This robot flies like jellyfish swim.

BBC describes the first drone that can hover by flapping its wings:

The work by Leif Ristroph and Stephen Childress from New York University (NYU) is published in the UK Royal Society journal Interface.

Most efforts to build stable flapping-wing aircraft – or ornithopters – have based their designs on the way insects fly.

But this approach leads to aircraft that are inherently unstable, tending to flip over if left to their own devices.

Stabilising these designs requires either active control systems, or the addition of sails and tails that act as aerodynamic dampers.

Using jellyfish as one inspiration, the researchers set out to achieve stable hovering using flapping wings alone.

They developed a 10cm prototype with four distinct wings that demonstrated an inherent tendency to remain upright during flight.