THE temptation to speculate about the future of flying is very strong. For likely, when posterity looks back upon this amazing age in which we live, flying will be seen to have done more to promote human welfare than any other human agency.
Yet it is wise, I believe, for some of us flyers to “keep our feet on the ground,” figuratively, at any rate, and to be conservative, and not to let ourselves be carried away by our enthusiasm so that we picture a so-called “air age” so exaggerated that it may never come.
Aviation has already been much hurt by air enthusiasts whose predictions have not panned out. Others have condemned the art without fair consideration. I try to steer a middle course between these two extremes, though I am confident that flying is going on to heights as yet undreamed.
The limitations of aircraft are several and serious. A large percentage of the power plant of an airplane must be used to overcome gravity, to keep the plane and its load in the air. In contrast, the weight of an automobile and its load is carried by the earth.
Throughout its progress aviation has had the handicap of contending every flying minute with the force of gravity, life itself the cost of failure. The railway and the automobile have not had this handicap. This is the chief reason why the plane must evolve more slowly than the automobile. However, this same slow evolution indicates an ultimately great stature.
Another limitation is that the cruising radius of an airplane does not increase in the same relation to increase in size as does the steamer and the airship. Airships will, I think, be the freight carriers of the air.
Air transportation is relatively more costly than the automobile as to construction and application. However, cost of the plane itself is gradually getting down to a reasonable figure as production increases. An up-to-date six-passenger plane can now be bought for $12,500, a figure based on production of 50 airplanes. A small two-seater for family use can be purchased for $2,000.
Operation is still expensive. Gasoline consumption of the $12,500 plane, with a 200 horsepower Whirlwind motor, is about II gallons per hour and one pint of oil per hour for a speed of a mile and a half a minute. Yet we must not forget that there are no rails to lay in aviation; no roadways to construct ; no bridges, tunnels or snow-sheds to provide.
Aviation is fortunately entering the most controversial stage of its brief life. The ranks of designers and builders and pilots are being swelled every day both from the college classroom and from the workshop. As a result, its development is, in the sense noted above, slower than it was ten years ago; but it is far more real.
Development in aircraft design will, of course, slow up as the limit of their possibilities is approached. I am one of those who think that that limit is a long way off.
I gather from talking to the layman that the thrill that comes to him when he contemplates the progress of flying is twofold: he feels a shudder at the pilot’s peril and a twinge of wonder at the possibilities of the future. The future of aviation and the dangers of flying are intimately associated. There can be no future for any forms of transportation that is not safe. As I said in the beginning, the public will never fully patronize the plane in preference to the railway until, as in the case with the latter, inter-line rivalry is on the grounds of comfort and not on the score of safety.
In the last two years we have made several great steps forward. One is, we have learned that a gas engine can be counted on for many hours of performance in the air. We knew some time ago that we could mount it “on the block” in a test shed and run it without stopping for two days. But with the polar, European, and Hawaiian flights behind us now we know that a pilot can at last depend on his engine in all sorts of weather for from thirty to sixty hours’ unbroken running. I believe the 100-hour reliable engine is at hand.
Further, these long-distance flights have established beyond a doubt the practicability of a multi-engined plane for use over areas where there are no landing places. This gives us another factor of reliability. Over France in the America our fuel was reduced to the point where two of our three engines could have held us aloft. It requires no flight of imagination to see that the large passenger plane of I 936 will likely have four or five engines (housed in the wing out of air resistance), not all of which will be required to keep their pilots in the air. Engines so housed will probably have to be water cooled.
To increase the factor of safety still more there will be special emergency devices for lightening the load which the engines have to carry. As I have related, we had such a device on the America. It permitted us to empty our fuel tank in about a minute and a half. In a huge ten-engined airplane such a mechanism might well make up the difference between what eight and seven engines could carry by an operation lasting less than half a minute.
It is conceivable that this matter of lightening the plane may be carried to the point of dropping other weights. One designer has suggested an emergency cabin to which all passengers would be brought when it became necessary to let go the main under-body so that surviving engines could keep the plane aloft. This does not mean that I favor resorting to such devices. It merely goes to show the direction in which we are moving to make passenger air service as safe as that on the ground.
