Editing Wind tunnel (section)

===World War II===
In 1941 the US constructed one of the largest wind tunnels at that time at Wright Field in Dayton, Ohio. This wind tunnel starts at {{convert|45|ft|m}} and narrows to {{convert|20|ft|m}} in diameter. Two {{convert|40|ft|m|adj=on}} fans were driven by a {{cvt|40000|hp|kW}} electric motor. Large scale aircraft models could be tested at air speeds of {{convert|400|mph|km/h|abbr=on}}.<ref>{{Citation|url=https://books.google.com/books?id=mtkDAAAAMBAJ&pg=PA14|title=400mph Wind Tests Planes|date=July 1941 |publisher=Hearst Magazines }}</ref>

During WWII, Germany developed different designs of large wind tunnels to further their knowledge of aeronautics. For example, the wind tunnel at [[Peenemünde]] was a novel wind tunnel design that allowed for high-speed airflow research, but brought several design challenges regarding constructing a high-speed wind tunnel at scale. However, it successfully used some large natural caves which were increased in size by excavation and then sealed to store large volumes of air which could then be routed through the wind tunnels. By the end of the war, Germany had at least three different supersonic wind tunnels, with one capable of Mach 4.4 heated airflows.

A large wind tunnel under construction near [[Oetztal]], Austria would have had two fans directly driven by two {{cvt|50,000|hp|kW}} [[hydropower|hydraulic turbines]]. The installation was not completed by the end of the war and the dismantled equipment was shipped to [[Modane]], France in 1946 where it was re-erected and is still operated there by the [[ONERA]]. With its {{convert|8|m|ft|order=flip|adj=on}} test section and airspeed up to Mach 1, it is the largest transonic wind tunnel facility in the world.<ref name=EH04>[[#refAeroRsh2004|Aeronautical Research (2004)]], p.87.</ref> [[Frank Wattendorf]] reported on this wind tunnel for a US response.<ref>{{cite journal | author1=Wattendorf, F.L.| date=May 1946| title=Reports on selected topics of German and Swiss aeronautical developments|url=https://www.governmentattic.org/TwardNewHorizons.html|journal=Toward New Horizons|format=Governmentattic}}</ref>

On 22 June 1942, Curtiss-Wright financed construction of one of the nation's largest subsonic wind tunnels in Buffalo, New York. The first concrete for building was poured on 22 June 1942 on a site that eventually would become [[Calspan]], where the wind tunnel still operates.<ref>{{cite web|url=https://calspan.com/company/history |title=Calspan History > Wind Tunnel Construction |publisher=calspan.com |access-date=2015-04-23}}</ref>

By the end of World War II, the US had built eight new wind tunnels, including the largest one in the world at Moffett Field near Sunnyvale, California, which was designed to test full size aircraft at speeds of less than {{cvt|250|mph|kph}}<ref>{{Citation|chapter-url=https://books.google.com/books?id=TCEDAAAAMBAJ&pg=PA66|chapter=Wind at Work For Tomorrow's Planes|title=Popular Science|date=July 1946|pages=66–72|publisher= Hearst Magazines}}</ref> and a vertical wind tunnel at Wright Field, Ohio, where the wind stream is upwards for the testing of models in spin situations and the concepts and engineering designs for the first primitive helicopters flown in the US.<ref>{{Citation|chapter-url=https://books.google.com/books?id=AyEDAAAAMBAJ&pg=PA73|chapter= Vertical Wind Tunnel|date= February 1945|title=Popular Science|publisher= Hearst Magazines}}</ref>