  Every Boy's Every Boy's Mechanical Library By J. S. ZERBE, M.E. Price, per volume, 60 cents, Net. Postage extra. AUTOMOBILES This is a subject in which every boy is interested. While few mechanics have the opportunity to actually build an automobile, it is the knowledge which he must acquire about every particular device used, that enables him to repair and put such machines in order. The aim of this book is to make the boy acquainted with each element, so that he may understand why it is made in that special way, and what the advantages and disadvantages are of the different types. To that end each structure is shown in detail as much as possible, and the parts separated so as to give a clear insight of the different functions, all of which are explained by original drawings specially prepared to aid the reader. MOTORS To the boy who wants to know the theory and the practical working of the different kinds of motors, told in language which he can understand, and illustrated with clear and explicit drawings, this volume will be appreciated. It sets forth the groundwork on which power is based, and includes steam generators, and engines, as well as wind and water motors, and thoroughly describes the Internal Combustion Engine. It has special chapters on Carbureters, Ignition, and Electrical systems used, and particularly points out the parts and fittings required with all devices needed in enginery. It explains the value of compounding, condensing, pre-heating and expansion, together with the methods used to calculate and transmit power. Numerous original illustrations. AEROPLANES This work is not intended to set forth the exploits of aviators nor to give a history of the Art. It is a book of instructions intended to point out the theories of flying, as given by the pioneers, the practical application of power to the various flying structures; how they are built; the different methods of controlling them; the advantages and disadvantages of the types now in use; and suggestions as to the directions in which improvements are required. It distinctly points out wherein mechanical flight differs from bird flight, and what are the relations of shape, form, size and weight. It treats of kites, gliders and model aeroplanes, and has an interesting chapter on the aeroplane and its uses in the great war. All the illustrations have been specially prepared for the work. CUPPLES & LEON CO., Publishers, NEW YORK Every Boy's Mechanical Library MOTORS
J. S. ZERBE, M.E.
Copyright, 1915, by
LIST OF ILLUSTRATIONS The motor is the great dominating factor in the world of industry. Every wheel and spindle; every shaft and loom, and every piece of mechanism which has motion, derives it from some sort of motor. The term motor has a wider significance than any other word. A steam engine is a motor, and so, also, is a dynamo, a water wheel or a wind mill. It would be just as descriptive to call a wind mill a wind motor, or a steam engine a steam motor, as to adhere to the old terms; and, on the other hand, since it would be out of place to call a dynamo or a wind mill an engine, the word motor seems best adapted to express the meaning of every type of mechanism which transforms energy into motion. In considering the subject I shall proceed on the theory that the boy knows nothing whatsoever of the subject, nor the terms used to designate the various phases, subjects and elements. It must be elementary in its character, and wholly devoid of technical terms or sentences. While it is necessary to give information in a book of this character, on the methods for figuring out power, it must be done without resorting to the formulas usually employed in engineering works, as they are of such a nature that the boy must have some knowledge of the higher mathematics to follow out the calculations employed. Indeed, every phase should be brought within the mental view of the boy, and to do this may occasionally necessitate what might appear to be long drawn out explanations, all of which, it is hoped, will be the means of more clearly presenting the subject. The opening chapters, which treat of the fundamentals, will be as nearly complete as possible, and thus lay a foundation for the work we shall be called upon to perform, when we treat of the structures of the different parts and devices in the various types of motors. The object is to explain power in its various phases, how derived, and the manner in which advantage is taken of the elements, and substances with which we are brought into contact. The reasons for each step are plainly set forth with the view of teaching the boy what power means, rather than to instruct him how to make some particular part of the machinery. The Inquisitive Trait.—My experience has impressed me with the universality of one trait in boys, namely, that of inquisitiveness. Put a machine before a boy and allow him to dissect it, and his curiosity will prompt him to question the motive for the particular construction of each part of its make-up. The Reasons for Doing Things.—He is interested in knowing the reason why. Every boy has the spirit of the true investigator,—that quality which seeks to go behind or delve down deeply. This is a natural instinct. The Mystery of Mechanism.—If this taste is gratified, and he thereby learns the mystery of the machine, what a wonderful world is opened to him! The value of the lesson will depend, in a large measure, on the things which he has found out for himself. It is that which counts, because he never forgets that which he has dug out and discovered. Curiosity Which Prompts Investigation.