weight of boarder Ross, but also some of his amazing stunts," Oliver de Haas, an expert in thermal insulation and cooling from evico GmbH (which collaborated on the project with researchers at IFW Dresden for the past 18 months) tells WIRED.co.uk.
"The board is very stable when the load is well centred. But it is a bit wobbly around its long axis. This makes it challenging for a boarder to keep it balanced. Using more magnets in the track would make the whole thing more stable, so everybody could ride it -- but it probably wouldn't be as exciting."
"I've spent 20 years skateboarding, but without friction it feels like I've had to learn a whole new skill, particularly in the stance and balance you need to ride the hoverboard," says McGouran, who can be seen nailing that combination in the video, swooping round the park from ever greater heights before finally leaping across ramps (and a Lexus GS F saloon).
The board levitates thanks to superconductors -- made from the catchily named compound Yttrium barium copper oxide -- fitted inside the body. Sitting in two cryostats (or reservoirs), the superconductors need to be cooled to below -181C in liquid nitrogen to work, hence the vapour. Once they've reached this cooled state they can store a magnetic field -- in this case supplied by the 200 metres of magnetic track laid beneath the skatepark.
"So if the superconducting board is cooled down with a small distance to the track in the field of the magnetic track, it memorises this field and generates restoring forces when the board is displaced from its original position, relative to the track," explains de Haas. "These magnetic forces are an inherent feature of superconductors, there is no electronic control necessary and no power consumption for it. Only cooling requires some energy -- [and] less than expected."
The evico GmbH-IFW Dresden team chose this approach to levitation for its "simplicity", says de Haas. "We only have to take care of keeping the superconductors cold." But it had to argue the case to Lexus, which had already been approached by various other companies touting other levitation techniques.
WIRED featured one such alternative technology in the March issue, devised by US company Hendo. It used rotating magnets to generate Eddy-currents in a copper-plate beneath a skatepark surface. The process causes the cooper-plate to heat up and de Haas argues that its energy supply -- from a cable or on board battery -- makes the board too bulky and takes too much energy to power. "We convinced the Lexus team that our superconductor-technology was the best suited for the hoverboard."
Given the excitement around the launch of the hoverboard, their hardwork seems to have paid off, and even led to a few surprises for the engineering team. "We never expected that it could be possible to jump," de Haas tells WIRED.co.uk. "It is not easy to get the board separated from the track. Now we know it is possible."
Despite the momentum around the launch, the team called the experiment a "one-off" and there are no further plans to work on or improve the board for Lexus. "But we are aware to be caught by surprise," de Haas adds, which we're taking to mean 'never say never'…
For now, de Haas is back to his day job: engineering "dust-free and wearless" superconducting bearings for industrial automation, pharmacy or micro-electronics industries. A bit less sexy, but no the less mind-boggling.
Article source: Wired