Airfare of to-day and of the future

Front matter

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OF TO-DAY AND OF THE FUTURE

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Contents

CHAPTER

I. The Navigation of the Air

II. Climatic and Geographical Conditions

CHAPTER I THE NAVIGATION OF THE AIR The Surface of the Earth

A MAP of the surface of the earth is to many people hardly more distinguishable than a Chinese love-letter or the American Morse Code. The markings are crudely unmistakable ; but a maze of colours and angles and shapes. Yet this same evil contraption, given the geographical position of the North, and a distinguishable point on the surface of the earth, is simple to read as an open book. With the airman, however, the angle of perspective is different and certainly more bewildering. He has no single point but the entire earth at his feet, stretching away to the oblivion of the sky-line in the direction of every point of the compass. The general position is harder to grasp, and map making and reading form no small part in the curriculum of his education. While navigation is as important to him as it is to the sailor. j$ -

There is much in common between sea and air. The elements are similar. The traditions and precedents of the older Service will, in time, apply equally to either.

With regard to navigation and pilotage the main differences are : whereas the view of the sea navigator is on the level, that of his brother of the air lies always below and covers an extremely wide area.

What does the surface of the earth look like viewed from above ? The first view over the side is both curious and bewildering. It is a Lilliputian world, over which swarm numerous ant-like figures. It is pleasing to the eye ; a regular, unorthodox riot of colours. The colour scheme strikes one more than any other element. The grouping of towns and cities, villages and hamlets is peculiar. The roads and railways in the more populous districts intermingle in puzzling fashion. Naturally the sharpest division is that between land and sea. The blue of the one borders the grey of the other, with a thin dividing line of yellow sand of the foreshore. This yellow on the sea fringe is conspicuous : and from a certain altitude over the sea the bed is thrown up in bold relief.

These details are all supplied in the contour maps. But the map to the airman is more than a voiceless jumble of shapes and colours. It bespeaks a glorious panorama of brown-smudged altitudes, blue-lined rivers, green-tinted plains, grey-blotted towns and villages, straight, black-lined railways, that are criss-crossed into squares to be criss-crossed again, and given ugly appellations as Ac 31, Df 22, maps that are to be read only by compass and by scale.

Piecing together the intermediate colours in the grey background of the land, we have, most conspicuous, the blue of the rivers and lakes. As landmarks they are the most easily distinguishable,

THE NAVIGATION OF THE AIR 3

excepting in wet weather, when they overflow their banks and change materially the appearance of the country for miles around. Next in order of importance are rail way- tracks, distinguishable by reason of their regularity and directness ; they connect up the principal centres of population like network. Tunnels are at times apt to be disconcerting. The track will disappear from view for half a mile or so. But here again reference to the map soon enables the pilot to pick up the broken thread.

Large towns and populous districts are unmistakable. The key to their identity is the plan of the diverging lines of roads, rivers and railways.

Passing to the open country, woods are conspicuous, but above an altitude of 2500 they present the surface of a level meadowland. Fields of crops differ in shade with the varying seasons of the year. Wheat in summer presents a golden-yellow appearance ; in autumn, brown ; in spring, green. Stubble fields are lightish brown in appearance, and dark green fields are usually found to be roots.

Roads follow almost exactly the system of railways. First-class or main roads are easily distinguishable from their width, the blue steelish appearance of their surface, and the lines of telegraph and telephone wires along either side. The old Roman roads in England are most easily distinguishable by reason of their directness. Among other conspicuous objects are golf-links ; the greens and the yellow sand-bunkers stand out prominently, and glass-houses that glitter dazzlingly in the sun.

Above an altitude of two thousand five hundred and three thousand feet the entire surface of the earth, hill and valley, wood and field, appear to be at the same level. Landmarks are most difficult to distinguish when flying either at an extremely low or extremely high altitude. The time on sunny, cloudless days passes with great rapidity ; in dull, cloudy weather it drags, until the seconds seem minutes, and the minutes hours. The natural course of the machine is never a direct one. It is apt, first, to veer to the left, then to return to the direct course, and then branch off again to the right.

