This technique could come top down / bottom up.
Top down to 2 nanometers or less with metamaterial superlens able to focus to 1/20th of wavelength and maybe less.
Bottom up with directed self assembly and other techniques for making 2 nanometer nanoblocks.
In rapid prototyping, a three-dimensional design for a part - a wing strut, say - is fed from a computer-aided design (CAD) system to a microwave-oven-sized chamber dubbed a 3D printer. Inside the chamber, a computer steers two finely focussed, powerful laser beams at a polymer or metal powder, sintering it and fusing it layer by layer to form complex, solid 3D shapes.
The technique is widely used in industry to make prototype parts - to see if, for instance, they are the right shape and thickness for the job in hand. Now the strength of parts printed this way has improved so much that they can be used as working components.
"The big advantage over conventional, large-scale aircraft production programmes is the cost saving in tooling as well as the order-of-magnitude reductions in fabrication and assembly time."
By mixing composite polymers with radar-absorbing metals, it is thought that the aircraft can be built with a certain amount of stealth characteristics already built in.
The flexibility lent by 3D printing allowed Mauro's team to design and build the Polecat in only 18 months. "Today's sophisticated UAVs are approaching the cost of equivalent manned aircraft. Polecat's approach is a way to break this trend and demonstrate affordable UAV systems that can be rapidly developed," says Mauro.