Figure 1. Do not get discouraged if at first your trebuchet launches the eraser straight up in the air or fails to release it at all. Finally, watch your trebuchet … Basically a one-man traction trebuchet, it was used by emperor Nikephoros II Phokas around 965 to disrupt enemy formations in the open field. We've done this with success on all our trebuchets, We bought two basket ball Measure the diameter of the object you want to throw. The next animation demonstrates how the forward motion of the entire trebuchet adds to the power of the rotating beam and sling. You should be able to tinker with your design a bit (see recommendations at the end of the procedure) to get your eraser to launch. The trebuchet is a medieval rock-launching catapult used to destroy enemy fortresses. Treb Jr's sling is made of denim. available. An important part of any good Trebuchet is the sling. Measure two lengths of rope the same as the distance between the fulcrum and release hook of your trebuchet. Gurstelle has built plenty of trebuchets, including a DIY design using wood and PVC that he named "Little Ludgar" after Edward's trebuchet that leveled the Scots. From the “long arm,” a sling holds the payload usually a rock. One modification to what jfriberg said: The arm doesn't have to stop, and on a trebuchet typically doesn't. isn't heavy enough. In addition, we always tie our sling line a short distance from We have had many pouches, and several have proven useless after a One subsystem of the trebuchet that could be modified is the frame. A must read. This is not a trivial task given that there are many variables one can adjust. Reconstructed trebuchet at Château des Baux, France. With the brace's height's only limitation was our mitre saw's angle of 50º, we put brackets in the corners and we had a trebuchet frame. Sew a line between the two points. described pouch. But to get a trebuchet to work to its maximum potential requires having the right kind of sling pouch for the object you are trying to throw. To begin, enter the parameters of your trebuchet in the input boxes on the left. Some things that you should also checkare the dimensions of the trebuchet, the weight of the projectile, the wheels of the trebuchet, and the wind. This makes sense intuitively since range is a key factor when staging an attack on an enemy. made. A trebuchet is a long-range weapon that uses a swinging arm to send a projectile toward a target. After pulling several grommets on our trebuchet, I opted to have Amy Onager slings have the same issues as those for the trebuchet. You can easily make your own 2 ft (0.61 m) tall trebuchet with a few materials, and you can scale the measurements up or down to create one that’s your desired size. In this case, use a large pouch for them. Gizmo Warm-up A counterweight trebuchet acts like a giant see-saw. projectiles, Roger came up with this one. A well-built trebuchet should be able to hurl an eraser a few feet. is possible in the throwing beam. the same way a golf ball can float longer with top spin. of fabric where the grommets are set. the distance from the fulcrum to the release hook. This is the second sling made for this machine since the holes in the This design project allows students to use the engineering design process to research, design, and build a trebuchet. It should also allow you to release the trigger using a rope or string from a distance. This sling was also used with our larger counter weight trebuchet Reinforce the ends of the pouch with extra canvas before inserting the grommets if you are throwing heavier objects. The beam pulls the sling. As the sling swings out, it attempts to go straight with the arm. The previous two both had the Since then, she has worked as a writer for broadcast news and volunteered her writing skills to several nonprofit publications. Cut the rope and tie the ends through the grommets of your pouch. The counterweight, arm length, and projectile size. The advantage to a In the Trebuchet Gizmo™, you can design your own trebuchet to attack a city or castle. A sling, which has a pouch containing the projectile, is attached to the long end of the beam. But to get a trebuchet to work to its maximum potential requires having the right kind of sling pouch for the object you are trying to throw. There is a lot to think about when you go to design a trebuchet. Counterweights were of two types: fixed or hinged. stitches might pull out, but it just ripped right through the canvas. The length you need is a combination of The counter-weight uses the pull of gravity to provide the force necessary for the arm to swing upwards. This pouch was made by Amy for Juggernaut, and is just the right size Fold the diamond in half width-wise so that the grommets are together. energy imparted to it. In addition to building prototypes of a trebuchet, you can also use physics calculations or even a computer simulation to help you design it to have the best range. Lots of folks envision some sort of complicated mechanism when the reality is very simple -- just centrifugal force pulling the free end of the sling off the pin.