‘Yes, but where are the hoverboards?’ That has been a common refrain from frustrated gadget lovers as the technological advances piled up in the years since the release of Back to the Future II in 1989.
As we all know, our protagonist Marty McFly ventured forward in time in the second instalment of the Back to the Future franchise to 21 October, 2015, and got his hands on a hoverboard, which went on to play a rather important role in the film.
It is here: The Hendo hoverboard
Now, in an amazing feat of both engineering and marketing, Californian Company Arx Pax has announced it is about to win the pop culture version of the Space Race by producing hoverboards that will be ready for shipping on 21 October, 2015.
A Kickstarter campaign has been launched for the Hendo board and already $207,485 has been raised towards the $250,000 goal. There were 10 working Hendo boards available for pledges of $10,000 or more and these have already been claimed.
Wow: Marty McFly discovers the hover board in Back to the Future II
When McFly tries to ride the board over water and fails, Data famously calls out, ‘Hey McFly, you bojo, those boards don’t work on water!’ It is a similar case with the Hendo, as it can only hover over non-ferromagnetic metals like copper, silver or aluminium.
Arx Pax is light on the details of the Magnetic Field Architecture technology, but the hoverboard’s four battery-powered disc-shaped magnets on its lower surface suggest it is floated through electrodynamic suspension.
The Kickstarter page mentions the designers developed a keen understanding of both Earnshaw’s Theorem and Lenz’ Law in order to develop the board.
While Earnshaw’s Theorem states you can’t simply float a magnet above another magnet without physical stabilisation, this can be overcome by switching the polarity of an electromagnet through the expenditure of energy.
Once the board is moving, Lenz’s Law explains another method of stabilisation through ‘eddy currents’. It says that these eddy currents create a magnetic field that oppose the magnetic field that created it. The law is effectively an explanation of Newton’s third law of the conservation of energy for magnetism – that for every action there is a reaction.
There are other ways to float things through magnetism, as we have seen a frog suspended through diamagnetic levitation in the past, and superconductors have been floating extremely cold objects for years.
So the hoverboard dream may soon be a reality, but only in specially-built parks and for those that have a lot of money to spare.
Where Arx Pax will most likely make its money is through selling its levitation technology to industry, rather than by mass-producing hoverboards.
James Perkins is News Editor of Materials World