In the 1890s, the
Verein zur Förderung der Luftschifffahrt (an association promoting airflight founded in 1881) conducted scientific balloon ascents to study the upper atmosphere on the initiative of
Richard Assmann. Hans Groß was
Premiereleutnant of the
Berliner Luftschifferabteilung (Berlin airship department), and as balloon pilot took part in 28 of these studies. Hydrogen balloon plans by Groß led to the construction of the
Humboldt. This performed six ascents, two ending in non-fatal crashes; during deflation after its final landing on 26 April 1893, it exploded due to electrostatic charging and burnt. For his next balloon, the
Phönix, Groß developed a variant of the
Reißbahn invented by
John Wise in 1844. This allowed the pilot to rapidly deflate a gas balloon upon landing. The
Phönix performed 23 manned ascents from 1893 to 1896, a total 180 hours in the air and reached a maximum altitude of 9155 metres on 1894-12-04 with
Arthur Berson. == Airships ==