complete with "adults in the room" who should have the ability to forecast whether a project is on track to meet certain milestones by a given date.  But the puzzling question keeps emerging:  If this much "high-end talent" is being applied effectively, why do the stated outcomes never materialize as advertised?  Why is no information ever available when the announced "show-time" rolls around?  Why is it then, not even possible to find out what happened to the projects?

How is it possible, over and over again, for that many supposedly-knowledgeable people, with all those credentials,and all that money, to make the same basic promise over and over, and be that wrong, every single time?  How can they say they will power x hundred homes, then power exactly zero homes?  What good is all that education and industry experience?  How can that many project managers be that consistently inaccurate in their projections?  Do they actually have no idea or real understanding of what they're trying to do?  I mean, normally that much talent would be able to turn out at least something, even if it was less than projected.

It would be easy to understand, for example, a project announcing it was only able to produce about half the power it had anticipated, with reasons given for the discrepancy, and possible remedies suggested to improve the results next time.  Maybe they run it for a year, then announce a cessation of operation and a rebuild, based on what was learned.  That is what one might expect from adults with basic integrity.

On the other hand, imagine an NFL team claiming they'll win the Superbowl, then just not showing up at "showtime"...  Imagine a highly-publicized project to build a bridge, with opening day announced a year ahead of time, with every subsequent detail publicly specified: the budget, the number and talents of people hired, tasks allocated to subcontractors, when various components are ordered, when they arrive, etc., then on the opening day (showtime), when the mayor was supposed to show up for the ribbon-cutting ceremony, suddenly the entire project simply goes dark, and you never hear anything from them again, until maybe years later, the same bridge project is announced again, and people fall for it again, as though they never said this before.  Could this really even happen?

Look at Elon Musk for example.  People wonder whether the company will meet its stated goals by the announced times, and whether it will thus survive as a business entity, but nobody has to ask whether he ever produced a working car in the first place, or why he said he would produce thousands, then just disappeared, with no further news available.  If that happened he'd probably be arrested or severely sanctioned in some way.  The SEC would have a cow.  Investors would be filing lawsuits.

These days I'm silenced for even ASKING the status of any of these highly-publicized AWE or underwater kite projects, as "showtime" shows up.  Fantasy only - no facts allowed.  The promoters are allowed to take in millions of dollars to SAY they WILL power X number of homes by date Y at location Z using technology Q, and yet I am castigated for then even asking the question of what is actually happening when date Y rolls around.

Amazing.  I am "bad".  They are "good", right?  Yeah sure, Joe says "I know where you're going with that" when, after seeing this happen over and over, I ask peoples' opinion on whether the underwater-kite project designed by jet turbine engineers, backed by large organizations, will ever truly enjoy a successful rollout.  NO JOE, the point is I have a pretty good idea of where THEY are going with their likely-false predictive statements - it would be typical if they are raising millions of dollars and not doing what they say they will do.  Period.  Odds are, at this point, they're playing "fake-it-til-you-make-it", but without the "make-it" part.  These companies that don't follow through on their high-publicity projects are most likely letting you down, me down, and everyone who wastes time being interested down.  Let alone people who are invested.  How many times are we willing to subject ourselves this level of disappointment, before we speak up?  There's a name for what these companies are doing.

Apparently nobody else realizes what's going on except me.(?)  A hundred sources repeat the false statements, and you have little old me standing in the middle of an empty field asking what the result is, being ignored and called names for even asking, by people with their fingers in their ears, saying "la la la I can't hear you", while the projects suddenly do nothing, say nothing, and the focus then shifts to the next "future" "project" in quotes only, since, well, should we expect every next announcement will turn into a real project that gets completed?.  At some point, we need to ask ourselves: How gullible are we anyway?

Since then, the attacks from daveS have never ceased.  It's as though you're in a fantasy-world of all-talk, all the time, where any progress is seen as a threat to your own lack of results, while misguided programs unlikely to bear fruit are worshipped in a religious frenzy, since deep-down you realize as long as nobody has any real success, you can posture as a "contender", even while not having developed any significantly-power-producing prototype at all, the whole time, let alone 10 years ago at the first conference..


---In AirborneWindEnergy@yahoogroups.com, <santos137@...
Sorry if Doug feels so unfairly treated. He did get good coverage by SF press.
Group: AirborneWindEnergy Message: 24287 From: dave santos Date: 12/8/2018
Subject: Top Eight AWE Existence-Proofs
1) 5% of jet transport fuel is conserved by flight planning to maximize tailwinds

2) Kitesailing is an ancient Polynesian tradition. Modern kites have pulled ships across oceans.

3) Watersking by fossil-fueled ski-boats has been displaced by kiteboarding.

4) Soaring sports are inherently AWE driven.

