Messages in AirborneWindEnergy group.                           AWES10662to10711 Page 110 of 440.
Group: AirborneWindEnergy Message: 10662 From: Pierre BENHAIEM Date: 11/23/2013
Subject: Re: Looping Parafoil under a pilot kite

Group: AirborneWindEnergy Message: 10663 From: joe_f_90032 Date: 11/23/2013
Subject: B2B Matchmaking AWE Game

Group: AirborneWindEnergy Message: 10664 From: joe_f_90032 Date: 11/23/2013
Subject: Re: B2B Matchmaking AWE Game

Group: AirborneWindEnergy Message: 10665 From: dave santos Date: 11/23/2013
Subject: Two "KiteMills" (Disambiguation)

Group: AirborneWindEnergy Message: 10666 From: dave santos Date: 11/23/2013
Subject: Embedded Ram-Air Air-Beams for Mothra-Megascaling

Group: AirborneWindEnergy Message: 10667 From: joe_f_90032 Date: 11/23/2013
Subject: Re: Two "KiteMills" (Disambiguation)

Group: AirborneWindEnergy Message: 10668 From: Baptiste Labat Date: 11/24/2013
Subject: Re: Two "KiteMills" (Disambiguation)

Group: AirborneWindEnergy Message: 10669 From: Baptiste Labat Date: 11/24/2013
Subject: TU Delft Simulator

Group: AirborneWindEnergy Message: 10670 From: Baptiste Labat Date: 11/24/2013
Subject: Re: TU Delft Simulator

Group: AirborneWindEnergy Message: 10671 From: joe_f_90032 Date: 11/24/2013
Subject: Re: robokite: open source kite control software repository and proje

Group: AirborneWindEnergy Message: 10672 From: roderickjosephread Date: 11/25/2013
Subject: Re: Embedded Ram-Air Air-Beams for Mothra-Megascaling

Group: AirborneWindEnergy Message: 10673 From: joe_f_90032 Date: 11/25/2013
Subject: God spoke to Andrew Beattie in 1993

Group: AirborneWindEnergy Message: 10674 From: roderickjosephread Date: 11/25/2013
Subject: Re: Geoengineering with Megascale GeoFlow-Deflectors

Group: AirborneWindEnergy Message: 10675 From: dave santos Date: 11/25/2013
Subject: Re: Embedded Ram-Air Air-Beams for Mothra-Megascaling

Group: AirborneWindEnergy Message: 10676 From: dave santos Date: 11/25/2013
Subject: 1967 Everett Parawing ahead of its time...

Group: AirborneWindEnergy Message: 10677 From: dave santos Date: 11/25/2013
Subject: Titan Aerospace "Atmosat"

Group: AirborneWindEnergy Message: 10678 From: dave santos Date: 11/25/2013
Subject: Eccentric UK AWE Startup (New Wave Energy)

Group: AirborneWindEnergy Message: 10679 From: joe_f_90032 Date: 11/26/2013
Subject: Using mined power to move six bodies across the Atlantic

Group: AirborneWindEnergy Message: 10680 From: joe_f_90032 Date: 11/26/2013
Subject: Re: Geoengineering with Megascale GeoFlow-Deflectors

Group: AirborneWindEnergy Message: 10681 From: joe_f_90032 Date: 11/27/2013
Subject: Re: Titan Aerospace "Atmosat"

Group: AirborneWindEnergy Message: 10682 From: joe_f_90032 Date: 11/28/2013
Subject: Re: Titan Aerospace "Atmosat"

Group: AirborneWindEnergy Message: 10683 From: dave santos Date: 11/29/2013
Subject: Kite Line-Set and Quiver Life-Cycle (Update and Review)

Group: AirborneWindEnergy Message: 10684 From: dave santos Date: 11/30/2013
Subject: Kite Atmosats (Katmosat)

Group: AirborneWindEnergy Message: 10685 From: dave santos Date: 11/30/2013
Subject: Responding to Barnard on AWES Icing Hazard

Group: AirborneWindEnergy Message: 10686 From: dave santos Date: 11/30/2013
Subject: A Family AWE Business (Polar Kite-Ski Expeditions)

Group: AirborneWindEnergy Message: 10687 From: dave santos Date: 11/30/2013
Subject: Morphing WingSail Concept ( active vacuum-bagged foam beads)

Group: AirborneWindEnergy Message: 10688 From: dave santos Date: 11/30/2013
Subject: EnerKite's rotating-launch ambition for a 2017 MW-scale AWES

Group: AirborneWindEnergy Message: 10689 From: dave santos Date: 12/1/2013
Subject: NTS promoting AWE railway as tow-launching means

Group: AirborneWindEnergy Message: 10690 From: dave santos Date: 12/2/2013
Subject: New Method for Hotswapping and Cascade-Launch

Group: AirborneWindEnergy Message: 10691 From: dave santos Date: 12/2/2013
Subject: Flemish AWE coverage (esp. of Leuven and Berlin)

Group: AirborneWindEnergy Message: 10692 From: dave santos Date: 12/2/2013
Subject: The Science of Megascale Oscillation (review and update)

Group: AirborneWindEnergy Message: 10693 From: Baptiste Labat Date: 12/3/2013
Subject: Re: The Science of Megascale Oscillation (review and update)

Group: AirborneWindEnergy Message: 10694 From: Rod Read Date: 12/3/2013
Subject: Re: The Science of Megascale Oscillation (review and update)

Group: AirborneWindEnergy Message: 10695 From: dave santos Date: 12/3/2013
Subject: Re: The Science of Megascale Oscillation (review and update)

