COTS AWE depends on standard wings, whose extensive R&D is in effect direct COTS AWE R&D.

Ongoing high-end parafoil refinement, like small LE rods and better reflex-foil handling, representative of innovation occurring across many designers; sixty years of progress, and no end in sight. 27m2 wing featured is near L/D 10, roughly rating 50kW of working AWE output.

From the website-

"Proton 2 was developed from of our revolutionary Proton (1) concept. We were able to keep excellent start and landing properties high-speed stability of the canopy and excellent maximum speed performance from his predecessor.

Thanks to the new leading edge concept, which is now reinforced by plastic rods, the Proton 2 has a 4 km / h faster top speed (now about 70 km / h) than Proton (1) had.
Another significant improvement is the completely redesigned brakes, which not only have less overall line consumption, but they also increased their overall efficiency and reduce break-pressure. And all this while maintaining a pleasant and progressive break-pressure in all flying modes.

What’s new is the use of additional break control (simply the second steering line) that allows for safe and efficient control in full reflex mode (ie, full-trim-off and full speed). Other improvements are completely new risers especially designed to suit hand’s position while flying in full-reflex mode. Trimmers and long speed-system are of course standard feature."

https://axispara.cz/products/ppg-gliders/axis-ppg-proton-2

Nice analysis of reflex PG wing evolution-

http://www.trikebuggy.com/products/dudek/reflexgliders.pdf

Its long been predicted here (since 2009), in great detail, that Makani's high-complexity high-risk AWES architecture would ultimately not scale well, and safety-reliability-cost targets would be missed. That is why its unsurprising that Makani has gone silent; there are no open job openings, and our Hawaii spotter has no news regarding planned M600 Hawaii trials. GoogleX does not in fact "embrace failure", so we expect no open-knowledge post-mortem. Instead, the analytic critiques made here over the years seem to stand. Its even hard to imagine GoogleX can even sell off Makani, like other X fizzles, and the remaining mystery is how they exit or radically "retool".

A reverse trend back toward soft power kites and ground gens is widely noted in the AWE community, with a pack of active contenders developing new prototypes at utility scale. The prediction here is that this trend will hold, and ultimately lead forward to successful multi-kite formations. Wubbo Lives.

As we have carefully explored kite dynamics, many surprizing lessons turned out to be far more general than anyone expected. We found observable aerospace dynamics of kites shared across many scientific and engineering fields, from microscopic QM physics, to biological cases, to metamaterials, and orbital mechanics; across a seemingly unbounded scale and frequency spectrum.

Previous pondering left off with tether-based sonic black-hole/white-hole analogs in the form of high-speed rope-driving pulley-loops. This post extends the cosmological kite analogy by incorporating widely believed wormhole/cosmic-string structure linking blackholes and whiteholes. Typical kite-like calculations across physics solve like this cosmic string case-

"each individual ‘cosmic string’ turns out to be a cylindrical wormhole leading to the other sheet of three-dimensional space." https://arxiv.org/pdf/gr-qc/9502033.pdf

While Black Holes are now well confirmed by observation, expected Whiteholes have until now been elusive. A whitehole is a blackhole run backwards in time. The latest hypothesis is that specific gamma-bursts observed in cosmic voids are in fact the missing Whiteholes. This accords with our pulley loop sonic relativity analog, where speed-of-sound stands in for speed-of-light, and Mach between loop sides is relative, especially when the loop is driven (but always appears as Mach1 "c" to an observer internal to the loop). Our sort of sonic relativity gedanken suggests why a blackhole lingers (Doppler red-shifted) while a whitehole pops (Doppler blue-shifted).

In our kite model, a simple twisted or untwisted string corresponds to simple twisted or untwisted spacetime, and a wormhole corresponds to a kitestring core tube topology, which can be braided as well. All the basic permutations of abstract knot and braid theory seem possible in any string-like world.

Once again, no claim is made that a classic kite is literally the same thing as its microscopic or cosmic QM cousins; after all, we distinguish them as carefully as we relate them. What is hypothesized is that deep fundamental kite principles share across all scales and varieties of matter; that the kite offers a wonderful analog case to help understand all the rest, and vice-versa. This is not just wonderful fun, but crucial AWES concepts may thereby be inspired.

