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Shifting Gears

How a dedicated team of students built a world-class race car against all odds.

M37-Shifting-Gears-Opener

Each year, dozens of collegiate teams flock to the New Hampshire Motor Speedway to compete in the International SAE Formula Hybrid Competition, a grueling four-day event where students race formula-style gas/electric hybrid race cars that they’ve designed and built.

REWIND: It’s April 29, 2011, two days before the competition. The Yale University team, Bulldogs Racing (BDR), is at an off-campus site testing their race car one last time. Tears of joy stream as thousands of man-hours from a small but dedicated team of about a dozen students is finally realized — the beast is in motion and it’s looking good! Minutes later those tears shift from joy to despair. In the most improbable of scenarios, a single bolt had come loose, jamming the engine, and tearing the transmission to shreds. With not enough time left to source a new transmission, a year’s worth of work is gone. Game over. Sorry, Yale.

Unfortunately, the 2012 season wasn’t much better for the Bulldogs. Long story short, they didn’t even come close to making it to competition. The team was a little light, and in a way it’s understandable. Not only did Yale have a poor history of even getting a car to the competition, they never did very well when they did make it there. Getting students to trade every Thursday, Friday, and Saturday night of their college experience for something that has a strong likelihood of failure is a pretty tough sell. Imagine the recruiting poster: “Compromise your grades, miss out on social opportunities, sleep less than you ever thought was possible! Join Bulldogs Racing!”

Using old fashioned boat-building techniques and laser-cut plywood cross sections, Alex Carrillo creates the plug for the race car body

Using old fashioned boat-building techniques and laser-cut plywood cross sections, Alex Carrillo creates the plug for the race car body

PAUSE: So why do they do it? Because it’s not about winning, or even the race for that matter — it’s about the experience. Ivy-league prep assumptions aside, many Yale students would rather don safety glasses than a bow tie. They may not know anything about suspension geometry, laying carbon fiber, or tuning an engine when they sign on, but they join to learn.

For most students, it’s both empowering and humbling. Empowering, in learning how to transform hunks of metal and plastic into functional parts. Humbling, in that the former is much more difficult than it sounds. Mostly though, it’s about being part of something bigger than themselves. In 10 years, most students probably won’t remember their linear algebra course, but they’ll never forget the feel of brake fluid on their hands, the sweet smell of an angle grinder ripping through steel, and more than anything, the late night camaraderie and laughs.

It goes without saying that building a race car is a pretty lofty endeavor, especially for students who have likely spent more hours playing video games than turning a wrench. A race car is thousands of carefully designed, machined, and welded parts, all working in unison to tear around some type of course without falling apart. Here, we’re talking about a hybrid vehicle, so now add to the mix a complex electrical system consisting of high-power circuits to drive a motor and low-power circuits to control everything else.

The Formula Hybrid Competition consists of three dynamic events: an acceleration run, an autocross event, and an endurance race. Each team is limited in the amount of “energy” they can carry, and they’re free to distribute it between gasoline and batteries as they see fit to maximize their performance in the three events.

Joe Belter and Chinmay Jaju CNC-machine the uprights.

Joe Belter and Chinmay Jaju CNC-machine the uprights.

FAST-FORWARD: In September 2012, two sophomores, Alex Villarreal and Chinmay Jaju, decide to turn BDR around. Neither had much experience, but they weren’t short on gumption. With a few thousand bucks and a poorly outfitted garage (which incidentally doubled as a loading dock), they set out to revamp BDR. The first stop was a new faculty advisor to mentor the team and supervise the build. Dr. Joseph Zinter, assistant director of the Yale Center for Engineering Innovation and Design (CEID), was the logical choice: a serial maker and gear head who feels more comfortable in welding leathers than a tweed coat. Zinter agrees under one simple rule: “If we do this, we go all in.”

Months of designing, calculating, planning, and sourcing parts were followed by long hours in the garage and machine shop transforming piles of raw materials into a chassis, drivetrain, steering system, suspension, electrical system, body, and finally, a race car. It was one hell of a year — each student pushed further than they’d ever been, with many unforgettable stories, travesties, and successes along the way, but the best part of this story comes from what happened at the race.

Belter and Jaju test-fit the uprights on the welded chassis.

Belter and Jaju test-fit the uprights on the welded chassis.

PLAY: On the morning of the 2013 competition, BDR rolls into the New Hampshire Motor Speedway, passing dozens of professional-looking race-car trailers from schools across the country. They park and assemble to lift their race car from the back of a rented U-Haul truck. Yale already didn’t have a great reputation at this race, and the U-Haul didn’t help, so a few snide remarks were expected (and received). It was all good, though, and the team is just happy to be there — even days before the race, they weren’t sure they would make it.

The first, and sometimes the most challenging, part of the competition is inspection, where professionals spend hours going through each car to make sure the vehicle is safe and mechanically and electrically sound. Each team is given a list of things to change and fix, then it’s off to the pits for frantic repairs and modifications. Here, every minute counts. If a car doesn’t pass inspection in time for an event, it isn’t allowed to compete. About a quarter of the teams never pass inspection and are relegated to watch the other schools race from the sidelines.

