This video documents the ambitious project of designing, building, and testing a large-scale, rubber-band-powered submarine with the goal of achieving extreme endurance. The creator fabricates the submarine using a large-format Bambu Lab H2S 3D printer, focusing on a hydrodynamic design. The project follows an iterative development process, beginning with a purely mechanical version featuring an auto-dive mechanism that proves difficult to tune. Through systematic testing, the creator analyzes the breaking points and torque characteristics of rubber bands in various configurations. This research informs the creation of a second-generation model with a gearbox for longer run times and, ultimately, a sophisticated third-generation submarine equipped with an electronic depth control system using an Arduino, a pressure sensor, and a waterproofed servo. After successful tests in pools and clear springs, the final version is put to the ultimate test in an attempt to cross a lake, which ends with the submarine sinking and being lost.
Building and Testing a Rubber-Band Powered Submarine
0:00 Project Goal: The creator sets out to build a large, rubber-band-powered submarine capable of long-endurance runs, aiming to cross an entire lake.
0:36 Design and Fabrication: The submarine is designed to be hydrodynamically efficient and is 3D printed using a large-format Bambu Lab H2S printer.
4:59 Mechanical Auto-Dive Feature: The initial prototype includes a mechanical system where the torque from the wound rubber bands forces the dive planes down. As the tension unwinds, the submarine is designed to automatically surface.
6:42 First Open-Water Failure: During the first lake test, the submarine dives successfully but the mechanical auto-surface feature fails, and it dives too deep. Over-winding also causes the rubber bands to snap.
9:53 Endurance-Focused Gearbox: To achieve longer run times, a second version is built with a 4:1 gearbox. This allows the rubber bands to unwind more slowly, translating their energy into a longer, more controlled propulsion.
11:46 Scientific Rubber Band Testing: A custom Arduino-powered counter is built to test the breaking point of rubber bands. Key takeaway: A single band breaks at ~300 turns, two in series break at ~600 turns, but putting bands in parallel significantly reduces the number of possible turns due to friction.
18:24 Electronic Depth Control System: Frustrated with the unreliable mechanical systems, the creator develops an advanced electronic auto-dive module using an Arduino, a pressure sensor, and a waterproofed servo to precisely control the submarine's depth.
21:45 Perfected Performance in Pool: In a controlled pool environment, the submarine with the new electronic system demonstrates flawless performance, holding its target depth perfectly.
24:35 Success in a Natural Environment: The final submarine is tested in the clear water of Weeki Wachee springs, where it successfully navigates the natural environment while maintaining its programmed depth.
27:51 The Final Endurance Run: For its ultimate test, the submarine is wound 1,006 times and launched across a lake. After a long and successful run, it suddenly dives deep and is lost, likely due to a leak in the electronics pod caused by water pressure at depth.