Trebuchets and Tambourines

All right, I lied. There are in fact zero references to tambourines in this post. Nevertheless, I had to do something to get your attention so I could introduce myself as the tardiest of the new student bloggers! My name is Chris, and I am the second of the new freshman bloggers, joining our very own Colin. I will not even bother describing my many and varied interests, from computers to catapults to business and puppies (but I seldom exercise all the possible combinations of those).

Thus, I might as well jump right in to the overall point of this post: To tell you about an excursion I had two weekends ago in building trebuchets and launching pumpkins. One fine, breezy, and colorful fall day here in New England, I awoke to the rising sun through my window, and promptly checked my email for the first of many times that day. At the time, it was unbeknownst to me what I would encounter...

ASME Announcement

I knew I had to do it. How could I possibly turn down the opportunity to throw pumpkins across ridiculous distances using absurdly over engineered devices that would likely deprive me of sleep for the better part of weekend just to build? It was an offer I could not refuse. Within days, a team was assembled, plans were drafted, and devious actions began to get underway. At the very least, we hoped our device would smash the pumpkins (or itself) in a spectacular way. When the fortuitous day finally came upon us, we were ready. We were prepared to offer our blood, toil, tears, and sweat to wage war upon the pumpkins by sea, land and air, with all our might and with all the strength Olin's power tools could give us.

However, that was only the beginning. We had no idea what to possibly expect. After the challenge formally started, we decided on our final trebuchet design around 3pm (other teams did an air canon and a slingshot), and then waited until 8pm to do a Home Depot run for supplies. Before I discuss the sheer scale of our trebuchet, let me show you the rough CADD sketch I put together:


We did modify our design somewhat from this sketch, which also does not include a sling, trough, or weight container, but that represents a 16' throwing arm, 12' long base, and 8' tall trebuchet. We designed our weight container afterwards to support up to 600 lbs of sand, optimized to a 100:1 ratio for throwing objects. We built through the night, and thanks to daylight savings time, got to bed at 4am with the majority of our parts built, but not constructed. It was quite a unique experience building a trebuchet in the middle of the Olin 'O' for several hours straight in the dark, with work-lights rigged on a 2x4. The next morning between 11am and 4pm we brought all of our parts down to some of Olin's Parcel B, and setup the siege engines in the middle of our autonomous vehicle-testing track. After bending a 1" steel pipe on our first weighted launch with only 150 lbs of counterweight, we proceeded to optimize our sling design and try to get the trebuchet to launch. It eventually succeeded, probably getting us between 50 and 100 feet, but with a crack developing down the center of the throwing arm once we added more weight, it was time to call it quits.


Overall though, my experience two weeks ago was one of the most unique spans of ~30 hours that I have ever experienced. It brought me back to old memories of Junkyard Wars and classic Mythbusters. It was also an amazing team experience working with four other people to get such a tremendous project done. Moreover, it gave me great ideas for trebuchet mk.ii, expected to make its debut sometime potentially possibly in the vicinity of maybe the Candidate's Weekends next year.



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