The Trebuchet Page
Pictures are courtesy of Usa-Kusa
These are the message that were left on the message board, that the writer gave me permission to publish.
"I'm building my own trebuchet for a school project but am having a heck of a time finding actual plans for one. I need one that uses a free weight and one that uses a fixed weight. Please help is possible somehow!!!"
Trebuchetguy: Most designers do not actually create individual plans for there creations. If is a small one my best advice is to design one yourself! Start small, look around the net for the general idea and add your own slant on it. Draw it out on paper first. After it is built I suggest modifying it for a superior engineering. Record your results in a log of some kind, and take your observations into account when you build your next one. It is a long but enjoyable process, and well worth it in the end. If you need more detailed help feel free to write back.
"My counterweight is malfunctioning. I have attempted to increase the pull factor, but to no avail. Please help me with my situation.
Trebuchetguy: I would like to know this, how can a counterweight malfunction? It is just a object with a large mass that falls to the ground by the force of gravity. Write back and tell me how.
"Well, like I said, I'm trying to increase
the pull factor on my latest treb. this monster is a 50-foot deal that cost me
$2000 in building supplies. So, I'm now looking for a substantial counterwieght
that can launch huge objects, such as an old car frame i came across. I
reinforced the launch shaft with stipulated rivets, so I'm not too concerned
about breakage there. In order to launch an object this massive (don't worry,
its not a standard car frame... its about half the length of a standard auto...
I got it from a Berlin based comany's parts auction. they call em ""coffin
cars"" over there)
I'm Catapult Calypso, hired by trebuchetguy to answer complex questions such as those that you have. Being a professional in this category, I will explain everything! Your PPSI formula off scale and needs more description. I cannot do anything with the current information given to me. The total density of the counterweight should consist of lead-bromide formula. (PbBr). This should work quite well under great pressure. Were talking about 500 Torr. You could order such heavy amounts of PbBr at www.metal.com. They have everything you need! In the future please be more specific about your "dilemmas" and don't beg to be put on my web, you're just askin for trouble!
-Catapult Calypso- (professional nuclear physic)
A big piece of metal usually works unless you are building a traction trebuchet.