Air power

“ Had we recognized the revolutionary character of air transport, we might have removed enough of the causes of war to have avoided World War II. Instead, we hamstrung our own air power and provided our enemies with a favorable opportunity to seize control of the air. ”

“ Though the modern closed-construction and air and heat arrangements of air-craft made flying at that height practicable enough, it was necessary by reason of the greater tenuity of the air to use more of the motors' power to attain the same speed. As we hummed on at that great height, all sight of the ocean beneath was hidden from us by the great vapor-layer that lay over it beneath us and only the pale stars above and the triangle of gleaming cruisers behind were visible to us. ”

“ It is not at all visionary to assume that the heat of the earth’s interior in near time will furnish the power necessary to do the drudgery of mankind, give warmth and light to habitations, and operate transportation systems; and the New World Above offers pure, electrified, [19] and highly stimulating air into which helium-inflated dirigible balloons will sail, and in which they will remain not only days but weeks or longer, with their multitudes of people. ”

“ The war demonstrated the beginnings of what air power meant, though in November, 1918, it was still in its infancy. Before many years the ability to make war successfully, or even at all, will depend upon air power.
Let us now briefly survey the development of the several duties of aircraft, the evolution of machines and progress in tactics, strategy and the organization of our Air Forces during the war. ”

“ Meanwhile, in an effort to crystallize opinion as to air policy, I had published a book called Air Power for Peace, which was issued early in 1945. Patterned on Mahan’s method, this little book reviewed the history of aviation and appraised the impact of air power upon the war. And though history was still in the making and available only in censored headlines, the conclusions drawn in the book were later supported by the reports of the postwar Strategic Bombing Surveys. ”

“ Only a few of the general public could distinguish between a heavier-than-air powered flying machine and a lighter-than-air gas bag equipped with propellers. Few knew that the problem of powered flight was not to fill a balloon with gas or hot air and float in it, or to glide in a complicated kite against air currents. ”

“ We have aviation because man learned how to utilize the fact that air gives support; we have wireless telegraphy, and we will have the wireless transmission of power, because man learned that Nature has her own perfect system of carrying electrical currents when they are properly delivered to her, without any cumbersome system of wires; we have the Tesla turbine because its inventor found out that Nature gave steam, gas, water, and even air, certain properties that are intangible, and yet stronger far than mere brute force ”

“ If he is well aloft, with plenty of air space beneath him, and particularly if he has a machine that is inherently stable, he has little to fear from the wind; save, perhaps, should his engine fail him, or should he find—as has been the case in war flying—that the force of the wind, blowing heavily against him, and reducing the speed of his machine, has prevented him from regaining his own lines before his petrol has become exhausted. The modern aeroplane, when its engine-power is ample, and it is at a suitable altitude, can wage battle successfully even with a gale. ”

“ At a time when new enterprises had been almost interdicted by the unfavorable economic climate and they had been singled out for attack, they had still gone on, with youthful self-reliance, with rugged independence, and a competitive spirit, to exploit the freedom of their homeland and create a new art.
And out of my swing around the circuit, I reached clear conclusions with respect to my own problem, aircraft power plants. I had heard nothing to shake my convictions as to the superiority of air-cooled radials. ”

“ Aside from that, in actual warfare airplanes have to operate at extreme heights, where the air is so rare that oxygen must be supplied to the aviators, and it was difficult to provide this supply of oxygen with the radio helmet tightly strapped to the head of the operator. But after considerable experiment, this difficulty was overcome and also that of the varying pressures on the ears.
Another great difficulty was to obtain a steady supply of power on the airplane to operate the transmitting-apparatus. ”

“ When an inventor has fitted an engine to an aircraft, means must be devised for using its power to drive the machine through the air; and to make the wings flap like those of a bird, has been found so complicated, owing to the mechanism necessary to imitate natural movements, that much of [Pg 14] the power is wasted. ”

“ And so it is quite within the possibilities that a multitude of uses may be found for the employment of liquid air as a motive power, in which its condensed form, its transportability or other properties will give it precedence over steam or electricity. It has been suggested, for example, that liquefied gas would seem to afford the motive power par excellence for the flying-machine, once that elusive vehicle is well in harness, since one of the greatest problems here is to reduce the weight of the motor apparatus. ”

“ As I told you before when we were talking of the wireless transmission of power, the mechanism will be a development of the principle on which my turbine is constructed. It will be so tremendously powerful that it will make a veritable rope of air above the great machine to hold it at any altitude the navigators may choose, and also a rope of air in front or in the rear to send it forward or backward at almost any speed desired. ”

“ In these days, when aeronauts attempt to reach an exceptionally lofty altitude, they invariably provide themselves with a cylinder of oxygen gas to meet the special emergencies of the situation, so that when regions of such attenuated air are reached that the action of heart and lungs becomes seriously affected, it is still within their power to inhale the life-giving gas which affords the greatest available restorative to their energies. ”

“ As winter was already well set in, we should have postponed our trials to a more favourable season, but for the fact that we were determined, before returning home, to know whether the machine possessed sufficient power to fly, sufficient strength to withstand the shock of landings, and sufficient capacity of control to make flight safe in boisterous winds, as well as in calm air. ”

“ It demonstrated that a flying-machine carrying its own propelling power could be made powerful and light enough to lift itself in the air; that an aeroplane will lift much more than a balloon of equal weight; and that a well-made screw-propeller will grip the air sufficiently to propel a machine at a high rate of speed. ”

