The Curtiss Aviation Book

by Glenn Hammond Curtiss; Augustus Post

But we are not progressing. Can aeroplanes be used to kill the other fellow? Well, assuming him to be located as we have assumed him to be, there are several other questions which must be answered before we can clinch the main issue. Can a man act as aviator and at the same time manipulate the mechanism that may be found necessary to the killing of the other fellow? If not, can an aeroplane be built that will carry at least two men, one as aviator and the other as manipulator of the death-dealing apparatus, and, at the same time, carry enough extra weight, i. e., fuel, to keep aloft long enough to accomplish the necessary flight and also carry the projectiles and dropping device? Yes. The two passengers may be estimated to weigh three hundred pounds. The dropping device may be estimated to weigh not to exceed fifty pounds. At least three known types of aeroplane carry six hundred and fifty pounds of weight for a continuous flight of two hundred miles in length. That leaves two hundred and fifty pounds that can be devoted to the carrying of projectiles.

So far the coast seems clear, but a small storm appears in the offing; can this two hundred and fifty pounds, or any considerable part of it, be dropped from a moving aeroplane without disturbing its equilibrium to such an extent as to render the machine unmanageable? Any weight can be dropped from the centre of lift without disturbing the equilibrium. Thirty-eight pounds have been dropped from one machine from a point three feet in front of the centre of lift without disturbing the equilibrium.

Admitting that the necessary weight can be carried and can be dropped, we next encounter the highly important question, what can we hit from a height of, say, three thousand five hundred feet? At this point the problem becomes one of pure fire control, and is directly analogous to target practice in our sea-coast defences. Since the aeroplane is moving forward at a definite rate of speed at the instant of dropping the projectile, it follows that there is an initial velocity given to the projectile. This velocity is dependent upon the forward speed of the machine and varies with it. Gravity exerts an influence on the drop of the projectile, which influence increases the speed of drop as the altitude from which the shell is dropped increases. The direction and force of the wind currents through which the projectile must fall are variable and they all exert influences tending to cause the projectile to swerve from its original course to a degree dependent upon their strength and the thickness of each stratum of air. The size of the target and, if it be animals or men, the direction and rate of movement of the target, are all factors to a successful hit.

Practice has shown us that the principal factors are the forward speed of the machine and the altitude. The variations due to wind currents through which the projectile must pass in falling are negligible. The only targets to be chosen will be sufficiently large and immobile to warrant an assumption that they can be hit. Aerial target practice will never degenerate to the sniping of individuals. It will be directed against ships, small boats, armies, cavalry, quartermaster and field artillery trains and similar large bodies of men or animals, or against the strategical and tactical points alluded to above.

The problem then simmers itself down to a more or less accurate solution of a method for determining the forward speed of the machine and its altitude, which, with a suitable set of tables and suitable mechanical devices for releasing the projectile at the proper instant, will produce a reasonably good target practice.

For some time the solution of the forward speed of an aeroplane seemed impracticable. It has now been solved by the simple use of a telescope, mounted on a gimbal so as to maintain its horizontal position and movable vertically along a graduated arc. By setting the telescope to read an angle of forty-five degrees and snapping a stop watch on an object which lies in the line of sight of the telescope produced, and then swinging the telescope so as to point vertically downward, we can, by snapping the stop watch a second time as the sighting point again comes into the field of vision, ascertain the exact time it has taken the machine to cover the distance measured by forty-five degrees of arc. Our altitude is known by reading a barometer. We then have two known angles of a right triangle and one known side, viz., the altitude. By a set of tables, already made out, we can determine our forward speed.

Now, all of this is done as a preliminary to actually dropping the projectile. After we have the forward speed and the altitude we simply consult another set of previously prepared tables and read from those tables an angle. This angle shows the proper point of drop to hit another point on the ground somewhere in advance of the aeroplane. After picking the angle out of the table we set our telescope to read the known angle and, when the line of sight, produced, is on the objective, we release or "trip" the projectile. This has actually been done. Now I ask you the question, can an aeroplane be used to kill the other fellow?

Can an aeroplane be used to prevent the other fellow from killing us? Of course it is much superior to Santa Ana's mule for purposes of rapid departure from the scene of hostilities, but that is hardly the test we apply. It is, on the other hand, inferior as a shield to the ordinary breastworks constructed by armies in the field, but, again, that is not precisely the test to be applied.

The most effective way in which we can keep the other fellow from killing us is to find out where he is, what he is doing and how he proposes to accomplish his–to us reprehensible, to him laudable–object. Accordingly we apply the information test to the aeroplane. Can we use it to gather information of the enemy, his lines of communication, his lines of defences, his probable lines of advance or retreat, his rail and water communications, his artillery positions and gun emplacements, and a host of other things, all of which tend to produce success or failure in battle? In other words, can we use the aeroplane to prevent the enemy from killing us?

In order to make use of information there are two distinct steps which must be taken: First, it must be gathered; second, it must be communicated to the proper officers for transmission to the Commanding General in the field. No information is of value until it is communicated to an officer competent to act upon it.