CHAPTER VIIThe Arrival

GasolineA SPECIAL KIND OF GASOLINE HAD TO BE USED

A SPECIAL KIND OF GASOLINE HAD TO BE USED

All aboardALL ABOARD FOR THE FIRST TRIAL FLIGHT

ALL ABOARD FOR THE FIRST TRIAL FLIGHT

But once again we were lucky. At a height of five hundred feet the Vickers-Vimy emerged from the pall of cloud, and we saw the ocean—arestless surface of dull gray. Alcock at once opened up the throttles, and both motors responded. Evidently a short rest had been all that the starboard motor needed when it began to pop, for it now gave no further signs of trouble.

I reached for the Drift Bearing Plate, and after observation on the ocean, found that we were moving on a course seventy-five degrees true, at one hundred and ten knots ground speed with a wind of thirty knots from the direction of two hundred and fifteen degrees true. I had been reckoning on a course of seventy-seven degrees true, with calculations based on our midnight position; so that evidently we were north of the prescribed track. Still, we were not so far north as to miss Ireland, which fact was all that mattered to any extent.

In my correction of the compass bearing, I could only guess at the time when the wind had veered from its earlier direction. I made the assumption that the northerly drift had existed ever since my sighting on the Pole Star and Vega during the night, and I reckoned that our position at eight o'clock would consequently be about fifty-four degrees N. latitude, ten degrees thirty min. W. longitude. Taking thesefigures, and with the help of the navigation machine, which rested on my knees, I calculated that our course to Galway was about one hundred and twenty-five degrees true. Allowing for variation and wind I therefore set a compass course of one hundred and seventy degrees, and indicated to the pilot the necessary change in direction by means of the following note and diagram:

"Make course

"Don't be afraid of going S. We have had too much N. already."

Alcock nodded and ruddered the Vickers-Vimy around gently, until its compass showed a reading of 170 degrees.

My calculations, if correct, proved that we were quite close to Ireland and journey's end.As we flew eastward, just below the lowest clouds and from two hundred to three hundred feet above the sea, we strained our eyes for a break in the monotonous vista of gray waves; but we could find not even a ship.

Although neither of us felt hungry, we decided to breakfast at eight o'clock, partly to kill time and partly to take our minds from the rising excitement induced by the hope that we might sight land at any instant. I placed a sandwich, followed by some chocolate, in Alcock's left hand. His right hand remained always on the control lever and his feet on the rudder bar.

At no time during the past sixteen hours had the pilot's hands and feet left the controls. This was a difficult achievement for such a long period, especially as a rubber device, fitted to ease the strain, proved to be valueless. Elastic, linked to a turnbuckle, had been attached to the control lever and rudder bar; but in the hurry that preceded our departure from St. John's, the elastic was cut too short. All the weight of the controls, therefore, bore directly on the pilot.

The machine now tended to sag downward, being nose-heavy because its incidence hadchanged, owing to the gradual alteration in the center of gravity as the rear gasoline tanks emptied. Alcock was thus obliged to exert continuous backward pressure on the control lever.

I had screwed on the lids of the thermos flask, and was placing the remains of the food in the tiny cupboard behind my seat, when Alcock grabbed my shoulder, twisted me round, beamed excitedly, and pointed ahead and below. His lips were moving, but whatever he said was inaudible above the roar of the motors.

I followed the direction indicated by his outstretched fore-finger; and, barely visible through the mist, it showed me two tiny specks of—land. This happened at 8:15 A. M. on June 15th.

With a light heart, I put away charts and tables of calculation, and disregarded the compass needle. My work as navigator of the flight was at an end.

Alcock flew straight for the specks of land, which revealed themselves as two tiny islands—Ecshal and Turbot, as we afterwards discovered. In his log of the return flight, from New York to Norfolk, of the British airshipR-34, Brigadier-General Maitland, C. M. G., D. S. O., notes the curious coincidence that his first sight of land was when these same two islands appeared on the starboard bow of the dirigible.

From above the islands the mainland was visible, and we steered for the nearest point on it. The machine was still just underneath the clouds, and flying at two hundred and fifty feet; from which low height I saw plainly the white breakers foaming on to the shore. We crossed the coast of Ireland at 8:25 A. M.

I was then uncertain of our exact location, and suggested to Alcock that the best planwould be to find a railway line and follow it south. A few minutes later, however, the wireless masts at Clifden gave the key to our position. To attract attention, I fired two red flares from the Very pistol; but as they seemed to be unnoticed from the ground, we circled over the village of Clifden, about two miles from the wireless station.

Although slightly off our course when we reached the coast, we were in the direct line of flight for Galway, at which place I had calculated to hit Ireland. Not far ahead we could see a cluster of hills, with their tops lost in low-lying clouds.

Here and elsewhere the danger of running into high ground hidden from sight by the mist would have been great, had we continued to fly across Ireland. Alcock, therefore, decided to land.

