The Hickman courier. [volume] (Hickman, Ky.) 1859-current, 1881-03-25
Speed at Which Wings Are Driven.

The speed at which some wings are
driven Is enormous. 1t. Is occasionally
50 great as to cause the pinions to emit
drumming sound. To this source the
buzz of the fly, the drone of the bee, and
the boom of the beetle are TO be referred.
When a grouse, partridge, or pheasant
suddenly springs into the air, the sound
produced by the whirring of its wings
greatly resembles that produced by the
contact of steel with the rapidly revolv-
ing stone of the knife grinder. 1t has
been estimated that the common fly
moves It's wings $50 times per second, 4.
G., 10, 500 times per minute, and that the
butterfly moves its wings nine times per
second, or $40 times per minute. These
movements represent an Incredibly high
speed, even at the root 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 lndl-
Gated, the speed of the tips of the wings
increases in proportion as the tips are
removed from the axis of rotation, and
in proportion as the wings are long. This
Is explained on a principle well under
stood in mechanics. If rod or wing
hinged at one point be made TO Ylbrate,
the free end of the rod or wing always
passes through q very much greater
space in given time than the part
nearer the root of the wing. The pro-
Gressive increase in the speed OF the
wings, IN proportion as the wings be-
come larger, explains why the wings OF
bats and birds are not driven at the ex-
travagant 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 ny 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; the 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 debut that comparatively very
slow movements will suffice for driving
the long powerful wings required to ele-
vate and propel flying machines. The
speed OF the wing is in part regulated by
the amplitude of the wing. Thus IT the
wing be broad as well as long, the beats
are necessarily reduced in frequency.
InlS - especially true OF Ine neron,
which is one of the most picturesque
and at the same time one of the slowest
flying birds we have. 1 have timed the
heron on several occasions, and find that
in ordinary fight its wings make exactly
sixty up and sixty down strokes, 4. e.,
100 beats per minute. In the ptero-
dactyl, the great extinct Saurian, the
wing was enormously elongated, and In
this particular instance probably from
so to so beats of the wing per minute
sufliced for fight. Fifty or sixty pulsa-
tions of the wing per minute do not in
yolve much wear and tear of the working
parts, and | am strongly of opinion that
artificial flight, if once achieved, will
become q comparatively safe means of
locomotion as far as the machinery re-
quired is concerned. .-Eraser's Aagd-
zine