CHAPTER V PRACTICAL DEVELOPMENT OF NON-RIGID DIRIGIBLES In 1899 the Lebaudy brothers, wealthy sugar refiners in Paris, commissioned their able engineer, Julliot, to make investigations and develop plans for a large and swift air ship. This he did with the assistance of Surcouf, a well-known manufacturer of balloons at Billancourt, Paris. Emulating the example of Santos-Dumont and certain German aëronauts in making their plan, they adopted the light petroleum engine for motive power, but experimented on a larger scale, thus creating a new era in military aëronautics in France. Their first vessel was the _Jaune_ whose bag was built at Surcouf’s place, and its mechanical part at the Lebaudy Sugar Refinery. When launched, in 1902, it so pleased the owners that they determined to continue the experiments on a larger scale. Their second air ship, called the _Lebaudy_, after fulfilling various tests, was accepted by the French government and formed the beginning of its modern aërial fleet. Moisson, near Paris, where the balloons were kept, now became quite an aëronautical center. Here, under military supervision and the skillful management of the aëronaut Juchmes, other dirigibles were built in rapid succession. Of these the _Patrie_ was launched in 1906, and the _République_ in 1908, both fine swift vessels capable of voyaging many hours and carrying many passengers. The Lebaudy vessels were the first air ships of the “semi-rigid type,” in which the long and flexible envelope, or hull, is provided with a rigid keel or floor, from which the car is suspended with its machinery and passengers. They are, therefore, of unusual interest both for their scientific design and for the stimulus they imparted to the growth of aërial fleets. For this reason they may well be studied in some detail. The first Lebaudy air ship, called the _Yellow_, because of its color, had an envelope constructed of a rubber-treated cotton fabric, made in Hanover and covered with a yellow coating of lead chromate, to ward off the sun’s actinic rays from the rubber, and thus prevent deterioration. Her hull, which was cigar shaped and inflated with hydrogen, measured 183 feet in length, 32 feet in diameter, and 80,000 cubic feet in volume. She was propelled by a 40-horse-power Daimler motor actuating twin screws, and attained a maximum speed of twenty-six miles an hour. During her first year’s service she made many ascensions, returning to her starting point twenty-eight times out of twenty-nine. Her longest voyage, made at Moisson, June 24, 1904, was sixty-two miles in two hours and three quarters, with an average speed of twenty-two miles an hours. But in November, 1902, while landing in a high wind at the end of her voyage from Paris to Chalais-Meudon, she was wrecked by colliding with a tree. Her motor, however, was uninjured, and a new envelope was at once prepared.