Formula Racing: Lighter, Sleeker, Faster
For the Dartmouth Formula Racing team, the most striking difference between its 2004 and 2003 cars was weight.
The team built a car this year that weighed in at 489 pounds — nearly 100 pounds less than last year’s and the first-ever sub-500-pound car in the eight years that the team has been competing. The drive to shed extra weight affected nearly every element of the design, leading to a smaller, sleeker, faster car, team members said. “It couldn’t just be functional,” says co-captain Scott Lish ’03, Th’04. “It had to be light, and it had to be somewhat revolutionized across the board if we were going to do well, because the other teams at the competition were getting better.” That mindset paid off when the team’s car finished eighth out of 140 entered vehicles at the annual Formula SAE (Society of Automotive Engineers) competition for college students in May. The ranking was an improvement over last year, when the team placed 18th, and just shy of this year’s goal of finishing in the top five.
But their second-ever top-10 ranking was only one of the team’s accomplishments. For the first time Dartmouth was among some 20 teams selected for the semi-finals of the design event, in which judges grill students for five hours on all aspects of the car’s design and manufacture. In addition, the DFR car was the first one to pass a technical inspection required before it could be driven in competition. And the car’s design was a finalist in a separate competition sponsored by Parametric Technologies Co., which makes the software that the team used to help design this year’s car.
“This is one of the largest and best organized teams we’ve had, and they’ve taken on the most ambitious project that any of our teams ever have,” says Douglas Fraser, a Thayer School research engineer who has advised DFR since its inception. “They really impress me. It was very professionally run.”
This year’s achievements are especially impressive given that the five-day Formula SAE competition, which takes place in the parking lot of the Silverdome in Pontiac, Michigan, attracts teams from around the world. Unlike Dartmouth, many schools represented at the event have programs in automative engineering and faculty whose sole job is to advise the racing team. In Michigan the team competed in seven events both on and off the track. The four driving events tested the car’s acceleration, braking and cornering ability, performance, fuel economy, and reliability; the three non-driving events evaluated the car’s design, cost, marketability, and the team’s presentation skills.
To create this year’s DFR car, some 30 undergraduate and graduate students put in thousands of hours. The 11-month process began almost as soon as last year’s competition had ended and involved continually redesigning components in a quest to come up with an overall design that balanced sometimes conflicting design goals: lightness, speed, reliability and driver comfort. “Right from the get-go, we were committed to change in leaps and bounds, and by doing that, ensured that pretty much nothing on the car would be the same,” says team captain Ariel Diaz ’02, Th’04. For instance, last year the team bought an aluminum seat from a third-party racing company. This year, the team decided it could do better by making its own fiberglass seat using the aluminum one as a mold. The new seat wasn’t stiff or supportive enough, however, so the team tried making one out of carbon fiber instead. The team finally realized it could incorporate the seat into the required “driver close-out,” a barrier between the driver and the road that prevents stones and other debris from flying into the vehicle. “It ended up being lighter than we could ever have imagined and better integrated with the car itself,” Diaz says.
By having one part serve two functions, the team saved 8 1/2 pounds — not an insignificant amount given that even tiny weight reductions can have a big overall impact.
The team also worked to improve the aesthetics of the car. In addition to giving the car a leaner look by trimming inches from its height, length and width, the team used polyester-based aircraft fabric, which conformed to the angular shape of the frame, rather than rounded fiberglass body panels. “We wanted to get a stealthy look to the car — show off the angles,” says team co-captain Dave Blindheim ’03, Th’04.
Downsizing the frame wasn’t merely about appearances: The frame weighed 67 pounds, more than 10 pounds less than last year. And a smaller frame meant that other parts could be lighter as well.
Another goal was to create a car that could be driven by different-sized team members. “There’s an emphasis that the team places on allowing everyone to be able to drive,” says Emilie Fetscher ’03, Th’04, who worked on driver controls. “It’s kind of the team’s philosophy.” The pedal package — clutch, brake and throttle pedal — is more easily adjustable than last year’s, sliding along the car’s frame and locking into place with pins, Fetscher says. The new system allows a single person to adjust the pedals in less than 15 seconds, while last year’s required two people and took nearly a minute.
Team members got some help designing the car from engineering software programs Pro/ENGINEER and Pro/MECHANICA. Although last year students used the programs to analyze individual parts, this year the team used the software to get a preview of how different parts would work together and how they would fit into the car, Lish said.
The team did run into a few snags at the competition. The car had fuel-delivery problems that resulted in reduced power during the 22-lap endurance event, which makes up the biggest portion of a team’s total score. In addition, the rear wheels started coming loose because of worn-down aluminum hubs that were splined onto steel shafts. But the DFR team finished the race, beating the odds in an event in which roughly two-thirds of the teams are compelled to drop out because of such problems as spilled fluids, engine fires, and electrical failures.
Brian Mason ’03, Th’04, the fundraising and public relations chair, said the team strives to include anyone who’s interested, and above all, to have fun. “It’s one of the best real-world engineering experience that Thayer School has to offer,” he says.comments powered by Disqus