Motorsport is the reason carbon fiber has made an entry into car manufacturing and the world of racing continues to innovate and promote new materials.
Take Porsche, for example, which has developed body parts made of renewable raw materials. The parts will be put to use on a Porsche 718 Cayman GT4 Clubsport MR race car that will enter this year’s Nürburgring 24-hour race with a complete body kit made of natural-fiber composite materials.
Since early 2019, Porsche manufactured the two doors and the rear wing of the racer out of a natural-fiber mix, sourced primarily from renewable raw materials. Now, for the first time, the front and rear aprons, the front spoiler, front and rear lids, as well as the mudguards and diffuser including the aerodynamic fins are also made from this regenerative material.
These renewable materials replace the metal and plastic injection moulded components of the production sports car, bringing several benefits along the way. In terms of weight and stiffness, the recyclable natural-fiber composite materials are similar to carbon-fiber composites (CFRP), while meeting the same high safety and quality standards.
The advantage over CFRP is that natural-fiber composites can be manufactured more economically and with less energy. Moreover, the damping of vibrations improves fivefold and, in the case of an accident, parts made from natural-fiber composites splinter into larger and less sharp pieces.
The project began in 2016 as a collaboration between Porsche, the Federal Ministry of Food and Agriculture (BMEL), the Fraunhofer WKI and the Swiss company Bcomp.
The base of the material is represented by farmed flax fibers, and Porsche says that doesn’t conflict with food crops. For the doors, light balsa wood serves as the core of the composite material, with the sandwich construction correlating to the well-known resin transfer moulding (RTM) process used in the production of carbon-fiber components.
By contrast, for the rear wing, layers are impregnated with epoxy resin, then baked in an autoclave. The components made of natural-fiber reinforced plastic are created using a vacuum infusion process and contain Bcomp’s proprietary powerRibs technology to fulfill stiffness requirements.