CHAPTER II
THE BIRTH OF THE AIRSHIP
Progress in the construction of aircraft has been rapid of recent years, but there was a long period of experiment and preparation. It is a long flight from the aircraft of to-day back to the efforts of the Robert brothers in 1784.
The Robert brothers’ experiments took the form of a balloon shaped like a melon, made of silk carefully proved, and measuring 52 feet in length and 32 feet in diameter. The gas employed was pure hydrogen. Underneath the envelope was suspended a long, narrow car, in general idea not unlike that used on some modern airships, and three pairs of oars with blades made like a racquet-frame, covered with silk, and a rudder of similar material.
The two brothers, accompanied by a third person, went up in this early dirigible and succeeded in describing a curve of one kilometre radius, thus showing that, at any rate, they could deviate in some measure from the wind then prevailing. But at the time of the ascent there seems to have been very little opposition in the way of wind pressure. Favourable weather was naturally chosen. Nevertheless, something was attempted and something done, paving the way for further efforts.
Another airship, which led to a thrilling adventure, was built in due course. This was fitted with an internal air ballonet. An ascent was bravely attempted, but the ship got into a strong air eddy, which tore away the oars and rudder and detached the air-bag from its sustaining cords. This airship, however, is said to have reached a remarkable height for those days—no less than 16,000 feet! This, however, was _not_ intentional.
Another airship worthy of note was the dirigible built in France by Henri Giffard. This took a spindle shape, measuring 143 feet in length and 39 feet in diameter. It had a 3 h.-p. steam engine and an 11 foot screw propeller. The first trip was made in September, 1852. Six miles were covered in conditions not entirely favourable, and it is recorded that several further journeys were made. Ten years, however, passed before marked progress was shown in the construction of this type of dirigible.
Tissandier was the next in the field. His dirigible was not unlike previous efforts in shape and construction; but now an electric motor and a bichromate battery were employed, and a speed of eight miles an hour was reached.
Next came Captain Charles Renard, who made marked progress by building an envelope with a ‘true streamline.’ The car was suspended by means of a huge sheet placed over the back of the airship, to which were attached suspensory cords. The cubic capacity of the airship was 66,000 feet. It was kept rigid by means of an internal air ballonet, which was kept full by a fan blower coupled to a motor. It had a car 108 feet in length, which helped to steady the airship, and indeed played a somewhat similar part to the spar employed in later airships of the semi-rigid type. An electric motor, weighing 220 lbs., was installed, which developed 9 h.-p. The first trial trips were made in 1884, and were considered at the time remarkably successful so far as navigation was concerned. Indeed, it is recorded that on one occasion this dirigible flew round Paris at an average speed of 14½ miles an hour—a remarkable achievement at the time.
Clearly there was now a future for airships. Germany had recognized this for some while, and had not been idle. Baumgarten and Wolfert built an airship in 1879 with a benzine motor, but when making an ascent at Leipzig the vessel got out of control, fell to the ground, and was hopelessly wrecked.
In 1897 Wolfert made further experiments, which cost him his life. A fire broke out in the benzine container of the new ship, with the result that the inventor and his assistant were killed.
The same year saw an effort on the part of an Austrian named Schwartz, who built an airship of sheet aluminium. This, however, proved a leaky structure. It descended and came to a sudden end. Schwartz, however, was the first to build a rigid airship with a petrol motor, and there is a sense in which his efforts led to the modern Zeppelin.
With that airship—the modern Zeppelin—with its intricate construction and remarkable capacities of speed and distance, its carrying powers, its evil missions, its tactics when under fire—we shall deal later.