Not in my Job Description: A Real Fling
By Traci Vogel
It's not every day that a medieval war machine turns up on a college campus, but one sunny Sunday in June, a trebuchet appeared on one of Kenyon's fields.
A trebuchet is a siege engine that uses a swing arm with a sling to hurl objects into enemy territory. Built of timber, the machines proved key to military campaigns for centuries, from the siege of Acre in 1191 to that of Tenochtitlán in 1521.
Kenyon was not under siege by time-traveling marauders, but by a group of enthusiastic students aided by two of their professors. It all came about when Josh Omandam '10 was chatting at a holiday party with history professor Jeff Bowman, with whom he'd taken a course on the later Middle Ages, and physics professor Paula C. Turner, and mentioned his desire to build a trebuchet. Bowman says he doesn't usually make things with his students, but the three began to imagine collaborating on a hands-on extracurricular project.
Bowman enlisted the help of three other history majors—Alexander Boivin '09, Jon Lawrence '09, and Geoffrey Toy '10—one of whom, Jon, had dreamed of building a trebuchet since he was twelve years old. The students came up with schematics for a falling bucket counterweight, a type of trebuchet that uses gravity to pull the arm up and fling the sling forward.
"From the historic end of it, I didn't care what type they chose or what sorts of technology, as long as they understood something about the way what they made related to a historical context," says Bowman. Turner imposed a size limitation, dictated by the dimensions of the freight elevator to the workshop.
The group worked in off hours throughout spring semester, wrestling the piece of history to life. The throwing arm, the largest part of the trebuchet, was a ten-foot piece of lumber, and the base was about seven feet wide. After construction, Turner and the students wheeled the trebuchet to a test site, where they shot off dozens of tennis balls to determine the optimal length of the sling—"It turns out sling length is very important" to the trajectory, Turner says—and, at last, the engine was ready to be unveiled to the public.
That day a smattering of other students milled around, mostly Sunday afternoon passersby, says Bowman, "and suddenly there was a siege engine on the football field." Bowman was given first-firing honors. The students had been using double-sized tennis balls as ammunition, but that afternoon they also experimented with cabbage wrapped in duct tape—to simulate a severed head, sometimes used as a scare tactic in medieval times, Bowman explains. The longest launch traveled fifty-five yards. "It was my first experience with any siege engine, almost any weapon," Bowman says, still sounding a little giddy. "I haven't even been in a duck blind in almost twenty years. It was great."
While building a medieval siege engine was unlike any history project Bowman had been involved in, Turner says that "every five years or so" her physics students tend to conjure up a similarly extreme project, including a liquid nitrogen cannon and a tennis-ball launcher. Combining the disciplines of physics and history showed how "rich collaboration could be," says Bowman.
Something else the professors learned? "You know, these kids would have been okay Crusaders," jokes Bowman, with a laugh.