anes 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.

CHAPTER XIII. PECULIARITIES OF AIRSHIP POWER.

As a general proposition it takes much more power to propel an airship
a given number of miles in a certain time than it does an automobile
carrying a far heavier load. Automobiles with a gross load of 4,000
pounds, and equipped with engines of 30 horsepower, have travelled
considerable distances at the rate