The Rock Island Argus and daily union. (Rock Island, Ill.) 1920-1923, 1921-10-26
Frederick Haskin's Letter
Leonardo's Wings.
Especial Correspondence Of The Arsus.i

and his lack of Competent scieutie.
technology. He saw very plainly
that a bird had more power in its
wings and breast muscles in nm
portion to its weight, than a ma,
has in his arm and breast muscles
A man has his biggest muscles in
his legs. Leonardo perceived thai
if he was going to compete with fbs
birds he would have to fly with his
legs.
How the Thing Worked.
That was an easy problem for
him. You would have TO look a,
CARRIERS model to see Just how ~
solved it The wings are oparataJ
by pulleys. Leonardo, lying on his
stomach ON the beam, CRASHED han.
dies in each hand, and put his foa.
in a pair of stirrups. Be thrau-ir.-
his arms up he raised the wines
and by kicking backward, like a
swimmer, with both feet, he hrough,
them down and back. Thus nv On.
ing through a sort of horizontal
setting-up exercise, Leonardo couId
flap his wings, as he thought inst
like a bird. He had doubtless
watched the easy Tapping aud sail
ing of the buZzards which hung
about the Italian towns. and figure9
confidently that he could do just AZ
they did.
Leonardo was a good man. lint
like many another good man. not as
good as he thought Il took several
centuries to show just how far he
had miscalculated. Experience with
motor-driven airships has shown
that a 10-horsepower engine is the
least which can fly the weight of
man with any success. 1t wouI5
take at least two horsepower to lift
a man off the ground. And a horse-
power is equal to about eight man
power. Suppose that Leonardo was
about half again as strong as the
average man, he would have had II
be nevertheless about II times as
strong as he was in order to fy
His little device would have af-
forded him splendid exercise, but
no transportation.
Even if he had been Il times as
strong as he was. Leonardo would
probably not have risen an inch. A
bird not only beats its wings with
much greater power, in proportion
to its weight, than d man has, but
it beats them much faster than a
man can move his arms. About $50
wing beats per minute arc neces-
sary to keep a bird in the air. A
man could not possibly do that and
keep it up.
One other point Leonardo over
looked a bird does not really flap
its wings, as it appears to do. The
wing motion of birds is a very COM
plicated thing which scientists have
not yet analysed to their satisfac-
ton, but they believe that the wing
describes approximately a figure
eight in the air. Leonardo could not
have executed such a movement
with his wings.
He never stood a chance TO e.
But if his body did not soar, his
Imagination did. He OWNED that
man was to conquer the air, and
he initiated the conquest.
Paul CARRIER, who has made ds
Vinci's machine visible for us, is
another man of initiative He was
hired by the museum to keep var
ious models in repair-a minor me-
chanicaI task. Having mended
everything mendable, CARRIER looked
the collection over and found that
the model of the first steam engine
was so constructed that it could not
possibly have run. Accordingly he
rebuilt it.
He then decided that the aviation
collection was incomplete, and set
to work. with much IabOTiOUE 70
search. to make it a full record Of
all mans effort to fly. He has now
nearly finished that job, and is at
present working on a couple of Ro-
man catapults to complete the col
lection of military technology.