The War in the Air; Vol. 1 / The Part played in the Great War by the Royal Air Force

by Sir Walter Alexander Raleigh

Under the direction of the Air Department much attention was paid by pilots in the Naval Air Service to experimental work and the diverse uses of aeroplanes. So early as January 1912 Lieutenant H. A. Williamson, R.N., a submarine officer who had gained the Royal Aero Club certificate, submitted to the Admiralty a paper which anticipated some later successes. He advocated the use of aeroplanes operating from a parent ship for the detection of submarines, and showed how bombs exploding twenty feet below the surface might be used to destroy these craft. The practical introduction of depth charges was delayed for years by the difficulty of devising the delicate and accurate mechanism which uses the pressure of the water to explode the bomb at a given depth. But before the war ended the detection of submarines from the air and the use by surface craft of depth charges for destroying them had been brought to such a degree of efficiency that the submarine menace was countered and held. The submarine learned to fear aircraft as the birds of the thicket fear the hawk. It would be tedious to attempt to describe the long series of experiments by which this result was at last attained. The earliest attempts to detect submarines from the air were made with seaplanes at Harwich in June 1912, and at Rosyth in September of the same year. The shallow tidal waters were found to be very opaque, but in clear weather a periscope could be seen from a considerable distance, and in misty weather the seaplane, when it sighted a submarine in diving trim on the surface, could swoop down and drop a bomb before the submarine could dive.

Progress in bomb-dropping was not less. Nothing is easier than to drop a detonating bomb, with good intentions, over the side of an aeroplane; the difficulty of hitting the mark lay in determining the flight of the bomb and in devising an efficient dropping gear. To drop a weight from a rapidly moving aeroplane so that it shall hit a particular spot on the surface of the earth is not an easy affair; the pace and direction of the machine, its height from the ground, the shape and air resistance of the bomb, must all be accurately known. They cannot be calculated in the air; success in bomb-dropping depends on the designing of a gear for dropping and sighting which shall perform these calculations automatically. Very early in the history of aviation dummy bombs had been dropped, for spectacular purposes, at targets marked on the ground. The designing of an efficient dropping gear and the study of the flight of bombs were taken up by the Air Department of the Admiralty from the very first. Under their direction a very valuable series of experiments was carried out at Eastchurch, at first by Commander Samson, and later by Lieutenant R. H. Clark Hall, a naval gunnery lieutenant, who had learnt to fly, and was appointed in March 1913 for armament duties with the Royal Naval Air Service.

The whole subject was new. No one could tell exactly how the flight of an aeroplane would be affected when the weight of the machine should be suddenly lightened by the release of a large bomb; no one could be sure that a powerful explosion on the surface of the sea would not affect the machine flying at a moderate height above it. In 1912 a dummy hundred-pound bomb was dropped from a Short pusher biplane flown by Commander Samson, who was surprised and pleased to find that the effect on the flight of the machine was hardly noticeable. In December 1913 experiments were carried out to determine the lowest height at which bombs could be safely dropped from an aeroplane. No heavy bombs were available, but floating charges of various weights, from 2-1/4 pounds to 40 pounds, were fired electrically from a destroyer, while Maurice Farman seaplanes flew at various heights directly above the explosion. Again the effect upon the machines was less than had been anticipated. The general conclusion was that an aeroplane flying at a height of 350 feet or more could drop a hundred-pound bomb, containing forty pounds of high explosive, without danger from the air disturbance caused by the explosion.

A good war machine aims at combining the safety of the operator with a high degree of danger to the victim. The second of these requirements was the more difficult of fulfilment, and was the subject of many experiments. Until the war took the measure of their powers, the German Zeppelins preoccupied attention, and were regarded as the most important targets for aerial attack. The towing of an explosive grapnel, which, suspended from an aeroplane, should make contact with the side of an airship, was the subject of experiments at Eastchurch. This idea, though nothing occurred to prove it impracticable, was soon abandoned in favour of simpler methods—the dropping, for instance, of a series of light bombs with sensitive fuses, or the firing of Hales grenades from an ordinary service rifle. To make these effective, it was essential that they should detonate on contact with ordinary balloon fabric, and preliminary experiments were carried out at the Cotton Powder Company's works at Faversham in October 1913.

