Fig. 35.—Hargrave’s Kite.
A very novel and interesting type of aëroplane model was tested by Mr. Horatio Phillips in 1893. After careful preliminary experiments with various forms of curved “sustainers,” or lifting surfaces, tested in a wind tunnel, to determine which were most suitable wing forms, he finally constructed the flying apparatus shown in [Plate XIV]. This consisted of a compound aëroplane composed of many superposed narrow curved slats, the whole resembling an open Venetian blind. These curved blades, or sustainers, measured 12 feet long, 1.5 inches wide, 2 inches apart, and were held in a frame sharpened to cleave the air with slight resistance. The entire aëroplane spread 136 square feet of lifting surface, and was mounted on a truck as shown, carrying a steam engine and boiler, to actuate a two blade propeller 6 feet in diameter. The whole apparatus weighed 330 pounds, to which a dead load was usually added, and ran around a circular wooden track 628 feet in circumference, being tethered at the center, as in Tatin’s experiment. The apparatus readily lifted itself, when running at a speed of 28 miles an hour, and carried at the rate of 72 pounds per horse power, the added load weighing at times nearly one fourth that of the machine itself. The ultimate purpose of the experiment was to prepare the way for a one-man aëroplane like that shown in the lower part of the figure. This latter model actually carried a man across a field in 1904, but was found defective in longitudinal balance, because perhaps of its inadequate horizontal rudder. Apparently Mr. Phillips had in 1904 a machine capable of well-balanced flight, if he had made the rudders large enough, and provided a mechanism for rotating the slats at either wing end, so as to control the lateral poise, as proposed by the present writer in 1893, for practically that same flier (see [page 229]).
Phillips’s aëroplane shows a distinct advance over its predecessors, even Wenham’s multiplane, because of the careful curving of the sustainers. Tatin’s flat wing machine had, indeed, shown a greater efficiency as a whole, but that was likely due to less proportionate body resistance. To Phillips we owe the introduction of superposed arched surfaces, now so commonly used in mechanical flight. Whether he was wise in using so many narrow wings, instead of a few broad ones, was a question to be answered by precise measurement.
Prof. S. P. Langley, like Mr. Hargrave, made numerous flying models, trying, in turn, the power of twisted rubber, compressed air and steam. He constructed scores of gauzy winged contrivances which flitted about like huge butterflies or birds, till their mission was accomplished—that of illustrating a scientific principle to his inquiring mind. One by one they came into existence, enjoyed an ephemeral life, and then were consigned to the aëronautical attic of the Smithsonian Institution, a storehouse of quaint flying creatures. It was a most interesting collection which well merited preservation as the “juvenile” creations of an illustrious man. But the first experiments of Langley, like the similar ones of Hargrave, were of value chiefly as training to the inventor himself; they were not important advances in the art of aviation. Such advances were to follow the long preliminary training.
PLATE XIV.
PHILLIPS’ TETHERED AËROPLANE.
