The Osceola times., 1881-06-11
WING SPEED,
Some Interesting Facts About tho Way
That Birds Fly.
Frazorfs MaUaxiua


Fazers Magazine.
The speed at which some wings are
driven is enormous. 1t is occasionally
so great as TO cause the pinions 10 emit a
drumming sound. To this source the
buzz of the fly, the drone of the bee and
the boom Of the beetle are to be refer
red. When a grouse, partridge or pleas
ant 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
revolving stone OF the knife-grinder. 1t
has been estimated that the common fly
moves its wings $50 times per second, i.
e. 1880 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
sp' ed even to the roots: but the speed is
enormously increased at the tips of the
wings, from the fact that the tips rotate
upon the roots as centers. In reality,
and as it has been already indicated, the
speed at the tips of the wings increases
in proportion as the tips are removed
from the axes of rotation, and in proper
ton as the wings are long. This is ex-
planned on the principle well understood
IN mechanics. IL rod or wing hinged
at one point be made to vibrate, the free
end Of the rod or wing always passes
through very much greater space in
gwen time than the part nearer the root
OF the wing. The progressive increase
IN the speed OF the wings in proportion
as the wings become larger explains why
the wings of bats and birds are not
driven at the extravagant speed Of in
sect 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 genius. Thus
large gulls flap their wings much more
slowly than small gulls; the confgura-
ton 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 comparatively very slow
movements will suffice for driving the
long, powerful wings required to elevate
and propel flying machines. The speed
of the wing is in part regulated by the
ampleture of the wing. Thus, if the wing
be broad as well as long, the beats are
necessarily reduced 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. ! have timed the heron on
several occasions, and find that in ordin-
airy flight its wings make exactly sixty
up and sixty down strokes-i. @, l20
beats per minute. In the pterodactyl,
the great extinct Saurian, the wing was
enormously elongated, and in this par
ticular instance probably from fifty to
sixty beats of the wing per minute
sntiiced for flight. Fifty or sixty pulsa-
tions of the wing per minute do not in
volve much wear and tear of the work
ing parts, and am strongly of the opin-
ion that artificial flight, if once achieved
will become comparatively safe means
of locomotion, az far as the machinery
required is concerned.