Newsgroup: it.arti.poesia
Titolo: esegesi d'un miracolo(inglese)

Secondo alcuni autorevoli testi di tecnica di aeronautica, il 
calabrone non può volare, a causa della forma e del peso del proprio 
corpo in rapporto alla superficie alare.
               Ma il calabrone non lo sa e perciò continua a volare.
                                            Igor Sikorsky
(puo' che essere che per la citazione io sia debitore al sito di 
bobregular, non mi ricordo piu' dove l'abbia presa: sul suo sito non 
c'e' piu')
A robotic fruit fly 100 times larger than a real one has helped solve 
the
mystery of how flies fly, scientists say.
The bumblebee paradox, which confounded scientists in 1930 when it was
proven that flies' wings are too weak to get the bugs off the ground, 
was
supposedly solved five years ago by Charles Ellington, a renowned 
Cambridge
entomologist. But his theory was wrong, said insect flight expert 
James
Birch, whose team in the department of integrative biology at 
University of
California, Berkeley, found a better solution. It appears in the 
current
issue of Nature.
The team used data from the sensors on Robofly, a pair of fibreglass 
wings
that flap in a tank of mineral oil to mimic how thick air feels to a 
fruit
fly.
The researchers demonstrated that a whirl of air like a "little 
tornado"
sits on top of the wing. This whirl, called a vortex, creates a region 
of
low pressure that sucks the fly upward.
In theory, the vortex should quickly grow too strong for the wing and 
peel
off, but it is held mysteriously stable on the wing, Dr. Birch said.
As flies flap, their wings hit oncoming air at a high angle, 45 
degrees
compared with 10 degrees on most airplanes. The deflected air creates 
an
upward force and a downwash of air.
This downwash lowers the angle at which the next flap strikes oncoming 
air,
diminishing the strength of the vortex and keeping it in place, Dr. 
Birch
said. Without this stabilizing effect, Mr. Birch says, the vortex 
would fall
away, the lift would be lost and the fly would plummet.
The vortex is stabilized and the fly is kept aloft by this effect of 
the
previous strokes, "the ghosts of vortices past," Dr. Birch said.
Dr. Ellington's debunked theory had likened flies to such delta wing
airplanes as the Concorde, which keep their vortex in place with air 
flowing
along the wing.
Robofly's 25-centimetre-long, fibreglass wings are powered by three 
motors
that allowed Dr. Birch to accurately recreate the wing movements of a 
fruit
fly.
"We can create any kind of movement or kinematic pattern that you can 
think
of," he said. "That's something that Charlie [Ellington] did not have, 
and
really it's why we've been able to jump ahead."
Dr. Birch is collaborating with engineers to make a "micro-mechanical 
flying
insect" which could have applications for tiny flapping robots that 
could be
used for search and rescue or espionage.
-- 
io sto macchinando per entrare nel presepe
manganelli

 manganelli
io invece sto già facendo il presepe perché Gesù mi regali la macchina :-)
manganellate a tutti....

 manganelli
io sto già facendo il presepe perché Gesù mi porti una nuova macchina :-)
BoB

                                             Igor Sikorsky
E' l'iscrizione posta all'ingresso drlla facoltà di ingegneria aereospaziale
(?) di CAmbridge o di un'altra rinomata universtà inglese
a memoria però era dedicata al maggiolino


turbamento. :)
ciao
quinlan


ab origine.
ma non capisco se l'hai mai avuta sulle tue pagine oppure no: in tal 
caso l'ho letta su un altro sito.



eh, ma e' interessante il fatto che questo turbamento viene rovinato 
dalle spiegazioni dell'articolo inglese...
forse un giorno si spieghera' persino il volo d'una poesia :)
p.s. film da vedere?



grazie, sara' questione di traduzione...bug vuol significare pure 
difetto di programmazione...:)


manganelli
ciao 
quinlan
ma i bombi sono i calabroni?