Aircraft and Submarines

It was all very daring and chivalric, but it was not war according to twentieth century standards and was not long continued.

When at first the aviators of one side flew over the enemy's territory diligently mapping out his trenches, observing the movements of his troops, or indicating, by dropping bunches of tinsel for the sun to shine upon or breaking smoke bombs, the position of his hidden battery, the foe thus menaced sought to drive them away with anti-aircraft guns. These proved to be ineffective and it may be said here that throughout the war the swift airplanes proved themselves more than a match for the best anti-aircraft artillery that had been devised. They could complete their reconnaissances or give their signals at a height out of range of these guns, or at least so great that the chances of their being hit were but slight. It was amazing the manner in which an airplane could navigate a stretch of air full of bursting shrapnel and yet escape serious injury. The mere puncture, even the repeated puncture, of the wings did no damage. Only lucky shots that might pierce the fuel tank, hit the engine, touch an aileron or an important stay or strut, could affect the machine, while in due course of time a light armour on the bottom of the fusillage or body of the machine in which the pilot sat, protected the operator to some degree. Other considerations, however, finally led to the rejection of armour.

Accordingly it soon became the custom of the commanders who saw their works being spied out by an enemy soaring above to send up one or more aircraft to challenge the invader and drive him away. This led to the second step in the development in aërial strategy. It was perfectly evident that a man could not observe critically a position and draw maps of it, or seek out the hiding place of massed batteries and indicate them to his own artillerists, and at the same time protect himself from assaults. Accordingly the flying corps of every army gradually became differentiated into observation machines and fighting machines – or avions de réglage, avions de bombardement, and avions de chasse, as the French call them. In their order these titles were applied to heavy slow-moving machines used for taking photographs and directing artillery fire, more heavily armed machines of greater weight used in raids and bombing attacks, and the swift fighting machines, quick to rise high, and swift to manœuvre which would protect the former from the enemy, or drive away the enemy's observation machines as the case might be. In the form which the belligerents finally adopted as most advantageous the fighting airplanes were mainly biplanes equipped with powerful motors seldom of less than 140 horse-power, and carrying often but one man who is not merely the pilot, but the operator of the machine gun with which each was equipped. Still planes carrying two men, and even three of whom one was the pilot, the other two the operators of the machine guns were widely adopted. They had indeed their disadvantages. They were slower to rise and clumsier in the turns. The added weight of the two gunmen cut down the amount of fuel that could be carried and limited the radius of action. But one curious disadvantage which would not at first suggest itself to the lay mind was the fact that the roar of the propeller was so great that no possible communication could pass between the pilot and the gunner. Their co-operation must be entirely instinctive or there could be no unity of action – and in practice it was found that there was little indeed. The smaller machine, carrying but one man, was quicker in the get-away and could rise higher in less time – a most vital consideration, for in the tactics of aërial warfare it is as desirable to get above your enemy as in the days of the old line of battleships it was advantageous to secure a position off the stern of your enemy so that you might rake him fore and aft.

The machines ultimately found to best meet the needs of aërial fighting were for the Germans always the Fokker, and the Taube – so called from its resemblance to a flying dove, though it was far from being the dove of peace. The wings are shaped like those of a bird and the tail adds to the resemblance. The Allies after testing the Taube design contemptuously rejected it, and indeed the Germans themselves substituted the Fokker for it in the war's later days.

The English used the "Vickers Scout," built of aluminum and steel and until late in the war usually designed to carry two aviators. This machine unlike most of the others has the propeller at the stern, called a "pusher" in contradistinction to the "tractor," acting as the screw of a ship and avoiding the interference with the rifle fire which the pulling, or tractor propeller mounted before the pilot to a certain degree presents. The Vickers machine is lightly armoured. The English also use what was known as the "D. H. 5," a machine carrying a motor of very high horse-power, while the Sopwith and Bristol biplane were popular as fighting craft.