If the atmosphere had been clearer, we could easily have reached London before touching earth, for the tanks of the Vickers-Vimy still contained enough gasoline to keep the machine in the air for ten hours longer. Thus, had we lost our way over the ocean, there would have been a useful margin of time for cruising about in search of ships.

Having made up our minds to land at once, we searched below for a smooth stretch of ground. The most likely looking place in the neighborhood of Clifden was a field near the wireless station. With engines shut off, we glided towards it, heading into the wind.

Alcock flattened out at exactly the right moment. The machine sank gently, the wheels touched earth and began to run smoothly over the surface. Already I was indulging in the comforting reflection that the anxious flight had ended with a perfect landing. Then, so softly as not to be noticed at first, the front of the Vickers-Vimy tilted inexplicably, while the tail rose. Suddenly the craft stopped with an unpleasant squelch, tipped forward, shook itself, and remained poised on a slant, with its fore-end buried in the ground, as if trying to stand on its head.

I reached out a hand and arm just in time to save a nasty bump when the shock threw me forward. As it was, I only stopped a jarring collision with the help of my nose. Alcock had braced himself against the rudder control bar. The pressure he exerted against it to save himself from falling actually bent the straight bar,which was of hollow steel, almost into the shape of a horse-shoe.

Deceived by its smooth appearance, we had landed on top of a bog; which misfortune made the first non-stop transatlantic flight finish in a crash. It was pitiful to see the distorted shape of the aëroplane that had brought us from America, as it sprawled in ungainly manner over the sucking surface. The machine's nose and its lower wings were deep in the bog. The empty cockpit in front, used in a Vickers-Vimy bomber by the observer, was badly bent; but, being of steel, it did not collapse. Quite possibly we owe our lives to this fact. In passing, and while gripping firmly my wooden penholder (for the year is not yet over), I consider it extraordinary that no lives have been lost in the transatlantic flights of 1919.

The leading edge of the lower plane was bent in some places and smashed in others, the gasoline connections had snapped, and four of the propeller blades were buried in the ground, although none were broken. That about completed the record of preliminary damage.

We had landed at 8:40 A. M., after being in the air for sixteen hours and twenty-eight minutes. The flight from coast to coast, on astraight course of one thousand six hundred and eighty nautical miles, lasted only fifteen hours and fifty-seven minutes, our average speed being one hundred and five to one hundred and six knots. For this relatively rapid performance, a strong following wind was largely responsible.

As a result of the burst connections from tank to carburetor, gasoline began to swill into the rear cockpit while we were still inside it. Very fortunately the liquid did not ignite. Alcock had taken care to switch off the current on the magnetos, as soon as he realized that a crash was imminent, so that the sparks should have no chance of starting a fire.

We scrambled out as best we could, and lost no time in salving the mailbag and our instruments. The gasoline rose rapidly, and it was impossible to withdraw my chart and the Baker navigating machine before they had been damaged.

I then fired two white Very flares, as a signal for help. Almost immediately a small party, composed of officers and men belonging to the military detachment at Clifden, approached from the wireless station.

"Anybody hurt?"—the usual inquiry whenan aëroplane is crashed—was the first remark when they arrived within shouting distance.

"No."

"Where you from?"—this when they had helped us to clear the cockpit.

"America."

Somebody laughed politely, as if in answer to an attempt at facetiousness that did not amount to much, but that ought to be taken notice of, anyhow, for the sake of courtesy. Quite evidently nobody received the statement seriously at first. Even a mention of our names meant nothing to them, and they remained unconvinced until Alcock showed them the mail-bag from St. John's. Then they relieved their surprised feelings by spontaneous cheers and painful hand-shakes, and led us to the officers' mess for congratulations and hospitality.

Burdened as we were with flying kit and heavy boots, the walk over the bog was a dragging discomfort. In addition, I suddenly discovered an intense sleepiness, and could easily have let myself lose consciousness while standing upright.

Arrived at the station, our first act was to send telegrams to the firm of Messrs. Vickers,Ltd., which built the Vickers-Vimy, to the LondonDaily Mail, which promoted the transatlantic competition, and to the Royal Aëro Club, which controlled it.

My memories of that day are dim and incomplete. I felt a keen sense of relief at being on land again; but this was coupled with a certain amount of dragging reaction from the tense mental concentration during the flight, so that my mind sagged. I was very sleepy, but not physically tired.

We lurched as we walked, owing to the stiffness that resulted from our having sat in the tiny cockpit for seventeen hours. Alcock, who during the whole period had kept his feet on the rudder bar and one hand on the control lever, would not confess to anything worse than a desire to stand up for the rest of his life—or at least until he could sit down painlessly. My hands were very unsteady. My mind was quite clear on matters pertaining to the flight, but hazy on extraneous subjects. After having listened so long to the loud-voiced hum of the Rolls-Royce motors, made louder than ever by the broken exhaust pipe on the starboard side, we were both very deaf, and our ears would not stop ringing.

Later in the day we motored to Galway witha representative of the LondonDaily Mail. It was a strange but very welcome change to see solid objects flashing past us, instead of miles upon monotonous miles of drifting, cloudy vapor.

