A few months ago we featured a model aircraft whose power plant came courtesy of an angle grinder. It was the work of [Peter Sripol], and it seems he was eseiged by suggestions afterwards that he might follow it up with a helicopter built using a Dremel rotary tool. Which he duly did, and the results can be seen in the video below the break.
The Dremel itself requires a gearing to drive the balsa-bladed rotor, and a tail rotor is mounted with its own motor at the end of a boom. The video has many entertaining failures which see him arrive at a set of balancing arms and a tailplane for stability. The result is a helicopter that flies after a fashion, and is even able to stay aloft for a few seconds rather than crashing to earth.
The machine lacks the full rotor pitch control of its commercial bretheren, indeed the only control is directional via the tail rotor. Still it deserves top marks for entertainment alone, and we wouldn’t mind a go ourselves. The original angle grinder craft can be seen here.