TUDelft first hosted Loyd's paper years ago, the most chewed-over AWE text of all, but the file disappeared. Here is a new location-


M.L. LOYD. "Crosswind kite power (for large-scale wind power production)" Journal of Energy, Vol. 4, No. 3 (1980), pp. 106-111.

https://doi.org/10.2514/3.48021
redirects to
https://arc.aiaa.org/doi/abs/10.2514/3.48021

A statistical romp thru AWE scholarly publishing and patent filings. Not included in the respective data sets were AWE's non-patent non-publishing ventures, DIY Open AWE's social media, Joe's vast AWE web archives, formidable aviation and hobby-sport kite cultures, major press coverage, militarized AWE R&D. etc.. Sometimes a blitz of patents or academia do dominate, but a single key paper or patent outclasses any amount of junk; that's the great AWE race. Time will prove how much sheer bulk of formal papers and patents (mis)predicted ultimate AWE (excepting the handful of pioneering AWE texts and patents).

Sustainability 2017, 9(6), 915; doi:10.3390/su9060915
Review
Comparing Patent and Scientific Literature in Airborne Wind Energy
Anny Key de Souza Mendonça *, Caroline Rodrigues Vaz, Álvaro Guillermo Rojas Lezana, Cristiane Alves Anacleto and Edson Pacheco Paladini
Department of Industrial and Systems Engineering, Federal University of Santa Catarina, Florianópolis, 88040-900 Santa Catarina, Brazil

http://www.mdpi.com/2071-1050/9/6/915/htm

SkySails' is fully resurgent on land, ongoingly developing ship-kite derived groundgen AWES. The fresh onshore focus is consistent with early KiteLab finding that offshore is not the best place to develop AWES, but SkySails' pioneering sea trials did well prepare them for more effective land work. Note that kPower already claims to have been first in "automatic continuous operation" of an AWES, by a two week session at kFarm, but this was a small prototype based just on passive control using a self relaunching sled pilot kite to lift a looping power parafoil. SkySails and partners intend a far larger more complex AWES to validate automatic continuous operation. The prediction here is that the system will modestly succeed, subject to upsets requiring human intervention, and output sapped by high reeling return cycle loss, eventually leading to constant trajectory-surface adoption.

"The aim of the project is the first development and construction of a fully automated "SkyPower100" airborne wind energy system with a nominal capacity of 100 kW. This system allows the autonomous long-term operation day and night as well as automatic launching, landing and stowing of the kite"

https://www.skypower100.de/english/

There is a flurry of industrial news articles about SkyPower that do not yet add much new detail to the new initiative.

SkyPower100 partners circle-

SkySails Power GmbH (project coordination)
Luisenweg 40, 20537 Hamburg, Germany

EnBW Energie Baden-Württemberg AG
Durlacher Allee 93, 76131 Karlsruhe, Germany

Leibniz Universität Hannover -
Institut für Antriebssysteme und Leistungselektronik
Welfengarten 1, 30167 Hannover, Germany

EWE Offshore Service & Solutions GmbH
Donnerschweer Str. 22-26, 26123 Oldenburg, Germany

Access denied to non-registered viewers. Can the relevant text be sampled here?

The modern HAWT finally passed 100kW output after almost 2000yrs of prior wind turbine evolution. AWE is now reaching 100kW performance after less than 200yrs of specialized prior art. The ~10x higher rate of AWE progress owes a lot to the general civilizational acceleration in tech advance, driven by a larger more capable engineering community, and better technical communication. There is no known unsurmountable barrier to continued accelerated progressin AWE; just keep working hard and enjoy the sweet R&D paradise. Wubbo Lives.

Heisenburg on his deathbed wondered, "why turbulence?".

Best answer; to make kite flight interesting.

Import of turbulence to AWE ranges from wild wind to wing response and wake effects. Rotational Coherence is the new science lens. Scrolling sheets create spiral lines, the same math works across all fluid/gas mass-energy phases. QM turbulence criteria apply to vast persistent vortices in sea and sky, quasi-superfluids. Dolphin bubble rings are still hot sci, but now labs are do the trick in tanks with ring hydro-foils, and even tie vortex knots, seen as models for all sorts of exotic coherence-chaos order-entropy physics. See our twisted and braided kite-strings and dancing kites in the heady magic.