Several times during that drive I lost the thread of connection with tangible surroundings, and lived again in near retrospect the fantastic happenings of the day, night and morning that had just passed. Subconsciously I still missed the rhythmic, relentless drone of the Rolls-Royce aëro-engines. My eyes had not yet become accustomed to the absence of clouds around and below, and my mind felt somehow lost, now that it was no longer preoccupied with heavenly bodies, horizon, time, direction, charts, drift, tables of calculations, sextant, spirit level, compass, aneroid, altimeter, wireless receiver and the unexpected.

For a while, in fact, the immediate past seemed more prominent than the immediate present. Lassitude of mind, coupled with reaction from the long strain of tense and unbroken concentration on one supreme objective, made me lose my grip of normal continuity, so that I answered questions mechanically andwanted to avoid the effort of talk. The outstanding events and impressions of the flight—for example the long spin from four thousand to fifty feet, and the sudden sight of the white-capped ocean at the end of it—passed and repassed across my consciousness. I do not know whether Alcock underwent the same mental processes, but he remained very silent. Above all I felt the need of reëstablishing normal balance by means of sleep.

The wayside gatherings seemed especially unreal—almost as if they had been scenes on the film. By some extraordinary method of news transmission the report of our arrival had spread all over the district, and in many districts between Clifden and Galway curious crowds had gathered. Near Galway we were stopped by another automobile, in which was Major Mays of the Royal Aëro Club, whose duty it was to examine the seals on the Vickers-Vimy, thus making sure that we had not landed in Ireland in a machine other than that in which we left Newfoundland. A reception had been prepared at Galway; but our hosts, realizing how tired we must be, considerately made it a short and informal affair. Afterwards we slept—for the first time in over forty hours.

Alcock and I awoke to find ourselves in a wonderland of seeming unreality—the product of violent change from utter isolation during the long flight to unexpected contact with crowds of people interested in us.

To begin with, getting up in the morning, after a satisfactory sleep of nine hours, was strange. In our eastward flight of two thousand miles we had overtaken time, in less than the period between one sunset and another, to the extent of three and a half hours. Our physical systems having accustomed themselves to habits regulated by the clocks of Newfoundland, we were reluctant to rise at 7 A. M.; for subconsciousness suggested that it was but 3:30 A. M.

Transatlantic machine© Underwood & Underwood, N. Y.THE VICKERS-VIMY TRANSATLANTIC MACHINE IN THE AIR

The last meal in AmericaTHE LAST SQUARE MEAL IN AMERICA WAS EATEN NEAR THE WINGS OF THE MACHINE

THE LAST SQUARE MEAL IN AMERICA WAS EATEN NEAR THE WINGS OF THE MACHINE

This difficulty of adjustment to the sudden change in time lasted for several days. Probably it will be experienced by all passengers traveling on the rapid trans-ocean air servicesof the future—those who complete a westward journey becoming early risers without effort, those who land after an eastward flight becoming unconsciously lazy in the mornings, until the jolting effect of the dislocation wears off, and habit has accustomed itself to the new conditions.

Then, after breakfast—eaten in an atmosphere of the deepest content—there began a succession of congratulatory ovations. For these we were totally unprepared; and with our relaxed minds, we could not easily adapt ourselves to the conditions attendant upon being magnets of the world's attentive curiosity.

First came a reception from the town of Galway, involving many addresses and the presentation of a memento in the form of a Claddagh ring, which had historical connections with a landing on the coast of Ireland thereabouts by vessels of the Spanish Armada.

The warm-hearted crowd that we found waiting at Galway Station both amazed and daunted us. We were grateful for their loud appreciation, but scarcely able to respond to it adequately. Flowers were offered, and we met the vanguard of the autograph hunters. We musthave signed our names hundreds of times during the journey to Dublin—on books, cards, old envelopes and scraps of paper of every shape and every state of cleanliness. This we did wonderingly, not yet understanding why so many people should ask for our signatures, when three days earlier few people had heard of our names.

The men, women and children that thronged every station on the way to Dublin seemed to place a far higher value on our success than we did ourselves. Until now, perhaps, we had been too self-centered to realize that other people might be particularly interested in a flight from America to England. We had finished the job we wanted to do, and could not comprehend why it should lead to fuss.

Now, however, I know that the crowds saw more clearly than I did, and that their cheers were not for us personally, but for what they regarded as a manifestation of the spirit of adventure, the True Romance—call it what you will. For the moment this elusive ideal was suggested to them by the first non-stop journey by air across the Atlantic, which we had been fortunate enough to make.

At one station, where a military band played our train in and out again, a wooden model ofan aëroplane was presented to Alcock by a schoolboy. At Dublin, reached on the morning of Trinity Sunday, Alcock and I passed with difficulty through the welcoming crowds, and drove towards the Automobile Club in separate cars. In due course, I reached sanctuary; but where was Alcock? We waited and waited, and finally sent out scouts to search for him. They came back with the news that he had been kidnapped, and taken to Commons in Trinity College.