Group: AirborneWindEnergy Message: 10696 From: joe_f_90032 Date: 12/3/2013
Subject: Group management note

Group: AirborneWindEnergy Message: 10697 From: joe_f_90032 Date: 12/3/2013
Subject: Floyd Arntz

Group: AirborneWindEnergy Message: 10698 From: joe_f_90032 Date: 12/3/2013
Subject: Re: Kitellite and KiteFi Trademark Notice

Group: AirborneWindEnergy Message: 10699 From: santos137 Date: 12/4/2013
Subject: Re: The Science of Megascale Oscillation (review and update)

Group: AirborneWindEnergy Message: 10700 From: dougselsam Date: 12/5/2013
Subject: Re: The Science of Megascale Oscillation (review and update)

Group: AirborneWindEnergy Message: 10701 From: joe_f_90032 Date: 12/5/2013
Subject: Re, Reynolds number

Group: AirborneWindEnergy Message: 10702 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number

Group: AirborneWindEnergy Message: 10703 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number

Group: AirborneWindEnergy Message: 10704 From: dougselsam Date: 12/5/2013
Subject: Re: Re, Reynolds number

Group: AirborneWindEnergy Message: 10705 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number

Group: AirborneWindEnergy Message: 10706 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number

Group: AirborneWindEnergy Message: 10707 From: dave santos Date: 12/6/2013
Subject: Re: The Science of Megascale Oscillation (review and update)

Group: AirborneWindEnergy Message: 10708 From: dave santos Date: 12/6/2013
Subject: More AWE Encampment Tests (SkyBow, Race Kite, and FAA Conspicuity)

Group: AirborneWindEnergy Message: 10709 From: dougselsam Date: 12/6/2013
Subject: Re: More AWE Encampment Tests (SkyBow, Race Kite, and FAA Conspicuit

Group: AirborneWindEnergy Message: 10710 From: dougselsam Date: 12/6/2013
Subject: Re: Re, Reynolds number

Group: AirborneWindEnergy Message: 10711 From: dougselsam Date: 12/6/2013
Subject: Re: Re, Reynolds number



Group: AirborneWindEnergy Message: 10662 From: Pierre BENHAIEM Date: 11/23/2013
Subject: Re: Looping Parafoil under a pilot kite


JoeF and Ed,

 

This AWES is a real progress by using self-crosswind flying (it is the sense of my precedent post).A manual pilote can secure launching and launding among his other activities. Another possible use as safety device (for some sort of areas where conventional turbine is not implementable, good winds being above trees for example) where automatic launching and landing are not so important.

 

PierreB
Group: AirborneWindEnergy Message: 10663 From: joe_f_90032 Date: 11/23/2013
Subject: B2B Matchmaking AWE Game
Group: AirborneWindEnergy Message: 10664 From: joe_f_90032 Date: 11/23/2013
Subject: Re: B2B Matchmaking AWE Game
Group: AirborneWindEnergy Message: 10665 From: dave santos Date: 11/23/2013
Subject: Two "KiteMills" (Disambiguation)
The long list of known AWE teams continues to grow, as well as instances of duplicate names; this time  "kitemill".


2010 "Kitemill" l'Ecole Central de Lille, France: Student project. There is a pattern of promising student projects ending short of full success, but we expect some of these kids to continue upward-



"Kitemill", the mysterious Norwegian startup seeking engineers. Only a stem-like launching stand concept is known-
Group: AirborneWindEnergy Message: 10666 From: dave santos Date: 11/23/2013
Subject: Embedded Ram-Air Air-Beams for Mothra-Megascaling
At 1/40 scale, Motha1 (300m2) was able to use a rigid central spar (bamboo truss) for stability and control. Only true soft-kites megascale, so giant future Mothras require a soft solution to maintaining a luff-resistant LE. A promising "classic" solution is to create a large ram-air air-beam embedded in the LE, patterned after sled-kite or parafoil cells. Then the SS kixels can transiently luff and recover from turbulence at high-frequency, before the low-freq airbeam can destabilize. Such air-beams should easily scale to with large kixel fields between the airbeams. The airbeams could also be valved, and double as enclosed areotectural spaces.

CC BY NC SA
Group: AirborneWindEnergy Message: 10667 From: joe_f_90032 Date: 11/23/2013
Subject: Re: Two "KiteMills" (Disambiguation)

http://www.energykitesystems.net/KiteMill/index.html

News is invited. 


The distinct "Projet Kitemill" of 2010: 

http://www.energykitesystems.net/ProjetKitemill/index.html  where is a clip showing the list of participants including helpers and consultants. 

News is invited. 
Group: AirborneWindEnergy Message: 10668 From: Baptiste Labat Date: 11/24/2013
Subject: Re: Two "KiteMills" (Disambiguation)
I have made a few researches on the people involved in Kitemill project from Ecole Centrale de Lille. They have now graduated and work in several companies without relation to AWE. 
I have sent an email to Jean-Pierre Richard to have news.

++
Baptiste
http://robokite.blogspot.fr/
https://github.com/baptistelabat/robokite
Group: AirborneWindEnergy Message: 10669 From: Baptiste Labat Date: 11/24/2013
Subject: TU Delft Simulator
Hi,

For your information, TU Delft is releasing one of its kite simulators (thanks to the work of Uwe Fechner) under LGPL license.

The code is here https://bitbucket.org/ufechner/freekitesim

You can find some screenshot on robokite blog (still in french, any participation welcomed !)
http://robokite.blogspot.fr/2013/11/tu-delft-simulateur-uwe-fechner.html

I think this is a great step to help improving simulation and kite control systems (the simulator can be linked even to proprietary software, and so can be used as a benchmark platform).

