- 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.
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:
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
Agreed on the Dorr item; he had high framed constraint and focused on
rotation for the power driving of generator, not pulsing longitudinal
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
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,
- 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:
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:
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.
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:
These bols are mainly for display.
- Dec. 5, 2010 by JoeF: Single-blade Darrieus has
appeared in research.
Art1 Main focus: rotation
Click their image for
- Dec. 5, 2010 by JoeF: Musgrove VAWT ? Self-furling?
- 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.
- 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:
(Darrieus radial-constrained wing, gyroglider, Savonius wings,
Magnus-effect rotary wings, ..). The Darrieus single
wing AeroFlexor involves autorotation.
On the page reached by clicking the photo will be a link that has a new
- 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:
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
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.
- Dec. 6, 2010 by JoeF:
"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. 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."
- Dec. 6, 2010 by JoeF: The
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 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
Power Generation from Aeroelastic Flutter at Low Reynolds Number
Tech Brief: Efficient small wind power, without turbines
Humdinger's Wind Power Alternative
- 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.
(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
- 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.
6, 2010 by David
[Hyperlinks added by Ed]
Thanks for your feedback on this and your contributions to this
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
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
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
- 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
Filed: Jan 7, 1975
Issued: May 17, 1977.
[Ed: This instruction will set the scene for some interesting
discussions, I trust. ]
- unisail reciprocating windmill
- Strouhal number
- single blade unisail
oscillating cylinder windmill
aeolian A.C. generator
"two end points"
magnets in an orientation parallel to the
wind sensors signal tensioning device
hard wired or coupled by radio link
first mode of resonance
pump stroke will be approximately 8/3 h^2/l
pumping action : see conventional pumping
blade pitch angle
theory of binary flutter
coupled torsion and flap
automatic feathering techniques
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
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