Drone helicopters join to form multi-rotor UAV

Researchers at the ETH Institute for Dynamic Systems and Control in Switzerland have developed a robotic vehicle that flies successfully when a number of single-rotor units join together to create a multi-propellered system

In order to fly a number of single rotor units join up with one another to form a viable aircraft. Individually the units are unable to fly but this changes when they join up and co-operate in order to fulfill their mission.

More details - and videos - can be found here.