A rigid airship is a type of airship in which the envelope is supported by an internal framework rather than by being kept in shape by the pressure of the lifting gas within the envelope, as in blimps and semi-rigid airships. Rigid airships are often commonly called Zeppelins, though this technically refers only to airships built by the Luftschiffbau Zeppelin company.
Construction of USS Shenandoah (ZR-1), 1923, showing the framework of a rigid airship
LZ 1, the first successful rigid airship
The extended Spiess airship in 1913
The British R34 in Long Island during the first ever return crossing of the Atlantic in July 1919
An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air.
A modern airship, Zeppelin NT D-LZZF in 2010
Dirigible airships compared with related aerostats, from a turn-of-the-20th-century encyclopedia
U.S. Navy airships and balloons, 1931: in the background, ZR-3, in front of it, (l to r) J-3 or 4, K-1, ZMC-2, in front of them, "Caquot" observation balloon, and in foreground free balloons used for training
The air-filled red balloon acts as a simple ballonet inside the outer balloon, which is filled with lifting gas.
