Moffett Field airship hangars

There are three historic airship hangars at Moffett Field, in Mountain View in the southern San Francisco Bay Area, California. Hangar One (built 1931/2) is based on a structure of steel girders, while Hangars Two and Three (built 1941/2) are of wood. They are among the world's largest freestanding structures.

Hangar One
Hangar One was originally built in the 1930s to house US Navy rigid airships, the USS Macon (ZRS-5) in particular. It is 200 ft tall and covers 8 acre.

Hangars Two and Three
Moffett Field's Hangars Two and Three were built at the beginning of World War II for a program of coastal defense. They are still among the world's largest freestanding unsupported wood structures.

1940
In 1940, the US Navy proposed to the US Congress the development of a lighter-than-air station program for anti-submarine patrolling of the coast and harbours. This program proposed the construction of new stations in addition to the expansion at Naval Air Stations (NAS) M and Lakehurst.

The original contract was for steel hangars rather than wooden ones, 960 ft long, 328 ft wide and 190 ft high. Included at each site were helium storage and service, barracks for 228 men, power plant, landing apron, and a mobile mooring mast.

1941
The Second Deficiency Appropriation Bill for 1941, passed on 3 July 1941, introduced strict control of strategic materials like steel causing a change in construction material to wood. Standardized plans were drawn up by the Navy Department Bureau of Yards and Docks, with Arsham Amirikian acting as principal engineer.

1942
Hangars Two and Three at Moffett Field are 1075 ft long, 297 ft wide and 171 ft high, with an extruded parabolic form that reflected the profile of the airship vessels to be accommodated. A total of 51 Douglas Fir heavy-timber trusses resting on concrete bent frames contain the two-story shop and office areas. Two concrete and wood post and lintel structures support 121 ft high multi-track rolling doors at either end.

1943
A total of 17 wooden hangars were commissioned by the Navy Department Bureau of Yards and Docks in 1943, including those at NAS Lakehurst (2), NAS Moffett Field (2), NAS South Weymouth (1), NAS Weeksville (1), NAS Glynco (2), Naval Lighter Than Air Station Richmond (3), NAS Houma (1), NAS Hitchcock (1), Naval Lighter-Than-Air Station Santa Ana (2) and NAS Tillamook (2), with each hangar accommodating six airships.

Present day
Seven of the original seventeen wooden hangars still exist in the U.S.: Moffett Field (2), Tustin, California (2), Tillamook, Oregon (1), and Lakehurst, New Jersey(2).

These hangars have a monumental presence, and the Moffett Field pair, set within a paved expanse of the airfield, are a familiar landmark in the San Francisco Bay Area.

Popular culture
An episode of the Discovery Channel TV show MythBusters used one these hangars to disprove the myth that it is not possible to fold a sheet of paper in half more than seven times. The sheet of paper covered nearly the full width of the airship hangar. Other episodes of Mythbusters have utilized the hangar to test myths such as "Inflating a football with helium allows longer kick distances" and "Airworthy aircraft can be constructed of concrete."