Coming Soon: Cars Made Of Wood?

 

(Opas Chotiphantawanon / Alamy)

Poor carbon fibre. What began as a late-20th Century wonder material for military aircraft was then nobly adopted by the motorsport world for strength, low weight and energy dissipation. Yet now, well into its career as a mission-critical material, it has also become window dressing in the aftermarket. Faux carbon fibre key fobs, shift knobs and dash appliques for '60s muscle cars are all generating real sales and real revenue.

Real carbon fibre, mind, is still just as wondrous as it was in the last century, even if a bit more commonplace in road cars. But it's still very expensive to make in large pieces and quantities, it requires copious energy to manufacture, can be very brittle if made poorly, is not recyclable and can impose a detrimental impact of the environment when being produced. In other words, it is ripe for disruption. Technology stands still for no one. But could nature provide carbon fibre's replacement?

Wheels of change

Lexus: Steering us to bamboo first?

As a purveyor of serene luxury cars, Toyota's Lexus division is one of a handful of carmakers  committing to renewable materials – albeit on a limited scale. Now offered on eight models, Lexus' bamboo-rimmed steering wheel shows the feasibility that Gary Young has espoused for years. Bamboo crops up elsewhere in the Lexus lineup, too. The CT200h uses the wood for the stereo's speaker diaphragms.
In designing the steering wheel, engineers Shuichi Ozaki and Yoshihiko Kanamori measured the grip pressure at various locations on the wheel by drivers. After identifying the highest pressure portions of the wheel, they sanded down those sections to yield as soothing a shape as possible. “When you’re comfortable at the wheel, you don’t feel as tired even after a long drive,” Ozaki says. “I designed this wheel to help give the driver a sense of security.” The type of bamboo Lexus uses take three to four years to mature, or about 10 times quicker than more commonly used woods, such as walnut.

So argues Gary Young, a renowned manufacturer of surfboards who has spent his life pioneering alternative materials use for that industry. "With the right approach, bamboo can be used in many applications in the automotive world where its performance qualities can better carbon fibre's,” Young says. “Plus, it does not have a negative effect on the environment."
The earliest surfboards from Hawaii were made from heavyweight koa wood. As the hobby gained a toehold in the mainland US, fibreglass ascended as the material of choice (as well as in boating), despite many downsides not considered in the 1950s and '60s, including its use of toxic resins and glassfibre dust, which is nasty to breathe.
Young had an epiphany while sitting in a queue for gasoline during the fuel crisis in 1973, when many reports circulated that the world's crude oil would soon dry up. "I though then that if we really are running out of oil, we should figure out how to use renewable materials," he says. Thus began his trip to bamboo.
Long years of research and development netted a formula of bamboo weave with an epoxy coating that worked, netting a very strong, light surfboard, yet it was not brittle. It is doubtful that bamboo could ever replicate the sheer strength and stiffness of a supercar's tub or suspension arms for a Formula 1 car, but carbon fibre is currently being used in many less-stressful applications.
Bamboo does, however, look promising on many levels. Using Gary Young's type of weave process with epoxy, the material could pass several traditionally difficult hurdles for new-car production. It could withstand flame and fire resistance standards, especially with an epoxy uniquely formulated to do so. It inherently absorbs hard impacts, an ability that could be deepened with proper engineering, all without the risk of shattering. (Indeed, Lexus is already trimming car cabins with bamboo; see sidebar). The wood costs pennies per pound and is perhaps the best possible renewable material, as it grows at a furious pace. Some species grow up to 100cm per day.
Additionally, the dust from bamboo weave production decomposes over time, unlike the dust from carbon fibre or other synthetic materials, which lives on in landfills.
The big questions centre on production techniques. Are they adaptable from a cottage industry such as surfboard production to a complex web of raw material, shipping, supplier manufacturing and, ultimately, the carmaker itself? And there is no bypassing some inconvenient truths about the raw material. For instance, bamboo has nodes at several points up the stalk, which makes larger-scale production and larger pieces difficult. This can be solved partly by sourcing woven bamboo (which also eliminates the nodes) that ships in sheets, but those sheets don’t ship in optimal sizes for automotive applications. Questions also surround the epoxy used in coating the bamboo weave, the stability of which is untested at the high temperatures common in automotive fabrication.
Which all leads to inconclusive evidence that bamboo will not replace carbon fibre. For now. Things could change. After all, at one time a farm-tractor builder named Ferruccio Lamborghini was a Ferrari customer.

The 2014 Fiat 500L Trekking ‘Street Surf’ show car used bamboo mirror caps. (Fiat USA, via Newspress)

Source:bbc.co.uk