of greater carrying capacity than the present standard; the modern 21-in. torpedo, for example, weighs approximately 1 ton, and would require a machine of about 4 tons gross lifting power. The older model, the 18-in. weapon, weighs about 12 cwt., and would require a machine with a gross lifting-power of 2½ tons, the latter being not very much in excess of the largest machines already in service.
§ 73. Aeroplane as affected by Discharge of Torpedo. It might be thought, considering the matter superficially, that the dropping of one-quarter of the gross weight of a machine whilst in flight would be a dangerous and risky business. But closer investigation shows that this is not the case; the resulting disturbance is one which can be quite easily rectified by the pilot. In the case of the modern machine, whose flight path is stable (the dynamically-stable machine), and which is said to be—and undoubtedly is—capable of flying itself, the disturbance calculated as due to the release of the torpedo is well within the permissible limit. The only condition to be observed is that the centre of gravity of the machine shall not be thrown forward or backward by the discharge; in other words, the centre of gravity of the torpedo, as carried, must be approximately in the same vertical line as that of the machine. If this condition is complied with, the resulting disturbance, assuming the torpedo as constituting one-quarter of the gross weight, is shown by the diagram Fig. 15. The torpedo being dropped at point p1, the path of flight p1 p2 becomes undulatory, the undulations dying out, as indicated in the figure, at a rate depending upon the degree of dynamic stability provided. The extent of the initial undulation is correctly represented to scale in the figure, and is the same as would be produced in a 70-mile-an-hour machine by an adverse wind gust of 10 miles per hour, a thing of everyday
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