Above all, don't attempt to fly too high. Keep within a reasonable distance from the ground--about 25 or 30feet. 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, intelligent action.
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.
