I had been wanting to build a trebuchet for a long time. Probably since I first played Age of Empires II when I was about 9 years old.
In the last few years, I’ve drawn sketches and dreamed of plans to actually build one, but they never came to fruition due to the low priority on the list of things that were on fire during engineering school. Then suddenly and unexpectedly, my Integrated Manufacturing & Design course gave the option for our group to build a Trebuchet. So obviously I did a cartwheel and signed us up.
My group thought I was strange for already having extensive knowledge on classical siege warfare. Finally those nights of staying up way too late reading about useless information actually came in handy.
Our design spiral spiraled through all the different trebuchet types, and we decided to settle on a classical style over the Merlin or falling arm styles. We used the Virtual Trebuchet to get a rough idea on what type of dimensions we would need to achieve the required 150ft launch of a golf ball into a garbage can.
Since the class was titled “Integrated Design & Manufacturing” the project was meant to be a design and manufacturing exercise and not an adventure into classical dynamics. So with that said, the only manufacturing requirement was that at least one part had to be CNC milled.
I modeled the trebuchet in Solidworks. Most of its construction consisted of typical 2×4’s and some 1×4’s too. A 5/8″ steel rod was used as the pivot and re-purposed leather from an old couch along with some nylon rope served as the sling.
It was pretty fun to build. We were criticized by our professor for using wood in a manufacturing class. While we weren’t the only ones to use wood, some other teams used PVC and metal pipes to build theirs. Wood made the most sense to us for a trebuchet. Its just how it should be done.
So you’re going to CNC the gusset plate… and the rest is just an exercise in carpentry?
We never actually landed the golf ball in the trash can, but came really freakin’ close a bunch of times. The distance was no problem at all. In fact we had to take some of the sand out to get closer to 150ft. Out of about thirty shots, most landed within 5ft of the can. About 5-8 landed within 1ft. We decided it was statistically plausible and called it a day. We could have been there all week trying to get it in, and variables like the wind were out of our control.
Check out the video