Congratualtions to TUDelft-incubated Kitepower for a significant milestone. Lots of work still ahead; scaling up is hard work. The link has two video clips. The 100kW claim comes from Roland's Twitter-feed, and no doubt represents a surge peak. ~30kW would be a fine average over an entire pumping cycle with a 40m2 LEI.

https://kitepower.nl/a-40-square-meter-success/

Wubbo Lives

Checking the jobs section of Kitepower's website reveals a strong hiring push. The curious aspect is positions for "rigid wing" work. This could be some existing wing, like maybe Enerkite's, or a even completely new design. This does open up all the standard questions of soft v hard wing concerning scaling, cost, and safety. Maybe we are finally seeing a Northern EU comparative fly-off, that should have been done a decade ago, in earlier capital rounds.

The mechatronics position is likely to work up a launch-land solution missing in current testing. Its really risky to develop critical complex systems depending only on whoever applies, especially in tight talent markets. Another odd detail is the offer of a master's thesis with "support", as a job opening.

The problem looms for the dozen or so known contenders (some dormant) for remote AWES market, that the weak initial market will likely go to just one lean best-of-breed, with perhaps some M&A action. The winner will likely not be based on any exotic gimmick, or major capitalization, but on the simplest cheapest safest most-reliable unit. May the best team win.

Gordon,

Launching and landing giant kites need not be dangerous, and Kitepower's 40m2 wing is still rather small and forgiving.

There was one notable giant soft-kite fatality forty years ago, Eideken, but we know so much more now, and giant kites have since flown safely at countless family events. The primary safety practice is to stay just out of reach of the kite (launching from behind the "top" surface). One could pack a kite for remote launch and Kite Killer's tame landing. Kite pilots enjoy mild excitement, and managed risk is an accepted feature of many "dangerous" activities (like driving).

The major unsolved risk in AWE is not giant multi-line soft-kites but smaller high-mass high-velocity single-line kiteplanes that inherently crash catastrophically, especially if they can breakaway and crash anywhere far afield.

The "Knot Kite" is not a suitable power kite, even for theoretic purposes, as such show-kites are expressly bridled to not power up or develop extra lift, just float and dump gusts. Looking forward to a prototype along lines you envision,

daveS

Wing loading is a critical parameter in aerodynamic design, with complex impacts on performance, but does not get much attention in AWE. While not a direct scaling factor, its influence on so many aspects of flight impose indirect scaling limits. For example, higher wing loading requires higher minimum velocities just to sustain flight, even as most-probable AWE wind velocities remain low. Tether drag is another AWE factor made worse by higher wing loading. Such complexities have made AWE's soft-wing v rigid-wing contest tricky for some developers to sort out.

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

More about Dimitri Cherny's quixotic quest to become a US Congressman, with a single mention of AWE. Disclosure still pending of his final AWES prototyping work, which he purported was successful, as well as a novel sailboat project in progress. Best wishes Dimitri-

https://www.journalscene.com/news/arrington-cherny-hope-to-oust-sanford-in-congressional-gop-race/article_19cd7d34-5ea1-11e8-8ac1-f3c8c95ac120.html

Interesting optimistic opinions on safety cost and other critical parameters*-


https://www.thetimes.co.uk/edition/scotland/giant-kites-make-more-power-than-wind-turbines-hj3s8f2v7

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* "Academics at the university concluded that kite power is “simple and unsophisticated” and that there is no risk to humans and animals from a kite falling from the sky because of their “bendable and soft” construction materials."

Once again reminded in AWE that step-towing is validated to do the job of raising a kite out of surface calm into upper wind, while other schemes, like multicoptering and catapulting, are the outliers.

The rigging shown is rather crude, with many possible snags, so the intent concern on the pilots face is apt.

So we have a ratio of ~75 acres of "terror kite" wildfire to ~100 Palestinians killed by Isreali snipers. A small wildfire complaint does not reconcile with the human life cost of armed occupation.

The overarching ecological catastrophe of Zionism has been the mining of groundwater for EU cash crops, killing many natural springs and groves of ancient trees, and dependent species. Palestinians with kites, by objective comparison, do not own groundwater-based biz enterprises, and are not the top ecological culprit in the region. A range manager concedes that burnt land can be expected to recover in a year or so (wildfire is an normal aspect of ecological resilience). Loss of human life is not so easy to recover.

