James Slough Zerbe

“ ABNORMAL FLYING OF NO VALUE.—It would be too broad an assertion to say that it has absolutely no value, because everything has its use in a certain sense, but if we are to judge from the progress of inventions in other directions, such exhibitions will not improve the art of building the device, or make a fool-proof machine.
Indeed, it is the very thing which serves as a deterrent, rather than an incentive. If machines can be handled in such a remarkable manner, they must be, indeed, perfect! Nothing more is needed! They must represent the highest structural type of mechanism! ”

“ MECHANISM DEVOID OF INTELLIGENCE.—The great error, however, in seeking to copy nature's form in a flying machine is, that we cannot invest the mechanism with that which the bird has, namely, a guiding intelligence to direct it instinctively, as the flying creature does.
A MACHINE MUST HAVE A SUBSTITUTE FOR INTELLIGENCE. —Such being the case it must be endowed with something which is a substitute. A bird is a supple, pliant organism; a machine is a rigid structure. One is capable of being directed by a mind which is a part of the thing itself ”

“ On land, man has shown this superiority over matter, and so on the sea. Singularly, the submarines, which go beneath the sea, are very far from that perfected state which have been attained by vessels sailing on the surface; and while the means of transportation on land are arriving at points where the developments are swift and remarkable, the space above the earth has not yet been conquered, but is going through that same period of development which precedes the production of the true form itself. ”

“ CERTAIN CONDITIONS IN FLYING.—In an aeroplane conditions are reversed. Shutting off the fuel supply and applying the brakes only bring on the main difficulty. He must learn to stop the machine after all this is done, and this is the great test of flying. It is not the launching,— the ability to get into the air, but the landing, that gives the pupil his first shock.
Man is so accustomed to the little swirls of air all about him, that he does not appreciate what they mean to a machine which is once free to glide along in the little currents which are so unnoticeable to him as a pedestrian. ”

“ A STONE AS A FLYING MACHINE.—When a stone is propelled through space, shape is of no importance. If it has rough and jagged sides its speed or its distance may be limited, as compared with a perfectly rounded form. It may be made in such a shape as will offer less resistance to the air in flight, but its actual propulsion through space does not depend on how it is made, but on the power which propelled it, and such a missile is a true heavier-than-air machine. ”

“ It is not enough to know that a lever or a wheel when moved a certain way will move a plane a definite direction. He should learn to know instinctively, how FAR a movement to make to get a certain result in the plane itself, and under running conditions, as well.
Suppose we have an automobile, running at the rate of ten miles an hour, and the chauffeur turns the steering wheel ten degrees. He can do so with perfect safety; but let the machine be going forty miles an hour, and turn the wheel ten degrees, and it may mean an accident. ”

“ MAN DOES NOT COPY NATURE.—Look about you, and see how many mechanical devices follow the forms laid down by nature, or in what respect man uses the types which nature provides in devising the many inventions which ingenuity has brought forth.
PRINCIPLES ESSENTIAL, NOT FORMS.—It is essential that man shall follow nature's laws. He cannot evade the principles on which the operations of mechanism depend; but in doing so he has, in nearly every instance, departed from the form which nature has suggested, and made the machine irrespective of nature's type. ”

“ It was not satisfying enough to know that man was copying nature. It was more important to know why nature originated that type of formation, because, it is obvious, that if such structures are universal in the kingdom of flying creatures, there must be some underlying principle which accounted for it.
It is not the aim of the book to teach the art of flying, but rather to show how and why the present machines fly. The making and the using are separate and independent functions, and of the two the more important is the knowledge how to make a correct machine. ”

“ If a ball is thrown through the air, its dynamic force is measured by its impact. So with light, and heat. In the space between the planets it is very cold. The sunlight, or the rays from the sun are there, just the same as on the earth.
Unless the rays come into contact with something, they produce no effect. When the beams from the sun come into contact with the atmosphere a dynamic force is exerted, just the same as when the ball struck an object. When the rays reach the earth, reflection takes place, and these reflected beams act on the air under different conditions. ”