5) Virtually all AWES R&D teams have generated power, several
Group: AirborneWindEnergy Message: 24288 From: dave santos Date: 12/8/2018
Subject: Advancing Wubbo's SpiderMill Concept
Shortly before his tragic untimely death, Wubbo Ockels made his deepest AWES architectural meditation, the SpiderMill concept, surpassing all his prior concepts. He presented SpiderMill with great excitement in his keynote at AWEC2010, in Leuven. No written records have been made public. Fortunately, Wubbo's conference presentation was quite simple and crystal clear.

The Spidermill is a branching kite train (traditional "Eddy Train") with the added capability for every kite, in synchrony, to pull the main tether crosswind into a zig-zag shape, then relax, causing pumping tension cycles at the surface. Normally, an Eddy Train's kites swim in uncoordinated doodles, with more-or-less constant pull overall. Wubbo's astronaut-professor race-horse brilliance was to see how coherent Eddy Train motion turns this quaint Victorian novelty into a futuristic power-plant. Behold, the SpiderMill; a Second-Coming of Dutch Wind Genius.

Since Wubbo made this great inventive leap, we have reported several advances on the AWES Forum. The SpiderMill embodies tri-tether nodes that we deeply studied as variable power transmissions, a simple Rigger's Triangle mechanical advantage with ordinary string. We saw SpiderMills can be lined up crosswind in parallel to form a vast power mesh. A pesky missing detail; how to best to support long-stroke vertical motion while keeping kites at their working altitudes.

The solution turns out to be an extension of the simple fixed tri-tether. A pulley/block on one tether runs along a line whose ends are the other two tethers of the triad. For the improved SpiderMill, as the vertical line is pumped, each kite is connected by a pulley pendant-tether, so the pumped line runs free. There are of course a few more engineering details to resolve; like active-control and/or a passive-control interconnect network to keep the kites in synchrony in their scopes. 

AWES Forum SpiderMill advances are Open-AWE_IP-Cloud.
Group: AirborneWindEnergy Message: 24289 From: dougselsam Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v
I agree that helium has its problems.
But for demonstrating the ST at that conference with so little wind, it was the only way I had available.
Even with its limitations, nobody can categorically rule out helium, hydrogen, etc. as potentially useful.
Group: AirborneWindEnergy Message: 24290 From: dave santos Date: 12/8/2018
Subject: Re: Reply to Doug's post// Re: [AWES] Re: W = m * g (NASA syntax) v
The aeronautical best-practice suggestion to Doug made at HAWPcon2009 was for a streamlined aerostat (microblimp) envelope with good gas retention, rather than the weather balloons repeatedly used, which leak away gas quickly. If using helium is a moral fault, I have used my share. Doug could also have used a pilot-lifter kite to lift his WECS, like many do.

The Sky Serpent was as worthy an effort as the other pioneering prototypes in the early mix. Ten years later, AWE really is advancing, and what happens next is what counts most. Lets hope Doug has continued progress in the air.



 

I agree that helium has its problems.
But for demonstrating the ST at that conference with so little wind, it was the only way I had available.
Even with its limitations, nobody can categorically rule out helium, hydrogen, etc. as potentially useful.
Group: AirborneWindEnergy Message: 24291 From: benhaiemp Date: 12/8/2018
Subject: Available power in the wind

The Betz limit applied to Airborne Wind Energy 

 

states:

 

"•

AWE drag power systems can harvest up to 16/27 of the power available in the wind.

AWE lift power systems can harvest up to 4/27 of the power available in the wind.

AWE lift power systems require aerodynamic drag in order to harvest useful power."

"One of our contributions is to suggest that the Betz limit of 16/27≈59% should in fact hold true for any device that harvests power through drag or torque in a horizontal-axis rotational motion perpendicular to the wind field, which is not only the case of conventional wind turbines but also of Loyd's drag power Airborne Wind Energy (AWE) systems."

 

AWE drag power systems are also called "flygens" (Makani), and the same statement (...16/27..) can be made for rotating AWE systems like Daisy or Rotating Reel or SuperTurbine (tm).

AWE lift power systems are pumping mode, also called yoyo or reel-out/in systems.

Is the torque winning over the traction?”

Group: AirborneWindEnergy Message: 24292 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind
To explain such unrealistic numbers, this paper seems to disregard power-to-weight as the most predictive number in AWE performance. Can anyone behind the paywall confirm this?

Nothing in the real world of tested AWE supports the numbers given. Match of test data to predicted numbers is the required validation of prediction. Betz is also a poor lens to judge AWE, compared to LCOE or power-to-weight. 



 

The Betz limit applied to Airborne Wind Energy 

 

states:

 

"•

AWE drag power systems can harvest up to 16/27 of the power available in the wind.

AWE lift power systems can harvest up to 4/27 of the power available in the wind.

AWE lift power systems require aerodynamic drag in order to harvest useful power."

"One of our contributions is to suggest that the Betz limit of 16/27≈59% should in fact hold true for any device that harvests power through drag or torque in a horizontal-axis rotational motion perpendicular to the wind field, which is not only the case of conventional wind turbines but also of Loyd's drag power Airborne Wind Energy (AWE) systems."

