STEERING BY MEANS OF A GYROSCOPE.

A ship at sea has only to be steered in a horizontal direction; the water in which it is floated assures its stability in a vertical direction; but when a flying machine is once launched in the air, it has to be steered in two directions—that is, the vertical and the horizontal. Moreover, it is constantly encountering air currents that are moving with a much higher velocity than any water currents that have ever to be encountered. It is, therefore, evident that, as far as vertical steering is concerned, it should be automatic. Some have suggested shifting weights, flowing mercury, and swinging pendulums; but none of these is of the least value, on account of the swaying action which always has to be encountered. A pendulum could not be depended upon for working machinery on board a ship, and the same laws apply to an airship. We have but one means at our disposal, and that is the gyroscope. When a gyroscope is spun at a very high velocity on a vertical axis, with the point of support very much above the center of gyration, it has a tendency to maintain a vertical axis; a horizontal or swinging motion of its support will not cause it to swing like a pendulum. It therefore becomes possible by its use to maintain an airship on an even keel. In a steam steering apparatus, such as is used on shipboard, it is not sufficient to apply steam-power to move the rudders, unless some means are provided whereby the movement of the rudder closes off the steam, otherwise the rudder might continue to travel after the effect had been produced, and ultimately be broken; and so it is with steering a flying machine in a vertical direction. Whenever the fore and aft rudders respond to the action of the gyroscope and are set in motion, they must at once commence to shut off the power that works them, otherwise they would continue to travel. In the photograph ([Fig. 52]) I have shown an apparatus which I constructed at Baldwyn’s Park. It will be seen that the gyroscope is enclosed in a metal case; a tangent screw, just above the case, rotates a pointer around a small disc, which admits of the speed of the gyroscope being observed. Steam is admitted through a universal joint, descends through the shaft and escapes through a series of small openings placed at a tangent, so as to give rotation to the wheel after the manner of a Barker’s mill. The casing about the rotating wheel is extremely light as relates to the wheel, so that, when the gyroscope is once spun on a vertical axis, the rest of the apparatus may be tilted in any direction, while the gyroscope and its attachments maintain a vertical axis. The gyroscope and its attachments are suspended from a long steel tube, which in reality is a steam cylinder. The sleeve which supports the gyroscope moves freely in a longitudinal direction, and the whole is held in position by a triple-threaded screw on the small tube above the cylinder. The steam is admitted through a piston value operated by a species of link motion, as shown. The piston-rod extends to each end of the cylinder, and regulates the rudders by pulling a small wire rope, the travel of the piston being about 8 feet. At the end of the cylinder (not shown) the piston-rod is provided with an arm and a nut which engages the small top tube—this tube being provided with a long spiral—so that, as the piston moves, the top tube is rotated, and thereby slides the gyroscope’s support, and changes its position as relates to the piston valve. It will, therefore, be seen that the action is the same as with the common steam steering gear used on shipboard. A little adjusting screw at the right hand of the print is shown. The upward projecting arm of the bell crank lever is for the purpose of attaching the wooden handle, making it possible to move the connecting-rod instantly into a position where the steam piston will move the rudders into the position shown ([Fig. 56]).

I copy the following from a description which I wrote of this apparatus at the time:—

“Gyroscope Apparatus for Automatically Steering Machine in a Vertical Direction.

“This apparatus consists of a long steam cylinder which is provided with a piston, the piston-rod extending beyond the cylinder at each end; the ropes working the fore and aft rudders are attached to the ends of this piston-rod, and steam is supplied through an equilibrium valve. The gyroscope is contained in a gunmetal case, and is driven by a jet of steam entering through the trunnions. When the gyroscope is spinning at a high velocity, the casing holding it becomes very rigid and is not easily moved from its vertical position. If the machine rears or pitches, the cylinder and valve are moved with the machine while the gyroscope remains in a vertical position. This causes the steam valve to be moved so as to admit steam into the cylinder and move the piston in the proper direction to instantly bring the machine back into its normal position. As the fore and aft rudders are moved, the long tubular shaft immediately over the steam cylinder is rotated in such a manner as to move the whole gyroscope in the proper direction to close off the steam. The apparatus may be made to regulate at any angle by adjusting the screw which regulates the position of the tubular shaft. The link that suspends the end of the steam valve connecting-rod is supported by a bell crank lever, and while the machine is moving ahead, the lever occupies the position shown in the photograph ([Fig. 52]); but if the machinery and engine stop, the bell crank lever may be moved so as to throw the connecting-rod below the centre, when the steam will move the piston in the proper direction to throw both the rudders into the falling position, as shown in [Fig. 56].”