Fresh turbulence science-

https://en.wikipedia.org/wiki/Lagrangian_coherent_structure

Coherent Lagrangian vortices: The black holes of turbulence G. Haller1† and F. J. Beron-Vera21 Institute for Mechanical Systems, ETH Zurich, Zurich, Switzerland 2 Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami FL, USA

https://arxiv.org/pdf/1308.2352v1.pdf

https://en.wikipedia.org/wiki/Coherent_turbulent_structure

https://www.livescience.com/27657-knotted-vortices-unravel-truths-for-physicists.html

Hurray for utility-scale paravane energy, AWE's Neptunian sibling, wet for the first time. Expect positive results, after a shake-down phase prone to delays. Initial design weaknesses will promptly emerge. The unit could even crash into the bottom in a control failure. It all works out in due time-

http://renews.biz/111666/minesto-preps-welsh-tidal/

Soft kite and networked kite partisans are counter-betting that aircraft scaling laws, aviation safety, and aerospace economics prevent high-complexity rigid wing VTOL from becoming a true utility scale solution, at least for a few decades. Meanwhile, ship-kite-scale power-kites have the highest proven capacity at lowest capital cost. What makes it seem like a close race between the two major AWE camps is the superior allure to non-expert venture capitalists of high complexity architectures. No amount of excess early capital and hype can really change engineering truth, that AWE tech can only prevail on inherent merits. The social benefit is enormous to eliminate AWE's losing architectures by spending them away. A winning AWES architecture coming from the open kite community must bootstrap itself virally in sheer Darwinian fitness, with far less capital need than the also worthy testing out of poor ideas. Enjoy the contest-


http://www.stw.nl/nl/content/vtol-rigid-wing-airborne-wing-energy

Sampling of current KP research documentation-

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Good intro to wing performance in AWE context, with sim data. Validates claim made here regarding higher L/D by lower wingloading, and implies that pulling all kite lines collectively, while also turning, can increase turn rate, but does not consider a mixed push-turn that sport kite fliers use-

http://iopscience.iop.org/article/10.1088/1742-6596/1037/5/052004/pdf

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A 3D model peek at KP's VTOL quad concept, recalling Makani Wing7-

https://github.com/RigidWing/sitl_gazebo

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Integrating kite topology into open drone codebase-

https://github.com/RigidWing/PX4_KiteX
https://github.com/RigidWing/PX4_Kitepower

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Full text not yet located; topic recalling Aussie kite turning thesis noted here some years ago-

van Reijen M 2018 The turning of kites.
Master thesis, Delft University of Technology

More far-out tether-engineering ideas-

Imagine in deep space a vast tether hoop rotating at nearly the speed of light. It would have to be a hoop big enough for its curvature to be flat enough that it would not fly apart. If such a tether-hoop could be spun-up, it would contain vast flywheel energy. If an ordinary slow-moving object were to collide with such a hoop, it would be cut right through without cutting the hoop. A cosmic tether-hoop could be fed, tapped, or moved by magnetic or optical forces. Concentric hoops could counter-rotate close to each other, allowing for differential pumping and tapping by a stationary transducer basis. A Dyson-sphere variant could be made from geodesic networks of spinning hoops.

On a more down-to-Earth flying hoop note, Culp's Flying Rope kite concept could also work as a Flying Snake* glider, suitably ballasted along its length. This could be a winged string, loose, branched, or hooped, and it won't be hard to put little paper wings and weights all along a string and make them fly as they will. It should be possible to imitate bird flock V-formation flight and many other interesting effects. Helpful tricks include bit of drogue force acting on rearward units, dihedral winglets, reflex foil sections, etc., to enable loose flight. Hooped flight can be pumped, lasso-style, for lasso slow-flight (compared to unwinged rope).

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* term coined here to distinguish from Flying Rope in kite-train mode

Correction- KP data referenced was experimental, not sim. They used an HQ Hydra valved parafoil (great choice).

Developed tension in large rotating hoop?

Analysis of direct interconnection technique for offshore airborne wind energy systems under normal and fault conditions 

In 2014 someone  at Top Daily Conversations (TDC) selected what they thought would be the

The essential nature of "rag and string" that allows kites also drives many other cultural productions, like rigging and fishing. We study these similarity-cases for clues to bring back into kites. In this spirit we noted the artist, Saraceno, for his aerial visions and string installations, but there was a rich vein of prior string art in the early to mid 20th Century, that escaped us. The link below reviews highlights of that string work.

