WHEN one flew from coast to coast on the express passenger schedules of 1933, twenty-one hours of traveling time was making first-class speed. Before the second month of 1934 was out a new type of transport plane crossed the continent in thirteen hours — two hundred and twenty miles per hour through winter blizzards.
We are on the threshold of a new era in flying, for 1935 points inevitably to speeds of three hundred and four hundred miles an hour.
Now, if ever, is the time when the airways need not only the support of the public, which they have always had, but the energetic coöperation of the government. I am not referring here to the recent air-mail controversy; what I suggest is government coöperation in solving a specific technical problem, the solution of which would revolutionize the entire future of aviation. To make this coöperation effective it will not be necessary for the government to become involved in the operation of the air lines; these are the product of years of experience and organization, and a change in the control of such intricate systems might well be disastrous to all concerned. It has been amply shown that the task belongs to the professionals. It is in initiating the scientific development of certain new principles into uses at once valuable and spectacular that a wonderful opportunity exists for the government to take the lead. It
If we are to maintain our leadership in commercial flying, — so hardly won and splendidly maintained, — constructive action is essential, if only in the self-interest of the government.
In France and in Germany planes are being designed to cross the Atlantic in six hours. New vistas are opening, based on new conceptions of speed and distance. Horizons shrink. In this new picture of world communication, of new routes and schedules, not only across our own continent but across all the continents and oceans of the world, it will be a calamity if American prestige cannot be retained.
These great speeds are coming, but not as a result of something yet to be invented. They will come as a result of applying and combining three inventions that have recently been perfected — the variable-pitch propeller, the altitude supercharger, and slow-landing wings. These inventions, with all their subsidiary details, have yet to be interlocked, just as the spring, the cogs, and the escapement of a watch must be meshed before we have a timepiece.
It is by now generally accepted that the high-speed planes will be altitude planes. I do not refer to the stratosphere, to the researches of Piccard and Settle in the upper air. Stratosphere flying is certain to come, but for the present the idea is rather Wellsian— eventually practical, but born too early. The new method will be simpler.
The six-miles-a-minute machines will be quite ordinary-looking planes. A passenger going aboard for Europe, South America, or the Orient would be unlikely to detect anything unusual about them. He might, if he looked closely, notice a slight protuberance around the hub of the propeller; if the engine covers were off, he might notice a gadget like a rather complicated air pump; he might see that the door of the passenger cabin fitted very closely and that it had a special handle. But that would be all.
Amazing new air services will be as familiar to him as the runs of the ‘Twentieth Century Limited’ and the sailings of the Bremen are to us. Here, for example, are a few typical journeys showing the fastest surface transportation, together with the old and new schedules by air: —
|Surface||Old Air||New Air|
|New York to London||5 1/2 days||None||10 hrs.|
|New York to San Francisco||4 days||21 hrs||8 hrs.|
|San Francisco to Tokio||14 days||None||20 hrs.|
|Chicago to Buenos Aires||21 days||8 days||28 hrs.|
|Boston to Washington||9 hrs||4 hrs.||80 min.|
Kipling’s vision of ‘ The Night Mail’ will pale before the sheer matter-of-fact routine of the departure of the European Express from Newark every evening. Yet how prophetic was the title of the great story!
When the first excitement has worn off, it will become commonplace enough. The office boy, licking the special stamps, may feel a flickering remnant of dime-thriller romance, or picture a sort of Norse Nick Carter, metalhelmeted, roaring under glittering stars around the curve of the world. But the letters, prosaically, will just drop down the chute at 5 P.M. and be uneventfully delivered at the sooty General Post Office in Cheapside the next morning at nine.
The British business man, because of the difference in time, will have until midnight to catch the U. S. Mail; or going in person, directly from the theatre perhaps, he will retire to his bunk as the plane leaves Croydon and wake for breakfast, around dawn, as the express is tearing over Boston. There will be no reason why the really high-pressure gogetter should not leave for Europe, make the deal, feast the victim, and be back in New York with the loss, if one may call it that, of but one business day.
The difference in time will give rise to some queer anachronisms. On the fastest service, a man will leave Paris at noon and arrive in New York before the late luncheons are over. More than that, some super-speed pilot like Hawks or Wedell or Turner may succeed in arriving earlier than he started!
Now for the actual problem of making such speeds possible.
