Their grace and elegance in spreading their wings and fly-off, has
been a reason of deep thinking for the man who seeks answers.Since the
Ancient Greece time, the great philosophers of that era reflected on
the fact thathow it was possible for some creatures to rise up in the
sky and cover amazing distances with such a great harmony. A famous
greek mythologylegend states that Icarus was the first man to fly.
The attempts for man to fly has been unsuccesful until December 17th,
1903 when Wright Brothers managed to accomplish the fateful task so
much desired by the men of all the times. This first flight lasted 61
meters at a speed of about 43 km/h using a rudimentary airplane built
by the same two brothers. From that day, the technological advance has
allowed theimprovement in an exceptional way of that first rudimentary
attempt to imitate the bird's flight. Today, we can see airplanes of
different sizes and shapes fly in the skies of the Earth like birds.
As probably everyone of us know, the airplanes' wing perfectly imitate
those of the birds. Like the bird's wings, those of the airplanes do
have the upper part curved and not just flat. In this way, when
engines generate a thrust, that particular shape makes possible for
the air that flows in the upper part of the wing travel faster than
that in the lower part. As a consequence, avertical thrust is
generated which allows to overcome the gravity force and in this way
theplane can lift up and fly like a bird.
That description presented above is a semplified one, since a lot of
complex mathematics and physicsis need to acurately describe the
dynamic of flight, but that allows to grasp the simple principle that
is behind the technology that everyone or almost of ushave personally
experimented. But man didn't stop here. He wanted again to draw
inspiration from the masters of flight which are the birds. Big birds
like eagles, hawks, vultures etc. do have wings with a particular
structure with respect tothe many other varieties of birds. At their
wing's extremities, they have some "winglets" of different sizes which
allows to eliminate the vertical vortex created around the wing and
this fact can reduce the drag experimented by the wing (fig. 2, 3).
Indeed, during the flightthese winglets curve-up almost vertically
making the wing non-planar and so greatly reduce the drag. With such a
particular wing structure, these big birdscan fly with the minimum
effort and without consuming a lot of energy. Only recently man has
realized this fact and could "copy" and implement this astonishing
detail for hisown purposes. Now, a great number of air companies equip
their airplanes with this apparently simple device(fig. 1,4). Just
like those of the birds, these man-made winglets make possible to
eliminate vortexes (fig. 1) that are created around the plane's wings
and with the consequence that:
-the airplane's fuel consumption is reduced so it also pollutes less
- using these winglets, the airplane needs smaller wings to generate
the same vertical lift compared with that which doesn't have them. In
this way, one can build smaller airplanes that consume less fuel and
need smaller airports
As we have seen till now,the birds are perfect flying machines,
designed in the most efficient and perfect possible way. From
thesemarvelous creatures, man has been able to draw his inspiration
andbuild his own flying machines and realize his biggest dream: to fly
likea bird. With the discoveries about these winglets, Allah has
showed us again His infinite power and wisdom.
"Do they not see the birds controlled in the atmosphere of the sky?
None holds them up except Allah . Indeed in that are signs for a
people who believe. " (Surat An-Nahl, 79)
"Haven't they looked at the birds above them, with wings outspread and
folded back? Nothing holds them up but the All-Merciful. He sees all
things." (Qur'an, 67: 19) - - ▓███▓ Translator:->
http://translate.google.com/m/ ▓███▓ - -
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