Leonardo da Vinci

The History of Helicopters

1. Historical Background
2. Stepping Stones to the Helicopter
3. The Helicopter is Born
4. The Helicopter Comes of Age



It has often been said regarding new inventions and advances in technical fields that there is very little that is actually new. What is meant by that, of course, is that somewhere, sometime, along civilization's march of progress, an idea considered a modern day original had already been
thought of. This may be true about some things but not all. For example, atomic energy is certainly a completely new scientific development. The marvelous so-called wonder drugs for curing many of mankind's ills are another. On the other hand the helicopter, that unique and most youthful of all aerial transports, can trace its origins to the hazy years of antiquity. This is so at least to the extent of the craft's basic means of flight, if not to its detailed engineering and mechanical structure.

Many who delight in gleaning facts from the dusty files of aviation's history have come to the conclusion that the Chinese were the first to fly a helicopter. Creators of many of civilization's milestones of progress, the Chinese are said to have built the granddaddy of all rotary-winged aircraft centuries ago. Of course, this was not a real helicopter in the sense that it could carry passengers or even that it looked like any of these craft as we know them today. Rather it was a toy, which has since become known as the Chinese top.

Whose happy mind first conceived this flying toy which has entranced children for many generations the world over is unknown. Exactly how this child's plaything looked when first put together by its inventor is also a bit of a mystery, since many variations of it have been described and flown after it left the Orient for the Western World. Perhaps closest to the original was the one built and demonstrated by Launoy and Bienvenu before the French Academy of Sciences in 1784.

Launoy & Bienvenu helicopter project
Launoy & Bienvenu helicopter project

Their top was made of two rotors, string and wood. Each of the rotors had four feathers and each rotor was about a foot in diameter. The rotors were fastened to opposite ends of a revolving shaft which was slipped through a hole in another piece of wood formed like a bow. The whole unit was a sort of T-shaped affair. The rotors were spun by cord that had first been fastened to the tips of the bow and then twisted around the shaft. As the cord became entwined around the shaft it pulled the ends of the bow upward and itself became very taut. When the top was launched, the pressure of the bow straightening out pulled on the string. This action spun the shaft and rotors very rapidly, causing the device to fly into the air.

Some models of these tops were made in which the whirling force was supplied by human hands. In that case the rod was twirled swiftly between the palms of the hands until the fan became airborne. Later, rubber bands, whale bone, and small but powerful springs were also used for motive power.

Another version of the Chinese top had a two-bladed rotor fastened to the end of a wooden rod. A triangular shaped wing was also fixed to the top side of this wood. The rotor fan was spun about by hand until the rubber-band motor was twisted tight. When the toy was released, it shot into the air with great speed. This toy was sold by Chinese merchants in America about the turn of the century and proved very popular among children.

The author recalls many moments of pleasure he obtained from a metal Chinese top during his boyhood. This toy consisted of three separate parts—a small propeller, a short length of twisted metal, and a piece of tubing about an inch long. The tube and propeller, in that order, were slipped over the twisted rod. One hand held the bottom end of the rod and the other the length of tube. Then the propeller was pushed off the rod with great force. It twirled around at high speed and, once free of its attachment, it rose to a great height in the sky. When the rod was slightly tilted forward, the propeller could be made to fly a good distance from the launching spot.

Sometimes these tops were sold with a string instead of a short length of tube, for spinning the propeller off the shaft. The string had to be wound around a short hub on the prop, and when this was given a quick, hard yank, the propeller whirled off and into the air. What a delight it was to see the spinning wings go flying through the air—and the sad feeling when they failed to return to earth! Sometimes they caught in the upper branches of a tree or rested forever on a rooftop.

Plaything though it was, the Chinese top illustrated perfectly the fundamental principle of the helicopter. Centuries after its appearance in that earliest of civilized nations, it was destined to fire the imagination of scientists and inventors throughout the Western World. Many felt it held the answer to man's age-old dream of rising from his earth-bound realm to that of his feathered friends in the sky above.

Among the ancients this desire to fly was first given expression in the telling of extraordinary legends. These described the strange and wonderful adventures of human flyers who in some mysterious fashion were given birdlike wings to soar and swoop through the sky. Many told of unhappy endings like that of Daedalus and Icarus, perhaps the most famous of all such fantasies.

Icarus had fitted to his back a pair of wings made of waxed bird feathers. Just before he left the earth, his father warned him about flying too high lest the heat of the sun melt the wax and Icarus tumble to earth. But the young man, completely absorbed with the delight of his aerial movements, forgot his father's words of caution. His sky journey ended exactly as his parent had predicted. Icarus flew too close to the sun, which melted the wax. The wings came apart and Icarus fell to his death on the earth below.

From legends, mankind progressed ever so slowly to more serious observations about flying. Perhaps among the earliest that history records are those of Roger Bacon. This thirteenth-century English philosopher was a man of great learning and intellectual ability. He was a prolific writer on scientific subjects, and many of his ideas were greatly in advance of his time. For example, he predicted on numerous occasions that some day man would build a successful flying machine. Bacon even offered a suggestion as to how this machine might look: "... a device for flying shall be made such that a man sitting in the middle of it and turning a crank shall cause artificial wings to beat the air after the manner of a bird's flight."