 

AWE drag power systems are also called "flygens" (Makani), and the same statement (...16/27..) can be made for rotating AWE systems like Daisy or Rotating Reel or SuperTurbine (tm).

AWE lift power systems are pumping mode, also called yoyo or reel-out/in systems.

Is the torque winning over the traction?”

Group: AirborneWindEnergy Message: 24293 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Available power in the wind

 

The Betz limit applied to Airborne Wind Energy 

 

 

 

states:

 

 

 

"•

 

AWE drag power systems can harvest up to 16/27 of the power available in the wind.

 

 

AWE lift power systems can harvest up to 4/27 of the power available in the wind.

 

 

AWE lift power systems require aerodynamic drag in order to harvest useful power."

 

"One of our contributions is to suggest that the Betz limit of 16/27≈59% should in fact hold true for any device that harvests power through drag or torque in a horizontal-axis rotational motion perpendicular to the wind field, which is not only the case of conventional wind turbines but also of Loyd's drag power Airborne Wind Energy (AWE) systems."

 

 

 

AWE drag power systems are also called "flygens" (Makani), and the same statement (...16/27..) can be made for rotating AWE systems like Daisy or Rotating Reel or SuperTurbine (tm).

 

AWE lift power systems are pumping mode, also called yoyo or reel-out/in systems.

 

Is the torque winning over the traction?”

 

Group: AirborneWindEnergy Message: 24294 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind
The error is to make Betz the first-order criteria for AWES ranking, when power-to-weight, LCOE, and many other engineering factors are far more important.

For conventional wind turbines that sit on a tower, with a surface-limited frontal wind resource, old Betz has predictive value, giving a rough match to practice. In aviation, however, power-to-mass is the most predictive factor. We know by experience that flygens suffer fatally under cubic mass scaling law, so we predict they cannot unit-scale as well as groundgen AWES. Makani's secret power curves would surely confirm basic physical theory.



 

 

The Betz limit applied to Airborne Wind Energy 

 

 

 

states:

 

 

 

"•

 

AWE drag power systems can harvest up to 16/27 of the power available in the wind.

 

 

AWE lift power systems can harvest up to 4/27 of the power available in the wind.

 

 

AWE lift power systems require aerodynamic drag in order to harvest useful power."

 

"One of our contributions is to suggest that the Betz limit of 16/27≈59% should in fact hold true for any device that harvests power through drag or torque in a horizontal-axis rotational motion perpendicular to the wind field, which is not only the case of conventional wind turbines but also of Loyd's drag power Airborne Wind Energy (AWE) systems."

 

 

 

AWE drag power systems are also called "flygens" (Makani), and the same statement (...16/27..) can be made for rotating AWE systems like Daisy or Rotating Reel or SuperTurbine (tm).

 

AWE lift power systems are pumping mode, also called yoyo or reel-out/in systems.

 

Is the torque winning over the traction?”

 

Group: AirborneWindEnergy Message: 24295 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Available power in the wind

Click on https://www.researchgate.net/publication/324448503_The_Betz_limit_applied_to_Airborne_Wind_Energy then on request full-text button.

The numbers are quite realistic. In the concluding remarks it is mentioned that: "... we proposed a generalization of the Betz theory by including a share of power due to the downwind translation of the actuator disc, which can be seen as the tether reel-out speed."

 

Here is some example for a 100 m² HAWT vs a 100 m² full surface. Wind speed = 10 m/s, air density = 1.2.

  • HAWT: the power at Betz limit is 1/2 x 100 x 1.2 x 1000 x 16/27 = 35555 W.
  • Now the full surface of 100 m²: the traction (force) is 1/2 x 100 x 1.2 x 100 = 6000 N. Let us reel-out this surface in the optimal speed of 1/3 wind speed, considering the wind speed on the surface is now only 2/3 wind speed, leading to the result: 20000 x 4/9 = 8888 W, so exactly 1/4 of 35555 W. Some explains: 20000 = 6000 N X 3.33 m/s reel-out speed, and 4/9 is 2/3² as the wind force is squared.

The authors use far more elegant means to prove their statements.

 

 

 

 

Group: AirborneWindEnergy Message: 24296 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Available power in the wind

The error is giving an opinion about a scientific paper without reading it.

 

 

 

 

Group: AirborneWindEnergy Message: 24297 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind
I can't read the paper, its behind a paywall. Its their moral error to make academic literature a cash commodity. The knowledge here is free. Let whoever can read the paper confirm or refute my educated guess that power-to-mass was ignored in their choosing Betz as a first order factor. The authors seem like novices starting out as best they can to understand AWE. Let time tell how far they go.

16/27 is acceptable to all of us as the ideal Betz calculation, but very unrealistic numeric basis for predicting flygen superiority, since its mass is parasitic to performance. Also keep in mind that for a pilot-lifter lifting a HAWT flygen, the true frontal area includes the pilot-lifter. Similarly, if a flygen HAWT is tilted for needed lift, rather than use a lifter-kite, that lowers available power.

