This is my second wooden, hanging counterweight trebuchet and the first well-documented one. It will be bolted together from many self-designed and self-constructed components, each about six feet in length. Hopefully, that strategy will allow for some degree of siege mobility and make fixing broken sections of the device far easier. Oh yeah, a trebuchet is a medieval-era siege weapon capable of hurling a variety of things great distances, inducing feelings of pleasure (in me anyways).
I want to hear your trebuchet tips! This project is just starting and will be updated gradually as things progress; I'm sure there's some latent treb-knowledge in the heads of many Instructablers. Let me know what you think of current plans and where you'd like to see the trebuchet go. Favorite arm-ratios, clever trigger systems, winching mechanisms, sling designs...I'd love to try implementing them. I've never attempted a large scale floating arm trebuchet, but if you're convincing enough, I just might. If you'd like to be a collaborator, let me know and I'll try to add you on.
Also, I'm an enormous SketchUp fan. I'll try to present screenshots of any models I use but viewing and helping with this Instructable will be easier if you just download the (free) software here.
This page will also carry the breakdown of the trebuchet's cost (see the Excel file below). As of my last expenditure on April 27, 2007 I've spent $315.
This here Intro page will be the resting spot for the most current model of the entire trebuchet.
A warning to fellow siege engineers: This project can be considerably dangerous, given the gravitational energy of these things and the fact that it is a weapon. Exercise great caution if you decide to build a trebuchet of any size--smaller models (like this) should be attempted first to get a sense of their operation.
Last note! The Sourpuss Trebuchet is a major inspiration to this project; a final product half as good as their device would be incredibly pleasing. The Dr. Seuss Treb should also be cited for it's poetic awesomeness.
Step 1: Base: design (I)
This step will cover my design for the long end of the base (the entire base will be rectangular in shape, I think; the short ends will be covered in part II). The plans for one of the long ends can be seen in the SketchUp file. As each long end of the rectangular base is identical, this design will just be built twice.
I wanted a slot in the middle of the base to help align the main vertical support when it is put in place (this whole thing is modular, remember). Have no fear, more bracing than 5.5" of pine will be made for this vertical support later. The total length is 18' and I decided to go with 2x6's (which are in fact 1.5" x 5.5", just to make that clear) just cause they seemed pretty sturdy... These long lengths of the base are 3 2x6's wide (aka, essentially invincible).
The screenshots of the SketchUp file below give the whole picture (it's pretty simple). Each section--red, blue, and purple--will overlap by 16" and be bolted through to secure all three pieces into one component. It helps later to remember that every offset made in this part is 16". Note that the red and purple section are identical (whoa!). The blue section looks kinda tricky but just check out the dimensions, don't forget about the 5.5" slot, and remember the overlap/offset 16" rule.