Although we may look with amusement on this early scientist's description of a proposed aircraft, his writings had an important effect as they slowly made their way through the countries of Europe. They stimulated the minds of other scientists and philosophers on the subject of flying machines and the fascinating prospects they offered. One of the world's most famous of this select group of gentlemen was Leonardo da Vinci.

This great Italian who lived in the golden Renaissance of the fifteen and sixteenth centuries was a versatile genius. Although his greatest and most enduring fame lies in the realm of art, he was equally at home in the world of science, engineering, architecture, and natural philosophy. He left lasting contributions in all these fields of intellectual activity. As he had so many widespread interests, it is little wonder that his mind should be attracted to the magic of mechanical flight. Indeed, aside from his art, the lure of flying occupied more of his mental energies than any of his other interests.

For his study of aeronautics, Leonardo turned to a readily available source provided by nature—bird-life. He spent countless hours roaming the fields, observing the flight of these feathery creatures. His notebooks are filled with dozens of sketches of wing structures, done with great skill and detail. The story is told that on his numerous strolls through the market place of Florence, he would buy several cages of birds from their happy vendors. Walking to an uncrowded area, Leonardo would open the cage doors and watch with great attention as the birds took wing and freedom. Those close to him who witnessed this unusual procedure gaped with puzzled expressions. Some even tapped their heads with a finger, saying in effect, "The poor old gentleman must be slightly out of his mind."

But Leonardo was undisturbed by the glances and remarks of the onlookers. In the fleeting instant when his newly bought birds flew off, he caught perhaps an unusual motion of a wing or a new position of the feathers, and these were soon added to his growing collection of data and sketches. A tiny measure of progress was made in his mind towards the creation of a successful flying machine.

When at last Leonardo had exhausted his study of bird flight and had drunk deeply of the writings of Bacon, he was firmly convinced that human flight was possible. He began designs for his first flying machine, which he modeled after the structure and flight of birds. It was essentially a mechanical arrangement for flapping wings up and down, power to be supplied by the pilot, who was then supposed to be taken aloft by the craft. This type of aircraft has since been classified as an ornithopter, because of its resemblance to bird flight. Many of aviation's first experimenters could think of no better way to propel their flying machines than after the manner of birds. They were convinced if birds could do it, so could men. It was simply a case of duplicating mechanically the same wing motion for human flight—or so they thought. No aircraft of this type has ever been known to fly.

Before becoming amused at these pioneer aircraft builders and their fanciful designs, it is good to remember that the ornithopter airplane has never completely left the minds of inventors. Long after the Wright brothers pointed out the most practical means of heavier-than-air flight, tinkerers with a serious gleam in their eyes pursued the old idea, and in fact are still thinking of a successful ornithopter. Perhaps some day an ingenious individual will hit upon the right combination of power plant and wing structure to bring this about.

As for Leonardo and his ornithopter, he designed and built in model form many variations of this flying machine. With some of these the pilot was to lie prone on a board to which movable wings were attached. By pulling on strings with an arm motion and treading with his legs, the flyer was supposed to make the wings beat up and down and carry him to lofty heights. On other models Leonardo added hand cranks and a rudder shaped like a bird's tail. The rudder was to be fastened to the pilot's neck. When he turned his head to the right, he was supposed to fly to the right, and vice-versa when he moved it to the left.

It is quite certain that Leonardo never advanced out of the model-making stage with his ornithopters. As he became more deeply involved with this particular type of flying machine, he met with innumerable knotty mechanical problems which gradually discouraged him. It was about this time that the idea for a helicopter flying machine entered Leonardo's mind.

Just how Leonardo came to think of the helicopter flying principle is not quite clear. In view of his enormous mental powers, it is conceivable that this could have welled up from his own creative pools of genius. Of course the possibility of his having come in contact with the Chinese top either through his widespread reading or contact with travelers must also be considered. However this may have been, the fact remains that this great Italian designed and built models of the first helicopters intended for human flight.

One of the first of Leonardo's helicopter designs called for a shallow saucer-like gondola on which two upright posts were attached. Each of the posts carried a double set of wings. By means of a rather complicated system of cords, cylinders, and foot pedals, the pilot set the wings in motion with movements of his feet, hands, and head! Alas, the poor flyer, if he suddenly developed a cramp in his leg!

Leonardo da Vinci
Leonardo da Vinci's helicopter project

The wings of this craft were not of the flapping variety, but rather they moved in a horizontal plane, criss-crossing one another. This motion compressed the air between the wings and gave the craft lift. Leonardo provided his helicopter with a landing gear in the form of a pair of ladders about twenty-four feet long. These were intended not only to help the take-offs but also to cushion the craft when it landed. During flight they were supposed to be hauled into the gondola or fuselage.

Unlike many inventors, Leonardo was not above feeling that perhaps, should his helicopter ever reach the flying stage, an accident might occur. Therefore, along with a description of his craft, he also included the very wise suggestion that during the helicopter's test flight, the pilot fly it over water. In the event of an accident, he would thus be tumbled onto this yielding surface and unharmed.

While speaking of Leonardo's caution about flying, it is interesting to note that in connection with his helicopter studies he also devised what was perhaps the world's first parachute. The Italian genius was quite optimistic about his life-saving device; he showed this when he said, "If a man have a tent roof of caulked linen 24 feet broad and 24 feet high, he will be able to let himself fall from any great height without danger to himself."

