An artificial butterfly `created`

Washington: Japanese scientists
have succeeded in building a fully functional replica model --
an ornithopter -- of a swallowtail butterfly, and they have
filmed their model butterfly flying.



Among the various types of butterflies, swallowtails
are unique in that their wing area is very large relative to
their body mass. This combined with their overlapping fore
wings means that their flapping frequency is comparatively low
and their general wing motion severely restricted.
As a result, swallowtails` ability to actively control
the aerodynamic force of their wings is limited and their body
motion is a passive reaction to the simple flapping motion
and not -- as common in other types of butterfly -- an active
reaction to aerodynamics, say the scientists.



To prove that the swallowtail achieves forward flight
with simple flapping motions, the researchers built a lifelike
ornithopter in the same dimensions as the butterfly, copying
the swallowtail`s distinct wing shape and the thin membranes
and veins that cover its wings.
Using motion analysis software, the scientists were
able to monitor the ornithopter`s aerodynamic performance,
showing that flight can be realised with simple flapping
motions without feedback control, a model which can be applied
to future aerodynamic systems.



The findings have been published in the latest edition
of the `Bioinspiration & Biomimetics` journal.



PTI