CHAPTER IV
We have now traced the art of balloon guidance and propulsion from its earliest inception to the close of the nineteenth century. It was a period of extravagant hope and chimerical scheming, but withal a period fruitful in devices of fundamental value. The best experiments paid no dividends, but they prepared the way for really useful vessels. The methods of manipulation and control had been sufficiently developed to answer immediate needs. The air ship was at least dirigible, if not practical. It kept its shape, obeyed its rudder, rose and fell according to the operator’s will. It was, however, a fair-weather machine, beautiful in appearance, but helpless in any considerable wind. Speed was now the desideratum, and the attainment of this involved new difficulties. The storm-proof balloon was still a dream.
Naturally one inquires what velocity makes a dirigible air ship really practical, assuming all other requirements satisfied. The minimum allowable speed depends largely upon the locality and season. On Long Island an assured velocity of forty to fifty miles an hour would seem desirable; for there the winds are swift and the water near. In Washington, or Berlin, thirty miles an hour is enough, though each additional mile per hour must be regarded as a considerable gain on a small margin of progress in facing a stiff breeze. Colonel Renard has estimated, from a study of the wind records near Paris, that a dirigible is practically useful in that locality if it can maintain a speed of twenty-eight miles an hour for ten or twelve hours; since in that case it can maneuver 81 days in 100.
Renard’s own graceful ship attained a speed of but half that much. In order, therefore, to give his vessel the desired usefulness its speed must be doubled. This would require an eightfold[11] increase of motive power without increase of weight. Evidently then the cardinal requisite was a light durable motor of extraordinary output. Such motors fortunately were now coming into the market, owing to the development of gasoline engines for automobile racing.
The year 1898 witnessed the commencement of two famous systems of navigation by the lighter than air, one in France, the other in Germany, destined quickly to revolutionize the art, and to establish it on a practical basis. The leading exponents of these two systems were Señor Don Alberto Santos-Dumont, a rich young Brazilian living in Paris, and Count Ferdinand von Zeppelin, Germany’s stanch old admiral of the air. Both achieved success by applying the gasoline engine to the propulsion of elongated balloons, but by very different methods. Santos-Dumont, apparently ignoring, or fearing to adopt, the excellent hull and car designed and used by Renard, began where Tissandier left off, with a symmetrical hull and low-hung car, thus producing a safe aërial pendulum, if not a racing machine; then by degrees he gradually felt his way to something more efficient. Zeppelin began with a long cylindrical hull pointed at the ends, rigidly framed like that of Schwartz, and supporting its car and propellers well aloft near the line of resistance. His was a bold and effective design but difficult to execute. Santos-Dumont scored the first success, and startled the world by his spectacular flights; but ere long he was surpassed by other builders of non-rigid balloons. Zeppelin won his success slowly and by heroic perseverance in the face of enormous obstacles, finally emerging as the most successful and illustrious figure in the history of aëronautics. The achievements of these two pioneers and colleagues make the first decade of the twentieth century memorable in the annals of aërial navigation.
Santos-Dumont, who spent his early years on his father’s large coffee plantation in Brazil, had, during boyhood, dreamed of navigating the air, and in 1897, at the age of twenty-four, made in France his first ascension in a spherical balloon. While living at Paris during that year he gave much time to motorcycling, automobiling and operating spherical balloons, of which he possessed two constructed after his own ideas; one, the smallest in the world, designed for solitary voyages, the other large enough for more than one person, intended for social excursions. Thus by way of amusement, and probably by impulse rather than deliberate purpose, he was equipping himself to become both the designer and the pilot of his future dirigibles.
Having acquired experience and skill in operating both balloons and engines, the young enthusiast set about realizing his boyhood dream of navigating the air independently of the course of the wind. His first dirigible was designed to carry his weight of 110 pounds and a 3½ horse-power petroleum engine taken from his tricycle, and reduced in weight to 66 pounds. The hull was a cylinder of varnished Japanese silk, 82½ feet long including its pointed ends, 11½ feet in diameter and 6,354 cubic feet in gas capacity. A ballonet, or air pocket, occupied the lower middle of the envelope. The basket for the little pilot, engine, and two-blade propeller was suspended far below the hull, to which its cords were attached by means of small wooden rods inserted into hems along each side of the envelope, for a great part of its length. The poise of the vessel was controlled by shifting weights fore and aft, while the turning right and left was effected by means of a silk rudder stretched over a steel frame. On the whole it was a crude and primitive affair, but of considerable interest as the first dirigible of a young man destined to give a strong impulse to the development of motor balloons of the non-rigid type.