Landing at Holyhead next morning, we were welcomed back to the shores of England by Mr. R. K. Pierson, designer of our Vickers-Vimy machine, by Captain Vickers, of the famous firm that built it, and by Mr. C. Johnson, of the Rolls-Royce Company that supplied our motors. Scenes all along the line to London were a magnified repetition of those from Galway to Dublin. Chester, Crewe, Rugby and other towns each sent its Mayor or another representative to the station. Aëroplanes escorted the train all the way to London. Again we could only play our part in a more or less dazed state of grateful wonder.

Of the warm-hearted welcome of the people of London, I have confused recollectionsthat include more receptions, more and larger crowds, more stormy greetings, and an exciting, pleasant drive to the Royal Aëro Club. Alcock delivered to the postal authorities the mail-bag from St. John's, with regrets that it had not been possible to fly direct to London with the letters. In the evening we separated, Alcock to see a big prize fight, I to visit my fiancée.

Perhaps the welcome that we appreciated most was that given us next day when, at the Weybridge works of the Vickers Company, we were cheered and cheered by the men and girls who had built our transatlantic craft. We were glad indeed to be able to tell them and the designer of the machine that their handiwork had stood a difficult test magnificently, as had the Rolls-Royce engines. One of my most sincere reasons for satisfaction was that the late Mr. Albert Vickers, one of the founders of the great firm, regarded the flights as having maintained the Vickers tradition of efficiency, originality and good workmanship.

That Lieutenant-Commander Read, U.S.N., who commanded the American flying boatN. C. 4in its flight from America to England, had left London before our arrival was a causeof real regret. Both Alcock and I were anxious to meet him and his crew, so that we might compare our respective experiences of aërial navigation and of weather conditions over the Atlantic. The United States aviators who flew to Europe, and those that were so unlucky in coming to grief at the Azores, showed themselves to be real sportsmen; and without any exception, there was the best possible feeling between them and all the British aviators who made, or attempted to make, a non-stop journey from Newfoundland to Ireland.

Although I am supremely glad to have had the opportunity of flying the Atlantic by aëroplane, afterthoughts on the risks and chances taken have convinced me that, while our own effort may have been useful as a pioneer demonstration, single or twin engine aircraft are altogether unsuitable for trans-ocean voyages. We were successful—yes. But a temporary failure of either of our motors (although this is unlikely when dealing with Rolls-Royce or other first-class aëro motors) would have meant certain disaster and likely death.

Another vital drawback of the smaller machines is that so much space, and so much disposablelift, is needed for fuel that the number of persons on board must be limited to two, or in some cases three, and no freight can be taken. Yet another is that should the navigator of an aëroplane make an important error in calculation while flying over the ocean in fog or mist, an enforced descent into the water, after the limited quantity of fuel has been expended over a wrong course, is more than possible.

In the present condition of practical aëronautics, the only heavier-than-air craft likely to be suitable for flying the Atlantic are the large flying boats now being built by various aircraft companies; and even they are limited as to size by certain definite formulæ. The development in the near future of long flights over the ocean would seem, therefore, to be confined to lighter-than-air craft.

In this connection the two voyages across the Atlantic of the British government airship R-34, not long after Alcock and I had returned to London, was a big step towards the age of regular air service between Britain and America. With five motors theR-34could carry on if one, or even two of them were out of action. In fact, on its return flight, one motor broke down beyond the possibility of immediate repair; although there were ample facilities and an amplecrew for effecting immediate repairs in the air. Yet she completed her journey without difficulty. With a disposable lift of twenty-nine tons, the airship carried plenty of fuel for all contingencies, an adequate crew, and heavy wireless apparatus that could not have been fitted on the larger aëroplanes.

Despite all this preliminary weight, a large collection of parcels, letters and newspapers were taken from America to England in record time. Had the weather conditions been at all suitable she could easily have brought the mail direct from New York to London by air. All honor to General Maitland, Major Scott and the other men who carried out this astonishing demonstration so early as July, 1919.

Even vessels of theR-34type, however, are quite unsuitable for regular traffic across the Atlantic. Much bigger craft will be needed if the available space and the disposable lift are to be sufficient for the carrying of freight or passengers on a commercial basis. Already the construction of airships two and a half and five times the size of theR-34, with approximate disposable lifts of one hundred and two hundred tons respectively, is projected. Whensuch craft are accomplished facts, and when further progress has been made in solving weather and navigation problems, we may look for transatlantic flights on a commercial basis.

I do not claim to be an especial authority on the theory of navigation—indeed, it was as a prisoner of war that I first took up seriously the study of that science. But I believe that sustained and sufficient concentration can give a man what he wants; and on this assumption I decided to learn whatever might be learned about navigation as applied to aircraft. As yet, like most aspects of aëronautics, this is rather indefinite, although research and specially adapted instruments will probably make it as exact as marine navigation.

Navigation is the means whereby the mariner or aviator ascertains his position on the surface of the earth, and determines the exact direction in which he must head his craft in order to reach its destination.