The helicopter experiments also led Leonardo to design what many believe to be the first airplane instrument. This was a pendulum device that hung within a glass ring. "This ball within the ring will enable you to guide the apparatus straight ahead or aslant as you wish."

Craving perfection in all that he did, Leonardo soon began to feel unhappy with his first helicopter models. One of the major causes of his dissatisfaction was the manner of powering his flying machine. He came to the conclusion—one that was to profoundly affect aircraft experiments in the years ahead—that mechanical rather than human power must be used before a successful flying machine could be built.

With this thought in mind, he undertook some new experiments before designing a different model helicopter. Standing in the center of his studio one day, he took a large, thin ruler and swung it in rapid circles above his head. He felt a distinctive upward pull on his arm. From this he reasoned that if he could build a flying machine having a rapidly rotating wing above it— powered by mechanical means—he would achieve a successful aircraft. Leonardo proceeded to build a model of his new helicopter design, powering it with a spring motor.

Many of the helicopter models which he built are said to have taken to the air successfully. It is quite likely they were fashioned along the lines of those using a coiled spring for a motor. These craft had a wing-like rotor for rising into the air.

Among the last of the helicopter models designed by Leonardo was one which had the appearance of an artificial Christmas tree. More important to the great Italian, it is the design which historians say made him the partial originator of the word "helicopter." He described the craft with a good deal of confidence in its flying ability. "I say that this instrument made with a helix and is well made, that is to say, of flaxed linen of which one has closed the pores with starch and is turned with a great speed, the said helix is able to make a screw in the air and to climb high."

The helix he mentions is a Greek word meaning "spiral" or "twist." This was combined later with another Greek word, pteron, meaning "wing." In still later years through much usage, the words were fused in such a manner that the term "helicopter" came to be born.

As in his many other fields of endeavor, Leonardo da Vinci left his imprint on the very infant subject of aeronautics. By his work with ornithopters and helicopter models he is said to have begun the first sound experiments in search of a practical heavier-than-air flying machine. Leonardo was strongly convinced that if man were to accomplish his long desired goal of traveling in the sky above him, it would be by a flying machine based on the principle of the helicopter. A little more than two hundred years were to pass before Leonardo's ideas on flying machines were to be picked up and carried forward by a whole host of helicopter experimenters. Alas for this band of aeronautical pioneers, man's first ascent into the sky was made by an entirely different type of aircraft, the hot-air balloon.

This historic event took place in 1783 just outside of Paris when two courageous young Frenchmen, Jean-Francois Pilatre de Rozier and Marquis d'Arlandes, rose into a November sky in their hot-air balloon craft. It wasn't many years since the Montgolfier brothers had startled the French people and those of the neighboring countries with the world's first hot-air balloon flights. When word of these pioneering sky journeys spread far and wide, they inspired experimenters and inventors struggling to build flying machines as nothing had stirred them since the days of Leonardo da Vinci.

About this time another event took place that was far less dramatic but was eventually to prove almost as powerful a stimulant to technically minded people absorbed with the youthful science of aviation as the hot-air balloons. This was a demonstration of the flying Chinese top before members of the French Academy of Sciences, probably Europe's first glimpse of this Oriental aerial toy. Normally, these gentlemen were not easily stirred by exhibitions of unusual mechanical devices. But after the flying top had flown gracefully above their heads from one end of the room to the other and then, its energy spent, settled gently to the floor, the hall broke out with a buzz of excitement. What a superb performance! Launoy, a naturalist, and his partner, Bienvenu, a mechanic, who put the top through its paces, were surrounded by the learned gentlemen, all seemingly talking at once with great animation. They were stormed with questions, and the little toy was minutely examined by dozens of hands.

Leaving the Academy at the close of that day's session, many of the scientists were still under the spell of the fascinating aerial plaything. This was especially true of those who were deeply interested in aeronautics. Talking with great animation and gesturing rapidly with their hands, they were convinced they had just been shown the key that would unlock the door leading towards a successful flying machine.

Although the Montgolfier brothers had already shown how man might travel through the air with one type of aerial vehicle, there were many experimenters who felt that a better way would be by some sort of craft having wings, one or more propellers, a body or fuselage, and a mechanical source of power. This, of course, was the heavier-than-air aircraft they were thinking about.

It is interesting to note that in the early nineteenth century the helicopter, as a means of achieving heavier-than-air aircraft flight, was thought of as much as airplanes having fixed wings. And even though the latter won the race of getting into the sky first, the supporters of the helicopter never gave up in their struggle to build a workable machine. Their great loyalty to this type of aircraft and the many superior qualities which they felt it had over other forms, would some day be vindicated.

It did not take long for word of the Chinese top and the principle of rotary flight which it demonstrated to reach scientists in other lands. They, too, were equally enthusiastic about its offering a rather simple solution to what had long been a most baffling problem. Now that the way had been shown, the next step was to try to build an aircraft using its principles that would really fly. Soon the lamps in workshops throughout Europe were burning to the wee hours of the morning as inventors struggled hopefully over their aerial creations. Each felt that his machine would be the first to rise successfully from Mother Earth.

