Old wooden catapult against grey sky background
Do you know what a trebuchet is?
It’s an hour before dawn on a late November Thursday as I write this. It’s dark outside, and freezing, which is a pity because my son, Charles, and I need to be out there in a few minutes. This being rural Louisiana, you might think that the only thing that would get a couple of dudes out of bed before dawn would be a duck hunting trip or something, but this morning we’ll be going no further than the carport, where awaits the partially-completed mother of all school construction projects—a trebuchet.
If you don’t know what a trebuchet is, lucky you. I didn’t either until this time last week, when Charles offhandedly mentioned that he was supposed to build one for his senior physics class. A trebuchet is one of those catapults that were all the rage with medieval warlords before gunpowder was invented, used to hurl heavy stones (and other, nastier things) at other people’s castles. Accurately known as a “counterweight trebuchet,” the contraption consists of a long arm that rotates around an axle mounted high on a pyramid-shaped frame. From the short end of this arm are suspended heavy weights, while the longer (i.e. “the “business”) end holds a sling into which you load your projectile of choice. When the weighted short end is raised then released, the long arm whips around with wicked speed, launching your rock, boiling oil, hapless serf or what-have-you toward your enemy’s defenses with considerable velocity. You can see why this project would appeal to physics nerds.
To achieve full marks, class members needed to build a trebuchet capable of launching a ten-pound pumpkin sixty feet or more—a feat that, according to Charles’s impenetrable physics calculations, meant his catapult would need at least an eight-foot-long throwing arm, and ninety pounds of counterweight.
I’ve had to take his word for it. Being more of an English lit nerd, math and I have never really gotten along. But I do like building things. So last weekend, when sounds of muffled banging from the barn suggested that Charles had gotten started on his trebuchet, I went to investigate. We have more or less been at it ever since. Of course there’s a limit to how much any parent should help a child with his homework, but trust me: as an unreconstructed English major with a math allergy that dates from early middle school, my ability to positively affect the outcome of this project has been limited to providing carpentry advice and ensuring that Charles doesn’t lose a thumb to the mitre saw. In fact, he should probably get extra points for having let his dad help, since my participation probably counts as more of a handicap than anything else.
Anyway, here we are, day of the project’a deadline, with what we believe to be a fully operational counterweight trebuchet in our carport. It’s a squat, Monty Python-esque-looking contraption that, according to Charles’s physics calculations, should be capable of hurling fall vegetables into low earth orbit. But so far the only thing we’ve managed to throw sixty feet is a tennis shoe, which is now on the roof. Due to some error with the release angle, anything heavier tends to get blasted into the ground ten feet in front of the trebuchet. So, this morning we need to try and resolve this by fiddling with the sling release mechanism, then get the trebuchet loaded onto the truck in time for school. Will it work? I have no idea, but it’s been a fun project that makes me wish I hadn’t given up on math so soon. Better still is the chance it has provided to spend time with my youngest child, poised as he is on the launchpad for his own journey to college and beyond. This Christmas—Charles’s last at home, that’s the best gift of all.
To infinity, and beyond.
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