The methods of navigation employed by mariners are the result of centuries of research andinvention, but have not yet reached finality—witness the introduction within the last few years of the Gyroscopic Compass and the Directional Wireless Telegraph Apparatus, as well as of improved methods of calculation.

In short journeys over land by aëroplane or airship the duties of a navigator are light, so long as he can see the ground and check his progress towards the objective by observation and a suitable map.

But for long distance flights, especially over the ocean and under circumstances whereby the ground cannot be seen, the navigator of the air borrows much from the navigator of the sea. He makes modifications and additions, necessitated by the different conditions of keeping to a set course through the atmosphere and of keeping to a set course through the ocean but the principles underlying the two forms of navigation are identical.

It is impossible to explain aërial navigation without seeming to paraphrase other writers on the subject. One of the simplest explanations of the science is that of Lieutenant Commander K. Mackenzie Grieve in "Our Atlantic Attempt," which he wrote in collaboration withMr. Harry Hawker, his pilot, after their glorious attempt to win the LondonDaily Mail'stransatlantic competition.

The chief differences between the navigation of aircraft and the navigation of seacraft are occasioned by:

(a) The vastly greater speed of aircraft, necessitating more frequent observations and quicker methods of calculation.

(b) The serious drift caused by the wind. This may take aircraft anything up to forty or more miles off the course in each hour's flying, according to the direction and strength of the wind. In cloudy weather, or at night, a change in the wind can alter the drift without the knowledge of the navigator. Hence, special precautions must be taken to observe the drift at all possible times.

(c) The absence of need for extreme accuracy of navigation in the air, since a ten or even twenty mile error from the destination in a long journey is permissible. Another favorable point is that rocks, reefs and shoals need not be avoided. This permits the aërial navigator to use short cuts and approximations in calculation, which would be criminal in marine navigation.

There are three methods of aërial navigation—"Dead Reckoning," Astronomical Observation, and Directional Wireless Telegraphy. None should be used alone; for although accuracy may be obtained with any single method, it is highly advisable to check each by means of the others.

As in the case of marine navigation, a reliable compass, either of the magnetic or gyroscopic type, is essential for aërial navigation, as well as an accurate and reliable chronometer. Suitable charts must be provided, showing all parts of the route to be covered. When the magnetic compass is used, such charts should show the variation between True and Magnetic North at different points on the route.

"Dead Reckoning" is the simplest method of navigation; and, under favorable conditions, it gives a high degree of accuracy. A minimum of observation is required, but careful calculation is essential.

The "Dead Reckoning" position of an aëroplane or airship at any time is calculated from its known speed and direction over the surface of the earth or ocean, and its known course asindicated by the magnetic or gyroscopic compass.

To determine the direction of movement of an aëroplane or airship, as apart from the direction in which it is headed, an instrument known as a Drift Indicator, or Drift Bearing Plate, is used.

One form of Drift Indicator consists of a simple dial, with the center cut away and a wire stretched diametrically across it. The outer edge of the dial is divided into degrees, in a similar manner to that of the compass. It is mounted in such a way that an observer can, by looking through the center of the disc, see the ground or ocean below him. The disc is then turned until objects on the ground—or white-caps, icebergs, ships, or other objects visible on the surface of the ocean—are seen to move parallel with the wire, without in any way deviating from it. The angle which the wire then makes with the direction in which the nose of the aëroplane or airship is pointing gives the angle of drift.

The ground speed (or speed over the surface of the earth) of aircraft can be measured by observing the time taken in passing over any fixed or very slowly moving object, while a certainangular distance is described—this being found by suitable sights, attached to the Drift Bearing Plate. From the result, considered in conjunction with the height of the aëroplane or airship, the actual speed over the surface is calculated. This speed will be in the direction shown by the wire of the Drift Bearing Plate.

The ground speed so found will differ nearly always from the air speed, as shown by the air speed meter, because of the effect of the wind. The difference is greater or less according to the wind's relation to the direction in which the aëroplane or airship is headed.

Having found by observation the drift, the ground speed and the air speed, a simple instrument such as the Appleyard Course and Distance Calculator then permits the aërial navigator to discover without difficulty, as on a slide rule, the strength and direction of the wind. Should the actual track of aircraft over the earth's surface not coincide with the desired course, the Course and Distance Calculator, or a similar instrument, can thus be used to calculate, in connection with the wind velocity and direction already found, the direction in which the nose of the craft must be pointed in order to correct the deviation due to drift.

Sir John AlcockTHE LATE CAPT. SIR JOHN ALCOCK JUST BEFORE STARTING

THE LATE CAPT. SIR JOHN ALCOCK JUST BEFORE STARTING

The first ail mailSHIPPING THE FIRST DIRECT TRANSATLANTIC AIR MAIL

SHIPPING THE FIRST DIRECT TRANSATLANTIC AIR MAIL

Knowing the latitude and longitude of the point of departure, and noting carefully the time that elapses between each separate observation of the ground speed and of the course, the air navigator, with the aid of a specially prepared set of "traverse tables" (as used by mariners), can easily plot on his chart the distance covered and the direction in which it has been covered. Hence the position of the aircraft at any time is either known definitely, or can be forecast with a fair degree of accuracy.

