A version of Leonardo Da Vinci's catapult design

thingiverse

A friend of mine showed me a box containing a wooden kit for making a model of Leonardo Da Vinci's cataplut that she had bought for one of her grandsons. That was when I first learned of his design. It looked to me to be an interesting 3D printing project, and, after a bit of research on the net this is the result. I've sized the catapult to take indoor (or practice) golf balls. You'll see in the photos that I've designed 3 different 'Side LH' versions giving different angles of elevation. I like the steepest one and it gives a good trajectory when the catapult is on the floor. Designed in Moment of Inspiration, and made entirely of PLA on an Original Prusa i3 Mk2. The screws are all 3mm x 10mm long mushroom head cap screws. A video of the catapult in action is here: https://youtu.be/rkfbdhpfBn0 Print Settings Printer: Original Prusa i3 Mk2 Rafts: No Supports: No Resolution: 0.2mm Infill: mostly 10% Notes: Material PLA. I experimented with different infill percentages for the springs. Those shown in the vidio are 100% ie solid. I think that 50% infill works nearly as well. BTW I did try making the springs in ABS - PLA works better. For all other parts I used 10% infill. Post-Printing Take a little care setting up the ratchet assembly and arm. Leave final positioning of the arm on the 'splines' until you're happy with the string/spring set up. With the springs straight, the screws around which the string runs should be horizontal, and on the side of the shaft furthest from the corresponding spring. Then the arm should be tightened in the 'fired' position. You'll probably need to do some further fine tuning. How I Designed This Found some images of Leonardo's sketch on-line and then 3D designed in Moment of Inspiration (Moi).