Another great step forward I believe we are soon to make is the reduction of landing speed. The early Wright machine could land at 30 miles an hour. With a fair load our big planes of today require a landing speed of from 45 to 65 miles an hour. At such speeds the slightest misjudgment on the part of the pilot may lead to a serious or even fatal accident. Perhaps it is in this phase of airplane design that some of the most startling changes of the near future will come.
I think it not unlikely that there will be developed some practical forms of braking devices. These would be attachments to wings or fuselage that would permit the plane to have more supporting and wind-buffer surface during the moments just prior to touching the ground. A bird gains this effect by arching its wings and turning them up to the wind, so that it can hover for a second or two before it alights. Probably our stiff plane wings will always prevent exactly this being done. But extra surfaces that can be momentarily extended will accomplish the same result with slightly additional weight. Planes are now being built with wheel brakes so as not to run so far after landing.
On a large and well-prepared landing field under normal conditions this matter of landing speed is not so important. But now that cross-country flights are becoming more and more frequent the pilot must be prepared to land in almost any sort of cleared space. Furthermore, we are already beginning to get ready for the day when we shall have to come to a stop on the roofs of skyscrapers and high landing platforms built up like wharves. I think this day is but very little in the future.
Another point about which the layman thinks little, but which is one of the designer’s milestones of progress, is the size of the normal gliding angle of the plane. Roughly, this is the angle to the horizontal which a plane can assume and still keep maneuver· able speed. In one set of tests set forth for progress along this line the object was stated as “to demonstrate the ability of the aircraft to glide for a reasonable distance in case of engine failure and alternately to glide at a steep angle in order to facilitate the approach to a possible landing ground.” In a stalling emergency nothing could be more important to the safety of the passengers. Requirements of the test were:
First, flattest glide: The aircraft shall be able to glide with all power switched off so that the angle between the flight path and the horizontal is not greater than 8 degrees.
Second, steepest glide: The aircraft shall be able to glide with all power switched off so that the angle between the flight path and the horizontal is not less than 16 degrees. During this test the air speed shall not exceed 45 miles per hour. In both cases the aircraft must demonstrate that all the controls are definitely effective throughout the test, and that it can land safely out of this glide from a useful altitude.
All this sounds very technical. But that is true of nearly any present-day discussion of aeronautical details. Engineers have been going ahead with this new science for more than twenty years now and we are well out of the primer class. The important point I want to make is that while this business of gliding angle and landing speed may be obscure to the layman, it is in just this sort of details that our next aeronautical advances are coming.
I predict that we shall follow the example of Europe in popularizing the art of gliding without engines. I can conceive that in the next ten years there will be put on the market engineless gliders that will cost less than four hundred dollars. They will be in a class with canoes. Our young people who now go boating on the lake will then spend part of their time gliding from the hillsides. We may expect to ring the dinner bell only to find that Sally or Jim is half a thousand feet over our chimney tops where the morning breeze has taken her or him in the new glider. As a result of such a fad we should not only rapidly recruit our ranks of pilots throughout the country, but the improvement of design would naturally be helped. Closely following these two items is the matter of ascent angle. With more and more obstructions over the ground we are finding it increasingly difficult to get off with our big planes unless there is wide latitude for running before the hop. I feel sure that devices fashioned for braking on landing will also be used to help the plane get quickly clear of the ground on the takeoff.
Stability has been a mooted question since the Wrights first made their historic glides at Kitty Hawk. Designers have been working toward automatic stability for years. There are now on the market several planes in which the pilot can momentarily in smooth air leave the control while in the air and walk back among his passengers. Such stability must in the future be obtainable not only when weather is perfect, but when the plane is being thrown about by gusts of wind striking it from any direction.
A startling discovery has recently been made in England. Slots in the wing of the plane open automatically when the plane starts to stall, and so by cutting down the resistance, prevent the plane from falling into a tail spin.
