Daytona 500: Cutting the Wind

Laser scanner aids development of aerodynamic race cars

NASCAR regulations keep narrow engineering parameters for racing vehicles. Certain longitudinal and lateral cross-sections with tolerances between 0.070 and 0.5 in. dictate conformance to similar body shapes. However, with some races determined by 1/100th of a second difference in lap times, slight variance in wind-resistance can alter the outcome greatly. Advances in aerodynamics have allowed teams using wind tunnels to optimize body shapes for minimal wind-resistance within these tolerances.

Driver Bill Elliot with Dodge Intrepid

Since about a dozen copies of each racecar are produced each racing season, precise documentation of optimal shapes is critical. Manual plumbline measurements require much time and skill without much resolution, while mechanical digitizers offer little more. By using a laser scanner system, Dodge's redesign team at Evernham Motorsports, Statesville, NC, has cut the time invested in 3D measurements while increasing precision.

They use a ModelMaker system from NVision, Dallas, TX, that incorporates a 3D laser sensor, mechanical digitizer on which the sensor is attached, a PC and software that extracts, displays and manipulates data. The laser sensor is a single viewpoint stripe sensor, which projects a line of laser light onto a surface and captures multiple coordinates with a small CCD camera. Scanning an entire car body in 12 to 14 hours generates more than 25 million coordinates that are imported into detailed CAD drawings. Minor aerodynamic adjustments to the shape can then be precisely recorded by comparing subsequent scans to the original design. Then, if a desired prototype is damaged during road-tests, the data can be used for replications.

Laser scanner systems

Following an 18-year hiatus, Dodge made an impressive comeback at the 2001 Daytona 500, with the newly designed Intrepids gaining the first two starting positions in the qualifying races, while attaining four out of the 10 fastest times. Regarding his 183.565 mph lap, polesitter Bill Elliot comments, "It didn't feel that fast." This racing season 10 different NASCAR teams will use Evernham's design, with each team building between nine and 15 copies over the course of the season.

--SG

For more information:

Circle 703 - NVision Inc, or connect directly to their website via the Online Reader Service Program at http://www.OneRS.net/104df-703