CoolIP index                                                          Most recent edit: Wednesday October 24, 2012

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Vertical Shunting Arches- A New AWES Architecture

Kite shunting is a cyclic reversal of flight direction, with leading-edge and trailing-edge alternating. Four-line kites shunt, but most do it poorly. JoeH's Rev kites are good shunters. AWE shunters are a general category of wingmill. KiteLab Ilwaco has shown by small experiments that horizontal shunting by a suspended wing is a workable mode.

Vertical shunting, with a One Stick Diamond Kite set as a Kite Arch, is now also shown to be an effective AWES mode, with advantages in stability and control. Besides potentially driving ground-based electrical generators, this general method has high promise for high-speed, precision, and heavy-lifting applications.

This particular discovery came about by accident; i accidentally flipped an arch-rigged "billowing set" one stick diamond kite, and it took on a reflex shape and parked totally stable at its zenith without a tail. I then put a sheet line on it and was able to whiz up and down powerfully. It seems more than ever that staking kites out crosswind is a key to large scale power.
JoeF will link us the videos and collect the new kite arch variations on one link page. They are closely related even, if they look different. One image shows a recycled arch made from seven random diamond kites, but with seven sticks eliminated. 2KiteSam fitted grommets to the empty corners to rig a drawline furling arch. The furling worked, but excess friction was evident and a new frictionless furling rig is pending. Other upcoming demos will integrate multiple shunting kites and arches in variations, with large tarp arches making a special debut.

CoolIP*                      ~Dave Santos                 22Feb2012                    AWES5898

Comment and development of this topic will be occurring here.       
All, send notes, drawings, and photographs!

  • Video Vshunt_demo.avi
  • Landing video of Vertical shunting kite arch   Vertical shunting with a One Stick Diamond Kite is hereby shown to be an effective AWES mode, with advantages in stability and control. Besides potentially driving ground-based electrical generators, it has high promise for high speed and heavy lifting applications.
  • ShuntingKiteArches/RecycledKiteArch.jpg       Recycled Kite Arch with Furling
    • Note of March 24, 2012: "One more small test toward filling the sky with kite lift someday; the attached JPEG shows an arch of misc. kites simply rigged, showing once again how kites can be aggregated to scale up as a "metakite". Next studies are with multi tarps for megapower, but diamond kites thirty feet tall would be pretty powerful.

      Flies real nice, at about 60 degrees; had to wait for a lull to photograph it low enough to catch the harbor landscape, it actually self landed and relaunched several times during a couple hour session, very tamely. This is a good kite arch and the basic methods have great potential.

      Learned a lot about how to avoid making a mess stowing and setting up (by making a mess). Tested without tails, and then with tails, and they definitely helped greatly to make this very stable and tame with no loss in flying angle noticed.

      The Furling 1.0 barely worked, with too much friction in the drawline passing thru all the grommets, but I see a nice way to furl with no friction and balanced forces, so will re-rig for that and do video.

      Sam and I flew this arch in a near gale, and it flew, but with very distorted sails and spars."  Dave Santos


Pending shows:

  • [ ] Other experiments are on the way ...

Terms and aspects:   

  • Distinguish between a kite arch that is not shunting and those that are vertically shunting.
  • shunting kites, kite shunting   See related matter:  Shunting
    • Vertical Shunting Arches- A New AWES Architecture   
    • shunting kite arches  (long and short stroke).   
    • Two sorts: rotating always in one rotational direction for edge exchange is one type; other type is AoA change just enough to cause role exchange of leading edge for trailing edge in alternation.   Variation occurs win long strong where exchange of roles is by either method of same direction rotating or reverse AoA just enough to achieve role changes for the edges.   JpF
    • flip-wing kite arches and flip-wings also alternate leading edge to trailing edge to leading edge, etc.  The rotating ribbon SkyBow is a flip-wing kite arch with short stroke.
    • _______________
    • shunters
    • kite shunting
    • AWE shunters are a general category of wingmill.

Related links and concepts:

Commentary is welcome:

  • Review note: 
    • A kite arch may have continuous wing material or wing elements with raw-tether segments between the units.
    • A kite arch may be a flip-wing sort or not. 
    • Non-flip-wing kite arches may be of two sorts: 
      1. Shunters (being explored by KiteLab, Ilwaco, Washington, USA, and topic of this file.)    
      2. Non-shunters.  Notice that the old art of AoA changes to guide non-flip-wing kite arches up or down vertically  has the extreme of full shunting where driving leading edge is role exchanged by leading edge-trailing edge without continuous same-direction rotating, but of long stroke AoA alternations.
    • Notice that, especially on long-stroke AoA changing, there is cross-winding occurring (but vertically); the extreme advantage occurs when full flip of role changes in long vertical stroke with high time in cross-winding, i.e., occurring in the climb up and in drive down.
    • We  do not forget the whale tail items in windpower where drive exchange occurs in a wing that drives up and then later drive down by AoA severe changes at turn points.
            JoeF       27Mar2012
  • Consider:  arch of trains ::  Consider a system that has two anchors spread far left and right of the power window; the arch is maintained by a series of elements where each element is not just one wing, but a train of kite wings; the whole is a series of trains that lift an arch.  Those trains might be stable lifters for some niche uses.   Also, those train elements that form an arch might be vertically-shunting trains for some niche uses.     JoeF    28Mar2012
  • April 2, 2012   by Dave Santos of KiteLab, Ilwaco and Austin:   
    Kite Arches for Crosswind Power                
    Here are some notes toward a formal theory of operation for Kite Arches, extending Loyd's crosswind power concept to crosswind arches, and equating the flight characteristics with Culp's "staked-out" stability principle. Basic geometric proof, covered elsewhere, applies in showing that arched structures far outperform single tether AWECS by airspace/land-footprint scope to power ratio.

