CHAPTER IV
LEARNING TO FLY
EARLY METHODS—DEVELOPMENT OF SCHOOLS—STUDYING STRUCTURE OF PLANES, MOTORS, THEORY OF FLIGHT, AERODYNAMICS, MAP READING—FRENCH SYSTEM—GOSPORT SYSTEM
Fromthe time of the first flight of the Wright brothers in 1903 to the breaking out of the Great War in July, 1914, the art of flying an aeroplane was not taught systematically either in private or military schools, primarily because flying in a heavier-than-air machine was regarded by civilians as a very dangerous sport and by military authorities as hardly more than a dubious scout for locating troop or train movements. For that reason very few civilians were induced to take up aviation except a few of the more daring sportsmen. Consequently, civilian flying on a large scale did not flourish.
It is true, however, that several small schools attached to manufacturing plants did attempt to teach the rudiments of flight and aircraft construction. These schools did not prosper because only a few pupils who wished to give exhibition flights attended, and the art of flying and aircraft development suffered.
In England several schools were started with indifferent success for the same reason as obtained inAmerica, and in France and Germany, aside from a few aviators who were striving for new world’s records, most of the flying training was in the army. Therefore most of the great fliers, like the Wrights, Beachy, Martin, Curtiss, Farman, Bleriot, Garros, Vedrines, Graham-White, Sopwith, A. V. Roe—to mention only a very few—learned to fly themselves. For that reason the toll of lives taken in flying was high. Nevertheless, that did not stop these daring fliers from stunting and exploring all the aerial manœuvres possible with a heavier-than-air machine. As a result Pegout looped the loop; Ruth Law flew at night; Bleriot crossed the channel; Garros the Mediterranean Sea; Vedrines flew from Paris via Constantinople to Cairo; and in July, 1914, Heinrich Oelerich climbed to 26,246 feet altitude in Germany, and in the same month another German flew for twenty-four hours one minute, without stopping.
Meanwhile France had trained several hundred aviators for her army and Germany had five or six hundred trained fliers, including those in the Zeppelin service. The United States army had hardly more than fifty fliers when the Mexican trouble broke out, and only half a dozen aeroplanes to use on the Mexican border.
As soon as the war began and aircraft demonstrated that the side which got control of the air could put out the eyes of the opposing army and that the great struggle might be decided in the air, all the belligerent nations began to train aviators for the war in the air.
France was the first to develop a school of flying, and the French method, with slight variations, was adopted by England and the United States. A description of their method will give a comprehensive conception of the training necessary for a military flier in the war.
Early in the war most of the army, navy, and private aviation schools of the United States adopted the penguin system of learning to fly. That method, invented by the French, consisted of using as a training-machine an aeroplane that had so small a wing spread or so weak a motor that it merely hopped five or six feet off the ground when the motor was wide open. The small wing spread caused it to zigzag along the ground like a drunken man. For those reasons, perhaps, it was named after the penguin, which does not remain long on the ground or in the air and which has an irregular gait.
The first step in learning to fly consists in studying the structure of the aeroplane and of the aeronautical engine, and aerodynamics, or the science of the forces that aid or hinder the flight of heavier-than-air machines. During the last half-dozen years many of the manufacturers of aircraft maintained schools in order to encourage men to learn the art of flying, and have given their pupils the chance to study at first hand the designing, the building, and the assembling of aeroplanes and hydroplanes. That has given the pupils a thorough knowledge of every detail of the aircraft—an invaluable asset to an aviator who has beencompelled to make a forced landing far from a repair-shop. In the “ground” schools conducted by the United States Government for instructing aviation officers at the various institutions, like Cornell, Massachusetts Institute of Technology, and Princeton, a great deal of time was devoted to assembling aeroplanes.
Most of the manufacturers of aircraft in this country do not make the motors used to propel their aeroplanes. The aeronautical motor is one of the most difficult machines to build successfully. A motor that runs as smoothly as a watch on the ground may hesitate and sputter at an altitude of a thousand feet, and at three thousand feet may stop altogether. Engineers say that that is because the change in temperature and in atmospheric pressure causes a difference in carburization. All these things the prospective flier had to learn as well as the reasons for the same.
Contrary to the general notion, the construction of the aeronautical motor differs radically from that of the automobile engine. In point of weight the difference is marked. Seldom is any stipulation made that limits the weight of the automobile motor in proportion to the amount of horse-power; a few pounds more or less is not an important consideration in a pleasure-car or a motor-truck. But in an aeroplane every ounce of superfluous weight must be eliminated from the engine, which must nevertheless be strong enough to withstand the most violent strain.
