London: 3D printers could soon create the perfect insect wing, a feat perfected by nature over millennia.
The Pentagon’s Defense Advance Projects Research Agency (DARPA) is in need of micro-aircraft to explore caves and other hiding places and transmit information back to base. And tiny robotic insects would make the perfect fly-on-the-wall snooping devices.
Although miniature helicopters already exist, a flapping mechanism is necessary for making aircraft as small as insects, according to Hod Lipson at Cornell University in Ithaca, New York.
"As you get smaller and smaller the principles of helicopters don’t work, it just doesn’t scale," The New Scientist quoted him, as saying.
The same is true for fixed winged flight.
Even as several researchers around the world have demonstrated flapping machines, wing design can be hit or miss because its physics is difficult to understand and realise, said Lipson. Here’s where the role of 3D printers becomes important - by providing insights on flight dynamics they could be an important step towards the development of smaller and more efficient wings, believe Lipson and his colleague Charlie Richter.
3D printers allow the creation of complex structures, such as wings that are warped to improve performance, like the manually curved wings of a paper aeroplane, said Richter. Their printer can produce features just 16 micrometres wide, and thin films just 40 micrometres thick.
Speed is another advantage of printing, said Lipson. Once they have arrived at a new wing design, printing a set takes less than an hour.
Barring its motor and battery, their latest four-winged creation is almost entirely printed from polyester films stretched over carbon fibre rods. Weighing 3.89 grams, it is capable of hovering untethered for up to 85 seconds.
Lipson and Richter feel their approach could help to take some of the guesswork out of the physics of wing design.
Lipson said: "People understand fixed winged flight very well. But when it comes to flapping - especially untethered, hovering flight, there is very little theory."
Lipson and Richter plan to use their 3D printing approach to cycle through and analyse the performance of a broad range of different wing designs and plug the information into a computer model, which has a genetic algorithm that can then use the data to evolve the perfect set of wings.
Lipson and Richter will present their work at the Conference on Artificial Life (Alife XII) in Odense, Denmark, in August.