h a l f b a k e r yI never imagined it would be edible.
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Wingmill
a wind turbine with blades that flap | |
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.
(?) 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]
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Annotation:
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Why ? It's probably practical to build. And it could be built lower to the ground than conventional rotary windmills. |
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I know someone who has a phobia of flapping birds. This would give her the willies. |
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phobia of willies as well? |
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[FarmerJohn] This is lovely! It sounds Utopian. |
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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... |
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I think you might just give the old wind turbine a run for its money FarmerJohn! |
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Is that that mind of yours sinking towards the gutter again General Washington? |
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This is roughly the format of wave-power generators, so the mechanical conversion is obviously possible. |
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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. |
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[bliss] has her own geese? |
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Didn't you know that about her? She's a long time goose disciple; an old geeser. |
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Get the timing of the pitch changes wrong, and see the geese crashing into the ground. |
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I actually build some of these when I
was in art school, more as a artwork
than a powergenerator. They were
beautiful. |
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The downside is that the wind is much
less strong and steady as you get closer
to the ground. |
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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. |
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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]. |
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No-one could complain that a wind farm made of these was ugly. |
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Ban users who call ideas stupid, without giving any reason. (oops - meant this anno to be under HB Culture) |
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[Gulherme] could just have easily given this idea a [+] or a [-] after that comment. It's hard to tell. |
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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. |
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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 |
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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. |
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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. |
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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. |
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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. |
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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 |
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This is a lovely idea!!! It should be built, big. |
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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. |
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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. |
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[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. |
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The originator of this idea is not currently posting on the 'bakery, and he's the only one that could delete the anno. |
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It does seem like the annotator was having a bad day - I'm not familiar with their work and attitude. |
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[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. |
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[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. |
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[pashute] it isn't a turbine and wings aren't designed to provide lift efficiently in both directions. |
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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. |
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So, yes, it's a stupid idea [+]. |
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Surprised a town hasn't made the "world's biggest seagull" as a tourist attraction that has utility too. |
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