When two sheets of fabric, stitched on frames to represent the two skins of a rigid airship, were hit by a grenade of the naval type with a four-ounce charge, it was found that the front sheet was blown to shreds and the rear sheet had a hole about half a foot in diameter blown in it. Later experiments at Farnborough against balloons filled with hydrogen, and made to resemble as nearly as possible a section of a rigid airship, were completely successful. Firing at floating targets, and at small target balloons released from the aeroplanes, was practised at Eastchurch. It was found that, with no burst or splash to indicate where the shot hit, this practice was unprofitable. The effective use of small-bore fire-arms against aircraft was made possible by two inventions, produced under the stress of the war itself, that is to say, of the tracer bullet, which leaves behind it in the air a visible track of its flight, and of the incendiary bullet, which sets fire to anything inflammable that it hits.

At the outbreak of war the only effective weapon for attacking the Zeppelin from the air was the Hales grenade. Of two hundred of these which had been manufactured for the use of the Naval Wing many had been used in experiment; the remainder were hastily distributed by Lieutenant Clark Hall among the seaplane stations on the East Coast.

The Naval Air Service experimented also with the mounting of machine-guns on aeroplanes. On this matter Lieutenant Clark Hall, early in 1914, reported as follows:

'Machine-gun aeroplanes are (or will be) required to drive off enemy machines approaching our ports with the intention of obtaining information or attacking with bombs our magazines, oil tanks, or dockyards.... I do not think the present state of foreign seaplanes for attack or scouting over our home ports is such as to make the question extremely urgent, but I would strongly advocate having by the end of 1914 at each of our home ports and important bases at least two aeroplanes mounting machine-guns for the sole purpose of beating off or destroying attacking or scouting enemy aeroplanes.'

From what has been said it is evident that the Naval Wing of the Royal Flying Corps paid more attention than was paid by the Military Wing to the use of the aeroplane as a fighting machine. This difference naturally followed from the diverse tasks to be performed by the two branches of the air service. The Military Wing, small as it was, knew that it would be entrusted with the immense task of scouting for the expeditionary force, and that its business would be rather to avoid than to seek battle in the air. The Naval Wing, being entrusted first of all with the defence of the coast, aimed at doing something more than observing the movements of an attacking enemy. Thus in bomb-dropping and in machine-gunnery the Naval Wing was more advanced than the Military Wing. Both wings were active and alive with experiment, so that after a while experimental work which had originally been assigned to the factory and the Central Flying School was transferred to the Wing Headquarters. During the year 1913 wireless experiments were discontinued at the Central Flying School, and were concentrated at the Military Wing. There was a valuable measure of co-operation between the two wings. This co-operation was conspicuous, as has been seen, in wireless telegraphy, which was first applied to aircraft at Farnborough. The lighter-than-air craft, which belonged first to the army and then to the navy, were a valuable link between the two wings. Each wing was ready to learn from the other. In January 1914, by permission of the Admiralty, officers of the Military Wing witnessed the experiments made by the Naval Wing with bomb-dropping gear. If the Naval Wing in some respects made more material progress, it should be remembered that they received more material support. They were encouraged by the indefatigable Director of the Air Department, and received from the Admiralty larger grants of money than came to the Military Wing. No doubt a certain spirit of rivalry made itself felt. Service loyalty is a strong passion, and the main tendency, before the war, was for the two branches of the air service to drift apart, and to attach themselves closely, the one to the army, the other to the navy.

At the end of 1913 H.M.S. Hermes was paid off, and the headquarters of the Naval Wing was transferred to the Central Air Office, Sheerness. All ranks and ratings hitherto borne on the books of the Hermes were transferred to the books of this newly created office, and Captain F. R. Scarlett, R.N., late second in command of the Hermes, was placed in charge, with the title of Inspecting Captain of Aircraft. He was responsible to the Director of the Air Department, and, in regard to aircraft carried on ships afloat, or operating with the fleet, was also directly responsible to the Commander-in-Chief of the Home Fleets. In some respects the progress made by the Naval Wing of the Royal Flying Corps during 1913 had been continuous and satisfactory. Training had been carried on regularly at the Central Flying School, at Eastchurch, and, for airship work, at Farnborough. By the end of the year there were about a hundred trained pilots. Stations for guarding the coast had been established in five places other than Eastchurch, and arrangements were in hand for doubling this number. The record of miles flown during the year by naval aeroplanes and seaplanes was no less than 131,081 miles. Wireless telegraphy had made a great advance; transmitting sets were in course of being fitted to all seaplanes, and the reception of messages in aeroplanes had been experimentally obtained. Systematic bomb-dropping had been practised with growing accuracy and success. A system for transmitting meteorological charts from the Admiralty, so that air stations and aircraft in the air should receive frequent statements of the weather conditions, had been brought into working order.