During World War I, the United States felt they were lagging behind Europe in terms of airplane technology. Not to be outdone, Congress created the National Advisory Committee for Aeronautics [NACA]. They needed to have some very large propellers built for wind tunnel testing. Well, they had no bids, so they set up shop and trained men to build the propellers themselves in a fantastic display of coordination and teamwork. This week’s film is a silent journey into [NACA]’s all-human assembly line process for creating these propellers.
Each blade starts with edge-grained Sitka spruce boards that are carefully planed to some top-secret exact thickness. Several boards are glued together on their long edges and dried to about 7% moisture content in the span of five or so days. Once dry, the propeller contours are penciled on from a template and cut out with a band saw.
Continue reading “Retrotechtacular: The Construction of Wooden Propellers”
Engineers trying to be memorable at a job interview would be wise to pull one of these pop-up robots out of a wallet. This marvel of engineering uses a laminate construction technique to build a robot as a pop-up assembly. You can see the base used during the process, it’s a hexagon that serves as a scaffolding during the laminating process, and includes mechanical linkages that facilitate assembly.
The design calls for multiple layers of materials to be laser-cut to exacting specifications. Once all parts are completed, they are stacked using rods to align them, then fused together. One more trip through the laser cutter finishes the milling and the machine is ready for assembly. But with parts this small, you’ll want a solid method for putting everything together. The linkages we mentioned before allow for this when two parts of the scaffolding are separated. The only thing that makes this impossible as a business card is the need for a trip through the solder bath to cement the pieces in place. But perhaps some type of clasping mechanism could remove this need in the future.
Don’t miss the video after the break that explains the entire process. You’ll even get to see the little guy flap his wings. That’s all that it does for now, there isn’t any steering mechanism available as of yet.
Continue reading “Pop-up dragonfly robot could be the future of business cards”
The earliest bicycles were made from wood. Nearly two centuries later, some garage tinkerers still turn to this most traditional of materials for their own creations, since welding one requires experience and tools beyond the reach of many. Resembling Gilligan’s Island props, the resulting bikes are both artistic and great fun, but not very practical for real use; often heavy, ill-fitting or lacking durability.
[Boris Beaulant’s] birch laminate Zelo, on the other hand, has cleaner lines than anything you’d see in an IKEA showroom. Not content with an ordinary two-wheeler, he’s tackled a three-wheeled recumbent trike, which requires even finer tolerances. Two months and over 1,300 miles later, the trike is still rolling strong through the French countryside, proving its mettle as legitimate transportation and not just a garage novelty. [Beaulant’s] build log (Google translation here) offers some insights into the development of this masterpiece, starting with prior woodworking projects (furniture, rolling toys and a children’s bike) and finding clever solutions to problems such as creating a mold of his own back for a custom-contoured seat.