HOW TO USE THE MACHINE.
It is a mistaken idea that flying machines must be
operated at extreme altitudes. True, under the impetus
of handsome prizes, and the incentive to advance scientific
knowledge, professional aviators have ascended to
considerable heights, flights at from 500 to 1,500 feet being
now common with such experts as Farman, Bleriot,
Latham, Paulhan, Wright and Curtiss. The altitude
record at this time is about 4,1
5 feet, held by Paulhan.
One of the instructions given by experienced aviators
to pupils, and for which they insist upon implicit obeyance, is:
"If your machine gets more than 30 feet high,
or comes closer to the ground than 6 feet, descend at
once." Such men as Wright and Curtiss will not tolerate
a violation of this rule. If their instructions are
not strictly complied with they decline to give the offender
Why This Rule Prevails.
There is good reason for this precaution. The higher
the altitude the more rarefied (thinner) becomes the air,
and the less sustaining power it has. Consequently the
more difficult it becomes to keep in suspension a given
weight. When sailing within 30 feet of the ground sustentation
is comparatively easy and, should a fall occur,
the results are not likely to be serious. On the other
hand, sailing too near the ground is almost as objectionable
in many ways as getting up too high. If the craft
is navigated too close to the ground trees, shrubs, fences
and other obstructions are liable to be encountered.
There is also the handicap of contrary air currents
diverted by the obstructions referred to, and which will
be explained more fully further on.
How to Make a Start.
Taking it for granted that the beginner has familiarized
himself with the manipulation of the machine, and especially
the control mechanism, the next thing in order
is an actual flight. It is probable that his machine will
be equipped with a wheeled alighting gear, as the skids
used by the Wrights necessitate the use of a special
starting track. In this respect the wheeled machine is
much easier to handle so far as novices are concerned
as it may be easily rolled to the trial grounds. This,
as in the case of the initial experiments, should be a
clear, reasonably level place, free from trees, fences,
rocks and similar obstructions with which there may be
danger of colliding.
The beginner will need the assistance of three men.
One of these should take his position in the rear of the
machine, and one at each end. On reaching the trial
ground the aviator takes his seat in the machine and,
while the men at the ends hold it steady the one in the rear
assists in retaining it until the operator is ready. In the
meantime the aviator has started his motor. Like the
glider the flying machine, in order to accomplish the
desired results, should be headed into the wind.
When the Machine Rises.
Under the impulse of the pushing movement, and assisted
by the motor action, the machine will gradually
rise from the ground--provided it has been properly
proportioned and put together, and everything is in working
order. This is the time when the aviator requires
a cool head, At a modest distance from the ground use
the control lever to bring the machine on a horizontal
level and overcome the tendency to rise. The exact
manipulation of this lever depends upon the method of
control adopted, and with this the aviator is supposed
to have thoroughly familiarized himself as previously
advised in chapter XI.
It is at this juncture that the operator must act
promptly, but with the perfect composure begotten of
confidence. One of the great drawbacks in aviation by
novices is the tendency to become rattled, and this is
much more prevalent than one might suppose, even
among men who, under other conditions, are cool and
confident in their actions.
There is something in the sensation of being suddenly
lifted from the ground, and suspended in the air that is
disconcerting at the start, but this will soon wear off if
the experimenter will keep cool. A few successful flights
no matter how short they may be, will put a lot of
confidence into him.
Make Your Flights Short.
Be modest in your initial flights. Don't attempt to
match the records of experienced men who have devoted
years to mastering the details of aviation. Paulhan,
Farman, Bleriot, Wright, Curtiss, and all the rest of
them began, and practiced for years, in the manner here
described, being content to make just a little advancement
at each attempt. A flight of 150 feet, cleanly and
safely made, is better as a beginning than one of 400
yards full of bungling mishaps.
And yet these latter have their uses, provided the
operator is of a discerning mind and can take advantage
of them as object lessons. But, it is not well to invite
them. They will occur frequently enough under the
most favorable conditions, and it is best to have them
come later when the feeling of trepidation and uncertainty
as to what to do has worn off.
