A modified and peculiar form and style of wings, as mentioned here before, must also be employed in combination with the planes and fans, to serve the double purpose of driving and lifting. By the manipulation of these wings the accumulating and compressed air is thrown underneath the machine, thereby urging the same in a forward and upward direction, and by which the planes in front are made to continually rise upon new layers of the elastic medium, like a kite when the boy runs forward.
The planes must be fixed in such a manner that they can be set at different angles with the horizon, in order that the machine may rise sooner when the angle is greatest, because of the greater resistance of the air against a larger surface exposed; and to glide through the atmosphere swifter, after elevation has been attained, when the angle of the planes is most acute, thereby offering the least amount of surface to the horizontally opposing air. No flying creature rises in the air vertically, but ascends at an incline.
A swallow, one of the very best flyers, lifts itself with difficulty from the ground. An eagle, particularly after eating, has to run some distance flapping its wings vigorously before it can rise. An insect, possessing considerable spring-power in its limbs, always takes a good jump at the moment its wings are spread out for elevation, at an upward angle forward. With similar contrivances for the purpose must a practical flying machine be provided. It should, in combination with a certain amount of spring power, to enable it to rise with greater ease at the final moment, and also to reduce the shock in alighting to a minimum, have wheels to run over the ground, until sufficient force and momentum has been attained to launch it into the boundless realms of space.
To be thoroughly practical, the machine must be under perfect control, and be made to descend upon any spot desired with absolute safety and ease. This can be accomplished by the combined effort of the propellors and wings. By exerting the power of these contrivances in opposite directions the disturbed atmosphere is thrown in volumes underneath the machine, which, on account of its similarity to a parachute, although of a greatly different form, can be made to descend vertically and very slow.
The doubt expressed by many, that the guidance of an air ship is possible, is easily refuted. All bodies, possessing the propelling force within them, can guide themselves in an elastic medium. Of this we have millions of examples before us in all flying creatures.
Finally, a practical shape and proper size and weight will form one of the most essential elements in a successful flying machine, and which has been disregarded more or less so far. Of course, it is impossible to calculate already, before an actual machine has been built and datas can be fixed, the limits of these factors in the average ærial structure. My impressions are, that the weight of a single carriage will be from 400 to 500 lbs., inclusive; a motive force of 3 to 5 horse power. It will have a total length of from forty to fifty feet, by about the same in width, from tip to tip; and a surface of from 500 to 600 square feet will be more than sufficient to sustain a total weight of 1000 lbs.; for such a machine will be capable to carry from three to four persons, or its equivalent weight of express matter, letters, newspapers, and other light freight. Of course, free mail facilities for our wise solons will, perhaps, unfortunately have to be barred out.
When the novelty and excitement of this style of travel will have subsided, we may take the next step in ærostation by carrying a much greater number of passengers and heavier freight; not in a single machine, but by making two or more to support inclined planes of certain construction between them. These planes, in swift horizontal flight, could be made to carry, in suitable cars underneath, much more than their own weight, because the power of support which the air affords to inclined planes at a great speed is simply enormous, amounting to 50 ℔s. per square ft. in a pressure of 100 miles per hour. For this purpose, the manner of placing these æroplanes one above the other, as proposed by Mr. Wenham many years ago, would be practical to some extent.
The great swiftness with which these machines are expected to travel, seems at first to rouse fear in us to trust our more or less valuable lives into such a wonderful structure; and it possibly staggers our belief that such great speed can be performed with any degree of safety to brittle bone and breathing valve. But all these objections are easily refuted. The ærial traveler sits securely inside the strong machine, in no danger of catching a cold from the strong air-current rushing by, very much like the passenger in a railroad car; and if of an inquisitive turn of mind for the beauty of the surrounding panorama, he has suitable windows for observation. If the air passenger suffers from gout, rheumatism, or is susceptible to sea-sickness, he will experience no inconvenience, because there is no jogging, no rumbling over cobble-stones or broken rails, or riding on a heavy sea; he will feel no motion at whatever hight he may be, but will glide voluptuously—without perception almost—like a summer cloud through the vast ocean of the ærial fluid.
The machine being under perfect control, can be made to travel very slow when towards the point of destination, and may be stopped at any hight to remain stationary or leisurely descend. And lastly, speed appears greatly diminished when the object is viewed from a distance, as we can observe on a railroad train. A telegraph pole standing near the track will flit by like a flash of lightning, so to speak; but if any considerable distance off, it disappears very slow. But when an object is followed by the eye from a considerable elevation, this fact is still more striking. The eye can command at a glance almost hundreds of miles of country, and a city can be seen at a distance of at least fifty miles in advance, giving the æronaut ample time for preparing a descent, if so desired. Of course, he must be well acquainted with landmarks, to know what part of country he is in; but this knowledge will be acquired much easier than water navigation.
Such about will be the coming flying-machine of the near future. The natural elements, so far from presenting barriers and obstacles, as they do to a great extent on land and ocean navigation, seem to be peculiarly inviting to ærostation.