For aërial navigation by means of "Dead Reckoning," frequent observations of ground speed and drift are necessary. If aircraft are cut off by clouds or fog from all possibility of sighting the surface of the earth, grave errors may occur, since in long distance flights the wind's velocity and direction often change without the pilot's knowledge.

In navigation by astronomical observation, the position of the aëroplane or airship is found by observing the height above the horizon of either the sun or another heavenly body, such as a star that is easy of recognition. Themethod depends upon the known fact that at any given instant the sun is vertically above some definite point on the earth's surface. This point can be calculated from the time of the observation and the declination and equation of time, as tabulated in the nautical almanac.

In the case of stars, the right ascension of the sun and of the star also enter into the calculation. The method of carrying out such calculations is too involved for the scope of this volume, and the reader is referred to many of the excellent text books published on the subject of navigation.

Since the navigator knows, from the time of his observation, the point on the earth's surface over which is the heavenly body in question, it is clear that around this point circles on the surface of the earth may be described. From any point in any one circle the heavenly body will appear to have the same altitude or elevation above the horizon. A single observation of the altitude of any one heavenly body shows, therefore, only that the observer may be at any point on such a circle of equal altitude—otherwise known as a Sumner circle. But it does not fix that point.

A second simultaneous observation, of a different heavenly body, will give a different circle, corresponding to the position of the second body. The intersection of these two circles determines the point of observation.

This fact constitutes a reliable basis for fixing one's position during a clear night, when many stars are visible and choice of suitable heavenly bodies may be made. During the day, however, the light of the sun prevents other heavenly bodies from being seen, so that only a single observation is possible.

If the aëroplane or airship were not moving, then two successive observations of the sun, with an interval of an hour or more between them, would give the intersecting circles and fix the position. But the aircraft being in motion, it is necessary to combine the method of "Dead Reckoning" with the use of the Sumner circles, as found by observation of the sun's altitude.

In order to avoid drawing the entire circle, a small portion only of it is shown on the chart—so small that it may be regarded as a straight line. Such a small section of the Sumner circle is known as a "position line."

The desired track is laid out on the chart, and the "Dead Reckoning" position for thetime of the solar observation is indicated on it. The track should be intersected at this point by the position line, the observation thus forming a check upon the "Dead Reckoning."

The altitude of the sun or of a star is measured by the sextant. For such an observation to be exact, it is necessary that not only should the sun or stars be viewed clearly, but that a clear horizon, formed either by the ocean or by suitable clouds, should be visible.

Corrections must be applied to the observed altitude for the aircraft's height above the horizon, for refraction, and for the diameter of the body under observation—the latter two corrections being given in the nautical almanac. There may be, also, an error inherent in the sextant itself. For extremely refined navigation, corrections are applied in accordance with the direction and velocity of the aëroplane or airship; but these are not really necessary, since navigation of aircraft does not require such close calculation.

When the sun or star observed is directly south of the aërial navigator in the northern hemisphere, or north of him in the southern hemisphere, the altitude, corrected for declination of the body under observation, gives theaircraft's latitude. When the navigator is directly east or west, the altitude, corrected for the time of observation, gives its longitude.

If the horizon is invisible, owing to fogs or unsuitable clouds, it may be replaced by means of a spirit level; but great care should be taken in making such observations, since a spirit level on an aëroplane or airship is not wholly reliable, unless the craft is proceeding in an absolutely straight direction, and without sway of any kind.

All methods of navigation by Astronomical Observation fail when the sky is obscured by clouds and the heavenly bodies cannot be seen. As a general rule this drawback does not hamper air navigation to any great extent, since aircraft should be able to climb above most of the obscuring clouds. Yet it may happen, as it did in the case of our transatlantic flight, that the clouds are too high for such a maneuver.

If it were possible to measure accurately the true bearing of the sun or star at the moment of observation, then a single observation of a single heavenly body would fix the position of the craft at the intersection of the line of bearing with the position line. At the time of writing, however, there are no satisfactory meansof making such a measurement with the required degree of accuracy. Apparatus which will enable this to be done is now in course of development. Navigation by means of astronomical observation will thereby be simplified greatly.

With the great improvements that have been made in the year 1919, the guiding of aircraft by directional wireless telegraphy is rapidly becoming a reliable and accurate means of aërial navigation. Although complicated in design and construction, the complete receiving equipment for aircraft is now light, compact, and simple of operation.