After some preliminary tests, the little air ship and pilot soared away from the Zoölogical Garden in Paris, on September 20, 1898, rising in the face of a gentle wind, to the wonder and delight of a large crowd of witnesses, some of them professional aëronauts and very skeptical as to the outcome of this venturesome experiment. The ship maneuvered round and round overhead of the applauding throng, steering readily in all directions. Then the green navigator ascended a quarter of a mile and merrily continued his evolutions in the direction of the Longchamps race course. But when he wished to descend he observed the envelope contracting in volume, and was appalled to find that he could not pump air into the ballonet fast enough to keep the hull distended. It became swaybacked, and “all at once began to fold in the middle like a pocket-knife; the tension cords became unequal and the balloon envelope was on the point of being torn by them.” As he was falling swiftly toward the grassy turf at Bagatelle, he called to some boys who were flying kites, to grasp his guide-rope and run against the wind. They understood and ran so swiftly with the canted balloon that it played kite, and descended with a moderated fall, landing the frightened aëronaut safely on the turf.
Except for the doubling of his long balloon, Santos-Dumont’s first voyage was satisfactory, and he returned to Paris elated. He had found it easy to steer in all directions. He could change his level hundreds of feet without discharge of gas or ballast, by merely canting his balloon, and allowing it to run obliquely up or down grade. He had stemmed the wind and gone whither he pleased, at such speed as to make his clothes flutter. And best of all he had found no danger in using a gasoline motor near an inflammable gas bag. The mere buckling of the long bag was a trifle, to be remedied by using an air pump adequate to maintain the flabby thing well inflated. He felt, therefore, that he had the conquest of the air well in hand, and that he was drifting into air ship construction as a life work. Small wonder that he continued his conquests till he had built, in less than one decade, fourteen motor balloons.
Santos-Dumont No. 2 was closely patterned after its predecessor, but was a little larger and carried a rotary fan worked by the motor, to keep the balloon plump by filling the air pocket, or ballonet. On May 11, 1899, an ascension was made from the old starting place, but in rainy weather. As the vessel rose its hull contracted faster than air could be pumped into the ballonet, the long bag doubled worse than before, and dropped into the trees with its chagrined but fearless rider.
The No. 3, which followed, was a short, thick vessel, 66 feet long by 25 feet in diameter, having in outward appearance the features of Dupuy de Lome’s very stable and very slow dirigible. It was apparently a safety ship for a scared young man who had not yet learned fully to appreciate Renard’s elegant design. It served for a few pleasant trips, while the inventor was screwing up courage to build another cylindrical vessel, and gradually realizing the advantage of an elongated car such as Renard had employed in La France. Not only was the hull short and thick, but it was further secured from buckling by a horizontal stiffening pole placed between it and the basket, and from which the latter was hung. After some voyages in No. 3, which the captain found very tractable, and probably capable of fifteen miles per hour, he was ready to begin a new vessel.
The No. 4 was a compromise between the better features of No. 3 and its predecessors. The elongated hull and ballonet were resumed, and the stiffening pole was elaborated into a longish car resembling Renard’s, but of triangular cross section. On this long trussed frame were placed the motor, propeller, rudder and the rider in his basket. A seven horse-power engine turning, at one hundred revolutions per minute, a screw propeller having two blades, each 13 feet across, gave a thrust of 66 pounds. Frequent trials of the ship during the summer of 1900, in presence of the Exposition crowds, brought the inventor into extraordinary prominence, and secured for him the “Encouragement Prize” of the Paris Aëro Club, consisting of the yearly interest on one hundred thousand francs, this being one of M. Deutsch’s numerous foundations for the promotion of aëronautics.