The aeroplane motor is subject to far greater strainsthan the automobile motor is. Except during a race, one rarely runs the engine of an automobile at its maximum speed; the aeroplane motor, on the contrary, usually runs at full speed from the moment the aeroplane starts until the motor is shut off and begins to volplane down to the earth. It is true that you can regulate the aeroplane engine by the throttle to run from as low as three hundred revolutions a minute to as high as sixteen hundred; but except when testing the motor there is rarely any reason for slowing it up while in the air. The load that the propeller of an aeroplane carries is much less than the load that the shaft of an automobile carries, but, on account of the frail structure of the plane, the vibration is much more violent. A battle plane seldom weighs more than two thousand pounds, and a scouting machine of the Nieuport type tips the scales at not more than one thousand pounds.
For these reasons aircraft require special kinds of motors. The V type is so called because the cylinders are set in the form of that letter; the rotary motor has the cylinders arranged in a circle like the spokes of a wheel, and it revolves on its shaft like the propeller. The rotary motor is used in scouting machines because it is light. The revolving engine also revolves on its shaft, but it has a great many more cylinders arranged side by side like the cylinders of an automobile engine. It is much heavier than the rotary type; it may have as many as thirty-two cylinders.
Of course, a knowledge of the automobile enginewas an aid to the prospective aviator; for, except in the process of cooling and the revolution of the cylinders, the principles of the automobile motor and those of the aeroplane are identical.
At aviation schools the pupils went thoroughly into all those things and supplemented their knowledge by continually mounting and dismounting engines and examining their most intricate parts. The schools also kept on hand large aeroplane models, which the students took apart and put together again. In the classroom the prospective aviators studied the mathematics and the theory of aerodynamics. All this work was very important, for an aeroplane is such a nicely balanced machine that if it is not perfectly constructed mathematically it will not fly safely.
For example, if the tail plane or flat, finlike surface that projects from the sides of the tail of the body, or fuselage, has too much “incidence,” or, in other words, is slanted at too sharp an angle downward, it has a tendency in flight to lift the rear of the machine and to make it dive. A seaplane, when properly constructed, is so evenly balanced that, when the crane that lifts it off the mother ship holds it suspended in the air, the machine is equipoised like a bird with wings spread in flight. If the plane is heavier on one side than on the other, it will, while “banking,” or turning a corner, slide toward the centre of the circle; that sometimes causes a “tail spin,” in which the machine whirls round as if it had been caught in a whirlpool. That is a very difficult situation, for anaviator usually ends in a smash at the bottom of the whirlpool unless the pilot has altitude enough to flatten out his plane before it gets too close to the ground. These things were all taught before the novice went up in the air.
Map reading and air navigation were the next studies in military aviation schools. First, the student learned how to judge the height of hills and the size of towns from different altitudes, so that when flying he could tell what part of the country he was passing over. Many of the schools perched the prospective fliers high in the air in a classroom and spread out a miniature landscape made of dirt and sand on a map beneath them so they could get practice in perspective.
Of course, when an aviator is lost in the fog or above the clouds he needs to use all the instruments on board to find his position. For that purpose drift instruments are mounted on aircraft; those tell how much the air-currents, which have the same effect on aircraft as the tide has on a boat, have driven him off his course. A compass indicates the direction in which he is travelling, and other instruments show him whether his machine is climbing, diving, or “banking”; the aneroid barometer indicates the altitude. It is essential, of course, for the aviator to know how to read those instruments correctly. Without the information they give him, he might not know, if flying at night or in a cloud, that his craft was climbing at a dangerous angle until wrenches or other loose implements began to fall out of the machine.
As the next step in the training the student learns the controls. To do that he runs the “taxi” or “lawn-mower,” as the training-machine is called, up and down the field. The “hopping” of this machine familiarizes him with “getting off” and landing, and with the noise of the propeller. After he has learned to steer his machine in a straight line, he takes longer “hops” until he is thoroughly familiar with the “joy stick” which pulls the elevators or ailerons up or down or operates the rudder.
Soon afterward the student went up with an instructor for a long flight. The purpose of the flight was to get the pupil used to higher altitudes and to the motion of the aeroplane, and to give him a chance to watch his teacher actually running the machine. Strange to relate, many who have felt an uncontrollable desire to jump off high buildings have no such feeling while in an aeroplane. That is because they sit and look out horizontally instead of perpendicularly downward, and because they move at such tremendous speed.
After several trips of that kind, the instructor let the student handle the controls until he could climb, dive, and “bank,” or turn the machine in the air. But the pupil was not permitted to land a machine until near the end of his course; for next to getting out of a tail spin, a dive, or a side slip, landing was the hardest task in flying. Statistics show that more aviators have been killed in making landings than in any other way. Many of the accidents, of course, werecaused by the nature of the ground, for when the engine of the aeroplane stops, the aviator has to volplane or glide down wherever he can.
