Foam-Spraying Quadcopter Becomes a Flying 3D Printer

Zothecula writes "The swiftlet may not look much different than other little birds, but it has one unique ability – it builds its nest out of its own saliva. Inspired by the swiftlet, scientists at Imperial College London's Aerial Robotics Lab have created a robotic quadcopter that can extrude polyurethane foam while in flight. By targeting where that foam goes, it can build up simple structures, essentially becoming a flying 3D printer."