The same air which supports a plane tends to prevent it from going forward. The engine and propeller can overcome this drag up to a certain point, and that point becomes the maximum speed of the plane. It takes a tremendous increase in power to achieve even a small increase in speed against the resisting air.
However, the higher one flies, the thinner the air becomes, the farther apart are the molecules. For instance, at twenty-one thousand feet the density of the air is only one half the density near the ground; therefore at this height each cubic foot of space contains only half as many molecules. As a plane climbs, it tries to dash forward faster because the drag is less, it tries to get the same amount of molecules around its wings to hold it up; but it cannot, because the propeller is unable to get a grip on the thin air. The engine loses power; it cannot breathe in quite enough air to mix with the gasoline. Even if the engine is supercharged, the pilot has to ‘take his foot off the gas’; otherwise the motor would turn up at such a rate that the propeller would burst and the pistons fly through the cylinder heads. When he throttles the engine, his speed decreases.
We now come to the essence of the problem. If the engine and propeller could maintain a constant thrust, they would drive the plane forward at a speed at which the total resistance would also be constant. In maintaining such an opposing pressure against itself in a thin atmosphere, the plane would have to dash through more space to find more molecules, and would achieve a much higher true speed, or ground speed.
We could take one of the latest passenger and transport ships with a cruising speed near the ground of two hundred miles per hour and obtain the following results: —
|0 ft||200 m.p.h.|
|21.000 ft||285 m.p.h.|
|28.000 ft||315 m.p.h.|
|35.000 ft||365 m.p.h.|
A queer but valuable feature of these phenomenal speeds is that the recorded air speed will always be the same (in the above case, two hundred miles per hour). This is because air speed is measured, in effect, by the resistance offered by the air, by the total impact between the plane and the molecules. This resistance will remain constant.
The problem, then, is to enable the propeller to get a bite on the thin air, to make it possible for the engine to keep turning at full power. This will be accomplished, with all the extraordinary results already touched upon, through two small but fundamental pieces of mechanism.
The first is the variable-pitch propeller, which makes it possible to vary the pitch while the plane is in full flight. When the plane is on the ground, in thick air, the propeller blades will be set at a very fine angle; this will give a quick take-off and reduce the hazard of engine failure near the ground. As the machine rises, the pilot, by turning a handle on his dashboard, will increase this angle until, when he reaches high altitude, the blades will be at their maximum setting, presenting a wide area which will enable the propeller to grip the air and thrust it back. The effect is, as it were, to put the plane into high gear.
However, the variable-pitch propeller is comparatively useless by itself; to realize its potentialities a second piece of mechanism is required.
This is avariablesupercharger. When a plane reaches high altitude, the carburetor cannot suck in enough air. It is like trying to run a car at full speed with the choke out. Without ‘supercharging’ — some means of delivering more air to the engine — the pilot must constantly cut down the gas. This condition is well known, and superchargers have been built to cope with it. But for the new high-speed planes a special form of supercharger will be necessary; it must be infinitely variable, so that it can be synchronized with the propeller. Otherwise an altitude supercharger would deliver such an excess of air near the ground that the plane would have difficulty in getting off.
These two inventions unlock the door to enormous speeds. A third device will be combined with them in the interest of additional safety; it is the wing flap. This is a long strip on the trailing edge of the wing. When the flap is pulled down by the pilot it adds to the curvature of the wing, which increases both the lift and the drag, so that even a fast plane can be landed slowly.
The task that lies ahead is to work out the proper combination of these inventions. Each one, by itself, has been tried, and its practicability demonstrated. All that remains is to assemble them, to find out all the exquisite interactions which occur in flight, and to work out the necessary adjustments.
This is not an easy task, but neither is it mysterious. It does not involve splitting the atom, nor does it call for a revolution in metallurgy. There is nothing insurmountable in the problem. It is simply a matter of coördinated, practical testing.
It may be asked, ‘ Why are the blades not set at a big angle at the outset?’ The answer is that the engine could not turn the propeller fast enough in thick air to get the plane off the ground. Or, ‘If this thing is so simple, why has it not been done long ago?’ In the first place, it is a complex piece of engineering, and, in the second place, the great airplane users and their designers, including the government, have been asleep at the switch, and until very recently the designers have not been encouraged to make any serious attack on the problem.
