Rubber band powered race boat

pinshape

This is a high-performance rubber band-powered race boat designed specifically for the Maker Faire 2015 Moat Boat Paddle Battle Challenge. Check out its impressive test run on YouTube at https://www.youtube.com/watch?v=8XWNFfDlJNM. The propeller used in this design is a sturdy store-bought model boat propeller, chosen because consumer-grade 3D printers lack the capability to produce high-strength, high-resolution models that propellers demand. A large pitch propeller is ideal for maximum speed and efficiency. To secure the propeller on the axle, I employed a clever trick: cutting a slot in the tail of the propeller to fit snugly over the head of a 2" T-pin. Autodesk Fusion 360 plays a crucial role in this design process, allowing me to estimate the weight and volume of the model and calculate its buoyancy with ease. To access these features, simply select the body you want to analyze, right-click, and choose "Properties" from the dropdown menu. A handy dialogue box will pop up, displaying vital statistics such as volume, weight, and more. If necessary, feel free to modify the material selection to get a more accurate estimate. Before hollowing out the hull with the Shelling command, be sure to measure both volumes to ensure you're on track. This gives me the precise volume and estimated weight I need to calculate the buoyancy of my model. Using an online calculator, I determined that 1 liter can support approximately 1 kg. To achieve optimal performance, I aimed to make the boat's weight roughly half of its buoyancy. Next, Autodesk MeshMixer comes into play, helping me pinpoint the center of gravity for the model. To fine-tune the boat's balance, I utilized a small stack of rare earth magnets. For added convenience, I drilled a hole in the propeller to hold it securely in place after winding. A convenient loop on the deck allows me to easily retrieve the boat if it gets away during testing. Finally, to minimize drag and maximize speed, I applied a layer of epoxy to the model. Printing requires some support, as evident from the post-print picture below. However, printing lengthwise eliminates any potential issues.