The Appeal. [volume] (Saint Paul, Minn. ;) 1889-19??, 1912-11-09
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moving horizontally or upward incorporation u
the surface of the planes, should be falling then
the support of the flying machine is suddenly
diminished to that extent, and the aeroplane
drops Again, If the aviator is travelling against
stratum of wind of a definite speed and then
purposely descends, reaching an air belt OF lower
speed altered direction, these changes may re-
duce the force of the air striking the surfaces
of his planes, and this drop in pressure may
cause his machine to fall speedily earthward'
This is another proof of course, of the imaginary
vacant places in the air.
We must bear in mind that the problem OF
the flying machine is quite distincG from that or
the balloon. The balloon floats because it Is
either lighter than the air it displaces-when 1t
rises-or remains at fixed altitude because there
is perfect balance between it's weight and that
of the air which it thrusts aside It remains
aloft whether drifting with the wind or being
driven by motor. The heavierthan-air flying
machine, on the other hand, is sustained in flight
only so long as its movement forward arouses
sufficient opposition on thezpart to lift
or to sustain it. When the propellers cease to
revolve the aeroplane starts earthward, and dis
aster can be avoided only by volplaning or per-
forming a sweeping spiral descent. maneuver
of this sort is nothing less than
modified drop. The safety of the aeroplane,
therefore, when in midair, depends upon the nice
balancing of the machine and the proper equaliz-
ing of pressure upon the planes. Eddies in the
air or any other disturbance which will bring
the aeroplane into conflicting atmospheric belts
or zones will imperil the stability of the ma
chine and the life of the aviator unless he be
watchful and there some of these con.
ditions against which he cannot sufficiently
guard
The flying machine in going ahead, hits the
air succession of rapid blows and by this
causes an area of compression which is equal in
the force of its reaction to the weight of the
flying machine. The fact Of it u.s. this compress
sion actually affects a volume of air equal in
foot of atmospheric air weighs only .08 of
pound at the freezing point, little figuring will
show how wide is the area upon which the avia-
tor must draw for his support.
What happens then when the flying machine
has moved onward and the atmosphere tries to
resume it's normal state? The reaction is like
the release Of a spring, and the air acquires
vibratory motion greatest in vertical direction
akin to the prolonged holdings of partly
water-soaked log after being hit blow But this
is not all.
We are living at the bottom of an ocean of
air, and living in that region of the at
mosphere where it is densest The natural ten
dency for the atmosphere is to fall when not
made lighter, by heat and caused to rise. An
aeroplane shooting through this lower belt is
substantially knocking out the foundations from
beneath the atmospheric columns reaching many
thousands of feet heavenward, and we have in
the air virtual duplication of our bobbing log
many, many times repeated at every stage Of
the onward movement of the flying machine and
the successive reactions of ;theecompressed air,
which has momentarily sustained that mechan-
1cal fight. Isn't it clear, then, that an aviator
when passing above or below another aviator
is either stumbling into air holes thus created
producing similar condition to menace his
nearby fellow? The airman advancing at the
greater speed will produce the wider area of dis
turbance and within any prescribed limit the
more dangerous reaction.
The flying machine when aloft is in a state of
decidedly delicate equilibrium, otherwise the.
mere fexing of wing tips would be incapable of
correcting its horizontal position Any change
of pressure at the extremity of it's wings is equiva
lent to adding reducing the weight at the one
or the other tip, and upsetting movement is
started. It is quite probable that even though
one aeroplane may be full hundred feet above
or below another. still the greater speed of the
overtaking machine may cause sufficient down
ward movement the part of the air to over
weight suddenly one wing of the other machine.
This is certainly what happened in the case of
Lieutenant Briez. Mile Dutrieu and a number of
others.
The task set the investigators is that of find
Ing how wide Is the region of agitation created
by flying machine in flight, and, with this
knowledge, to prescribe the proper distances
which aviators must observe when approaching
one another.
Fortunately, the flying machine Is now studied
in the laboratory, and recent progress in expert
mental aerodynamics Is doing much toward
clearing the way for safe advance in the near
future but the public must be patient and It
must realize that flying is full of hazards at
best and we are really scarcely much more than
upon the Threshold Of this wonderful science.