Natures wonders: bat aerodynamics awesome (Introduction)

by David Turell , Tuesday, December 22, 2015, 21:07 (3040 days ago) @ David Turell

Bats can maneuver better than birds. Their wings are heavier and ears bigger, but all works well:-http://phys.org/news/2015-12-awesomeness.html
Bats, unlike most birds and flying insects, have relatively heavy wings - something that might appear disadvantageous. But a recent study in PLOS Biology by Kenny Breuer and colleagues shows that bats can exploit the inertia of the wings to make sharp turns that would be near-impossible using aerodynamic forces alone.-***-"While evolution has minimised the weight of the largely aerodynamic wings of birds and insects, it seems that bats rely on their wings' mass, retracting them to turn rapidly, as figure skaters retract their heavy arms to spin faster.-"The other bat skill that humans envy - their ability to avoid obstacles while flying at speed in complete darkness - was recently dissected in a PLOS Computation Biology paper by Dieter Vanderelst and colleagues. They used spatial simulations to demonstrate that bats are able to negotiate complex environments without making full 3D reconstructions of their surroundings. All they need is the difference in intensity and travel time of the echo received in their two ears - a pared-down functionality that might help drones deliver your internet orders without hitting a lamppost.-"Sometimes these two prime skills - echolocation and acrobatic flight - seem to be in conflict; echolocation benefits from large ears and complicated "noseleaves," but these features would appear to disrupt the streamlining needed for efficient flight. This PLOS ONE paper, also from Vanderelst and co-authors, put this notion to the test by making 3D models of the heads of seven bat species and sticking them in an air tunnel. Surprisingly, while these facial oddities do increase drag, they also contribute substantially to lift, meaning that they confer little net disadvantage, and so the trade-off between bat abilities is minimal.-Comment: Living organisms are amazingly inventive. Or were they helped?