Lets agree that by disregarding flying mass, and only focusing on Betz, the conventional HAWT always wins, but that's not a very realistic AWES design, to disregard mass; that's not how kites really work. Makani's M600 architecture ideally needs hurricane-force winds to well overcome its high parasitic mass, even if its turbines are 16/27 perfect.



 

The error is giving an opinion about a scientific paper without reading it.

 

 

 

 

Group: AirborneWindEnergy Message: 24298 From: dave santos Date: 12/8/2018
Subject: Re: Available power in the wind
Another questionable assumption in the abstract is that reeling-AWES is the right comparison model, as if crosswind lift motion did not exist in Payne, Hadzicki, Goldstein, etc. 4/27 can be considered a "realistic" ideal (oxymoron) for the reeling case, even as reeling itself may have no realistic future.

The best commercial turbines do not reach Betz, for many reasons, especially since best performance (~50%) is limited to a narrow wind range, and realistic wind just does not blow only ideally.

Its worth reminding as well that most of our AWES do not harvest a small disc area, they harvest a fraction of a large kite window. Guessing the paper cited does not do a careful comparison to actual kite trajectories in a realistic kite window. The real numbers are very low efficiency even if the power extracted is cheaper than a higher efficiency turbine.

I would not risk paying for this paper based on the abstract provided. Has anyone actually bought it?



 

I can't read the paper, its behind a paywall. Its their moral error to make academic literature a cash commodity. The knowledge here is free. Let whoever can read the paper confirm or refute my educated guess that power-to-mass was ignored in their choosing Betz as a first order factor. The authors seem like novices starting out as best they can to understand AWE. Let time tell how far they go.

16/27 is acceptable to all of us as the ideal Betz calculation, but very unrealistic numeric basis for predicting flygen superiority, since its mass is parasitic to performance. Also keep in mind that for a pilot-lifter lifting a HAWT flygen, the true frontal area includes the pilot-lifter. Similarly, if a flygen HAWT is tilted for needed lift, rather than use a lifter-kite, that lowers available power.

Lets agree that by disregarding flying mass, and only focusing on Betz, the conventional HAWT always wins, but that's not a very realistic AWES design, to disregard mass; that's not how kites really work. Makani's M600 architecture ideally needs hurricane-force winds to well overcome its high parasitic mass, even if its turbines are 16/27 perfect.

On ‎Saturday‎, ‎December‎ ‎8‎, ‎2018‎ ‎02‎:‎02‎:‎52‎ ‎PM‎ ‎PST, Pierre BENHAIEM pierre-benhaiem@orange.fr [AirborneWindEnergy] <AirborneWindEnergy@yahoogroups.com


 

The error is giving an opinion about a scientific paper without reading it.

 

 

 

 

Group: AirborneWindEnergy Message: 24299 From: Pierre BENHAIEM Date: 12/8/2018
Subject: Re: Available power in the wind
Attachments :

    In fact a Makani flygen uses more than 4 times the area that would be used in to reach the Betz limit, that due to flight requirements. So the difference between a lift power unity and a drag power unity can be small. But, unlike lift unities, several drag unities could be used in the same swept area: see the circling radius that is about 5 times the wing span, then calculate the swept area in regard to the wing area. In the end drag power systems would use far less land/space, saving the economy of any secondary use.

     

     

     

      @@attachment@@
    Group: AirborneWindEnergy Message: 24300 From: Pierre BENHAIEM Date: 12/8/2018
    Subject: Re: Available power in the wind

    As I indicated previously clik on https://www.researchgate.net/publication/324448503_The_Betz_limit_applied_to_Airborne_Wind_Energy then on request for full-text blue button. I did it. 

     

     

     

     

    Group: AirborneWindEnergy Message: 24301 From: dave santos Date: 12/8/2018
    Subject: Re: Available power in the wind [1 Attachment]
    Its more complex than any Betz-dependent logic. Makani's architecture could actually need more land buffer due to the high-velocity high-mass risk. There are also conductance losses, and a conducting tether is much heavier. The best way to settle who is best in an aerospace context is a careful fly-off program, but that's not how AWE stealth ventures raise big money (they make over-optimistic predictions instead).

    Loyd himself regrets not being more carefully descriptive how he chose and named concepts, like "lift" and "drag" AWES. A better naming approach is "turbine-on-a-wing", "reeling", "crosswind-kite", and so on. Some AWE players seem unable to think beyond the choices Loyd regrets. He named Payne as his inspiration, but did not include Payne's kite motion pick, in order to simplify his initial analysis.

    Pierre seems to be predicting Makani's architecture to be superior to any crosswind soft kite basis, based on a pay-to-play reference. I am confident Makani's secret power curves, in relation to most probable wind velocity, prove poor turbine-on-a-wing scalability and poor power-to-weight performance, compared to soft power kites, and further; that the more dangerous Makani architecture (under FAA metrics) will require more land, especially compared to dense crosswind kite networks.