In the spring of 1900, M. Deutsch de la Meurthe had established another prize which Santos-Dumont now greatly coveted, and hoped ere long to win. This was a cash sum of one hundred thousand francs to be awarded by the Scientific Commission of the Aëro Club of France to the first dirigible that, between May 1 and October 1, 1900, 1901, 1902, 1903, 1904, should voyage from Saint Cloud to and around the Eiffel tower, and return within half an hour. The distance to the tower and back, not counting the turn, was nearly seven miles, and the estimated speed required to fulfill the conditions for winning the prize, even in calm weather, was 15½ miles per hour.
As Santos-Dumont thought his No. 4 scarcely swift enough to win the Deutsch prize, he enlarged it by inserting an additional length of sixteen feet at its middle, supplied it with a stronger car, and applied a larger engine, naming the new vessel so formed, his No. 5. Its hull was 109 feet long, 17 feet in largest diameter and cubed nearly 20,000 feet. A four cylinder air-cooled petroleum motor driving a screw propeller having two blades, each 13 feet across, gave a thrust of 120 pounds, at 140 revolutions per minute, and produced such draft as to give the inventor pneumonia. Among other novelties water ballast was used, and piano wires replaced the old-time suspension cords.
The No. 5 proved so powerful and swift that on July 13, 1901, Santos-Dumont attempted to win the Deutsch prize. Starting from the Aëro Club grounds at Saint-Cloud in presence of official witnesses, at half past six in the morning, when the air is usually stillest, he turned the Eiffel Tower in the tenth minute, thus gaining twenty minutes for the home stretch. But on his return he encountered an unexpected head wind, and after a terrific struggle reached the timekeepers at Saint-Cloud in the fortieth minute.
To add to the romance of this voyage, the genii of the upper elements stopped his motor, shortly after his return, and the bold sailor in his shining ship landed in a stately chestnut tree very near the house of the Princess Isabel, daughter of Dom Pedro. She very thoughtfully arranged a breakfast for him and sent it up in a basket, where he was at work disengaging the balloon, at the same time inviting him to call and relate to her the story of his voyage. A few days later she sent him a medal of St. Benedict “that protects against accidents.” He wore the medal, and on his very next trial escaped without a scratch from an appalling accident which might have terminated fatally. He continued to wear the gift of that gracious princess, on a thin gold chain circling his wrist, and many a time thereafter endured unscathed the most dreadful accidents, as if he possessed a charmed life.
On August 8, 1901, the dauntless aëronaut again sailed for the coveted prize, at the same still morning hour, sacred to duels and aërial contests. In nine minutes he turned the tower and headed bravely for home. But soon a leaky valve let the balloon shrink and the wires sag into the whirring propeller, which therefore had to be stopped. Santos-Dumont now had the choice of drifting back against the tower and destroying his vessel high in air, or of descending at once, by allowing the balloon to sink without discharge of ballast. He chose the latter course, hoping to land on the Seine embankment; but instead his balloon struck the top of the Trocadero hotel, exploded and fell in fluttering shreds into the courtyard. Some firemen who had been watching the flight from a distance, came with a rope and found the long car leaning like a ladder against the wall of the court, the balloon shreds hanging from it in graceful folds, and Captain Santos-Dumont perched aloft in his wicker basket wearily waiting for St. Benedict’s further aid. As usual, he was rescued intact.
On the evening of his fall on the roof of the hotel Santos-Dumont issued specifications for his famous No. 6, which surpassed all its predecessors in safety and speed. It had the shape of an elongated ellipsoid with pointed ends, measured 110 feet in length, 20 feet in major diameter, 22,239 cubic feet in volume, and had an absolute ascensional force of 1,518 pounds. It was driven by a twelve horse-power four-cylinder water-cooled engine which gave the propeller a thrust of 145 pounds. To insure against buckling of the gas bag, an air pump connected with the motor, kept the ballonet under constant pressure, regulated by an escape valve through which the excess of air passed outward. To secure the envelope against rupture, due to the expansion of the hydrogen at unusual elevations, a stronger valve was used to let the gas escape from the envelope into the atmosphere. Thus the air escape valve kept the pressure constant in the partially distended ballonet, and consequently also in the surrounding gas envelope itself; while the stronger gas valve in the envelope opened only in an emergency, when the gas pressure had fully collapsed the internal air pocket and was threatening to explode the envelope. With all its improvements this new vessel was finished and inflated by August 4, being a work of twenty-two days, and after some preliminary trials was ready to try for the Deutsch prize.
