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Flexor Energy Company

David Labrecque,                     David R. LaBrecque,  DavidLaB    http://physicsguy.org/about.html

Joe Paer
Ron Oliver
Chris Miller

This file started on Dec. 4, 2010.

  • Comment text by JoeF on Dec. 5, 2010:  Single Darrieus flexible wing. Wing rotates; pulses of force that bring end-points of wing together and then releases are convertible via linear generator to useful energy. Focus by David LaBrecque  is on the closing and opening of the distance between the two end points of the Aeroflexor; such oscillation of displacement is mined by linear generator or pump. 
    Tip speed ratios?  Power curves? 
  • Rotating sail fluid current motor Ralph Dorr
    Patent number
    : 4388041 Filed: Sep 8, 1980  Issued: Jun 14, 1983
    Discussion note by JoeF: Framed sail, single or multiple captive sails.  Agreeing with David Labrecque that Dorr focused on sails rotating central shaft for driving generator; and thus the Dorr direction is distinct from the Aeroflexor.
  • http://tinyurl.com/FrancePatentAppDarrieusLIFT
  • http://eolienneentremonts.monsite-orange.fr/
  • Wind turbine of type Darrieus on two buildings or two mounts
  • David Labrecque on Dec. 5, 2010
    The key feature of the AeroFlexor is that it extracts energy from the longitudinal motion of the endpoints
    rather than the lateral or rotational motion of the wing. Longitudinal motion is defined here to mean the motion
    of the wing endpoints toward or away from each other. My preliminary read of the Dorr patent indicates it extracts rotational energy from the lateral and rotational motion of the framed sail. There is no mechanism that converts the lateral motion to a longitudinal motion.

    I've been interested in the kite approach for many years now. Since the AeroFlexor extracts longitudinal motion, I can't think of a way to use it effectively as a kite. If one adds a fixed frame, weight becomes a problem. If one adds a second kite or balloon, horizontal lift and drag forces, may require the top kite to be significantly larger than the energy gathering middle kite. My experience and calculations indicate an AeroFlexor that leans backwards does not self start and the area that is exposed to the wind is reduced. It seems as though the Aeroflexor design is better suited to land-based rather than kite-based applications. This may be why I can't find a specific kite design that utilizes an AeroFlexor longitudinal energy extraction approach, but please keep me informed if you or your members find one.
  • JoeF on Dec. 5, 2010:
    Great. Welcome.
    I have included your team members in the AWEIA Founder's Circle.

    The cycling of longitudinal tether displacement on AWECS tethers occurs under several systems. The low cycling rate of reel-in-reel-out Yo-Yo methods aplenty are the slow cycling methods with power phase/cost phase timing ratio varying depending on system. The power phase may be very long and the cost phase very short; or the two phases may occur quickly. The Aeroflexor seems like a twitching contracting muscle to me, but the apparent cycle rate for contraction and elongation is not the shortest; hard lines twitching and pulsating with longitudinal hits from vibratory actions at a kite or lofted turbine can transmit longitudinal energy for driving pumps and generators at ground station. Damping events of tethers have discouraged many long-tether translation methods from getting much attention following recognition; the short end-point hold of Aeroflexor for the longitudinal actions does not have the long-line damping challenge and succeeds under the short-holdings that you have illustrated.

    Agreed on the Dorr item; he had high framed constraint and focused on rotation for the power driving of generator, not pulsing longitudinal mining.

    More challenging will be careful distinctions among the several findings of Dave Santos that have been published and are the foundation of significant investment. The total package of Aeroflexor and the various Membrane Wing-Mill stands to be in a high-following circle. Flutter has been in close focus also. Contracting-releasing tethers via several methods remains of interest. Lateral oscillations of tethers for mining energy also occupies many investigators. I draw your attention to three files; your team members are invited to help sharpen these files and any term's expansion or new inclusion in the Glossary (where Aeroflexor has status now)

    We have in community already in use membrane wing-mills (MWM) set integrated in tether that drive cranks and booms that in turn drive pumps and generators; Dave Santos is leading proponent of MWM that are scalable from tiny to truly huge installments. I must step aside and let Dave Santos' texts and discussions firm these matters.

    This is copied to Dave Santos of KiteLab and Pierre Benha´em, both who have interest in these matters. And to John Oyebanji, especially for your acceptance in AWEIA International, to which he may reply.