We have been over the same hurdles with craft that travel on the sea. Early boats of the Nile dwellers were flat-bottomed. They had no keel or bilges. They drifted about at the mercy of every breath of air unless the oarsman was continually on the job. Now we have automatic stability in our ships that is gained in several ways. Bilge keels steady them when rolling and yawing. A large deep rudder aft prevents sudden swinging. A heavy keel, or keels, governs their leeway to a large degree. The helmsman has but to touch his wheel or lever occasionally to keep the huge Leviathan on her course.
Besides the items already listed there are some immediate handicaps to safe and efficient passenger air service throughout the United States that I believe will be overcome in the next few years, judging from the rapidity of aeronautical progress today. First, and in some ways most vital, is the fact that we are overloading our planes today when we want to make a long flight. Lindbergh’s plane was overloaded; poor Noel Davis’s was; mine was. By “overloaded” I mean carrying so much that there is great difficulty getting off the ground, as well as considerable risk in landing, if necessary, in the early stages of the flight.
Had we been forced to land the America in a restricted area during the first six minutes of our ocean flight until we could get altitude I think she would have been smashed to kindling wood. To reduce overloading we must first increase the cruising radius of the plane. This can be done in a number of ways. We are continually improving our streamlining and so cutting down resistance. We can increase the efficiency of the wing-lifting power, of the engine, of the fuel, and of the steering surfaces which with the equipment add materially to the total weight of the plane itself. We can decrease the weight of our engine per unit of horsepower. But this will come slowly from now on as we are near the limit now. Minor items such as radio and other auxiliary mechanisms are being made lighter and lighter all the time. Over-loading may dangerously increase strain on the wings ; it reduces materially maneuverability of the plane when it is near the ground.
I have already spoken of the value of a reliable engine. Failure of motor at night over land and at any time over sea or rough land, is one of the most pregnant causes of accident in all flying. I am convinced that if we can once reach the point where an engine never stalls in flight we shall not average 5 per cent. of the tragedies we have today. There are as many causes for stalling as there are parts in an airplane engine. The entirely foolproof engine has not yet been built; it never will be. But we are working toward that end rapidly; and when men can hop into a plane with confidence that they will run regularly on a set air-mail schedule such as we have today, we are pretty close to the theoretically perfect power plant.
In the next ten years I believe that our big transoceanic radio companies will organize a complete system of air radio. Ships crossing will periodically fix the positions of planes to which they have been assigned. Powerful radio stations on both sides of the ocean will keep a continual stream of radio emanations pouring out over the dark wastes of the sea like beacons of light now visible near the shore. When this sort of system is in force, a plane need scarcely use her compass at all. She will simply start off in the right direction and depend on those ashore or on the surface of the sea to provide her with course corrections as she flies.
The next problem is one that trans-Atlantic flights last summer made the first great attack upon. This was the problem of knowing weather conditions in advance of getting under way for a long hop.
When we were getting ready to hop off in May, 1927, the first regular ocean weather maps for the upper atmosphere were issued by Dr. Kimball of the New York office of the United States Weather Bureau. This was the beginning of what in a few years may become the most extensive and important work of our coastwise weather service, supplementing the land service towards which we have made considerable progress. Most persons will remember how bad conditions were during the periods immediately prior to our hop-off. The trouble was that just when one zone of the ocean route would be reported clear of fog and storm another zone would be very bad. Had we been able to get reports over a larger area, or had our plane boasted of a longer cruising radius, we might have dodged the rough spots and hopped off much sooner. In order to prove the reliability of air-craft we did not await ideal weather.
When we finally did go visibility conditions were such that we were lucky to escape with our lives on the other side. For about twenty-four hours we saw neither sea nor land. This sort of thing need not happen once regular passenger service starts. There will eventually be in operation a perfected system for knowing every hour of the day or night just how the weather is over any spot of the entire globe.
One more difficult air problem that is still unsolved is navigation of the plane. Of course, with perfect weather conditions and a good radio directive system working, the plane doesn’t have to be navigated. Over the land in daylight and a good visibility the pilot guides his machine by known landmarks.