The day of triumph followed quickly. On October 19, 1901, at 2.45 P. M., Santos-Dumont again headed for the Eiffel Tower in presence of the official witnesses. In spite of a wind of six meters per second striking him sidewise, he held his course straight for the goal, and turned it in the ninth minute, as in his preceding attempt. On the return he had to struggle against a quartering wind and the caprice of his motor, which sometimes threatened to stop, and again spurted so actively as to turn the ship upward at a steep angle. The mighty throng below, in the Auteuil race track and the Bois de Boulogne, sent up immense applause, then suddenly held its breath in alarm, as the vessel pitched violently. But the hardy little rider was self-possessed and at home on his vaulting Pegasus. Alert to every prank he held his course straight for the timekeepers and passed over their heads at exactly twenty-nine and one-half minutes after starting.
His unmercenary disposal of the two rich awards which he had won seemed no less commendable than the dauntless industry which achieved such rapid success. The Deutsch prize amounting in all to one hundred and twenty-five thousand francs he divided into two unequal parts. The greater sum of seventy-five thousand francs he gave to the prefect of police of Paris, to be used for the deserving poor; the remainder he distributed among his employés. The Encouragement Prize of four thousand francs a year, mentioned before, he also declined to retain, but instead he founded with the money a new prize at the disposal of the Aëro Club. As a second reward for his triumphal voyage around the Eiffel Tower, he received from the Brazilian government one hundred and twenty-five thousand francs and a beautiful gold medal bearing appropriate and very complimentary inscriptions.
Now that the stimulus and excitement of striving for the Deutsch prize was over, the ardent inventor was free to develop and test his air ships in a deliberate and scientific manner. He therefore set about building specialized types of motor balloons, and practicing with them over all kinds of territory, smooth and rough. Within the next six years he constructed eight more air ships making altogether fourteen, besides his various free balloons, to say nothing of the aëroplanes and hydroplanes which he found time to develop. But before indulging in these new luxuries he would have more experience with his No. 6.
When the cold weather set in, following his victorious flight about the Eiffel Tower, Santos-Dumont went with his No. 6 to Monaco, to practice air cruising over the Mediterranean. The Prince of Monaco had erected for him an “aërodrome,” or balloon shed, facing the sea and very near shore. On pleasant days the daring pilot would cruise up and down the bay, not far from shore, trailing his guide-rope over the waves with the greatest ease, and to the applause of thousands of spectators. But on February 14, 1902, he set forth on a pleasure cruise over the bay with insufficient gas pressure, and thus came to grief. The bag grew flabby; the hydrogen poured to its higher end; the vessel reared up so steeply that the propeller had to be stopped to avoid its cutting the envelope. Rather than drift at the mercy of the wind, the pilot opened the valve and sank slowly to the water where he was rescued by a boat. On the following day the parts of his No. 6 were fished out of the sea and sent back to Paris. His few days’ practice had taught him the delights of guide-roping over the waters, and his accident induced him in future to sew unvarnished silk partitions across his balloons, to prevent the hydrogen passing too suddenly from one end to the other.
Returning to Paris he built for himself an “aërodrome,” provided with great sliding doors like the one at Monaco, and equipped with a hydrogen plant, constructive appliances, and everything needed for the rapid rebuilding or repair of air ships. It stood in a vacant lot surrounded by a high stone wall and was made of posts covered with red and white canvas, so that it looked like a great striped tent. Inside, the central stalls were 31 feet wide, 165 feet long, and 44½ feet high,[12] the whole enclosure having accommodation for seven dirigibles all inflated and ready for instant service. When completed, in the spring of 1903, it was at once used to harbor three new air ships. These were the No. 7, designed for racing contests; the No. 9, called the Runabout, a minim air ship used for calls and short pleasure trips; and the No. 10, called the Omnibus, intended for several persons, with ample supplies for a considerable journey.
