The assignment for college teams was to design, develop, and fabricate an open-wheeled, open-cockpit racecar for competition. And even if the outcome for many teams fell short of the glory associated with a top finish or one of the technical achievement awards, the hundreds of student engineers competing at Formula SAE 2008 were anything but downbeat.
During the engineering design judging event—one of several static evaluations that served as a prelude to a series of dynamics events—a second-year team’s racecar was in one of the review rings, a temporary staging zone inside a speedway garage. After removing the racecar’s body panels, judges lingered over the racecar’s dual 10-in (255-mm) radiator fans and the aluminum sheet-metal radiator ducting that channeled air from the radiator that was positioned behind the driver’s seat.
“We’re running the hottest part of the car, the exhaust, next to what should be the coolest part of the car, the radiator. The judges had design concerns, but we feel our reasoning is justified because of the heat-shielding that surrounds the exhaust,” said Cooper Union co-team leader Shiann Yamin, a graduate mechanical engineering student studying at the private college in New York. “During dynamometer testing, we were running the engine hard for six hours. And just with the fans on, we didn’t overheat.”
Other than the steering wheel, no other part of the Cooper Union racecar was a carryover from the college’s 2007 FSAE entry. “The frame was a major changeover. It was designed to fit taller drivers in a more comfortable seating position, and that led to the car’s components being arranged within much tighter packaging constraints,” said Yamin.
Cooper Union’s racecar had a mass of 564 lb (256 kg)—significantly heavier than Australia’s Royal Melbourne Institute of Technology (RMIT) racecar, the winner of the FEV powertrain award. “RMIT used a very fuel-efficient combination of a single-cylinder Yamaha WR450 engine with electronic fuel injection, a Yamaha four-speed gearbox, and a carbon-fiber monocoque body to achieve a total vehicle mass of about 330 lb [150 kg]; 450 to 500 lb [204 to 227 kg] would be a typical number. The vehicle had excellent acceleration and the best score in the field for fuel economy,” said Robert Last, Vice President of Operations and Communications for FEV, Inc.
Seven-year FSAE engineering design judge Andrew Randolph, Engine Technical Director for Earnhardt Childress Racing in North Carolina, said teams that hit the bulls-eye in terms of powertrain, suspension, chassis, ergonomics, innovation, design, and content have had ample competition experience. But even for the teams that missed the mark, there was a valuable payoff. “They’re learning," he said. "Without a doubt, design optimization is an iterative process that requires most teams several years to develop. The rules state that a given car can only be used for two years, thus it is essential to apply past lessons learned to newer designs.”
Wichita State University’s racecar dropped about 30 lb (14 kg) from last year’s FSAE West competition in California. “For a modified first-year car, reaching 481 lb is a great accomplishment,” said team leader Benjamin Martin. In addition to using aluminum for the body, Martin and his crew increased the car's power from 56 to 62 hp (42 to 46 kW). “That was accomplished mostly by changes to the air-box. We smoothed out the airflow on the intake ports as well as the throttle body,” Martin explained.
Plans for next year include transforming the now-wingless racecar into a ground hugger via front and rear carbon-fiber/aluminum-insert wings. “We’ll test the wings in the wind tunnel this summer,” said Martin.
Louisiana State University’s 2008 racecar was supposed to feature a micro heat exchanger instead of a stock radiator. “We weren’t able to use the unit at this year’s competition because there wasn’t enough time to custom-make a filler neck after we realized we needed one,” said LSU team member Mariana Hurtado, who designed and hand-assembled the unit’s 6000 stainless-steel tubes. The 8.125-in (206-mm) tubes were arranged in a corrugated pattern inside an aluminum housing that is about 11 in (279 mm) tall, 6.4 in (163 mm) wide, and 3.5 in (89 mm) deep.
“We tested the micro heat exchanger in the car and it performed better than we anticipated. Right now, this unit is 50% smaller in the frontal area than the stock radiator. Based on our experimental data, the micro heat exchanger has about double the heat transfer of the stock radiator,” said Hurtado, a mechanical engineer. An IndyCar racing team is testing a similar design of the micro heat exchanger from Mezzo Technologies; the company’s president was Hurtado’s college advisor.
Knowledge transfer was a hot topic among the teams. Rutgers University’s racecar sported a custom-designed telemetry package. “We have actual data to back up design choices, ranging from things like choosing tires to selecting suspension geometry. In the last four years we haven’t had the same driver, so we can’t design the car around one driver. And that’s just one reason our telemetry is a useful development tool,” said Lawrence Sasso, the team member responsible for the 32-channel data-acquisition system that also uses The MathWorks’ MatLab software.
University of Wisconsin-Madison team leader Steven Faulkner said 2008 marked the first year the school’s racecar employed a “custom-designed steering wheel that integrates over a CAN network with the ECU and the onboard data-acquisition system. Last year the car’s steering wheel had buttons for brake bias control and shifting, but this year the steering wheel has buttons for launch control, traction control, automatic shifting, brake bias adjustments, and paddle shifting. Centralizing these controls on the steering wheel avoids adding complexity and weight to the wiring harness.”
While on-track vehicle performance data tracking was extremely relevant, so too was the off-track communication among team members. “We have an online centralized file repository," Faulkner said. "This computer-based system means flawless knowledge management. No one runs around in the dark. If someone makes a change to the racecar, that change gets updated to everyone immediately.” As a veteran of FSAE competitions, the University of Wisconsin-Madison team has fine-tuned its year-to-year racecar development process. “We’re big fans of an evolving design, not radical changes,” Faulkner said.
The most radical change at this year’s FSAE was a change of venue, moving from Ford’s proving ground in Romeo, MI, to the Michigan International Speedway. Albert Carter, team member with the University of Hawaii-Manoa, said being at a site where professional drivers compete was most unusual. “There’s not a racetrack in Hawaii, so this is totally different for us,” he said. As a rookie at FSAE 2008, Carter found that competing against other university teams was motivating. "I’m not intimidated," he said. "It’s a competitive spirit here, but there’s also a spirit of camaraderie.”