Rooted wheels in McLaren's future

Frank Stephenson, McLaren Automotive Design Director, visited Melbourne last week for the opening of the brand's new dealership in Richmond.

Straight from another paying gig in Japan, Stephenson regaled local journalists with his farsighted vision of automotive technology and engineering likely to have an impact on the world of styling.

One of the first items he mentioned was wheel design that takes its cues from the root system of trees. As Stephenson pointed out, a tree's root system doesn't radiate out from the trunk in a consistent, regular way. Roots shoot out in all directions; they're not straight and true; sometimes they're not even located equally spaced around the trunk.

Stephenson explained how this could benefit vehicle design and engineering. It could absolve wheel design of the uniformity that has been a hallmark of the art since time immemorial. If it sounds a bit like the stylist getting ahead of himself for the sake of his own passion, Stephenson also says that this approach to wheel design could yield weight savings and additional strength.

"It's based off bio-mimicry," Stephenson explained to motoring.com.au. "You don't have symmetrical spokes...

"The reason why we're looking at it is because wheels are unsprung weight. So if you make a heavy wheel, you notice it when you're driving."

Stephenson cited the Californian Sequoia as a tree that grows very high, but has a shallow root system that spreads wide to keep the tall trees stable. The McLaren designer posited the tree as a model for wheel design, with the (sawn-off) trunk as the hub and the (simplified pattern of) roots as spokes.

"What you do is you get very curvy or very bent spokes. And what that allows you to do is when the wheel gets hit, instead of the impact going straight to the centre of the wheel, it dissipates much sooner. So you can make the spokes a lot lighter, a lot thinner. Then, what you need to do is counter-balance the wheel, obviously, but you can do that behind the spokes.

"So what you have is a wheel with all different-size-looking holes in the wheel. They're very unusual looking; it's a lot lighter, a lot stronger..."

The aim of this type of design, Stephenson explained, is as much about imbuing an unusual, naturally unbalanced and complex look to the wheel, without conceding strength or lightness. If anything, wheels designed along these lines (so to speak) would reduce unsprung mass considerably more than current engineering conventions.

But the wheel design doesn't have to be locked into the root-system paradigm for optimal weight and strength. It does lend the wheel a different aesthetic, however, which is why the idea has caught Stephenson's attention.

"Every spoke is different. You could do it the same if you wanted... It just allows you to free up the design and do something a lot different.

"Wheels will look extremely different from today, but they're also going to be stronger and lighter."

The McLaren stylist also said that the future could or would bring thinner roof pillars, as car companies embraced carbon-fibre construction to a higher degree.

"Currently, today, most canopies are made out of alloys, but if you could run carbon up there – carbon is so much stronger and stiffer than steel – suddenly you're making canopies with carbon structures that allow you to do a lot thinner [roof pillars] than ever before."

Stephenson didn't see any prospect of technology transfer from F1's current fascination with head protection to McLaren's road cars.

"The only reason they're doing that is for possible impacts because their head's sticking outside the car. But our main concern is rollover conditions, not things coming at you."

And this led Stephenson to reveal another eye-opener. Cars of the future may do without a headrail for the roof.

"You can get away without a header on the car. You just have the A pillars coming up, going towards the back; in a carbon designed environment, that is sufficient for a rollover. You can basically get rid of the header bar that restricts your vision...

"We haven't done it yet, but we could minimise it to such a point that you really don't even need it. The reason why most companies use it is to connect the sunvisors. But then you can get rid of the sunvisors, because sunvisors are crazy too..."

According to Stephenson, windscreens can use photo-optics to tint automatically and do away with sunvisors. The rear-view mirror can be replaced by something like a smartphone turned on its side for a landscape image, taking a feed from a rear-mounted camera.

Other 'technology' that has outlived its usefulness, according to Stephenson, is the humble windscreen wiper, which he described as "one of the oldest bastions of bad design on a car". As he explained, jet fighters don't use them, why should high-performance cars?

By running an electric current through a conductive windscreen and setting up a vibration, the windscreen can divest itself of rain drops and even frost (with the added assistance of a heating element in the glass). It saves weight by doing away with the heavy and inefficient wipers, plus water bottles and pumps for the washers. Plus there are aerodynamic efficiency gains.

Stephenson is a man with a mind that's obviously looking at any new technology for its possible application to the automotive industry. McLaren is even considering technology that would allow the customer to change the colour of the car every day, should he or she wish.

As Stephenson pointed out, this is not technology decades away from introduction to mainstream vehicle production. Expect to see these ideas on a production car within the next few years.

Picture of Sequoia root system courtesy of Giorgio Galeotti/Wikimedia Commons