The 109 open-wheel racecar originals competing at the 2014 Formula SAE Michigan event were created and built by collegiate students eager to show the results of their product-development decisions.
Teams from North America, Asia, and Europe picked their engine months before the May competition at the Michigan International Speedway in Brooklyn, MI. The popular choices were 600-cc four-cylinder engines (sport bike engines) and 450-cc single-cylinder engines (activity-vehicle engines) from Honda, Kawasaki, Suzuki, and Yamaha.
Internal engine modifications are uncommon, noted Luke Cruff, Manager of Design and Development at Mahle Powertrain LLC in Farmington Hills, MI, and a Formula SAE Michigan design judge. “Most of the engineering is spent on making the engine system compliant with the Formula SAE rules—in particular the air restrictor, which is used to control power output," he explained to SAE Magazines. "The introduction of the air restrictor causes the engine to need to be ‘de-tuned’ and re-optimized for a lower peak power speed."
There are usually several unique solutions for the vehicle’s final drive and powertrain mounting configurations, Cruff continued. "Many times these designs are much more important to the performance and driveability of the vehicle than base engine modifications would be, which is another reason most teams choose to leave the base engines stock and optimize the vehicle in other areas.”
A team’s product-development decisions are track-tested via performance-based measurements.
Formula SAE’s dynamic evaluations feature an endurance test covering 22 km (13.7 mi); an acceleration test covering 75 m (246 ft); a cornering test on a flat skid pad with constant-radius turns; and an autocross event combining the aspects of acceleration, braking, and cornering.
Team leader Vincent Sorrento and his Virginia Tech teammates were hyped for the 36th annual Formula SAE Michigan challenges as they exited one of the speedway's garages that was set up to cars with and without a driver.
Like all teams, Virginia Tech’s racecar would go through a full vehicle technical inspection. There would be cost, presentation, and other static judging events as well as the highly anticipated motoring events.
“We have to make sure that the driver is, number one, safe and that the driver has good vision capability,” Sorrento, a VT junior studying mechanical engineering, told SAE Magazines.
In developing their 2014 racecar, the VT team used a Human Solutions’ Ramsis software package to look at ergonomic considerations. “Over the summer in 2013 we had our drivers scanned, so their anthropometry could be viewed in CAD. We analyzed many things,” Sorrrento said. The human-machine interface checklist entailed things like determining if a driver’s elbows would hit the chassis while steering, as well as whether the seat would fit properly so that the driver’s posture wouldn’t cause fatigue over time.
The ergonomics review also addressed the driver’s sight lines. “We mapped out where the wings and tires should be, so the driver will be able to see beyond the height of the cones,” said Sorrento, adding, “The driver can drive much faster if he can clearly see the path of cones on the skid pad.”
The Virginia Tech team would go on to win the Presentation event (one of three static events) at FSAE 2014. It placed 34th overall.
When Ohio State University hopped on the fast track for their 2014 Formula SAE product-development process, weight reduction considerations influenced what alterations would be made. By opting for smaller wheels and designing a next-generation, two-piece carbon-fiber monocoque chassis, more than 60 lb (27 kg) was shaved from the previous year’s car.
Explained team captain Evan Bunner: “Changing from 13-in to 10-in wheels allowed us to downsize the components inside the wheels, including the brake parts, suspension uprights, and suspension arms. It also gave us the opportunity to make our own wheels out of carbon fiber.” Each three-piece wheel weighed 2.5 lb (1.1 kg) versus each single-piece 5.2-lb (2.4-kg) 13-in forged aluminum wheel used on the 2013 car.
For the first time since the early 1990s, OSU’s Formula SAE racecar sported an aero package. The three-element front wing and the two-element rear wing were fully adjustable. “You can set it for acceleration, low-drag, or high-downforce situations. Thanks to Chrysler sponsorship, we did wind-tunnel testing at their Auburn Hills, MI, facility. We analyzed drag, downforce, and rotated the car to measure aerodynamic effects in yaw,” said Bunner, a senior studying urban design.
The OSU racecar was also road-tested with and without an aero package. “Our testing showed faster lap times with an aero package,” said Bunner.
The university finished 24th overall at FSAE 2014.
Michael Jasper, chief engineer for Georgia Institute of Technology’s Formula SAE entry, said aero-wings were considered for the team’s 2014 racecar. “A prototype set was mounted to the car, and we did a limited amount of testing with it. But the car needed to be better-suited for an aero package,” Jasper said, “The wings brought about certain factors that we didn’t consider, like mounting points. With aero, you’ve got to design it with the car from the ground up if it’s going to be an effective part of it.”
Georgia Tech’s team focused their efforts on making the subsystems more robust and reliable. “We had a lot of electrical issues last year, so we went through the entire car and said, ‘How can we weather-pack our electrical system? How can we strain-relieve it? And how can we make it easier to troubleshoot?’ We previously ran a turbocharged single-cylinder engine, but the turbo has demands for cooling and oiling. This year we went with a four-cylinder gasoline Honda CBR600 that’s a proven design,” said Jasper, a 2014 mechanical engineering Georgia Tech graduate.
Georgia Tech placed 25th at FSAE 2014.
The overall winner of the 2014 FSAE Michigan event was Oregon State University (U.S.), folowed, in order, by Technical University of Munich (Germany), Universitat Stuttgart (Germany), FH-Joanneum Graz (Austria), University of Akron (U.S.), Université Laval (Canada), Auburn University (U.S.), University of Michigan-Ann Arbor (U.S.), University of Florida (U.S.), and Centro Universitario Da FEI (Brazil).Continue reading »