Chapter 3
The natural result of training a pupil along those lines is that he graduates rapidly into a good stunting pilot. He realizes that he cannot tempt the devil at three hundred feet and hope to live, but he takes a good altitude, throws his machine upside down, and knows that, given enough air, he must come out. He does come out unless he loses complete control of his mind and body. With fifteen hours of solo flying the pupil has really become a pilot. He is beginning to show that he can control his machine. From then on it is a question of the polishing of the nice points, making his forced landings perfect, not side-slipping a foot on his vertical banks, and coming out of spin so that he always faces the airdrome--all of which distinguish the good pilot from the poor pilot.
IV
SAFETY IN FLYING
The fatalities on the training-fields of every country during the period of training in war, and before and after the war, testify only too surely that flying cannot be absolutely safe. It is no reflection on the future of flying to realize that it has not been safe, and that it can never, perhaps, be made fool-proof. One or two things must be remembered before we become despondent over the future safety of flying.
When the United States entered the war the entire personnel of the Signal Corps numbered one hundred and sixty officers and men. At the time the armistice was signed more than thirty thousand pilots had been trained. They were trained in great numbers under high pressure. We did not have the machines to train them in or the instructors to fly with them. We had not the experience in wholesale training of flying-men, and yet we turned out vast numbers. It was a question of getting the men through their flying and getting them overseas as quickly as possible. We had no adequate methods of inspection of machines, and no laid-out course in flying-training. We had to learn by our own experience, in spite of the fact that England at all times gave unstinted aid.
The wonder is really that we did not have more flying accidents. There were few men in the country who really understood what conditions tended toward a flying accident. There were few who had ever gone into a spin and lived to tell about it. At that time a spinning-nose dive was a manifestation of hard luck--like a German shell. If you once got into it, it was only the matter of waiting for the crash and hoping that the hospital might be able to pull you through.
Toward the end, of course, this situation had been largely overcome, the Gosport system of flying had been tried out, and there was a vast increase in the knowledge of flying among the instructors and pupils. The spin had been conquered, training was on a sound basis, and accidents were being rapidly cut down.
One of the most obvious ways to cut down crashes was by making sure that the pilot was in good condition physically. Flight surgeons assigned to every camp were detailed to make a study of the very delicate relationship between a sick and stale pilot and the crash. It was discovered, for instance, that a man who went up not in the best condition multiplied by many times the ordinary hazards in the air. It became the duty of these surgeons to conduct recreation and exercises so that pilots would always be in good trim.
Flying for an early solo pupil is the greatest mental strain that a man can experience. Every moment the fact that he is up in the air, supported only by wood, wires, and fabric, may be on his mind. He is making desperate efforts to remember everything his instructor has told him since he started his dual. He tries to keep that nose on the horizon, the wings balanced, and the machine flying true. He is in fear of stalling and consequent loss of control. He goes into his turns, hardly knowing whether he is going to come out of them, and noses down for a landing, mentally giving prayer, perhaps, that he will come out all right. He can't possibly remember everything he has been told, but he tries to salvage as much knowledge as possible to make a decent landing.
These experiences tend to bring about two conditions, aerophobia (fear of the air) and brain fatigue, both resulting in complete loss of head on the part of the pilot and inability to react to impulses. Nothing is more likely to produce immediate and fatal aerophobia than the sickening sight from the air of a crash, yellow wings flattened out against the green ground a thousand feet below. A comrade, a tentmate? The pupil looks at his machine, sees the wires throbbing, and watches with wonder the phenomenon of rushing through the air--he may let his imagination dwell too long.
During his first hour's solo a swift stream of hundreds of impulses is borne along the nerve centers to the brain of a pupil. It is like the pounding of heavy seas against a light sea-wall. His brain reels under the repeated shocks and the pupil falls into a detached stupor. He waits while his engine throbs ahead, and lets the machine fly itself. He seems to take no active participation in the operation, and unless he recovers control of his brain and his machine it is a crash. Physicians then have the problem of learning from a dazed and perhaps badly injured man how it happened. He can recall nothing, and seldom knows when he lost control.
These are the things that happened when this country was hastening fliers overseas. As a matter of national necessity it was essential that as many men as possible be put through their dual and solo flying and sent across to the other side. It was better for the country at large to turn out five hundred pilots a month, say, with 5 per cent. of casualties, than one hundred a month with one-half of 1 per cent. or less of accidents. These figures do not represent the actual conditions, but they picture the problem.
