Editing Gustave Eiffel (section)

== Later career ==
[[File:Gustave Eiffel 1910.jpg|thumb|left|Eiffel in 1910]]
After his retirement from the Compagnie des Etablissements Eiffel, Eiffel went on to do important work in [[meteorology]] and [[aerodynamics]].<ref name="flightglobal1924">[http://www.flightglobal.com/pdfarchive/view/1924/1924%20-%200004.html "The Death of a Great Pioneer: Gustav Eiffel Passes Away"]. ''[[Flight International]]''. 3 January 1924</ref>  Eiffel's interest in these areas was a consequence of the problems he had encountered with the effects of wind forces on the structures he had built.

His first aerodynamic experiments, investigating the air resistance of surfaces, were carried out by dropping the surface to be investigated together with a measuring apparatus down a vertical cable stretched between the second level of the Eiffel Tower and the ground. Using this Eiffel definitely established that the air resistance of a body was very closely related to the square of the airspeed. He then built a laboratory on the Champ de Mars at the foot of the tower in 1905, building his first [[wind tunnel]] there in 1909. The wind tunnel was used to investigate the characteristics of the [[airfoil]] sections used by the early pioneers of aviation such as the [[Wright Brothers]], [[Gabriel Voisin]] and [[Louis Blériot]]. Eiffel established that the lift produced by an airfoil was the result of a reduction of air pressure above the wing rather than an increase of pressure acting on the under surface. Following complaints about noise from people living nearby, he moved his experiments to a new establishment at [[Auteuil, Paris|Auteuil]] in 1912. Here it was possible to build a larger wind tunnel, and Eiffel began to make tests using scale models of aircraft designs.<ref>Granet, André. [https://web.archive.org/web/20130525182115/http://www.gustaveeiffel.com/Ses_ouvrages/Laboratoire_aerodynamique_Eiffel.html 1912 : LABORATOIRE AERODYNAMIQUE EIFFEL]. Laboratories Eiffel.</ref>
In 1913 Eiffel was awarded the [[Langley Gold Medal|Samuel P. Langley Medal for Aerodromics]] by the [[Smithsonian Institution]]. In his speech at the presentation of the medal, [[Alexander Graham Bell]] said:<ref>Harvie 2006, p. 207</ref>{{blockquote|text=...his writings upon the resistance of the air have already become classical. His researches, published in 1907 and 1911, on the resistance of the air in connection with aviation, are especially valuable. They have given engineers the data for designing and constructing flying machines upon sound, scientific principles }}
Eiffel had meteorological measuring equipment placed on the tower in 1889, and also built a weather station at his house in [[Sèvres]]. Between 1891 and 1892 he compiled a complete set of meteorological readings, and later extended his record-taking to include measurements from 25 different locations across France.
<!-- (chunk to have a home found for it) and suggested that the military install radio equipment atop the tower. In the following years it continued to serve as a permanent radio tower, and eventually for television broadcasting.<ref>[https://web.archive.org/web/20051217075256/http://www.tour-eiffel.fr/teiffel/uk/documentation/dossiers/page/gustave_eiffel.html "Gustave Eiffel"]. tour-eiffel.fr.</ref> -->

Eiffel died on 27 December 1923, while listening to Beethoven's 5th symphony ''andante'', in his mansion on [[Rue Rabelais]] in Paris. He was buried in the family tomb in [[Levallois-Perret Cemetery]].