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.
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.
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.
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
Amputees can learn to control a robotic arm with their minds
28.11.2017 | University of Chicago Medical Center
The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences