GM Adds Small-Scale Wind Tunnel

General Motors Co. has opened a new reduced-scale wind tunnel at its Technical Center in Warren, Mich. The $30 million expansion will allow the carmaker to test clay models that are 40% the size of a production vehicle, which GM says will allow it to accelerate and verify aerodynamic efficiency earlier in the development process.

GM also plans to overhaul its full-size wind tunnel, which was built on the Warren campus in 1980. It will use Lockheed Martin’s wind tunnel in Atlanta, Ga., while the upgrades are made next year.

The new reduced-scale wind tunnel is powered by a 1,100-hp variable speed AC induction motor. A conveyor-style rolling ground plane simulates real-world highway driving conditions at wind speeds as high as 155 mph. Such high wind speeds allow GM to calculate a full-size vehicle’s coefficient of drag with a reduced-scale model.

Advanced 3-D printers are used to create detailed underbodies and engine blocks for the small clay models. Working suspensions with spinning wheels allow aerodynamic engineers to better examine how airflow affects a vehicle’s underbody while in motion, the carmaker notes.

GM says aerodynamic improvements are among the lowest cost ways to improve fuel economy and will be a key part of the company’s strategy to meet strict U.S. regulations for 2025. Replacing traditional exterior-side rearview mirrors with rearview cameras, for example, could boost highway fuel economy by as much as 2 mpg, according to the company.

On average, GM says, the aerodynamics of its vehicles has improved by 33% since the full-size wind tunnel was opened 35 years ago. Its slipperiest model to date is the 2016 Chevrolet Volt, which has a drag coefficient of 0.28.