    Time will settle who was right in theoretic AWE.



     
    [Attachment(s) from Pierre BENHAIEM included below]

    In fact a Makani flygen uses more than 4 times the area that would be used in to reach the Betz limit, that due to flight requirements. So the difference between a lift power unity and a drag power unity can be small. But, unlike lift unities, several drag unities could be used in the same swept area: see the circling radius that is about 5 times the wing span, then calculate the swept area in regard to the wing area. In the end drag power systems would use far less land/space, saving the economy of any secondary use.

     

     

     

    Group: AirborneWindEnergy Message: 24302 From: dave santos Date: 12/8/2018
    Subject: Re: Available power in the wind
    I was blocked, for lack of an institutional email address. Let Pierre copy and paste any text that show the authors included power-to-mass, non-reeling crosswind groundgen AWES, and other factors claimed more relevant than Betz alone.



     

    Its more complex than any Betz-dependent logic. Makani's architecture could actually need more land buffer due to the high-velocity high-mass risk. There are also conductance losses, and a conducting tether is much heavier. The best way to settle who is best in an aerospace context is a careful fly-off program, but that's not how AWE stealth ventures raise big money (they make over-optimistic predictions instead).

    Loyd himself regrets not being more carefully descriptive how he chose and named concepts, like "lift" and "drag" AWES. A better naming approach is "turbine-on-a-wing", "reeling", "crosswind-kite", and so on. Some AWE players seem unable to think beyond the choices Loyd regrets. He named Payne as his inspiration, but did not include Payne's kite motion pick, in order to simplify his initial analysis.

    Pierre seems to be predicting Makani's architecture to be superior to any crosswind soft kite basis, based on a pay-to-play reference. I am confident Makani's secret power curves, in relation to most probable wind velocity, prove poor turbine-on-a-wing scalability and poor power-to-weight performance, compared to soft power kites, and further; that the more dangerous Makani architecture (under FAA metrics) will require more land, especially compared to dense crosswind kite networks.

    Time will settle who was right in theoretic AWE.

    On ‎Saturday‎, ‎December‎ ‎8‎, ‎2018‎ ‎03‎:‎41‎:‎19‎ ‎PM‎ ‎PST, Pierre BENHAIEM pierre-benhaiem@orange.fr [AirborneWindEnergy] <AirborneWindEnergy@yahoogroups.com


     
    [Attachment(s) from Pierre BENHAIEM included below]

    In fact a Makani flygen uses more than 4 times the area that would be used in to reach the Betz limit, that due to flight requirements. So the difference between a lift power unity and a drag power unity can be small. But, unlike lift unities, several drag unities could be used in the same swept area: see the circling radius that is about 5 times the wing span, then calculate the swept area in regard to the wing area. In the end drag power systems would use far less land/space, saving the economy of any secondary use.

     

     

     

    Group: AirborneWindEnergy Message: 24303 From: dave santos Date: 12/8/2018
    Subject: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", and p
    Here are quotes from 2015 Swiss kite power efficiency paper cited at bottom, to further support my views on Betz, "lift power", and power-to-weight (close equivalence to "strength-to-weight")-

    "Unfortunately, the Betz limit cannot meaningfully be applied to kites as the area a kite moves in is generally very large and the kitemwill only remove a small fraction of the wind energy passing through that area"

    "[Loyd's] main result was that almost equally high powers can be generated in the ‘lift’
    and drag’ power configurations."

    "the ‘lift power’ configuration is in fact optimal, which means that, in this configuration, a
    wing generates its maximum aerodynamic power
    "

    "the minimum (best, in terms of efficiency) value of Mg |~ Faero| is determined by the system strength-to-weight ratio, i.e. the ratio between the maximum aerodynamic force the system will tolerate and the mass of all airborne components."

    "Skysails’ flexible wing does not have a high lift-to-drag ratio, but it has a very high strength-to-weight ratio. Ampyx wing has a high lift-to-drag ratio, but a far lower strength-to-weight ratio, and is undoubtedly more costly to manufacture per square meter of wing. "

    ===========
    Analysis of the Maximum Efficiency of Kite-Power Systems

    S. Costello,1, a) C. Costello,2, b) G. Fran¸cois,1, c) and D. Bonvin1, d) 1)Laboratoire d’Automatique, Ecole Polytechnique F´ed´erale de Lausanne
    CH-1015 Lausanne, Switzerland 2)Department of Mechanical Engineering, Institute of Technology Tallaght,
    Ireland
    (Dated: 8 April 2015)

    Group: AirborneWindEnergy Message: 24304 From: dave santos Date: 12/8/2018
    Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a
    Clearing up a point of confusion about [Loyd, 1980]-

    Loyd's "Lift Power" class properly applies to pure crosswind motion of any power kite, not just turbine-on-a-wing designs. 