    Best to the Flexor Energy Company team,
    Joe Faust
  • Dec. 5, 2010 by JoeF:     The two-point rotating ribbon kite arch uses direct rotation via Magnus-effect to drive generators aloft or at the mooring station: http://www.energykitesystems.net/Kites/RibbonBowArchRotators/index.html These are distinct from working WMMs and from working AeroFlexors.
  • Dec. 5, 2010 by JoeF:  Playsails played with two human players have occupied people; they have enjoyed the closure of the end points as the playsail pulls and then dumps and pulls and dumps. Such oscillation and generation of energy conversion of the wind is fun.   The NKG Playsail.     I use my two-point holds of my paraglider for such playsailing; such really pumps my arm and shoulder and leg fluids...a real kiting workout.  These two-point wings have minimal rotation, but close their two end-points to drive movement of mass and liquids at the mooring points.  The infinity looping action in acrobatic sport paragliding has the wing rotate; the pilot operates the two end-points of the wing to control motions; the action has been achieved by two pilots in one wing: First Tandem Paragliding Infinite Tumble
  • Dec. 5, 2010 by JoeF:  Some spiders begin an oscillation of their web in response to a attack; the oscillation moves their body rapidly; the action is an energy input that send energy to other parts of the web.  Pholcidae Vibrating  and Vibrating Spider in India.  The spider's silk stretch and rebound during the process; some points of the web draw closer together and then rebound; the spider's input causes some longitudinal closure of some points.
  • Dec. 5, 2010 by JoeF: Rotors   These bols are mainly for display. 
  • Dec. 5, 2010 by JoeF:  Single-blade Darrieus has appeared in research.    Art1     Main focus: rotation for generation. Click their image for source.
  • Dec. 5, 2010 by JoeF: Musgrove VAWT ?  Self-furling?  Reefable?
  • Dec. 5, 2010 by JoeF: The jiggling of tethers on some Magnus-effect two-line rotary kites have been recognized as tether longitudinal or tether-translation pumpers that can drive pumps and generators ...linear and rotary.  Such rotation at the kite is via the Magnus-effect. This differs from the Darrieus wing flight.

  • Miles Loyd's tri-tether
    longitudinal oscillation of tether has kept interest among current investigators; he had the tethers oscillate from kite-lofted turbines; the mechanical energy was distributed via three tethers in one shroud in a preferred instruction. The Santos Tri-Tether differs considerably from the Loyd tri-tether; see message discussion within the above text link.       Miles Loyd's  US Patent 4251040 : click image for full instruction by Miles Loyd:

  • Dec. 5, 2010 by JoeF:   DARRIEUS WATER WHEEL TURBINE Peter Andrew Stabins, patent application, filed Application number: 12/296,580  Publication number: US 2009/0194997 A1 Filed: Apr 10, 2007. This focuses on the rotation of wings; hence this is distinct from the "end-point" displacement that David LaBrecque has in focus for generating useful energy.
  • An essay toward classification of wind systems.
  • Classification challenge for AWECS.  Comments are invited to advance the project.
  • Dec. 6, 2010 by JoeF:  Using the compression (or tension) of Darrieus wings at the axis? As the lift of the wing occurs, the end-points are drawn together; this is seemingly the Aeroflexor opportunity.  I have not seen if Dave Labrecque has or has not considered mining energy during both the closure and the opening phases via use of spring in combination with generator or not.   [ ]?    We have used two-way clutches and pumping for both directions in some AWECS; the zero-points at alternation are sometimes smoothed with flywheel energy or crank-move-through mechanics.      
    • http://www.windturbine-analysis.netfirms.com/index.htm
    • The variable-geometry Musgrove Darrieus tactics might be explored for string-drawing to drive linear generator; as the speed increases of the wing, then the pull-out of string or cable might be mined to drive a linear generator; saying this does not suppose that such mining would be better than mining the axial rotation of the Musgrove arrangement for generating electricity. Such oscillation of the radial string seems to parallel the Aeroflexor end-point displacement oscillation.
  • Dec. 6, 2010 by JoeF:    Autorotation (Darrieus radial-constrained wing, gyroglider, Savonius wings, Magnus-effect rotary wings, ..).    The Darrieus single wing AeroFlexor involves autorotation.

