If you thought 3D printing pens were just interesting toys, here’s something that might change your mind, a freehand 3D printed quadcopter propeller. The way it was made was quite interesting, and would be tough, if not impossible to duplicate with a “traditional” 3D printer. The surface of the original blade was simply traced with a 3D Air Pen to make the basic shape.

After the basic shape is created, the central hub, which needs to be thicker than the blades, is built up using a tracing. After inserting this hub inside the wings, everything has to be “3D glued” together. Some “secondary operations” are then done, including drilling and tapping a hole in the hub, and strengthening and balancing the propeller by adding more material. Finally, everything is deburred with a Dremel tool.

Certainly, if you have the time, it would be much easier to simply order a new propeller, but if you need a replacement right now, this could be a viable option. Interestingly, this isn’t the only aerial contraption I’ve written about for make; for another idea, why not check out an entire model airplane frame printed with a similar device. It was able to fly, but not quite as elegantly as this project.