XVIII.—FLYING MACHINES OF THE PRESENT, THEIR DEFECTS.

When it was found that no marked improvements could be made in balloons, the more advanced thinkers, turning their attention in an opposite direction, commenced to justly regard the winged being as the true model for flying machines; and experiments are now being made, in different parts of the world, of which all go to prove that "flight is far more a question of mechanical adaptation, construction and manipulation, than of enormous power," which, of course, in any experiment, must prove unavailable, if improperly applied. Some of the motive engines, lately exhibited in England, produced such remarkable power as certainly no bird possesses. One of four-horse power weighed 40 pounds, and occupied but a few cubic feet; another of 13 pounds exerted over one-horse power; and, at some experiments in France last year, a steam engine of two and a half horse power weighed 80 ℔s.; and, being applied to a machine with two vertical screw propellers of 12 ft. diameter each, it raised 120 ℔s. of the whole weight of 160 ℔s.

But, as far as known, these different motive powers have been employed so far only to elevate and propel machines by vertical fan-like contrivances—helicopterics or by æroplanes, pushed forward and upward by screw propellers; either quite as irrational as ballooning, because the rigid plane, wedged forward and upward at a given angle, in a straight line, or in a circle, does not embody the principles carried out in nature. Hence, the several advocates of the æroplane and helicopteric have met with but indifferent success.

Perhaps the best representative model of a flying machine on the principles of inclined planes, was that of Mr. Stringfellow, exhibited in London, in 1868, and which occasionally could rise. It had three æroplanes, superimposed as advocated by Wenham, the frames of which were made of light wood, with cloth drawn over it tightly, like rigid kites, fixed parallel one above the other, with a tail attached to the middle one. It had a small box underneath for the motive power, and a light screw propeller behind for pushing it forward. By giving the machine an upward angle, the planes strike continually upon new layers of air, and so cause a rise, like a kite pushed from behind. The whole structure had about thirty-six square feet of surface, and weighed, including the steam engine, which exerted nearly one-half horse power, under 12 pounds. It proved conclusively that, while the inclined plane, in a practical and different form, is necessary for ærostation, the secret of solving the problem lays far more in the mechanical application of certain laws governing the art of flight, than in enormous power.

These kite-form machines did not succeed, in spite of their great motive power and lightness, because the supporting planes were not active and flexible, but presented passive or dead surfaces, without power to accommodate themselves to altered circumstances. These planes were made to strike the air at a given angle, instead of continually changing to suit the elastic medium, and in which respect the ordinary kite is a better flying machine. If not driven with great velocity, such a machine can not support itself in the atmosphere; besides, on account of its great surface exposed, a strong wind can easily capsize it; while natural wings, on the contrary, present small flying surfaces, and their great speed converts the space through which they are driven, into a solid basis for support. This arrangement enables wings to seize and utilize the air, and renders them superior to the adverse currents, not of their forming. In this respect they entirely differ from balloons, and all forms of fixed æroplanes.

The different small helicopteric models, relying entirely on the aid of the screw, made from time to time, were also lacking, as stated before, in some of the true principles of flight; although some of these models could not only rise, but also carry a certain amount of freight, as was shown by the delicately constructed clockwork models of M. Nadar, a prominent French scientist, and others. One remarkable model, exhibited some years ago, was that of M. Phillips. It was made entirely of metal, weighed two pounds, had four two-bladed fans inclined to the horizon at an angle of twenty degrees, and made to revolve in opposite directions with immense energy. The motive power employed was obtained from the combustion of charcoal, nitre and gypsum, the products of combustion mixing with water in the boiler and forming gas-charged steam, which was delivered at a high pressure from the extremities of the arms of the fans, on the principle discovered by Hero, of Alexandria.

The production of flight by artificial wings is the most ancient method proposed, and will, undoubtedly, in a greatly modified form, and in combination with other contrivances, solve the problem; but to exactly imitate natural wings will be found as impossible as the production by the other different methods proposed so far.

Of the more recent attempts at the solution of the problem by means of artificial wings, worked by steam power, the perhaps most determined was that of Mr. Kauffman, of Glasgow. The machine had superimposed æroplanes, similar to those used by Stringfellow. The two wings were of great length, narrow, pointed towards the end, and were made to flap up and down somewhat like the wings of a bird. The model exhibited weighed, complete, 42 ℔s., but the dimensions for a large machine were to be: length, about 30 ft.; hight, 5 ft.; width, 6 ft.; length of each wing, 60 ft.; surface of each, 400 ft.; total weight of machine, 8000 ℔s.; nominal power, 120 horses; intended speed, 60 miles per hour; with water supply for five hours and oil as fuel for ten hours. Besides, a pendule, weighing 85 ℔s., and 40 ft. in length, was attached, which could, telescope-like, be drawn up when necessary. The model was made exactly, to show the inventor's theory, and to ascertain if the connection to the wings could be made strong enough to withstand the violent twisting and bending strains to which they were exposed. When steam at a pressure of over 150 ℔s. was turned on, the wings made a short series of furious flaps and broke. The experiment failed, because, to exactly imitate the movements of the long and delicate wings of fast-flying birds on a large scale, is impossible; the leverage to flap up and down 60 ft. long wings being simply enormous beyond computation, and no material can be found strong enough to withstand it.

Another machine, the propulsion of which was also to be effected by means of artificial wings, was exhibited some years ago in England. It differed entirely from the other in this respect, that it was very light, weighing scarcely 30 ℔s., and was intended for a man to fly by his own muscular power. It had about 70 square feet of surface, two short wings, and the ribs were made of paragon wire, such as is used in umbrellas, and covered with silk. By a preliminary quick run, the inventor could take short, jump-like flights of more than 100 feet; but this machine was also in a very crude state of perfection.

These different practical experiments, although more or less unsuccessful, and others similar, but of which many models were far more ingenious than practical, have at least established the certain prospect and certainty of an early solution of the problem. And were it not that but very few, comparatively, of the great number of theories, which have been proposed from time to time for the accomplishment of this great object, have been submitted to anything resembling even the remotest approach to practical tests, and that the lack of means is generally the insurmountable barrier in experimenting, ærial navigation would to-day be an established fact.