WENATCHEE — The Wenatchee Valley College campus contains no castles to defend nor barbarian hoards to quell.

But its central courtyard filled with downsized ancient artillery Friday, as the college’s physics students put their 11 homemade catapults to the test.

“Holy! He almost took it off!” a spectator exclaimed, as a tennis ball hurled by Eli Chambers’ machine thudded solidly against the top of its target — a structure in the shape of a castle turret built for the competition. Chambers, 18, captured the top prize for distance and accuracy.

He and his lab partner, Cory Mason, 26, built their tension-driven “onager-style” catapult with scrap lumber, dowel pins and taut manila rope.

Its “throwing arm” resembled a giant wooden cooking spoon that Mason carved by hand — and had the blister to prove it, Chambers said.

“This is all wood, no glue,” he said, explaining that he wanted to use as many of the same materials that ancient warriors would have had on hand.

Competitors had eight weeks to complete their catapults as part of a mandatory class project to use the principles of physics in action.

Bruce Unger, WVC physics professor, said the project also requires students to write a bibliography of their research and a paper using physics terms to explain how their catapult worked.

Friday’s contest was more for fun than grades. It has become a 10-year, almost-annual tradition at the college.

“They don’t have to win the contest to get a good grade on the project,” Unger said.

Some built trebuchet catapults, which use a counterweight system to launch the ball. Others used the ballista style — a crossbow-like system.

Cyrus and Niles Desmarais, 17-year-old twins from Chelan, chose the ballista type and watched as their small machine launched the ball nearly 30 feet.

“We liked the look of it,” Niles explained of their style choice.

His brother added, “We thought the bow would be very bendy and give a lot of tension.”

Not all launches flew as expected.

“Round it off to the nearest non-negative integer,” Unger called from the field, prepared to measure the distance, after one machine launched a ball backward.

Its builders craned their necks, momentarily baffled — and chagrined — by laughter and whoops from a crowd of about 60 spectators.

“Anybody up for a bonfire later?” competitor Thomas Brouwers, 27, called to the crowd, after the launch of his own machine fizzled. “I’ve got the starting wood!”

Christine Pratt: 665-1173

pratt@wenatcheeworld.com