    Miles Loyd famously coined the term "Crosswind Power" to describe crosswind sweeping wings like a HAWT blade or looping kiteplane, but the essence of Crosswind Power is broader than that, as every WECS requires a crosswind extent to operate. Crosswind Power is really a continuum, from high-speed sweep to static lift. A parachute decelerator works by spreading area across its apparent wind, and so is seen as the lower tech boundary of Crosswind Power. Decelerator-based AWESs exist, from spin-canopies to pulsing varidrogues. The lowly varidrogue is wrongfully objected to as more downwind than crosswind in operation, but a close look at virtually all AWES concepts reveals considerable depth-of-section downwind. There is seemingly no purely crosswind WECS.

    The unique virtue of Kite Arch engineering physics is to resist cross-field forces by a balanced minimal geometry of catenoids, a set of curves. To compute an ideal compressive arch, merely hang a chain and use that catenary curve upside-down.

    A Kite Arch essentially eliminates common tether drag, by being quasi all-wing. By contrast, a static single-line kite tether is fairly high drag, with some down force (negative lift). Worse, a looping single-tether kite inscribes a troposkein, the form encompassed by a jump-rope, "harvesting" high drag.
    Vertical Shunting Arches is the latest Kite Arch method. A VSA inscribes a catenoid minimal-surface in the sky. Special magic emerges when mathematical perfection is approximated in the real world. Catenoids may prove to be the optimal wind harvesting geometry, using the least material for maximal output. KiteLab had been for years hanging WingMill arches from lifter kites and shunting or tacking them crosswind horizontally, also inscribing a catenoid.

    Suddenly the Kite Arch emerges as a competitive AWES architecture, but there are key antecedents. We first note primitive arches from multi-line kites from traditional Polynesia, then into the 19th Century Kite Golden Age, with even manlifting accomplished (Baden-Powell), but it seems only in recent decades did the Kite Arch emerge as a well defined category. The first Kite Arch that I learned about was my net friend Anders Ansar's Ribbon Arch, followed by Peter Lynn and Dave Gomberg's kite show arches flying multiple theme soft-kites closely together off a common gangline set crosswind. George Peters also did great work on Ribbon Arches, before Anders.

    The World Kite Museum then opened up to me a whole world of special Kite Arches, seemingly tracing from Ohashi's 1980s discovery that he could bend a certain kind of Kite Train (diamond kites) almost 180 degrees into an arch set crosswind, and it would continue to fly. Some unknown person at about that time seems to have figured out how the diamond kites could be fully integrated into the arch line, eliminating all the cross-sticks. Since then hundreds of kitemakers have made such arches, generally without tinkering with the design. Other arch variants emerged, from rotating SkyBows. In all cases Kite Arches set crosswind.

    When Dave Culp at KiteShip first informed me in 2007 that "staking out" a large kite tames it, i did not make the connection to Kite Arches. It was only last week that this mentally clicked into place. Not only is the Kite Arch a Crosswind Power device, but it incorporates a powerful kite stabilizing principle, that the ground surface itself is the most robust and stable kite structure possible. One even sees this principle in the common arched traction kite parked at zenith off its control bar. A fantastic advantage to Kite Arches is the ability to kill them in a controlled progressive linear fashion by slacking on side. The arch lays down from its windward point. By contrast, "kite killing" single tether AWES is always more complex or risks retract winch saturation.

    Kite arches and trains naturally combine by setting the trains across the arches, from lower to upper. Multiple arches sum tremendous lift, while also stabilizing close-set trains from interfering. Fry and Hines naturally envisioned trains of WECS in their rigid wind power arch structure, set crosswind. We now see how a Kite Arch can do the job cheaper and better by going higher. A growing list of methods exists to rotate a Kite Arch to match wind direction-- Hauling and Belaying around an Anchor Circle, Anchor (ground) Vehicles, Giant Carousel, Giant Control Bar, Circular Track, Circular Cableway, Buddy Boats, etc.

    In summary, there are many bulk advantages to Kite Arches. The challenges with arches are mostly in the details. An "anchor field" is a key arch requirement. Kites in a network can tangle badly if poorly designed and carelessly operated. The Bow-Tie failure mode is most characteristic of a high AR arch wing; deep-section bridling, foil section reflex, and/or tails constrain a wing arch from flipping; local swivel sections can recover a BowTie flip. 
    April 2, 2012   by Dave Santos of KiteLab, Ilwaco and Austin

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