Today was the carnival, with the cardboard boat race and the soapbox derby and-- most awesomely-- the trebuchet contest. I thought about trying to get one built, but I realized that two weeks was not enough time, and that though they would reimburse me for building materials, I really didn't have the money either. I think I will do one next year.
The weather couldn't have been better for it, bright and sunny but not overly hot-- I wish I had brought sunscreen, though, as I am somewhat burnt now-- and the whole day was a lot of fun. We did not go to the boat race, but got there in time to see the trebuchets doing their calibration shots. There were seven or eight of them, mostly traditionally designed, some floating arm, and one... well. They called their machine "Ambitious Rubbish" and it was certainly that, but it was my favorite of them. It broke half the time they tried to fire it, but dammit, they had come up with an original design. Most of the others could have been build from downloaded plans.
A quick lesson on trebuchets: A trebuchet has two important features, a counterweight and a throwing arm. Most are built, as they were historically, so that the counterweight is on one end of a long, rotating beam, and a sling is attached to the other end. The counterweight is raised, and the sling loaded, and then the counterweight will be released. The counterweight is usually something like sixty times the weight of the ammunition, and so it whips the throwing arm around, flinging the ammunition with a lot of force. A floating arm trebuchet has one rather important change: the counterweight is not attached to the end of the throwing arm. Instead, it is allowed to fall straight down. These are much harder to build, but have a better power output because less energy is lost.
"Ambitious Rubbish" had taken the idea of the floating arm, but had not built it on a vertical track like most. It had a counterweight that dropped vertically, and a separate throwing arm (which had been constructed rather strangely to accomodate the elaborate pulley system they used to raise the counterweight), but in many respects it looked more like a traditional trebuchet. They also had all their power tools, duct tape, and extra wood, in case they needed to repair it... which they did, several times. It pulled itself apart, hit itself with its own counterweight, and, when they did manage a launch, the box they had been using as a counterweight broke from the weight that was in it. They only launched successfully twice, and one of their misfires went backward into the crowd. (Several others had that problem as well, one of them breaking irreparably in the process. This one wasn't the worst of them, just the most interesting.) But I liked it, because the team had actually tried to do something new, on their own.
The best one, of course, was one of the floating-arm types, which probably had a lot more money and time and skill put into its construction.
The competition was interesting, too-- most of the time, such contests are about distance only, seeing who can launch something the farthest. Not ours. Instead, they are given a target, and the target will be set at five different distances. So the trebuchets had to be built for accuracy instead of just distance, and had to be adjutable. Adjusting a trebuchet's distance is fairly easy-- change the weight of the counterweight. Knowing how MUCH to change it is a bit harder, so even the best team didn't hit the mark every time. More often than any other, though. They also had the fastest reset, and in general just seemed to know what they were doing more than anyone else. But they were not my favorite. Competence is great, but it's not always as fun to look at.
After the trebuchet launch we wandered a bit, saw what else was going on. At the soapbox derby there was a car made of a kayak, and one with a couch on it, and one that had its own stereo system. They had brought in donkeys for some kind of obstacle course-- the Burro being our mascot, that makes some sense. There was a mining competition we didn't go check out, but for which there was an ambulance waiting, just in case. There were little carnival games of all sorts, set up by various campus groups. There were inflatable carnival games. In lieu of the large set up where you try to hit something with a hammer hard enough to ring the bell, the geophysics kids had brought out a thing that sensed sound waves through the ground, and used an oscilloscope to measure how hard you'd hit. There was face painting, and free food for students, and cotton candy. And there was of course beer, provided by Coors, for a dollar a glass. Oh, and there was a car show, elsewhere on campus.
All in all, it was a lot of fun, and I'm glad I actually went this year.
The weather couldn't have been better for it, bright and sunny but not overly hot-- I wish I had brought sunscreen, though, as I am somewhat burnt now-- and the whole day was a lot of fun. We did not go to the boat race, but got there in time to see the trebuchets doing their calibration shots. There were seven or eight of them, mostly traditionally designed, some floating arm, and one... well. They called their machine "Ambitious Rubbish" and it was certainly that, but it was my favorite of them. It broke half the time they tried to fire it, but dammit, they had come up with an original design. Most of the others could have been build from downloaded plans.
A quick lesson on trebuchets: A trebuchet has two important features, a counterweight and a throwing arm. Most are built, as they were historically, so that the counterweight is on one end of a long, rotating beam, and a sling is attached to the other end. The counterweight is raised, and the sling loaded, and then the counterweight will be released. The counterweight is usually something like sixty times the weight of the ammunition, and so it whips the throwing arm around, flinging the ammunition with a lot of force. A floating arm trebuchet has one rather important change: the counterweight is not attached to the end of the throwing arm. Instead, it is allowed to fall straight down. These are much harder to build, but have a better power output because less energy is lost.
"Ambitious Rubbish" had taken the idea of the floating arm, but had not built it on a vertical track like most. It had a counterweight that dropped vertically, and a separate throwing arm (which had been constructed rather strangely to accomodate the elaborate pulley system they used to raise the counterweight), but in many respects it looked more like a traditional trebuchet. They also had all their power tools, duct tape, and extra wood, in case they needed to repair it... which they did, several times. It pulled itself apart, hit itself with its own counterweight, and, when they did manage a launch, the box they had been using as a counterweight broke from the weight that was in it. They only launched successfully twice, and one of their misfires went backward into the crowd. (Several others had that problem as well, one of them breaking irreparably in the process. This one wasn't the worst of them, just the most interesting.) But I liked it, because the team had actually tried to do something new, on their own.
The best one, of course, was one of the floating-arm types, which probably had a lot more money and time and skill put into its construction.
The competition was interesting, too-- most of the time, such contests are about distance only, seeing who can launch something the farthest. Not ours. Instead, they are given a target, and the target will be set at five different distances. So the trebuchets had to be built for accuracy instead of just distance, and had to be adjutable. Adjusting a trebuchet's distance is fairly easy-- change the weight of the counterweight. Knowing how MUCH to change it is a bit harder, so even the best team didn't hit the mark every time. More often than any other, though. They also had the fastest reset, and in general just seemed to know what they were doing more than anyone else. But they were not my favorite. Competence is great, but it's not always as fun to look at.
After the trebuchet launch we wandered a bit, saw what else was going on. At the soapbox derby there was a car made of a kayak, and one with a couch on it, and one that had its own stereo system. They had brought in donkeys for some kind of obstacle course-- the Burro being our mascot, that makes some sense. There was a mining competition we didn't go check out, but for which there was an ambulance waiting, just in case. There were little carnival games of all sorts, set up by various campus groups. There were inflatable carnival games. In lieu of the large set up where you try to hit something with a hammer hard enough to ring the bell, the geophysics kids had brought out a thing that sensed sound waves through the ground, and used an oscilloscope to measure how hard you'd hit. There was face painting, and free food for students, and cotton candy. And there was of course beer, provided by Coors, for a dollar a glass. Oh, and there was a car show, elsewhere on campus.
All in all, it was a lot of fun, and I'm glad I actually went this year.
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