Factory chimneys and railway locomotives are useful to the air pilot. Their smoke indicates the direction of the prevailing wind, so necessary in the matter of landing the aeroplane, which must be performed head against the wind, as also getting off from the ground.

The difficulty of aerial navigation may be gauged from the fact that a pilot recently lost his way when flying between Hendon and Chingford. Another affair of the same kind was the cause of numerous questions in the House of Commons, and concerned an aeroplane of the latest type that had been flown across Channel to the firing-line, and landed in the enemy's country on its first trip. A German pilot, in similar fashion, flew down the Belgian coast, and landed at Calais in mistake for Ostend, there to be promptly made a prisoner. And yet another instance is on record of an R.F.C. pilot who, setting out one fine morning from somewhere in Kent, ran into a dense bank of fog, and eventually landed in Norfolk. Unaccustomed to the broad dialect of the natives, he imagined for the moment that he had found his way across Channel and landed in the German lines, and was about to set fire to his machine when he discovered his happy mistake.

The majority of these errors can be avoided by reference to the map and the use of the altimeter, another name for which is the statoscope. This instrument is contained in a large metal case and registers the altitude in hundreds of feet. Beneath

THE NAVIGATION OF THE AIR 5

the face is an opening, into which is fitted a taut rubber membrane, with a small rubber tube leading to the outer air. By pinching the latter between the fingers, the outer air is excluded from the membrane. When the craft ascends, the air in the statoscope will expand, when it descends it will contract. Contraction or expansion both react on the rubber membrane, which will be sucked inward in descending, and when ascending be blown outwards. By means of delicate internal machinery these movements are conveyed to the indicator hand on the disc. But the altimeter only registers height above sea-level.

Thus an airman setting off from an aerodrome that lies some 2000 feet above the level of the sea, would fly on with the altimeter registering, let us say, four thousand feet ; yet in reality he would only be two thousand above the level of the land, and in constant danger of collision with altitudes on the surface of over two thousand feet.

The matter of altitude varies considerably with the nature of the flying. For war work, usually well over 8000 ; for commercial purposes, anything from between 2000 to 6000 feet. The greater the altitude the safer is the flying. The engine of a machine failing at a height of 8000 leaves the pilot a radius of, roughly, ten square miles in which to choose a landing-place ; at 9000, twelve square miles ; and at 10,000 ten, and so forth.

A comparison between the altitudes of the highest mountain peaks of the world and flying offers matter for interesting thought. We discover that the war altitude of flying ranges from the height of the Catskill Mountains to the peak of Teneriffe, and that the crest of Mount Everest is double the height of the present-day flying altitude. We have no great mountains in this country, but the hills tower sufficiently to form a continual danger to passing aircraft. No doubt in time to come such danger spots will be topped by aerial lighthouses and beacons.

Contour, from the airman's point of view, is the important characteristic of the map.

A map after the style of the Mercator's Chart would be an ideal map for the air. It would be constructed on the following principle. The Rhumb

Everest ,

Dhdwalag'tri Aconcagua j

Altitude

10,000 5,000

EifTel Tower

FIG.

A COMPARISON OF FLYING HEIGHTS lines on the earth's surface would be represented by straight lines on the chart. And angles on the earth's surface would be equal to the corresponding angles on the chart. The only markings would be contour, roads, railways, rivers, and towns.

A map of London on this principle would appear after the fashion of Fig. 2.

Laws of the Air

Naturally so vast an area as the air calls for special regulations and laws. And as long since as 1902 a conference of balloonists met at Brussels.

THE NAVIGATION OF THE AIR 7

The meeting devoted the better part of the time to discussing the differences between military and civilian types of craft, the use of a distinguishing flag for each craft, and the organization of the lately formed Federation Aeronautique Internationale, a body that now governs aeronautical matters of

FIG. 2. HOW LONDON APPEARS FROM ABOVE

almost every nation of the world, and to which is affiliated our Royal Aero Club.

