Marvels of Modern Science | Page 3

ascended from the Champ de Mars, Paris, in 1853, with fifteen passengers, all of whom came back safely.
The longest flight made in a balloon was that by Count de La Vaulx, 1193 miles in 1905.
A mammoth balloon was built in London by A. E. Gaudron. In 1908 with three other aeronauts Gaudron crossed from the Crystal Palace to the Belgian Coast at Ostend and then drifted over Northern Germany and was finally driven down by a snow storm at Mateki Derevni in Russia, having traveled 1,117 miles in 31-1/2 hours. The first attempt at constructing a dirigible balloon or airship was made by M. Giffard, a Frenchman, in 1852. The bag was spindle-shaped and 144 feet from point to point. Though it could be steered without drifting the motor was too weak to propel it. Giffard had many imitations in the spindle-shaped envelope construction, but it was a long time before any good results were obtained.
It was not until 1884 that M. Gaston Tissandier constructed a dirigible in any way worthy of the name. It was operated by a motor driven by a bichromate of soda battery. The motor weighed 121 lbs. The cells held liquid enough to work for 2-1/2 hours, generating 1-1/3 horse power. The screw had two arms and was over nine feet in circumference. Tissandier made some successful flights.
The first dirigible balloon to return whence it started was that known as La France. This airship was also constructed in 1884. The designer was Commander Renard of the French Marine Corps assisted by Captain Krebs of the same service. The length of the envelope was 179 feet, its diameter 27-1/2 feet. The screw was in front instead of behind as in all others previously constructed. The motor which weighed 220-1/2 lbs. was driven by electricity and developed 8-1/2 horse power. The propeller was 24 feet in diameter and only made 46 revolutions to the minute. This was the first time electricity was used as a motor force, and mighty possibilities were conceived.
In 1901 a young Brazilian, Santos-Dumont, made a spectacular flight. M. Deutch, a Parisian millionaire, offered a prize of $20,000 for the first dirigible that would fly from the Parc d'Aerostat, encircle the Eiffel Tower and return to the starting point within thirty minutes, the distance of such flight being about nine miles. Dumont won the prize though he was some forty seconds over time. The length of his dirigible on this occasion was 108 feet, the diameter 19-1/2 feet. It had a 4-cylinder petroleum motor weighing 216 lbs., which generated 20 horse power. The screw was 13 feet in diameter and made three hundred revolutions to the minute.
From this time onward great progress was made in the constructing of airships. Government officials and many others turned their attention to the work. Factories were put in operation in several countries of Europe and by the year 1905 the dirigible had been fairly well established. Zeppelin, Parseval, Lebaudy, Baidwin and Gross were crowding one another for honors. All had given good results, Zeppelin especially had performed some remarkable feats with his machines.
In the construction of the dirigible balloon great care must be taken to build a strong, as well as light framework and to suspend the car from it so that the weight will be equally distributed, and above all, so to contrive the gas contained that under no circumstances can it become tilted. There is great danger in the event of tilting that some of the stays suspending the car may snap and the construction fall to pieces in the air.
In deciding upon the shape of a dirigible balloon the chief consideration is to secure an end surface which presents the least possible resistance to the air and also to secure stability and equilibrium. Of course the motor, fuel and propellers are other considerations of vital importance.
The first experimenter on the size of wing surface necessary to sustain a man in the air, calculated from the proportion of weight and wing surface in birds, was Karl Meerwein of Baden. He calculated that a man weighing 200 lbs. would require 128 square feet. In 1781 he made a spindle-shaped apparatus presenting such a surface to the resistance of the air. It was collapsible on the middle and here the operator was fastened and lay horizontally with his face towards the earth working the collapsible wings by means of a transverse rod. It was not a success.
During the first half of the 19th Century there were many experiments with wing surfaces, none of which gave any promise. In fact it was not until 1865 that any advance was made, when Francis Wenham showed that the lifting power of a plane of great superficial area could be obtained by dividing the large plane into several parts arranged on tiers.