The plug gets a final release coat before being used to make the fiberglass molds, which are then used to create the carbon fiber body.

The plug gets a final release coat before being used to make the fiberglass molds, which are then used to create the carbon fiber body.

Despite minor modifications, the BDR car is the first to pass inspection, and the other schools start to give Yale a second look. The Yale team is one part stoked and one part haunted by their history, assuming something will inevitably go wrong. They prep for the first event, the acceleration run, just hours away. The car is ready, every bolt double-checked, and it exudes confidence, but the team seems far less poised.

Then, the chaotic pits come to a screeching halt when it’s announced that the autocross course is open for a walkthrough. Autocross would be the second event of the day, and crew members from all schools run over to see what they’ll soon face.

The bare bones BDR race car on day one of testing.

The bare bones BDR race car on day one of testing.

Yale had done their homework, studied the previous years’ courses, and designed their gearing accordingly. Historically, the autocross course was tight, favoring quick acceleration and high torque, but you could have driven a dump truck through this layout. It was wide open and much more designed to favor high speeds. In talking with other teams, the Yale race car had one of the lowest top speeds around.

The competition requires teams to maintain the same gearing for all events, so the Yale team quickly recognizes they’re in serious trouble, since autocross accounts for twice as many points as the acceleration run. After a quick team huddle, they decide to change their gearing, but at this point, they only have about 45 minutes to do it. The adrenaline is seriously pumping, and a year’s worth of work in on the line.

“It was like a NASCAR pit stop without the tools you need,” said Alex Carrillo, a freshman who wore two important hats on the team: control systems lead and comic relief. In an absolute fury they jack up the car, and remove the body and the sprockets on the engine and motor. They are organized, ready, and on track to make it to the line in time. They shorten the chains and loop them around the newly installed sprockets.

The Bulldogs Racing Team performs some final tuning on the car.

The Bulldogs Racing Team performs some final tuning on the car.

“We have a problem,” says Joe Belter, a graduate student in mechanical engineering and the resident mechanical guru. It only takes seconds for the gravity to set in. The new sprocket configuration is such that they can’t get both the motor and engine chains to be safely tensioned. “Half link,” barks Zinter. “We don’t have one — they don’t exist for this size chain,” says another team member. “I know, make a half link,” says Zinter. In true MacGyver fashion, with only a vice and angle grinder, sparks fly. In less than five minutes, greasy, shaking hands create and install the fix. After a quick reinspection, the team dashes the car to the starting line of the acceleration event, with only seconds to spare before disqualification.

Fingers are crossed, and the team is praying the car makes it down the track in one piece. Belter is behind the wheel. He rolls to the line, gets the thumbs up, and roars down the straightaway. The crowd is cheering, and all eyes shift from the car to the clock. The collective jaw of BDR drops as they hear the announcer: “At 5.283 seconds, Yale resets fast time for the day.” The unlikely Yale would end up winning the acceleration run.

The elation was short-lived, as the autocross event was just around the corner. After having calmed the butterflies, a quiet confidence is starting to set in on the BDR team, the type you would expect from a well-oiled machine that has been running nonstop for a year.

On the final day of testing, things are looking solid for the BDR team.

On the final day of testing, things are looking solid for the BDR team.

They roll the car to the line. Adam Goone, a senior in mechanical engineering, is behind the wheel. Goone is one of two seniors who had stuck with BDR for the entirety of his college career, and the day he’d dreamed of is finally here. Despite having been through a physical and emotional roller coaster in those four years, he’s as cool as ice, a born driver.

He gives the crowd and thousands of people watching online quite the show when the rear end slips out from behind him around a tight turn. He loses it and is headed for the grass. Hearts stop, but after an amazing recovery, he continues to tear up the track, and ultimately claims victory in the autocross event.

Yale would end up winning the endurance event as well, sweeping the competition and coming in first place overall: International SAE Formula Hybrid Competition champions. Oh, and the custom half link held up just fine.

It was a motley crew if ever there was one. Quite a few team members didn’t know the difference between a nut and a bolt when they started, the engine tech and welder was an anthropology major, and the chief engineer didn’t have a driver’s license. When you think Yale, you probably don’t think engineering or making, but this small team on a shoestring budget (while dodging deliveries on a loading dock) was able to build a world-class car. It just took a little gumption, a few sacrifices along the way, and a strong desire to make. 

Alex Carrillo

Alejandro (Alex) Carrillo is an electrical engineering major at Yale University, and hails from Brooklyn, N.Y. In his spare time he builds robots, explores NYC history, and teaches people how to do the same.


Joseph Zinter

Dr. Joseph Zinter is the assistant director at the Yale Center for Engineering Innovation and Design (CEID), a lecturer in the Department of Mechanical Engineering and Materials Science, and the proud faculty advisor for the Bulldogs Racing Team.


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