Chapter 10 No.10

The Future of Transatlantic Flight

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 York service 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 a?roplane, 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 a?roplane 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 a?roplane-and in this general term I include the flying boat and the seaplane-is impracticable as 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 a?roplane-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 a?roplane 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 a?roplanes. This limitation would necessitate time-losing and wearisome 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 a?roplane 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 a?roplane.

Yet another point in favor of the airship as a medium for trans-ocean flight is its greater safety. An a?roplane 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 a?roplane 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 the present airship speed of sixty miles an hour would be reduced by the fact that an a?roplane 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 a?roplane 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 a?roplanes 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:

Airship

Service[1] A?roplane

Service[2]

Capital required $13,000,000 $19,300,000

Passenger rate:

London-New York $240 $575

Rate per passenger:

8 cents 18 cents

Mails per ounce:

London-New York 6-1/4 cents 15-1/2 cents

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

Capital Charges:

Four airships of 3,500,000 cu. ft. capacity, at $2,000,000 each $8,000,000

Two double airship sheds at $1,500,000 each $150,000 each 3,000,000

Land for two sheds and a?rodromes at 300,000

Workshops, gas plants, and equipment 750,000

Working capital, including spare parts, stores, etc. 850,000

Wireless equipment 50,000

Miscellaneous accessories 50,000

Total capital required $13,000,000

Annual charge, interest at 10% $1,300,000

Depreciation and Insurance:

Airships.

Useful life, about 3 years.

Obsolete value, about $100,000 per ship.

Total depreciation per ship, $1,900,000 in three years.

Average total depreciation per annum for four ships for 3 years, $2,535,000.

Airship sheds.

Total annual charge $90,000

Workshops and plant.

Depreciation at 5% per annum 17,500

Total annual charge for depreciation 2,650,000

Total annual insurance charges on airships and plant 617,500

Annual Establishment Expenses:

Salaries of Officers and Crews-

4 airship commanders $20,000

8 airship officers 30,000

Total number crew hands (64) 80,000 $130,000

$130,000

Salaries of Establishment-

Management and Staff $25,000

Workshop hands, storekeepers, etc. (50 at each shed-total 100) 100,000 $125,000

Total annual establishment expenses $255,000

Repairs and Maintenance:

Sheds and plant, annual charge, say, $25,000

Repairs and overhaul of airships 100,000

Total charge $125,000

Total annual charges on above basis $4,947,500

Say $5,000,000

Cost Chargeable per Crossing:

Taking the total number of crossings per year as 200 (London-New York)-

Proportion of annual charges per crossing $25,000

Petrol per trip, 30 tons at $125 per ton. 3,750

Oil per trip, 2 tons at $200 per ton. 400

Hydrogen used, 750,000 cu. ft. at $2.50 per 1,000 cu. ft. 1,875

Cost of food per trip for crew of 19 and 100 passengers 2,000

Total charge per crossing (London-New York) $33,025

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 less than 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 a?roplanes 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 a?roplanes would be required. The approximate cost of such a service is:

Capital Charges:

28 a?roplanes at $600,000 $16,750,000

28 a?roplane sheds at $50,000 1,400,000

Land for 4 a?rodromes 500,000

Workshops and equipments 100,000

Spare parts, etc. 500,000

Wireless equipment 50,000

Total capital required $19,300,000

Annual charge at 10% interest $1,930,000

Depreciation and Insurance:

A?roplanes.

Useful life, say 3 years, as for airships.

Obsolete value, say, $30,000 per machine. Average total depreciation per annum for 28 machines $5,250,000

A?roplane Sheds.

Total annual charge 60,000

Workshops and Plant.

Depreciation at 3% per annum 3,000

Total annual charge for depreciation 5,314,000

Total annual insurance charges on machinery and plant 1,152,000

Annual Establishment Expenses:

Salaries of 36 pilots at $3,000 per annum $108,000

Salaries of 36 engineers at $2,000 per annum 72,000

Salaries of 12 stewards at $1,500 per annum 18,000

Salaries of establishment-

Management and staff 25,000

Workshop hands and storekeepers, etc., 100 off 100,000

Total annual establishment expenses $323,000

Repairs and Maintenance:

Sheds and plant, annual charge, say $25,000

Repairs and overhaul to machines 50,000

Total. $75,000

Total annual charges on above basis $8,792,500

Cost chargeable per crossing:

Proportion of annual charges per crossing $7,250

Petrol used per trip, 28 tons at $125 per ton 3,500

Oil per trip, 2 tons at $200 per ton 400

Cost of food per trip for 29 passengers and crew of seven 500

$11,650

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 dirigible R-34, which last year made the famous pioneer voyage between England and the United States, is too small 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.