Subsidiary alterations in design will be necessary. The chief of these will be in the passenger cabin. It will be tightly closed, mechanically ventilated, supplied with adequate air from a cabin supercharger, and heated, as at present, by the engine exhaust. This cabin work is a straight engineering problem, but, since nothing has yet been done in this direction, it will require research and careful testing. The problem can be solved to a point where passengers will be less inconvenienced in altitude flying than in taking a subway trip through the Hudson Tunnels or going up and down in the elevators of the Empire State Building.
To summarize, the new planes will take off at normal speed as at present. They will climb, at a far faster rate than is now possible, until they level off at around 21,000 feet. At that or greater height they will fly at between three and four hundred miles per hour ground speed, high over any storms, and when they reach their destination they will glide down and land more slowly than the old 120-miles-per-hour planes.
At their cruising height there will be no bumps, no clouds to blanket the sun and stars. The strain on the airplane will be no greater than now, because, although flying faster, it will be moving through thinner air, with less resistance. There will be no increase in the fuel consumed, for the throttle will remain at the same setting from the beginning to the end of a flight.
Safety takes precedence over speed, economy, or any other consideration in air transport, particularly in this country. Safety, then, is the first yardstick with which to measure a new idea.
It is not generally realized that nearly 200,000,000 passenger miles per year have been flown on our transport lines, and that, statistically speaking, the average passenger can expect to fly a distance equivalent to one thousand times around the world before a mishap overtakes him. Whatever the future may hold for aviation, it is unlikely that our great airways of to-day will ever be surpassed as far as extraordinary organization and minute care are concerned.
The air-mail ‘scandals’ have been featured in the news; some of the ‘higher-ups’ have been at the bar of public opinion; but nothing can take away from the achievements of the operating personnel who have conceived, organized, and run the finest airways in the world. It is the equipment, not the operating plans, that must be improved.
The majority of accidents occur during take-offs, landings, and in bad weather.
The first possibility of danger in a flight is just after the take-off. It may happen once in a thousand times that the power plant fails before the machine is high enough to manœuvre freely to a landing; then there can be disaster. The short run and the fast take-off, made possible by variablepitch propellers, will do much to reduce this hazard.
Landing presents possible difficulties. A large part of the problem of preserving the safety of the passengers is to apply the plane slowly to the earth. The financial necessity, from an operating point of view, of achieving higher flying speeds has already resulted in excessive landing speeds. A fast plane of conventional design lands very rapidly, for when if is brought down to earth the speed must be such that the various controls will ‘ bite’ on the air. From the passengers’ point of view, it is hard to justify landing transport planes at seventy or eighty miles an hour. At a great terminal airport with concrete runways, it is not of so much moment, but in the case of a forced landing or an attempt to get down in a mountain field the pilot may have to put down a fiveor six-ton transport under conditions where a hair-line fault of judgment, or the slightest overweighing of the scales against him, will cause a bad crash.
But with the perfection of the devices I have mentioned, which will give such enormous reserves of speed at altitude, the necessity for employing semi-racing planes will disappear. The more moderate design, employing ‘flaps,’ which have already proved their efficiency, will enable altitude planes to be brought in at fifty miles an hour; they will take an exceptionally short run — one quarter the normal — once the wheels are on the ground.
For that matter, landings will be fewer, since the new era of speed will mean a new era in airway operation. The coast-to-coast ships on the Northern run, for instance, will doubtless have only two stops, instead of eleven as at present — Chicago and, say, Denver or Salt Lake City. Territory between these places will be served by slower planes at lower altitudes, picking up passengers at Cleveland, Toledo, Des Moines, Omaha, Cheyenne, and so on, and concentrating them at the express stops. As traffic increases, we shall naturally have the aerial ‘Overland Limited,’ a non-stop extra-fare plane, capable of departing from New York at 2 P.M. and arriving in San Francisco or Los Angeles at 7 P.M. Pacific time.
The last but chief possibility of danger in passenger flying is from the weather. By means of a close network of weather stations, range beacons, and two-way radio equipment, this hazard has been enormously reduced in the past five years. Nevertheless, it has by no means disappeared. There are times when pilots still have to fly ‘blind’ by their instruments, and this is fundamentally unsound. The altitude planes, even at 20,000 feet, will be high above all ordinary storms, and, if the apex of some super-storin reaches this level, at such enormous speeds it would need only a slight pressure on the rudder pedal to carry the plane clear around it. Indeed, the pilot could afford to go fifty miles off his course if need arose — he would only lose ten minutes.