The French pinned their faith mainly to the Farman, the Caudron, the Voisin, and the Moraine-Saulnier machines. The Bleriot and the Nieuport, which were for some reason ruled out at the beginning of the war, were afterwards re-adopted and employed in great numbers.

It would be gratifying to an American author to be able to describe, or at least to mention, the favourite machine of the American aviators who flocked to France immediately upon the declaration of war, but the mortifying fact is that having no airplanes of our own, our gallant volunteer soldiers of the air had to be equipped throughout by the French with machines of their favourite types. After we entered the war we adopted a 'plane of American design to which was given the name "Liberty plane."

It may be worth while to revert for a moment to the distinction drawn in a preceding paragraph between the pusher propeller and the tractor which revolved in front of the aviator and of his machine gun. It would seem almost incredible that two heavy blades of hard wood revolving at a speed not less that twelve hundred times a minute, a speed so rapid that their passage in front of the eyes of the aviator interfered in no way with his vision, should not have blocked a stream of bullets falling from a gun at the rate of more than six hundred a minute. Nevertheless it was claimed during the earlier days of the war that these bullets were not appreciably diverted by the whirling propellers nor were the latter apparently injured by the missiles. The latter assertion, however, must have been to some extent disproved because it came about that the propellers of the later machines were rimmed with a thin coating of steel lest the blades be cut by the bullets. But the amazing ability of modern science to cope with what seemed to be an insoluble problem was demonstrated by the invention of a device light and compact enough to be carried in an airplane, which applied to the machine gun and timed in accordance with the revolutions of the propeller so synchronized the shots with those revolutions that the stream of lead passed between the whirling blades never once striking. The machine was entirely automatic, requiring no attention on the part of the operator after the gun was once started on its discharge. This device was originally used by the Germans who applied it to their Fokker machines. It was claimed for it that by doing away with the wastage caused by the diversion of the course of bullets, which struck the revolving propellers, it actually saved for effective use about thirty per cent. of the ammunition employed. As the amount of ammunition which can be carried by an airplane is rigidly limited this gave to the appliance a positive value.

Reference has been made to the extraordinary immunity of flying airplanes to the attacks of anti-aircraft guns. The number of wounds they could sustain without being brought to earth was amazing. Grahame-White tells of a comparison made in one of the airdromes of the wounds sustained by the machines after a day's hard scouting and fighting. One was found to have been hit no less than thirty-seven times. Curiously enough the man who navigated it escaped unscathed. Wounds in the wings are harmless. But the puncture of the fuel tank almost certainly means an explosion and the death of the aviator in the flame thousands of feet in the air. During an air battle before Arras, a British aviator encountered this fate. When his tank was struck and the fusillage, or body, of his machine burst into flames, he knew that he was lost. By no possibility could he reach the ground before he should be burned to death. A neighbouring aviator flying not far from him told the story afterwards:

Jack was not in the thick of this fight [said he]. He was rather on the outskirts striving to get in when I suddenly saw his whole machine enveloped in a sheet of flame. Instantly he turned towards the nearest German and made at him with the obvious intention of running him down and carrying him to earth in the same cloud of fire. The man thus threatened, twisted and turned in a vain effort to escape the red terror bearing down upon him. But suffering acutely as he must have been, Jack followed his every move until the two machines crashed, and whirling over and over each other like two birds in an aërial combat fell to earth and to destruction. They landed inside the German lines so we heard no more about them. But we could see the smoke from the burning débris for some time.

As the range of anti-aircraft guns increased the flyers were driven higher and higher into the air to escape their missiles. At one time 4500 feet was looked upon as a reasonably safe height, but when the war had been under way about two years the weapons designed to combat aircraft were so improved that they could send their shots effectively 10,000 feet into the air. If the aircraft had been forced to operate at that height their usefulness would have been largely destroyed, for it is obvious that for observation purposes the atmospheric haze at such a height would obscure the view and make accurate mapping of the enemy's position impossible. For offensive purposes too the airplanes at so great an elevation would be heavily handicapped, if not indeed rendered impotent. As we shall see later, dropping a bomb from a swiftly moving airplane upon a target is no easy task. It never falls direct but partakes of the motion of the plane. It is estimated that for every thousand feet of elevation a bomb will advance four hundred feet in the direction that the aircraft is moving, provided its speed is not in excess of sixty miles an hour. As a result marksmanship at a height of more than five thousand feet is practically impossible.