The installation is not so easy so far, but this will improve with a growing number of users.


Enjoy,

Baptiste
Group: AirborneWindEnergy Message: 10670 From: Baptiste Labat Date: 11/24/2013
Subject: Re: TU Delft Simulator
An open discussion group on the simulator subject was created today https://groups.google.com/forum/?hl=fr#!forum/free-kitesim
Feel free to join!

++
Baptiste
Group: AirborneWindEnergy Message: 10671 From: joe_f_90032 Date: 11/24/2013
Subject: Re: robokite: open source kite control software repository and proje

 

RoboKite by Baptiste Labat       
folder in EnergyKiteSystems
Group: AirborneWindEnergy Message: 10672 From: roderickjosephread Date: 11/25/2013
Subject: Re: Embedded Ram-Air Air-Beams for Mothra-Megascaling

http://2e5.com/kite/npwc/foilnose3/

Some excellent experimentation notes on single skin and ram air
Group: AirborneWindEnergy Message: 10673 From: joe_f_90032 Date: 11/25/2013
Subject: God spoke to Andrew Beattie in 1993
Group: AirborneWindEnergy Message: 10674 From: roderickjosephread Date: 11/25/2013
Subject: Re: Geoengineering with Megascale GeoFlow-Deflectors

AWE as an architecture for tidying oceanic gyres is a fantastic concept.


We want a large kite to dredge plastics in a dragnet without being taken by ocean currents.


I'd assume an arch going downwind with feet being held spread out by a suitably opposing water foils (as per dragnet opener). 

Current acting on the net needs to impart less drag than the kite. So the net will probably be small and porous compared to kite.

Net would probably also be suspended from kite bridling instead of feet and water foils. so as to avoid excess line drag through plastic debris.


you mentioned that

As a default, the deflector should self-kill in a fail-soft mode

In this case

It may also help if when the bag is "full" it is drawstrung / and or / the kite autozeniths or auto kills.


Is a net bag of plastic rubbish going to cause more harm than free floating plastic as the contents are now forced to smash into and further degrade each other? should the bag be recovered, beached or sunk?


 
Group: AirborneWindEnergy Message: 10675 From: dave santos Date: 11/25/2013
Subject: Re: Embedded Ram-Air Air-Beams for Mothra-Megascaling
Rod,

BillR has been on our radar a long time (via NPW and Dave Culp's OL circles). He has done great soft-kite work, even developing an "NPWC" design that is a cross between an NPW and OL (kPower even has a small NPWC in its quiver). PeterL also did "foil-nose" soft kites around 2008 (it was a hot topic).

The major differences of the current idea are: 1) the "new" airbeams are isolated between untailored SS (kixel) sections to reduce weight and construction labor (a single central beam can suffice to control an entire arch like Mothra1); 2) the new megascale airbeams extend all the way to the TE, for maximal "harmonic" stability (damping high-freq luff in the bud).

This latest AWES arch idea represents the ongoing evolution of megascale soft kites since BillR's known experiments. It would be wonderful to involve Bill (Cc:ed) in the new experiments, to perhaps sooner find the ultimate pattern for giant arches (fractal-scaled isolated ribs?),

daveS

PS My old-school SS trick was to ventilate the LE with small sawtooth or hole vents to recover from luff initiation faster, and also set up "turbulation" vortices over the top surface. We might see these old tricks in play again, in definitive testing :)


On Monday, November 25, 2013 2:08 AM, "rod.read@gmail.com" <rod.read@gmail.com
Group: AirborneWindEnergy Message: 10676 From: dave santos Date: 11/25/2013
Subject: 1967 Everett Parawing ahead of its time...
An old gem from BillRa's pages; Everett's foil-nose NPW is an early synthesis of Jalbert and Barrish, filling a big gap in the soft-kite price-performance spectrum-


The prototypes would still be flyable, if they can be found.
Group: AirborneWindEnergy Message: 10677 From: dave santos Date: 11/25/2013
Subject: Titan Aerospace "Atmosat"
trending: large persistent-flight solar-aircraft
Group: AirborneWindEnergy Message: 10678 From: dave santos Date: 11/25/2013
Subject: Eccentric UK AWE Startup (New Wave Energy)

Lets hope they learn super fast or live really long. This is the low-wingloading version of Titan's application-space, and would be plausible if the structure was purely tensile, using line for power "beams", etc., etc.. Charmingly childlike, with a deep idea or two-
Group: AirborneWindEnergy Message: 10679 From: joe_f_90032 Date: 11/26/2013
Subject: Using mined power to move six bodies across the Atlantic
Traction: 
Using mined power to move six bodies across the Atlantic:
Group: AirborneWindEnergy Message: 10680 From: joe_f_90032 Date: 11/26/2013
Subject: Re: Geoengineering with Megascale GeoFlow-Deflectors

Processing plant?  Continuous processing (compacting, shaping, melting, burning, chemically changing, ..?) perhaps to make things: hydrogen, wings, hulls. floats, bulk solids for later further processing?
Group: AirborneWindEnergy Message: 10681 From: joe_f_90032 Date: 11/27/2013
Subject: Re: Titan Aerospace "Atmosat"
Atmostat 
"An atmosat is an artificial body maintaining a persistent state within the atmosphere of the earth or another planet in order to collect information for communication."   Think of Kitesat as an atmostat.
Group: AirborneWindEnergy Message: 10682 From: joe_f_90032 Date: 11/28/2013
Subject: Re: Titan Aerospace "Atmosat"

...Maybe in 2005  

http://www.dept.aoe.vt.edu/~cdhall/courses/aoe4065/RFP-Titan2005.pdf

Request for Proposal: A Self-Sustaining System for Global Terrain Exploration and Environmental Sampling on Titan "NASA is considering a new system concept for exploring Titan. The system is self-sustaining, extracting energy from the planetary boundary layer for both energy renewal and ef- ficient locomotion. The system comprises three components:

1) A fleet of rechargeable, autonomous, buoyancy driven gliders, actuated through internal shape control. 

