Chapter VIII: Flying Machines: How to Operate

Instinctive balance--When the motor skips--Progressive
experience--Plum Island School methods--Lilienthal’s
conclusions--The Curtiss mechanism and controls--Speed
records--Cross-country flying--Landing--Essential
qualifications--Ground practice--Future relief.

Any one who has learned to ride a bicycle will recall the great difficulty at first experienced to preserve equilibrium. But once the knack was gained, how simple the matter seemed! Balancing became a second nature, which came into play instinctively, without conscious thought or effort. On smooth roads it was not even necessary to grasp the handle-bars. The swaying of the body was sufficient to guide the machine in the desired direction.

Much of this experience is paralleled by that of the would-be aviator. First, he must acquire the art of balancing himself and his machine in the air without conscious effort. Unfortunately, this is even harder than in the case of the bicycle. The cases would be more nearly alike if the road beneath and ahead of the bicyclist were heaving and falling as in an earthquake, with no light to guide him; for the air currents on which the aviator must ride are in constant and irregular motion, and are as wholly invisible to him as would be the road at night to the rider of the wheel.

And there are other things to distract the attention of the pilot of an aeroplane--notably the roar of the propeller, and the rush of wind in his face, comparable only to the ceaseless and breath-taking force of the hurricane.

The well-known aviator, Charles K. Hamilton, says:--“So far as the air currents are concerned, I rely entirely on instinctive action; but my ear is always on the alert. The danger signal of the aviator is when he hears his motor miss an explosion. Then he knows that trouble is in store. Sometimes he can speed up his engine, just as an automobile driver does, and get it to renew its normal action. But if he fails in this, and the motor stops, he must dip his deflecting planes, and try to negotiate a landing in open country. Sometimes there is no preliminary warning from the motor that it is going to cease working. That is the time when the aviator must be prepared to act quickly. Unless the deflecting planes are manipulated instantly, aviator and aeroplane will rapidly land a tangled mass on the ground.”

At the same time, Mr. Hamilton says: “Driving an aeroplane at a speed of 120 miles an hour is not nearly so difficult a task as driving an automobile 60 miles an hour. In running an automobile at high speed the driver must be on the job every second. Nothing but untiring vigilance can protect him from danger. There are turns in the road, bad stretches of pavement, and other like difficulties, and he can never tell at what moment he is to encounter some vehicle, perhaps travelling in the opposite direction. But with an aeroplane it is a different proposition. Once a man becomes accustomed to aeroplaning, it is a matter of unconscious attention.... He has no obstacles to encounter except cross-currents of air. Air and wind are much quicker than a man can think and put his thought into action. Unless experience has taught the aviator to maintain his equilibrium instinctively, he is sure to come to grief.”

The Wright brothers spent years in learning the art of balancing in the air before they appeared in public as aviators. And their method of teaching pupils is evidence that they believe the only road to successful aviation is through progressive experience, leading up from the use of gliders for short flights to the actual machines with motors only after one has become an instinctive equilibrist.

At the Plum Island school of the Herring-Burgess Company the learner is compelled to begin at the beginning and work the thing out for himself. He is placed in a glider which rests on the ground. The glider is locked down by a catch which may be released by pulling a string. To the front end of the glider is attached a long elastic which may be stretched more or less, according to the pull desired. The beginner starts with the elastic stretched but a little. When all is ready he pulls the catch free, and is thrown forward for a few feet. As practice gains for him better control, he makes a longer flight; and when he can show a perfect mastery of his craft for a flight of 300 feet, and not till then, he is permitted to begin practice with a motor-driven machine.

The lamented Otto Lilienthal, whose experience in more than 2,000 flights gives his instructions unquestionable weight, urges that the “gradual development of flight should begin with the simplest apparatus and movements, and without the complication of dynamic means. With simple wing surfaces ... man can carry out limited flights ... by gliding through the air from elevated points in paths more or less descending. The peculiarities of wind effects can best be learned by such exercises.... The maintenance of equilibrium in forward flight is a matter of practice, and can be learned only by repeated personal experiment.... Actual practice in individual flight presents the best prospects for developing our capacity until it leads to perfected free flight.”