  • http://www.main.org/polycosmos/biosquat/kitemoto.htm
      On the page reached by clicking the photo will be a link that has a new address:    Now::

  • http://www.boatdesign.net/forums/attachments/sailboats/24122d1218338796-soft-wing-sail-wingsail4.jpg
  • http://www.main.org/polycosmos/biosquat/Sputnik3.jpg  Dave Santos   

  • Dec. 5, 2010, Dave Santos:  "-The Flexor Turbine is a Darrieus; and the "FlipWing" is a Wing Mill [Ed: also wingmill, wing-mill]. In video and diagrams it is easy to confuse them. Despite a key difference, they share most qualities."  See:  M2370,  M2689,  SomeMsgsInAWE SomeMsgsInEnergyKiteSystemsNet, The2006-9Drawings700pages Note25Feb2009,   [Ed: "Flexor Turbine" :: Flexor Energy Company's AeroFlexor.]    Wing-milling.  
    • Disambiguation: Strong leadership for "WingMill" is established by Trein, et al; such will relegate minor trade use of the term to a secondary status technically.   See Trein    and     M44   
  •  FlutterMill  Peter Allan Sharp and Jonathan Hare, CSC, March 2007        
    Dr Jonathan Hare, The University of Sussex
     Brighton, East Sussex. BN1 9QJ
    • Dec. 6, 2010: "I have made another breeze generator" ~~ Jonathan Hare

  • An Intermittent Wind Powered Generator        Look Mom, no reel, but a bit of Wright Brothers gravity game!
  • Controlled aerodynamic instability phenomena.
  • Dec. 6, 2010 by JoeF:   Three branches: 1. flutterers,  2. Darrieus wings,  3. sweeping flying oscillating membrane spanwise-tensionally-held wings (not Darrieus, not Savonius).  The three branches are investigated for airborne wind energy (AWE) installations that scale variously well from tiny to truly huge. Power curves are invited for each of the three branches.  Specialized applications of the three branches are invited to be described.
  • Buffeting
  • Dec. 6, 2010 by JoeF:    http://en.wikipedia.org/wiki/Aeroelasticity    "Flutter as a controlled aerodynamic instability phenomena is used welcomely and positively in wind mills for pumping or generating electricity or other works like making musical tones on ground-mounted devices as well as on musical kites. Flutter is not always a destructive force; recent progress has been made in small scale (table top) wind generators for underserved communities in developing countries, designed specifically to take advantage of this effect.[2][3] FlutterMill by Peter Allan Sharp (of Oakland, California) and Jonathan Hare (of University of Sussex), March 2007, demonstrated a linear generator run by two flutter wings. Distinctions are made in the wind-energy industry between flutter wings, flip wings, and oscillating tensionally-held sweeping membrane wings for wing milling.[4]"
  • Dec. 6, 2010 by JoeF:    The Darrieus rotor of the AeroFlexor removes the conventional central rigid axial shaft and allows the wing end points to approach one another and also return to extended positions; such displacement of the end points conventionally is constrained and stabilized by the axial shaft of Darrieus wind mills; differently, the Darrieus-dynamically-acting AeroFlexor  without the constraining conventional axial position stabilizers is set to drive strings or cables by the displacement of the end points which in turn may drive pumps, do works such as sawing, or run generators of various sorts including linear generators.  The Aeroflexor is not a flutter device and is not a sweeping wing, but a rotating Darrieus wing that exchanges absolute-constraining-of-wing end points with a constraining method that allows the end-points' oscillating displacement to do useful works.   [ ] Investigation of the full Darrieus wind mill history would be needed to see if any investigators or users mined the contraction-tendency of the distance between rotor end points; experts on Darrieus wings are invited to discuss these matters.
  • Dec. 6, 2010 by JoeF:    WindBelt or  windbelt  is a fluttering device. This is distinct from Darrieus wings,  flip-wings, tensionally-held-spanwise oscillating-sweeping cross-winding membrane wing mills, fluttering strings, or rotating spider silks.
  • Power Generation from Aeroelastic Flutter at Low Reynolds Number
  • Tech Brief: Efficient small wind power, without turbines
  • Humdinger's Wind Power Alternative
  • http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge
  • Dec. 6, 2010 by JoeF:      Stall, re-staring, and self-starting issues concern developers and users of flutters, rotors, and flip-wings.      The kite- or kytoon-lifted flip-wings receive ambient gusts that play well to maintain working status of the in-tether device.  Demonstrations and reports regarding stall, re-start, and self-staring are invited in all three branches: flutter, rotor, and sweeping flipping.
  • Trein  (his scientific works)
  • Dec. 6, 2010 by JoeF:  Lift stresses are employed by the Aeroflexor to vary the end-point positions.  During cycles of the Darrieus rotation, the lift is with maximums and minimums; the change is opportunity for pulsation of the distance between end points of the wing.
  • Dec. 6, 2010 by JoeF:    The SkyBow or rotating ribbon is a Savonius device that obtains lift for the bow via the Magnus-effect; the SkyBow rotating ribbon (either as kite or breezeway decoration traverse to breeze set at any angle in the traverse plane)  is not a Darrieus device. The AeroFlexor is autorotating via the Darrieus dynamics with constrained axis with wing fully positively set away from the axis so an air gap obtains.
  • Dec. 6, 2010 by David LaBrecque:                       [Hyperlinks added by Ed]
    Morning DaveS,

