INVENTIONS TO ATTACK AERIAL CRAFT.—Before any nation had the opportunity to make an actual test on the battlefield, inventors were at work to devise a means whereby an aerial foe could be met. In a measure the aerial gun has been successful, but months of war has shown that the aeroplane is one of the strongest arms of the service in actual warfare.
It was assumed prior to the European war that the chief function of the aeroplane would be the dropping of bombs,—that is for service in attacking a foe. Actual practice has not justified this theory. In some places the appearance of the aeroplane has caused terror, but it has been found the great value is its scouting advantages.
FUNCTION OF THE AEROPLANE IN WAR.—While bomb throwing may in the future be perfected, it is not at all an easy problem for an aviator to do work which is commensurate with the risk involved. The range is generally too great; the necessity of swift movement in the machine too speedy to assure accuracy, and to attack a foe at haphazard points can never be effectual. Even the slowly-moving gas fields, like the Zeppelin, cannot deliver bombs with any degree of precision or accuracy.
BOMB-THROWING TESTS.—It is interesting, however, to understand how an aviator knows where or when to drop the bomb from a swiftly-moving machine. Several things must be taken into consideration, such as the height of the machine from the earth; its speed, and the parabolic curve that the bomb will take on its flight to the earth.
When an object is released from a moving machine it will follow the machine from which it is dropped, gradually receding from it, as it descends, so that the machine is actually beyond the place where the bomb strikes the earth, due to the retarding motion of the atmosphere against the missile.
The diagram Fig. 90 will aid the boy in grasping the situation. A is the airship; B the path of its flight; a the course of the bomb after it leaves the airship; and D the earth. The question is how to determine the proper movement when to release the bomb.
METHOD FOR DETERMINING MOVEMENT OF A BOMB.—Lieut. Scott, U. S. A., of the Coast Survey Artillery, suggested a method for determining these questions. It was necessary to ascertain, first, the altitude and speed. While the barometer is used to determine altitudes, it is obvious that speed is a matter much more difficult to ascertain, owing to the wind movements, which in all cases make it difficult for a flier to determine, even with instruments which have been devised for the purpose.
Fig. 90. Course of a Bomb.
Instead, therefore, of relying on the barometer, the ship is equipped with a telescope which may be instantly set at an angle of 45 degrees, or vertically.
Thus, Fig 91 shows a ship A, on which is mounted a telescope B, at an angle of 45 degrees. The observer first notes the object along the line of 45 degrees, and starts the time of this observation by a stop watch.