`Pterosaurs were soaring fliers and light landers`

Pterosaurs were light and fragile creatures best suited for catching rising air to soar.

Last Updated: Nov 25, 2010, 08:58 AM IST

London: Pterosaurs, the largest known flying
reptiles that roamed the earth some 65 million years ago, were
light and fragile creatures best suited for catching rising
air to soar, a new study has found.

The ancient reptiles that existed at the time of
dinosaurs were incredibly at their best in flying high and
landing slowly, found the new study.

"I wanted to understand how these animals flew, and as an
engineer one of the first things you do is you measure the
performance of the wing, and I realised no one had ever done
that before," said Colin Palmer, a researcher in paleontology
at England`s University of Bristol.

According to Palmer, a former engineer who was once
involved in yacht design, pterosaurs had wings composed of a
flexible membrane reinforced with fibbers, and wingspans of up
to 33 feet (10 meters), LiveScience reported.

He said a pterosaur wing has the aerodynamic
characteristics of the mainsail of a sailboat, with the
equivalent of a ring finger forming the leading edge of much
of the wing, but with no additional support for the membranous
wing other than its attachment at the ankle.

Although scientists know from fossils that the wing was
composed of a membrane, details were missing from the complete
picture of wing anatomy, such as how far back the membrane
extended behind the wing bone, Palmer said.

It is also not clear how much the wings curved in the
plane parallel to the body, an aerodynamic property called
camber.

For his research, Palmer tested a series of simplified
cross-sections simulating possible shapes for the wing in a
wind tunnel -- a research tool used to study the movement of
air as it passes around objects.

The resulting data indicated that pterosaurs experienced
more drag than anticipated, and confirmed the previous theory
that they were slow fliers.

"In order to fly at their best, they had to have quite a
lot of camber in their wing membrane," Palmer said. "This
means they fly at their best when they fly slowly."

This, in turn, indicates that they were best suited for
calm tropical air, riding rising columns of air over
coastlines and elsewhere.

While pterosaurs came in many species and in many sizes,
down to that of a blackbird, Palmer geared his tests for a
generic pterosaur with a wingspan of about 6 meters (19.7
feet).

His work is published in the journal the Proceedings of
the Royal Society B.

PTI