Flettner helicopter in the wind tunnel at Chalais-Meudon
Flettner helicopter in the wind tunnel at Chalais-Meudon
This photograph shows a Flettner helicopter being tested in the wind tunnel at Chalais-Meudon, near Paris. It was taken around 1941. During the German occupation of France, the Aerodynamic Research Institute (Aerodynamische Versuchsanstalt; AVA) operated the large wind tunnel on behalf of the Reich Ministry of Aviation.
Credit: © DLR. All rights reserved