Now the civilian who would take up flying has just as much time as he wants to spend in learning to fly. He is paying for his instruction, and he should continue it for perhaps fifteen to twenty hours of dual instruction. He should fly the machine with an instructor in it, and really get accustomed to the feel of the air. He should become sensitive enough so that he can differentiate between the tight, firm touch to a machine flying under complete control and the slack movement of stick and rudder of a plane very nearly out of control. He should recognize these danger signs and know how to correct his flying position.
Dual flying should be continued up to the point where the pupil flies without thinking, when it becomes the natural thing for him to use both stick and rudder to correct a bump, and when he thinks no more of it than riding over a rut in a road. He should be able to tell by ear, when volplaning, whether or not he is maintaining sufficient speed to hold it in the air. He should be acquainted with the principle of spinning, and should have had some experience in taking a machine out of a spin.
The treacherous thing about a spinning-nose dive is that, to come out of it, a pilot must put his stick forward, not hold it back, in spite of the fact that the machine is falling nose first and spinning at the same time. A spin is possible only from a stall, and only when the stick is back and rudder in either direction is given. The position is an easy one to get into from a steep turn. Air resistance against a machine turning becomes greater, it slows down the speed, decreases the lifting power of the planes. The result is that the nose falls slightly. The pilot moves the stick back to lift the nose, and in doing so pulls up his elevators, offering still more resistance to the air, and checking the speed. The effect becomes cumulative; he tries to hold up his machine, and he has stalled. In a last effort to check the spin he kicks on the rudder, and the thing is done.
The rudder and elevators have formed a pocket in the tail plane, which is like the spoon on a trolling-hook. The pocket is off-center and the air rushes into it as the machine topples over and plunges down. It imparts a twisting motion, which in a turn or two develops into a throbbing spin. Picture the pilot, trying to lift the nose of his machine by holding his stick well back and wondering why the nose does not come up. The pathetic thing is that so many hundred men have thought their salvation was to hold the stick back.
The only possible thing to do in this case is to break the pocket. Put the stick forward to neutral, or even farther if need be, and opposite rudder. The machine will come out in three-quarters of a turn with practice, into a straight-nose dive. Then ease the stick back, and this time the nose comes up and the machine flies on its course. Instructors who have taught their pupils this before they let them go solo have saved many, many lives.
It is reasonable to say that there are no fatal accidents except those from a spin, but, like all general statements, that is open to contradiction. A nose-high side-slip may be fatal, but generally the pilot pulls himself out of it. There may have been men killed in landing accidents, but one seldom hears of them. Men have been killed trying to loop off the ground, and Vernon Castle was killed doing an Immelmann turn at fifty feet to avoid another machine. These are the exceptions. The common or garden variety of accident is from a spin. The spin once conquered, the air is conquered.
One hears about stunting, and the accidents which result from taking chances in the air. There may be two opinions about whether for the flying of the future it should be necessary to loop, to roll, to half roll, and stall turn, or even to spin. As to looping and rolling, the question of the type of machine to be flown will determine that largely. There are many machines which cannot be looped. The large naval flying-boats, for instance, describe a circle two thousand feet in diameter for each turnover--it is almost obvious that not much stunting is done on these boats. A small scout or sporting plane can loop and come out higher than it went in.
There is certain value in practising such maneuvers if the machine will permit it. In battle they are, of course, essential. In peace, however, they may be valuable for the very fact that it accustoms a pilot to unexpected changes in the air. He gets used to the idea that he can pull himself out of any position, given air enough, and he will never be afraid. He becomes orientated on his back, does not lose his head, and simply waits with confidence for his machine to come around. This means that if he is suddenly overturned by accident, or for a minute or two loses control, he knows that his condition is temporary and that he must simply "carry on."
Army pilots who have had a good course in stunting would certainly recommend the same for civilian pilots. That does not mean that it would be necessary, or even advisable. There have been accidents due to stunting by both inexperienced and experienced pilots. Generally it is a matter of altitude, for with sufficient height the greenest pilot can come out of anything, if he does not lose his head.
For the man who would be the pilot for a large commercial plane, such as the Glenn Martin bomber, the Super Handley-Page in England, or the Naval Curtiss flying-boats, no stunting is necessary. He may sit in the cockpit of his machine, and ramble off mile after mile with little motion, and with as little effort as the driver of a railroad locomotive. He has a large, steady machine, and there will be no obligation for him to spill his freight along the course by turning over in midair.
