Day 07 - Begin Building Prototype Trebuchet

The first step in building your trebuchet is to build the beam. This is the lever that will have a counterweight at one end and a sling at the other. The pivot point (fulcrum) should be fairly close to the counterweight end, to ensure maximum velocity of the sling during operation. Your sling should be no more than the distance from the far end of the beam back to the pivot point.

You are expected to be able to explain the trade-off between input force and output velocity; trebuchets make unusual use of mechanical advantage by using a design with an M.A. of 1/5 to 1/7 or even less. You will be required to calculate your M.A. and weigh the load (a small Lego wheel I will provide) so that you will know exactly how much mass needs to be in the counterweight at a minimum.

Once the beam is built, you should design a way to attach the counter-weight and fit an axle through the pivot-point, then build your frame around the axle such that there is room for the counter-weight to freely swing through the bottom of its arc.