Photo E. Levick, N. Y.
The creation of Henson’s flying machine at that early period is one of the most original and fruitful achievements in the century-long development of the modern aëroplane. Barring the torsional wing-tips invented more recently, it hardly differs in principle from the successful monoplane of to-day. The same mode of propulsion, the same mode of sustention, the same mode of launching and lighting, the same mode of steering and control. What has been added since is not so much original invention as perfection of detail through the combined efforts of many designers. After Cayley, Henson, as nearly as any one person was the inventor of the flying machine. He did not bring his conception to practical maturity, nor was that to be expected; but he did lay down the broad lines which have led others to success. His ideas still feature every practical aëroplane, and particularly every successful monoplane. Indeed, it is now possible to construct an aëroplane from Henson’s description that will fly, even in breezy weather, with a stability practically as good as that of the early Voisin and Antoinette machines before the use of the aileron or torsional wing was practiced. It is all a question of wise proportioning and sufficient motive power.
So much for Henson’s contrivance as an abstract invention. The concrete, full scale machine was to spread 6,000 square feet of surface, weigh 3,000 pounds, and be propelled by a high pressure steam engine of 25 or 30 horse power. The machine was not completed on a large scale, and wisely so; for it was inadequately powered, and, moreover, required many refinements of detail to make it entirely practical. These improvements had to be left to succeeding inventors with accumulated experience and resources.
In 1844 Mr. Henson began the construction of a steam-driven model, in partnership with his friend, Mr. Stringfellow, who designed the motor for it. They experimented together for some weeks with only meager success, but gaining valuable experience. A model of the Henson-Stringfellow machine is on exhibition at the South Kensington Museum.
In 1846 Stringfellow built a steam model aëroplane about the size of a large soaring bird, and weighing all together, with fuel and water, 6½ pounds. A special feature of this model was that its main surfaces were sloped like the wings of a bird, slightly concave below and feathered toward the back; thus making it more efficient and stable in flight. With a good head of steam, and propellers whirling, the model ran down a stretched wire, leaped into the air “and darted off in as fair a flight as it was possible to make, to a distance of about 40 yards.” Thus the first power-driven aëroplane to fly successfully was the little steam model constructed by Stringfellow in 1846.
Fig. 31.—Wenham’s Aëroplane, 1866.
In 1866, two decades after the flight of Stringfellow’s monoplane, Mr. F. H. Wenham, another Englishman illustrious in the annals of aëronautics, patented the multiplane; that is, an aëroplane comprising two or more superposed surfaces. This proved to be a valuable contribution to the art of aviation, and continues in use at the present time. The device furnished an increase of sustaining surface without enlargement of the ground plan. It moreover lends itself conveniently to a strong and simple trussing of the surfaces. Some designers protest that superposed surfaces blanket one another; but the advantages just named seem amply to compensate for this objectionable feature. If the surfaces be properly spaced, very little interference is found; moreover, any blanketing that may occur diminishes the drift as well as the lift,[20] though not necessarily in the same proportion.
Wenham’s aëroplane is illustrated in Fig. 31. The rider lies underneath the multiple wings, so as to diminish the resistance to progression through the air. The apparatus could thus be used as an aërial toboggan for coasting down the atmosphere. To prolong the flights two flappers actuated by a treadle were to be employed, their ends being hinged at a point above the operator’s back. Though the device was patented, no very serious efforts were made to operate it practically. Once, indeed, the inventor took his glider to a meadow and mounted it, during a lull in the evening wind, but soon a gust caught him up, carried him some distance from the ground and toppled him over sidewise, breaking some of the surfaces. The machine disclosed some good working principles; but it was inadequately ruddered, and too feebly constructed, to weather the buffets of the prevailing ground currents.