The essential importance of thorough preparation in the school of experience could scarcely be made plainer or stronger. If it seems that undue emphasis has been laid upon this point, the explanation must be found in the deplorable death record among aviators from accidents in the air. With few exceptions, the cause of accident has been reported as, “The aviator seemed to lose control of his machine.” If this is the case with professional flyers, the need for thorough preliminary training cannot be too strongly insisted upon.

Having attained the art of balancing, the aviator has to learn the mechanism by which he may control his machine. While all of the principal machines are but different embodiments of the same principles, there is a diversity of design in the arrangement of the means of control. We shall describe that of the Curtiss biplane, as largely typical of them all.

In general, the biplane consists of two large sustaining planes, one above the other. Between the planes is the motor which operates a propeller located in the rear of the planes. Projecting behind the planes, and held by a framework of bamboo rods, is a small horizontal plane, called the tail. The rudder which guides the aeroplane to the right or the left is partially bisected by the tail. This rudder is worked by wires which run to a steering wheel located in front of the pilot’s seat. This wheel is similar in size and appearance to the steering wheel of an automobile, and is used in the same way for guiding the aeroplane to the right or left. (See illustration of the Curtiss machine in Chapter V.)

In front of the planes, supported on a shorter projecting framework, is the altitude rudder, a pair of planes hinged horizontally, so that their front edges may tip up or down. When they tilt up, the air through which the machine is passing catches on the under sides and lifts them up, thus elevating the front of the whole aeroplane and causing it to glide upward. The opposite action takes place when these altitude planes are tilted downward. This altitude rudder is controlled by a long rod which runs to the steering wheel. By pushing on the wheel the rod is shoved forward and turns the altitude planes upward. Pulling the wheel turns the rudder planes downward. This rod has a backward and forward thrust of over two feet, but the usual movement in ordinary wind currents is rarely more than an inch. In climbing to high levels or swooping down rapidly the extreme play of the rod is about four or five inches.

Thus the steering wheel controls both the horizontal and vertical movements of the aeroplane. More than this, it is a feeler to the aviator, warning him of the condition of the air currents, and for this reason must not be grasped too firmly. It is to be held steady, yet loosely enough to transmit any wavering force in the air to the sensitive touch of the pilot, enabling him instinctively to rise or dip as the current compels.

View of the centre of the new Wright machine, showing method of
operating. Archibald Hoxsey in the pilot’s seat. In his right
hand he holds a lever with two handles, one operating the warping
of the wing tips, and the other the rudder. Both handles may be
grasped at once, operating both rudder and wing tips at the same
moment. In his left hand Hoxsey grasps the lever operating the
elevating plane--at the rear in this type. The passenger’s seat
is shown at the pilot’s right.]

The preserving of an even keel is accomplished in the Curtiss machine by small planes hinged between the main planes at the outer ends. They serve to prevent the machine from tipping over sideways. They are operated by arms, projecting from the back of the aviator’s seat, which embrace his shoulders on each side, and are moved by the swaying of his body. In a measure, they are automatic in action, for when the aeroplane sags downward on one side, the pilot naturally leans the other way to preserve his balance, and that motion swings the ailerons (as these small stabilizing planes are called) in such a way that the pressure of the wind restores the aeroplane to an even keel. The wires which connect them with the back of the seat are so arranged that when one aileron is being pulled down at its rear edge the rear of the other one is being raised, thus doubling the effect. As the machine is righted the aviator comes back to an upright position, and the ailerons become level once more.

There are other controls which the pilot must operate consciously. In the Curtiss machine these are levers moved by the feet. With a pressure of the right foot he short-circuits the magneto, thus cutting off the spark in the engine cylinders and stopping the motor. This lever also puts a brake on the forward landing wheels, and checks the speed of the machine as it touches the ground. The right foot also controls the pump which forces the lubricating oil faster or slower to the points where it is needed.

