INSIDE A WIND TUNNEL: ONERA'S S1CH
Panoramas of ONERA's historic wind tunnel, by photographer Laurent Thion.
by Michelle Bienias
Paris-based photographer Laurent Thion, of www.ecliptique.com, recently photographed ONERA’s S1Ch Wind Tunnel, which was the biggest in France until the end of WWII. Iit was here that planes such as the Caravelle and Concorde were tested, as well as the first 'delta wing' airplane cars and the Volkswagen. French skiing champion Jen-Claude Killy also used the wind tunnel.
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Although this tunnel is no longer in use, it was recently saved from destruction and is now classified as an historic building. This wind tunnel was built between 1932 and 1934 and it made possible the testing of a real plane of 12m, with ignited engine and pilot on board. The wind tunnel is 120m in length and 25m high. ONERA (Office National d’Etudes et de Recherches Aérospatiales) is the French national aerospace research establishment, headquartered in Chatillon, near Paris. It is one of the key players in the global aerospace research community, operating a large range of specialized research facilities and participating in many EU-supported projects under various Framework Programmes.  What is a wind tunnel? Wind tunnels date back to the 1870's when scientists realized it didn't matter if an object was stationary and air was blown over it or if the object were moving through the air as the resultant forces over the object would be the same. The idea of blowing air over an object and determining the forces led to the invention of the wind tunnel. When an aircraft moves through calm air, its aerodynamic behavior is the same as if it were immobile and the air was rushing past it. A wind tunnel is a test facility used to generate a flow of air past a scaled model of an aircraft. It provides various measurements to determine aerodynamic behavior and performance. In that respect a wind tunnel can be seen as an ‘aerodynamic flight simulator’. Although actual flight-testing is more realistic, the advantages of the wind tunnel are obvious. Wind tunnel testing can be performed at an early stage in an aircraft development program without having to wait for the first prototype. The costs are clearly lower and the risks, both technical and safety-related, are far less severe than those associated with a real flight test. A wind tunnel can provide intermittent or continuous airflow, running from as little as a fraction of a second to several hours, and at high or low speeds to simulate take off and landing conditions or cruise conditions. It can be of the open circuit type where the airflow leaving the tunnel does not re-enter the circuit or of the closed circuit type where the same air is re-circulated. Finally, it can be pressurized, or can operate under normal atmospheric pressure. Laurent Thion’s Shoot Details:
These six panoramas where shot in two days during January 2004 with a Coolpix 5000 + wc+e68 and homemade head and then assembled with Stitcher 3.5.The biggest difficulty with the shoot was the light, which was very high contrast because there were very few windows in relation to the size of the room. All pictures were bracketed three or four times with different exposure times and were assembled with Photoshop. The most difficult shot was the ‘Command Center’ as it was a very small, long room and the fluorescent light was close to the ceiling. More 5 EV between highlight and shadow. I left the ceiling a little too light to keep it realistic. The other problem area was the ‘Experiment Room’: The floor is a large balance and the tripods take some degree in each direction where I was around. But fortunately, the stitching is ok. On these panos, note the contrast between the sun on the round wall and the black anechoic facing.
Email: Laurent-thion@ecliptique.com
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