LUCKY JIM AND TWINKLETOE, THE MASCOTS

THE TRANSATLANTIC FLIGHT ENDED WITH A CRASH IN AN IRISH BOG

The projected airship of three million, five hundred thousand cubic feet capacity is capable of carrying a useful load of fifteen tons (passengers and mails) for a distance of forty-eight hundred miles in eighty hours, at the normal cruising speed. The total lifting power is one hundred and five tons, and the disposable lift (available for fuel, oil, stores, crew, passengers and freight) is sixty-eight tons. The maximum engine power is thirty-five hundred h. p., the maximum speed seventy-five miles an hour. The normal flying speed, using a cruising power of two thousand h. p., is sixty miles an hour. The overall length is eight hundred feet, the maximum diameter and width one hundred feet, and the overall height one hundred and five feet. These particulars and performances are based on present design, and on the results attained with ships of two million cubic feet capacity, now in service. The figures are conservative, and it is probable that a disposable lift greater than that of the specifications will be obtained as a result of improved structural efficiency.

The passenger accommodation will be such that the air journey can be made in comfort equal to that on a first-class liner of the sea. Apart from their comparatively small disposable lift, a main objection to vessels of the R-34 type for commercial purposes is that the living quarters are in cars slung from under the middle envelope. In this position they are necessarily rather cramped. In the proposed craft of three million, five hundred thousand cubic feet capacity the passengers' quarters are at the top of the vessel. There, they will be roomy and entirely free from the vibration of the engines. They are reached through an internal corridor across the length of the ship, or by elevator, from the bottom of it.

The main room is a large saloon lounge fitted with tables and chairs in the style of a Pullman car. Around it are windows, allowing for daylight and for an outlook in every direction. Part of it is fire-proofed, and serves as a smoking room.

Next to, and communicating with, the lounge is the dining saloon. This leads to a serving hatch and electrical cooking apparatus. Electrical power is provided by dynamos driven off the main engines. Current for electric lighting and heating of the saloons, cars and sleeping quarters is provided by the same method.

Sleeping accommodation is in four-berth and two-berth cabins on top of the airship and forward of the living saloons. The cabins are of the type and size fitted on ocean-going steamers. With them are the usual bathrooms and offices. Other conveniences are an open shelter deck at the vessel's aft end, to enable passengers to take the air, and an observation car, fitted below the hull and also at the aft end, so that they can observe the land or sea directly below them.

No danger from fire need be feared. The machinery installation is carefully insulated from the gas bags, and the quarters are to be rendered fire-proof and gas-proof. Moreover, the amount of weight involved by the passengers' section is so small, compared with the weight of the machinery, fuel, cargo and stores, carried in the lower part of the craft, that the stability of the ship for rolling is unaffected by the novel position of the living quarters.

The ship's officers will have on the hull, towards the forward end, a control and navigation compartment, containing the main controls, navigation instruments, charts, and a cabin for the wireless telegraphy installation. The windows of this car give a clear view in every direction.

Other general specifications are:

Hull Structure.-The shape of the hull is of the most perfect stream-line form within the limitations of constructional requirements. An internal keel corridor, running along the bottom of the hull, contains all petrol and oil tanks and the water ballast.

Outer Covering.-The outer cover is made of special weather-proof fabric, which gives the longest possible life. This fabric is as efficient as possible in insulating the gas from change of temperature, and thus avoids great variations in the lift.

Gasbags.-The gas capacity is divided up into gasbags made of suitable rubber-proofed cotton fabric, lined with gold-beaters' skins. Gasbags will be fitted to automatic relief valves and hand control maneuvering valves.

Machinery Cars.-Six machinery cars are provided, each containing one engine installation, with a direct-driven propeller fitted at the aft end. These compartments give the mechanics easy access to each of the six engines, and allow them to handle all parts of the machinery. Engine room telegraphs of the electrical type communicate between the forward compartment and each of the machinery cars.

Whereas the living quarters and the control compartment must be heated by electric radiators, arrangements can be made to warm the machinery cars by utilizing the exhaust heat. The transmission gear in two of the wing cars is to be fitted with reversing gear, so that the craft may be driven astern. So that passengers shall not be worried by the usual roar of the exhaust, special silencers will be fitted. The transmission gear is also so arranged that all unnecessary clamor from it may be avoided.

The engines run on gasoline fuel, but they have devices whereby they can be run alternatively on hydrogen gas. They are designed to develop their maximum power at a height of five thousand feet.