The left foot operates the lever which controls the throttle by which the aviator can regulate the flow of gas to the engine cylinders. The average speed of the 7-foot propeller is 1,100 revolutions per minute. With the throttle it may be cut down to 100 revolutions per minute, which is not fast enough to keep afloat, but will help along when gliding.

Obviously, travelling with the wind enables the aviator to make his best speed records, for the speed of the wind is added to that of his machine through the air. Again, since the wind is always slower near the ground, the aviator making a speed record will climb up to a level where the surface currents no longer affect his machine. But over hilly and wooded country the air is often flowing or rushing in conflicting channels, and the aviator does not know what he may be called upon to face from one moment to the next. If the aeroplane starts to drop, it is only necessary to push the steering wheel forward a little--perhaps half an inch--to bring it up again. Usually, the machine will drop on an even keel. Then, in addition to the motion just described, the aviator will lean toward the higher side, thus moving the ailerons by the seat-back, and at the same time he will turn the steering wheel toward the lower side. This movement of the seat-back is rarely more than 2 inches.

Diagram showing action of wind on flight of aeroplane. The force
and direction of the wind being represented by the line _A B_,
and the propelling force and steered direction being _A C_, the
actual path travelled will be _A D_.]

In flying across country a sharp lookout is kept on the land below. If it be of a character unfit for landing, as woods, or thickly settled towns, the aviator must keep high up in the air, lest his engine stop and he be compelled to glide to the earth. A machine will glide forward 3 feet for each foot that it drops, if skilfully handled. If he is up 200 feet, he will have to find a landing ground within 600 feet. If he is up 500 feet, he may choose his alighting ground anywhere within 1,500 feet. Over a city like New York, a less altitude than 1,500 feet would hardly be safe, if a glide became necessary.

Mr. Clifford B. Harmon, who was an aeronaut of distinction before he became an aviator, under the instruction of Paulhan, has this to say: “It is like riding a bicycle, or running an automobile. You have to try it alone to really learn how. When one first handles a flying machine it is advisable to keep on the ground, just rolling along. This is a harder mental trial than you will imagine. As soon as one is seated in a flying machine he wishes to fly. It is almost impossible to submit to staying near the earth. But until the manipulation of the levers and the steering gear has become second nature, this must be done. It is best to go very slow in the beginning. Skipping along the ground will teach a driver much. When one first gets up in the air it is necessary to keep far from all obstacles, like buildings, trees, or crowds. There is the same tendency to run into them that an amateur bicycle rider has in regard to stones and ruts on the ground. When he keeps his eye on them and tries with all his might to steer clear of them, he runs right into them.”

When asked what he regarded the fundamental requirements in an aviator, Mr. Harmon said: “First, he must be muscularly strong; so that he will not tire. Second, he should have a thorough understanding of the mechanism of the machine he drives. Third, mental poise--the ability to think quick and to act instantly upon your thought. Fourth, a feeling of confidence in the air, so that he will not feel strange or out of place. This familiarity with the air can be best obtained by first being a passenger in a balloon, then by controlling one alone, and lastly going up in a flying machine.”

