Rubber Band Powered Submarine!

grabcad

To my surprise, I decided to make a water torpedo for my son, though I couldn't remember why. He agreed enthusiastically, so we proceeded. It turned into a submarine-like toy, printed using my Rostock v2 Max 3D printer. The propeller shaft is made of .040 inch piano wire, and the ends are safely hidden inside the prop or hull to protect little fingers. To ensure safety, sand the ends smooth or hide them within an object. Assembling with rubber bands isn't difficult; using a bent music wire hook and needle-nose pliers can help. The thrust bearing beads come from Michael's craft store, with item numbers 257901, 89734-2014-08, and 86946 16988. Despite some friction in the system, the torpedo can travel several feet through water or across a bathtub. Its hull rolls in opposition to propeller torque, but it's just a fun toy! Enjoy printing and playing with your kids.