“ Unquestionably, a support can be obtained by beating on the air but to do so it is necessary to adopt the principle employed by nature to secure an upward propulsion. As pointed out elsewhere, it cannot be the concaved type of wing, or its shape, or relative size to the weight it must carry.
As nature has furnished such a variety of data on these points, all varying to such a remarkable degree, we must look elsewhere to find the secret. Only one other direction offers any opportunity, and that is in the individual wing movement. ”

“ When in motion, therefore, while the lift, so far as its mass is concerned, does not change, the drift does decrease, or the forward pull is less than when at 45 degrees, and the decrease is less and less until the plane assumes a horizontal position, where it is absolutely nil, if we do not consider head resistance.
TABLES OF LIFT AND DRIFT.—All tables of Lift and Drift consider only the air pressures. They do not take into account the fact that momentum takes an important part in the translation of an object, like a flying machine. ”

“ The art is still very young; so much is done which arises from speculation and theories; too much dependence is placed on the aviator; the desire in the present condition of the art is to exploit the man and not the machine; dare-devil exhibitions seem to be more important than perfecting the mechanism; and such useless attempts as flying upside down, looping the loop, and characteristic displays of that kind, are of no value to the art. ”

“ SPEED AND SURFACE.—Birds which poise in the air, like the humming bird, do so because they beat their wings with great rapidity. Those which soar, as stated, can do so only by moving through the atmosphere rapidly, or by having a large wing spread relative to the weight. It will thus be seen that speed and surface become the controlling factors in flight, and that while the latter may be entirely eliminated from the problem, speed is absolutely necessary under any and all conditions. ”

“ If there should be no material substance, like air, then the only way in which a heavier-than-air machine could ever fly, would be by propelling it through space, like the ball was thrown, or by some sort of impulse or reaction mechanism on the air-ship itself. It could get no support from the atmosphere.
LIGHT MACHINES UNSTABLE.—Gradually the question of weight is solving itself. Aviators are beginning to realize that momentum is a wonderful property, and a most important element in flying. The safest machines are those which have weight. ”

“ The high center of gravity in all machines makes the weight useless to counterbalance the rising end or to hold up the depressed wing.
All aviators agree that these unequal areas of density extend over small spaces, and it is, therefore, obvious that a machine which is of such a structure that it moves through the air broadside on, will be more liable to meet these inequalities than one which is narrow and does not take in such a wide path. ”

“ The foregoing remarks are made in order to impress on the novice that theories do not make flying machines, and that speculations, or analogies of what we see all about us, will not make an aviator. A flying machine is a question of dynamics, just as surely as the action of the sun on the air, and the movements of the currents, and the knowledge of applying those forces in the flying machine makes the aviator. ”

“ If the rotative speed of the earth should be retarded, all objects on the earth would be increased in weight, and if the motion should be accelerated objects would become lighter, and if sufficient speed should be attained all matter would fly off the surface, just as dirt dies off the rim of a wheel at certain speeds.
A TANGENT.—When an object is thrown horizontally the line of flight is tangential to the earth, or at right angles to the force of gravity. Such a course in a flying machine finds less resistance than if it should be projected upwardly, or directly opposite the centripetal pull. ”

“ The engine is set in motion, and now, for the first time a new sensation takes possession of you, for the reason that you are cut off from communication with those around you as absolutely as though they were a hundred miles away. ”

“ OBSERVATIONS WHILE IN FLIGHT.—If there are any bad spots, or trees, or dangerous places, they should be spotted out, and mentally noted before attempting to make any flight. When in the air during these trials you will have enough to occupy your mind without looking out for the hazardous regions at the same time.
Make the first turns in a still air. If you should attempt to make the first attempts with a wind blowing you will find a compound motion that will very likely give you a surprise. In making the first turn you will get the sensation of trying to fly against a wind. ”

“ First, when flying with the wind the speed must be greater than when flying against it.
By greater speed is meant relative to the earth. If the machine has a speed of thirty miles an hour, in still air, the speed would be forty miles an hour going with the wind, but only twenty miles against the wind. Second, the banking of the planes against the air is more effective when going into the wind than when traveling with it, and, therefore, the speed at which you contact with the earth is lessened to such an extent that a comparatively easy landing is effected. ”

“ Thus, light, heat and electricity are the same, the manifestations being unlike only because they have different modes of motion.
Everything in nature manifests itself by motion. It is the only way in which nature acts. Every transformation from one thing to another, is by way of a movement which is characteristic in itself. ”