One of the difficulties of landing is owing to the fact that even training-machines cannot land at a slower speed than thirty-five miles an hour. If the wheels of the aeroplane, when they first touch ground, do not skim over the surface of the field, the machine is liable to “nose in” and turn a somersault. Indeed, that is why the pusher type of training-machine, with the propeller in the rear of the pilot, is being abandoned for the tractor machine, which has the propeller in front. If an accident does occur with a tractor the engine does not “climb your back.” One of the greatest dangers of flying a seaplane is due to the fact that the engine is installed not in the hull but high above the aviators’ heads, upon which it is apt to fall in case of a crash.
The student was next permitted to fly alone. Most machines were so strongly built that accidents were seldom caused by breakage, although, of course, before each flight the aviator and his mechanic critically examined his machine for broken parts. With a reasonable amount of care straight flying by daylight was comparatively safe.
In the French aviation schools, before the military birdman could pass his final examinations, he had to climb twice to an altitude of six thousand feet and spend an hour at a ten-thousand-foot altitude. If he passed that test successfully, he had to fly over atriangular course of one hundred and fifty miles and land at each corner of the triangle.
Before he could fly his machine on the battle-front the French flier had to know how to loop, to fall or dive at such a steep angle that his machine actually dropped through the air for several hundred feet before it flattened out—a tremendous strain on the wings of a machine—to side slip or round a curve with his machine banked at such an angle that it gradually slid toward the centre of the circle, to climb or tail dive at such a pitch that the aircraft actually slips backward tail foremost. Indeed, in the last days of training the student was encouraged to practise all kinds of stunts and tricks, for when an enemy descended on you from the clouds above and was sitting on your tail weaving a wreath of bullets from a machine-gun round you, your only chance of escape was by means of a loop, a dive, a side slip, or a roll.
Another interesting test a pilot had to undergo before he got his license to do battle was to ascend fifteen hundred feet, cut off all power, and volplane down in a spiral to a fixed point. To perform the manœuvre successfully required great skill. All the members of the famous Lafayette Escadrille had to undergo those tests before becoming fighting aviators, and Americans who received their final training in France had to go through the same training.
In our government flying-schools at Mineola in Long Island and the other flying-fields in Texas and other parts of the country, at San Diego in California, thestudents were put to similar tests of skill. In the private civilian schools, however, instructors rarely attempt to teach their pupils more than straight flying. But most aviators agree that every flyer ought to know the “stunts” in order to meet successfully any extraordinary situation that may confront him.
Of course the training for aerial observers, wireless operators, and photographers was very different from that of the pilots. In each case the instruction was peculiar to the science they were to practise, and it had little to do with aviation, only in so far as it was actually affected by flying. The men who took the pictures had to make a study of the science of photography. The same was true of the wireless operator. The observer, however, had to study topography and the use of the machine-gun, and target practice such as characterized the work of the pilot. In different countries this differed with the methods developed there. In England the pilot often shot at toy balloons in the air while chasing them with his machine or at targets on the ground. The same method was employed by the United States. Nearly all the great aces in the war were very clever shots, and Major Bishop attributed most of his success to his skill with the machine-gun.
Finally the Gosport system of training aviators was adopted by the British and the American armies because it permitted the training of tens of thousands of fliers at the same time. The principles taught were the same as those enumerated above. The system,however, reduces the time spent on each operation to the minimum, specifying the number of hours to be spent on each step in the course. Here is a sample of the outline of the training under that system:
STANDARD OF TRAINING
Part 1. Pilots—Flying Wings
1.Ground Instruction.1. Buzzing and Panneau2. Artillery Observation3. Gunnery4. Aerial Navigation5. Engine Running6. Photography7. Bombing and Camera Obscura8. Air Force Knowledge9. Engines and Rigging, Workshops Course10. Drill and P. T.2.Air Tests.1. Flying Instruction2. Formation Flying3. Cross Country4. Reconnaissance5. Photography6. Bombing (Camera Obscura)7. Ring Sights and Camera Gun8. Altitude Test and Cloud Flying9. Aerial Navigation3.Appendices.A Flying InstructionB Formation FlyingC Cross CountryD BombingE WirelessF GunneryG Ring Sights and Camera GunH Aerial NavigationI Photography
1.Ground Instruction.
2.Air Tests.
3.Appendices.
To insure a certain amount of continuous practice the following minimum times will be spent on ground subjects. It must be realized, however, that efficiency, and not time spent, is the ultimate passing standard.
Lectures will be given covering—
(1) All questions on above subjects.(2) Practical wireless covering knowledge useful to a pilot.(3) All ground signals as given on new Artillery Observation card, 40-W.O.-2584.
(1) All questions on above subjects.
(2) Practical wireless covering knowledge useful to a pilot.
(3) All ground signals as given on new Artillery Observation card, 40-W.O.-2584.
Thus every step in the education of the flier was provided for and thus the United States turned out over 10,000 aviators.