Its unlikely that Palestinan kites can make any real change in the ~300-1 kill rate of Palestinians, as a military fact. These kites are more of a symbolic expression of unequal self-defense of Palestinian homeland rights against US-provided arms. Consider this analysis as a US liberal reformed-Jew take on Zionist militarism gone wild (based on Shephardic Jewish roots on my Mom's side).

A Rabbi ponders fire kites, but not AWE as such. He sees in the fire kite a belated warning to the Isrealis to not similarly abuse technology lest they come to share common hell with the Gaza kiters. Its not a very coherent vision, nor does it compassionately humanize the Palestinian tragedy, but it does touch on deep questions concerning technology and the fate of us all-


http://www.israelnationalnews.com/News/News.aspx/246942

Hi Gordon,

You are factually correct about how a rower and kite could work as a hybrid, but the complexities raise open questions. The choice of rowing v. biking exercise is mostly personal, with claims on both sides.

There are comparable configurations to ponder, for example, human power applied directly to the generator reduces the load demand on the kite, so it can fly better. This would offer most of the benefits of any more complex rig where the human works inside the kite's motion system. Does the rowing part continue to cycle parasitically when no human is needed, due to good wind? Low wind simply is very energy poor; at some point a human offers superior power, and a kite is just a nuisance.

The hope that extra human power can increase power harvesting may be too unphysical. Can one really add a motor to a kite and really get more power out in better sweeping than the motor itself draws? This is a conjecture that begs to be calculated and tested.

In a good breeze, a power kite's figure eight frequency can match nicely to human motion. Turn-rate is a tunable design quality that sport kite designers select. Figure eights can easily be more-or-less constant pull owing to the steady alternation of potential energy at the top of the pattern with kinetic energy in sweeping across the kite window power zone. "Brake" inputs also smooth pull as needed.

Ultimately, Keep-It-Simple (KIS) rules practical design, but there is also a place for odd ideas and experiments, which always have something to teach,

daveS

A bit of clarification of how a figure eight can easily be designed for passive near-constant pull, given its dynamic similarity to a classic pendulum with alternating potential and kinetic energy, but the sum of the two is always constant; Imagine a spring force added to the output tension that absorbs the surge energy and returns it during recovery phases. This is a standard means in ME to buffer shock loads for constant performance, and the classic pendulum can be sprung for the same effect.

Minesto seems on track in every way except resolving nagging concerns about collisions with sealife. We have discussed possible solutions like prop-guards, which are not seen yet in Minesto's designs, and would have a drag penalty. Slower soft-kite-style paravanes hauling on PTO lines remain an option. Fish sonar integration is another approach, where a paravane might even steer around megafauna rather than pause. Another fish-friendly approach is an Archimedes screw fuselage and swept wings as gentler turbine and wing morphologies. (Open-AWE_IP-Cloud) Bridling near a hot paravane is a toughie; avoidance seems like the only solution. At least the lower tether inherently sweeps slower and safer.

That Minesto is ahead of AWE in practice recapitulates evolutionary sequence where swimming preceded flying. A swimmer does not crash like a flyer. Kite dynamics apply in any fluidic medium, but the practical details vary. Vast paravane farms could be deployed to help maintain ocean currents in their established courses as global warming changes threaten to shift them catastrophically.

A usual mix of facts and optimistic* claims along Ampyx's long developmental track, plus some new floating platform study conclusions-

https://www.windpowermonthly.com/article/1466082/floating-offshore-takes-skies

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* Perhaps an extra decade or two is needed before kiteplane reliability metrics allow mass deployment, and only if SkySails style ship-kites do not prevail.

Minesto AB (publ)

https://www.airseas.com

AirSeas' Airbus connection looks like an employee spin-off without major capitalization, like SkyMill and Boeing a decade ago. Its solid aerospace interest in AWE, as an acknowledged opportunity. Boeing's interest in AWE goes back to Wayne German in the '80s. The aerospace giants are in the AWE game, if not yet betting all, due to the long developmental trajectory. Expect further interest in due stages.