Coffee on boardHOT COFFEE WAS TAKEN ABOARD

HOT COFFEE WAS TAKEN ABOARD

StartSLOW RISING NEARLY CAUSED DISASTER AT THE START OF THE GREAT FLIGHT

SLOW RISING NEARLY CAUSED DISASTER AT THE START OF THE GREAT FLIGHT

The receiving equipment on aëroplanes and airships is arranged so as to indicate, with a comparatively high degree of accuracy, the direction from which wireless signals are received. The position of the sending, or beacon, station being known, the bearing of the aircraft from that station may be plotted on a suitable chart, in which small segments of great circles are represented by straight lines. Simultaneous bearings on two known beacon stations aresufficient to fix the observer's position with tolerable accuracy at the intersection of the lines of bearing, provided that they intersect at a reasonable angle—45 degrees or more, where possible.

With the very close tuning rendered possible by the use of continuous waves, beacon stations of the future will probably be provided with automatic means whereby directional signals can be sent out at intervals of one hour or less. Such signals will be coded, so that the crews of aircraft can identify the wireless station. The wave lengths must be chosen so as not to interfere with messages sent from commercial stations.

If there be a beacon station at the air navigator's destination, it is possible for him to direct his course so that the craft is always headed for the beacon; and in due time he will reach his objective.

This simple but lazy method, however, is not to be recommended; for, owing to the action of the wind, the route covered is longer than the straight course. To counteract drift and proceed in a direct line towards his destination, the air navigator frequently has to direct his course so that the craft is not headed straightfor the objective. Hence, with a single beacon station, frequent observations of drift are necessary, if the shortest route is to be followed. Thus:

Path: headed towards beacon stationApproximate path taken by aircraft headed always towards beacon station.

Approximate path taken by aircraft headed always towards beacon station.

Path: headed to counteract driftPath taken by aircraft headed so as to counteract drift.

Path taken by aircraft headed so as to counteract drift.

When two or more beacon stations are available, and positions can be ascertained at least once an hour, observation on the surface of the ocean for drift, although desirable, is not absolutely necessary. The drift may be calculated with accuracy enough from the craft's position as found by the lines of bearing indicated in messages from the various beacon stations.

Another method of employing the WirelessDirection Finder is for aircraft to send out signals to two or more beacon stations, which reply by advising the air navigator of his bearing in relation to themselves. This is, perhaps, the most accurate method. Its disadvantage lies in the fact that whereas the heavier and more robust apparatus needed for it can easily be employed in the stationary beacon stations, few aircraft will be able to support wireless sending apparatus of sufficient weight to carry over the long distances they must cover in trans-oceanic aërial travel.

The greatest advantage of air navigation by means of wireless telegraphy is that it can be employed in any weather. Fogs and clouds do not make it inoperative, nor even less accurate. Another recommendation is that its use does not entail a knowledge of advanced mathematics, as required for navigation by astronomical observation.

I believe firmly that the air navigator of the future will rely upon the Wireless Direction Finder as his mainstay, while using astronomical observation and the system of "Dead Reckoning" as checks upon the wireless bearings given him, and as second and third strings to his bow, in case the wireless receiving apparatus breaks down.

Although three pioneer flights were made across the Atlantic during the summer of 1919, the year passed without bringing to light any immediate prospect of an air service between Europe and America. Nor does 1920 seem likely to produce such a development on a regular basis.

Before a transatlantic airway is possible, much remains to be done—organization, capitalization, government support, the charting of air currents, the establishment of directional wireless stations, research after improvements in the available material. All this requires the spending of money; and for the moment neither governments nor private interests are enamored of investments with a large element of speculation.

But, sooner or later, a London-New Yorkservice of aircraft must be established. Its advantages are too tremendous to be ignored for long. Prediction is ever dangerous; and, meantime, I am confining myself to a discussion of what can be done with the means and the knowledge already at the disposal of experts, provided their brains are allied to sufficient capital.

Notwithstanding that the first two flights across the Atlantic were made respectively by a flying-boat and an aëroplane, it is very evident that the future of transatlantic flight belongs to the airship. That the apparatus in which Sir John Alcock and I made the first non-stop air journey over the Atlantic was an aëroplane only emphasizes my belief that for long flights above the ocean the dirigible is the only useful vehicle. If science discovers some startlingly new motive power—for example, intermolecular energy—that will revolutionize mechanical propulsion, heavier-than-air craft may be as valuable for long flights as for air traffic over shorter distances. Until then trans-ocean flying on a commercial basis must be monopolized by lighter-than-air craft.

The aëroplane—and in this general term I include the flying boat and the seaplane—is impracticableas a means of transport for distances over one thousand miles, because it has definite and scientific limitations of size, and consequently of lift. The ratio of weight to power would prevent a forty-ton aëroplane—which is approximately the largest heavier-than-air craft that at present might be constructed and effectively handled—from remaining aloft in still air for longer than twenty-five hours, carrying a load of passengers and mails of about five tons at an air speed of, say, eighty-five miles an hour. Its maximum air distance, without landing to replenish the fuel supply, would thus be two thousand, one hundred and twenty-five miles. For a flight of twenty-five hundred miles all the disposable lift (gross lift minus weight of structure) would be needed for crew and fuel, and neither passengers nor freight could be taken aboard.