The latter institution has been instrumental in drawing up various rules and regulations regarding flying in Great Britain, the majority of them as a safeguard to the aviator himself. For instance, to avoid collision in mid- air : " Two aircraft meeting each other, end on, and thereby running the risk of a collision, must always steer to the right. They must, in addition to this, pass at a distance of at least ioo metres, taken between their nearest adjacent points.

" Any aircraft overtaking another aircraft is responsible for keeping clear, and must not approach within ioo metres on the right, or 300 metres on the left of the overtaken aircraft ; and must not pass directly underneath, or over, such overtaken aircraft. The distance shall be taken between the nearest adjacent points of the respective aircraft. In no case must the overtaking aircraft turn in across the bows of the other aircraft after passing it so as to foul it in any way."

Again, the R.A.C. issued the following notice : —

" Flying to the danger of the public is prohibited, particularly unnecessary flights over towns or thickly populated areas, or over places where crowds are temporarily assembled, or over public enclosures, or aerodromes at such a height as to involve danger to the public. Flying is also prohibited over river regattas, race meetings, meetings for public games and sports, except flights specifically arranged for in writing with the promoters of such regattas, meetings, etc. Any disregard of the above prohibitions will render the aviator liable to censure, fine not exceeding £20, suspension of the competitor's certificate, and removal from the competitors' register/ '

In 1913 the Government passed the Aerial Navigation Act, that dealt with the specified areas over which the navigation of " every class and description of aircraft " was prohibited. These areas comprised dockyards, fortresses, arsenals, harbours and barracks.

" No aircraft from abroad is allowed to make a

THE NAVIGATION OF THE AIR g

landing in this country, except in special areas. The person in charge of such aircraft must be in possession of a clearance of a British consular officer from the country in which the voyage was commenced.

11 No person in any aircraft entering the United Kingdom shall carry or allow to be carried in the aircraft (a) Any goods, the importation of which is prohibited by the law relating to customs. (6) Any goods chargeable upon importation into the United Kingdom with any duty of Customs, except such small quantities as have been placed on board at the place of departure as being necessary for the use during the voj/age of the persons conveyed therein. (c) Any photographic apparatus, carrier or homing pigeons, explosives or fire-arms; and (d) Any mails.

1 The person in charge of the aircraft shall not continue his voyage until he has obtained a permit from the authorized officer, for which a fee of £3 will be payable in the case of an airship and £1 in case of an aeroplane.

" Foreign naval or military aircraft shall not pass over or land within any part of the United Kingdom or the territorial waters thereof except on the express invitation, or with the express permission, previously obtained, of His Majesty's Government. Such aircraft shall enjoy such exemptions from the foregoing Orders and be subject to such special conditions as may be specified in the invitation or permission.

" Nothing in the foregoing Orders shall be construed as conferring on a person navigating an aircraft any right to land in any place as against the wishes of the owner of the land or other persons interested therein, or as affecting the rights or remedies of any person in respect of any injury to persons or property caused by any aircraft.

lo AIRFARE

" Any person navigating an aircraft in contravention of the foregoing Orders is liable on conviction to imprisonment for six months or to a fine of £200, or to both imprisonment and fine."

Navigation and Pilotage

Of the various zones, tropical and sub-tropical lend themselves more easily to aviation. The explanation is that the weather there is more reliable. The various seasons are more sharply defined. There is no unpleasant intermingling of calm and stormy weather. To a degree one may be certain twenty-four hours previous what the weather conditions promise to be. And the tepid air is favourable to aviation, never the warmest of professions.

Per contra the difficulties encountered in a temperate zone, as the one within which this country lies, are enormous. Rain, sun, snow, fog, all are possible within the incredibly short space of twenty-four hours. For days on end flying will be impossible, and the pilot thus kept idle and useless.