The English Channel was no barrier to the spreading of the news concerning the flying Oriental toy. As elsewhere, it created quite a stir when shown to the scientists and inventors of Great Britain interested in aviation matters. It made a particularly deep impression on Sir George Cayley, who has been fondly called the "father of English aeronautics."

Ever since he was a boy of nine, Cayley had been fascinated with the possibilities of flying. His imagination soared during the late 1700's because of the wonderful hot-air balloon flights of the Montgolfier brothers. Some day, he dreamed, he too would build a flying machine that would astound the world and make his name famous in many lands.

Although he never quite reached his goal, Cayley in time came to be one of England's leading men of science and especially well informed about aeronautics as it existed during his lifetime. For almost half a century he busied himself with aerial experiments, mostly with the balloon type aircraft. He is said to be the first to have begun experiments with gliders which were an important initial step leading towards the successful fixed-wing aircraft.

Cayley was about twenty-three years old when he first came in contact with the top. He was fascinated by the flying toy and in 1796 began building models of his own design, using different means of powering them. Most were driven by springs and rubber bands—the latter a power source familiar to all aircraft model builders of today. Some of Cayley's models were said to have risen almost ninety feet into the air, which was no mean achievement at the time. However, his interest in these models soon waned, and the Englishman gave most of his attention to balloon aircraft.

It wasn't until he was well along in years that Cayley again switched his emphasis in aeronautical studies from the balloon to the heavier-than-air flying machines. It is significant that when he did this, the helicopter was among the more important of the types which he investigated. As evidence that the rotary wing airplane had now deeply impressed the English scientist, he revealed to the public in 1843 his design for a flying machine based on the helicopter principle. He called his sky vehicle an "aerial carriage."

In a sense, Cayley was correct in labeling his aircraft a "carriage." It bore a strong resemblance to a baby's vehicle elaborately decorated for a May Day children's parade. Had it ever ? been built, his design called for two sets of huge rotors, positioned one above the other and connected to the body of the craft by a system of booms. A belt drive, connecting the craft's steam engine and the rotors, spun the latter and supposedly gave the machine its lifting power. When the craft was airborne, two propellers fixed to the stern were intended to power it in a forward direction. The body of the helicopter had a shape somewhat like that of a bird and was canvas-covered. Indeed, a bird's head was used as the design for the front of the helicopter's body.

Cayley helicopter project
Cayley helicopter project

However, the craft had a very unbird-like interior, since its inventor called for a steam engine to be placed within it. The engine powered not only the rotors but the two directional propellers as well. Cayley equipped his helicopter with a four-wheel landing gear together with a broad horizontal rudder to control its upward and downward flight actions. He also included a small vertical rudder for guiding the machine to the right or left.

Cayley's helicopter never actually reached the construction stage. It is quite likely that in the process of working out various engineering features of his craft, especially the power plant, he realized that a much more efficient engine would have to be created—one that produced a great deal more power in relation to its weight than the steam engines of that period—before a flying machine could successfully leave the ground. This stumbling block to a practical flying machine of these early years—either helicopter or fixed-wing aircraft—was to dawn slowly on each individual experimenter as one by one they met with discouraging failure.

Cayley died at the age of eighty-four. It is said that his interest in aeronautical matters was just as keen during the fading days of his life as it was in his youth. For the fine pioneering work he accomplished in a field of science still in its infancy during his day, he was honored with knighthood.

About the time that Sir George was experiencing a new interest in helicopters, a countryman of his, W. H. Phillips, was busying himself with similar studies. Like the knighted Sir George, Phillips was a scientist who had a strong curiosity in aeronautics—a curiosity that was intensified by Cayley's achievements. Just a year before the latter revealed his plans for a helicopter "aerial carriage," Phillips went a step further and produced an actual flying model of a steam-powered rotary wing aircraft. Driven by a midget-sized steam-engine, the entire device weighed about twenty pounds. Phillips' miniature helicopter was remarkably successful. It made a number of fine nights. One of the last of these the inventor described in his notes with some pride: "The steam was up in a few seconds, when the whole apparatus spun around like a top and mounted into the air faster than any bird; to what height it ascended I had no means of ascertaining. The distance traveled was across two fields where, after a long search, I found the machine minus the wings, which had been torn off from contact with the ground." The English inventor's helicopter was a substantial contribution to the science of aeronautics of that day. It was the first steam-powered model helicopter to fly successfully. The aerial contrivance was also outstanding because its system of propulsion was based on the jet principle. Steam was made to squirt out of tiny openings in the arms of the rotor, spinning them around and carrying the machine into the sky.

When news of the model rotary wing airplane circulated among scientific groups, it was considered nothing short of sensational. Some engineers became overly enthusiastic about Phillips' flying machine, and soon there was talk of building large passenger-carrying helicopters. These bold ideas quickly faded when it was realized that a much more suitable power unit other than the bulky steam engine would be needed before their dreams could become a reality.

Cayley and Phillips were probably unaware of it, but at about the same time of their helicopter experimental activities, another gentleman with scientific interests was also thinking of this aerial machine for transportation purposes. Vittorio Sarti was his name. He lived in the same country where a little more than two hundred years earlier, Leonardo da Vinci was busily laying the groundwork for the science of aeronautics. Indeed, it is quite likely that Sarti was a student of the work of his famous countryman, since his version of an aircraft embodied many of the basic ideas of Leonardo.