Mr. Claude Grahame-White, the noted English aviator, has this to say of his first experience with his big “No. XII.” Bleriot monoplane--which differs in many important features from the “No. XI.” machine in which M. Bleriot crossed the English Channel: “After several disappointments, I eventually obtained the delivery of my machine in working order.... As I had gathered a good deal of information from watching the antics and profiting by the errors made by other beginners on Bleriot monoplanes, I had a good idea of what _not_ to do when the engine was started up and we were ready for our first trial.... It was a cold morning, but the engine started up at the first quarter turn. After many warnings from M. Bleriot’s foreman not on any account to accelerate my engine too much, I mounted the machine along with my friend as passenger, and immediately gave the word to let go, and we were soon speeding along the ground at a good sixty kilometers (about 37 miles) per hour.... Being very anxious to see whether the machine would lift off the ground, I gave a slight jerk to the elevating plane, and soon felt the machine rise into the air; but remembering the warnings of the foreman, and being anxious not to risk breaking the machine, I closed the throttle and contented myself with running around on the ground to familiarize myself with the handling of the machine.... The next day we got down to Issy about five o’clock in the morning, some two hours before the Bleriot mechanics turned up. However, we got the machine out, and tied it to some railings, and then I had my first experience of starting an engine, which to a novice at first sight appears a most hazardous undertaking; for unless the machine is either firmly held by several men, or is strongly tied up, it has a tendency to immediately leap forward. We successfully started the engine, and then rigged up a leash, and when we had mounted the machine, we let go; and before eight o’clock we had accomplished several very successful flights, both with and against the wind. These experiences we continued throughout the day, and by nightfall I felt quite capable of an extended flight, if only the ground had been large enough.... The following day M. Bleriot returned, and he sent for me and strongly urged me not to use the aeroplane any more at Issy, as he said the ground was far too small for such a powerful machine.”

Diagram of Bleriot monoplane, showing controlling lever _L_
and bell-shaped drum _C_, to which all controlling wires are
attached. When the bell is rocked back and forward the elevator
tips on the rear plane are moved; rocking from side to side moves
the stabilizing tips of the main plane. Turning the bell around
moves the rudder.]

The Marmonier gyroscopic pendulum, devised to secure automatic
stability of aeroplanes. The wheels are driven by the aeroplane
motor at high speed. The pendulum rod is extended upward above
the axis and carries a vane which is engaged by any gust of wind
from either side of the aeroplane, tending to tilt the pendulum,
and bringing its gyroscopic resistance into play to warp the
wings, or operate ailerons.]

The caution shown by these experienced aviators cannot be too closely followed by a novice. These men do not say that their assiduous practice on the ground was the fruit of timidity. On the contrary, although they are long past the preliminary stages, their advice to beginners is uniformly in the line of caution and thorough practice.

When the aeroplane is steered to the left, the pendulum swings to
the right and depresses the right side of the plane, as in (_c_).
The reaction of the air raises the right side of the plane until
both surfaces are perpendicular to the inclined pendulum, as in
(_d_).

Diagrams showing action of Marmonier gyroscopic pendulum.]

Even after one has become an expert, the battle is not won, by any means. While flying in calm weather is extremely pleasurable, a protracted flight is very fatiguing; and when it is necessary to wrestle with gusts of high wind and fickle air currents, the strain upon the strongest nerve is a serious source of danger in that the aviator is liable to be suddenly overcome by weariness when he most needs to be on the alert.

In that inclined position the aeroplane makes the turn, and
when the course again becomes straight, both the gyroscopic and
centrifugal forces cease, and the pendulum under the influence
of gravity becomes vertical. In this position it is inclined to
the left with respect to the planes, on which its effect is to
depress the left wing and so right the aeroplane, as in (_e_).

Diagram showing action of Marmonier gyroscopic pendulum.]

Engine troubles are much fewer than they used to be, and a more dependable form of motor relieves the mind of the aviator from such mental disturbance. Some device in the line of a wind-shield would be a real boon, for even in the best weather there is the ceaseless rush of air into one’s face at 45 to 50 miles an hour. The endurance of this for hours is of itself a tax upon the most vigorous physique.

With the passing of the present spectacular stage of the art of flying there will doubtless come a more reliable form of machine, with corresponding relief to the operator. Automatic mechanism will supplant the intense and continual mental attention now demanded; and as this demand decreases, the joys of flying will be considerably enhanced.

If, when pursuing a straight course, the aeroplane is tilted by
a sideways wind (_b_), the action of the pendulum as described
above restores it to an even keel, as in (_a_).

Diagrams showing action of Marmonier gyroscopic pendulum.]