Catapult - Science-Project-a-pult

thingiverse

My boy and I conceptualized this catapult, inspired by an onager or mangonel design, for his sixth-grade science project. It's built to be modular and glue-free, with only a quarter-inch rod required for the main axle, as well as two eighth-inch pins for the bucket. The bucket can be moved along the arm lengthwise to test the effect of arm length on throwing dynamics. It can also potentially be angled one way or the other to analyze how various inner profiles influence the release trajectory. Additional rubber bands can be incorporated, but we determined that more than one became a "no-mom-knew" issue. Two frame parts, two spacer elements (located alongside the arm when the axle is inserted), two secondary reinforcement bars (underneath the main frame's ends), and all other essential components must be printed. I opted for ABS material with low infill density but thick outer shells to maintain elasticity. Our experiment revealed that dense infill resulted in breakage, so I adjusted our design accordingly.