    Thanks for your feedback on this and your contributions to this productive forum.

    You're quite right that the non-rotating fishtailing AeroFlexor is identical to the wingmill. I had included "other patents apply" in my technology overview regarding fishtailing, but I dropped it in the latest version.  I'll be sure to include it in the next version in January.

    I've also been intrigued by the sky bow approach, but I could never figure out how to get it to sweep up and down so that it could extract energy from a larger area of wind.

    Gravity presents complications with the weighted (ballasted) horizontal AeroFlexor. Our preliminary experiments, unfortunately, indicate rotation starts and works better with the wing rotating such that it flies down rather than up.

    At this point we have put off directly generating electricity and are focusing on pumping applications (i.e., irrigation, aquaculture, drinking water, energy storage). Electricity could be generated from the energy stored as compressed air, or elevated water. We lose some efficiency, but the overall system is so low cost, we are ok with that.

    I'm not sure I can add anything new to the generator issue that you are not already aware of. My first thought is a lightweight ultra high voltage Van de Graaff type generator. Weighting on the AeroFlexor is critical to its operation, but so far we use just dead weight. Perhaps that weight could incorporate a generator? Or the generator could be incorporated into the tether. I'll pose some of these questions to faculty and staff in chemistry and physics here at the University of Maine and to the students in our Flexor Energy student club.

    Thanks again for all of the information and I'll keep you informed on our progress.

    Dave Labrecque
  • Dec. 6, 2010 by DaveS:  Regarding your notes-

    The AeroFlexor in "fishtailing" mode is identical with our wingmill's sole power mode. We do not need ballast (but have experimented with it). Its true that a lifter kite needs to be considerably bigger than the sweeping wing's area, but swept area is greater overall. Angling our flapping wings to windward adds lift. A short sharp pulse by the wing is well resisted by the lifter kite's area, although some loss occurs. A pulley/drogue is sometimes used as a bottom corner-block to redirect more power back to a single anchor point. Another powerful configuration of interest is to set the wing horizontally crosswind. Your wing flown like this is a sort of enhanced "sky bow", a spinning ribbon acting more as a Savonius turbine than your Darrieus device. Both concepts generate useful Magnus-Effect lift.

    The sort of pulses we both get can be converted to nice rotary motion by many mechanisms, but tuning is critical. It took a couple of years working with "FlipWings" to "find" all the missing "kite grunt" power. The basic requirement is to extract power without giving much distance downwind, or the wing is sapped. Let's share work on the generator interface and propose side-by-side testing (by NASA even, see previous post) of the two kinds of flexible wing to see which is better at what. My guess is the lighter wing is favored for kites and the ballasted Flexor is slightly more powerful otherwise.

    These ideas will scale-up incredibly and can even be aggregated in dense synchronous arrays. It is time to get a sailmaker to sew us up some bigger wings to test.
    Best of luck,
  • Controlled Aerodynamic Instability Phenomena
    - An Alternative Approach for Wind Power Generation Systems

    In this study the concept of Controlled Aerodynamic Instability Phenomena is proposed, as an alternative approach for Wind Power Generation systems. The concept is based on the idea that aerodynamic instability phenomena, such as Karman Vortex Shedding, Flutter, Galloping and Buffeting, can be driven into a useful motion and be used to extract energy from the flow. A case study using the flutter instability is presented and the concept is proved feasible. By using a forced torsional oscillation, the heaving motion is induced in a bluff body, so the energy generated by the heaving motion is estimated by both analytical and experimental processes, converging to the same conclusion. Finally, the results are discussed and alternatives for future developments are introduced.

