We've seen robotic aircraft fly around on helicopter blades, ducted fans, jet engines, and turbprops. But here's a novel type of propulsion, for even the most jaded drone-watcher: paddlewheels. According to New Scientist, for small-scale vehicles the peculiar design – first dreamed up, more than a century ago – should be more efficient that rotor blades*.* That is, if they can ever get the things stable. Right now, they're still attached to tethers.
Here's a video of the paddleboat drone taking off:
www.youtube.com/watch?v=&rel=1