But here we reach an impasse with which oceangoing steamships long ago were faced. The steamship pilot can pilot and depend on soundings or radio for a great deal of his cruising. But the law requires that he protect his passengers by constant proper navigational checks of his position at sea. This is done so that if other means of fixing his spot on the chart at any moment suddenly fail him he can still steer an accurate course to port. I am positive that the long-distance plane of the future will be navigated by her officers in much the same way that a ship is navigated at sea. We now have a sun compass for daylight flying in high latitude and reliable airplane magnetic compasses. But neither instrument indicates to the pilot how much his ship is drifting to one or the other side of the course as a result of the wind.
We have instruments to tell how high a plane is, and in clear weather how much she is drifting, and approximately how fast she is going through the air and over the ground. But the figures obtained are still somewhat crude. And the longer the flight in bad conditions the worse such errors become.
One of the greatest inventions yet to be made in aviation is an instrument to be used on the plane itself that will give the drift of an airplane caused by the wind when flying in thick fog or above the clouds. There are those who say that it is impossible to develop such an instrument; but I don’t believe it. Wherever there is a radio beacon available at some nearby station the wind drift can be calculated. But there should be such a fog drift indicator on the plane itself. This together with sensitive altimeter and amber colored light beacons should ultimately conquer this last foe to safe flight.
The pilot of tomorrow must be so secure in his navigation that he need not wait for perfect conditions, or depend for his results on unusual skill. He must have instruments of such accuracy and methods of such simplicity that he can achieve the same results as we did near the pole whether the weather be good or not.
Summing up, commercial aviation of the future need not be subject to any of the accidents that have made aviation thought of as dangerous. The commercial company will have the best modem equipment; highly trained fliers and mechanics; careful and competent inspection; sufficient landing fields along the route or multi-engined planes until there are sufficient landing places; adequate night lighting of fields; efficient meteorological service; perfect radio communication between field and plane; radio beacon to direct the plane on its course, etc.
There are some very special problems in addition to those listed above that project us somewhat farther forward into the future when we consider them. One is the likelihood of landing in midocean on some sort of anchored way-station. Such a device has been suggested time and time again. But an investigation of the architectural difficulties entailed is discouraging. Besides such a landing place is not practicable unless fog is entirely conquered.
No doubt there will be a period of rivalry between the airship and the plane which we scarcely foresee today. Certainly the huge investments several governments are making along the line of lighter-than-air vessels is significant. When I was in Europe last year I investigated the new British airship the R-100 which will be 720 feet long and have a gas capacity of 5,000,000 cubic feet. This will make it about twice the size of our own air giant, the U.S.S. Los Angeles. Such a ship can cruise over 5,000 miles without taking on additional fuel and she will be able to carry more than 100 passengers. Germany is building the LZ-127 which will be 774 feet long with which the Germans hope to circle the world in twelve and a half days.
In passing, it is well to mention that out new American airship will be even bigger than the German one. Its capacity will be about 6,000,000 cubic feet. Once we are confident in our weather predictions over the area of the United States such a vehicle will certainly bid for wide use as both a passenger and a mail carrier.
There is still a feeling against increasing the speed of our planes beyond what we are doing with them today. Terrific speed records of about 300 miles an hour which have been made in the last three years suggest equally terrific accidents. On the other hand, it is quite conceivable that we may soon combine our high altitude exploration with high speed flying. A figure of 500 miles an hour is, I think, in sight.
The great boon for the future of aviation is public sympathy. I do not believe that government subsidies will help it much, if at all, aviation had better stand on its own feet. What we need is private capital and individual enthusiasm. Once these two great forces are available the meteoric rise of the automobile will surely be duplicated in the coming decade by the plane.
In closing let me go back for a moment to the stirring days in France that followed our arrival there by air in the America. While sorrowing for their own gallant fliers, Captain Nungesser and Coli, the French were not inclined to be envious of our success but met us with a joyful spirit of celebration.
May it not be that aviation in the future will in much this same way become the world’s strongest instrument for peace?
Surely it brings mankind closer together, knits the interests of the world, and helps spread knowledge and an understanding without which there can be no lasting peace.
If this some day be so, then the men who have given their lives for aviation will not have died in vain.