Telephones.-Telephone communication links all stations on the airship.

Landing Gear.-Inflated buffer landing bags of a special type are to be fitted underneath the Forward Control Compartment and underneath the two Aft Machinery Cars. These enable the airship to alight either on land or on the sea's surface.

Wireless Telegraphy.-A powerful wireless telegraphy installation is to be fitted in the wireless cabin in the forward control compartment. It will have a range for sending and receiving of at least five thousand miles.

Crew.-Two watches would be required, taking duty in eight-hour shifts. Both must be on duty when the craft leaves or lands. Each watch consists of navigating officer, steersman, elevator man, four engineers and a wireless operator. With the commanding officer and two stewards, whose duties are not regulated by watches, the crew thus numbers nineteen men.

Although the speed of the airship at maximum power is seventy miles per hour, the crossing normally would be made at sixty miles per hour, which only requires two thousand horse power, and is much more economical in fuel. The full speed, however, can be used whenever the ship is obliged to voyage through storm areas or against strong head winds. By the Azores route, the time needed for the journey of thirty-six hundred miles, at a speed of sixty miles per hour, is sixty hours; but to allow for delays owing to adverse weather, the airship would always carry eighty hours' fuel, allowing for a speed of sixty miles per hour. The normal time for the journey from London to New York, via Portugal and the Azores (thirty-six hundred miles) would be, therefore, two and one half days. The normal time for the journey New York to London by the direct route (three thousand miles) would be just over two days.

The prevailing wind on the direct route is almost always from West to East, which favors the Eastbound journey, but is unfavorable to the Westbound journey. It is proposed that the crossing Eastward from New York to London be made by the most direct route, advantage thus being taken of the Westerly winds.

By making the Westbound journey on the Southerly route, via the Coast of Portugal and the Azores, and on 35′ N. parallel of latitude across the Atlantic, and then to New York, the voyage is made in a region where the prevailing Westerly winds of the higher latitudes are absent, and only light winds are encountered, generally of a favorable direction. This route, however, adds about six hundred miles to the distance. With a ship speed of sixty miles per hour, it would be quicker to make the Westbound journey by the direct route if the Westerly wind did not exceed ten miles per hour. If the wind were greater, time would be saved by covering the extra six hundred miles of the Southerly route and dodging the unfavorable air currents.

With four airships on the Cross-Atlantic airway, two only would be in service at a time, so that each could lay up during alternate weeks for overhaul and re-fit. As the time of journey between London and New York will vary between fifty to sixty hours, each airship can easily make two crossings or one double journey per week, thus giving a service, with two dirigibles, of two "sailings" each way per week.

The average time table might therefore be as follows:

Leave London Arrive New York

Thursday morning Wednesday afternoon or evening

Monday morning Saturday afternoon or evening

Leave New York Arrive London

Monday afternoon Thursday morning

Thursday morning Sunday morning.

From available weather reports, it is considered that crossings are practicable on at least three hundred days in the year. Probably a total of two hundred crossings in the year could be maintained. Until further study of weather conditions supplies a certain knowledge of the best possible altitudes and latitudes, it is likely that a regular service of two crossings each way per week will be maintained only in the months of May to September, and that the crossings from October to April will be irregular, the day of departure being dependent on the weather.

Weather difficulties are likely to be much less severe than might be imagined. Rain, hail and snow should have little influence on the navigation of airships. An outer covering that is rainproof and non-absorbent avoids the absorption of water and the consequent increase of weight. Hail and snow cannot adhere to the surface of the craft when in flight, owing to its high speed through the air; and, in any case, the precipitation height being not more than eight thousand feet, they can be avoided by flying above this altitude.

Fog may give trouble in landing, but during the journey an airship can keep above it. If the terminal were enveloped by fog an arriving ship could pass on to an emergency landing ground away from the fog-belt; if the mistiness were slight, it could remain in the air until the ground were visible, making use of its margin of fuel beyond the amount necessary for the London-New York flight. Airships in fog may be enabled to find their landing ground by means of captive balloons or kites, and of strong searchlights from the ground. At night, the balloons or kites could carry electric lights, with connections from the a?rodrome.

In any case, fog, rain, hail and snow are nearly always local in their occurrence, and can be avoided by a short deviation from the usual route. Atlantic records indicate that on the main steamship routes fog sufficient to impede navigation does not occur on more than about twelve days in the year.