    MATSUMOTO, M.; TREIN, C*.; ITO, Y.; OKUBO, K.; MATSUMIYA, H.; KIM, G. - Controlled Aerodynamic Instability Phenomena - An Alternative Approach for Wind Power Generation Systems. The Nineteenth KKCNN Symposium on Civil Engineering, Japan, 2006.


  • Peter R. Payne  
    Patent number
    : 4024409
    : Jan 7, 1975
    : May 17, 1977.
    Aeolian windmill

    [Ed: This instruction will set the scene for some interesting discussions, I trust. ]
    • unisail reciprocating windmill
    • Strouhal number
  • single blade unisail
    Strouhal number
    oscillating cylinder windmill
    60-Hertz system
    aeolian A.C. generator
    oscillating conductor
    "two end points"
    utilization device
    magnets in an orientation parallel to the
    relative wind
    tensioning device
    jack screw
    wind sensors signal tensioning device
    cup anemometer
    hard wired or coupled by radio link
    amplitude h/2
    first mode of resonance
    pump stroke will be approximately 8/3 h^2/l
    pumping action : see conventional pumping
    Omni-directional system
    resonant system
    torque bar
    variable pitch
    blade pitch angle
    theory of binary flutter
    coupled torsion and flap
    automatic feathering techniques
    peak stresses
    power taken from the element
    The attainable efficiency values will depend
    on the level of sophistication built into the
    aerodynamic element and particularly the
    limits of oscillation efficiency.

    The element may receive the attention of those skilled in the art; thus airfoils ...
    The element's tensioner may be under guide of those skilled in the arts; so a lifter kite could be employed, I would say.
  • Payne patented further: US Pat 3987987 teaching and remind readers of many things.:

  • Windmill   Arlon J. Hunt [ ] US Pat. 4396852  He comments on Payne.
  • Compare and contrast WindBelt or Wind Belt with Flexor Energy Aeroflexor and the Aeolian wind mill instructions of Peter R. Payne.
  • For this topic, please send information, comments, and links to Editor@UpperWindPower.com
Dec. 15, 2010: Update from David Labrecque:

The Aeroflexor team now has a 2 meter AeroFlexor prototype pumping practical amounts of water. In the next month we'll use water pumping to produce power curves.

We're also excited about the latest HydroFlexor test. A very simple 0.5 meter wing made out of a thin steel strap was tested in a water current at 1.8 mph. We connected it to a water pump similar to the one in our AeroFlexor test. The HydroFlexor self-started like the AeroFlexor, rotated uniformly and had a good pumping action. A longer wing and/or a slightly faster current should be able to pump practical amounts of water. We'll be generating power curves for the HydroFlexor in the next two months. The HydroFlexor test also provides useful information on AeroFlexors since the hydro-version should be roughly similar to the aero-version scaled up by a factor of 13.

Its important to note again that the Aeroflexor works differently than the WingMill. As Dave Santos wrote:

"Your device is not on the same principle as KiteLab's WingMills, they just look alike in video. KiteLab's device is not a Darrieus, but "flaps" crosswind, rather than rotating."

This confirms that our team is really pioneering new territory, which is a big motivator for us.

Thanks again,
David Labrecque

Dec. 15, 2010        Dear David LaBrecque and AeroFlexor team.,

Congratulations on your rapid progress. We are independently validating the potential for large membrane wings to be a super cheap and highly scalable method of tapping geoflow energy.

KiteLab's wingmills share a basic constraint with the Aeroflexor, that they do not "fire" at the angle of a single kiteline, but many practical workarounds exist. Its not hard to hang these wings off the kiteline on a separate line so they set vertically. The pulses can be redirected to the anchor by a corner-block  tensioned by a small drogue, or they can just be directed to a dedicated ground workcell underneath. Setting the kiteline up as an A-frame or tripod, or creating vehicle-anchors allows the wind to veer. The ultimate solution is to fly a mesh of kites (or balloons, or cables hung from terrain) with nodes for hanging wings vertically in a fixed pattern. Such meshes can be rigged to accept wind from any direction. Tilting the wings a bit to windward develops some useful lift & should allow reduction of ballast mass further.