The altitude planes will make good use of the upper-air wind currents, which the government is charting with this end in view. For instance, it may be found that at a certain altitude there is a constant westerly gale which will cut the Atlantic crossing to eight hours, while at another level or latitude there is an easterly gale which will do the same thing for the westerly crossing. Cases not dissimilar have already been encountered, as witness the fact that recently two United Air Lines planes, flying simultaneously in opposite directions, — one from Seattle to Oakland at 8000 feet, and the other from Oakland to Seattle at 3000 feet, — each made a record trip.
Pilots will still have to come down through the weather to land, but again the altitude planes will have the advantage of enormous radius in a short time. Perhaps a transatlantic plane coming in over Ireland at three to four hundred miles per hour will receive word that London, possibly the whole of the South of England, is blanketed in zero-zero weather. A few words from the desk microphone of the London Superintendent will inform the pilot that Liverpool or York or even Edinburgh is open; in such an exceptional emergency the pilot may land at any of them. The farthest will be only ten minutes off his base course.
From the operating point of view, there is one final boon to be derived from high-speed flying: that is, it will be less taxing on the crew. In fact, the new era may even bring about a decrease in the more dramatic qualities required of transport pilots. The present men possess extraordinary qualities of skill and judgment, born of necessity and of the hard experience of pioneering in that recent era when they had no radio, no lighted airways, no reliable engines, not even any accurate weather data.
We can imagine a graying veteran who flew the Transcontinental Mail in 1926 talking to the air-liner captain of 1936 in much the same way as the hard-driving master of a Cape Horn clipper might talk to a captain of a Diesel-electric liner of our day.
To us, as to other nations, the gift of speed is destined to become a twoedged sword. As swift communication becomes common throughout the world, the effect on our national defense will be formidable.
Our coast-defense planes will command a radius of action of nearly three thousand miles. For example, a Navy plane will be able to fly a thousand miles out to sea, descend near the surface, scout a sector of several hundred miles, climb back to altitude, and return. Between them, the Army and the Navy will be able as a matter of routine to cover the entire Pacific triangle between Hawaii, Seattle, and Los Angeles, not merely once but several times a day. It will be possible for them to scout at least a thousand miles west of Hawaii, and it will take them but three hours to reach a point where an enemy fleet, advancing to attack, would still be forty-eight hours from the Islands.
Again, take the problem of the Panama Canal, our main artery of national defense. Here is the one route by which our fleet can be moved expeditiously from coast to coast; yet, because of its small size, it remains unpleasantly vulnerable. Automatically, in the new era, it will become safer, except, of course, in case of a direct air attack. But it will be impossible for an enemy, even with maximum luck in the way of secrecy and evasion of our surface vessels, to bring his fleet within a thousand miles of the Pacific entrance of the Canal without detection; while, from the Atlantic side, defending planes will probably spot the enemy when his vessels are still at five days’ steaming distance from Colon.
With regard to a direct air attack, a great deal of nonsense has been written about the frightful casualties that may be inflicted upon our civilian population by hordes of hostile bombers. A big bomb has a terrible effect, but it is local. The real terror for the civilian population during the next war will be from gases that are intensely poisonous, and perhaps from bacteria as well. Consider a comparatively modest force of, say, two hundred planes making a night attack upon a city. They will be able to approach at a speed of at least six miles a minute and at five miles of height, invisible to any searchlight. Even were they visible, they would be immune to anti-aircraft batteries. Such a squadron could drop at least four hundred tons of containers packed with poison gas under high pressure. The gas would be odorless. There would be no warning. Thus it is conceivable for a city like Washington to be covered with a sea of fumes ten to twenty feet in depth, exterminating all within it, and thus paralyzing for days and even weeks the seat of government.
These grim possibilities are far from unreal. Chemical warfare is in preparation throughout the world, and it is a dreamy sentimentalist indeed who imagines that this most terrible method of inflicting mass death wall not be used to the limit of its horror. It will be the first time in history that one Power can strike dowm the civilian population of another long before the military forces come in contact, perhaps within half an hour of the declaration of war. It is a grisly speculation, but one that must be faced.