2) A tethered, buoyant vehicle to harvest wind energy in the upper planetary boundary layer. "

Group: AirborneWindEnergy Message: 10683 From: dave santos Date: 11/29/2013
Subject: Kite Line-Set and Quiver Life-Cycle (Update and Review)
Its well established in kite sports that a large quiver of kites in a broad range of sizes, and various line-sets, are required to optimally match varied wind speeds. AWES developers typically already use such quivers as well.

In kite-sports, the desired max human loading factor remains more-or-less constant, as the max structural demand on the lines. To a lesser extent, a quiver of lines of varied lengths (and ages) is employed according to conditions, but the loads remain closely "human-rated". This operational pattern works in our favor for AWE, in that a quiver of kites has a cummulatve life-cycle far greater than a single kite, so factors like UV and friction are far less of a constraint on acceptable life-cycle. Kite suppliers also discount quiver purchases.

The engineering take-away is that an optimal AWES system based on soft kites requires a quiver and the life-cycle rating will be based on the quiver life. The optimal quiver will cover "most probable wind" more closely (more kites in the middle range). Overlapping flight envelopes ensure that if a single kite is out of commission for repair, an adjacent rated kite can cover the gap. As kites and lines age, they should be systematically derated. A rule-of-thumb (heuristic) is that new kites* and old kites are best kept packed in gusty increasing winds, by using older but fully sound wings. There are many more quiver life-cycle refinements possible, like seasonal quivers to match UV and wind variations. A major economic aspect is that kites continue to improve and costs continue to drop, so there is predictably a better quiver to come for any long-lived AWES. 

Line-set quivers will be simpler to specify than kites, within a far narrower range of sizes. The tricky part is to account for creep effects (by location rotation and retuning) where lengths will vary by loadtime, with working strength and drag performance initially growing then tapering, and with constant close inspection for damage required. A knotted, nicked, or scuffed line will fail suddenly, with little warning, compared to a kite's rip-stop capability.

A recent (AWE Encampment) finding is that AWES use of sport kites easily involves much higher loadings than a human can take. The kites seem to take this in stride, but those that are better constructed are favored (some brands and models are clearly more robust, for a bit of extra cost). 


* Just as racing sailors guard new sails from being over-stretched too soon.
Group: AirborneWindEnergy Message: 10684 From: dave santos Date: 11/30/2013
Subject: Kite Atmosats (Katmosat)
"Atmosat" is clearly an old idea (since at least 1975) with many variations, like balloons and solar e-flight. The NASA planetary science view often involves tethered hybrid kites. Now that we know reverse-pumping is practical*, "katmosats" are a leading atmosat contender, in terms of cost by capability, for many small applications. Next Gen will offer solutions for long roaming tethers to share crowded airspace, so major apps could follow the small.


CC IP notice- "Katmosat" is hereby reserved as a TM for the Kite Power Cooperative to administer


* by working step-towing variations from gliding sports, academia, and AWES R&D
Group: AirborneWindEnergy Message: 10685 From: dave santos Date: 11/30/2013
Subject: Responding to Barnard on AWES Icing Hazard
Barnard blogged: "Winter conditions have so far been ignored by public documentation of the majority of reasonably worked out generation schemes. Icing of flying devices is a serious maintenance and safety concern, and approaches to solving icing for airplanes are significant maintenance and operations expenses by themselves. Further, high altitude devices will often or even usually be flying in below zero temperatures so icing and frost build up will need to be addressed."


kPower reply-

The currently most popular AWES basis, soft kites, naturally shed ice as it forms, exactly as the rubber boots on vintage aircraft wings shed ice by substrate flexing (KiteLab Illwaco 2009). Aircraft are hardly ever equipped with boots these days, owing to mature understanding and precise prediction of icing conditions.

Aviation icing conditions only occur at the thin interface of freezing-thawing, and so are easily avoided by reference to modern weather data. Pilots simply fly thru this boundary promptly to avoid ice build-up (with minor icing then melting or sublimating).  Rigid wing AWES can simply suspend operation when icing conditions exist at design altitude (an infrequent event in most locations). 

Sub-zero winter conditions are thus quite flyable from the icing-hazard perspective, since there is no free water to form new ice.
Group: AirborneWindEnergy Message: 10686 From: dave santos Date: 11/30/2013
Subject: A Family AWE Business (Polar Kite-Ski Expeditions)
The simple reason AWE developers do not live from their prototypes like pioneers, as some naive critics demand, is that electrical grids are so ubiquitous that the stunt would be merely symbolic. Our real race is to engineer ever better designs on far larger scales, to power giant electrical grids. Let us finish the big job before we retire to off-grid kite homesteads.

Some folks already live for extended periods by kite power (for transport), like this amazing family of polar kite skiers, eager to teach just how its done-


They have set many polar kiting records, even covering over 100mi in a single day, fully loaded. Given a well-proven kite transportation foundation, the natural next-step is to attach a generator wheel to the kite-towed sled, to charge satphones, lights, etc.. Also expect the kite-pilot to end up riding on the sled, with skis as an adjunct.
Group: AirborneWindEnergy Message: 10687 From: dave santos Date: 11/30/2013
Subject: Morphing WingSail Concept ( active vacuum-bagged foam beads)
A membrane bag in the general shape of a wing, filled with foam beads, can be loosely shaped into a suitable airfoil and then fixed (drawn taught) by pulling a partial vacuum. A partially embedded spar would comprise a structural stiffening spine to step as a mast or use as a wing-root.

