The Mclaren Formula 1 team has collaborated with Swiss company Bcomp to develop a natural fibre racing seat for Carlos Sainz and Lando Norris – the very first F1 car part to be made of renewable textile fibres. By optimising the mechanical properties of flax fibres through fabric architecture, it’s been possible to create a seat with the required strength and stiffness, but with a 75% lower CO2 footprint compared to its carbon fibre counterpart.
Primarily used in the production of linen, flax is an incredibly versatile plant that has been around for millions of years. It differs from many biomaterials in that it’s ideal for use in crop rotation programmes and can be grown without directly competing with food crops. Flax is a CO2-neutral raw material and its fibres are biodegradable. At the end of the seat’s life, for example, it can be ground down into a new base material or thermally recycled without residual waste, rather than end up in landfill.
Inspired by the thin veins on the back of leaves, Bcomp’s powerRibs technology provides a three-dimensional grid structure on one side of the seat, which is then used to reinforce the spun and woven flax fibre reinforcement fabric, ampliTex. Made by twisting flax fibres to form a thick yarn, the powerRibs act as a backbone to the ampliTex flax fabric that is bonded to it
With the introduction of the new regulation in 2019, the seat now forms part of the driver’s weight budget, so it’s over-engineered as a result
McLaren saw a clear opportunity to use this technology in this area of the car based on the current F1 technical regulations. Since 2019, a minimum driver weight of 80 kg has been mandated. And if a driver weighs less than that, ballast must be used to bring them up to the minimum weight. But instead of allowing this ballast to be placed in other areas of the car, which could improve weight distribution, it must be located within the immediate area of the driver’s seat.
While the environmental benefits are clear, the mechanical properties of flax make it an attractive renewable raw material for high-performance composites. The tubular structure of flax fibres provides low density and high stiffness, which affords the opportunity to reduce weight while simultaneously improving vibration damping, as well as resistance to breakage, torsion and compression.
Flax fibres are 9% lighter than any equivalent carbon material and offer significantly better vibration damping.
Greater vibration absorption and impact resistance make the natural fibre material well suited to use in the driver’s seat. It improves comfort and reduces vibration in the cockpit, which can have a fatiguing effect on drivers and if the seat were to break, unlike carbon fibre, it’s not prone to brittle fracture and splintering.
The ductile fracture behaviour of natural fibre composites opens the door to other possibilities too. One of the most spectacular, but equally dangerous, aspects of an on-track incident is the shards of carbon fibre that result from a collision. Not only do they present an immediate risk to the drivers, but they are also notorious for causing punctures and leaving a driver’s race in tatters. By using natural fibre composites in other areas of the car, such as front wing endplates and the floor, it’s possible to reduce carbon fibre debris and therefore the risk of punctures.
The cost of materials is going to be a big focus and the use of natural fibre composites has the potential to help in this area
With a budget cap set be introduced from 2021, many F1 teams will need to reduce costs while maintaining and improving performance – no mean feat in a sport where, typically, a team can pursue more development routes the more resource it has available. Teams are going to have to work even smarter, McLaren says that using these natural composite solutions has seen a reduction in raw material cost by up to 30% compared to traditional carbon fibre.
Most of the moulds used to make parts of the car are made from carbon fibre composite because of its low thermal expansion. However, flax fibres also possess this property, potentially making them a suitable tooling material for moulding performance parts that are made from standard composites. So even if the part being produced isn’t made from natural fibre materials, the tool to produce it can be – allowing us to reduce the cost of mould tools and our carbon footprint.
With so many potential applications, McLaren sees the natural fibre racing seat as just the beginning and will continue to work with Bcomp to identify other components that can be replaced. The seat was run in pre-season testing without any problems and McLaren hope to be racing with the Bcomp flax seats in the near future.