—I recall a farmer's boy whose curiosity led him to investigate the binding mechanism of a reaper. It was a marvel to him, as it has been to many others. He studied it day after day, and finally, unaided mastered the art. That was something which could not be taken away from him. It was a pleasure to hear him explain its operation to a group of boys, and men, too, in which he used the knot itself to explain how the various fingers and levers coÖperated to perform their functions. It was an open book to him, but there was not one in the group of listeners who could repeat the explanation. The Sum of Knowledge.—It is the self-taught boy who becomes the expert. The great inventors did not depend on explanations. A book of this character has a field of usefulness if it merely sets forth, as far as possible, the sum of useful knowledge which has been gained by others, so as to enable the boy to go forward from that point, and thus gain immensely in time. There is so much that has been developed in the past, with reference to the properties of matter, or concerning the utility of movements, and facts in the realm of weights, measures, and values of elements which he must deal with, that, as he studies the mechanical problems, the book becomes a sort of cyclopedia, more than a work designed to guide him in the building of special engines or motors. The Author. MOTORS AND MOTIVE POWER What makes the wheels turn round? This simple question is asked over and over again. To reply means pages of answers and volumes of explanations. The Water Fall.—Go with me to the little stream I have in mind, and stand on the crest of the hill where we can see the water pouring down over the falls, and watch it whirling away over the rocks below. The world was very, very old, before man thought of using the water of the falls, or the rushing stream below, to grind his corn or to render him other service. Water Moves in One Direction Only.—What the original man saw was a body of water moving in one direction only. When he wanted to grind corn he put it in the hollow of a rock, and then beat it with a stone, which he raised by hand at each stroke. In doing so two motions were required in opposite directions, and it took thousands of years for him to learn that the water rushing along in one direction, could be made to move the stone, or the pestle of his primitive grinding mill, in two directions. It took him thousands of years more to learn another thing, namely, that the water could be made to turn the stone round, or rotate it, and thus cause one stone, when turning on another, to crush and grind the grain between them. Now, as we go along with the unfolding of the great question of motors, we must learn something of the terms which are employed, to designate the different things we shall deal with, and we ought to have some understanding of the sources of power. What Is Energy?—The running, as well as the falling water represent energy. This is something which is in the thing, the element, or the substance itself. It does not come from without. It is not imparted to it by anything. Stored or Potential Energy.—At the top of the falls, look at that immense rock. It has been there for centuries. It, also, has energy. There is stored within it a tremendous power. You smile! Yes, the power has been there for ages, and now by a slight push it is sent crashing down the precipice. The power developed by that fall was thousands of times greater than the push which dislodged it. But, you say, the push against the stone represented an external force, and such being the case, why do you say that power is within the thing itself? The answer is, that not one iota of the power required to push the stone off its seat was added to the power of the stone when it fell. Furthermore, the power required to dislodge the stone came from within me, and not from any outside source. Here we have two different forms of energy, but both represent a moving force. The power derived from them is the same. Kinetic Energy.—The energy of the falling water or stone is called Kinetic energy. In both cases the power developed came from within themselves and not from any exterior source. The difference between Potential and Kinetic Energy is therefore that Potential Energy represents the capacity to do work, while Kinetic Energy is the actual performance of work. Friction.—In every form of energy there is always something to detract from it or take away a portion of its full force, called friction. When a shaft turns, it rubs against the bearings, and more or less power is absorbed. When a wheel travels over the ground friction is ever present. The dislodging of the stone required ten pounds of energy, but a thousand pounds was developed by the fall. The water rushing along its rocky bed has friction all along its path. Resistance.—This friction is a resistance to the movement of a body, and is ever present. It is necessary to go back and examine the reason for this. As long as the stone was poised at the top of the precipice it had latent or potential energy, which might be termed power at rest. When it fell it had power in motion. In both cases gravity acted upon the stone, and in like manner on the water pouring over the falls. Inertia.