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November 19, 2001 Roger and Eric went to Bennington High School where
Eric's Aunt works. Jennifer Rosenthal teaches physics, and is the
teacher who invited us. We brought several models, in addition to
Onager Jr, our onager with a 3 inch rope bundle, and Juggernaut, our 8
foot tall traction trebuchet.
Here is Eric getting the Onager ready to be wound up in the end zone
of the local football field. The onager is tipped up on end to make
it easier to tighten the cord-bundle.
Here is Roger linking the sling onto Juggernaut. We brought two
slings. One made of canvas works well for 20oz soda bottles. The
other one is made from two basketball nets, and is better for the
gallon jugs.
Eventually the students come out. Juggernaut is on the left, and
Onagerjr is in front of the crowd.
An group of kids from the honors class prepare to pull on Juggernaut's
counterweight lines. Eric is preparing the projectile to be launched.
This group of high school students managed to throw 1 gallon of water
somewhere around 160-170 feet down the football field. Team
Tormentum, using a counterweight in the 1998 Punkin' Chunk only
managed a throw of 165 ft. It must have been the excellent
coaching. ;)
There was a wide range of distances thrown by the students. One
team didn't get a single forward shot. The teachers also had a
similar problem. The most important thing to do as a counterweight
is to be unafraid of the ground. Giving up early results in a
backwards release.
The Onager is tipped on end again as some students learn about cord
bundles. Roger is perched on top to prevent the machine from
flipping over when the kids put their weight into it. These students
were amazed at how hard it is to tighten such a small cord bundle.
With enough grunting, they did manage to twist the onager up farther
than it ever had been before, permanently deforming the rope. This
had an estimated 1500lbs of inward crushing pressure on the hole
carriers (based on the working load advertised on the rope.) A side
effect was that a 20oz soda bottle went 160-170 feet. It also
destroyed my new trigger hinge. Oy.
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