You may find inspiration in the recent work of Prof. Dabiri in clustered pairs of Darrieus rotors and how Darrieus even beat HAWTs by "super-density" operation.
Biological Propulsion Laboratory at CALTECH [Wind Energy Research]

Thanks for keeping the Airborne Wind Energy Forum informed,

dave santos
KiteLab Group
Dec. 15, 2010           The full play of Payne, Frayne, Santos, Benha´em, Faust, Sharp and Hare, and Labrecque will become one of the large stories in the advance of wind energy.   Oscillators rule a sector in AWECS a-coming!  Looking at the Wright-Brothers-and-Curtiss discussions under action in 1913 urges me to avoid similar dance in the AWE world. May each emphasis find effective blessings to those in most need!  Design, engineer, test, promote, serve ...there is a huge world market for oscillators driven by distributed wind and water flows!   JoeF
Dec. 15, 2010 
In response to some of the recent comments:

The weighted Aeroflexor patent does not cover oscillating wings like in the Payne patent or rotating single wings where energy is extracted from rotational motion. The patent only covers a rotating flexible wing secured at two ends where energy is extracted from the longitudinal motion at one or both endpoints.

It's fascinating that spiders use a rotating leaf on a long web strand to fly and travel, but they don't use these forces to pump fluids or generate electricity. Someone has to invent a way of doing that with AWECS. Having said that, Aeroflexor experiments have shown that lateral movement significantly reduces the efficiency of the longitudinal energy extraction method. Basically the wing moves with the wind as it rotates which significantly reduces the lift forces that cause the wing to rotate and pump longitudinally. My best guess is a rotating wing is not a practical approach and an oscillating wing which spends more time facing more into the wind will work better.

Here is something I'd like for Christmas: A super-charged airfoil kite where the wind causes the charges on the airfoil to move and create a varying charge difference across the kite (an airborne Van-de-Graaff generator). The tethers transfer this energy to the ground forming a high voltage current loop. Seems like a good idea, at least until I start crunching the numbers.

In any case, Merry Christmas/Happy Holidays and thanks for the valuable input on Aeroflexors.

Dave LaBrecque

Click through for instruction.
Maybe have the belt be rotated by a kited turbine with wipers at the ground stations.     FanBelt method with the added features described by Isoya and Yosinaga might be one expression toward your Christmas gift. There are others to be put on the table.
JoeF                               15Dec2010
Darrieus matters

  • Single-vane turbine of the Darrieus type


  • Single-blade Darrieus has occurred in the literature; though Ken Brown illustrated such in his patent, he was not of those that saw benefit in the single-blade Darrieus.    Also, single-blade propellers for powered aircraft and for powered helicopters are exposed in the literature. The autorotating seed has inspired single-bladed explorations; maple seed flight. Many of these are counter-weighted when the off-balance is not wanted.   USPat. 4561826    1786057    1802094    2605093

  • As Faust (writer present) noted in Kite types wiki, nature has daily provided us with flexible wings in leaves that get caught in spider webs in very many conformations ending up in leaves being spider silk tether kites wafting in the wind to stretch the spider silk line; sometimes these are single-lined kites; sometimes the leaves end up as double-line kites; sometimes a multiple web holds the leaves while the leaf gets wafted by wind with lift and drag reactions occurring; a walk in the woods will let one view these natural exhibits; some will be rotating Darrieus-wise as the Aeroflexor does; some will sweep and lift and fall as a single-line kite; others will stall and then restart oscillations as gusts occur; some will make large sweeps instead of circularly rotating; those skilled in the arts of kites have recognized these natural arts. When the leaf is long and is caught just right in short hold to branches, a natural AeroFlexor occurs with longitudinal tugs on the end silks that in turn slightly tug branches ....conversion of wind energy to mechanical energy: AWECS from the works of spiders and trees working together with the wind.
  •   [ ] Look to advertising attention-getting line spinners, fish lures, noise makers, garden decorators, and kite laundry. Single-blade whirligig parts used by sculptures ...
Just aside of page topic

Consider also flying a kite left and right to drive that boom!  New sky-oil drilling!

  • [ Ed: Up and down and up and down ... Move over oil derricks ...the wind is coming.]
Savonius matters (distinguish from Darrieus via TSR, air gap, airfoil lift emphasis,  ... )
Oct. 3, 2011  
Hi Dave,
I have found a cool horizontal mode for wings like yours.

When looping backwards like a jump rope stretched crosswind such wings can actually self-sustain flight by generating net lift. The wing can be launched and probably better sustained by kites on pullies at each side. Power can be extracted from the ends. It should even be possible to reverse-pump this rig to sustain flight in calm, with even the side kites towing in small circles. Yes, its a weird set-up, but pretty cool...

Also, as you scale up, ballast mass is unneeded, as wing mass grows at the cube of size,

dave santos
KiteLab Austin