What is an Airship?
An airship is any powered, steerable aircraft that it is inflated with a gas that is lighter than air.
What is a Dirigible?
“Airship” and “dirigible” are synonyms; a dirigible is any lighter-than-air craft that is powered and steerable, as opposed to free floating like a balloon.
The word “dirigible” is often associated with rigid airships but the term does not come from the word “rigid” but from the French verb diriger (“to steer”).
A blimp (technically a “pressure airship”) is a powered, steerable, lighter-than-air vehicle whose shape is maintained by the pressure of the gases within its envelope.
A blimp has no rigid internal structure: If a blimp deflates, it loses its shape.
Today, blimps are best known as advertising vehicles — Goodyear began using blimps to advertise their brand in 1925 — but blimps have also played an important role in the armed forces of many countries; the U.S. Navy’s lighter-than-air program made extensive use of blimps, primarily in anti-submarine and reconnaissance roles, from the 1920s through the 1950s.
Was the Hindenburg a Blimp?
No, the Hindenburg is often called “blimp” but that is not correct; Hindenburg was a rigid airship that maintained its shape by means of a metal framework.
What is a Rigid Airship?
A rigid airship has a framework surrounding one or more individual gas cells, and maintains its shape by virtue of the framework and not from the pressure of its lifting gas.
This photograph of the U.S. Navy airship Shenandoah under construction illustrates the ship’s metal framework, a partially inflated gas cell, and the fabric outer covering that protected the gas cells and provided aerodynamic streamlining:
This drawing of U.S.S. Shenandoah illustrates the various parts of a rigid airship:
What is a Zeppelin?
A zeppelin is a rigid airship manufactured by a particular company, the Luftschiffbau Zeppelin of Germany (the “Zeppelin Airship Construction Company”), founded by Count Ferdinand von Zeppelin.
Ferdinand von Zeppelin is considered the father of the rigid airship, but not all rigid airships are “zeppelins,” just as not all photocopiers are “Xerox” machines.
The term zeppelin is often associated with the German airships that conducted bombing raids during World War I, but while most of these ships were built by the Zeppelin Company, not all German WWI airships were zeppelins; the German military also used rigid airships of very different design built by the Schutte-Lanz and Parseval companies.
One of history’s most famous zeppelins was LZ-129 Hindenburg. (“LZ” stands for “Luftschiff Zeppelin” and “129” indicates that Hindenburg was the 129th airship designed by the Zeppelin Company.) Because the American naval ships USS Akron and USS Macon were built by a Goodyear-Zeppelin joint venture, they are sometimes referred to as zeppelins as well.
Zeppelins still fly today; in fact the new Goodyear airship is a not a blimp but a zeppelin, built by a descendant of the same company that built Graf Zeppelin and Hindenburg.
What is a Semi-Rigid Airship?
A semi-rigid airship, like a blimp, maintains its aerodynamic shape from internal gas pressure, but it has a partial rigid frame, usually in the form of a keel, which supports and distributes loads and provides structural integrity during maneuvering.
Famous semi-rigid airships include Norge of polar explorer Roald Amundsen and Italia of Umberto Nobile. The modern Zeppelin NT is also a semi-rigid airship.