—Inertia or momentum is inherent in all things and represents the resistance of any body or matter, to change its condition of rest or standing still into motion, and is then called Inertia of Rest, or the resistance it offers to increase or decrease its speed when moving, and is then called Inertia of Motion. Inertia or momentum is composed by the weight of the body and its speed and is measured by multiplying its weight by its speed. The law is, that when a body is at rest it will remain at rest eternally, and when in motion it will continue in motion forever, unless acted on by some external force or resistance. An object lying on the ground has the frictional resistance of the earth to prevent its moving. When the object is flying through space it meets the air and has also the downward pull of gravity, which seek to bring it to rest. These resisting forces are less in water, and still less in gases, and there is, therefore, a state of mobility in them which is not found in solids. Internal and External Resistance.—All bodies are subject to internal, as well as external resistance. The stone on the cliff resisted the movement to push it over. Weight was the resisting internal force, but when the stone was moving through the air, the friction with the air created external resistance. Energy Indestructible.—There is another thing which should be understood, and that is the absolute indestructibility of energy. Matter may be changed in form, or in the direction of its motion, by the change of kinetic into potential energy, or vice versa, but the sum total of the energy in the world is unalterable or constant. The tremendous power developed by the stone when it plunged through space and struck the rocks below, developed a heat at its impact. Thus the moving force which was a motion in one direction was converted into another form of energy, heat. The expansion of the material exposed to the heat also represented energy. When powder explodes and absolutely changes the form of the substance, its volume of expansion, if it should be retained within a vessel, would perform a certain amount of work, and the energy is thus transferred from one form to another without ceasing. Wind Power.—Primitive man also saw and felt the winds. He noted its tremendous power, but he could not see how a force moving in one direction only could be utilized by him. Rectilinear Motion.—This movement of the wind in one direction, like the water flowing along the bed of the river, is called rectilinear motion. It required invention to convert rectilinear into circular motion. Oscillating Motion.—When he threshed his grain and winnowed it by shaking it to and fro, to rid it of the chaff, the idea of using the wind to produce an oscillating motion did not occur to him. After circular motion was produced, the crank was formed and thus the oscillating movement was brought about. Movements in Nature.—All movements in nature are simple ones, of which the following are illustrations: 1. Rectilinear, which, as stated, means in a straight line. 2. Circular, like the motion of the earth on its axis, once every twenty-four hours. 3. Oscillatory, like a to and fro movement, the swaying branches of trees, or the swinging of a pendulum. How Man Utilizes the Various Movements.—What man has done is to utilize the great natural forces in nature in such a way as to produce these movements at will, in either direction, with greater or less speed, at regular or irregular intervals, and at such amplitudes as are required to perform the necessary work. Kinds of Potential Energy.—Now, materials have within themselves potential energy of various kinds. Thus, powder, if ignited, will burn, and in burning will expand, or explode, as we term it. This is true also of oils and gases. The expansion pressure produced from such substances depends on the speed at which they will burn, and in so confining the burning substances that a great pressure is produced. The Power in Heat.—The pressure of all such substances against the confining medium depends on heat. Any gas which has 523 degrees of heat imparted to it will expand double its volume. If one cubic inch of water is converted into steam the latter will occupy one cubic foot of space under atmospheric pressure,—that is, it will expand over 1700 times. Energy in Steam.—If the steam thus generated is now subjected to 523 degrees of heat additional, it will occupy over 3400 cubic inches of space. It will thus be seen why steam, gas, and gasoline engines are called heat engines, or heat motors. Energy From the Sun.—Many attempts have been made to utilize the heat of the sun, to turn machinery, but the difficulty has been to secure sufficient heat, on the one hand, and on the other to properly cool down the heated gases, so that the various liquid and solid fuels are required to make the heat transformations. Power From Water.—In the use of water two forms are available, one where the water is moving along or falling in a constant open stream; and the other where the flowing water is confined and where its flow can be regulated and controlled. The latter is more available for two reasons: First: Economy in the use of water. Second: Ability to control the speed or movement of the motor. With running or falling streams a large surface is required, and the wheels turn slowly. Two well-recognized forms of wheels have been employed, one called the undershot, or breast wheel, shown in Fig. 1, and the other the overshot, illustrated in Fig. 2. |
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