Building A Rubber Band-Powered Race for the Ages

By Core77 on September 1, 2015 in Design - Other
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Ready, set—snap! Earlier this month, Art Center College of Design hosted their annual Formula E competition (the ‘E’ is for elastic) where students, professionals—and anyone else crazy enough to participate—are invited to build and race rubber-band-powered toy cars. The main competition takes place on the art school’s Pasadena campus, but has quickly spread to Beijing as teams from around the globe come together to showcase and test lightweight vehicles crafted from anything participants can get their hands on with materials ranging from titanium and carbon fiber to masonite and plywood.

The race got its start back in the 1980’s when one of the industrial design teachers felt that his students should go through the rigorous process of making something functional—as opposed to building the foam and styrene models collecting dust. Looking to MIT professor Woodie Flowers for inspiration, the teacher devised a project where each student had to build a vehicle that could make it around the school—powered solely by a 16-foot rubber band. “I did not have the experience of being a student in the class, but I knew many people who had,” says Andy Ogden, Chair of Art Center’s Graduate Industrial Design Department. “They would constantly talk about his project, how much they learned and how fond of it they were. So, in 2005, when I became the chair of the program, I realized we needed to have some kind of project that really gave the students a chance to build something that had to work. We updated the rules of the game, came up with the idea for the current competition and we’ve been doing it ever since.”

Ogden has seen a lot of changes over the past ten years as participants improve upon the innovations of preceding challengers. “Five years ago, the best cars were three wheel designs,” Ogden recalls. “They were incredibly lightweight with skinny little tires, like a bicycle. This year, we’re really seeing that they’re turning into cars in a more realistic sense. They have four wheels and, instead of a brake, they’re using a clutch. Instead of taking the sixteen feet of rubber band and making a twelve inch loop, they’re turning it into a bundle that’s about half that.” Bundling the rubber band is an integral part of building a vehicle, as the shorter the loop is, the more torque it has. “They’re getting an incredible amount of power out of the rubber band, but what they have to do is control how many rotations because they can’t complete the course if it unwinds during the race,” Ogden says. Inventiveness plays a large role in how the rubber band is held when wound up and then released. Sudden surges of power from uncontrolled releases have led to many cars meeting their destruction on the course, a consequence of lack of control.

The 16-foot rubber band is still an essential part of the race, but an updated list of official rules and constraints further dictates what participants can and cannot do. “Of course, designers are really creative, so the first thing they want to try is tying the rubber band to a stake in one place and then transporting the vehicle back like a big sling shot—and the answer is no,” Ogden says. “You can’t have anything attached to the vehicle outside and the rubber band has to power it.” The official mandated rubber band dimensions are a 3/16-inch by 16-foot rubber strip, produced by FAI Tan Rubber or PeckPolymers. Vehicles must achieve forward motion solely by the energy stored within that rubber band, which can only be attached to one vehicle. Each vehicle must also be able to hold itself at the starting line, requiring some type of brake or clutch to control the car. “So those are the kinds of things that people typically will invent, and those you need to progress,” Ogden says.

Teams have between 2 to 4 members, with one student being from a local city college to encourage more interdisciplinary collaboration beyond the school’s borders. “Very often, those members end up being very important with the skills and intellectual talent they bring to the table,” Ogden says. The most notable of all the rules specifically geared towards the race’s designer constituency is 1.4 which reads: “The contest for measuring aesthetic and build quality achievement should precede all other (dynamic) contests.”

“The rules don’t really change much and that’s an important thing because what we want to do is create something that really simulates the real marketplace,” he says. “That’s the way it is out there. What becomes really important is for the students to learn from all the previous examples that are available to study. Then it largely becomes an issue about being able to find new materials, new components, think about the problem in a different way, just a little bit better.” Sourcing materials adds another real-world element to the competition, as participants who research and find access to better components have an advantage, similar to the real product marketplace.

The main race takes place at Art Center’s Pasadena campus, wending its way through their Sculpture Garden for various courses such as the Sinclair Hill Climb, Ashtray Alley Drag, Sculpture Garden Flats and the Figure 8. “The main competitions take place simply on the sidewalks we have outside of the building at the college,” Ogden says. “We just started racing on them and they have now become solidified as the official dimensions.” When a few Chinese design and technology schools wanted a piece of the fun, however, they built their own track in Beijing to compete, modeling it after Art Center’s garden sidewalks.

This year, Team Leadfinger, made up of two Art Center ID graduate students, Zach Schlossberg and Zach Buchman, and Pasadena City College student Atria Azarmi, took the gold, winning five races and securing ‘Best of Show’ for their design. The winning vehicle held its rubber band longitudinally and featured a titanium front axle, giving it extra resilience and strength, as well as a carbon fiber tube making up the main body of the car. Parts were connected by rapid-prototyped pieces reinforced with carbon fiber. “A lot of the students quickly learn the difference between rapid-prototyped components, which are so easy to make and very gratifying to design, but are basically Happy Meal toys,” Ogden says. “They’re models. They’re not really meant to be put into use as structural pieces.” Carbon fiber rods are used to add additional reinforcements or are printed in ways so that the grain increases their strength. Team Leadfinger scavenged eBay to track down a carbon fiber disc brake from a discontinued radio-controlled car to work as a clutch and control the power, while a modified toy helicopter tail rotor was used for the gear train drive. Various wheels and tires were taken and tested from other toys and models until a perfect weight and balance was achieved.

Most of us drive around in cars and have no idea what makes them work,” Ogden says. “So this is a really steep learning curve. Throw everybody into the ocean and get them to swim to understand the geometry and the dynamics of how a very simple car works.” One of the key learnings necessary to making a successful car is a differential, a gear mechanism that allows wheels to rotate at different speeds—what gives cars the ability to turn while still maintaining traction. Team Leadfinger invented their own for the race, using a very small one-blade bearing carefully placed inside modified hubs of a radio-controlled wheel. Geared nylon components from a toy helicopter were removed from their shafts and carefully attached. By doing this, the winning team was able to make a wheel that could stay on the axle and, at the same time, have a very lightweight limited-slip differential (LSD)—critical for a four wheel car. “Some of this stuff is very delicate circuitry and you have to break a number of parts to make it work,” Ogden says. “They would take components off [other vehicles] and attach it to their own axle to find a way to pin it to the axle and they would make their own bearing so they could assemble their own transmission and differential.”

“Part of what [Formula E] does is it creates this wonderful example for us to have a dialogue about how products go through these different phases,” Ogden says. “At one point, it’s all about a strategy or the overall big idea and then it reaches the phase where it’s all going up. In the end, you are on stage so it has to work and if it doesn’t, your sense of self and the relative success of your work is out there for everybody to see. We end up having lots of dialogue about how that translates into other kinds of products.” Those interested in competing or partnering next year can find out more about the Formula E race here.

Images by Richshell A. Allen and Frank Yuan. Courtesy of Art Center.