Tiny machines that fly like insects will soon be a reality. This is predicted by scientists who studied the interesting aerobatics of the butterflies
Tiny machines that fly like insects will soon be a reality. This is predicted by scientists who studied the interesting aerobatics of the butterflies.
Two Oxford researchers placed red admiral butterflies in a specially designed wind tunnel and used high-speed cameras to analyze how these insects move through the air. The result of the experiment, they say, represents a major advance in our understanding of the mechanisms of small-scale flight, and will be of great value to engineers trying to build small aerial vehicles.
There is a demand for this from toy manufacturers and, of course, from the military, said Dr. Adrian Thomas. "We are now moving in the direction where we can build airplanes with a 10-centimeter wingspan that are radio controlled or move independently. They can indeed be used as entertaining toys, but if we put a camera on them they can send them to small places like caves to see what goes on inside them."
Dr. Thomas spent 12 years studying insect aerodynamics. Just building the wind tunnel took over three years. With the help of Dr. Robert Serigli, red admiral butterflies (Vanessa atalanta) were trained to fly freely to and from artificial flowers inside the tunnel. Colored smoke was streamed over the insects' wings to see the interactions between the wings and the air.
The flight of the butterflies was not random, but resulted from the nature of an extensive array of aerodynamic mechanisms," the two wrote in a report in the weekly Nature.
They identified six different ways in which the butterflies flapped their wings and rotated them to stay in the air. The insects moved effortlessly between the different mechanisms, almost like a horse moves between walking, running and jumping, at will, Dr. Thomas said.
The insects flew efficiently and created very small vortices. On another occasion, the butterflies actually created eddies in their wings that helped them soar up. "Insects are known to have a lift capacity 10 times greater than that of airplane wings (per unit of area). Building tiny airplanes that are only scaled-down replicas of real airplanes will never take off from the ground. Only by imitating insects will engineers be able to create micro-aircraft that can take off and fly efficiently." While experiments in miniaturization are progressing rapidly, engineers admit that there is still much to learn from the living world.
From: New York Times
mirage butterflies
15/12/2002
The flight of butterflies in a light wind is not only a model of delicacy: a new study reveals that it is also a great insult to aviation engineers. Scientists from the University of Oxford who examined high-speed digital photographs of free-flying butterflies discovered that the pattern of movement of their wings is tangled and swirling, similar in nature to the movement of smoke.
This is the first time ever that scientists are testing the effect of wing beats of insects in free flight, without any restrictions, on the air around them. The complexity that was discovered was surprising: not only that the "red admiral" butterflies have many different types of wing beats, sometimes even two consecutive wing beats that differ from each other in character. This is different from horses, for example, which change their movement patterns according to their speed, such as when switching from a "trot" to a "canter".
"One insect uses all the aerodynamic methods imaginable," says Dr. Adrian Thomas, one of the two authors of the report on the matter published this weekend in the journal "Nature." , jumping, flipping forwards and backwards, crawling and walking, in no clear order.
Insect movement researcher Dr. Michael Dickinson from the Pasadena Institute of Technology said that although the variety of flight mechanisms and types of wing beats of butterflies were known, the new study is the first evidence of how these mechanisms are applied in free flight.