Sarti's flying machine was a combination of the ornithopter and the helicopter. He was obviously determined to make his , craft fly by one means or another. It had huge square blades— three of these being grouped in each rotor. The latter were positioned on a vertical shaft one above the other, an arrangement described by present-day helicopter engineers as a coaxial system. The blades were hinged to the shaft in order that they could flap up and down, similar in action to a bird's wing. This motion was supposed to lift the inventor's craft straight up off the ground.

The remainder of the Italian engineer's helicopter had a large triangular-shaped rudder for steering in forward flight. This was fastened to a boom which extended from the rear of the pilot's compartment, a circular structure that hung below the flapping rotor blades. There is no record that Sarti's helicopter flying machine ever left the ground.

While the work of the three helicopter experimenters just described might have little value as far as contributing anything important towards the building of a successful rotary wing aircraft is concerned, it had historical significance. Their efforts .were among the first of more than a hundred years of painfully slow and often bitterly disappointing work before the first really successful helicopter was created. Throughout the nineteenth and twentieth centuries, helicopter study, experiment and development work proceeded, first at a snail's pace and then at an ever accelerated rate. At first this activity was concentrated in a few countries in Europe, with France the main workshop. French scientists and technical men had a particular fondness for flying craft of all sorts and for a long time their country was considered the world's center of aviation developments. It wasn't unusual, therefore, when Gabriel de la Landelle along with two associates, Gustave Ponton d'Amecourt and Felix Tournachon more popularly known as Nadar) designed a helicopter flying machine that astounded the public of their day.

This craft was intended to be a real leviathan of the skies Which the aeronauts aptly called the "steam air-liner." The designers were lavish with the creation of their brain-child by including not only all the features they considered necessary to make it fly, but also many others for the comfort and safety of the passengers.

To start with, it had a boat-shaped hull or fuselage from either side of which the builders fixed large rectangular wings. These were kept in a rigid position by wires which were fastened to two tall masts. These last were imbedded vertically in the fuselage. On the upper portions of the masts were the rotors—four of them—one above the other. The optimistic designers felt that these would be sufficient to lift the giant hulk off the ground.

Passengers inside the cabin who felt the air getting too stuffy for their comfort could climb a stairway to a rail-enclosed upper deck. At the fore and aft ends of the hull, the designers placed triangular-shaped fins which were probably intended to guide the craft in horizontal as well as up and down flight. A propeller was also placed at the front of the airliner which was supposed to pull it in a forward direction.

Taking no chances in the event their omnibus of the sky should develop mechanical difficulty, the investors included parachutes and a life boat as safety devices. The parachutes were attached to the tops of each of the masts, and while the craft was sailing serenely on its aerial journey, they were collapsed like the arms of an umbrella. In fact when the parachutes were opened, they resembled giant umbrellas. It was hoped, of course, that the 'chutes would ease the massive helicopter back to earth gently in case of emergency.

The life-boat hung below the fuselage. It was probably thought valuable in case the helicopter ran into trouble while flying over water. The inventors certainly could not be accused of lacking foresight.

Landelle and his associates intended their sky giant to be powered with the only available means of that day for driving mechanical contrivances, the steam engine. This spun not only the rotors but the forward propeller as well.

As events turned out, the steam air liner never reached the construction stage. It became a symbol of lofty plans that failed of accomplishment both because of material and human shortcomings.

While the three French helicopter designers were busy working out the details for their air giant, one of the group, Gustave Ponton d'Amecourt, had an additional helicopter project under way which he was handling all by himself. In comparison with the air liner, this craft, a model, incidentally, was about the size of a beetle. The Frenchman's flying machine had two sets of small rotors of two blades each. They were placed one above the other on top of the machine and were spun about by a small steam engine. Gustave Ponton d'Amecourt was a clever mechanic, and his tiny helicopter was an extremely neat and efficient looking affair. Perhaps more important than its aircraft features was the tiny steam engine. This unit was considered quite advanced for its day since its creator had made considerable use throughout its construction of a new metal, aluminum.

In 1868 scientists and engineers of Great Britain who were deeply engrossed with aeronautical matters put their heads together one day to discuss the status of that youthful science. The majority agreed that, on the whole, many wonderful accomplishments had been made up to that time. Someone then made the suggestion that it would be nice if an exhibition were held where many of aviation's achievements—mostly in the form of flying machines—could be seen by the public. Exhibits would be shown from other countries along with those of Great Britain.

The idea was received with great enthusiasm, and shortly thereafter, in June of 1868, the world's first aeronautical exhibition was held in the Crystal Palace in London. Crowds poured into the great hall to see the varied shaped balloons and aircraft which their inventors had hoped would open up a brand new field of transportation. The d'Amecourt helicopter model was one of the craft on display and it drew more than its share of curious onlookers.

Paucton was still another French engineer who, at the time of the London air exhibit, sought to solve the problem of heavier-than-air flight with a helicopter. However, he would have no part of the word "helicopter" to describe his aircraft, although its basic principles were of that type. Instead, he called his aerial vehicle a "pterophore." Further, Paucton decided not to follow in the steps of his contemporaries and use mechanical power to drive his craft. The method of the ancient experimenters with their human energy for propulsion was good enough for him.

