There is great popular interest in the problem of soaring, or flying as birds do, without any apparent effort, and also in gliding flights, or descending from a high altitude without the help of a motor.
Wonderful keenness of feeling on the part of an aviator, akin to that remarkable sensitiveness which is exhibited by all blind people, may be highly developed–for an aviator is just like a blind person in the air as far as concerns seeing the eddies, gusts, and currents, which are so dangerous to the balance of the machine–but the ability to advance and go ahead against the wind is as far off as the wireless transmission of power is to-day. It is necessary to have an up-current of air to enable a machine to soar and it is necessary to find where these upward blowing currents are. Any bicycle can coast down hill and a glider is only a coasting aeroplane, and it may be as difficult to find the right air current as to find a hill to coast down on a bicycle.
Great advances will be made in the art of aviation along the lines of training men in the art of handling an aeroplane. No opportunity is so good for this purpose as handling the machine as a glider with the motor shut off, or by practise with a regular gliding machine. Boys will naturally take to gliding, and as a glider was the first form of flying-machine and the easiest to build mechanically, there is every reason why sailing or soaring flights should be thoroughly mastered. The instinct which birds have which enables them to seek out and to utilise the rising currents of air in the wind and so to set and adjust their wings as to enable them to take advantage of these rising currents, is latent in the human mind and can be developed by practice to a point far exceeding that of birds, on account of man's superior intelligence. It is quite possible that some arrangement may be made by which an aviator can see the air and can prepare for or escape conditions that are not favourable to his manœuvres. It is clear that the wind gusts, swirls, and turbulences exist in the air, for they are quite evident when we watch a snowstorm and can see the snowflakes as they float, impelled now in one direction, now another, or as we see dry leaves carried about by a sudden gust of wind, or, even more clearly when over sandy plains we can see the great columns of dust ascending in the center of whirlwinds for hundreds of feet, carrying heavy particles to great heights. It is quite possible that birds can see the air itself by some arrangement of the lenses of their eyes which may either enable them to see the fine dust particles or to so polarise the light that the direction of its vibrations can be determined and the course of flight so changed that an air lane favourable to the path of the bird can be followed and by following out one stream lane among many, which has an upward trend sufficient to counteract the falling tendency, the bird can remain at an equal elevation.
Mr. Orville Wright has clearly demonstrated this to be possible by his experiments lately made at Kitty Hawk, N. C., where he was able to soar for ten minutes over the summit of a sand dune, so delicately adjusting the surfaces of his glider to the up-trend of the wind that he was falling or descending at the same speed that the wind was rising, and thus he seemed to stand still over one spot on the ground. After increasing his descent and approaching the ground, he was able by the delicacy of adjustment of his controls to change the relation in such a manner that the wind rising overbalanced the descending of the machine and he was carried backward and upward to the crest of the hill again, where he remained for a short time before again gliding downward to the level ground below. In the same manner that a boat sails against the wind by the force of the wind blowing against the sail, which is placed at an angle to it and which resists sidewise motion by the pressure of the water against the hull of the boat, a glider with horizontal sails set at the proper angle will also sail into the wind which blows against its surfaces and which makes the path of least resistance a motion forward and slightly descending with relation to the direction of the wind, but which, in the case of an upward moving current of air, may be a path rising in respect to the ground.
The development of skill in this art will come by practice, and young men will follow out the ideas and suggestions of the more experienced until we will have small, light, flexible machines with such sensitive control that, with small motors to enable them to rise or to get from one place to another, much as a bird flaps its wings when necessary to add a little to the power which it gets from the wind itself, or in rising from the ground, will be able to sail around and glide on the strength of the wind for hours at a time.
The clever aviator or real birdman with his keen instinct cultivated to a state of perfection, fitted with polarising glasses possibly, may seek out and utilise the various powers that are present in the air; adjusting his wings so that he will be supported by the upward motion of the air itself where it exists, or, by turning on his motor, moving from one rising column of air to another, upon which he may hover and circle around, steering clear of all those other air lanes which are leading in some other direction.
These glasses, by showing where the air waves are all of one direction, may reveal a current flowing in one way, while they may make great masses of air flowing in some other direction appear as of some other colour, say red, for instance; or, again, in another direction, all may look green, and it will only be necessary to keep where all is pure white.
Entirely new types of machines have been recently constructed in France called "aviettes" and "cycloplanes." These are machines like gliders which are mounted on bicycle wheels and small aeroplanes with wings which have aerial propellers turned by the pedals which drive them along the ground and through the air.
A contest was held in France in June, 1912, for a prize offered by the Puegeot Bicycle Company for the first machine of this type to fly a distance of about forty feet and later a second prize for the first machine to fly over two tapes one meter three feet nine inches apart and four inches high. Both of these prizes were competed for by machines without any motor and driven solely by man power. Over two hundred entries were received by the promoters of the contest, but no one accomplished the flight on that date of the public contest. Three days afterward, however, Gabriel Paulhain succeeded in winning the prize put up for the second test. He flew eleven feet nine inches on his first trial and ten feet nine inches on the second, which was made in the reverse direction.
There seems to be great interest in this form of human flight, which was the original way of attacking the problem of flight itself. When the gasoline motor was perfected mechanical flight followed very quickly and was rapidly developed to a high degree of practicability. It is possible that with encouragement human flight may also become more common than it now is.