page_title: Berlin scientific balloon flights
section_title: Balloons
hierarchical_section_title: Berlin scientific balloon flights / Technical equipment / Balloons
caption_attribution_description: English: Hans Georg Friedrich Groß (1860-1924), German balloonist and airship constructor Deutsch: Hans Georg Friedrich Groß (1860-1924) ,deutscher Ballonfahrer und Luftschiffkonstrukteur
context_page_description: The Berlin scientific balloon flights were a series of 65 manned and 29 unmanned balloon flights carried out between 1888 and 1899 by the German Society for the Promotion of Aeronautics to investigate the atmosphere above the planetary boundary layer. The flights were organized by Richard Aßmann, Professor at the Meteorological Institute of Berlin, who also developed the most important of the measurement instruments employed by them. The execution lay primarily in the hands of the military airship pilot Hans Groß and the meteorologist Arthur Berson. In 1894, Berson flew with the balloon Phönix to a height of 9155 meters, the highest that any human had flown until then.
context_section_description: Sixteen different balloons were used for the 65 manned balloon flights. These ranged from the balloon Falke, which had a gas volume of 290 cubic meters and was used as the "bad weather balloon" when strong winds or bad weather made it impossible to use the larger balloons, to the 3000 cubic meter Majestic of the Briton, Patrick Alexander. About three-quarters of the flights were made on the large balloons M. W., Humboldt, Phönix, Sportpark Friedenau I and Sportpark Friedenau II. The gas used for lifting was hydrogen or the cheaper coal gas, or frequently a mixture of the two.
  The balloon Phönix was of special significance, as it was especially constructed by Groß for scientific flights. It had enough lifting power to make high-altitude flights possible. Its hull was built from two layers of rubberized and vulcanized cotton fabric. It contained two valves of different sizes: the smaller was to allow the release of filling-gas during manoeuvres in flight, while the larger was to empty the balloon after landing. In response to the crash-landing of the Humboldt after its sixth flight, Groß fitted the Phönix with a newly developed "Reißbahn" (rip-track), that was stuck to the rest of the hull before the start of the flight. By pulling on the Reißbahn, the balloon pilot could open up the balloon hull wide, to allow a rapid deflation without causing it to be destroyed in the process. Additionally, the balloon's fabric was regularly impregnated with a 10% solution of calcium chloride, to make it electrically conductive and thus prevent electrical sparking due to electrostatic charging, following a suggestion from Bartsch von Sigsfeld.
  For a safe landing, most balloons carried a heavy anchor. After the development of the Reißbahn, these were superfluous and so often omitted from later flights. In most cases, the equipment included a tow line, that was about 100 m long in smaller balloons, and 150 m for larger ones. Aviators breathed in oxygen through tubes from steel gas cylinders during high-altitude flights to avoid altitude sickness.
  The tethered balloon Meteor was made from varnished silk and could reach an altitude of about 800 meters when filled with 130 cubic meters of coal gas. The measurement balloon Cirrus, made from the same material, was a former military tethered balloon with a fill volume of 250 cubic meters. On its fifth flight it carried measurement instruments to an altitude of almost 22 kilometers. Cirrus II was made of rubberized silk of lower quality and had a volume of 400 cubic meters.
caption: Hans Groß
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