    Loyd's "Drag Power" class only closely represents the high cycle losses of reeling downwind. 

    The most promising AWES architectures are neither turbine-on-a-wing or reeling based. Loyd did not actually consider the probable most promising architecture (simple wing in pure crosswind motion), a major omission. 

    In my 2013 phone discussion with Loyd, he blamed this ontological confusion on a lack of knowing just how classic his paper would prove, or he would have been far more careful. For all its flaws, [Loyd, 1980] remains the most classic AWE paper. 



     

    Here are quotes from 2015 Swiss kite power efficiency paper cited at bottom, to further support my views on Betz, "lift power", and power-to-weight (close equivalence to "strength-to-weight")-

    "Unfortunately, the Betz limit cannot meaningfully be applied to kites as the area a kite moves in is generally very large and the kitemwill only remove a small fraction of the wind energy passing through that area"

    "[Loyd's] main result was that almost equally high powers can be generated in the ‘lift’
    and drag’ power configurations."

    "the ‘lift power’ configuration is in fact optimal, which means that, in this configuration, a
    wing generates its maximum aerodynamic power
    "

    "the minimum (best, in terms of efficiency) value of Mg |~ Faero| is determined by the system strength-to-weight ratio, i.e. the ratio between the maximum aerodynamic force the system will tolerate and the mass of all airborne components."

    "Skysails’ flexible wing does not have a high lift-to-drag ratio, but it has a very high strength-to-weight ratio. Ampyx wing has a high lift-to-drag ratio, but a far lower strength-to-weight ratio, and is undoubtedly more costly to manufacture per square meter of wing. "

    ===========
    Analysis of the Maximum Efficiency of Kite-Power Systems

    S. Costello,1, a) C. Costello,2, b) G. Fran¸cois,1, c) and D. Bonvin1, d) 1)Laboratoire d’Automatique, Ecole Polytechnique F´ed´erale de Lausanne
    CH-1015 Lausanne, Switzerland 2)Department of Mechanical Engineering, Institute of Technology Tallaght,
    Ireland
    (Dated: 8 April 2015)

    Group: AirborneWindEnergy Message: 24305 From: Pierre BENHAIEM Date: 12/8/2018
    Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a

    Costello's paper uses the current model of analysing kite's efficiency in regard to its area, while De Lellis's paper uses the swept area. As I indicated previously lift and drag power single wings use far more swept area than it would be required in order to achieve Betz limit. One can deduce than drag power systems can better maximize their swept area by implementing several wings as "blades".

    Betz limit is a serious concern leading to an evaluation of land/space use, but within the global land/space use that is determined with the tether length as the radius of the used areas and volumes.

     

    Consider also about the weight aloft for lift vs drag systems: "Airborne Wind Energy Systems: A review of the technologies" page 1473 https://www.sciencedirect.com/science/article/pii/S1364032115007005 (pdf available): "7.1.Effectof flying mass In all AWESs,increasing the flying mass decreases thet ension of the cables.Since Ground-Gen systems rely on cables tension to generate electricity,a higher mass of the aircraft and/or cables decreases the energy production [107] and should not be neglected when modelling [109]. On the contrary,increasing the flying mass inFly-Gensystems doesnot affect the energy production even though it still reduces the tension of the cable. Indeed, as a first approximation,t he basic equations of Fly-Gen power production do not change if the aircraft/cable massis included and this is also supported by experimental data [108]. "

     

     

     

     

     

     

     

     

     

     

    Group: AirborneWindEnergy Message: 24306 From: Pierre BENHAIEM Date: 12/8/2018
    Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a

    "Loyd's "Drag Power" class only closely represents the high cycle losses of reeling downwind. "

    No. There is no reeling downwind for "Drag Power" as unlike lift power systems they don't use any downwind translation of their actuator disk (swept area).

     

     

     

     

    Group: AirborneWindEnergy Message: 24307 From: Pierre BENHAIEM Date: 12/8/2018
    Subject: Re: Kite-Power Efficiency (Betz unsuitablity, Loyd's "lift power", a

    From Loyd's "Crosswind Kite Power": "

     

     

    When a cross wind kite pulls a load downwind, as described

     

    above, it is essentially the lift of the kite that acts on the tether

     

    to produce power.

     

     

    Power can also be produced by loading the

     

     

    kite with additional drag. Air turbines on the kite result in

     

     

    drag power.

     

     

     

    "

    So I precise again that there is no reeling downwind for "Drag Power".  "Loyd's "Drag Power" class only closely represents the high cycle losses of reeling downwind. " is a wrong statement, showing a lack of understanding of the basis. Please read and try to understand the fondamental of the scientific papers before wrongly comment them. Thanks.

     

     

     

     

     

    Group: AirborneWindEnergy Message: 24308 From: tallakt Date: 12/9/2018
    Subject: Re: Available power in the wind
    I did get the paywall paper for free, eventually, and its a good read.

