Seaplanes cannot be used for long-distance flights. It will be remembered that the seaplane flown by Commander Rodgers in 1925 in the San Francisco-Honolulu flight came down 200 miles from Honolulu for want of fuel. The first successful crossing, in June 1927, was in an Army aeroplane, and Lieutenant Maitland reported that 'sufficient gasoline for another 600 miles' was left in his machine. Again, the first nonstop crossing of the South Atlantic was achieved by aeroplane. On October 15, 1927, two French lieutenants, Costes and Le Brix, flew the shortest sea passage, a distance of 2000 miles, in 21 and a quarter hours. All the previous crossings had been accomplished by stages in seaplanes.
The opinions of naval men can well be quoted here. Admiral Sir W. H. Henderson, putting the matter in a nutshell, says: —
The seaplane or flying boat offers a chance of a few hours of life to derelict airmen, but, conversant as I am with Atlantic weather conditions and the difficulty of locating an aeroplane in an ocean, I would prefer to trust my life to the extra fuel possible in a landplane.
Commander F. L. M. Boothby, R.N. (Retd.), reminds the public that
The flying boat, advocated by some, is at present less efficient than the aeroplane in the air and slightly more so on the water. A sea that would rapidly break up an aeroplane could be ridden out by a flying boat, but it would last next to no time in an ordinary heavy sea.
In the opinion of Admiral Mark Kerr,
It is unlikely that the biggest flying boat of the present time would last more than a few hours on the Atlantic on 300 days of the year.
Seaplane services are being tried out. A transport company essayed a mail service on the Khartum-Kisumu route with a seaplane, the D. H. 50 Pelican. It was damaged in a test flight in January 1927, and the Air Ministry lent the company a seaplane while the Pelican was being repaired. But this borrowed seaplane promptly sank in Lake Victoria Nyanza. At last, on October 9, the Pelican was prepared to resume its work, yet no sooner were air-mail facilities announced than they were suspended—the Pelican had crashed a second time in a test flight.
It is generally recognized that air machines, wonderful as they are, are still far from being satisfactory; that especially in weight-carrying capacity there is room for radical improvement. Any criticism, however, of the shortcomings of aircraft or any statement of their inherent limitations is met at once by the retort that 'aeroplanes are in their infancy'; that, given time and money for experiment and research, difficulties will be overcome, 'the air will be conquered.' Repeated disappointment and dreadful tragedy are met by the plea that aeroplanes are not yet properly developed, the study of aerodynamics is not sufficiently advanced—and the public is persistently led to expect great improvement in aeroplanes and much practical advance in the art of mechanical flight.
But consideration of the matter will show that flight became possible only after the introduction and development of an engine of light weight per horsepower,—the internal-combustion engine, —and that this engine, continuously improved and developed during the last thirty-five years, has now in all vital respects reached its limit of perfection. All engineering knowledge accumulated since the dawn of the mechanical age has gone generally to the design and construction of the aeroplane as it is to-day; twenty-five years have been devoted to this specialized branch of engineering—mechanical flight. All of the body of knowledge from the common stock has been available and intensively applied to the development of aviation, at fabulous cost to the taxpayers of all nations.
Engineers and experts are agreed on the point that the aeroplane has long passed its experimental stage. Sir Alan Cobham, the famous long-distance pilot, referring to his Australian flight, says, 'From a mechanical point of view the aeroplane was as near perfext as any form of transport can be,' and neither Colonel Lindbergh nor Mr. Levine had any failt to find with their engines or with their planes—albeit their engines were not new types, and were of designs that had been years in use. Major de Havilland, a well-known manufactuerer, states:—
There is no revolutionary change to be expected in aeroplanes. Design is more or less stabilized, and it is only in details, in materials, in strength and lightness, that any alteration may be looked for.
The maximum weight that an aero-engine can lift and carry is practically fixed. The engine itself is light; the big factor, apart from the weight of the plane itself, is the fuel it requires. In a long, spectacular flight all the available load must be taken in fuel to cover the distance; no freight can be carried; all but the barest necessities must be left behind. Paying freight can only be taken when the distance is strictly limited: the shorter the distance, the less fuel required, and the more weight left for freight. This at once shows that the aeroplane, for any practical purpose, is a short-distance vehicle of transport. Moreover, common sense indicates and experience proves that, if safety is aimed at, the structure of the vehicle should not lack strength and the limit of loading should not be approached; if comfort is desired, some part of the paying load must be sacrificed. All these factors further reduce the load of fuel that can be carried, the distance that can be covered. 'As a matter of common knowledge,' states the Secretary-General of the Air League of the British Empire, 'a commercial machine carries but little more than the maximum paying load. Moreover, both passenger and freight are carefully weighed in order to ensure there shall be no overloading.' When strong adverse winds are encountered the restricted amount of petrol carried may not last out and a forced landing becomes inevitable. For the air journey of some 200 miles on the cross-Channel service, when weather conditions are not too adverse, twelve to fourteen persons are carried by the new large passenger planes with engines developing 1200 horsepower. It is worth contrasting the useful achievement of a similar horsepower when relying on gravity instead of resisting it. A great train rushing smoothly and swiftly along rails, irrespective of weather, at a rate comparable to the speed of a heavy aeroplane, presents the most startling contrast in effort and achievement. The famous railway engine King George V can run, it is said, at nearly 100 miles per hour and draw 'almost any load.'
