Editing USS Shenandoah (ZR-1) (section)

==Design and construction==
[[File:Zeppelin L 49.jpg|thumb|left|L-49/LZ-96, the airship that would serve as the basis for ''Shenandoah'']]

''Shenandoah'' was originally designated FA-1, for "Fleet Airship Number One" but this was changed to ZR-1. The airship was {{convert|680|ft|m|2|abbr=on}} long<ref name="p64">Hayward (1978) p. 64</ref> and weighed 36 tons (32,658 kg). It had a range of {{convert|5000|mi|nmi km|lk=on|abbr=on}}, and could reach speeds of {{convert|70|mph|kn km/h|lk=out|abbr=on}}. ''Shenandoah'' was assembled at [[Joint Base McGuire–Dix–Lakehurst|Naval Air Station Lakehurst]], New Jersey in 1922–1923, in Hangar No. 1, the only hangar large enough to accommodate the ship; its parts were fabricated at the [[Naval Aircraft Factory]] in Philadelphia. NAS Lakehurst had served as a base for Navy blimps for some time, but ''Shenandoah'' was the first rigid airship to join the fleet.
[[File:Shenandoah controls.jpg|left|thumb|1923 photo of the airship control gondola of USS ''Shenandoah''. Commander McCrary, the ship's commander, is shown at the wheel. Called "Empress of the Clouds"<ref>{{Cite web|url=https://upload.wikimedia.org/wikipedia/commons/archive/8/8d/20141123185616%21Shenandoah_controls.jpg|title=Photo of the control gondola of the US airship Shenandoah. Commander McCrary, the ship's commander, is shown at the wheel.|date=23 November 2014|website=Wikipedia Commons|access-date=13 April 2017}}</ref>]]
The design was based on captured [[List of Zeppelins#LZ 96|Zeppelin bomber ''L-49'' (LZ-96)]], built in 1917.<ref name="proceedings">Hayward (1978) p. 62</ref><ref>Swanborough, G. and Bowyers, P. M. ''United States Navy Aircraft Since 1912''. London: Putnam, 1976 (2nd ed.) {{ISBN|0 85177 838 0}}, p. 586</ref> ''L-49'' was a lightened Type U "height climber", designed for altitude at the expense of other qualities. The design was found insufficient and a number of the features of newer Zeppelins were used, as well as some structural improvements.<ref name="proceedings"/> The structure was built from a new alloy of aluminum and copper known as [[duralumin]], supplied by [[Alcoa]]. Girders were fabricated at the Naval Aircraft Factory.<ref name="p64"/><ref name="wt">{{cite book |last1=Trimble |first1=William |title=Wings for the Navy: a history of the Naval Aircraft Factory, 1917-1956 |date=1990 |publisher=United States Naval Institute |location=Annapolis |isbn=9780870216633 |pages=56–59}}</ref><ref>{{cite book |last1=Smith |first1=Richard |title=The Airships Akron & Macon, The Flying Aircraft Carriers of the United States Navy |date=1965 |publisher=Naval Institute Press |location=Annapolis, Maryland |isbn=0870210653 |page=178}}</ref> Whether the changes introduced into the original design of ''L-49'' played a part in ''Shenandoah''{{'}}s later breakup is a matter of debate. An outer cover of high-quality cotton cloth was sewn, laced or taped to the duralumin frame and painted with aluminum [[Aircraft dope|dope]].<ref name="p64"/>

The gas cells were made of [[goldbeater's skin]]s, one of the most gas-impervious materials known at the time.<ref name="proceedings"/> Named for their use in beating and separating gold leaf,<ref name="proceedings"/> goldbeater's skins were made from the outer membrane of the large intestines of cattle.<ref name="proceedings"/> The membranes were washed and scraped to remove fat and dirt, and then placed in a solution of water and glycerine in preparation for application to the rubberized cotton fabric providing the strength of the gas cells.<ref name="proceedings"/> The membranes were wrung out by hand to remove the water-glycerine storage solution and then rubber-cemented to the cotton fabric and finally given a light coat of varnish.<ref name="proceedings"/> The 20 gas cells within the airframe were filled to about 85% of capacity at normal barometric pressure.<ref name= "p63">Hayward (1978) p. 63</ref> Each gas cell had a spring-loaded relief valve and manual valves operated from the control car.<ref name="p64"/>

===Pioneer of helium-filled rigids===
As the first rigid airship to use [[helium]] rather than [[hydrogen]], ''Shenandoah'' had a significant edge in safety over previous airships. Helium was relatively scarce at the time, and ''Shenandoah'' used much of the world's reserves just to fill its {{convert|2100000|ft3|m3}} volume.<ref name="p64"/> {{USS|Los Angeles|ZR-3|2}}—the next rigid airship to enter Navy service, originally built by ''[[Luftschiffbau Zeppelin]]'' in Germany as ''LZ 126''—was at first filled with the helium from ''Shenandoah'' until more could be procured.

''Shenandoah'' was powered by {{convert|300|hp|kW|abbr=on}}, eight-cylinder [[Packard]] gasoline engines. Six engines were originally installed, but in 1924 one engine (aft of the control car) was removed. The first frame of ''Shenandoah'' was erected by 24 June 1922; on 20 August 1923, the completed airship was floated free of the ground. Helium cost $55 ({{Inflation|US|55|1922|2019|fmt=eq}}{{Inflation/fn|US|2019}}) per thousand cubic feet at the time, and was considered too expensive to simply vent to the atmosphere to compensate for the weight of fuel consumed by the gasoline engines.<ref name="p67"/> Neutral buoyancy was preserved by installing condensers to capture the water vapor in the engine exhaust.<ref name="p67"/>