    Like the Betz limit described on wikipedia, most practical issues are not considered, and the limit serves only as an upper bound to produced energy.

    I believe its a good tool, even better with the details in this paper. I have to mention that this is not new, the exact same things are described in the first release of the AWE book, chapter one.

    I think the most important use for the limit is that when you are approachibg or exceeding it, you have gone to scifi land. Otherwise it may be relevant for a windfarm where ground stations are limited to a smaller area. For most AWE, I hope it doesnt have much importance, in that case we should be building windmills instead
    Group: AirborneWindEnergy Message: 24310 From: benhaiemp Date: 12/9/2018
    Subject: Re: Available power in the wind

    Hi Tallak,


    The paper you allude as "the first release of the AWE book, chapter one." is "Airborne Wind Energy: Basic Concepts and Physical Foundations" and is available on http://homes.esat.kuleuven.be/~highwind/wp-content/uploads/2013/08/Diehl2013a.pdf.


    And "The Betz limit applied to Airborne Wind Energy"  (https://www.researchgate.net/publication/324448503_The_Betz_limit_applied_to_Airborne_Wind_Energy) provides a very different conclusion in regard to the paper you mention (I put it below).

    And it is true that practically a single lift (yoyo) wing system vs a single drag wing system use roughly the same area (see Makani document I joined previously) BUT a same swept area could have (4 times) more drag wings in Y configuration within Betz limit (16/27 before cosine loss), and rotating devices can be closer to the Betz limit.

    In the end reaching the Betz limit can be an element of land use. The responsible of the land use is the tether length going fast with high tension in all wind directions. More an AWE system is close to the Betz limit, more it sweeps large, more the power/land use ratio is high, so more it is economically viable, less preventing secondary uses because less using land.



    "To conclude this discussion on the lost (unusable) power of AWE


    systems, we would like to highlight that this is another point where



    our conclusions differ from those in Ref. [13], Sect. 1.4, p. 17. In that




    work it was claimed that both lift and drag mode AWE machines, at


    their optimal operating point, would dissipate 2/3 of the total


    harvested power as losses, whereas only 1/3 would correspond to


    usable power. In contrast, we have here demonstrated that a drag



    mode AWE system at its optimal point with no parasitic drag could




    have all of its harvested power as usable one, whereas a lift mode


    AWE system at its optimal point would actually need to dissipate


    the same amount of usable power as losses."

    Group: AirborneWindEnergy Message: 24311 From: benhaiemp Date: 12/9/2018
    Subject: Re: Available power in the wind

    The link doesn't work, so I put it again (and again as I put it previously).

    https://www.researchgate.net/publication/324448503_The_Betz_limit_applied_to_Airborne_Wind_Energy 

    then click on request full-text blue button.

    Group: AirborneWindEnergy Message: 24312 From: dave santos Date: 12/9/2018
    Subject: Re: Available power in the wind
    Betz is an old tired topic on this Forum, especially its fatal limitations as an AWE metric compared to other figures-of-merit, as [Costello et al, 2015] concurs.

    We are so beyond Betz analysis that we know that an Archimedes Screw, the most primitive turbine design (with toy-kite version by our pal Brasington, sold by New Tech Kites) can beat it. How? Betz simplistically presumes a 2D disc, but the screw has 3D depth, and entrains flow all along its depth to arbitrary high values exceeding Betz assumptions, even impossible


     

    The link doesn't work, so I put it again (and again as I put it previously).

    https://www.researchgate.net/publication/324448503_The_Betz_limit_applied_to_Airborne_Wind_Energy 

    then click on request full-text blue button.

    Group: AirborneWindEnergy Message: 24313 From: Pierre BENHAIEM Date: 12/9/2018
    Subject: Re: Available power in the wind

    What a great thought!

     

     

     

     

    Group: AirborneWindEnergy Message: 24314 From: dave santos Date: 12/9/2018
    Subject: Review: Power-to-Weight as top AWES Figure-of-Merit
    In aerospace engineering, power-to-weight is the top number, given the fundamental physics of flight. Here on the AWES Forum, we have refined power-to-weight analysis in light of "rag-and-string" kite practice. This accords well with AWES LCOE as well, as power-to-cost, and highest safety by lowest mass and velocity.

    In summary, we found our engineering super-polymers to be the sole working basis of highest AWES power-to-weight. Our theoretic ideal is minimal polymer mass at its design working-load, matched to load demand. This is what racing-kite pros do when they match a kite from their kite quiver to conditions. No other AWES paradigm comes close to the maximal power-to-weight efficiency of this principle.

    Ignorance of power-to-weight as the top AWES figure-of-merit leads to fatal design errors, like adding all sorts of non-working mass aloft (flygens, avionics, launching aids, etc). Researchers from non-aerospace backgrounds grasp at Betz* and other sub-optimal analytics. It becomes necessary for high-complexity designs like Makani's M600, with very poor power-to-weight, to fail their naïve expectations.