The No. 7, which excelled its predecessors in length and bulk, was intended greatly to outstrip the best of them in velocity. The first air ship had attained fourteen miles per hour, the No. 6, nearly twenty miles an hour in winning the Deutsch prize, and over twenty miles per hour on subsequent occasions, though provided with a motor rated at only 12 horse power. The new vessel which had little greater resistance than No. 6, was to carry four times the internal pressure, or about 12 centimeters of water, and to be propelled by an engine of 60 horse power. The inventor expected therefore to attain a speed of between forty and fifty miles per hour. A very lofty expectation for that day, and one still unrealized for many years.
The racing air ship, or No. 7, was of cigar form, supporting a long car beneath, and generally resembling the No. 6, but slightly more tapering. Her length was six times her major diameter, and her volume 45,000 cubic feet. The envelope was made of two layers of the strongest French silk, four times varnished, and was built exceptionally thick at the stern, where the differential outward pressure is greatest in flight. The propulsion was effected by a 60 horse-power water-cooled four-cylinder Clément engine actuating two screw propellers 16½ feet in diameter, one in front the other at the rear of the car. The poise and maneuvering were to be controlled in the usual way, by means of the rudder and shifting weight. The inventor seemed not to realize that the bow of his vessel was too sharp to cleave the air with minimum resistance, though his predecessor, Jullien, in 1850, had discovered experimentally that a torpedo form is better for speed than the symmetrical spindle form used by Santos-Dumont in his racing vessel. He did, however, in time, learn that the torpedo form of hull is better for stability of forward motion, and hence adopted that form in his little Runabout.
The No. 9 was a thick torpedo-shaped air ship originally cubing only 7,770 feet, though later enlarged to 9,218 feet. It was so thick as to appear nearly egg-shaped. In order to make it respond promptly to the rudder Santos-Dumont drove it through the air blunt end foremost, but with apparent regrets, thinking that it would cleave the air more easily than sharp end foremost. In this he was mistaken; for the writer has shown that a body of such shape encounters much more resistance—roughly one hundred per cent more—when driven sharp end foremost than when driven blunt end forward. This fact furnishes one reason why most whales and swift fishes have blunt bows and long tapering sterns. However this be, the practical man felt his way to success, whether right or wrong in his theory of resistance. When actuated by a three horse-power Clément motor, weighing 26½ pounds, the little air ship carried its jaunty pilot twelve to fifteen miles an hour on many a merry trip about Paris and its environs.
The No. 10, or Omnibus, was a well shaped vessel of nearly eighty thousand cubic feet capacity, and amply provided with steering devices. Its hull tapered slightly from front to rear, terminating in projectile-shaped ends, and had a length of nearly six times its major diameter. Underneath was suspended a long car provided with aëroplane surfaces, in addition to the usual rudder, for controlling its movements.
Its arrow-like appearance was suggestive of some of the greatest German balloons of the decade. Indeed, the Omnibus, if well powered, might have proved a very swift vessel, in addition to a powerful carrier. But she was designed merely for easy going passenger service, for the purpose of popularizing aëronautics and stimulating its growth.
Santos-Dumont now had three typical air ships, a spacious and well equipped “aërodrome,” and ample facilities for advancing the science of motor balloons on a moderate scale. He could not, however, maintain the ascendency in this branch of science in France; for he encountered the rivalry of great wealth employing highly trained engineering and constructive talent. He could, however, still promote the art as a pioneer and a popularizer. This he continued to do. With his little Runabout he would one day guide-rope along the boulevard, another day take up a little boy, another day send up a beautiful young lady to navigate the air alone for a short distance, another day voyage over the military parade grounds and with his revolver fire a salute of twenty-one shots to the President of France, and give exhibitions to arouse the interest of the War Department. But he could not keep pace with the new giants in aëronautics, and he did not attempt it. Nor did he ever build a vessel of sufficient power, speed and durability to be purchased by the French nation. That honor went to his opulent contemporaries who had not failed to take cognizance of his contributions to the aërial art.