Wielding the power to melt glass or instantly ignite most day to day materials can be intoxicating pretty fun. With a little math, a lot of patience, and 5,800 1cm pieces of mirror, this build requires welding glasses just to look at the 1-2cm focal point. With an idea rumored to date back to Archimedes, this more portable parabolic project is perfect for your home burning needs. Unfortunately, this setup seems to have burnt itself to death at some point, though that makes room for version two, which will reportedly bump the mirror count to 32,000 or so.
There are plenty of other ways to make a death ray out there as well, including using lasers or lenses. Think you have a better tool of destruction? Be sure to tell us about it.
German engineering firm Festo has created this flying manta ray. Dubbed the Air_ray, it’s a balloon made of an aluminum-vaporised “PET foil”. Inflated with helium, the Air_ray’s propulsion system is a flapping wing drive. Each wing has alternating pressure and tension flanks that are attached to an internal set of ribs. The flanks are connected to a remotely controlled servo motor. When pressure is applied to either of the flanks, the wing bends in the opposite direction. By alternating pressure on the flanks, the wings beat. The servos are powered by two 8V LiPo accumulator cells.
The total weight of the Air_ray including the balloon, propulsion system, power supply, and helium is 1.6Kg. Festo has more specs in this PDF.