7 Ferdinand von Zeppelin 7and, in Germany after 1888, gasoline engines were used.
The problem remained how to maintain the shape of
the gas bags. Fully filled with gas under the right pressure,
a cigar shape could be maintained and steered; but a
partially deflated bag was almost impossible to direct. It
was Zeppelin who first saw clearly that maintaining a
steerable shape was essential, so he created a rigid but very
light trussed and covered frame supported by internal gas
cells. This solved many of the steering problems, but how
to give the frame sufficient strength to deal with torque
introduced by air currents in storms continued to be a
severe challenge.
The initial flight (July 2, 1900) of the LZ-1 (for Luftschiff
Zeppelin) from a floating hangar on Lake Constance, near
Friedrichshafen, Ger., was not entirely successful. The
LZ-l flew for 17 minutes before sinking to the surface of
the lake and impaling itself on a buoy that punctured the gas
bag. Nevertheless, it had the effect of promoting the air-
ship to the degree that public subscriptions and donations
thereafter funded the count’s work. After years of cautious
changes in design Zeppelin was ready in 1908 with the
LZ-4, 446 feet (134 metres) long and carrying more than
half a million cubic feet (14,000 cubic metres) of hydrogen.
On July 1 he achieved 12 hours of sustained flight at a speed
of 40 miles (65 km) per hour over central Switzerland.
With the LZ-5, the dirigible became a potentially
practical air transport. A passenger service known as Delag
(Deutsche-Luftschiffahrts AG) was established in 1910,
becoming the first well-financed air transportation com-
pany. In the five-year period up to the outbreak of World
War I Delag made 1,588 flights, safely carrying 34,228
passengers, covering a total of some 170,000 miles
(270,000 km). During the war 88 zeppelins (as they came
to be known) were constructed for military purposes,
among which was the introduction of the first sustained