Closely akin to this matter of weather is the contrast between night and day flying. It is common knowledge that flying is mostly confined to daylight. The darkness holds many different dangers and terrors. First, the surface of the earth is lost to view. This intensifies the dangers of landing, always a hazardous enterprise. To some extent this difficulty is overcome by the use of landing flares, which in a darkened country stand out with prominence. The most favourable of these nightlighting schemes is that recently adopted by the enemy.

A large white light is placed in the centre of the landing-ground, sunk into a trench in the ground

THE NAVIGATION OF THE AIR il

and covered with thick glass to withstand the weight of an aeroplane. At a distance of about 250 feet from this light, and also sunk into the ground, are four red lights corresponding to the cardinal points of the compass. Each of the red lights is connected by subterranean cables to a windvane, mounted on a mast or tower at some convenient point. At night the central light glows constantly, while the red light in the direction of the wind indicates to the pilot the wind conditions where the landing is to be made. It is understood that a system of altering the lights has been devised, so that an aviator must understand the code in order to know his whereabouts. Thus enemy airmen are prevented from using the lights as guides.

Another method is to extinguish the lights immediately the pilot has left the ground and wait for his return signal before relighting them. This signalling is performed by firing a bullet of a certain colour from a Very's pistol at a low altitude.

However, night flying is an art in itself, and is only permitted to experienced pilots ; the principal reason being, as previously mentioned, that darkness obliterates all landmarks, which brings us to the matter of pilotage and navigation.

The former is accomplished by the aid of landmarks and the map ; a compass is unnecessary. On the other hand, navigation is steering a course out of sight of landmarks by compass. And though the compass is said to be the best friend of the sailor, yet more so is it of the airman.

It is a similar instrument to that employed on a ship. The variation— that changes slightly every year — is similar ; also the deviation — this latter being a matter to do with the metal in the framework and the engine of the machine, which is in manner similar to the natural magnetism in the earth that causes the variation of the compass needle from true to the magnetic north. Deviation again varies the compass further from the true north, and is compensated for by the arrangement of certain magnets that draw the needle back to the correct position.

Later we learn, vide the Scientific American, of the invention of an airman's compass which is visible at night by its own light. With this compass " a knowledge of navigation is not essential for laying a course. The first step is to set the instrument upon the chart at. the spot indicating the user's location. The zero mounting of the outer ring, in line with the arrow point on the glass crystal, should point toward the north or top of the map. Any course desired (or the direction to be travelled in going from one location to another) may be found by elevating, to an angle of 45 degrees, the arm of metal attached to the outer ring and then sighting over its top and the niche in the magnifying glass bezel ring to a pin stuck in the chart at the point of destination. Such a process illustrates one important advantage of this compass over similar instruments, namely, that parallel rules for sighting are unnecessary and may be dispensed with.

" In order to travel from any location to a particular destination it is essential to apply the magnetic variation. With other compasses it is necessary to add or subtract this magnetic difference, depending upon whether the variation is westerly or easterly. Doing so gives the magnetic head to be travelled, read on the centre dial in the bowl. In using this compass, however, both adding and substracting are done away with. It is merely necessary to move the lubber's line, indicated by a white line and

THE NAVIGATION OF THE AIR 13

arrow painted on the crystal, to the point of destination. This line becomes the lubber's line to be followed in actual travel.

" The present compass, measuring an inch and a quarter thick and two and three-quarter inches in diameter, contains no steel except that in the magnet, so the needle cannot become deranged by being attracted to another part of the compass. The bowl is made of bronze and painted, while the fittings are of brass. A magnifying glass, mounted in the bezel ring and fitted over the dial, enlarges the figures on the latter so that they may be read more easily. A nickel ring attached to the outside of the bowl is for convenience in carrying the instrument with a strap, if desired.