In the main this situation is met, as all situations in war in which efficiency can only be attained at the expense of great personal danger are met, namely, by braving the danger. When the aviators have an attack in contemplation they fly low and snap their fingers at the puff balls of death as the shrapnel from their appearance when bursting may well be called. Naturally, efforts were made early in the war to lessen the danger by armouring the body of the machine sufficiently to protect the aviator and his engine – for if the aviator escaped a shot which found the engine, his plight would be almost as bad as if the missile had struck him.

The main difficulty with armouring the machines grew out of the added weight. The more efficient the armour, the less fuel could be carried and the less ammunition. If too heavily loaded the speed of the machine would be reduced and its ability to climb rapidly upon which the safety of the aviator usually depends, either in reconnaissance or fighting, would be seriously impeded. The first essays in protective armour took the form of the installation of a thin sheet of steel along the bottom of the body of the craft. This turned aside missiles from below provided the plane were not so near the ground as to receive them at the moment of their highest velocity. But it was only an unsatisfactory makeshift. At the higher altitudes it was unnecessary and in conflict with other airplanes it proved worthless, because in a battle in the air the shots of the enemy are more likely to come from above or at least from levels in the same plane. The armoured airplane was quickly found to have less chance of mounting above its enemy, because of the weight it carried, and before long the principle of protecting an airplane as a battleship is protected was abandoned, except in the case of the heavier machines intended to operate as scouts or guides to artillery, holding their flights near the earth and protected from attack from above by their attendant fleet of swift fighting machines. Of these the Vickers machine used mainly by the British is a common type. It is built throughout of steel and aluminum, and the entire fusillage is clothed with steel plating which assures protection to the two occupants from either upward or lateral fire. The sides of the body are carried up so that only the heads of the aviators are visible. But to accomplish this measure of protection for the pilot and the gunner who operates the machine gun from a seat forward of the pilot, the weight of the craft is so greatly increased that it is but little esteemed for any save the most sluggish manœuvre.

Indeed just as aircraft, as a factor in war, have come to be more like the cavalry in the army, or the destroyers and scout cruisers in the navy, so the tendency has been to discard everything in their design that might by any possibility interfere with their speed and their ability to turn and twist, and change direction and elevation with the utmost celerity under the most difficult of conditions. It is possible that should this war run into the indefinite future we may see aircraft built on ponderous lines and heavily armoured, and performing in the air some of the functions that the British "tanks" have discharged on the battlefields. But at the end of three years of war, and at the moment when aërial hostilities seemed to be engaging more fully than even before the inventive genius of the nations, and the dash and skill of the fighting flyers, the tendency is all toward the light and swift machine.

The attitude of the fighting airmen is somewhat reminiscent of that of America's greatest sea-fighter, Admiral Farragut. Always opposed to ironclads, the hero of Mobile Bay used to say that when he went to sea he did not want to go in an iron coffin, and that when a shell had made its way through one side of his ship he didn't want any obstacle presented to impede its passing out of the other side.

The all important and even vital necessity for speed also detracted much from the value of aircraft in offensive operations. It was found early that you could not mount on a flying machine guns of sufficient calibre to be of material use in attacking fortified positions. If it was necessary for the planes to proceed any material distance before reaching their objective, the weight of the necessary fuel would preclude the carriage of heavy artillery. In the case of seaplanes which might be carried on the deck of a battleship to a point reasonably contiguous to the object to be attacked, this difficulty was not so serious. This was demonstrated to some extent by the British raids on the German naval bases of Cuxhaven and Wilhelmshaven, but even in these instances it was bombs dropped by aviators, not gunfire that injured the enemy's works. But for the airplane proper this added weight was so positive a handicap as to practically destroy its usefulness as an assailant of fortified positions.

