By design
The design of airships are divided into three basic types: soft, semi-rigid and rigid.
In a soft and semi-rigid fabric body systems is also a wrapper for the gas. Semi-rigid airships type distinguished by the presence in the bottom (usually) part of the metal shell (in most cases) farm that prevents deformation of the shell. An example of semi-rigid airship is an airship "Italia". Keel farm consisted of steel triangular frames, connected by the same steel longitudinal stringers. In front of the keel farm was attached bow amplification, is a steel tubular trusses held together by transverse rings, rear - forage development. Also pitching in the farm were suspended gondola: one located control cabin and passenger space, in the three nacelles - engines. In blimps and semirigid systems immutability external shape is achieved pressurized carrier gas, maintains ballonet - bladders located inside the shell, which is injected into the air.
In rigid airships immutability external form for a metal (rarely - wooden) frame covered with cloth, and the gas was inside a rigid frame in bags (balloons) from a gas-tight material. Rigid airships have a number of disadvantages, deriving from the peculiarities of their structure: for example, descend on unprepared ground without the help of people on the ground was extremely difficult, and parking airship on this site, as a rule, ended in disaster, as the fragile skeleton with more or less strong wind inevitably destroyed, frame repair and replacement of its individual parts required considerable time and experienced staff, so the cost of rigid airships was very high.
Frameless monocoque airships - airships design with a metal shell - emerged in 1890 to reduce air resistance. In 1920 began the application of plating of aluminum alloys. In the history of airship was built only four of the airship, and of these only one - an American pilot ZMC-2 - successful (though infrequently) flew in a few years.