There is not in existence an aëroplane capable of flying, without alighting on the way, the three thousand miles between London and New York, even when loaded only with the necessary crew. With the very smallest margin of safety no transatlantic route of over two thousand miles is admissible for aëroplanes. This limitation would necessitate time-losing andwearisome journeys between London and Ireland, Newfoundland and New York, to and from the nearest points on either side of the ocean. Even under these conditions only important mail or valuable articles of little weight might be carried profitably.

As against these drawbacks, the larger types of airships have a radius far wider than the Atlantic. Their only limit of size is concerned with landing grounds and sheds; for the percentage of useful lift increases with the bulk of the vessel, while the weight to power ratio decreases. A voyage by dirigible can therefore be made directly from London to New York, and far beyond it, without a halt.

Another advantage of lighter-than-air craft is that whereas the restricted space on board an aëroplane leaves little for comfort and convenience, a large rigid airship can easily provide first-rate living, sleeping and dining quarters, besides room for the passengers to take exercise by walking along the length of the inside keel, or on the shelter deck. In a saloon at the top of the vessel no noise from the engines would be heard, as must be the case in whatever quarters could be provided on a passenger aëroplane.

Yet another point in favor of the airship as a medium for trans-ocean flight is its greater safety. An aëroplane is entirely dependent for sustentation in the air on the proper working of all its motors. Should two motors—in some cases even one—break down, the result would be a forced descent into the water, with the possibility of total loss on a rough sea, even though the craft be a solid flying boat. In the case of an airship the only result of the failure of any of the motors is reduction of speed. Moreover, a speed of four-fifths of the maximum can still be maintained with half the motors of an airship out of action, so that there is no possibility of a forced descent owing to engine breakdown. The sole result of such a mishap would be to delay the vessel's arrival. Further, it may be noted that an airship's machinery can be so arranged as to be readily accessible for repairs and replacement while on a voyage.

As regards comparative speed the heavy type of aëroplane necessary to carry an economical load for long distances would not be capable of much more than eighty-five to ninety miles an hour. The difference between this and thepresent airship speed of sixty miles an hour would be reduced by the fact that an aëroplane must land at intermediate stations for fuel replenishment. Any slight advantage in speed that such heavier-than-air craft possess will disappear with the future production of larger types of dirigible, capable of cruising speeds varying from seventy-five to ninety miles an hour. For the airship service London-New York direct, the approximate time under normal conditions should be fifty hours. For the aëroplane service London-Ireland-Newfoundland-New York the time would be at least forty-six hours.

Perhaps the most convincing argument in favor of airships as against aëroplanes for trans-ocean aviation is that of comparative cost. All air estimates under present conditions must be very approximate; but I put faith in the carefully prepared calculations of experts of my acquaintance. These go to show that, with the equipment likely to be available during the next few years, a regular and effective air service between London and New York will need (again emphasizing the factor of approximation) the following capital and rates:

These figures for an airship service are based on detailed calculations, of which the more important are:

The weight available for passengers and mails on each airship of the type projected would be fifteen tons. This permits the carrying of one hundred and forty passengers and effects, or ten tons of mails and fifty passengers. To cover the working costs and interest, passengers would have to be charged $240 per head and mails $2,025 per ton for the voyage London-New York.

This charge for passengers is already lessthan that for the more expensive berths on transatlantic liners. Without a doubt, with the coming of cheaper fuel, lower insurance rates and larger airships, it will be reduced eventually to the cheapest rate for first-class passages on sea liners.

With a fleet of four airships, a service of two trips each way per week is easily possible. For aëroplanes with a total load of forty tons the weight available for passengers and mails is 2.1 tons. If such a craft were to carry the same weekly load as the service of airships—thirty tons each way—it would be necessary to have fourteen machines continually in commission. Allowing for one hundred per cent. spare craft as standby for repairs and overhaul, twenty-eight aëroplanes would be required. The approximate cost of such a service is:

It will be seen from the above that the direct running cost is 38%, and the overhead charges 62% of the total cost.

With a weight of 2.1 tons available on each machine for passengers and mails twenty passengers might be carried. To cover the working costs and interest they must be charged $575 per head. The rate for mails would be $5,500 per ton.

Having made clear that the airship is the only means of transatlantic flight on a paying basis, the next point to be considered is the type of dirigible necessary. A discussion at present of the size of the airships that will link Europe and America can be little more substantial than guesswork. The British dirigibleR-34, which last year made the famous pioneer voyage between England and the United States, is toosmall for commercial purposes, with its disposable lift of twenty-nine tons and its gas capacity of less than two million cubic feet. Experts have predicted the use of airships of five million and ten million cubic feet capacity, with respective weights of thirty tons and one hundred tons available for passengers and freight.

It is probable, however, that such colossi must await birth for many years, and that a beginning will be made with moderate-sized craft of about three million, five hundred thousand cubic feet capacity, similar to those that serve as the basis of the estimates for a service between London and New York. A combination of British interests is planning to send ships of this type all over the world. These can be built immediately, and there are already in existence suitable sheds to house them. Details of their structure and capabilities may be of interest.

Back to Index Next