The heavier weapons of offence which could be carried by the airplane even of the highest development were the bombs. These once landed might cause the greatest destruction, but the difficulty of depositing them directly upon a desired target was not to be overcome. The dirigible balloon enjoyed a great advantage over the airplane in this respect, for it was able to hover over the spot which it desired to hit and to discharge its bombs in a direct perpendicular line with enough initial velocity from a spring gun to overcome largely any tendency to deviate from the perpendicular. But an airplane cannot stop. When it stops it must descend. If it is moving at the moderate speed of sixty miles an hour when it drops its missile, the bomb itself will move forward at the rate of sixty miles an hour until gravity has overcome the initial forward force. Years before the war broke out, tests were held in Germany and France of the ability of aviators to drop a missile upon a target marked out upon the ground. One such test in France required the dropping of bombs from a height of 2400 feet upon a target 170 feet long by 40 broad – or about the dimensions of a small and rather stubby ship. The results were uniformly disappointing. The most creditable record was made by an American aviator, Lieutenant Scott, formerly of the United States Army. His first three shots missed altogether, but thereafter he landed eight within the limits. In Germany the same year the test was to drop bombs upon two targets, one resembling a captive Zeppelin, the other a military camp 330 feet square. The altitude limit was set at 660 feet. This, though a comparatively easy test, was virtually a failure. Only two competitors succeeded in dropping a bomb into the square at all, while the balloon was hit but once.

The character and size of the bombs employed by aircraft naturally differed very widely, particularly as to size, between those carried by dirigibles and those used by airplanes. The Zeppelin shell varied in weight between two hundred and two hundred and fifty pounds. It was about forty-seven inches long by eight and a half inches in diameter. Its charge varied according to the use to which it was to be put. If it was hoped that it would drop in a crowded spot and inflict the greatest amount of damage to human life and limb it would carry a bursting charge, shrapnel, and bits of iron, all of which on the impact of the missile upon the earth would be hurled in every direction to a radius exceeding forty yards. If damage to buildings, on the other hand, was desired, some high explosive such as picric acid would be used which would totally wreck any moderate-sized building upon which the shell might fall. In many instances, particularly in raids upon cities such as London, incendiary shells were used charged with some form of liquid fire, which rapidly spread the conflagration, and which itself was practically inextinguishable.

Shells or bombs of these varying types were dropped from airplanes as well as from the larger and steadier Zeppelins. The difference was entirely in the size. It was said that a Zeppelin might drop a bomb of a ton's weight. But so far as attainable records are concerned it is impossible to cite any instance of this being done. The effect on the great gas bag of the sudden release of a load so great would certainly cause a sudden upward flight which might be so quick and so powerful as to affect the very structure of the ship. So far as known 250 pounds was the topmost limit of Zeppelin bombs, while most of them were of much smaller dimensions. The airplane bombs were seldom more than sixty pounds in weight, although in the larger British machines a record of ninety-five pounds has been attained. The most common form of bomb used in the heavier-than-air machines was pear-shaped, with a whirling tail to keep the missile upright as it falls. Steel balls within, a little larger than ordinary shrapnel, are held in place by a device which releases them during the fall. On striking the ground they fall on the explosive charge within and the shell bursts, scattering the two or three hundred steel bullets which it carries over a wide radius. Bombs of this character weigh in the neighbourhood of six pounds and an ordinary airplane can carry a very considerable number. Their exploding device is very delicate so that it will operate upon impact with water, very soft earth, or even the covering of an airship. Other bombs commonly used in airplanes were shaped like darts, winged like an arrow so that they would fall perpendicularly and explode by a pusher at the point which was driven into the body of the bomb upon its impact with any hard substance.