There are readers who object to mining the Humanities for engineering inspiration, but in the history of innovation the highest engineering science and poetic passion often went together. We must admire the profound instinct that drove Duchamp to install Sixteen Miles of String generations before Saraceno hit on the same effect, and how we might someday string the sky into a new space for human life. How wonderful hat string itself is such a powerful artform, as well as the process medium of the Jacquard Loom, the first address-programmable machine, or the information-theoretic Andean basis of writing, or the ultimate cat-toy, or String/Brane Theory, and so on. The kite is in good company with other amazing string worlds.


http://www.modernedition.com/art-articles/string/string-art-history.html

We continue noting with satisfaction steady advances in all branches of AWE, including Kite Sailing, one of the oldest kite power applications (traditional Polynesia, Pocock, Cody, etc.). Race for Water uses a Skysails AWES and is now headed for Easter Island-

http://en.worldtempus.com/article/events/arts-and-culture/breguet-race-for-water--stopover-in-valparaiso-26221.html

Context- Paravanes in overall tidal power tech-

https://www.envirotech-online.com/news/environmental-laboratory/7/breaking-news/can-we-get-enough-energy-from-the-moon/46708

Review for those who may not know what is the most important number in mobile power engineering (cars, boats, planes, AWES)-

https://en.wikipedia.org/wiki/Power-to-weight_ratio

L/D, TSR, cl, cd, etc. are all secondary numbers that do not by themselves predict true performance.

On the same Power-to-Weight Wikipedia article cited in my previous message, the highest ratio charted is the Space Shuttle engine. The reason cited for such superb performance (153 kW/kg) is "(turbine) ability to operate at very high speeds". Everything else charted is far lower specific power.

How does AWE's COTS baseline concept, the power kite, stack up? One kg of kite in high wind is in the same specific power class as the shuttle and rocket fuel. A kg power kite would be around 10m2, giving 15kw per m2 as the rough power load. This is close to rated PG and parachute max loadings.

The physics puzzler is how a power kite does this without "very high speeds"(?) What jumps to mind is cool scale-relativistic or low-dimensional physics, but its an open question. The deep magic of the power kite still being revealed. Only the Space Shuttle is known to come so close in performance. That's pretty cool.


WP Data

WR RS-24 (SSME) Block I H2 Brayton turbopump[2]
53,690 kW
72,000 hp
153 kW/kg
93 hp/lb
Space Shuttle

Filling an obscure gap in kite-like aviation history, we consider Soviet avant garde artist Valdimir Tatlin's 1932 glider, Letatlin. There are many dimensions to this case; dual futurist and anachronistic form, relation of art and official power, fabric and sticks, genius and ignorance. Could the Letatlin have flown? Yes, marginally. Here we see the echo of Leonardo and premonition of Panamarenko and Saraceno, of wishful aviation, of theoretic airborne utopia. Art and life imitate each other. Summary ridicule of such artistic efforts is Philistine rather than informed.


https://www.atlasobscura.com/articles/the-birdlike-soviet-flying-machine-that-never-quite-took-off

Very limited insight with a major factual oversight, that groundgen mechanical transmission by rope-driving is already well "demonstrated" not just by historical rope drives but many AWE demos ranging from SkySails 2MW rated traction power to TUDelft's 100kW output. Flygen schemes do lack a demonstrated "efficient approach for transmitting power from a high altitude", Makani case notwithstanding.

== copied text ==

"High-Altitude Wind Power

Considering all costs, airborne wind energy could be the world’s cheapest energy source. (Possible exceptions are limited hydro sources and limited situations where surface-based wind turbines may be the most economic for supplying relatively local needs.)

High-energy winds are at altitudes high above us, not just at a few hundred feet where they can be tapped by tower-based turbine rotors. Airborne Wind Energy technologies will employ tethered wind energy capture devices that “fly” to these altitudes where wind power is much greater than it is at ground level.

There are several groups developing Airborne Wind Energy (AWE) technologies intended for use up to 2,000 ft. above ground level (AGL) and others intended for use at altitudes greater than 2,000 ft. AGL. Some technologies might be able to bridge this segmentation, but not always in the exact incarnations for above and below that altitude. The 2,000 ft. was chosen because that is the altitude above which the FAA is not currently interested in approving what it considers to be “obstructions.” AWE technologies can be flown higher outside the 12 nautical mile limit off the coast into international airspace, but still in the U.S. “economic zone.”

Still to be demonstrated is an efficient approach for transmitting power from a high-altitude wind source to the ground where it can be used. The voltage across the connecting cable would be too high using conventional methods. "

https://www.powerelectronics.com/power-management/power-management-chapter-16-wind-power

Attachments :

Its worth noting that the article title, "Inventor Solves Kite Stability Issues", is a forgivable exaggeration. Verna has barely begun to explore stability solutions in his patent work, but best wishes for his eventual success in advancing ship kite art.

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Reply to PeterS-

Verne is featured here for exhaustive completeness, but does present a practical design to compare against. The baseline standards in shipkites are SkySails North Sailmakers' parafoil and KiteShip's OL, both proven in actual ship traction.

