Design
So in the Designs flyout are our different stages of what we have done so far. However, below are some key features and approximations we will be keeping to while tweaking bits and pieces of the structure.
Elements and Rationale
Base:
Approximate dimensions: 1.0m X 0.40m X 0.05m The base will be made of wood and its dimensions will be approximately 1.0m X 0.40m. The base needs to be wide enough that the counterweight may swing down unimpaired as well as long enough that the sling may travel some distance along the glide track. Glide track: Approximate dimensions: 1.0m X 0.20m X 0.01m The glide track will also be made of a thin piece of wood lining the bottom interior of the base. Having a thin piece of wood would reduce the mass of the trebuchet and since it isn’t a supporting component of the trebuchet, it won’t be necessary to have large pieces of wood or plastic to hold a tennis ball. Tower support frame: Approximate dimensions of each upright: 0.05m X 0.05m X 0.70m The tower support frame is approximately 2/3 of the length, so it will not tip over the trebuchet while also being tall enough that the counterweight and the shorter half of the swing arm lever can travel under the fulcrum without hitting the glide track. Swing arm lever: Approximate dimensions: 1.4m X 0.05m X 0.025m The swing arm lever is long on one side so that there is a greater height when the ball is released so that there will also be a greater range. It is also shorter on one side so that the counterweight and lever swings through unimpeded. Counterweight: Approximate mass: 100x mass of projectile The counterweight will be a bucket, probably plastic. The rationale behind this was so that the group may choose to put whatever they want in it. Also since this can be easily purchased at a dollarstore, time and money will not have to be spent creating one out of wood. Also with a bucket it will be easier to change the mass inside compared to a cloth holster. Sling (harness): The sling will be connected using a pouch. The sling will reach approximately ¾ of the way across the glide track so it has sufficient to build up velocity. Also, with a long sling the range will be improved since at its apex it will have a greater height than a smaller trebuchet. Release Mechanism: Composed of 3 large eye hooks, 2 on the main body of the trebuchet and 1 on the swing arm, a metal dowel will be slid through all three and pulled out for release. Axle: The swing arm will move around a metal tube which would be stronger than wood to prevent cracking. Therefore the tube will be threaded through the two support beams and glued in place, with the swing arm between the two to be able to swing freely. Also the axle will have to be greased to reduce friction. |
Picture Examples |