GROSS II.
(Courtesy E. L. Jones.)
The second Gross air ship, built in 1908, cubed 176,000 feet, and attained a speed of 27 miles per hour, driven by two 75-horse-power Daimler motors. On September 11th of that year, with four persons aboard, she made a round trip from Berlin lasting 13 hours, covering 176 miles, and attaining altitudes up to 4,000 feet. This was one of the finest voyages known at the time. This air ship was purchased by the German government, named Gross I, and sent to Metz. A detailed description is given in [Appendix III].
The Gross II, brought forth in April, 1909, resembled her predecessor in build, but had greater power and speed. Her hull cubed 176,000 cubic feet, had a blunt bow, full body and sharp stern, was provided with horizontal and vertical keels, a sliding weight, and a ballonet at either end. She was propelled by two Körting engines of 75 horse power each, actuating two three-blade propellers. Under the action of her keels and stabilizing planes and rudder, her motion was steady and precise. A special feature of this air ship was the wireless telegraph equipment by which she could send messages in all directions over a range of 300 miles or more. She made many practice voyages during the season of 1909, sometimes alone, again in concert with other auto balloons and with troops. In August she made a fine voyage of sixteen hours, from Tegel to Apolda and return, traversing 470 kilometers.
The above described vessel was followed by others, large and small. The Gross III measured 70 meters long, cubed 7,500 meters, and was propelled by four Körting motors aggregating 300 horse power. This was a splendid vessel, and one of extraordinary speed.
Various auto balloons of the Parseval type were designed by Major Von Parseval of the Bavarian army, who also was one of the inventors of the kite balloon. Satisfactory experiments with his air ship were made as early as 1906. These formed the basis of larger vessels, subsequently constructed in the same factory of August Riedinger of Augsburg, for the Motor Air Ship Study Society, of which Parseval was general manager. This society, organized practically at the command of the Emperor, purchased the Parseval patents and began the development of auto balloons as a business enterprise, soon furnishing a series of its flexible air ships to the German army.
After the experiments of 1906, the Parseval air ship was enlarged from 2,500 to 2,800 cubic meters, its length becoming 52 meters and its major diameter 8.7 meters. Its hull was of cylindric form, with rounded bow and egg-shaped stern; had two air bags—one fore, the other aft—and at the stern carried two fixed horizontal planes and a vertical rudder. From this envelope the car, made largely of aluminum, was hung by steel cables, and on its bottom had trolley wheels resting on suspension cables joining the front and rear parts of the hull. The vessel was propelled by a 50-horse-power Mercedes motor actuating a four-blade screw propeller 13 feet in diameter, mounted between the car and hull. This screw was made of thin steel tubes covered with shirting. Among the merits of Parseval’s air ship may be mentioned its lightness and demountability, and its kite-like effect on the air, got by canting the hull while the car, rolling on the suspension cables, allowed the screw mounted above it to thrust horizontally. The canting was effected by giving one ballonet more air than the other, thus causing its end of the hull to sink. The speed was about twenty-five miles per hour.
PLATE IX.