It is not difficult, therefore, to understand why the 'air' cannot compete with older and cheaper forms of transport—why aviation fails to pay its way. Colonel Lindbergh, speaking on the commercial aspect of the air mails in the United States said:—
Our mail service is in a few cases on a paying basis. By a paying basis I do not mean that there is any margin, any large margin of profit. Most of these air lines are just about holding their own or losing a little each year.
Air mails are thus not very profitable in the contractors. The expense of United States air-mail service ending June 30, 1926, was $2,944,648. The total receipts for the same period were $980,271:—A loss of $1,964,377 chargeable to public funds. For each ounce of letter mail carried by air mail from Boston to New York the contractor is paid over eighteen cents; twenty cents is paid by the sender, and government subsidy supplies the balance.
All existing air routes, indeed, are dependent upon subsidies. If they were cut off, civil aviation would practically come to an end. The cost to the British taxpayer of every mile flown by Imperial Airways on home routes is 3s.4.5d., or £70 for the return journey Croydon-Paris: on the route Cairo-Basra every mile costs the taxpayer £1, or £1200 for each completed flight; and in addition further aid is given in the provision of landing grounds, petrol stations, and sheds. Germany has a network of air routes, but 70 per cent of the cost of German aerial transport has to be obtained by taxation or subsidy, this assistance amounting to the enormous sum of £2,137,000 yearly; and though each passenger receives free insurance with his ticket, and other encouragements to air travel are given, the machines, it is said, usually leave half full. The subsidies paid by France to aviation companies have aggregated 60,000,000 francs, yearly payments being based on mileage, and additional help has been given through the purchase by the Government of new types of machines destined for civil purposes. In October 1927, the French Government resolved to ask the Chamber to sanction further expenditure which will commit it to spending 140,000,000 francs, or $5,650,000, a year on civil flying for a period of ten years.
Leaving profit out of the question, how is the gulf between subsidy and solvency to be bridged? How is commercial success to be achieved for aviation? It is not by further development of the aero-engine, for that has practically, if not quite, reached its limit; not by increasing the size of the planes, for no real saving is thus effected, except in pilots. Engines are as reliable and aeroplanes nearly as perfect as they can well be; external aids are now supplied in plenty, and aerial pilots are expert, ready, and resourceful. Though small improvements will undoubtedly take place, there can be no specific increase in performance. For any spectacular improvement we must await some quite new discovery—some new phenomenom, upon the nature of which it is idle to speculate. It involves a new source of motive energy, any energy which implies little or no weight, but gravity will still exercise its unfailing force, and the wind will continue to be beyond the control of man.
As things are, flying is too expensive a mode of transport to be considered by the ordinary man or woman. To the great majority with means, the deafening roar of the engines, the sense of danger, the great uncertainty, added to the not inconsiderable fare, more than balance the possible gain in time. There remain the few with the desire and the means to travel by air, which they do at considerable cost to the State.
Under special circumstances for emergency transport, aeroplanes may be of great service. Banks find aeroplanes useful for the carrying of bullion across the Channel and between cities not too far apart, but the real advantage or desirability of these and other services can only be tested when state subsidy ceases and civil aviation flies by itself. In undeveloped countries, where other means of rapid transport are not available and where flying conditions are good, aeroplanes may prove of distinct value, and their use justified in providing medical aid and communications to 'back blocks'; they do it, however, at a cost which must entail considerable assistance from public funds.
The poverty of the demand on the part of the public for aeroplanes as vehicles of transport is a perpetual disappointment to those interested parties and leagues who are concerned in creating what is termed 'air-mindedness' among the people. Even the sport of flying is not carried on without government encouragement, and the race for the Schneider Cup has now become a contest between Air Ministries and a further addition to the heavy burden of taxation.
Though subsidies now support aerial transport in every direction, and propaganda seeks to popularize it, eventually civil aviation must be left to fly by itself; and, while economic factors determine its scope, the aeroplane will remain a vehicle of emergency and quick transport under conditions favorable to its use, reasonably safe for comparatively short distances, perilous on long flights, with freedom of route denied to other vehicles of transport, yet governed in its incomings and outgoings by the inconstant wind. But the force of gravity ever pulling the plane and its load to earth, will ever set a limit to the achievements of aircraft and be the insurmountable barrier to commercial success in the air.