“ WHAT AMOUNT OF POWER IS NECESSARY.—In the consideration of any power plant certain calculations must be made to determine what is required. A horse power means the lifting of a certain weight, a definite distance, within a specified time.
If the weight of the vehicle, with its load, are known, and its resistance, or the character of the roadway is understood, it is a comparatively easy matter to calculate just how much power must be exerted to overcome that resistance, and move the vehicle a certain speed. ”

“ The only thing in the Wright machine which in any way resembles the bird's wing, is the rounded end of the planes, and judging from other machines, which have square ends, this slight similarity does not contribute to its stability or otherwise help the structure. ”

“ The soaring bird travels at great speeds, and this in itself should be sufficient to enable us to cease wondering, when it is remembered that swift translation decreases weight, so that this factor does not, under those conditions, operate against flight.
MUSCULAR ENERGY EXERTED BY SOARING BIRDS. —It is not conceivable that the mere will of the bird would impel it forwardly, without it exerted some muscular energy to keep up its speed. The distance at which the bird performs this wonderful evolution is at such heights from the observer that the eye cannot detect a movement. ”

“ In such a case it is far safer to go up into the air than to make the land, because, unless the utmost care is exercised, one of the wing tips will strike the earth and wreck the machine.
Another danger point is losing headway, as the earth is neared, due to flying at too flat an angle, or against a wind that happens to be blowing particularly hard at the landing place. If the motor is still going this does not make so much difference, but in a volplane it means that the descent must be so steep, at the last moment of flight, that the chassis is liable to be crushed by the impact. ”

“ When the stroke of the wing is downwardly the rear margin is higher than the front edge, so that the downward beat not only raises the body upwardly, but also propels it forwardly.
THE WING MOVEMENT.—The moment the wing starts to swing upwardly the rear end is depressed, and now, as the bird is moving forwardly, the wing surface has a positive angle of incidence, and as the wing rises while the forward motion is taking place, there is no resistance which is effective enough to counteract the momentum which has been set up. ”

“ CHAPTER IV FORE AND AFT CONTROL THERE is no phase of the art of flying more important than the fore and aft control of an airship. Lateral stability is secondary to this feature, for reasons which will appear as we develop the subject.
THE BIRD TYPE OF FORE AND AFT CONTROL.— Every aeroplane follows the type set by nature in the particular that the body is caused to oscillate on a vertical fore and aft plane while in flight. The bird has one important advantage, however, in structure. Its wing has a flexure at the joint, so that its body can so oscillate independently of the angle of the wings. ”

“ The foregoing is the substance of the law, namely, that all bodies attract all other bodies with a force directly in proportion to their mass, and inversely as the square of their distance from one another. ”

“ If projected through space, a certain mass would move so as to produce momentum, which would be equal at all places on the earth's surface, or at any altitude.
Gravity has been called weight, and weight gravity. The real difference is plain if gravity is considered as the attraction of mass for mass. Gravity is generally known and considered as a force which seeks to draw things to the earth. ”

“ THE LAW OF GRAVITY.—As the effort to fly may be considered in the light of a struggle to avoid the laws of nature with respect to matter, it may be well to consider this great force as a fitting prelude to the study of our subject. ”

“ If the power is transferred from the cylinder to the engine shaft where it could deliver its output without the use of a propeller, it would not be so important to consider the matter of vibration; but the propeller, if permitted to vibrate, or dance about, absorbs a vast amount of energy, while at the same time cutting down its effective pull.
Aside from this it is dangerous to permit the slightest displacement while the engine is running. Any looseness is sure to grow worse, instead of better, and many accidents have been registered by bolts which have come loose from excessive vibration. ”

“ GRAVITY AS POWER.—Indeed, the very act of the ball gradually moving toward the earth, by the force of gravity, is an illustration of a power within the object itself. Long after Galileo firmly established the law of falling bodies it began to dawn on scientists that weight is force. ”

“ When, therefore, a rapidly-moving machine passes through an atmosphere so disturbed, the surfaces of the planes strike a mass of air moving, we may say, first toward the plane, and the next instant the current is reversed, and the machine drops, because its support is temporarily gone, and the aviator experiences the sensation of going into a "hole." ”