Flying drones with 3D printers attached to their body: it was only a matter of time until the two technologies met. Such a thing now exists, although we're not quite sure it's earned its printing qualification yet. Developed by a team at the Imperial College London, the "3D printing Micro Aerial Vehicle (MAV)" is a quad-copter that carries two chemicals that create polyurethane foam when mixed. Scientists say the foam can be molded to create non-complex structures or repair components, making the drone especially useful in hard-to-reach areas. The substance is also extremely sticky, which allows teams of drones to work together to remove dangerous objects from hazardous locations. Like the video below shows, the quad-copter can swoop in and "print" a layer of sticky foam, which will then stick to the underside of a bigger and more powerful drone so it can be transported away.

Scientists drew inspiration from nature when developing the MAV, mostly notably the the swiftlet. The swiftlet is a small bird that builds nests entirely from threads of their saliva. Right now, the drone can only fly in controlled environments using sensors that feed real-time information back to a laptop. The next step will see the team equip the quad-copter with high-speed cameras, sensors and even solar panels, allowing it to fly autonomously and charge itself in any environment.