Whatever opinions may be held regarding the advisability of teaching stunting to a civilian pilot, there can be no question that a civilian pilot must have a long and thorough course in the very gentle but essential art of making forced landings. The problem is that of controlling a machine with its engine cut off, to have complete control of it within the radius of its gliding distance. Again, the dart gliding to its uncertain landing. In the hands of an unskilled pilot, an airplane gliding without power is a very dangerous thing. He may pile up the machine against some farm-house, fence, haymow, or clump of woods, smashing it badly and injuring himself. Or he may, through inexperience, lose flying speed in the course of his descent and topple over into a spin.
Even the best pilot may make a mess of his machine if his engine goes "dud" over a forest, city, swamp, or other impossible landing-place. It is his business more or less to keep clear of such tracts when flying. But one of the tests of a good pilot is whether or not he can shut off his engine in the air, pick out his particular field below, taking into account that he must land against the wind, then by a series of gliding turns find himself just coming out of the last turn in front of the fence. He may make a gentle little "zoom" over the fence, using every last bit of flying speed for the last kick, and settle down gently on the other side. One test of instructors in Canada, before they were allowed to take up pupils, was to make three perfect forced landings in succession--one of them as the pilot came out of the spin. With his head still reeling he must pick out his landing-place and make it.
The difficulty is, of course, not to undershoot, to fall short. It must be remembered that in case of actual engine failure there is no motive power, and if a man calculates his distance too short, he has nothing left but to make his landing where he may be. He has lost his height and his chance to reach other fields. He may find himself rolling into the fence of the field he was trying for.
Or, equally bad, he may overshoot. The distance was shorter than it looked, he has more height to lose than he thought. He can gain nothing by sticking the nose down, because in his plunge he gains speed which will carry him too far on the ground. He may bowl over the fence, or, if there is a field beyond, make the next field. More often he finds himself in a patch of woods with a broken airplane.
It is possible that on a turn, a gliding turn with the engine shut off, the pilot may lose his flying speed. Unless he is experienced, he does not realize that on a turn the machine presents more surfaces to the air and greatly increases the air resistance. It is likely to stall unless a safe margin of speed is maintained. The dangerous part of this is that very often the machine will lose its speed when only a hundred feet from the ground, approaching the field. There is no chance to pull it out of a spin unless the pilot is alert and realizes that he has lost speed, and noses down before he spins. Often he spins, and a fall with an airplane from a hundred feet is just as nasty as it can be.
For his own safety in the air the civilian who is about to take up instruction in flying should insist at his flying-school that he be taught thoroughly, to his own satisfaction, the control of his machine with the engine shut off for the moment. There is a certain feel, a sing in the wires, he must know. He should continue at the work of forced landings, going on his solo flights to various heights, pick out his field, shut off the motor, and get down into that field--no other. He should keep it up until he can make nine out of every ten absolutely perfect, and the tenth one, though not perfect, still a good landing.
Then it may be said that a pilot is safe. When he knows in his own heart that nothing can happen to him which will throw him off his guard, or which will worry him, he can take the air without fear.
V
QUALIFICATIONS OF AN AIRPLANE MECHANIC
What chance has a good automobile man who knows his engine thoroughly to become an airplane mechanic? There can be only one answer to this question which men ask themselves daily--there is every chance in the world. Commercial flying, in the day when the air is to become a medium of transportation, just as ground and water are at present, must draw to itself hundreds of thousands of mechanics. The only thing to which the future of flying may be compared is the automobile industry at present. And the only place from which the mechanics are to be recruited are from the men who are working in garages putting automobiles in order.
An interesting comparison between the future for the automobile mechanic or airplane mechanic compared with the future for the pilot is afforded in the figures of a well-known flying-officer of great vision. He expects that the skilled mechanic, the man who has spent years at his trade, will command more for his services than a pilot. Any one can learn to fly an airplane in one or two months of proper training. A mechanic may work for years to learn his profession.
It was estimated that it took ten mechanics of various kinds on the ground to keep one airplane pilot flying in the air, and the experience of the United States has shown that there must be a large force of trained men to keep up flying. The present leaders of the automobile world and the aeronautical world are men who got their first interest in mechanics in some little shop. Glenn H. Curtiss and Harry G. Hawker, the Australian pilot, both owned little bicycle-repair shops before they saw their opportunity in flying.
