What's so special about 3D printers? They make it possible to create complex structures, such as wings that are warped to improve performance, like the manually curved wings of a paper aeroplane, says Richter. Their printer is capable of producing features just 16 micrometres wide, and thin films just 40 micrometres thick.
The other advantage of printing is speed, says Lipson. Once they have arrived at a new wing design, printing a set takes under an hour. With the exception of its motor and battery, their latest four-winged creation is almost entirely printed from polyester films stretched over carbon fibre rods, and weighs in at just 3.89 grams – a six-fold weight reduction on their previous version – and capable of hovering untethered for up to 85 seconds.