The helicopter was to have two propellers, or "pterophores" as the inventor identified them, one to provide the craft with lift and the other forward motion. These were hooked up with cords and pulleys to a crank arrangement. The pilot, seated in Ira chair, was supposed to turn the crank as fast as he was physically able, and this in turn spun the rotor overhead to lift him off the ground. Also this motion turned the propeller at the rear for movement forward.

Paucton called for a unique feature in his lifting rotor or "pterophore." The blades of this unit were to be made adjust-» able so that from a spoke-shaped position they could be moved to form a continuously closed surface. Thus, in the event the pilot met with trouble while aloft, the inventor felt confident that this solid disc parachute would "resist the flow of air and retard the fall of the machine to a considerable degree."

There is no record that Paucton ever built or attempted a flight with his hand-powered helicopter or even that he put his unique parachuting device to a test. If he did, he probably made the rueful discovery that man is poorly equipped physically to imitate the birds for propelling himself through the air. Paucton's machine contributed little if anything to the art of building a successful helicopter. The same could not be said for a rotary wing aircraft model built several years later by Enrico Forlanini of Italy.

Forlanini was a professor of civil engineering who, like many others in his profession, was fascinated with the flying possibilities of the helicopter. Studiously quiet, he loved to tinker in his little workshop after classroom lectures. It was here, after good deal of thought and effort, that the helicopter model took form. In due time the flying machine created much excited comment with its graceful aerial antics.

The Italian engineer's craft weighed almost eight pounds, which, in view of the fact that he powered it with a steam engine, was a splendid technical accomplishment. Indeed, this unit, cleverly designed by Forlanini, was as outstanding a part of the model aircraft as its flight performances. The propulsive force of the engine was created by super-heated water contained in a hollow globe hanging beneath the apparatus. This globe was two-thirds filled with water and then heated. When the desired pressure was obtained, a valve was opened which permitted the steam to flow to the engine's cylinders. Their movement spun the large rotor overhead.

To the delight and astonished gasps from many of those who saw it, the professor's little helicopter would rise from the ground and fly along for a distance of many feet. On some of these flights it rose to a height of forty feet and stayed aloft for as long as twenty seconds. Following the footsteps of the Englishman Phillips, Forlanini had succeeded in building the world's second successful steam-powered helicopter model.

It is not to be supposed that helicopter development activity of the nineteenth century was confined to the gentlemen discussed thus far. It wasn't. There were a host of others in other countries of Europe each contributing a tiny measure of additional knowledge that some day would bring into being a successful helicopter. What is more, this engineering work was not restricted to the old world. The United States, youthful, vigorous and growing, also had its scientific, mechanically-minded men who were intrigued with the idea of building a flying machine. Destiny, indeed, selected this country as the scene where man would some day achieve his long sought goal of building the first successful flying machine.

Long before the Wright brothers were sailing in their experimental gliders over the sand dunes of Kitty Hawk, a lonely figure of a scientist was bent over his drafting board in a New York City home putting finishing touches to his design for an aerial machine. At last Mortimer Nelson straightened up. This was it, and at once he dispatched his brain child to the United States Patent Office. Nelson was granted a patent on his flying device on May 21, 1861, and as far as is known, this is the earliest record of an American attempt to build a helicopter.

The New York scientist's aerial invention at first was merely considered an improvement for balloon aircraft. His helicopter device, which he called an "aerial car" was to be used along with a balloon. He explained, "The nature of my . . . invention consists in revolving fans, applied to balloons and arranged in such a manner that they can be used for communicating a vertical ascending movement, or a forward propulsion." Later he developed more confidence in his flying machine, so that he felt it could be operated by itself.

Nelson's combination helicopter-balloon aircraft consisted of a body which tapered fore and aft, a pear-shaped rudder at the stern, a parachute canopy over the top of the fuselage and two vertical shafts rising out of the body, each equipped with a pair of rotors. A canvas material or oiled silk was suggested for covering the car, rudder, and parachute. He arranged the rudder in such fashion that it could control the craft's upward, downward, and sidewise flying directions.

Nelson helicopter project
Nelson helicopter project

Nelson's helicopter had several very advanced engineering features for its day. One of these concerned the rotors. Nelson didn't care particularly how many were placed on his aerial car just so long as there was a minimum of two and that others were added in pairs. The rotors and their shafts could be fixed in an upright position or inclined forward. In describing them, he said, "when the shafts stand vertically . . . the revolution of them will tend to raise the balloon or car and that when . . . inclined forward their action on the air will give propulsion to the car." This was anticipating by almost a hundred years another type of aircraft, the convertiplane.

Nelson also realized that the rotors had to spin in opposite directions; otherwise a peculiar force of physics which engineers call "torque" would turn his car in one direction while the fans revolved in another. It is for that reason that Nelson insisted on rotors being installed in pairs.

The other feature which distinguished Nelson's helicopter design was his recommendation for the use of aluminum for all the craft's metal parts. Aluminum was scarcely as well known then as it is now; iron and steel were more commonly used for mechanical apparatus. Nelson was aware, however, that its light weight in comparison to iron and steel would be a great advantage in helping his craft to fly better. In this connection, he wrote, "I have discovered that by making the framework . . . of aluminum, a sufficient strength can be obtained, and the great weight usually in such parts so much removed that the sustaining power has not as much weight to lift as would be the case in any engine . . . made of iron, steel or other metals." Nelson had again anticipated modern day airplane builders by many decades.

