The Christmas Gift So Hot, It Sometimes Bursts into Flames
Wednesday, December 30th, 2015December 30, 2015
Did you or someone you know get a “hoverboard” for the holidays? Although they don’t actually hover, these devices allow users to glide along on two wheels with ease, performing sharp turns and quick stops, and cruising at over 10 miles (15 kilometers) per hour. Their popular name (and possibly the inspiration for the devices themselves) may come from Robert Zemeckis’s 1990 film Back to the Future Part II. In the film, which is set mostly in the year 2015, protagonist Marty McFly zooms around on a device resembling a floating skateboard. Although personal transportation technology hasn’t quite reached the level predicted in the movie, “hoverboard” users today can feel as cool as McFly as they cruise their neighborhood.
Despite (or because of) their novelty, there has been some backlash against “hoverboards” in recent months. They have been banned from streets and sidewalks in some municipalities and countries. Many airlines refuse to allow them on their planes. One of the reasons for the bans is that some cheaper models have been reported to burst into flames, probably because of poorly constructed lithium-ion batteries. Government agencies are looking into the safety of such devices, for fire risk as well as for their tendency to buck riders and cause injuries when they do not work properly.
Although these “hoverboards” do not actually hover, inventors have already created some prototypes that do. Some use supercooled magnets to generate a magnetic field, causing the board to float. These hoverboards must be used on special metallic surfaces in order to function, however. Other designs use fans to create a cushion of air on which the board floats. These designs can be used over any terrain, but their fast-spinning blades could be extremely dangerous to the rider and bystanders in the case of an accident.
At some level, both kinds of true hoverboards suffer from the same problem that many of the cheaper “hoverboard” brands have: poor batteries. The magnets of magnetic-field-based hoverboards must be extremely cold, so current prototypes require constant replenishment of liquid nitrogen or powerful refrigeration units. Fans require large amounts of energy to hold up a person. Therefore, both types can only float for a few minutes before they need to be recharged. Simply adding more batteries doesn’t improve their range, either: additional batteries make a board heavier, so it needs more fans or magnets to stay afloat. These devices then use more energy, requiring still more batteries. Only improvements in motor and battery efficiency may allow us to one day really hover along like Marty McFly.
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