Most essential of all, for the man who would become an airplane mechanic, is a thorough knowledge of gasolene-engines. This should include not only a knowledge of such fundamentals as the theory of the internal-combustion engine, carburetion, compression, ignition, and explosion, but also a keen insight into the whims of the human, and terribly inhuman, thing--the gasolene-motor. Nothing can be sweeter when it is sweet, and nothing more devilish when it is cranky, than an airplane engine.
There are certain technical details which distinguish an airplane motor from an automobile motor, but a man who knows automobile engines can master the airplane motor in short order. Generally speaking, the airplane motor differs from the automobile motor in shape. The Liberty type of engine is V-shaped, with both sets of cylinders driving toward a common center, the crankshaft. Most airplane motors have special carbureters, and their oiling systems are extremely finely adjusted to take up any friction at their high speed. They will be found to be lighter in weight, with pistons, piston heads and other parts made of aluminium. They are, as a rule, more carefully made than most automobile motors, with especial attention to the fitting of all working parts.
One advantage which an airplane mechanic has is standardization, which has reached a high point with Liberty, Hispano-Suiza, and Curtiss engines. Once a mechanic has learned his type he has learned practically every engine of that type. For a long time to come the 18,000 Liberty engines which this country had at the time the armistice was signed will be carrying commercial airplanes across broad stretches of the United States. If it had not been for the pressure of the war this engine might have been developed slowly, as the automobile engines were, with changes from year to year. The Liberty engine has reached a high standard of efficiency, and is likely to be the standard airplane engine in this country for several years to come. An airplane mechanic who knows his Liberty engine will be able to look after most of the airplanes with which he will come into contact.
An engine which was not developed to the same high point in this country as the Liberty motor is the rotary engine, of which the Gnome Monosoupape or Clerget are perhaps the best-known types. These were favorites with airmen flying fighting scout-planes. They weighed practically nothing, for an engine. A one-hundred-horse-power motor weighed only two hundred and sixty pounds, and it was a splendid type for fast work. Briefly, the power generated by the explosions in the cylinders, operating against two centers of pressure, gave a rotary motion to the cylinders and crankcase, revolving around a stationary, hollow crankshaft. Cylinders and crankcase were bolted together, and the cylinders looked like the blades of an electric fan. There was always an odd number of cylinders, so that there would be no dead-centers, no point at which two opposing strains would be balanced, causing the engine to stop. The propeller was bolted on a nose cap which revolved with the engine. This type of engine is not likely to be used to any extent for commercial flying, or even flying for sport. It is expensive, very wasteful of gasolene and oil, and difficult to keep in repair.
For men who may have had some experience in the assembly of airplanes at factories, or of rigging them at flying-fields, there is great opportunity. Expert riggers who know their craft are few and hard to get. They are invaluable for maintaining a machine in flying condition. The use of airplanes in this country will require men for rigging, for truing up the wires and struts. Each airplane must be overhauled after a few hours of flight to discover hidden weaknesses and to tighten sagging wires.
Rigging an airplane has some resemblance to rigging a ship for sailing. The first requisite is to see that the machine is properly balanced in flying position. There is a number of minute measurements which come with the blue-print of every machine and which must be followed out to the letter to get the most successful results. An important detail is the pitch of the planes, or the angle of incidence, as it is called. This is the angle which a plane makes with the air in the direction of its motion. Too great a pitch will slow up the machine by offering too great a resistance to the air; too small an angle will not generate enough lift. The tail plane must be attached with special care for its position. Its angle of incidence must exactly balance the plane, and it must be bolted on so that there is no chance of it cracking off under strain.
Radio operators will be in great demand for flying. Brig.-Gen. A.C. Critchley, the youngest general officer in the British service, who was a pilot in the Royal Air Force, said that the future development of the airplane must go hand in hand with the development of wireless communication. He added that the most difficult thing about flying, especially ocean flying, was to keep the course in heavy weather. There are no factors which will help a man on "dead" reckoning; and a shift in wind, unknown to the navigator of a plane, will carry him hundreds of miles from his objective. The wireless telephone was used to some extent during the war for communication between the ground and the air; it will be used to a greater extent in the next few years.
Another development which is being used by the navigators flying the Atlantic is the radio compass. This instrument may be turned toward a land or sea wireless station, of which the call is known, and it will register the bearing from the flying-boat to this station. It may be turned upon another station, and this bearing also charted. The intersection of these two wireless compass bearings gives the position of the ship at sea. The radio compass is dependable day or night, and is said to be quite as reliable as a sextant or other navigating instruments.