When a helicopter tries to increase its speed or manoeuvre quickly, the airflow over the main rotor can become disrupted. This lowers the amount of lift that the blades can give, and increases the drag forces on the helicopter. This is known as a dynamic stall.

Scientists at the German Aerospace Center found that the humpback whale can move very quickly and acrobatically. This is because they have very large pectoral fins, which have bumps all the way along the front edges. The way that water flows over these bumps means that stalling is less of a problem for the whales.

The researchers glued small 6mm bumps onto an experimental helicopter’s rotor blades, and say that these ‘leading-edge vortex generators’ have already improved the helicopter’s performance.