Rigid airship

Rigid airship

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http://en.wikipedia.org/wiki/Rigid_airship

Construction of USS Shenandoah (ZR-1), 1923, showing the framework of a rigid airship.

A rigid airship was a type of airship in which the envelope retained its shape by the use of an internal structural framework rather than by being forced into shape by the pressure of the lifting gas within the envelope as used in blimps and semi-rigid airships.

Rigid airships were produced and relatively successfully employed from the beginning of the 1900s to the end of the 1930s, but their heyday ended when the Hindenburg ignited on May 6, 1937.

Terminology

Although "rigid airship" is the proper formal term, these aircraft are often referred to in casual use by several other names such as dirigibles, zeppelins (after the most successful ships of this type built by the Zeppelin Company) or the big rigids.

Early days

By 1874 several people had conceived of a rigid dirigible (in contrast to non-rigid powered airships which had been flying since 1852). Frenchman Joseph Spiess had published a rigid airship proposal in 1873 but failed to get funding. Count Zeppelin had outlined his thoughts of a rigid airship in diary entries from 25 March 1874 through to 1890 when he resigned from the military. David Schwarz had thought about building an airship in the 1880s and had likely started design work in 1891, definitely by 1892 he was starting construction. It was not until after Schwarz's death in 1897 that his all-aluminium airship, built with help from with Carl Berg and the Prussian Airship Battalion, was test flown. Schwarz and Berg had an exclusive contract and Count Zeppelin was obliged to come to a legal agreement with Schwarz's heirs to obtain aluminium from Carl Berg, although the two men's designs were different and independent from each other. With Berg's aluminum, Zeppelin was able in 1899 to start building and, in 1900 July, to fly the Zeppelin LZ1.

Great Britain

Great Britain and the USA lagged behind Germany in rigid airship technology. According to a 2001 PBS documentary, much of Britain's knowledge was based on reverse engineered technology from World War I German zeppelin crashes. After several crashes of experimental airships, the British ceded this field to the Germans.

France

France's only rigid airship was built by Alsation Joseph Spieß using a wooden framework and it flew on 1913-04-13. It was 146 metre long, with a diameter of 13.5 metre and a gas volume of 16,400 cubic metres.

Germany

In 1900, Count Ferdinand von Zeppelin began trials with a rigid airship based on the theories of Austrian engineer David Schwartz. Germany had over twenty very large lighter-than-air rigid airships by the beginning of World War I. Zeppelin’s company owned seven of them. His airline carried 32,722 passengers in the five years before the war over 1,588 flights totaling 107, 205 miles. The German war ministry took over two of them in 1909 and one of them crashed. Commercial airlines ended in Germany at the outbreak of the war. During the war, Zeppelin’s company built 95 giant military airships. The German military airship stations had been established before the war. On September 2-3, 1914, the Zeppelin LZ 17 dropped three 200lb bombs on Antwerp. On January 19, 1915, two German airships dropped bombs on Norfolk, England, killing numerous people, but the third ship in the air raid returned to Germany with engine trouble before reaching England. On May 31, 1915, the first bombs fell on London. The night of September 2-3, 1916 was when the first German airship was shot down over English soil. It was done using a small heavier-than-air aircraft. The night of November 27-28, 1916, a German winged aircraft dropped bombs on London. The build-up of England’s defenses against such aircraft lead to the discontinuation of airship raids on England. The last to cause casualties occurred on April 12, 1918.

United States

The United States rigid airship program was mostly stationed in Lakehurst Naval Air station, New Jersey. The ZR-1 Shenandoah was one of the first, serving from 1923 to 1925. The ZR-2 was a British airship intended to join the naval fleet, but it crashed in 1921. The ZR-3 was a German airship, sold to the United States in 1924 and named Los Angeles. The ship was grounded in 1931, due to the Depression, but was not dismantled for over 5 years. The sister ships Akron and Macon both crashed after technical failure. These crashes ended the rigid airship program.

Production

As well as the Zeppelin Company, Schütte-Lanz also manufactured them. Both America and Britain have manufactured rigid airships at some point.

Some famous rigid airships

R34, British airship and the first aircraft to traverse the Atlantic Ocean from east to west, in 1919.
USS Shenandoah, American naval airship which served the U.S. Navy from 1923 until its crash in Ohio in 1925.
R38 (ZR-2), British airship intended to join the American naval fleet, but crashed during testing in 1921.
USS Los Angeles, German airship sold to the United States in 1924 as part of German reparations from World War I. The ship served with distinction from 1924 to 1931.
LZ 127 Graf Zeppelin, German passenger airship designed and piloted by Hugo Eckener. It circumnavigated the globe in 1929 and had a spotless safety record. It was ultimately dismantled by the Nazis at the outset of World War II.
R-100, British airship built by the Airship Guarantee Company, a private company created solely for the construction of this airship, as a subsidiary of the armaments firm, Vickers.
R-101, British airship designed and built by the British government in a kind of competition with the R-100. The R-101 crashed on its maiden flight in 1930 in France, with considerable loss of life. Its crash effectively ended British participation in rigid airship construction.
USS Akron, American naval airship designed and built by the Goodyear Tire and Rubber Company in Ohio in 1931. Deployed as an airborne aircraft carrier, it was lost at sea in a storm off New Jersey in 1933 with considerable loss of life.
USS Macon, sister ship to the Akron, it was a near carbon-copy of her. Though it suffered only 2 deaths, its crash in 1935 off the coast of California ended American participation in rigid airship development.
LZ 129 Hindenburg, German passenger airship also designed and built by Hugo Eckener. The airship was lost in a famous fire in New Jersey in 1937. With its end went the end of the age of the Great Rigid Airships.

Modern rigids

There are no rigid airships flying today. The Zeppelin company refers to their NT ship as a rigid but this is a misnomer. The envelope shape is retained in part by super-pressure of the lifting gas, and so the NT is more correctly classified as a semi-rigid.