Team led by freshman engineer build, launch trebuchet
Jonathan Topliff, a freshman in materials engineering, jumped into his ASU experience with both feet. During his first semester, he earned the title Lead Designer and Master Builder as part of the engineering student council team who built a 15-foot trebuchet with an 8-foot throwing arm.
Topliff gravitated to engineering citing the versatility and applied skill set. “You can do just about anything as an engineer,” he says.
He had always like building things, from LEGOs and Tinker Toys to more complex projects as he got older. He actually built his first trebuchet in the 7th grade. So when he heard that the engineering student council was considering building a trebuchet for homecoming, he signed on to help.
Topliff took the initiative to sketch out specifications and measurements. Plans in hand, he got the club’s VP of finance, Philip Burbank, and president, Jane Lacson, excited about the project and together they worked with student engagement coordinator, Katrina Vance, to secure funding.
Joined by a few other students the group set up shop on the south side of Engineering Center G (ECG). From the initial trip to Home Depot to the launch party, they spent nearly 70 hours building the trebuchet, who would come to be known as Sheila.
A trebuchet is made of three main parts: the base, throwing arm and counterweight basket. The group’s main concern was stress analysis on the different parts.
While Topliff’s original specifications turned out to be quite accurate overall, he did run into design challenges. The basket, made from old jeans, metal grommets and leather, was too heavy. Undaunted, he solved the problem by using basketball nets held together with zip-ties.
For their first test, the group made a projectile out of the tarps used to secure Sheila at night (to protect her from any UA students). The goal was to ensure safety, proper clearance for the arm to move, and to see if it worked. The test launch went 100 feet.
At her official launch party, Sheila drew a crowd of students eager to see pumpkins hurled into the air, and have the opportunity to compete in the how-far-will-it-go contest. The team launched at least a dozen pumpkins, adding more weight to the counterweight basket each time. The final launch, with over 400 pounds of weight in the basket, went 212 feet.
Today, Sheila rests outside the Engineering Student Center.
Why a trebuchet? It comes back to building things, Topliff says. “Some people play tennis, some shop. I like to build large objects that launch things.”
He also says that the group project was a great learning experience. “I learned to always think ahead, the importance of clear communication among team members and to take accountability for my part in making it a successful project,” he says.
Topliff has stayed involved with the student council and is now the interclub communications chair.
Next on the horizon? Topliff says possibly a generation 2 trebuchet with a floating arm to give it more force.
