Treb Terror
The counterpoise trebuchet has seen military service for centuries.
Public domain.
I bought my first putt-putt BB gun at age seven. I went hunting not because I liked deer meat but because I just enjoyed walking through the woods carrying a gun with my dad. I bought my first AR-15 in the 10th grade, and my favorite spud gun will pass for a 57mm recoilless rifle in dim light. Once I took physics in high school, all I wanted to do was calculate how cannonballs behaved when fired. I’ve got the gun nerd gene.
My best friend Jason and I once got on a wicked trebuchet kick. A trebuchet is a subset of the catapult. A traditional catapult is a brute force machine wherein the power of a spring, in this case a flexible shaft, is used to throw stuff. By contrast, the trebuchet is so much more elegant.
A counterpoise trebuchet is an amazingly elegant machine.
Public domain.
Technical Stuff
The counterpoise trebuchet was first used in the 12th century. This was a sort of medieval siege engine that used power stored up in a counterweight to fling a projectile. While the archetypal treb ammo was typically rough-hewn stone balls, they could also throw incendiary payloads and ghastly stuff like dead, diseased animals.
A counterpoise trebuchet is basically a big lever mounted on a frame. The shorter end supports the counterweight. The longer arm sports a rope sling on the end that is timed to deploy at just the right moment to maximize mechanical advantage.
Traditional trebuchets were most commonly constructed outside of a fortified town. In fact, once erected, the azimuth of fire was fixed. Adjusting the sling length, counterweight, mass of the projectile, and geometry of the release hook could fine-tune the range.
Ancient sieges were most typically tedious, drawn-out affairs. The attacking army would encamp around a castle or city and then build the siege engines as necessary. The machines were then dismantled or burned once the operation was complete.
Jason and I built several of these machines. The smallest sits on a desktop and throws BBs across the room. One of them is about the size of a toaster oven and chucks marbles. The waist-high version uses bricks for a counterweight and will throw a baseball about a hundred feet. It is shockingly accurate. You can catch a baseball, keep your gloved hand in exactly the same spot, and catch the next ball without moving. The largest of the lot sported a 12-foot throwing arm and a 400-pound counterweight. That monster would fire a 5-pound bag of flour into the next time zone. That particular projectile rendered a lovely white explosion on impact. It would throw a softball even farther.
It takes a special kind of guy to climb into fake Roman armor
he made in his workshop and parade around in public with a
massive DIY medieval siege engine. Specifically, it takes the
really nerdy sort.
Showtime
It’s tough to be as weird as I am without drawing a crowd. As a result, Jason and I were invited each year by the Ole Miss School of Engineering to kick off their statewide high school trebuchet competition. Teams from across the state build trebs and then come together in the Vaught-Hemingway Football Stadium to see whose machine performs the best. As ours was hugely bigger, we were the warmup act.
In keeping with the gravitas of the moment, my buddy went as a crusader while I was a Roman legionary. My kids and I made my lorica segmentata Roman armor out of roofing flashing as a homeschool project. I have skinny legs. I looked like Big Bird out trolling for SweeTarts on Halloween, but I still just ate it up. I’ve always been cool that way.
And then, after several years of this, it all stopped. One teeny trivial close call, and my buddy and I never got invited back. Honestly, it could have happened to anybody.
The one thing the University of Mississippi reveres beyond all else has got to be the jumbotron. This gigantic monstrosity is about the size of a skyscraper and adorns one complete end of the massive football stadium. It is the holy altar employed during the pagan rituals that are SEC football games. There is literally no telling what that ghastly thing cost.
We set up the treb in the end zone, a not-insubstantial undertaking considering its size and mass, and got a couple of hundred little mini nerds all gathered around. Once we got the massive throwing arm cocked and the softball in place in the sling, we got a volunteer to snatch the lanyard. When this thing goes off, you can feel the earth move. Seismographs in Nevada record the event. Everything performed exactly as designed. Our leviathan medieval siege engine launched our softball at, conservatively, 5,000 feet per second … straight at the jumbotron on the far end of the stadium.
The crowd held its collective breath. The administrators in attendance representing the engineering school actually briefly died. And then the softball impacted the cheap seats in the student section, maybe five feet beneath the jumbotron. No harm, no foul …
All involved had a great time, though we were forbidden from firing our big treb a second time. We looked like idiots, and the kids learned some things. Inexplicably, the following year, we just didn’t get the email invitation to come back. It’s likely all just as well. I wasn’t getting any better looking in that DIY Roman legionary getup.