The parachute or awning device which Nelson called for in his design was not meant for safety. This was to be installed over the top of the car at an angle and serve the same purpose as a wing to give the craft lift. According to Nelson's own explanation of this feature, "The parachute . . . gives outstanding power to the car in moving through the air and forms a buoyant sail."

Nelson failed to provide one very essential item for his helicopter as described in his patent. He didn't say how the aerial vehicle was to be powered. Perhaps this was because the inventor was aware that some means of propulsion other than the heavy steam engine would be necessary before his craft could fly. Evidence of this is shown by the fact that Nelson conducted experiments on a revolutionary lightweight internal combustion engine. As a result of his efforts along this line, he obtained still another patent on a chemical mixture to be used in his new engine. He called it "carbo-sulphethal."

Nelson made some very optimistic claims for his new fuel mixture and engine. Not only would his new engine be far lighter than the conventional steam power unit, but it would also burn a good deal less fuel while producing the same amount of energy. Mortimer Nelson, alas, never transformed his paper-designed helicopter into real life substance.

In West Dennis, Massachusetts, meanwhile, another inventor was pressing the New Yorker for the honor of obtaining this country's first patented helicopter design. He was Luther C. Crowell, and his aerial device was recognized by the Patent Office on June 3, 1862.

Crowell's machine called for some unique mechanical features. For example, the two propellers with which it was equipped were fastened to shafts that could be swung from a vertical position to a horizontal. Thus, when it was flying as a helicopter, that is, in a vertical direction, the propellers would be above the aircraft's body. For forward flight they were supposed to be lowered to a horizontal position. Incidentally, he also realized that these had to rotate in opposite directions to counteract torque. In addition to the movable propellers, the designer also equipped the craft with adjustable wings. For up and down flight the wings could be lowered to a vertical position. After reaching the desired altitude, the pilot was then supposed to bring the wings up horizontally for flying in a forward direction. Another curious thing about the wings was the fact that they were hollow and were to be filled with hydrogen or some other lifting gas. Wood and a covering of either oiled cloth or silk was suggested for their construction. Once aloft, the helicopter was supposed to be steered in any desired direction by a pyramid-shape rudder fixed to the stern of the fuselage. This was accomplished by means of cords and pulleys extending into the pilot's compartment.

Crowell helicopter project
Crowell helicopter project

Like most of his contemporary aircraft inventors, Crowell was precise with his directions for building the structure of his flying machine. About ways of powering his helicopter, however, he was quite vague. He merely called for a steam engine. The inventor probably felt that the problems of installing a power plant as bulky as this was so great, they had better be left to someone else.

Crowell worked out his helicopter design just as the American Civil War was getting under way, which undoubtedly influenced his thoughts concerning possible uses for his flying machine. He suggested that it could be used for bombing purposes. "When it is desired to employ this aerial machine as an engine of war, it could be elevated, loaded with shell, and when arrived over the desired spot the shell could be discharged," he commented.

The New England inventor, however, was not the only one thinking of the flying machine, more particularly the helicopter, as a means for waging war. In the South with similar ideas was Captain William C. Powers.

Captain Powers was inspired to invent his flying machine by the Union blockade of Confederate ports. He thought of it as a wonderful means to get around the Union Navy which was preventing the import of badly needed war supplies. In addition, he also saw his invention as an excellent device for observation and reconnaissance work. It was a crude-looking machine and had hardly any resemblance to an aircraft. The helicopter had two rotor units in the form of spiralling screws which were supposed to lift the craft vertically, and a series of similar units on the sides for propelling it through the skies. Presumably a steam engine was to be the power source.

Powers helicopter project
Powers helicopter project

The Confederate officer's helicopter design is a comparatively recent discovery. It is said that he never tried to build a full-scale model of his flying machine because he was afraid it might fall into Union hands and be used against the Southerners. He need not have troubled himself with this thought. According to aviation authorities, his helicopter never would have left the ground under any circumstances.

The mid-1800's was a banner time for American inventors to try their hand at designing flying machines. To those of Nelson, Crowell, and others, John Wooton added his in 1866.

A native of Boonton, New Jersey, he invented a machine featuring a large ring-shaped wing beneath which hung two circular compartments. One of these held the power plant and the other, directly beneath it, was for passengers. The cautious inventor designed his wing in this fashion with the thought in mind that its parachute-like qualities would help bring the machine back to earth in one piece if anything went wrong while aloft.

Wootton helicopter project
Wootton helicopter project

The helicopter was supposedly powered with a steam engine which turned two or more propellers that were fixed between the wing and the topmost gondola. Again we see an American inventor anticipating the convertiplane by designing the propellers to tilt either vertically or horizontally. Indeed, Wooton had many features in his design aside from the one above that were not to be seen again until the modern days of aviation.