“ At the pressure proposed (forty-five pounds) the air-driven engines will indicate from thirty to sixty-five per cent of the power developed at the main engines, according to the mode of using the compressed air. ”

“ Once able to obtain the power of a ten-horse engine, with a weight, including machinery, of less than one ton, one might fly all over the world, and, by taking advantage of the air currents, a knowledge of which 330will soon be gained, fly at a speed of fifty or even one hundred miles an hour. The recent discovery of the immense power of a gas which it is possible to generate from benzine without the use of fuel, has made the air as available for the purposes of rapid transit by man as the ocean or the land. ”

“ To go forward, the air must be driven aft. Knowing the speed proposed, our table will give us at once the resistance for each square foot; and knowing the size or bulk of our machine, we can readily estimate the power required.
The management of the wind unquestionably will be a very important factor in the construction of a flying-machine; indeed, it may be considered the most troublesome part of all. Properly handled, the wind might be made a useful servant, otherwise a dangerous master.
The only plan that suggests itself is through the use of an inclined plane. ”

“ Do you know for how long a voyage the best aeroplane types can be provisioned with power? There's not an air-ship of any kind that can go more than two weeks at the very uttermost without touching solid earth, and then it must be mighty sparing of its power. ”

“ Wind Pressure a Necessity.
While all this is true, the fact remains that wind pressure, up to a certain stage, is an absolute necessity in aerial navigation. The atmosphere itself has very little real supporting power, especially if inactive. If a body heavier than air is to remain afloat it must move rapidly while in suspension. ”

“ The ratio of weight to power would prevent a forty-ton aëroplane—which is approximately the largest heavier-than-air craft that at present might be constructed and effectively handled—from remaining aloft in still air for longer than twenty-five hours, carrying a load of passengers and mails of about five tons at an air speed of, say, eighty-five miles an hour. Its maximum air distance, without landing to replenish the fuel supply, would thus be two thousand, one hundred and twenty-five miles. ”

“ Coming next to the wind motors, these possess one very great merit: they utilize a motive power that is always present as long as the plane is in motion through the air. 147On the other hand, the process of using the main propeller of the plane to pull another smaller propeller through the air appears a roundabout way to utilize the driving power of the airplane engine. ”

“ Thus this contrivance, by a small expenditure of fuel, enables the air to act expansively without injurious cooling, and even reduces the consumption of compressed air to an extent which compensates for part of the loss of power arising from the preliminary expansion which the air experiences before its admission into the engine. ”

“ The aircraft, because it is solar-powered, eliminates expensive fuel costs. In the future, researchers envision that the airplane will be able to ‘loiter’ in the air over the region of interest for days or weeks at a time, or until weather conditions are best for data gathering. ”

“ Curt explained. “After you learn the parts of the airplane, the way each one works, what it is for, and so on, and how they are put together, you have to study about airplane engines—the principle of the internal combustion engine and what all the parts are for and how they work. There has to be study of—let’s see—oh, yes!—aerodynamics—how a ship flies, and why, and what different air currents do, and how to know their effects. ”

“ We have now seen that air is a gas, that it exercises pressure, that it possesses weight. We know it can be applied to many useful purposes, and that the air machines and inventions—such as the air-pump and the “Pneumatic Despatch”—are in daily use in our laboratories, our steam engines, our condensed milk manufactories, and in many other industries, and for our social benefit. Compressed air is a powerful motor for boring machinery in tunnels where steam cannot be used, even if water could be supplied, for smoke or fire would suffocate the workers. ”

“ Every year lighter and lighter gas-engines are being made, and this means that the surplus carrying power of the aeroplane can be increased. Fuel can be carried for flights of greater and greater distances, and rapid increases of speed can be attained. ”

“ Fig. 63.—Film winding and exposing mechanism in German film camera.
Variable speed is arranged for in any one of several ways. For peace-time uses a turbine attached to the side of the plane is simple and positive, and, provided it is made of sufficient size—which is not the case with the one shown in the Figure—will give adequate speed regulation upon varying the aperture through which the air enters. The Venturi tube may be carried upon the same mount, or a small rotary pump can be attached on the same shaft. ”

“ Happily the experience of those days, though purchased at the cost of many lives, has taught makers of air-craft to design their machines on more trustworthy lines. Pilots, too, have made a scientific study of air eddies, gusts, and so on, and the danger of flying in a strong or gusty wind is comparatively small. ”

“ The flying machine which will navigate successfully in a perfectly quiet atmosphere may be unseaworthy, or rather, unairworthy, when a wind springs up, or the shifting of the wind may spoil all the air pilot’s plans. To add to his troubles, the aviator must move among air currents which change and change again in a moment’s time. As we study the difficulties of air navigation we will appreciate, more than ever, the wonderful patience, skill, and daring of the successful aviators.
The action of the air currents had first to be carefully studied before flight became possible. ”

“ The importance of this matter entitles it to rank almost as a National obligation; for the country in which facilities are given for the proper theoretical and experimental study of flight will inevitably find itself in the best position to take the lead in its application and practical development. That this must be considered a vital question from a National point of view is beyond dispute; under the conditions of the near future the command of the air must become at least as essential to the safety of the Empire as will be our continued supremacy on the high seas. ”

“ The ‘Bodensee’ German passenger balloon.
In considering the possibility of a commercial dirigible service, it is necessary always to bear in mind373 the disadvantages of first cost and upkeep as compared with the aeroplane. The building of a modern rigid is an exceedingly costly undertaking, and the provision of an efficient supply of hydrogen gas to keep its compartments filled is a very large item in upkeep of which the heavier-than-air machine goes free. ”