The shaping phase could be as basic as hand forming by trowelling strokes or simple molding, for varied complex profiles to test or match to conditions. Partial vacuum would allow sensitive trim-plasticity, before "locking" the form. The shaping process is reversible by releasing the vacuum. Many tricks can be devised to extend the basic capabilities, including live-morphing during operation (like tacking the sail camber to port or starboard). Internal airbags could actuate trim inputs.

Wingsails on this principle could be light and robust. Most mishaps would be fully corrected by just patching holes and/or resetting the form.


CC BY NC SA
Group: AirborneWindEnergy Message: 10688 From: dave santos Date: 11/30/2013
Subject: EnerKite's rotating-launch ambition for a 2017 MW-scale AWES

EnerKite proposes to field a MW scale AWES unit by 2017, with rotating launch akin to the Leuven architecture. A novel flying-wing is seemingly shown in recent concept graphics, consistent with the fact that the current parafoil choice would tend to lack the mass and high L/D to launch so. The team has done well so far, but the emerging scaling strategy presents many open questions.

This marketing claim really needs comparative supporting data to be credible- 

"EnerKite leads the field of dynamic airborne wind energy controls and efficient kite wings..."
Group: AirborneWindEnergy Message: 10689 From: dave santos Date: 12/1/2013
Subject: NTS promoting AWE railway as tow-launching means

Automated launching is one of the major challenges for AWES. NTS has identified their railway concept as advantaged in potentially towing kites up into flyable wind, which helps justify the high added capital cost of a track (compared to trackless AWES). Towing is only a partial solution, however, since automated kite ground-handling is the harder problem, and they haven't disclosed that solution. 

NTS's capital-intensive elevated track idea seems to be giving way to a cheaper ground track with tunnel access for agriculture within the loop. A ground track, however, permanently removes considerable land from dual agricultural uses, so its a trade between high capital-cost and lower long-term value. The sum of such "minor" details ultimately decide whether a gamble of an early architectural down-select pays off. If fixed kite cells within a kite farm convincingly solve launching, and operate more flexibly and robustly at efficiencies comparable to a track, then the capital-intensive track idea may be a clear non-starter. Expect to see a circus-worth of novel launch-land demos by competitors in 2014.

NTS has extended its web content. They are now seeking 50k EU in crowd-funding for the circular track prototype, which suggests that normal venture capital in larger chunks has tightened for them-


German green biz journal coverage, -
Group: AirborneWindEnergy Message: 10690 From: dave santos Date: 12/2/2013
Subject: New Method for Hotswapping and Cascade-Launch

A kite farm must be able to perform early relaunch into upper good wind through a surface calm layer. To compete by max capacity-factor, every AWES R&D team must choose how to meet this requirement. Proposed solutions range from high-complexity E-VTOL to low-complexity tricks like the following:

First winch-tow a small pilot-lifter kite into the good wind. The new trick is a short tether on the pilot-kite that ends with a pulley, which pulls up a double-line passed thru the pulley. This double line works as a sort of elevator cable to hoist aloft larger kites into the good wind. It is best flown as a tall crosswind arch to best avoid interference of the rising and descending sides. 

A stopper-ball on the loop-line jams at the pilot-kite pulley such that the initiating kite is then drawn back down by the loop. A second larger kite on its own pulley is hoisted by the loop. It is restrained from interfering with the prior kite by a second stopper-ball. At zenith the second stopper-ball passively releases to continue back down the loop. A third stopper-ball in the loop then jams in the second pulley to draw the second kite down, to again make room at zenith for a third, larger, kite; and so on, until enough lift exists for a mass cascade-launch of the large-scale kite array (ie. a Mothra). All the while, the kite line in the launching loop also scales up.

Cascade-launch prior-art (KiteLab PDX, 2007) enabled small kites to lift progressively larger kites in a bang-bang-bang or manual sequence. While this worked well in surface wind, it did not solve the common case of launching through a thick calm layer, and the pilot-stage was not ideally withdrawn as winds increased. This new solution presented here is conceptually related to Cody's cascaded kite-train system, with stoppers and rings, from the "Golden Age of Kites" over a century ago.

Many variations on this loop/pulley/stopper-ball method allow for hotswapping kites and lines to match conditions, and to perform simple kite-array control logic. Suitable pulleys and stopper-balls are sold by kite sport  and sailing suppliers.

CC BY NC SA
Group: AirborneWindEnergy Message: 10691 From: dave santos Date: 12/2/2013
Subject: Flemish AWE coverage (esp. of Leuven and Berlin)

Congratulations to Reinhart for a great job presenting AWE in this clean energy documentary; min-sec 41:20 is where the AWE part starts-


Highlights include Reinhart hopping a Flysurfer, Leuven's carousel testbed, and the Berlin conference flying event. See lots of our friends caught on video.
Group: AirborneWindEnergy Message: 10692 From: dave santos Date: 12/2/2013
Subject: The Science of Megascale Oscillation (review and update)
ZhangLab (NYU) has long done formal models and experiments with small-scale flapping wings. In revisiting this work, we find confirmation that there is a clear Reynolds number (Re) threshold for inherent oscillation. All flags flap, given enough wind. We are on pretty solid ground here, and even ready synchrony mechanisms are well established, so what about megascale operation?

Megascale soft wingmills for AWE will remain a somewhat open question until actually tested, but our theoretic understanding grows year-by-year. The question has been; will giant soft wingmills really flap; or is there an overlooked scaling effect to inhibit flapping? Perhaps we are now ready to correctly predict they will flap, based on facts available to us.