Fig. 52.—Gyroscope, used for the control of the fore and aft horizontal rudders, thus keeping the machine on an even keel while in the air.

Fig. 53.—In order to adjust the lifting effect so that it was directly over the centre of gravity, and to test the action of my fore and aft horizontal rudders, I ran the machine along the steel rail i, i, and adjusted my weights and aeroplanes in such a manner that, when the machine was run at a speed of 30 miles an hour along the track, with the rudders adjusted in the manner shown, the front wheel j, was raised from the steel track and the small wheel m, brought into contact with the upper track h. When the rudder b, b, is in this position, it produces a strong lifting effect, while the rudder c, c, does not lift at all.

[Fig. 53 enlarged] (66 kB)

Fig. 54.—This shows the rudders placed in such a position that b, b, does not lift at all, while c, is placed at such an angle as to produce a strong lifting effect, especially so as it is in the blast of the screws d, d. With the rudders in this position, and at a speed of 30 miles an hour, I was able to lift the rear wheels k, k, off the steel rails and to bring the small wheel l, in contact with the upper track h. These experiments showed that the machine could be tilted in either direction by changing the position of the rudder.

[Fig. 54 enlarged] (60 kb)

Fig. 55.—When the rudders were placed in the position shown, and the machine was run over the track at a rate of 40 miles an hour, all the weight was lifted off the wheels, j, and k, and both the small wheels m, and l, engaged the upper track.

[Fig. 55 enlarged] (62 kB)

Fig. 56.—In case of a breakdown or failure of the engines when the machine is in flight, it is necessary to place the rudders in the position shown, in order to prevent the machine from diving to the earth. When the rudders are in this position, a rapid and destructive descent is not possible, as the machine will preserve an even keel while falling.

[Fig. 56 enlarged] (50 kB)

CHAPTER VII.
THE SHAPE AND EFFICIENCY OF AEROPLANES.

In Prof. Langley’s lifetime, we had many discussions regarding the width and shape of aeroplanes. The Professor had made many experiments with very small and narrow planes, and was extremely anxious to obtain some data regarding the effect that would be produced by making the planes of greater width. He admitted that by putting some two or three aeroplanes tandem, and all at the same angle, the front aeroplane a ([Fig. 57]), would lift a great deal more than b, and that c, would lift still less. He suggested the arrangement shown at a′, b′, c′, in which b′ is set at such an angle as to give as much additional acceleration to the air as it had received in the first instance by passing under a′, and that c′, should also increase the acceleration to the same extent. With this arrangement, the lifting effect of the three aeroplanes ought to be the same, but I did not agree with this theory. It seemed to me that it would only be true if it dealt with the volume of air represented between j, and k, and that he did not take into consideration the mass of air between k, and l, that had to be dealt with, and which would certainly have some effect in buoying up the stream of air, j, k. Prof. Langley admitted the truth of this, and said that nothing but experiment would demonstrate what the real facts were. But it was a matter which I had to deal with. I did not like the arrangement a′, b′, c′, as the angle was so sharp, especially at c′, that a very large screw thrust would be necessary. I therefore made a compromise on this system which is shown at a′′, b′′, c′′. In this case a′′, has an inclination of 1 in 10, b′′ an inclination of 1 in 6, and c′′ an inclination of 1 in 5. It will be seen that this form, which is shown as one aeroplane at a′′′, b′′′, c′′′, is a very good shape. It is laid out by first drawing the line c, d, dropping the perpendicular equal to one-tenth of the distance between c and d, and then drawing a straight line from c, through e, to f, where another perpendicular is dropped, and half the distance between d and e laid off, and another straight line drawn from e, through g, to h, and the perpendicular h, i, laid off the same as f, g. We then have four points, and by drawing a curve through these, we obtain the shape of the aeroplane shown above, which is an exceedingly good one. This shape, however, is only suitable for velocities, up to 40 miles per hour; at higher velocities, the curvature would be correspondingly reduced.

Fig. 57.—Diagram showing the evolution of a wide aeroplane.