Since earliest recorded history, and presumably beyond, humans have
always wanted to fly. First attempts involved imitation of winged
creatures around them, and unfailingly ended in disaster. No workable
flying machines have ever looked particularly similar to nature’s
fliers, and today there is little comparison between a top of the range
military chopper and the humble bumblebee, despite similar flight
patterns. In an era in which engineers are increasingly exploiting
designs from nature, understanding this paradox is becoming ever more
important. Dr Jim Usherwood, from the Royal Veterinary College, has
studied the reasons behind these differences in aerodynamics and
concluded that scientists should, in this instance, be more hesitant
before imitating nature. He will be presenting his results on Sunday
6th July at the Society for Experimental Biology’s Annual Meeting in
Marseille [Session A3].
Dr Usherwood believes the reason that
flying creatures don’t look like man made machines is all to do with
the need to flap. "Animals’ wings, unlike propellers, have to keep
stopping and starting in order produce lift (animals have forgotten to
invent propellers, just as they forgot wheels)," he explains. "Think of
vigorous waving, or perhaps exuberant rattling of a cocktail shaker -
this takes a fair amount of power to overcome inertia. So, the idea is
that both wing shape and how wings are used can be understood better if
the effort of flapping is remembered, which explains why vultures don’t
look like gliders, and most winged creatures, from insects to pigeons,
fly so inefficiently."
His research has centred on creatures
as diverse as dragonflies and quails. Currently he is investigating the
compromise winged creatures face between meeting aerodynamic
requirements and overcoming inertia in order to generate lift, by
loading wings of racing pigeons with lead fishing weights. He believes
that lessons from all of these studies lead to the same conclusion. "My
work should act as a reminder to be cautious in copying nature. There
is lots of interest in making MAVs/UAVs (micro/unmanned air vehicles)
that flap, which may present all sorts of advantages in terms of
maneuverability, speed and so on. However, there is a tendancy to
presume that biology is efficient, and I would say that, even at very
small sizes, if you want to hover efficiently, be a helicopter not a
flapper…"
For more information please visit Society for Experimental Biology
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