For megascale wingmills, the large characteristic-dimension only boosts Re, thus:

     Re = vL/v = (velocity*Length)/velocity = (5m/s*1km)/ 5m/s = 1000

Re1000 is well above Zhang's flapping initiation threshold (even accounting for a reasonable Cp, which raises the threshold moderately). Our "buildable" km-scale wingmill therefore seem suited for strong oscillation, even down to fairly low wind velocity, especially since we know how to destabilize a wing, then lead it into "forced" oscillation. Mothra showed natural (weak non-optimal) oscillation in side-wind, but was intended for max stability. 

For these reasons, high confidence in megascale oscillation seems justified. Regarding a related mystery- As Peter Lynn rued, for AWE use, a quirk of the NPW is to sometimes choose to fly backwards. ZhangLab's research explains this effect as a "spontaneous symmetry-breaking bifurcation", in dynamical-speak. We need only somehow bifurcate deterministically.

This ZhangLab page, and linked papers, contain supporting science-
Group: AirborneWindEnergy Message: 10693 From: Baptiste Labat Date: 12/3/2013
Subject: Re: The Science of Megascale Oscillation (review and update)
Hi, thanks for sharing your reflexions

 I think you have something wrong in your formula.

The Reynolds Number is v*L/ν where ν (Greek letter nu) is the kinematic viscosity which is around 1.8e-5 for dry air.
The characteristic length will the megascale cord, not span (but some tri-dimensional modes are possible too).
As a results the Reynolds number will be much higher (1000 is very viscuous)

Oscillations will arrive when fluid dynamics inherent frequency (see Strouhal frequency or number) is close to structural frequency (which depends on mass and added mass and stiffness of the structure).

++
Baptiste
Group: AirborneWindEnergy Message: 10694 From: Rod Read Date: 12/3/2013
Subject: Re: The Science of Megascale Oscillation (review and update)
The models of a "Mothra" arch kite is constrained by a loadpath and can't be compared to the flag or flapping wing models.
but
Individual kixels may behave similarly to flags.
I think the Zhang literature only describes synchronisation of flags where they are aligned stacked through the flow instead of lined side to side.

Where the trailing edge corner of a kixel attaches to a loadpath ... the trailing edge shape, the connection web shape, the elastic strength of the connector will all have implications for vortex shedding drag. As per standard wing dynamics.

However ... driving units set like flags (see flipwings) hoisted under a kite will flip side to side, (like buzzing harmonic tensioned vertical flags (I say buzzing because I live in  high wind e.g. high Hz))

Yet again though I would think more power can be derived from the larger amplitude oscillations of tacking jib type vertical sails,  where tension is applied down the trailing edge smoothing flow. fast rigid shapes.

Rod Read

Windswept and Interesting Limited
15a Aiginis
Isle of Lewis
HS2 0PB

07899057227
01851 870878
Group: AirborneWindEnergy Message: 10695 From: dave santos Date: 12/3/2013
Subject: Re: The Science of Megascale Oscillation (review and update)
Rod wrote: "The models of a "Mothra" arch kite is constrained by a loadpath and can't be compared to the flag or flapping wing models."


Reply: All wings will flap, to the extent they are aeroelastic. A flapping flag is a crude but real loadpath device; its reinforced leading edge corresponds to Mothra's A-line. Think of a flapping Mothra (variant) as a horizontal flapping flag (although exact flapping modes can vary).

Current flapping-arch models (KiteLab Austin) are working quite well, so expect to see video documentation soon. The goal is to develop a sort of passive flapping bird-kite held by its wingtips.





On Tuesday, December 3, 2013 4:32 AM, Rod Read <rod.read@gmail.com
Group: AirborneWindEnergy Message: 10696 From: joe_f_90032 Date: 12/3/2013
Subject: Group management note
All, 

   If you have posted a message and you do not see the message in the online run of messages, then please send me a note about the matter.    Also, it is recommended that one first compose messages so one has a master local copy of your composition; edit such and then post the message.  We do not want to lose your efforts!

Because the new "neo" arrangement, Yahoo is permitting massive amount of spam to show in the moderator's "pending" folder. Yahoo is not providing easy global "delete all". So, as of this week forward, moderator will not even be looking into the "pending" folder. The time cost to upload and then delete one-by-one will now be avoided; there is a chance that AWE matter will slide to automatic deletion; so keep original copy of your inputs.  Almost no AWE messages have been showing in "pending" folder. 

Thanks, 
   Moderator   JpF
Group: AirborneWindEnergy Message: 10697 From: joe_f_90032 Date: 12/3/2013
Subject: Floyd Arntz
Floyd Arntz


Open for discussion. 
Group: AirborneWindEnergy Message: 10698 From: joe_f_90032 Date: 12/3/2013
Subject: Re: Kitellite and KiteFi Trademark Notice
Group: AirborneWindEnergy Message: 10699 From: santos137 Date: 12/4/2013
Subject: Re: The Science of Megascale Oscillation (review and update)

Thanks Batiste, for catching my errors. 


In haste I forgot Kinematic Viscosity (Duh, and also overlooked the italic v on a small screen, and was puzzled at some impossible results). My other error was to confuse hydraulic diameter with span, somehow my habit has long been to choose the largest dimension for Re rather than chord; nor does simple chord ensure a correct exact result to our crude calculations. This is why I prefer empirical methodology, since full AWES prediction is still uncertain or even intractable for our best mathematicians.


