A team, led by Andy Keane and Jim Scanlan of the University of Southampton, believes that 3D printing will soon allow unmanned aircraft to go from the drawing board to flight in a matter of days.
No longer, they say, will one design of UAS be repeatedly manufactured on a production line. Instead, designers will be able to fine-tune a UAS for each specific application – whether it be crop spraying, surveillance or infrared photography – and then print a bespoke plane on demand.
3D printing has come on in leaps and bounds since its origins as an expensive prototyping tool over two decades ago. It uses laser-assisted machines to fabricate plastic or metal objects, building up the item layer by layer, each slice just 100 micrometres thick.
To do this, the 3D printer first slices up an object’s computerised design into hundreds of easily printable layers. Each layer is then “printed” by training a laser beam on a bed of polyamide plastic, stainless steel or titanium powder – depending on the object being created – tracing out the entire 2D shape required for that layer. The laser’s heat fuses the particles together at their boundaries. Once each layer is complete, more powder is scattered over it and the process repeated until a complete artefact is produced.
What the printer spits out is a powdery “cake” from which the desired object can be retrieved simply by pulling it out, like a child yanking a buried toy from a sandpit
To create a stronger object that can withstand higher loads and stresses, an electron beam can be used in place of a laser to melt the powder particles completely. And because 3D printing involves no cutting or grinding of metal, it offers vast design freedom.
This is a huge deal for aircraft designers. Some of the best ideas in aviation history have involved designs which proved too pricey and tough to make. The Supermarine Spitfire, for example, was among the most manoeuvrable fighter aircraft of the second world war because its wings were of an ultra-low-drag elliptical design. But it was a nightmare to produce, requiring complex machinery and production expertise.
“With 3D printing we can go back to pure forms and explore the mathematics of airflow without being forced to put in straight lines to keep costs down,” says Keane. So Keane’s team set out to see how quickly they could design a 1.5-metre-wingspan, super-low-drag UAS, print it and get it airborne. A UK-based 3D-printing firm, 3T RPD of Greenham Common, Berkshire, joined the venture, agreeing to print the UAS out of hard nylon.
“We designed in printable hinges that would let the ailerons move,” says 3T RPD spokesman Stuart Offer. “And we decided where to split the fuselage so the nose could be snap-jointed to the fuselage easily.”
The budget for the Southampton University Laser Sintered Aircraft (Sulsa) was £5,000, which imposed a number of design constraints. The aircraft would have no undercarriage to keep complexity and weight down, necessitating the use of a launch catapult – and a belly landing. It would be electric-motor-powered to eliminate the need for starting equipment and heavy fuel. And it would have a V-shaped tail rather than the usual upside-down-T, so that only two parts had to be printed instead of three.
Cost savings here meant that the plane could have Spitfire-style elliptical wings, as well as a strong geodesic airframe – another expensive second world war-era design, this time from the stout Vickers Wellington bomber, which was extraordinarily resistant to anti-aircraft fire.
On a grass airstrip in the UK’s Wiltshire Downs, north of Stonehenge, half a dozen aeronautical engineers assembled an unmanned aircraft – two wings, a nose cone and a fuselage with a built-in V-shaped tail have been ripped from nylon cakes, dusted down and delivered. Sulsa’s airframe designers Jeroen van Schaik and Mario Ferraro, both grad students at the University of Southampton – which launches a UAS masters course in September – are assembled the aircraft after stuffing it with electronics, servos and batteries.
The plane parts took just two days to design and a further five days to print, making Sulsa a one-week plane. But customising future variants of this ready made design would take minutes on automated design software.
The strength of 3D-printed titanium can equal that of the traditionally machined metal, says Dan Johns, who is printing strong, lightweight metal parts for Bloodhound SSC, the rocket car aiming to break the land-speed record in 2013.
To give a part the required strength, engineers can choose a metal – or mixture of metals and plastics – to suit their needs. For instance, an electron-beam-fused titanium/aluminium alloy elongates 10 per cent before snapping, while laser sintered stainless steel elongates 25 per cent.
“There’s almost always a way to get the properties your project needs,” says Andy Keane at the University of Southampton, UK.
Source: New Scientist
The University of Southampton’s claim needs to be balanced against the reality that numerous companies have been using laser sintering to produce UAS prototypes. There is also at least one company that has been using laser sintering to support series production of UAS airframes for three years and has recorded commercial sales of those same systems – this being CyberTech of Western Australia. Any close analysis of a CyberTech CyberQuad airframe will show the distinctive ‘layering’ signature that laser sintering produces as the airframe is printed. New Scientist magazine’s original report claiming a world first is simply wrong
I believe the Lockheed Martin, Skunk Works designed, Polecat UAV was one of the first UAVs to be built via 3d printing methods (back around 2006).
I’m going to buy a 3D printer, print more 3D printers, sell them and become the richest man ever in the history of 3D printing.Not that I would need the money, as I would be fine in my printed house, with my printed wife and family, eating printed food.And just to be a greedy douche,I’ll also copyright the idea so no one else can do it.