Page 14 - Engineering in Nature

Engineering in Nature

The Incomparable Design in Living Things
Scientists have carried out various studies on how owls are able to
approach their prey so silently in the still of night without making
themselves heard. Research carried out under the U.S. Air Force's
"Ghost Plane Project" revealed these birds' faultless wing design.
The feathers of other bird species have sharp edges, while owls'
feathers do not. This enables the animal to fly and hunt at night, com-
pletely silently.
According to a statement by scientists at NASA's Langley
Research Center, the soft edges of an owl's feathers prevent air turbu-
lence, that in turn prevents noise. When looking for ways of making
ghost planes fly through the sky without being detected, military de-
signers copied the owl feather's structure. 1
At the world's busiest airports, planes land and take off roughly
every two to three minutes during the day. Airway traffic of this den-
sity is controlled by leaving between planes a distance of 4 to 5 km (2

"Ghost" planes invisible to modern radar have been manufactured, but the noise from
all low-flying planes can be heard from hundreds of meters away. Scientists are trying
to solve this problem by studying the silent flight of owls and adapting their wings' de-
signs.

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