At least the corrected formula result is even more optimistic that megascale flapping is inherent: it was lucky to err on the safe side :)


daveS



(List Management Note: Batiste's original reply never appeared in my mailer)
Group: AirborneWindEnergy Message: 10700 From: dougselsam Date: 12/5/2013
Subject: Re: The Science of Megascale Oscillation (review and update)
Only a real newbie would use span rather than chord to calculate Reynolds number.  Is that an example of your stated mastery of aviation?  Keep scrambling in your rambling.  It's mostly just a bunch of nonsense.  I noticed you recently declared an intent to bypass small systems as irrelevant, concentrating on big systems only.  That is the exact symptom I have described for years that allows "the good professor" (Crackpot) to be able to stay forever in the land of "if only we were allowed to do what we really want to" which "sounds good", like you know what you're talking about.  But if something is going to work, it can work at a small scale.  Avoiding small systems is merely avoiding the necessity to ever prove anything you say.  The real reason the good professor always adopts this policy is it allows him to keep talking about how smart he is, even while having little or no actual understanding of the art of wind energy.  It's all an act to impress those who don't know any better, that perpetuates a fantasy, but there's nothing behind it.
Group: AirborneWindEnergy Message: 10701 From: joe_f_90032 Date: 12/5/2013
Subject: Re, Reynolds number
Group: AirborneWindEnergy Message: 10702 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number

http://en.wikipedia.org/wiki/Viscosity

http://en.wikipedia.org/wiki/Density_of_air


Characteristic length for wings in kite systems?

       Most common: chord of wing involved.
Group: AirborneWindEnergy Message: 10703 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number
http://www.wfis.uni.lodz.pl/edu/Proposal/image009.gif

Rough comparison of flying things ... 

Quote from page:    http://www.wfis.uni.lodz.pl/edu/Proposal.htm

Figure 1-8 Variation of Reynolds numbers with speed across insects, micro-air vehicles, birds, Model airplanes, Human powered vehicles, aircraft, hang-gliders and lighter than air airships. Adapted from (Lissaman 1983). 
Group: AirborneWindEnergy Message: 10704 From: dougselsam Date: 12/5/2013
Subject: Re: Re, Reynolds number
Hi Joe:
Taken from your link labeled "Start":
The relevant section is:

Flow around airfoils

where it says:

Fluid dynamicists define the chord Reynolds number, R, like this: R = Vc / ν    Note: (keyword: chord)


So the relevant distance for an airfoil Reynolds number is chord.


In fluid mechanics class in college we learned Reynolds Number as Rho V D over Mu.


Anyway it was interesting a couple of years ago to see actual wind energy terminology used on this list, but acquiring a few items of terminology is a long way from understanding.  When we see the terminology misapplied, that tells us we are not up to speed yet.  Misapplying basic terminology is characteristic of not knowing what one is talking about.

:)

Group: AirborneWindEnergy Message: 10705 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number
Been a while, Doug! Welcome.  Snow, ski?
=================================

Though the chord is the most-used characteristic length, 
some studies have explored "span Reynolds number in special studies when a choice is made to take span as the characteristic length; dimensionless numbers based on span have received some attention.  https://www.irphe.fr/~eloy/PDF/JFM2013b.pdf




This note is not to be confused with such phrases as "quarter-span Reynolds number" where the chord at quarter-span station is the characteristic length in focus. 

It is the convention that "chord" is intended as the characteristic length, unless some other characteristic length is defined in a discussion.  Stations along the span have station-specific chord Reynolds numbers. Stations along the span of a wing: mid-span, tip, full-span, semi-span, specific exact station, ...     


Group: AirborneWindEnergy Message: 10706 From: joe_f_90032 Date: 12/5/2013
Subject: Re: Re, Reynolds number

 http://gram.eng.uci.edu/rangel/mae130a/osborne-reynolds.pdf 
Note on the History of the Reynolds Number by N. Rott, 1990.
Group: AirborneWindEnergy Message: 10707 From: dave santos Date: 12/6/2013
Subject: Re: The Science of Megascale Oscillation (review and update)
Hi Baptiste,

Thanks for pointing out the problem with my Re formula. It is the same to calculate Re from span as chord, as reciprocals, but the formula is still wrong (gives a Santos number). To neglect kinematic viscosity is my stupider error; the Greek v looked Latin on a small screen.

Please help us work out the question of inherent-flapping of giant wings, as there is a shortage of careful predictions. We have reviewed Stouhal number (freq simply lowers by dimension), but the general question includes scale onset and drop-out from dynamic-stability, rough power-factors, and so on.

TIA,

daveS


On Tuesday, December 3, 2013 6:01 AM, dave santos <santos137@yahoo.com
Group: AirborneWindEnergy Message: 10708 From: dave santos Date: 12/6/2013
Subject: More AWE Encampment Tests (SkyBow, Race Kite, and FAA Conspicuity)
Roy Meller's SkyBow is an amazing AWE demonstrator. Its confounding how this magical ribbon overturns almost everyone's ideas about soft kites, torsion transmission, load velocity, and so on. Its big and slow and small and fast, at the same time. The SkyBow kit was well designed and made by Roy himself. In a big wind, it writhes and moans like host of demons, which few would choose to live under (but might attract yuppie goth-punks). Consider the SkyBow as a surprise contender in AWE, deserving of more research (Roy's Jalbert Aerology Lab is in Kite Power Coop and kPower circles).