Wind is a factor that needs more careful study in its relation to transatlantic air navigation. In most cases, unduly strong winds can be dodged by flying on a higher level, or by cruising on a different course, so as to avoid the storm belt. Heavy storms, which are usually of a cyclonic nature, rarely cover an area of more than two hundred miles diameter. Moreover, the rate of progression of a cyclonic area is much less than the speed of the air movement. An airship is able to shake off a cyclonic area by a deviation from its course of not more than two hundred miles. Once away from the storm belt, it has no difficulty in keeping clear of it.

When higher levels of the air have been charted, there is every reason to believe that the known movements of the Atlantic winds will be used to shorten air journeys. There are at sea level, between certain clearly defined latitudes, prevailing winds of constant direction. At greater heights, also, there is in most latitudes a constant drift which, if charted, might be useful even if winds at sea level were unfavorable.

Although precise information is available of the prevailing and periodic winds at sea level in various latitudes, very little co?rdinated work appears to have been done in charting the prevailing and seasonal winds in higher levels of the atmosphere. Observations of the air currents over various localities in the United States, England and Germany have been taken, but very little is known of the winds above the great ocean tracts. There is a great necessity for international research to provide data for predictions of weather conditions in the upper atmosphere and thus enable advantage to be taken of these higher currents.

At high altitudes, constant winds of from thirty to forty miles per hour are common. If the prevailing directions of those were known to airship navigators, the duration of the journey could be considerably shortened, even if this meant taking an indirect route. It is undesirable to fly at great heights owing to the low temperature; but with suitable provision for heating there is no reason why flying at ten thousand feet should not be common.

Air currents cannot be charted as exactly as sea currents; but much valuable work can and will be done by tabulating in detail, for the guidance of air navigators, the tendencies of the Atlantic atmospheric drifts. Reliable charts, used in conjunction with directional messages from wireless stations and ships, may make it possible for vessels on the London-New York air service always to avoid troublesome winds, as well as storms and fogs, and to reduce the percentage of risk to a figure not exceeding that relative to sea liners.

For the rest, the excellence of the most modern engines and the fact that one or two, or even three of them can be temporarily out of action without affecting the airship's stability during a flight, minimize the danger of a breakdown from loss of power. The only remaining obstacle to reasonable safety would seem to be in landing on and departing from the terminal during rough weather. This can be overcome by the recently patented Vickers Mooring Gear for Rigid Airships.

The gear, designed so as to permit an airship to land and remain moored in the open for extended periods in any weather without the use of sheds, consists principally of a tall steel mast or tower, about one hundred and fifty feet in height, with a revolving head to which the craft is rigidly attached by the nose, permitting it to ride clear of the ground and to turn round in accordance with the direction of the wind. It is provided with a hauling-in winch and rope to bring the ship up to the mooring point.

An elevator, for passengers and goods, runs up the tower from the ground to the platform adjoining the nose of the airship. The passengers reach their quarters along a passage through the vessel, and the goods are taken down a runway. An airship moored to this mast can remain unharmed in even the worst weather, and need be taken into a shed only when overhaul and repairs are necessary.

In discussing the future of transatlantic flight I have confined myself to the projected service between London and New York. There is likely to be another route over the Atlantic-London to Rio de Janeiro, via Lisbon and Sierra Leone. Already in London tickets are on sale at $5,000 apiece for the first flight from London to Rio. This, of course, is a freak price, which covers the distinction of being in the first airship to travel from England to Brazil. If and when a regular London-Rio service is established, the ordinary passenger rate should be little more than the $240 estimated as the air fare on the London-New York route.

It may be that the London-New York air service will not arrive for many years. Sooner or later, however, it must arrive; for science, allied to human enterprise, never neglects a big idea. It may be that, when it does arrive, the structure of the craft and the methods of navigation applied to them will differ in important details from what I have indicated. I make no pretense at prophecy, but have merely tried to show how, with the means already at hand, moderately priced air journeys from Europe to America can be made in two to two and a half days, with comfort, safety and a high degree of reliability. Meanwhile, much depends on the funds available for the erection of stations for directional wireless messages, on research into the air currents at various levels above the Atlantic Ocean, on the courage of capitalists in promoting what seems to be a very speculative enterprise, and on new adaptations of old mechanical inventions.

Already hundreds of a?roplanes, as time-saving vehicles, are used regularly in many countries for commercial traffic over comparatively short distances-the carriage of mails, passengers, valuable freight and urgent special journeys. When, but not until, the hundreds become thousands, and the longer distances are as well served by airships as are the shorter distances by a?roplanes, the world's air age will be in sight.

[1] For airships with gross gas capacity of 3,500,000 cubic feet and total load of 105 tons.

[2] For machines with total load of 40 tons.

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