Tech Briefs
February 2002
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Sverdrup wind-tunnel tests for Olympic gold
 Sverdrup's Victor Canacci, left, and Lincoln DeWitt each hold a sled that underwent wind-tunnel testing. |
Blasting head-first down an ice track at speeds up to 129 km/h (80 mph) with periodic forces of 4.5 g is a 50-s rush for Lincoln DeWitt, but so is spending a day doing 30-s blocks of motionless body positioning atop a skeleton sled.
"We're trying to maximize his performance by quantifying with measurements for aspects like lift and drag force," said Victor Canacci, Driveability Test Facility (DTF) Wind Tunnel 8 Supervisor during DeWitt's aerodynamic evaluation day at the Sverdrup DTF in Allen Park, MI.
In October, engineers with Ford Motor Co. and Sverdrup conducted numerous human/sled wind-tunnel tests at speeds ranging from 48 to 113 km/h (30 to 70 mph). "Because we were looking at the (differences) between setups, the actual speed wasn't as much of a consideration as the consistency," said DeWitt. "The Sverdrup facility was able to keep the wind speed to within 0.2 km/h (0.1 mph) in all the tests we did."
Like vehicle wind-tunnel testing, data collection covered drag force, lift force, side force, pitching moment, rolling moment, and yaw. (Engineers used one of four pads—normally used for vehicle tire placements—as the testing surface for a sled stabilized in permanent position via brackets.)
"Testing with a human is a little more difficult than testing with a vehicle because the vehicle is stationary," said Oliver Leembruggen, Wind Tunnel Engineer. "Our data are typically taken over a 30-s time span, and to stay in one body position for 30 s is a long time." He noted that 300 constant condition data points were recorded every 1/10th of a second.
 Lincoln DeWitt remains motionless during a wind-tunnel test. |
DeWitt intends to represent the U.S. at the 2002 Olympics in Salt Lake City, UT, in the first skeleton sled competitions since the 1928 and 1948 Winter Games. The 34-year-old athlete, who took his first skeleton run in 1997, is ranked as the world's top skeleton racer.
DeWitt tested two sleds: a prototype and the steel-frame sled he rode to a World Cup title in 2001. A proven steel-frame sled supports a fiberglass pod. "The pod functions much like the suspension on a vehicle, but there's also an aerodynamic function on the bottom of the pod," said Chris Haerter, a former skeleton competitor and aeronautical engineer who served as DeWitt's technical consultant during wind-tunnel testing.
The sled's saddle keeps the torso in place, while 16-mm (5/8-in) stainless-steel runners with machined grooves (from sled midpoint to rear of sled) provide stability. "Each runner is bowed, which means only about 152 to 203 mm (6 to 8 in) of blade is in contact with the ice on a straightaway," said Haerter. Foam padding and gaffers tape complete the sled's material makeup.
Competition regulations outline specific sled size and configuration limitations. "For instance, you can't have holes in the sled, which would make it more aerodynamic," said Haerter. "It must be a flat sled at the front and the back. A frame/pod combination prototype sled is being tested here (DTF) that's two-thirds as thick as the sled (used to win the 2001 World Cup Championship)."
Engineers were focused on finding ways to improve DeWitt's sled time by determining an optimized body position, best sled design, and the best aerodynamic results relative to DeWitt's helmet and speed suit choices. "We did find gains in all areas," said DeWitt.
- Kami Buchholz
Solutia puts color in automotive glass
 The 2002 Porsche 911 Targa is the first production car to employ Solutia's Vanceva in the power-operated glass-sliding roof. |
Solutia recently launched Vanceva, a polyvinyl butyral (PVB) pigmented interlayer that is sandwiched between glass sheets to extend exterior vehicle color to side windows and sunroofs. "The pigment is integral to the product," said Thomas Laboda, Automotive Market Development Manager-Films for Solutia, Inc., in Troy MI. "It's color particles inside the PVB vs. spraying a dye onto the PVB."
 Color and patterns illustrate the future of the Vanceva brand. |
Various concept vehicles, including those displayed by General Motors' at the North American International Auto Show in Detroit, showcased Solutia's newest family of products. "Vanceva is one way for automakers to really differentiate a vehicle or an entire product line—like brown glass for one brand line and gray glass for another brand line," said Laboda. "It's a color option with all the benefits of laminated glass: more intrusion resistance than standard tempered glass as well as noise reduction and ultraviolet protection."
Color paired with patterns represents another product option. "By adding a PET (polyethylene terephthalate) with a printed pattern sandwiched between the PVB, you can then start adding geometric shapes, logos, or embossing to add depth to the glass," said Laboda.
 Side window on SUV shows Vanceva's potential. |
"There are opportunities in roof glass applications," said Jay Pyper, Market Development Director for Solutia's Performance Films. "For example, a glass laminated sunshade that has a yellow pattern visible through the glass seen from the vehicle's interior and a green pattern visible through the glass seen from the vehicle's exterior."
- Kami Buchholz
