When assistant aerospace engineering professor Graham Doig first pitched the idea of designing a solar-powered vehicle that would shatter a world record, he was met with little enthusiasm.

Nobody on campus really grasped the idea at first, Doig said. But once he held a meeting with his students to explain, it clicked.

“Here we are a year later with dozens of students, a workshop, well over a quarter of a million dollars in funding, sponsorship, donations, etc.,” Doig said in an emailed statement. “And, hopefully, soon, a car and then a world record.”

What began as Doig’s seemingly far-fetched idea is now Cal Poly’s very own Prototype Vehicles Laboratory (PROVE Lab), a student-run group of dedicated engineers, designers and marketers ready to take the official record for the fastest solar-powered vehicle in existence.  

The Guinness World Record for the fastest is held at 56.75 miles per hour. PROVE Lab’s vehicle, utilizing only solar power without a battery, aims at hitting 65, possibly even 70.

“Nobody really believes this is possible,” co-project manager and mechanical engineering senior Will Sutton said. “But we’re pushing limits to put Cal Poly on the map.”

Solar powered

PROVE Lab electrical engineers face a particularly tough challenge: creating an electrical system that powers the vehicle solely using energy from the sun. There’s no other car like this in existence, so the team doesn’t have many examples to draw from.

“We tried to research how to build a [solar panel] array like this, but again, with no battery, a lot of this is new and innovative stuff that not many have done, so it’s pretty groundbreaking,” co-lead of the electrical engineering team and electrical engineering senior Joey Gross said.

The electrical engineers are using commercial-grade solar cells (the same kind you’d put on the roof of a house) to power a vehicle that’s set to break the speed limit on the freeway. The car will hit that speed using only two kilowatts of power. That’s about as much as it takes to turn on a hair dryer.

“Another big part we’re working on is balancing the array, making sure it’s operating at a voltage we want and a current we want,” Gross said.

Finding a way to properly build and balance such an array is only half the challenge. The solar cells are extremely fragile and expensive, which is why there’s an entirely separate team dedicated to producing a protective system for them.

Mechanical engineering senior Alex Power leads the team designing the suspension system. That system, he said, is what provides safety for the solar panels. Using a Computer Numerical Control (CNC) machine, Power cut into thick pieces of metal to make precisely the right shape and size parts for the suspension. The newly cut piece will allow the suspension to move up and down, thereby protecting the solar cells from the shock of an impact.

Safety first

While it’s critical for the solar panels to remain safe, there’s one thing even more important to keep protected: the driver. Peter Pratt, a mechanical engineer senior and lead of the structures team, is in charge of the system designed to do just that.

Pratt points out the parts of the vehicle that he and his team have been working on in a wooden model sitting outside of the PROVE Lab workshop. The chassis, or internal structure of the car, will be made of carbon fiber, he said. The carbon fiber composites are four times stronger than steel, but they’re light enough that two people will be able to lift the car.

“As the car drives it hits bumps, and so that’s what we’re designing for. No matter the force that this takes, we’re designing for a thousand times what we expect, so that way anything that we come across, the chassis and the car are strong enough to take it,” Pratt said. “We’re going to take steel plates, running it through the carbon fiber and welding the roll bars to that.”

Sharing the wealth

Undertaking such a massive project wouldn’t be possible without a little outside help. In the last year, the students of PROVE Lab have received financial and technical support from numerous organizations. Some resources come in the form of donations from private and corporate sponsors; others in the form of expertise from the top dogs of the industry, like Tesla and Google.

Cal Poly students aren’t the only ones benefitting from the generosity of PROVE Lab supporters. Come January, students in low-performing Central Coast school districts will have access to after-school STEM education programs, thanks to a $65,000 grant from the American Honda Foundation. Students from PROVE Lab’s outreach team will be leading eighth graders in building their own miniature prototype solar vehicles. Aerospace engineering senior Thomas Rohrbach is the lead for technical coordination within the outreach team and in charge of creating lesson plans for the program. 

“We’re hoping to put a lot of different components in front of them and have them come back to us and do what engineers do and justify their decisions,” Rohrbach said. “We’re not going to give them a kit. It’s gonna be, ‘Here’s three motor options. Tell me why you picked this one.’”

In it for the long haul

This project has been a long time coming. Doig first pitched the idea last year, and thus far, it looks like the car won’t be ready to break the world record until June. But until then, the team is working diligently toward making it happen — and keeping their achievements on record for future employers to take note of.

“Going into interviews for internships and whatnot, they’ll look over my resume, they skip over school, they skip over volunteer, they skip over everything and they’re like, ‘What are you doing for this club?’” Pratt said.

Doig also believes this will launch students into unprecedented places.

“The students are doing something that hardly any student anywhere gets the experience of— building a real, working vehicle that does something that no other vehicle in history has done before,” Doig said in his email. “So the students we have coming through PROVE now, we hope, are going to go on to do amazing things.”