This is a modern version of a medieval siege engine. The difference between this type of a catapult, called a FLOATING ARM TREBUCHET at trebuchet.com, and a traditional version like the paper unit below, is the way the weight falls. In a traditional trebuchet the weight has to fall in an arc, wasting energy as the weight moves horizontally. In this version, the weight only has to fall vertically, futhermore the weight can fall a longer distance because the arm dosen't have to pivot around a fixed axle. The arm is built so it floats and the whole set up will throw the missile much further than a similarly set up traditional model. This thing will hurl a golf ball over 300 feet using roughly 12 lbs. of weight (concrete in PVC)!!!
Picture 3, 4, and 5 are of the latest version of the F2K. I rebuilt it, sloped the rails 20 degrees, increased the throwing arm length, and increased the distance the weight drops. Also in the picture is an F2K built from plans from trebuchet.com.
This is a trebuchet made from card stock. We throw dice but anything about the size of grapes will work equally well. Using the weight of about 100 pennys, this model hurls the dice across the living room. You can download the plans for this paper treb from Fryer's Kits (looks like the link is dead these days, you can email me and I'll send them to you)
Another of Sheyenne's science projects is a Rube Goldberg machine. Click here to watch a small .avi video of the machine in action.
last updated 01/16/2006