For example, his flying machine had a hoisting device within it by which the passenger's compartment could be raised or lowered while the machine hovered over one spot. Present-day helicopters are equipped with similar mechanical hoists capable of doing the same thing. He also called for catapulting apparatus to launch his aircraft into the skies. This was a sort of roller-coaster affair on which the helicopter was supposed to be hauled to a high point at one end. With everything set for the take-off, the machine was released and left to roll down one incline and up the next, at which time, by the combination of lift given by the parachute-wing and whirling propellers, the machine was to become airborne.

Landing and stopping the helicopter after a flight called for still greater skill on the part of the flyer. Although designed to descend vertically, the vehicle was expected to roll after its wheels touched the ground. To stop the craft, the pilot had to aim it between two upright poles. A hook fastened to the topmost portion of the flying machine grabbed ropes which stretched between the uprights and halted the craft. Although the method is different, basically, the present-day navies of the world use somewhat the same means of bringing aircraft to a stop on the decks of carriers.

Even though the New Jersey inventor never reached the stage of building his helicopter, his work can be considered important in the rotary-wing field if only for the many novel and advanced engineering features which he called for in his design.

Ward helicopter project
Ward helicopter project

Other American inventors during this era who sought to solve the problem of mechanical flight by means of the helicopter, included John Ward of California, who obtained a patent on his contrivance in 1876. With its multiplicity of tubes, gears, and whirling propellers, Ward's aircraft resembled most closely a flying pipe organ.

Greenough helicopter project
Greenough helicopter project

Three years later John Greenough came out with a patented design that was a slight improvement. Calling his machine an aerobat, this Syracuse inventor fashioned his helicopter in the form of a giant bird's wing. The craft's two lifting rotors whirled around in two large circular openings cut into the wings. A boat-shaped fuselage was suspended beneath the wing.

Quinby helicopter project
Quinby helicopter project

A month before Greenough received his helicopter patent, another was issued to Watson Quinby on August 12, 1879. A native of Wilmington, Delaware, Quinby had long been interested in aviation experiments and built many unsuccessful machines patterned after the mechanics of bird flight. For his last attempts at building a practical flying machine he turned to the helicopter, which he was confident offered the easiest solution to a long sought goal. Quinby's helicopter, with its four rigid legs for a landing gear, inclined body, and a long nose boom to which were fastened two small sails for a propeller, looked more like an aerial steed than a flying vehicle. The lifting propeller or rotor was also made of a pair of small sails, which were supposed to whirl around a vertical shaft, above the body of the machine.

Johnston helicopter project
Johnston helicopter project

In 1888 another Southerner, Edward Johnston of Alabama, entered the aviation field with his ideas for a workable helicopter. His design was patented in June of that year and resembled for all the world the paper aircraft models which school boys make to plague their teachers.

Johnston's flying machine had six propellers, four for vertical flying and two for giving it directional flight. An interesting detail about these propellers was the fact they had their own individual motors. In addition to being capable of flying in up and down and forward directions, the inventor claimed, his machine could also hover, like a humming-bird, over one area.

Of all the helicopter experimenters during these last years of the nineteenth century, Thomas Edison was unquestionably the best known. He was interested for a long time in the great variety of mechanical problems which a successful flying machine offered. He was convinced from the start, that the helicopter would be the best means of achieving man's dream of conquering the sky.

In 1880 Edison began his experiments with rotary-wing aircraft. To aid him in his work financially, James Gordon Bennett, a famous newspaper publisher of that day and an enthusiastic supporter of aviation activities, provided him with one thousand dollars. First the famous inventor investigated the characteristics of various designs of rotor blades, to discover those having the best lifting power. To do this he erected a rather cumbersome apparatus having a vertical shaft to which the test rotors were attached. He powered these vertically mounted propellers with an electric motor, since the internal combustion engine was not yet in existence.

The electric motor in turn was placed on a wooden base, and the entire unit connected to weight-measuring scales. Thus, as the rotors spun overhead, Edison could tell by reading the scales how many pounds the propellers were able to lift. After prolonged tests with various styles of rotor blades, the inventor discovered that with the only means of powering them at his command, they could only raise a small part of the total weight of his testing apparatus which added up to 160 pounds. He came to the conclusion, therefore, that helicopter flight could be solved only after a suitable engine was created. He was thinking of one that had little weight, yet could produce a good deal of horsepower. Edison had run afoul of the same obstacle that had tripped many other aircraft experimenters before him.

The renowned American inventor was not one to give up easily, however, when faced with a brow-knitting technical problem. He set to work building his own engine and soon was ready to try it. Along with his other notes on helicopter experiments, he wrote, "I used stock-ticker paper made into guncotton and fed the paper into the cylinder of the engine and exploded it with a spark. I got good results, but burned one of my men pretty badly and burned off some of my own hair and didn't get much further."

Following this near-fatal incident, Edison was forced to abandon his helicopter experiments for other more pressing work. However, he never lost his strong feeling that some day the world would see a workable helicopter, as he showed when he said, "I knew that it was only a matter of experimenting and I reported to Mr. Bennett that when an engine could be made that would weigh only three or four pounds to the horsepower, the helicopter would be a success."

More than fifty years later Edison's prediction was to come true but not quite the way he imagined. Helicopter experimenters who followed in his footsteps had to solve problems just as difficult as his before the first successful helicopter could take to the sky.

From "Flying Windmills" by Frank Ross, 1953

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