ARTIFICIAL AND NATURAL FLIGHT.

ARTIFICIAL AND
NATURAL FLIGHT.

BY
SIR HIRAM S. MAXIM.

WITH 95 ILLUSTRATIONS.

WHITTAKER & CO.,
2 WHITE HART STREET, PATERNOSTER SQUARE,
LONDON, E.C.,
AND 64-66 FIFTH AVENUE, NEW YORK.
1908.

PREFACE.

It was in 1856 that I first had my attention called to the subject of flying machines. My father, who was a profound thinker and a clever mechanician, seems to have given the subject a great deal of thought, and to have matured a plan identical with what has been proposed by hundreds since that time. I was then sixteen years of age, and a fairly good mechanician, and any new thing in the mechanical line interested me immensely.

My father’s proposed machine, of which he made a sketch, was of the Hélicoptère type, having two screws both on the same axis—the lower one to be right hand and mounted on a tubular shaft, and the top one to be left hand and mounted on a solid shaft running through the lower tubular shaft. These screws were to be rotated in reverse directions by means of a small pinion engaging a bevel gear attached to each of the shafts. His plan contemplated large screws with very fine pitch, and he proposed to obtain horizontal motion by inclining the axis forward. He admitted that there was no motor in existence light enough, but thought one might be invented, and that an engine might be worked by a series of explosions in the cylinder, that is, what is known to-day as internal combustion; but he was not clear how such an engine could be produced. He, however, said that a flying machine would be so valuable in time of war, that it mattered little how expensive the explosive might be, even if fulminate of mercury had to be used. It is interesting to note in this connection that the great Peter Cooper of New York thought out an identical machine about the same time, and actually commenced experiments. It seems that this gentleman regarded fulminate of mercury as altogether too feeble and inert, because we find that he selected chloride of nitrogen as his explosive agent. However, his work was soon brought to an end by the loss of the sight of one eye, after which time he had no further dealings with this lively explosive.

The many early conversations that I had with my father on the subject kept the matter constantly before me, and I think it was in 1872, after having seen Roper’s hot-air engine and Brayton’s petroleum engine, that I took the matter up, and commenced to make drawings of a machine of the Hélicoptère type, but instead of having one screw above the other, I saw at once that it would be much better if the two screws were widely separated, so that each would engage new air, the inertia of which had not been disturbed. The designing of the machine itself was a simple matter, but the engine gave me trouble. No matter from what point I examined the subject, the engine was always too heavy. It appears that the Brayton engine was shown at the Centennial Exhibition at Philadelphia in 1876, and that Otto visited this exhibition. Up to that time, he had been making a species of rocket engine—that is, an engine in which an explosive mixture shot the piston upward and then sucked it back, a rack and pinion transmitting movement to the rotating shaft by means of a pawl and ratchet. He appears to have been much interested in the Brayton engine, as it was evidently very much in advance of his own. It actually developed, even at that time, one horse-power per hour for every pound of crude petroleum consumed, but it was very heavy indeed, very difficult to start, and not always reliable. The shaft that worked the valve gear was parallel to the cylinder, and placed in the exact position occupied by a similar shaft in the present Otto engine, but instead of revolving only half as fast as the crank shaft, it made the same number of revolutions. On Otto’s return to Germany, he evidently profited by what he had seen, and made a new engine, which in reality was a cross between his own and the Brayton; the result was a very important invention, which has been of incalculable value to mankind. It is this engine which is now propelling our motor cars, and it is the only engine suitable for employment on a flying machine; but even this motor was not in a sufficiently high state of development as far as lightness was concerned, to be of any use to me. The drawings which I made in 1873, although of little or no value, kept my thoughts on artificial flight, and while I was away from home attending to business, especially when in foreign countries, I often amused myself by making mathematical calculations. Quite true, the formula which I used at the time—Haswell’s—was not correct; still, it was near enough to the mark to be of considerable value. Moreover, the error in this formula affected the Hélicoptère quite as much as the aeroplane system, and as I was working with the view of ascertaining the relative merits of the two systems, the error, although considerable, did not have any influence at all in the decision which I arrived at—namely, that the aeroplane system was the best. The machine that I thought out at that time contemplated superposed aeroplanes of very great length from port to starboard. The size in the other direction was more for the purpose of preventing a rapid fall than for a lifting effect. I saw that it would be necessary to have horizontal fore and aft rudders placed a long distance apart, so as to prevent rapid pitching, and it appeared to me that the further these rudders were apart, the easier it would be to manœuvre the machine. As I never had any doubts regarding the efficiency of screw propellers working in the air, I decided to use two of these of a large size rotating in opposite directions. Of course, all this speculation was theory only, but I verified it later on by actual experiments before I built my machine, and it is very gratifying to me to know that all the successful flying machines of to-day are built on the lines which I had thought out at that time, and found to be the best. All have superposed aeroplanes of great length from port to starboard, all have fore and aft horizontal rudders, and all are driven with screw propellers.