The Sharp Rotor needs to be proven against the standard power-kite ship-kite cases, not against primitive ideations like Verna's, with no working examples. Cargo Ships are not expected capable of direct upwind performance due to realtively high frontal aerodrag. Lift to windward must exceed drag by a large amount to be practical.

Note also that we do know that extracting torque reduces available lift of any rotary kite, by extensive experience. Excess mass aloft really saps available torque. For this reason it seems no one is able to make a workable rotor-kite close to the power-to-weight of standard power kites. A Sharp Rotor dependent on lifting gas invokes well-known barriers to economic operation.

Pierre's current experiments are predicted to confirm the known limitations, but tested results that disprove predictions are most welcome.

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Congratulations to E-Kite.

From their tweet- "Global Winner Best Startup at the Talent Unleashed Awards 2017, E-Kite has been invited to a 3 hour lunch with Silicon Valley legend Steve Wozniak (co-founder of Apple)."

https://twitter.com/ekitewps

While such awards do not settle what unjudged method or team may ultimately prevail, the public attention gained for AWE helps us all. E-Kite next faces severe scaling-law challenges to its looping rigid-wing kiteplane platform (which also needs added vertical surface area forward, to reduce side-slip drag and altitude loss in lateral motion phases).

Whoops! Corrected text in caps- "(Verna IP) does NOT present a practical design to compare against"

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Attachments :

PeterS

You seemed to be clearly proposing that the Sharp Rotor is a suitable first-order comparison with Verna's ship-kite concept, rather than invoking proven empirical power-kite ship-kite and kite-sailing practice as the soundest baseline to compare both Verna and Sharp concepts as contenders.

As far as DUW sailing expertise, I made my first working models in 1989, demoed them in public, and inspired PeterW's work. The original work was honored and collected by the Smithsonian Institution Maritime Museum in '92. I also worked with KiteShip and have MOU status with SkySails. I also was scholar-in-residence at the World Kite Museum for seven years, and am a hands-on kite tech expert, not just theoretic. If I "didn't understand" your message, at least it was not from lack of study and experince of related art.

You (and Verna) will be best understood by pointing to working prototypes and supportive third-party analysis, just like anyone else in tech. Sorry if I was wrongly unable to understand your meaning,

daveS


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The quick answer is that ANY* load on the kite reduces L/D.

Its been standard knowledge in AWE for over a decade (and in the wider kite field for over a century) that a kite flies at a certain angle based on its total L/D. Its a poorly linear relation, but as a general "Law", the higher the kite flying angle, the higher the kite L/D. Any load on the kite, like payload or AWE harvesting, causes a roughly proportional loss of L/D. To compensate, a higher lift coefficient is achieved by increased AoA and drag increases.

The most obvious effect of loading is that the kite flies at a lower angle and lower altitude. Among many higher-order non-linearities, excess design kite-mass is toxic to useful lift, stability greatly suffers (the kite is more likely to fall in lulls), and weaker wind lower in the wind gradient can make the kite reach a tipping point insufficient wind-velocity to continue flight. Kite design is the art of the lightest kite that can handle the highest loads. Modern power kites are the highly evolved result, that no other kite basis can currently match.

This basic aerodynamic physics, as combined with Scaling Law factors, operations, economics, regulations, etc. is best-practice for predicting which AWES concepts will work well and which won't. We still need testing of concepts with a poorer mathematical

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* PeterS recently wondered about the effect torque-loading of a rotor kite had on its flight performance, supposing it to be unknown.

Hey, that's Reinhart (behind a new beard), so expect fine work. Expect drone and airframe experimentation to evolve toward his Flysurfer SS expertise in swarm format.

Rod comments as if KiteShip, KiteLabs, PeterL, and kPower teams have not understood scaling laws all along, not just in their SS kite selection, but also in pioneering radical array concepts (to match unit-kite number to giant groundgens). Recall Dave Culp's team effort flying a stack of Flexi's back in the '70s, revolutionizing speed-sailing.

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Pierre,

Please share Sharp Rotor Testing in its own proper subject/topic thread, rather than let it be hidden and conflated in Verna's IP and subject thread

That said, the low L/D you observe is as expected by decades of similar rotor kite precedents. The best academic practice is to test all ideas, to properly falsify or validate, which naturally includes the Sharp Rotor. You are the researcher of the moment, so your findings can attract more research, if seen as truly promising. Looking forward to your power-to-weight measurements, to compare with power kite numbers (or Space Shuttle engine, as covered in its topic),


daveS




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