Half a croissant, on a plate, with a sign in front of it saying '50c'
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a wind turbine with blades that flap
  (+16, -3)(+16, -3)
(+16, -3)
  [vote for,

This wind turbine would not generate power from a rotor but from two blades that move smoothly up and down. Each blade is hinged at the base and balanced with counter weights. By changing pitch, the rigid, 20 meter blade captures the wind while traveling in either direction, with even transitions at the outermost points.

Though less efficient than a rotary wind turbine, the flapping wingmill would be more pleasing to the eye. A V-shaped wind farm would look like a flock of giant, white geese flying south.

FarmerJohn, Oct 21 2002

(?) Wind power info http://www.windpower.org/tour/index.htm
[FarmerJohn, Oct 21 2002, last modified Oct 21 2004]

(?) oscillating hydroplane http://www.engb.com/Pages/demo.htm
[FarmerJohn, Oct 04 2004, last modified Oct 21 2004]

Great Horned Owl, on a stick. http://www.safehome...ces.asp#Prowler_Owl
[Amos Kito, Oct 04 2004, last modified Oct 21 2004]

Fluttering Wind Energy - Windbelt http://www.popularm...dustry/4224763.html
Oscilating wind generator - alternative to wind turbine [pashute, Mar 12 2010]

Wheel-o http://www.physlink...ticGyroFlyWheel.cfm
[Klaatu, Mar 12 2010]

Scientific research on baking this idea http://www.springer...t/x2vm2m6964767568/
Oscilating wind powered electric generator [pashute, Mar 25 2010]

List of oscilating generator ideas http://www.vortexos...&pa=showpage&pid=87
Proving this is a great idea. [pashute, Mar 25 2010]


       What a stupid idea.
Gulherme, Oct 21 2002

       Why ? It's probably practical to build. And it could be built lower to the ground than conventional rotary windmills.
8th of 7, Oct 21 2002

       I know someone who has a phobia of flapping birds. This would give her the willies.
namaste, Oct 21 2002

       phobia of willies as well?
General Washington, Oct 21 2002

       [FarmerJohn] This is lovely! It sounds Utopian.   

       Your wingsmill's airfoils aren't constrained to a hub so you won't have the same drag force impeding rotation of the rotor. You get to take advantage of a higher "lift" ratio for starters and then perhaps a little gravity...   

       I think you might just give the old wind turbine a run for its money FarmerJohn!
hollajam, Oct 21 2002

       Is that that mind of yours sinking towards the gutter again General Washington?
namaste, Oct 21 2002

       This is roughly the format of wave-power generators, so the mechanical conversion is obviously possible.   

       One advantage that springs to mind is that the flapping blades will present a much smaller hazard to migrating birds than the whirring propellers of a regular modern windmill.
DrCurry, Oct 21 2002

       [namaste] "plop."
General Washington, Oct 21 2002

       I like the visual. +
blissmiss, Oct 21 2002

       [bliss] has her own geese?
Cedar Park, Aug 16 2003

       Didn't you know that about her? She's a long time goose disciple; an old geeser.
bristolz, Aug 16 2003

       Get the timing of the pitch changes wrong, and see the geese crashing into the ground.
Ling, Feb 24 2004

       I actually build some of these when I was in art school, more as a artwork than a powergenerator. They were beautiful.   

       The downside is that the wind is much less strong and steady as you get closer to the ground.
macrumpton, Jun 03 2004

       I was wandering the internet hoping no-one had invented the oscillating-wing windmill, and found this. It always surprises me when HB ideas come up in "serious" searches.   