One compensating fact, of course, is that the possibility of high-speed offense will also mean high-speed defense. An attack such as the one described cannot be turned away by defending planes once it is over a city, for aerial combat is difficult to wage in darkness. Further, it takes time to climb to five-mile altitudes, and every minute during which defending planes are climbing will speed the attacking planes six more miles along their return trip.
It will be imperative, therefore, to seek and destroy the enemy planes and their carriers while still far out at sea, before they can attempt, let alone complete, what might easily be the decisive stroke of a whole war.
In view of all this, it will be seen that there is great necessity for a definite programme which will make the perfection of the new high-speed devices a reality. The commercial possibilities are too obvious, the exigencies of national defense too insistent, to permit us to await the normal hit-or-miss processes of the aircraft manufacturing industry. The experimenting, adjusting, designing, and testing that must be undertaken to produce successful highspeed planes will call for coördinated effort, and the logical agency to look to for that is the Federal Government.
Notwithstanding recent headlines, the air transport companies have not, as a whole, achieved earnings on the money invested in them. The basic reason is simple. To make money, the air lines must obviously have greater volume of mail and passengers. To gain volume, the service must be quicker and cheaper. The way to lower operating costs lies in higher speed, and this is why the air lines have been buying swifter equipment. But it is not yet swift enough. To develop planes that are fast enough to solve the financial problem of the companies, a definite programme of technical research and experimentation must be undertaken, and this is where the government fits into the picture.
In the past the government has been of inestimable aid in helping private enterprise to build up our vast network of air lines. Without the technical equipment installed by the government when air transport was in its infancy, the United States could not have achieved its present position in air development. Previously we had lagged far behind Europe. The government then made a large investment to promote aviation, through mail subsidies and by providing a magnificent system of weather stations, radio beacons, emergency fields, and lighted airways. As a result, the routine traffic at Newark Airport alone is to-day greater than that of the Croydon, Le Bourget, Tempelhof, and Vittorio terminals combined.
This is what government coöperation has already helped to accomplish. And now, in much the same way, the government can do another great service to the nation — and at little cost. Let it be emphatically stated that the government is not called upon to engage in any such calamitous project as the nationalization of the airways. The job which the government is preeminently fitted to do is to sponsor a definite programme of technical development, to undertake a rationally planned effort to solve the problem of speed, instead of leaving it to the wellintentioned but unsystematic experiments which the private companies are now carrying on.
The project presents no extraordinary difficulties. Through the Department of Commerce or the National Advisory Committee on Aeronautics, with its resources at Langley Field, — or perhaps through some new agency to be created, — the government could command the services of the finest technicians and pilots from the Army and Navy, as well as from the aircraft industry, to coöperate in the work. By test, alteration, and retest, it would then be possible to design and adjust planes, superchargers, and propellers — in short, to work out a practical and efficient model for high-speed planes. Though embracing many details, new and unexplored, the project is a thoroughly feasible one, and could be carried through to completion in a comparatively short time.
The government already has, in the National Advisory Committee on Aeronautics, a body which has been financed by public funds and which has, in the past few years, made very valuable contributions to the whole art of flying. It has carried out innumerable pieces of research; indeed, it was the only body competent and equipped to undertake such work. If the National Advisory Committee on Aeronautics, or some similar agency, were given adequate funds to complete the technical development mentioned in this article, it would revolutionize flying. As a direct result, the government would save large sums of money not only on its military aircraft but on its mail subsidies, which it clearly expects to continue in one form or another. Thus the venture would be a paying proposition for the government, and a great boon to the country at large.
As individuals we may approve or disapprove of the new era of speed and of the contraction of the world which it will bring about. That makes no difference, for it is surely coming. The picture I have drawn of future possibilities may appear incredible, but flying speeds of from three to four hundred miles an hour will be as nothing compared to the miracle of flight itself. They are not as incredible as the idea of a modern transport plane — lighted, heated, radio-equipped — would have seemed to us when the Wrights undertook their first experiment. They are not as incredible as a vision of our dense airway network of 1933, operating day and night, piling up more than 3,000,000 passenger miles a week, would have appeared to us only five years ago.
Abroad, the best aeronautical minds are concentrating on experimental work. If we are to retain our standing, it is high time for American designers and operators to make a move, and for the government to realize that our future in the air is not just a matter of private and domestic concern, but one of national and international importance.