11 To increase the accuracy of this compass, the card is mounted in a mixture of alcohol and distilled water, thus rendering the magnetic float more buoyant and sensitive. The markings on this compass are readable at night in the light from the radium dial, which is graduated every 5 degrees and numbered every 20 degrees. The last zero is omitted in all numbers to avoid crowding.' '

Another deterrent to flying an accurate course are cross-currents of air. To avoid this difficulty, it is usual for the pilot to plot out a true course by mathematics preparatory to leaving the ground, making due allowance for the cross-currents and the mileage. Inappropriate word ! Despite the fact that aerial is so remarkably similar to sea navigation, the R.F.C. still persist in talking of flying at so many miles an hour. How much better it would sound than saying : an aeroplane was making fifty miles an hour, to say, it was making forty-five knots — never knots an hour. A knot is equivalent, roughly, to 6080 feet or 2026 yards.

So much for to-day. In the future, within the space of a very few years we will find beaten tracks in the air as to-day they lie across the great oceans. There will be special trade routes and commercial tracks. But they will, without exception, all lie eastward of the United Kingdom.

Chapter II Climatic And Geographical Conditions

AVIATION develops more and more day by day. jf"Y To the uninitiated such development is regarded with interest, but not appreciation. This by reason of the strenuous times in which we live, and the necessary military secrecy which prohibits public discussion concerning the development of the various craft. To the man in the street aviation provides a pleasing interlude to the grim chorus of war. It is spectacular, thrilling, heroic ! Beyond that it is not realized that the aeroplane and airship are no longer units but decisive factors in battle. Yet the air is common to all. To every Power that has the necessary craft it provides a free highway, for good or evil. And what is common to all cannot be held by all. One alone can control. In time past it was the sea that was the common element. From the time of the Roman Empire the dominating Powers of the world have held the sea before conquering the land, and, incidentally, been possessed of ample seaboards. Spain is witness to the latter fact, as also France, and later our own Empire. We mastered the sea : we mastered the world ! Now the air, by reason of its accessibility, has superseded the sea. In the future, the mastery of the air must mean the dominion of the world.

But before further discussion it will be well to consider the types of craft. They are three in number : aeroplane, seaplane, and airship. The former operates entirely over land ; the seaplane, as its name would imply, over the sea ; and the latter, over both land and sea. Which of the three offer greater possibilities in the future ? For the nonce we will adopt the aeroplane, by reason of its already extensive field of operations.

Studying the map of the world, from the point of view of the air, what do we discover ? Not five continents and five oceans, but one great tract of land that stretches from Hammerfest in the north to Capetown in the south, westward to Lisbon, eastward to Vladivostock, comprising three entire continents. For the rest the main group is surrounded by the great oceans, in which lie the distant continents of Australasia and America.

How does this redistribution affect Great Britain ? Our islands will lie on the extreme western edge of civilization. No longer will the activities of the world turn on a hub so distant from the centre. No longer will this country be an island. For many years to come the uncertain climatic conditions of the Atlantic Ocean will protect our western shores. But to the east we shall be at the mercy of the world. In the future our lines of communication, our lines of supply, will all lie eastward.

To-day the radius of aircraft is roughly 150 miles, with airships 300. Already many of our cities, manufacturing centres, and positions of military importance lie within easy reach of Amsterdam, Paris, and Brussels. When that aeroplane radius extends to three, and the Zeppelin to 600, it will include Metz, Cologne, Bremen, Milan, Berne, Innsbruck, Vienna, Berlin, Hamburg, Copenhagen, Saragossa (Spain), Christiania, and Bergen (Norway).

World supremacy for us then will be mastery of

GEOGRAPHICAL CONDITIONS 17

the air. Such mastery can only be achieved with an unceasing, unlimited supply of money and craft. And the future of aircraft lies in the hands of the constructors. Insufficient encouragement will entail the loss of valuable ideas and future prestige. With regard to the actual flying, aircraft are affected by climatic conditions even more than sea vessels. The latter have land-sheltered harbours to anchor from the gale. For the airman is no refuge. Inclement weather renders flying impossible.

