Charlie MageeAutomobile and Driver
From the December 2021 challenge of Automobile and Driver.
Understanding how automobiles transfer by means of air is essential to automotive design. Wind tunnels, rooms with a managed airflow to assist measure and visualize aero motion, have been round for greater than a century. Automakers have elevated their measurement and added a rolling highway (a treadmill-like ground) in an try to copy real-world motion. However a lab is, and at all times shall be, a stand-in for the true factor.
Rob Lewis, an aerodynamicist who has labored on Formulation 1 automobiles and Olympic bicycles, is a founding father of TotalSim, a computational-fluid-dynamics firm within the U.Okay. He was annoyed by the restrictions and prices of the tunnel amenities, discovering them to be outdoors the working budgets of most small corporations and racing groups. Testing at such locations might rack up $50,000 a day in rental charges, in keeping with Lewis. “I believed, what are the alternate options?” he says. Lewis had a imaginative and prescient for a wind tunnel that took the perfect elements of the lab—repeatability, a climate-controlled atmosphere—however price much less and allowed for extra sensible driving experiences. His answer? An enormous gap, or, slightly, an precise tunnel.
Lewis began trying round England for an unused railroad tunnel the place he might take a look at a automobile on an actual highway but management variables. It wanted to be straight, extensive sufficient to do some dynamic testing, and have ample size so a car at velocity can be inside lengthy sufficient to generate helpful information. Conveniently, the web loves deserted locations. Lewis says he had the concept and 10 minutes later discovered an internet site devoted to rail sites that have fallen out of use.
Catesby Tunnel, close to the English city of Daventry, opened in 1898. The Victorian tunnel closed 68 years later when practice traces modified. It’s 1.7 miles lengthy, lifeless straight, and rises at a relentless 0.57 % grade. When Lewis discovered the tunnel, it was flooded and overgrown. Now, with a freshly laid asphalt floor instead of its authentic tracks, it’s going into service as an aerodynamics lab that can enable a automobile to maneuver by means of air slightly than sit nonetheless within the wind. Speeds shall be restricted to automobiles’ capabilities with a watch to security. Lewis reckons that race automobiles shall be doing as much as 200 mph, nevertheless it’s not nearly high speeds.
“We will do acoustic testing,” Lewis says. “Perhaps I’ve obtained 4 [side] mirror designs, and I wish to take heed to these and see which is noisiest.” He’d line the tunnel with sound-deadening panels and arrange a microphone array—no chicken noise, no wind interference. Wish to run an SUV to see the place the filth builds up on a wet day? “Put a moist marker fluid on the highway, drive by means of, clear it off, change the mud flap design, and do it once more. So you have obtained extra actuality with out sacrificing repeatability.”
TotalSim is not the primary to do that. Chip Ganassi Racing makes use of a retired Pennsylvania Turnpike tunnel to review, amongst different issues, multiautomobile aerodynamics at velocity, one thing nearly inconceivable to do in a standard wind tunnel. Catesby is prone to see comparable actions from lots of the U.Okay.’s racing groups. However what about that outdated chestnut of aero nerds—can a high-downforce automobile actually drive the other way up? Perhaps, says Lewis, however not at Catesby: “It has a diameter of 27 ft. Even at that radius, the partitions are usually not flat. Additionally, we might should reline the roof of the tunnel or the suction beneath the automobile may begin pulling bricks out.”
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