The 'Astra-Torres airships' were non-rigid airships built by
Société Astra to a design by Spaniard
Leonardo Torres Quevedo in France between about 1908 and 1922. They had a highly-characteristic tri-lobed cross-section rather than the more usual circular cross-section. This was the result of moving most of the blimp's bracing wires inside the envelope in an attempt to minimise drag. Early Astra-Torres airships could be trimmed by moving the entire gondola fore-and-aft.
Astra-Torres airships were used by the
French Navy during
World War I and for a few years before and after. A few of these were transferred to the American expeditionary forces in Europe, and
AT-1,
AT-13, and
AT-17 were eventually taken back to the United States.
Britain's
Royal Navy purchased AT-14, AT-17, and AT-19, these becoming
HMA No. 3,
HMA No. 8, and
HMA No. 16 respectively. All were taken out of service in May 1916, although the Astra-Torres design was imitated in Britain's own
Coastal class airships that served through to the end of the War.
After the war, AT-16 was operated by
Transaérienne, carrying sightseeing passengers over Paris, and AT-24 was purchased by the Japanese Navy.
References
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Jane's Encyclopedia of Aviation, , Michael J. H., Taylor, Studio Editions, 1989,