We flew a 250ft "Pro" model, and measured rpm peaks to 20k with a laser tach. The unit flew at 50 degrees or so elevation in a near gale for many hours without a fault (we doused ahead of rain, to protect the bearings). Sustainable torque, instantly able to burn skin, seemed good enough to draw 10W or so. This may not seem like much, but this wing is just a plain-sewn ribbon hardly an inch across, and rolls up very small. To tap a SkyBow will require the right little generator at each end, and may involve a clutch to the load, and some flywheel mass, or complex motor-gen control. We have a few clues about SkyBow physics. The lift is a blend of Magnus and a backward looping DS mode. Torque seems to be supported by an archimedes-screw effect at each "ear" of the arch. Yes, its a crosswind-arch, but a very extreme case that we hardly know yet.

Roy also made and sent us a small-scale FAA Conspicuity-Test parafoil (see photos by Roy). It has bits of original Jalbert Aerology Lab fabric, and has been flying the same polar-front gale as the SkyBow and Kayakite. We are taking visibility measurements in varied marginal conditions of gloom and fog, far exceeding FAA minimums in VFR conditions. One issue is that kites are not equally conspicuous from all angles, so a refined kite should emerge.

kPower obtained a wonderful 4m2 Pansh race kite (on sale for 99USD) to compare with ordinary power foils. The flying is much more active and proactive, but the surges are wonderfully monstrous. Such a wing can jump an adult in a mild breeze. Parafoil performance has continued to advance as prices have dropped. We have also been flying our smallest NPWs (.5,1,1.5 m2) in high winds, and they also amaze by power and speed.

The AWE Encampment is preparing for mini-AWEfest trials next, to power a wild party of music and lights by several small-scale AWES at once, to see what happens...
Group: AirborneWindEnergy Message: 10709 From: dougselsam Date: 12/6/2013
Subject: Re: More AWE Encampment Tests (SkyBow, Race Kite, and FAA Conspicuit
Roy Mueller sent us a Skybow to play with.
It was awfully nice of him to send, and quite an impressive science toy.
I took one to the unlimited class RC pylon races at nearby Rabbit dry lake bed, thinking the RC pilots would adopt skybows instead of pylons, but they turned out to have little interest in Skybow.  I was surprised.  You'd think people like that would be very attracted to such a cool flying thing.  Anyway I would like to help Roy promote this product in some way so that was why we brought one out to that RC airplane race.  I think it is super-cool.  It seems like all it needs is for someone to figure oiut something to DO with it!  But even with no other purpose than just flying it for fun, it is definitely very fun, and very interesting.  Amazing how things that work are often so simple.
With our high winds here we melted the plastic ends pretty quick, and I suggested double bearings to Roy, which he has since tried, and sent us some new handles.  We'll try them as soon as we get some wind.
It seems to operate ont he same principle as when you drop a strip of cardboard and it spins like a paddlewheel as it travels away from you at about a 1:1 glide ratio.  So far I did connect it to a little generator but the starting resistance torque of the generator prevented the Skybow from spinning.  I decided maybe if I wanted to get the full 10 Watts, it might need a clutch so the Skybow could spin up first and then engage the generator. Then again you could get 10 Watts pretty easily using a 1-foot diameter propeller.
Group: AirborneWindEnergy Message: 10710 From: dougselsam Date: 12/6/2013
Subject: Re: Re, Reynolds number
Hi Joe:
Yup I was skiing a couple hours ago, thanks 4 asking.  It was sunny and warm, as is usually the case here in the High Desert of Southern California, until right when I pulled into the parking lot at Mt. High.  I parked and got out to talk with a friend who was just leaviing, only to find myself shivering under clouds.  By the time I got to the top of the mountain it was snowing and in the clouds (fog) so you could not even see.  All the way down I got sprayed by snowmaking machines.  The visibility was so bad you could not see to ski.  There were sheets of ice that you could not see but that my brand new downhill racing skis could not get an edge into.  They did have some nice jumps built, and I caught some air, but the (lack of) visibility and ice made catching big air seem unwise.   I only stayed a little over an hour making like 10 runs.  wa wa wa.  Tomorrow will be crowded, but with only a fraction of the mountain open =
Group: AirborneWindEnergy Message: 10711 From: dougselsam Date: 12/6/2013
Subject: Re: Re, Reynolds number
Oh yeah I forgot to mention about Reynolds number:
While Re is a useful concept, one could have a fantastic wind energy career without ever having heard of it. I mean, it's not really something anyone HAS to know.  But as applied to wind turbines and propeller blades, chord is the relevant measurement D.  The thing is though, all one really has to know is that large utility-scale turbines are in a more efficient Reynolds regime, and the smaller you go from that utility scale, the closer you approach the "insect wing" regime, where viscous forces predominate over dynamic forces and airfoils for "lift" become irrelevant.  I've used a lot of Air-X and Air-403 blades with as little as 5/8 inch chord and found decent performance.  They used to use thinner and faster Selig airfoils at that low Re, but the more recent ones from the Air-X used a fatter airfoil with more camber. But experience says only large blades are likely to approach the Betz coefficient.  Smaller machines seem to be doing well if they can achieve 1/2 the Betz coefficient and are doing really well if they can get 2/3 of the Betz limit.  Part of that is probably smaller generators also being less efficient.  Still, fixating on definition after definition of modified versions of reynolds numbers really gets us nowhere.  Seems like you could create a fantastic airborne wind energy machine without ever having heard of a Reynold's number, and on the other hand, all the wind energy experts in the world, with all their combined formulas, coefficients, and know-it-all buzzwords, can barely grasp the fact that their dear turbines are really gyrocopters, mistakenly oriented sideways, just begging to be allowed to take to the air!
I'd rather build something that works than sit around all day seeing who can look up the most alternate definitions of various parameters formulae, coefficients, and buzzwords thatthey don;t even understand the significance of.  What good is a buzzword without having any idea how to apply it?
:)