       This would be beautiful. And useful for pumping water and compressing air. A somewhat stale, but well-deserved, croissant and an churn of the windmill to [FarmerJohn].
baconbrain, Aug 29 2008

       No-one could complain that a wind farm made of these was ugly.
wagster, Aug 29 2008

       Ban users who call ideas stupid, without giving any reason. (oops - meant this anno to be under HB Culture)
pashute, Mar 12 2010

       [Gulherme] could just have easily given this idea a [+] or a [-] after that comment. It's hard to tell.
wagster, Mar 12 2010

       I have always conceived of wind turbines capturing a "patch" of wind and their output being limited to the frontal surface area multiplied by their efficiency at the prevailing wind speed. I know that this idea is more attractive than a conventional turbine but I see no reason to believe it offers any benefit due to the fact that it can only present a very small frontal area and would have a very low efficiency at all wind speeds. Water and air are very different creatures and you must design differently for the two, it is "foolish" to thnk that a design that works in a liquid will work in a gas.
WcW, Mar 12 2010

       main issue is conservation of momentum, stopping the wing and switching direction takes energy, you're better off with a huge funnel that makes the wind go toward a single set of blades, or a rotary windmill for less flutter and more ascetics
Arcanus, Mar 12 2010

       I dunno, [Arc], about wasting energy. I think you could capture the energy required to stop and re-start the wing movement. Either bounce it off a spring, use the momentum to do the final bit of compression of a pump, or some such. Or link the whole thing to a big flywheel.   

       It would take some design work, but I really cannot see an oscillating wing being automatically less efficient. But I do think one would be more useful for things like pumping water than for generating electricity in a smooth output. Other advantages would have to be present, of course, but the posting lists one advantage.   

       And after all, birds seem to get along pretty well by using oscillating wings to put energy into the air. Us humans might be able to figure out how to do the reverse.
baconbrain, Mar 12 2010

       If the blades were "tracked" (a la the Wheel-o toy <link>) Could the angle of attack be changed more smoothly? I envisioned a sort of figure-8 track.
Klaatu, Mar 12 2010

       ok i can envision a way to do this where the wings pump a wheel and switch direction at each extreme. wish i could post a picture of what i envision, but i still think it wont be nearly as efficient as a propeller
Arcanus, Mar 12 2010

       This is a lovely idea!!! It should be built, big.
MaxwellBuchanan, Mar 12 2010

       Ideally, it should power something that needs a reciprocating, rather than a rotary motion. A piston pump, maybe. Or how about this: For hang-gliders, in flat-but- windy terrain: on the downstroke, it hauls (cable, hook) the hang-glider up to the top of a pylon. The glider then detaches, and glides away, hunting thermals like a vulture. On the upstroke, the hook descends for the next hang-glider.
mouseposture, Mar 12 2010

       If an anno on halfbakery is really bad, is it possible to delete it? I can't stop getting angry every time I enter this page and see Gulherme's remark on top.
pashute, Mar 25 2010

       [mouseposture] Each "bird" is a pair of counter-rotating partial arcs with each flap... but the "downflap" of one side is in the same direction as the "upflap" of the other, so apart from inertia when the wings are switching from up to down and vice versa, you could get reasonably steady counterrotating circular motions.
FlyingToaster, Mar 25 2010

       The originator of this idea is not currently posting on the 'bakery, and he's the only one that could delete the anno.   

       It does seem like the annotator was having a bad day - I'm not familiar with their work and attitude.
normzone, Mar 25 2010

       [FlyingToaster] Oh, I realize it's easy to convert reciprocating to circular motion -- that goes back to Watt & Chebyshev. I just thought it'd be more elegant to use reciprocating motion directly, without converting. Also, I liked the conceptual "rhyme" of giant flapping wings launching smaller flying things.
mouseposture, Mar 25 2010

       [mp] the motion is already circular(arc), though.... well, it is if each bird has two wings that pivot from the centre.... ... which I'm not sure from reading the post.   

       [pashute] it isn't a turbine and wings aren't designed to provide lift efficiently in both directions.
FlyingToaster, Mar 25 2010

       Further sources of inefficiency: A wing that pivots needs a twist to be efficient; which makes it even more difficult to get efficient lift in both directions. The blades will spend a disproportionate amount of time at the top and bottom - where the direction changes. The swept area looks like ><, rather than O, so far less wind will be harvested than in a rotary design for a given blade length.   

       So, yes, it's a stupid idea [+].
spidermother, Feb 10 2012

       Surprised a town hasn't made the "world's biggest seagull" as a tourist attraction that has utility too.
FlyingToaster, Feb 10 2012

       //What a stupid idea.//   

       I agree. [+]
Wrongfellow, Feb 10 2012


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