This is why @Google X wants to build a hoverboard. by @chrisgayomali via @FastCompany

This Is Why We Don't Have Google X Hoverboards Yet

Yes, Google X tried to design a hoverboard.

If Back to the Future has taught us anything, it's that hoverboards are amazing, and it is one of 2014's inexcusable tragedies that they are not yet real.

Which isn't to say that some very smart people haven't tried to build them. In this month's inside look at Google X, Google's fantastical R&D lab, researcher (and avid skateboarder) Rich DeVaul says he tried to design one. Why? "I just wanted one," he says.

Things started off promising enough:

In front of him is a small, shiny rectangle, about the size of a hardcover book. On the surface is a tight configuration of circular magnets. "So the first question here relates to the physics," [researcher Dan Piponi] says. "Can you actually have an object hovering about? And so people try really hard with magnets—to find some arrangement that keeps something hovering."

Magnetic levitation isn't new. In fact, superfast trains in China and Japan use similar technology to eliminate friction, reaching speeds up to 361 mph. The downside, though, is that this rail system wouldn't work quite as well with something like a hoverboard, which, in theory, would need to be omnidirectional to have any value:

These "mag-lev" systems have a stabilizing structure that keeps trains in place as they hover and move forward in only one direction. That couldn't quite translate into an open floor plan of magnets that keep a hoverboard steadily aloft and free to move in any direction. One problem, as Piponi explains, is that magnets tend to keep shifting polarities, so your hoverboard would constantly flip over as you floated around moving from a state of repulsion to attraction with the magnets. Any skateboarder could tell you what that means: Your hoverboard would suck.

That said, a functional hoverboard has tremendous value beyond skater dudes kick-flipping over buildings. Frictionless hover technology could have practical applications in a number of industries—from transportation to supply chain logistics. "Imagine a giant fulfillment center like Amazon's, where all the pallets can levitate and move around," DeVaul says. "Or what about a lab where all the heavy equipment would come to me?"

So the Google Xers pressed on:

There are loopholes in this theorem that you have to find," Piponi says. "There are materials that are kind of weird, that don't behave like magnets normally do." Piponi discovered that a very thin slice of a certain type of graphite would actually work well on a small bed of magnets. So he built one for the Rapid Eval team. He pushes his small hoverboard across the table to me, and I try it. The graphite slice, not much larger than a quarter, floats slightly above the magnets, gliding in any direction with the most ethereal push. When DeVaul first saw this, he tells me, he was astounded.

So why don't we have hoverboards yet?

As he did the calculations involved in expanding the small hoverboard up to a usable size, the physics suggested that at a certain point the weight of the board would knock it off its cushion of air. Other technologies could conceivably help (you might try using special materials at supercool temperatures), but the team ­decided that would create huge additional costs and complications—costs that would not be justified by the project's relatively modest social and economic impact. So the Google X hoverboard was shelved.

Read the rest of our Google X feature here.