Of all these elements, wind affects flying most. It is a matter to do with the speed of the craft over the surface of the earth. The speedometer of an aeroplane may register 80 m.p.h., but is influenced solely by the power of the engine. In reality the speed of that machine might be ten miles over the ground, that is to say it might be flying ten miles in a backward direction. The wind against which it is flying is one of ninety miles, or ten more per hour than its maximum speed.

Fog is a most dangerous condition to the airman. Once in a fog he loses all sense of direction and proportion. Earth and sky, and all landmarks are alike obliterated. Rain is blinding to the eyes, and affects the lift of the machine. And snow covers the surface of the earth with a treacherous regularity, rendering the landing of an aeroplane both dangerous and difficult.

But perhaps the most curious phenomenon of the air is the " bump " that causes the aeroplane to toss and heave like a boat in a stormy sea, and sends it plunging downward, sometimes as much as 200 feet. These bumps are caused by diverging currents of air. It is not generally known that there are currents in the air, just as there are currents in the sea. The explanation of the cause is simple. The night is always cooler than the day, but the earth retains more of its warmth than does the air. The latter, by the morning, in spring, summer and autumn is quite chilly, in winter icy cold. When the sun rises the rays beat down upon the earth, warming perceptibly the strata of air through which they pass. The earth is more quickly warmed, and the heat which it irradiates warms the layer of air immediately above it.

This hot air commences to expand and rises, forming a vertical column of warm air which, forcing its way upwards, meets with considerable resistance from the cold air which it must traverse, and which is denser and therefore firmer. In order to effect its ascent the warm air begins to work its way spirally, like a drill, or like smoke rising from the funnel of a steamer. Thus a hot day following a cool night produces a choppy sea of air.

The manner of this current which the airman encounters largely depends upon the physiognomy of the country over which he is flying. Over a forest or wooded country the flying is quiet and placid, because the leaves, saturated with moisture, are reservoirs of coolness and are warmed very slowly by the sun, and even when warm do not radiate much heat. A sandy beach, on the other hand, or a desert, is warmed very quickly, and in consequence the air above it rises in rapid spirals.

Sandy tracts separating wooded countries are always troublesome. The cool air of the woods pours down upon the hot air of the sandy tracts, the hot air in the meanwhile trying its best to escape to higher regions. The commotion may be imagined. The movement which the aeroplane undergoes over so diversified a surface may be compared to a continuous switchback. Powerless to resist these currents, all the aviator can do is to steer his craft, allowing the winds to carry him up or down.

GEOGRAPHICAL CONDITIONS 19

The little islands of white cloud seen in blue and golden summer days are the lighthouses of the air. They signal danger to the airman. They are the tops of spirally ascending warm columns of air, and, just like a fountain, the cold air pours down on either side of the hot air.

If the airman has been drawn into such a fountain and escapes with his life, he can count his escape as marvellous. Almost invariably if he traverses such a geyser of air his machine turns turtle owing to the fact that the cold air pushes one side of his machine down, while the hot air pushes the other side up.

Bumps, however, are encountered only in the lower altitudes. Higher up they are replaced by clouds if anything more dangerous. In a cloud an aeroplane loses stability, which frequently ends with a nose-dive. These clouds vary at differing altitudes. Up to an altitude of 3500 feet the most prevalent clouds are Stratus, filmy and greyish white in colour. From 3000 to 6400 feet are Nimbus, or rain clouds. Cumulo-Nimbus, or storm clouds, are prevalent between an altitude of 4500 to 24,000 feet. From 10,000 to 23,000 feet are Cirro-Cumulus or " Mackerel Sky," and above 27,000 and up to 50,000 feet are Cirrus, or " Mare's Tail."

Above the clouds there is smoother sailing. Normal conditions prevail frequently. The warm air driving upward with uniform strength and wide layers makes an excellent medium for aircraft. If, however, there is a break in the clouds the airman must exercise the utmost prudence. Above such a break in the clouds there is no warm air to uphold the aeroplane. The air has been sucked away from this spot, and the rarefied air that remains cannot carry the machine.