Editing Wind tunnel (section)

=== Widespread usage ===
[[File:Messerschmitt Bf 109E wind tunnel testing at the Deutsche LFA.jpg|right|thumb|250px|Herman Goering tunnel A3 commissioned in 1940<ref name="AeroRsh">{{cite book | url=https://link.springer.com/book/10.1007/978-3-642-18484-0 |title=Aeronautical Research in Germany|author1=Hirschel, Ernst Heinrich |author2=Prem, Horst |author3=Madelung, Gero |page=194|ref=refAeroRsh2004}}</ref> showing open test section with [[Messerschmitt Bf 109]]F installed for testing.]]

Subsequent use of wind tunnels proliferated as the science of aerodynamics and discipline of aeronautical engineering were established and air travel and power were developed.

The US Navy in 1916 built one of the largest wind tunnels in the world at that time at the Washington Navy Yard. The inlet was almost {{convert|11|ft|m}} in diameter and the discharge part was {{convert|7|ft|m}} in diameter. A {{cvt|500|hp|kW}} electric motor drove the paddle type fan blades.<ref>{{Citation|url=https://books.google.com/books?id=V3fmAAAAMAAJ&pg=PA426|title=US Navy Experimental Wind Tunnel|year=1915 }}</ref>

In 1931 the NACA built a {{convert|30|by|60|ft|m|adj=on}} [[Full-Scale Wind Tunnel|full-scale wind tunnel]] at Langley Research Center in Hampton, Virginia. The tunnel was powered by a pair of fans driven by {{cvt|4000|hp|kW}} electric motors. The layout was a double-return, closed-loop format and could accommodate many full-size real aircraft as well as scale models. The tunnel was eventually closed and, even though it was declared a [[National Historic Landmark]] in 1995, demolition began in 2010.

Until World War II, the world's largest wind tunnel, built in 1932–1934, was located in a suburb of Paris, [[Chalais-Meudon]], France.{{Citation needed|date=December 2021|reason=The Popular Mechanics article in the next citation does not mention the name of the suburb nor that the wind tunnel is the largest.}}  It was designed to test full-size aircraft and had six large fans driven by high powered electric motors.<ref>{{Cite magazine |title=Man-Made Hurricane Tests Full-Sized Planes; Giant Battery of Fans Helps Makes Flying Safe |url=https://books.google.com/books?id=QdsDAAAAMBAJ&pg=PA94 |magazine=[[Popular Mechanics]] |date=19 January 1936 |pages=94–95|via=Google Books}}</ref> The Chalais-Meudon wind tunnel was used by [[ONERA]] under the name S1Ch until 1976 in the development of, e.g., the [[Sud Aviation Caravelle|Caravelle]] and [[Concorde]] airplanes. Today, this wind tunnel is preserved as a national monument.

[[Ludwig Prandtl]] was [[Theodore von Kármán]]'s teacher at [[Göttingen University]] and suggested the construction of a wind tunnel for tests of airships they were designing.<ref name=TvK>[[Theodore von Kármán]] (1967) ''The Wind and Beyond''</ref>{{rp|44}} The [[vortex street]] of turbulence downstream of a cylinder was tested in the tunnel.<ref name=TvK/>{{rp|63}} When he later moved to [[Aachen University]] he recalled use of this facility:

<blockquote>I remembered the wind tunnel in Göttingen was started as a tool for studies of Zeppelin behavior, but that it had proven to be valuable for everything else from determining the direction of smoke from a ship's stack, to whether a given airplane would fly. Progress at Aachen, I felt, would be virtually impossible without a good wind tunnel.<ref name=TvK/>{{rp|76}}</blockquote>

When von Kármán began to consult with [[Caltech]] he worked with [[Clark Millikan]] and Arthur L. Klein.<ref name=TvK/>{{rp|124}} He objected to their design and insisted on a return flow making the device "independent of the fluctuations of the outside atmosphere". It was completed in 1930 and used for [[Northrop Alpha]] testing.<ref name=TvK/>{{rp|169}}

In 1939 [[General Arnold]] asked what was required to advance the USAF, and von Kármán answered, "The first step is to build the right wind tunnel."<ref name=TvK/>{{rp|226}} On the other hand, after the successes of the [[Bell X-2]] and prospect of more advanced research, he wrote, "I was in favor of constructing such a plane because I have never believed that you can get all the answers out of a wind tunnel."<ref name=TvK/>{{rp|302–03}}