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.