The Somerset press. [volume] (Somerset, Ohio) 1873-1977, 1881-07-14
Speed at Which Wings are Driven.

The speed at which some wings are
driven is enormous. 1t is occasionally
SO great as to cause the pinions to emit
a drumming sound. To this source the
buzz of the fly, the drone of the bee.si
and the boom of the beetle are to be
referred. When grouse, partridge,
or pheasant, sudd emily springs into the
air, the sound produced by the whirring
of its wings greatly resembles that pro
duced by the contact of steel with the
rapidly revolving stone of the knife
grinder 1t has been estima4ed that the
common fly moves its wings $50 times
per second, e., 19, 800 times per min
ute, and that the butterfly moves its
wings nine times per second or $40 times
per minute. These movements repre-
sent an incredibly high speed even at
the roots of the wings; but the speed is
enormously increased at the tips of the
wings, from the fact that the tips rotate
upon the roots as centres. In reality,
and as has been already indicated, the
speed of the tips of the wings increases
in proportion as the tips are removed
from the axes of rotation, and in pro-
portion as the wings are long. This is
explained on a principle well understood
in mechanics. If rod or wing hinged
at the point be made to vibrate, the
free end of the rod or wing always passes
trough q very much greater space
In a given time than the part nearer the
root of the wing. The progressive in
crease in the speed of the wings. in pro-
portion as the wings become larger, ex-
plains why the wings of bats and birds
are not driven at the extravagant speed
of insect wings. and how the large and
long wings of large bats and birds are
driven more leisurely than the small
and short wings of small bats and birds.
That the wing is driven more slowly in
proportion to its length is proved by
experiment, and by observing the flight
of large and small birds of the same
genus. Thus, large gulls flap their
wings much more slowly than small
gulls; confguration and relative size of
the wings to the body being the same
in both. This is a hopeful feature in
the construction of flying machines, as
there can be no doubt that compare
lively very slow movements will suffice
for driving the long powerful wings re-
quired to elevate and propel flying
machines. The speed of the wing is in
part regulated by the amplitude of the
WluSs linus II tuO WINK OO UAOoO oe
well as long, the beats are necessarily re-
duced IN frequency. This is especially
true of the heron, which is one of the
most picturesque and at the same time
one of the slowest flying birds we have
l have timed the hercn on several oc
| casions, and find that in ordinary
| fight its wings make exactly sixty uT
and sixty down strokes, 4. e., 120 beats
per minute. In the pterodactyl. the
great extinct Saurian, the wing wa
enormously elongated, and in this par
ticular instance probably from fifty t.
sixty beats of the wing per minute suf
feed for fight. Fifty or sixty pulsa
tions of the wing per minute do no
involve much wear and tear OF thu
working parts, and l am strongly o
opinion that artificial flight, If once
achieved, will become comparativel,
safe means of locomotipn as far as tn,
machinery required is concerned
| FrQSer's Magazine.