01

02

03

Lexus is improving vehicle performance by adopting a once-unusable
manufacturing material. shogo hagiwara explains how
Until recently, carbon was considered a second-rate material when it came to manufacturing cars. Benefits lay in its weight – it’s light and flexible – but the substance lacked strength in comparison with steel and aluminum, and it was prone to breaking under pressure. Recent technological advances have turned that widely held view on its head.
Carbon is still light, but it is now also sturdy, rigid and reliable under intense pressure. So much so that Lexus has begun to use the material in a variety of applications, notably in a comprehensive package of carbon fiber parts fitted to the brand’s new coupe, the RC F. Here we explore the parts (the engine hood, the roof and the rear spoiler), the material from which they’re made, and the technology that has enabled them.

The Benefits

Each part of the carbon package – the engine hood 01, the roof 02 and the rear spoiler 03 – makes a huge difference in vehicle performance. Using carbon in exterior body panels lowers the car’s total weight, which in turn lowers its center of gravity. That means tires can better grip a road’s surface, especially when cornering, making it resistant to sideways g-force.

Carbon makes a difference on the inside, too: chassis and cabin sections formed of the material can increase a vehicle’s rigidity. That’s why Lexus engineers opted to use carbon to construct the body frame of the LFA, the brand’s two-seater supercar, and why they’ve extended use of the material here, in the RC F package.

THE WEAVE

The surfaces of the carbon package elements feature intricate patterns formed when a multitude of carbon fibers are woven together diagonally – a pattern typical of carbon parts (see detail) – giving the RC F a sharp and sporty appearance. Examine a unit of carbon under a microscope and you’ll find the material to be an extremely fine acrylic fiber measuring only several micrometers (a unit of length equal to one thousandth of a millimeter) in diameter. Depending on the strength of the material required, anywhere between 3,000 and 24,000 of these fine threads are bundled together to form a tow, and numerous tows are woven into a carbon fabric, similar to a yarn.

HOW THE PARTS ARE MADE

The engine hood 01 and the roof 02 are formed from four 0.5-millimeter-thick carbon sheets machine-pressed together at 140 degrees Celsius. The rear spoiler 03 consists of two different materials, carbon and fiberglass, and becomes beneficial when the car exceeds 50mph. At this speed the spoiler automatically extends upwards, giving the wheels more traction on the road. It may be extended manually at any speed. “Technological advances have made carbon less

expensive to purchase than before,” says Ryoichi Ishikawa, project manager of the Lexus Sports Vehicle Management Division. “But it’s still expensive, and we can only use it for vehicles in the upper echelons of the lineup. Our ultimate goal is to further develop our technology to make carbon parts inexpensive enough to use in entry models. In my view, carbon, which is now five to six times stronger than steel, is a material of the future.”

01
02
03

01

+

02

+

03

+
TEXT BY SHOGO HAGIWARA
PHOTOGRAPHY BY MIKIO HASUI
repeat