microrobert
09-18-2013, 10:09 AM
Dinosaur in a wind tunnel tests feathered flight
http://www.youtube.com/watch?v=iFR2WW2Wp-I
A life-sized model of a dinosaur has been suspended in a wind tunnel to help test how feathered dinosaurs might have taken to the air roughly 125 million years ago.
The results suggest that the small, four-winged creatures of the genus Microraptor would have been efficient gliders even without feathers. This supports the idea that plumage might not have evolved for flight but may instead have been a key aspect of sexual-selection displays (http://www.newscientist.com/article/dn22428-dinosaurs-may-have-evolved-feathers-for-courtship.html).
The creatures lived during the early Cretaceous period and are a genus of dromaeosaurs – two-legged predatory dinosaurs that are related to birds. The first microraptor with preserved feathers (http://www.newscientist.com/article/dn3298-fourwinged-dinosaur-makes-feathers-fly.html) was unearthed in China in 2003, showing long plumes on all four of its limbs. This set off a firestorm of debate (http://www.newscientist.com/article/dn23275-four-wings-bad-two-wings-better--for-early-birds.html) about how the animal might have moved through the air, since this could offer clues to how bird ancestors first put their limbs to the task of gliding and flapping.
Model flyer
One of the fiercest points of contention was microraptors' leg positioning: were the legs splayed parallel to the forearms to form two pairs of wings, like a biplane (http://www.newscientist.com/article/dn11007-did-the-dinosaurs-invent-biplane-technology.html)? Or were they folded beneath its body, like the legs of modern raptors catching prey?
"For years scientists thought microraptors could fly but weren't sure how," says Gareth Dyke (http://www.southampton.ac.uk/oes/about/staff/gjd1n10.page) at the University of Southampton in the UK. For their tests, Dyke and his colleagues fashioned the first full-scale, anatomically accurate model of a microraptor from balsa wood, aluminium and mallard feathers. The model, dubbed Maurice, weighs in at about half a kilogram and has a 60-centimetre wingspan.
Maurice was suspended in a wind tunnel by piston-tipped poles, which allowed the team to alter the legs and tail mid-flight (see video, above).
The model was then exposed to gusts of up to 20 metres per second. Airflow analysis suggests that the dinosaur probably could have switched between its possible leg configurations mid-air, and that either one would have allowed it to glide in roughly the same way.
Squirrely dino
Overall, microraptors would have been most stable in a slow glide that is less aerodynamically efficient but would have resulted in minimal height loss and longer flight distances. That kind of movement would have been ideal for an animal that combined arboreal and ground-based foraging by scampering up trunks and gliding between trees, like a modern-day flying squirrel, says Dyke.
What's more, Maurice's flight capabilities did not change when his feathers were removed. "The most important thing for this dinosaur was maximising wing surface rather than the presence of feathers," says Dyke.
"That's a key thing, because for many years scientists thought feathers were unique to birds as a great adaption for generating flight. But it seems almost 100 per cent certain that feathers evolved for something else. We just have to figure out what for."
Dinosaur in a wind tunnel tests feathered flight - life - 18 September 2013 - New Scientist (http://www.newscientist.com/article/dn24218-dinosaur-in-a-wind-tunnel-tests-feathered-flight.html#.Ujl6nyRV3cc)
http://www.youtube.com/watch?v=iFR2WW2Wp-I
A life-sized model of a dinosaur has been suspended in a wind tunnel to help test how feathered dinosaurs might have taken to the air roughly 125 million years ago.
The results suggest that the small, four-winged creatures of the genus Microraptor would have been efficient gliders even without feathers. This supports the idea that plumage might not have evolved for flight but may instead have been a key aspect of sexual-selection displays (http://www.newscientist.com/article/dn22428-dinosaurs-may-have-evolved-feathers-for-courtship.html).
The creatures lived during the early Cretaceous period and are a genus of dromaeosaurs – two-legged predatory dinosaurs that are related to birds. The first microraptor with preserved feathers (http://www.newscientist.com/article/dn3298-fourwinged-dinosaur-makes-feathers-fly.html) was unearthed in China in 2003, showing long plumes on all four of its limbs. This set off a firestorm of debate (http://www.newscientist.com/article/dn23275-four-wings-bad-two-wings-better--for-early-birds.html) about how the animal might have moved through the air, since this could offer clues to how bird ancestors first put their limbs to the task of gliding and flapping.
Model flyer
One of the fiercest points of contention was microraptors' leg positioning: were the legs splayed parallel to the forearms to form two pairs of wings, like a biplane (http://www.newscientist.com/article/dn11007-did-the-dinosaurs-invent-biplane-technology.html)? Or were they folded beneath its body, like the legs of modern raptors catching prey?
"For years scientists thought microraptors could fly but weren't sure how," says Gareth Dyke (http://www.southampton.ac.uk/oes/about/staff/gjd1n10.page) at the University of Southampton in the UK. For their tests, Dyke and his colleagues fashioned the first full-scale, anatomically accurate model of a microraptor from balsa wood, aluminium and mallard feathers. The model, dubbed Maurice, weighs in at about half a kilogram and has a 60-centimetre wingspan.
Maurice was suspended in a wind tunnel by piston-tipped poles, which allowed the team to alter the legs and tail mid-flight (see video, above).
The model was then exposed to gusts of up to 20 metres per second. Airflow analysis suggests that the dinosaur probably could have switched between its possible leg configurations mid-air, and that either one would have allowed it to glide in roughly the same way.
Squirrely dino
Overall, microraptors would have been most stable in a slow glide that is less aerodynamically efficient but would have resulted in minimal height loss and longer flight distances. That kind of movement would have been ideal for an animal that combined arboreal and ground-based foraging by scampering up trunks and gliding between trees, like a modern-day flying squirrel, says Dyke.
What's more, Maurice's flight capabilities did not change when his feathers were removed. "The most important thing for this dinosaur was maximising wing surface rather than the presence of feathers," says Dyke.
"That's a key thing, because for many years scientists thought feathers were unique to birds as a great adaption for generating flight. But it seems almost 100 per cent certain that feathers evolved for something else. We just have to figure out what for."
Dinosaur in a wind tunnel tests feathered flight - life - 18 September 2013 - New Scientist (http://www.newscientist.com/article/dn24218-dinosaur-in-a-wind-tunnel-tests-feathered-flight.html#.Ujl6nyRV3cc)