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DualWingGenerator mimics flapping wings to harvest energy


April 2, 2014

Festo has applied the same methodology used in its robotic SmartBird to harvest energy from the wind

Festo has applied the same methodology used in its robotic SmartBird to harvest energy from the wind

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Back in 2011, Festo created a natural-flight mimicking bionic seagull with flapping wings dubbed SmartBird. The company is now looking to apply similar principles in order to convert wind power into electricity with its DualWingGenerator system.

The DualWingGenerator system is comprised of a vertical column supporting a bottom and top pair of "wings" that measure 250 cm (98.4 in) across. The pairs are fitted to separate sliders and then driven up and down as the air flows across the surfaces.

As the wind blows, the wings move in opposing directions, the bottom wings moving upwards as the top move downwards, or vice versa. This motion is then converted into rotary movement inside the column using two timing belts and two free wheels. The rotary force is then transferred to an electricity generator to complete the kinetic to electricity power transformation.

Festo tested the effectiveness of the DualWingGenerator alongside two similar-sized conventional wind turbines. The team says that the system achieved "remarkable outputs compared to small wind power stations," observing a 45 percent fluid-mechanical effectiveness level when used in wind speeds between 4 and 8 meters per second (with the maximum, or Betz' limit being 59.3 percent). The system also demonstrated a marginally higher energy output when used at similarly low wind speeds.

While the output of the DualWingGenerator, like all wind turbines, is related to the strength of the wind, Festo aims to lessen its dependence on the elements with what it describes as intelligent control technology.

This technology is designed to enable the system to self-optimize and adapt to different wind conditions. It involves two servomotors and a sensor built into the central column to dictate the angle, amplitude and frequency of the flapping.

While there is no indication of when or if the system might reach the marketplace, Festo is continuing to develop the technology and cites potential applications such as small scale installations on buildings or for generating compressed air or a water.

Source: Festo

About the Author
Nick Lavars Nick was born outside of Melbourne, Australia, with a general curiosity that has drawn him to some distant (and very cold) places. Somewhere between enduring a winter in the Canadian Rockies and trekking through Chilean Patagonia, he graduated from university and pursued a career in journalism. Having worked for publications such as The Santiago Times and The Conversation, he now writes for Gizmag from Melbourne, excited by tech and all forms of innovation, the city's bizarre weather and curried egg sandwiches. All articles by Nick Lavars

Interesting gull-wing innovation. It has application in Building-mounted linear-axis wind generation. Buildings concentrate wind in density & speed by 12 - 15 times along wall corners & roofline. Such flapping wings can harvest this concentrated wind & so bring the built environment back to ambient air flows. Typically such concentrated wind flows damage buildings & infrastructure (bridges, towers, walkways etc), make many parts of the urban environment unpleasant & destroy wildlife habitat.

Building mounted wind is able to deliver electricity without transmission losses right where the user lives & works. Presently about 50% of electric energy is lost at the rate of 5% per 100 miles of transmission line from central generating sites (nuclear, hydro, most-wind, coal, etc.) including EMF loss & infrastructure capital costs. Such extensive transmission lines massively destroy habitat because of EMF harmful effects to humans & wildlife in wide swaths along 100,000s of miles.

The built environment has massive untapped concentrations of wind, water, compost (soil), fecal (methane & alcohol), urine (nitrogen) & refined materials etc which being thrown away & unharvested are presently damaging & polluting health, wildlife & our enjoyment of our worlds. These complementary sources when harvest both clean up our world as well as provide all & more of the energy human require are the priority of where we must be concentrating our energy harvest investment.

Douglas Jack

The mechanical conversion efficiency is impressive for a small machine, but why anyone would want to end up with reciprocal motion instead of rotary motion is beyond me.


It's beyond me too. Aside from the mechanism issues, the inertial losses have to make this a marginal system. Just because you can do something, doesn't mean it makes any sense.

Allan Bowman

Energy isn't created or destroyed. In this case it is harvested from the wind. Put a flywheel into the system and it will recycle all those rascally rogue reciprocating losses.

I conceived something like this years ago. Shoulda woulda coulda...


If you follow the source link to festo, they have a video showing how it all works. Hands up all those people who used to do that motion going along in their dad's car when they were younger (darn, why didn't I think of this) And don't forget, there's no reason this woulden't work in a river or tidal flow!


Here we are 2014 doing this kind of nutty stuff when Bill Allison hit the Betz limit some 35 years ago in his basement in Grosse Pointe after retiring from FORD. You can read about it in altenergy.com.

In order to extract energy with that efficiency you need.. highly polished front flat faced blades, 10 in a 12 position configuration tilted at 8deg.

It seems as if we have grown into being dolts and no one addressing the solution poperly... the proper configuration is that of a fan as it has been for hundreds of years.

Humanity is not progressing at all despite the HTC and iPhone 5s.

And this is the real problem... fie on this junk.


Island Architect

@Douglas Jack: really great comment. I think these things are going to be retrofitted in cities all over the world and the inventors will make a fortune.


I can think of several reasons for this configuration over turbines and propeller based systems (just referred to as turbines below).

Many communities restrict turbines because of noise both in residential and commercial areas. I suspect these are much quieter. Unfortunately the Festo video does not show wind tunnel information with sound to compare.

Many communities are beginning to restrict do to killing of birds. As I have seen the monster systems in action, I am not sure why birds cannot avoid the slow moving blades or are hurt by them but they cannot and are killed by them. Home systems spin much faster so definitely dangerous to the birds (why not a screen??). This system may be more bird friendly.

It appears it would be easily mounted to buildings, at least buildings where there is a single basic direction for most winds. I am not sure how well this would work if the direction of the winds varies a lot. Maybe the production models would have a large tail like most turbine systems to keep it facing into the wind and adjust out of the wind if the speed gets too high.


Mass produce alone worldwide use or select locales

Stephen Russell

Good grief. Again with the "Bill Allison" myth. You sound like a broken record, Island Architect. Give it up. Nobody believes your propaganda, especially since you've never offered any shred of plausible evidence to back it up. By the way, it's impossible to take seriously a commercial website that was constructed with Microsoft FrontPage and has never heard of CSS margins.


Forget the wind. It is so variable and light. The same technology could be used to harness tidal movements or ocean currents:


The rotational endeavors to tap tides and currents have not fared well, as they have to be set on the seafloor. I suggest they turn this dualwing generator upside down, extend it down from a moored vessel.

Tidal surges and ocean currents are pretty regular. And, with water 1600x more dense than air, you'll get more output per machine-size.

@Paulinator. Don't fret. Check USPTO, and "wind turbines" online. This configuration has been thought of years ago. It is in the refinements that the advances have been made. PS. Patents are sometimes granted, IMO, when it is obvious that the "energy device" has no useful output, compared to the size and cost. But, patented nonetheless.

Scott in California

The question was asked in the comments as to why would one want to use this type of motion instead of rotary. I have thought of this principle for years and always thought this would work along the bottom of relatively slow moving rivers. Large rivers could utilize a multitude of these and in most cases it would not interfere with navigation. They also could work in tides and ocean currents. Being in water presents a different set of problems but the benefits certainly outway the negative side. Using these in narrow channels that have tide action would work because they could be easily reversed as the water changes direction. Because they could lay on the floor of the ocean or river bed and have little impact on the environment makes them very desirable.


I am willing to believe that with the wings working together they can get the efficiency but there is no way that it will be as reliable as a conventional windmill design.

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