We see a strong convergence of AirSeas' AWES architecture with SkySails'. This reflects that SkySails' architecture was fairly optimal and that most kite patent claims are questionable, given so much prior art. We have traced key art to its antecedents; SkySails' real triumph was its operational experience at sea. Its great to see a third ship-kite company emerge, but lets hope that shipping industry conservatism does not once again prevail.

kPower proposes that ship-kites are the natural utility-scale unit, and works with sport power kites to develop scale prototype AWES with PowerTakeOffs (PTOs), intended to converge with ongoing progress in full scale kites.

Nature once again exceeds imagination; spiders with soft foils doing tether launches in exact correspondence with human paragliding.

--------------------------------------------

Short generic AWE overview from the Northern EU perspective-

https://en.reset.org/blog/wind-power-new-aircraft-flying-high-harvest-green-energy-06052018

Prior article from same venue-

https://en.reset.org/blog/airborne-power-stations-take-wind-energy-new-heights-03122018

Progress in kites has always been by patiently tested refinement of flashes of genius and luck. Peter Lynn is the top contemporary avatar of this classic kitegod tradition. His June newsletter details the current frontier of soft-kite pilot-lifter state-of-the-art. Fresh from triumphs in SS (single-skin) design, he is now brilliantly advancing active-bridle passive-control logic, at age 74. On his good days, PL is greater than ever. Here is AWE techne relentlessly evolving in unsurpassed purity.

Enjoy-

www.peterlynnhimself.com/newsletter/2018/june.html

Having pondered PL's latest report further, further thoughts from the KiteLab/kPower perspective-

- PL does not mention (but surely knows) what KiteLab (and others) have observed, that stretchy nylon tethers offer superior flight stability compared to non-stretchy UHMWPE tethers, by absorbing surge force in gusts and returning "tow" force in lulls. So helpful is this effect that nylon can compete in flight robustness in gusts, despite being weaker.

- Other helpful means of increasing wind range and flight stability exist, and perfected designs may well include multiple means. Variable fabric vents and tails are potential aids to supplement variable bridles.

- Readers of the AWES Forum will recall extensive discussions of active bridles and related details as a form of (mostly) analog cybernetic logic. Formalization of this logic should offer greater engineering control of design. In particular, the design language includes springs and pulleys, and no one has yet deeply interpreted the relations of these elements.

- Helical springs do offer long-lasting precision elastic force compared to elastomer bungees, but have an increased risk of fouling, so some detail innovation is needed. To avoid snagging, its possible that a proper bridle spring in low tension should be open-coiled rather than pinched shut, or that a tube covering is needed, particularly for grounded states of self-relaunch. This is an open area of study, since only a few cases of spring use are known.

- An ancient but poorly characterized design dynamic is separate wave-functions of LE and TE. The trick is for the LE to have higher inherent oscillation frequencies than the TE, so a LE luff recovers before the TE even responds. One sees this principle in kite LE hummers and canard aircraft.

- The hope remains open that perfected pilot kites will someday seem to fly themselves intelligently by suitable passive-active design (no electro-mechancial digital control). We are halfway there, and thats already amazing.

Congratulations to SkySails for ongoing development of parafoil ship kites.

The University of Hanover, officially the Gottfried Wilhelm Leibniz Universität Hannover, short Leibniz University Hannover, is a public university located in Hannover, Germany..

Thanks to Pierre Benhaiem for a link to a paper: 

Its only a matter of time before multi-tether PTOs are tested at large scale. The emergence of KPS and recovery of SkySails have put the soft kite strongly back into the mix of lead AWES contenders.

This paper is a fine contribution to tri-tether art. Thanks Pierre.

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Attachments :

Attachments :

Some further notes-

- Helpful addition of paper to tri-tether concept prior art exists in details of a novel differential transmission at the groundgen. The paper also compliments KiteLab and kPower demo work, creating some cross-validation.

- "Trajectory Surface" usage is a contribution to AWES dynamics nomenclature, extending the meaning of Kite Window while contrasting against Reeling architectures without fixed trajectory surfaces.

- KPS ground-station can in principle be used to demo concept at utility scale, by rigging a single power kite to three anchors (groundstation anchor-point and two pulley-anchor-points). SkySails could also rig a tri-tether demo by adding peripheral mechanical hardware. Collaboration of the new paper's authors, KPS, SkySails, and kPower would cover the IP bases across "all-modes". kPower also offers pilot-kite-based passive control expertise (with active control reserved for mode-transitions and exception-handling).

