History & Physics
The Klingon chetvI'
Bagelchucker and The Great Bread War
As part of the Three Rivers Arts Festival in June, performance artist Carlos Szembek planned an instillation consisting of a small bakery and a huge slingshot. His plan was to hurl the loaves at the USS Requin, a WWII submarine permanently docked at the Carnegie Science Center. A sort of "Bread not bombs" political statement.
I had wanted to build a traction trebuchet for some time but his targeting of my workplace galvanized me into action. I had a week and a half to muster a response. I intended to build a machine like the Grey Company's traction treb with a 15' arm and a crew of six. If it would throw a 2 lb. mass 200 yds, how far might it throw something lighter?
I went to the local SCA barony meeting to gather a team of engineers. Unfortunately, the team assembled had their own ideas about the machine they wanted to build and constructed a machine with an arm too heavy for the mission objective: returning bread for bread. My desire not to re-invent the siege engine and simply copy the Grey Company design was for naught.
So, with five days remaining, I set about building a one-man traction treb. It's arm would be 10 ft long, the axle a little over a foot from the pulling end set 7 ft off the ground. I would test this machine with a tennis ball as the projectile in preparation for the actual weapon of choice; bagels.
Two days before the event my treb was completed, sitting in my driveway. I loaded up a tennis ball for its first test, expecting it to throw high into a tree or low into my back yard.
I have no idea where that tennis ball went. I must have adjusted the release angle perfectly because it whizzed up through the tree, missing major branches, and disappeared into some neighboring yard. Further testing would require wide open spaces so as to recover the projectile and judge its range.
The next day's testing in a local park yielded a range of about 180 feet for a tennis ball. Less that I would have hoped but, I suspected, still be better than my opponent's attempt would be.
D-Day was bright and clear and predicted thunderstorms, as annual an occurance as the art festival itself, were not to be seen.
I set up on a dock near the Science Center, my opponent across the confluence of the Allegheny and Ohio rivers in Point State Park, 1200 feet distant. An impossible range. But I made a go of it anyway, sending bagels spinning 150 feet out into the river.
As for Mr. Czembek, his planned assault was to take place much later in the day, the climax of the art festival. Unfortunately, the number of boaters on the river prompted festival organizers to cancel the event for fear that someone might be struck by a flying bread loaf.
And the Science Center? Almost all I talked to had thought my idea was a great one. Staff and volunteers on the Requin felt slighted by Mr. Czembek's targeting of their honored craft and wanted to retaliate. Yet, they too became fearful of the possibility of bad publicity and would not even walk up the riverside the 100 feet to see what I had done. So much for honor.
You may ask why, with all the plans posted for my other trebs, why there are no plans for Bagelchucker. The truth of the matter is that it was a lousy design. The two tripod supports are not very stable and the machine has a tendancy to want to pull over onto the operator (part of the reason I was wearing a helmet). Take a look at the Grey Company's design and model off of that. Much more stable.
|http://www.tasigh.org/ingenium/bagel.html -- Revised: 27 May 2002
Copyright © 2002 Kevin A. Geiselman