CFRP seats and interior: Sitting pretty
When Automobili Lamborghini SpA (Sant’Agata Bolognese, Italy) premiered its new Aventador J roadster at this year’s Geneva Motor Show (March 8-10), the automaker had a few surprises in store for its audience. Judging from the buzz the vehicle earned at the show — more than 21.5 million Google searches; hundreds of thousands of hits on a handful of YouTube videos; 6,800 tweets (potentially reaching 40 million viewers); and a new daily-traffic record on the automaker’s Web site — car aficionados were pretty excited by what they saw.
Loosely based on the Aventador LP 700-4 coupé (launched in 2011, see “Automotive CFRP ....,” under "Editor's Pics," at top right), Lamborghini describes the new 12-cylinder, 6.5-liter, 700-hp two seater as “radically open,” because the roof, pillars and front windshield have been eliminated and only two small wind deflectors provide some protection for occupants’ faces, much like windscreens on superbikes. This isn’t a docile convertible whose top can be pulled up at a hint of rain; it’s a permanently open cockpit designed for an “extreme driving experience” where driver and intrepid passenger really experience the full-sensory impact of rocketing down track or road at 300 kmh (186 mph). The automaker cautions that before attaining such speeds, occupants must wear the right equipment — likely five-point safety harnesses and helmets with eye protection.
What’s even more amazing is that this vehicle was designed and built in just six weeks, yet it’s a fully functional, properly homologated, street-legal supercar. Although it shares its engine and powertrain and a few body components (hood, fenders and headlights) with the Aventador coupé, almost everything else on this roadster is bespoke, designed just for the Geneva Motor Show. Yet, like the LP 700-4, the new J model is a technology showcase for innovative uses of carbon fiber-reinforced polymers (CFRP), many of which the automaker has pioneered during the past three decades. CFRP parts are visibly evident throughout the vehicle interior and exterior, most of them clearcoated to show off the weave of the carbon fabric.
The car makes use of carbon fiber composites on the front air scoop, which features central fixing braces and upward-tilting winglets on the outer edges, and on the rear diffuser, which is connected to an enormous composite spoiler. Each wheel sports a five-bladed CFRP fan to cool the brakes. Under the rear diffuser sits a bonnet, a black metal mesh for heat dissipation and a tubular engine frame, also made of carbon composites.
Additionally, the J model sports special front and rear bumpers that make use of CFRP fins, which act as airflow deviators to increase downforce for better handling at high speeds — effectively taking over the role of dive planes (canards) and the front splitter. Like the LP 700-4 coupé, the new roadster features a CFRP-intensive monocoque that is very light and stiff and provides Formula 1-type passenger protection; but, minus the A- and B-pillars and roof, the car is equipped with two CFRP safety roll bars behind the seats. In fact, the company says the outer chassis has been completely redesigned for the J model.
Inside, the Aventador roadster makes use of carbon fiber composites in its unique seats, each of which is a two-piece bonded shell structure featuring Forged Composite, a material codeveloped through a strategic partnership between the R&D groups at Lamborghini and Callaway Golf Co. (Carlsbad, Calif.) and first shown on the monocoque and suspension arms of Lamborghini’s Sesto Elemento demonstrator vehicle at the 2010 Paris Motor Show. Forged Composite is said to be the lightest, strongest and most precise material that either company has ever used. It features more than 500,000 intertwined, randomly oriented turbostratic (that is, high-tensile-strength, polyacrylonitrile-based) fibers per square inch and makes precision parts capable of withstanding extremely high forces. The parts are molded by means of a proprietary, out-of-autoclave, isothermal forging process, which Lamborghini says offers unprecedented levels of quality and cost reduction. The result, says the company, is a seat set that is 30 percent lighter than traditional sports car seats. Further, the material is stronger than metals. At one-third the density of titanium, Forged Composite possesses greater load-carrying capacity per unit of mass during bending and is better able to withstand long-term aging and environmental effects.
Not least, a completely new carbon composite material is used for the first time as upholstery/trim on the seats. Called CarbonSkin, this innovative, flexible carbon composite was developed and patented by Lamborghini and is produced for the automaker by a partner company. CarbonSkin is cobonded and sewn to the front of each Forged Composite seat shell after molding. It adorns other cockpit surfaces as well, including the door panel inners, the instrument panel topper pad and the center console.
Reportedly, the material is made of woven carbon fibers (in a 2x2 twill pattern) that have been soaked in a specially formulated resin. Described as an “entirely new impregnation system” not previously used in the market, the resin stabilizes the fiber structure after it is cured, yielding a composite that remains strong yet soft and flexible. Although it is not breathable in its current format, the resulting matte fabric is said to have excellent drape and hand (a soft feel to the touch) and conforms to a wide variety of contours.
Asked about the future of this new material, Luciano De Oto, chief of the Lamborghini Advanced Composite Research Center (ACRC), says, “You can imagine all the uses in applications that require flexible, light and strong materials,” noting that beyond auto trim upholstery, other possible uses include high-end clothing and luggage. De Oto also says the new CarbonSkin fabrics have passed Lamborghini’s wear and aging tests and actually contribute to absorbing deformations made by a seat occupant’s back and head. “For sure, this material is a step forward in the standard conception of automotive interiors,” he adds.
For those who are already adding the Aventador J to their Christmas wish list, the biggest surprise of all is that Lambor-ghini has made only one of them — there are no prototypes and no set-aside versions for the Lamborghini Museum. The unnamed but well-heeled buyer who purchased this “production run of one” before the Geneva Motor Show reportedly plunked down €2.1 million ($2.76 million USD) to own “a truly unique, street-legal work of art.” To console the brokenhearted, the automaker does say that “the Aventador success story has only just begun.” Presumably, the unique features of this supercar will return on new models yet to come.
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