Sent today to the RHRK SciComp Team at TU Kaiserslautern, AWE's latest new player-

Hi Max, Ruby, and Nicolas,

Thanks again for your fine paper, which I continue to reread for new insights. Here is a quick summary of Open AWE work. Introducing Joe Faust here, the master-archivist of AWE references, and also a hang glider pioneer and flight visionary. It will take some time to share related work; all open-source, but widely scattered. SkySails of Hamburg is our closest DE partner, ready to pragmatically adopt whatever AWES topology emerges as optimal, based on ship-kite parafoils similar to the paragliders you use as unit-cases. I also have worked on ship-kites, via KiteShip, and there is a French ship-kite Airbus spinoff, and also a Boeing MOU via SkyMill. Our top mentor was the late great Dutch astronaut, Wubbo Ockels, who just before his death shared newly envisioned large multi-kite array concepts far beyond venture player down-selected architectures. Cristine Archer is also a major inspiration to us all, motivating thinking of the whole upper-wind resource in direct relation to global demand.

3r architecture is lately identified as a basic unit-cell in far larger lattice array concepts. ~1000m2 is seen as a current practical limit on soft kite size based on ground handling constraints. The Megafly parafoil cargo parachute is an existing case. Utility generators at GW scale therefore will require hundreds of unit-kites, but these can be latticed into a novel megascale metamaterial, with coherently phased wind-matched load-matched motions applied at the generator shaft. A top lifter iso layer is seen as natural to support an iso power-harvesting layer, with a surface cableway infrastructure aggregating forces to the generator. It is possible in principle to convert fossil fueled legacy plants to hybrids, or even produce planetary-scale lattices, rated in TW, capable of transfer bountiful kinetic energy over large distances, from best resource wind to populations.

In earlier years, our primitive kites revealed themselves as 6D aeroelastic spring-mass oscillators with chaotic statistics. Chaos is tamed by interconnection aloft, and long-range order created. Classic kite trains develop coherent phase-correlated lattice waves, but were stabilizer-damped to avoid excess power. We came to see the kite and arrays in wave-function terms, and passive tunable control as pilot-wave based (Bohmian mechanics). An early thermodynamic puzzle was how a 2MW rated ship-kite polymer tether remains cool, as a force super-conductance case. It turned out that phonon physics of second-sound applied. Debye temperature and Gibbs free energy apply. Empty sky freespace was seen as a topological insulator, with tensioned kite tethers acting as anyon (edge-based) phonon superconductors. It seems all that is required to apply QM logic is to assign kite characteristic-dimension and -frequency, as a Planckian natural-unit approach, instead of Planck Constant's microscopic quantum of action. Even entanglement emerges in obvious correlations between each end of a tensioned line (If not, the corresponding kite demos somehow still work).

Over tens-of-thousands of AWES Forum messages, misc. heuristic principles emerged in our loose world-wide test-oriented circle, that other venture-insider circles ignore. For example, power-to-mass is our primary figure-of-merit for a power kite (not L/D, sweep, etc.) while most teams load on high parasitic mass of non-power elements. We are the pure "rag-and-string" "low complexity" school. Another insight often overlooked is that while a kite may be scaled up, at a given altitude, most probable wind is constant. Then there is the complex advantage of low- wing-loading, where even an "ugly" wing with many tethers can achieve fairly high L/D. We have experimentally validated many high value ideas at elite kite festivals, like persistent flight by 3r circle-towing. While we make small-scale AWE in many forms work wherever there is wind, there is not any known large market. We see AWE's proper starting market as pioneering research toward the largest possible solutions. Small AWES solutions are natural spin-offs for humanitarian and remote applications.

What has been missed in AWE is comprehensive numerical metanalysis over all architectures, to rigorously predict probable winners. Too much effort has been wasted numerically analyzing ad hoc pet architectures in isolation. With the formidable insight evident in the paper, RHRK, may perhaps first predict just how AWE will finally succeed. Your concept of the "trajectory surface" usefully extends how the "kite window" is interpreted in AWE. Your differential transmission adds to ground-station art. Wishing for many more essential contributions to AWE from RHRK.

Please feel free to request anything that the "Open AWE" community can provide. Looking forward to amazing progress by all of us,

dave


Joe's note-