It seems curious to read of the devices sometimes quite complicated and at all times the result of the greatest care and thought, used for dropping these bombs. In the trenches men pitched explosive missiles about with little more care than if they had been so many baseballs, but only seldom was a bomb from aloft actually delivered by hand. In the case of the heavier bombs used by the dirigibles this is understandable. They could not be handled by a single man without the aid of mechanical devices. Some are dropped from a cradle which is tilted into a vertical position after the shell has been inserted. Others are fired from a tube not unlike the torpedo tube of a submarine, but which imparts only slight initial velocity to the missile. Its chief force is derived from gravity, and to be assured of its explosion the aviator must discharge it from a height proportionate to its size.

In the airplane the aviator's methods are more simple. Sometimes the bombs are carried in a rack beneath the body of the machine, and released by means of a lever at the side. A more primitive method often in use is merely to attach the bomb to a string and lower it to a point at which the aviator is certain that in falling it will not touch any part of the craft, and then cut the string. Half a dozen devices by which the aviator can hold the bomb at arm's length and drop it with the certainty of a perpendicular fall are in use in the different air navies. It will be evident to the most casual consideration that with any one of these devices employed by an aviator in a machine going at a speed of sixty miles an hour or more the matter of hitting the target is one in which luck has a very great share.

There is good reason for the pains taken by the aviators to see that their bombs fall swift and true, and clear of all the outlying parts of their machines. The grenadier in the trenches has a clear field for his explosive missile and he may toss it about with what appears to be desperate carelessness – though instances have been known in which a bomb thrower, throwing back his arm preparatory to launching his canned volcano, has struck the back of his own trench with disastrous results. But the aviator must be even more careful. His bombs must not hit any of the wires below his machine in falling – else there will be a dire fall for him. And above all they must not get entangled in stays or braces. In such case landing will bring a most unpleasant surprise.

A striking case was that of a bomber who had been out over the German trenches. He had a two-man machine, had made a successful flight and had dropped, effectively as he supposed, all his bombs. Returning in serene consciousness of a day's duty well done, he was about to spiral down to the landing place when his passenger looked over the side of the car to see if everything was in good order. Emphatically it was not. To his horror he discovered that two of the bombs had not fallen, but had caught in the running gear of his machine. To attempt a landing with the bombs in this position would have been suicidal. The bombs would have instantly exploded, and annihilated both machine and aviators. But to get out of the car, climb down on the wires, and try to unhook the bombs seemed more desperate still. Stabilizers, and other devices, now in common use, had not then been invented and to go out on the wing of a biplane, or to disturb its delicate balance, was unheard of. Nevertheless it was a moment for desperate remedies. The pilot clung to his controls, and sought to meet the shifting strains, while the passenger climbed out on the wing and then upon the running gear. To trust yourself two thousand feet in mid-air with your feet on one piano wire, and one hand clutching another, while with the other hand you grope blindly for a bomb charged with high explosive, is an experience for which few men would yearn. But in this case it was successful. The bombs fell – nobody cared where – and the two imperilled aviators came to ground safely.

A form of offensive weapon which for some reason seems peculiarly horrible to the human mind is the fléchette. These are steel darts a little larger than a heavy lead pencil and with the upper two thirds of the stem deeply grooved so that the greater weight of the lower part will cause them to fall perpendicularly. These are used in attacks upon dense bodies of troops. Particularly have they proved effective in assailing cavalry, for the nature of the wounds they produce invariably maddens the horses who suffer from them and causes confusion that will often bring grave disaster to a transport or artillery train. Though very light, these arrows when dropped from any considerable height inflict most extraordinary wounds. They have been known to penetrate a soldier's steel helmet, to pass through his body and that of the horse he bestrode, and bury themselves in the earth. In the airplane they are carried in boxes of one hundred each, placed over an orifice in the floor. A touch of the aviator's foot and all are discharged. The speed of the machine causes them to fall at first in a somewhat confused fashion, with the result that before all have finally assumed their perpendicular position they have been scattered over a very considerable extent of air. Once fairly pointed downward they fall with unerring directness points downward to their mark.