Above all, don't attempt to fly too high. Keep within
a reasonable distance from the ground--about 25 or 30
feet. This advice is not given solely to lessen the risk
of serious accident in case of collapse, but mainly because
it will assist to instill confidence in the operator.
It is comparatively easy to learn to swim in shallow
water, but the knowledge that one is tempting death in
deep water begets timidity.
Preserving the Equilibrium.
After learning how to start and stop, to ascend and
descend, the next thing to master is the art of preserving
equilibrium, the knack of keeping the machine perfectly
level in the air--on an "even keel," as a sailor would
say. This simile is particularly appropriate as all aviators
are in reality sailors, and much more daring ones
than those who course the seas. The latter are in craft
which are kept afloat by the buoyancy of the water,
whether in motion or otherwise and, so long as normal
conditions prevail, will not sink. Aviators sail the air
in craft in which constant motion must be maintained in
order to ensure flotation.
The man who has ridden a bicycle or motorcycle
around curves at anything like high speed, will have a
very good idea as to the principle of maintaining equilibrium
in an airship. He knows that in rounding curves
rapidly there is a marked tendency to change the direction
of the motion which will result in an upset unless
he overcomes it by an inclination of his body in an opposite
direction. This is why we see racers lean well
over when taking the curves. It simply must be done
to preserve the equilibrium and avoid a spill.
How It Works In the Air.
If the equilibrium of an airship is disturbed to an
extent which completely overcomes the center of gravity
it falls according to the location of the displacement.
If this displacement, for instance, is at either end the
apparatus falls endways; if it is to the front or rear, the
fall is in the corresponding direction.
Owing to uncertain air currents--the air is continually
shifting and eddying, especially within a hundred feet or
so of the earth--the equilibrium of an airship is almost
constantly being disturbed to some extent. Even if this
disturbance is not serious enough to bring on a fall it
interferes with the progress of the machine, and should
be overcome at once. This is one of the things connected
with aerial navigation which calls for prompt,
Frequently, when the displacement is very slight, it
may be overcome, and the craft immediately righted by
a mere shifting of the operator's body. Take, for illustration,
a case in which the extreme right end of the
machine becomes lowered a trifle from the normal level.
It is possible to bring it back into proper position by
leaning over to the left far enough to shift the weight
to the counter-balancing point. The same holds good as
to minor front or rear displacements.
When Planes Must Be Used.
There are other displacements, however, and these are
the most frequent, which can be only overcome by manipulation of
the stabilizing planes. The method of procedure
depends upon the form of machine in use. The
Wright machine, as previously explained, is equipped
with plane ends which are so contrived as to admit of
their being warped (position changed) by means of the
lever control. These flexible tip planes move simultaneously,
but in opposite directions. As those on one end
rise, those on the other end fall below the level of the
main plane. By this means air is displaced at one point,
and an increased amount secured in another.
This may seem like a complicated system, but its
workings are simple when once understood. It is by
the manipulation or warping of these flexible tips that
transverse stability is maintained, and any tendency to
displacement endways is overcome. Longitudinal stability
is governed by means of the front rudder.
Stabilizing planes of some form are a feature, and a
necessary feature, on all flying machines, but the methods
of application and manipulation vary according to the
individual ideas of the inventors. They all tend, however,
toward the same end--the keeping of the machine
perfectly level when being navigated in the air.
When to Make a Flight.
A beginner should never attempt to make a flight
when a strong wind is blowing. The fiercer the wind,
the more likely it is to be gusty and uncertain, and the
more difficult it will be to control the machine. Even
the most experienced and daring of aviators find there
is a limit to wind speed against which they dare not
compete. This is not because they lack courage, but
have the sense to realize that it would be silly and useless.
The novice will find a comparatively still day, or one
when the wind is blowing at not to exceed 15 miles an
hour, the best for his experiments. The machine will be
more easily controlled, the trip will be safer, and also
cheaper as the consumption of fuel increases with the
speed of the wind against which the aeroplane is forced.