    The fundamental aerospace-physics prediction still stands- highest power-to-weight AWES design will ultimately prevail.

    -------
    * as if lack of frontal airspace was the top design issue


    Group: AirborneWindEnergy Message: 24315 From: dave santos Date: 12/9/2018
    Subject: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" case)
    Loyd was in a hurry when he wrote his classic Crosswind Power paper; after all, he was an avid kite flyer, always wanting to fly. 

    Loyd chose "turbine-on-a-wing" "drag" architecture specifically to reuse Betz wind energy math, not because it seemed obvious from a design standpoint. We are able to generalize his drag term as equivalent to applying flaps or stall-angle to a wing, which is how a power kite powers-up. We also have noted that a turbine-on-a-looping-wing is a turbine-on-a-turbine, which compounds Betz Limit loss*.

    Keep these facts in mind when reviewing Betz claims in AWE.

    ====
    * As agreed by DougS. 

    Adding to previous post, Doug's SuperTurbine variants that align with the wind are 2nd "Betz-beater" example. Betz paradoxes resolve in a 3D field-theory model of wind turbine dynamics.

    Group: AirborneWindEnergy Message: 24316 From: Pierre BENHAIEM Date: 12/9/2018
    Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c

    DaveS' analysis is both deep and right: "Loyd was in a hurry when he wrote his classic Crosswind Power paper; after all, he was an avid kite flyer, always wanting to fly."

    Congratulations to point "these facts".

     

    Albert lives

     

     

     

     

     

    Group: AirborneWindEnergy Message: 24317 From: tallakt Date: 12/9/2018
    Subject: Re: Available power in the wind
    Id like to mention that the AWE book mentions both 16/27 and 4/27 for drag and lift mode AWE, if I recall correctly (and I hope I do as I pulled the book from my shelf to check this on friday).
    Group: AirborneWindEnergy Message: 24318 From: Peter Sharp Date: 12/9/2018
    Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c
    Attachments :

      Hi DaveS, This quote is probably wrong:

      “We also have noted that a turbine-on-a-looping-wing is a turbine-on-a-turbine, which compounds Betz Limit loss*.

      The reason that it is probably wrong is that the secondary turbine, the ram-air-turbine (RAT), is moving across the wind. So the air that it slows, and which usually accumulates behind the rotor to enforce the Betz limit, is swept away by the true wind coming from the side of the RAT. I have found only one paper on that subject, an old Russian paper, which found that the efficiency of the RAT could be over 80%. So I think that topic needs to be more carefully considered. The Makani kite data probably contain the answer to this question, but they are not available.

      PeteS

       

       

       

      From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
      Sent: Sunday, December 09, 2018 9:03 AM
      To: Yahoogroups <airbornewindenergy@yahoogroups.com

      Group: AirborneWindEnergy Message: 24319 From: dave santos Date: 12/9/2018
      Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c
      A looping foil is a turbine (a wing with angular velocity), subject to Betz Limit. You oddly propose that turbines-on-a-looping foil escape Betz by some principle maybe only known by Makani (a Secret Sauce theory)

      Having been inside of the early Makani venture (via KiteShip) and having closely followed them ever since, I do not know who exactly would ever be able to find an aerodynamic principle unknown to the aerospace field (excepting Dave Culp's soft kite work). Never forget that no one in early Makani had an aerospace background (again, Culp closest, as a Marine Engineer) up to the architectural down-select based on Loyd, which Loyd himself did not think was the optimal architecture.

      Fortunately, the M600 is nearing its definitive fate, settling whether there was any "secret sauce" (there was not).







       

      Hi DaveS, This quote is probably wrong:

      “We also have noted that a turbine-on-a-looping-wing is a turbine-on-a-turbine, which compounds Betz Limit loss*.

      The reason that it is probably wrong is that the secondary turbine, the ram-air-turbine (RAT), is moving across the wind. So the air that it slows, and which usually accumulates behind the rotor to enforce the Betz limit, is swept away by the true wind coming from the side of the RAT. I have found only one paper on that subject, an old Russian paper, which found that the efficiency of the RAT could be over 80%. So I think that topic needs to be more carefully considered. The Makani kite data probably contain the answer to this question, but they are not available.

      PeteS

       

       

       

      From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
      Sent: Sunday, December 09, 2018 9:03 AM
      To: Yahoogroups <airbornewindenergy@yahoogroups.com

      Group: AirborneWindEnergy Message: 24320 From: benhaiemp Date: 12/9/2018
      Subject: Re: Review: Turbine-on-a-wing Reanalysis (and second "Betz-beater" c
      Peter Allen Sharp is right. Please see on http://ejurnal.bppt.go.id/digilib/sampul/9781119975441.pdf : "innovation in wind turbine design" (Peter Jamieson), pages 128 and 129 about secondary rotors with the whole calculation and a figure. On page 128: "It has sparked a few misconceptions. One is that the Betz limit will apply twice to the overall power conversion...". It is demonstrated.