Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Aerodynamic performance of the swift unravelled

26.04.2007
A swift adapts the shape of its wings to the immediate task at hand: folding them back to chase insects, or stretching them out to sleep in flight. Ten Dutch and Swedish scientists, based in Wageningen, Groningen, Delft, Leiden, and Lund, have shown how 'wing morphing' makes swifts such versatile flyers.

Their study, published as cover story in Nature on April 26, proves that swifts can improve flight performance by up to three-fold, numbers that make 'wing morphing' the next big thing in aircraft engineering.

Swifts spend almost their entire life in the air. During flight, they continually change the shape of their wings from spread wide to swept back. When they fly slowly and straight on, extended wings carry swifts 1.5 times farther and keep them airborne twice as long. To fly fast, swifts need to sweep back their wings to gain a similar advantage.

Economic turns

During the summer, we can observe swifts circling above town squares, where they catch up to 20.000 insects a day. Swift can triple their efficiency by turning with their wings stretched out. When chasing rivals and flying insects, swifts also want to make their turns fast and tight. However, in fast and diving turns, the load on the wings easily reaches more than four times the swift's body weight. So in extreme turns, swifts need to sweep back their wings or else risk breaking them.

Night's rest

Swifts do not land to roost, but spend the night at 1.5 km above the ground. To measure their flight speed, Swedish scientists used radar. They found that swifts let the air blow past their wings at 8 to 10 m/s (29-36 km/h). At these air speeds, swift wings deliver maximum flight efficiency. For the swift that means more gliding and less flapping to maintain altitude.

The scientists figured all this out when they measured just how much lift and drag a swift wing generates. The wings were tested to their limit in a windtunnel at speeds of up to 108 km/h (30 metres per second).Scientists compared extended and swept wings, and learnt that flying slowly with extended wings gives swifts maximum flight efficiency. But swept wings deliver a better aerodynamic performance for flying fast and straight. Swept wings are also better for fast and tight turns; but this time swept wings are better because they do not break as easily as extended wings.

Airplanes

Morphing wings are the latest trend in aviation. The best wing shape to save fuel costs depends on flight speed. In 2003, birds inspired NASA to design a revolutionary "morphing wing" aircraft. Also so-called micro-aircraft, which are the size of a bird, begin to exploit the benefits of varying wing shape. These tiny flyers, equipped with cameras and sensors to assist in surveillance and espionage, imitate faithfully the flight behaviour and appearance of birds. In an ongoing project, students at Delft University cooperate with scientist at Wageningen, to make such a small airplane fly like a swift.

The swifts for this study had been brought in dead or dying to seven Dutch bird sanctuaries. Swifts, when forced to land on the ground, cannot take off by themselves and will starve unless a kind and timely passer-by throws them in the air. Swifts are the most aerial of birds. They migrate annually from South Africa to Europe. Over their lifetime, swifts cover 4.5 million kilometres, a distance equal to six round trips to the moon or 100 times around the Earth. At day, swifts hunt insects; at night they 'roost' in flight. Swifts even mate in the air and land only lay their eggs, in nests tucked away into crevices of walls and cliffs. Swifts are not related to swallows. They are family of another well-known aerial acrobat, the hummingbird.

Jac Niessen | alfa
Further information:
http://www.wur.nl

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>