© McLaren.

Specialists from McLaren and Bcomp explain the development and advantages of Formula One motor racing’s first natural fibre composite racing seat.

Since the inaugural round of the FIA Formula One World Championship in 1950, the motorsport has pushed the boundaries of technology in pursuit of performance, making it the birthplace for countless ingenious innovations.

Among them was the introduction of the first car with a carbon fibre monocoque chassis, the MP4/1, introduced by McLaren at the start of the 1980s. Light, strong and a huge leap forward for safety, it has heavily influenced racing car design to this day.

Now McLaren, headquarted in Woking, UK,  and Bcomp, of Fribourg, Switzerland,  have optimised the mechanical properties of flax fibres through fabric architecture, achieving a seat with the required strength and stiffness, but with a 75% lower CO2 footprint compared to its carbon fibre counterpart.

“The use of natural fibre composites is the latest example of pioneering, composite materials innovation at McLaren,” said McLaren F1 Team Principal Andreas Seidl. “Not only does this solution provide equivalent performance to carbon fibre, it represents another step forward in our evolving sustainability programme.”

© McLaren.

Evolution

“For decades, F1 has been an innovation lab for technology that has transformed not just motorsport, but the automotive industry and beyond,” added McLaren F1 Technical Director James Key. “The sport must continue down the road of getting to an increasingly environmentally friendly set of conditions, and our development and application of natural fibre composites is an example of how we’re accelerating this journey, as well as the ongoing evolution towards cleaner mobility.”

For Bcomp CEO and co-founder Christian Fischer, sustainability and decarbonisation is a global issue and he welcomes motorsport embracing carbon alternatives, paving the way for widespread adoption within large-scale mobility applications.

“McLaren has always been a pioneer within the sport, in terms of both composites and sustainability,” he said.

Flax advantages

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 McLaren 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 proprietary powerRibs technology provides a three-dimensional grid structure on one side of the seat, which is then used to reinforce Bcomp’s optimally 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.

© McLaren.

Ballast

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. 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.

“With the introduction of the new regulation in 2019, the seat now forms part of the driver’s weight budget, so it’s overengineered as a result,” explained McLaren F1 Principal Composites Engineer Steve Foster.

The first flax composites seat has been test driven by McLaren Racing Team drivers Carlos Sainz and Lando Norris.

“With Carlos and Lando weighing in at 72 kg and 68 kg respectively, there was margin to use additional bio-composite material to ensure sufficient strength and stiffness in this safety-critical component,” said Foster. “The original carbon fibre seat design was reverse-engineered by Bcomp and then we optimised and manufactured the new design. The seat was run in pre-season testing without any problems and we hope to be racing with Bcomp flax seats in the near future.

“We believe this seat functions as a conclusive demonstration that our technologies are ready to compete in the top tier of motorsport,” added Fischer. “We match conventional carbon fibre while lowering the eco footprint by 75%, cutting costs, reducing vibrations and improving safety – all of which are highly relevant to achieving a sustainable future for motorsport and mobility.”

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.

© McLaren.

Vibration damping

Flax fibres are 9% lighter than any equivalent carbon material and offer significantly better vibration damping.

Thanks to Bcomp’s ampliTex flax fabric and powerRibs technology, the greater vibration absorption and impact resistance makes 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, especially over a race distance and particularly at circuits with aggressive kerbs.

When it does break, unlike carbon fibre, it’s not prone to brittle fracture and splintering – a property that’s enhanced further by the structure of Bcomp’s powerRibs which stiffen and confine the damage zone.

“The composite of ampliTex and powerRibs is not as fragile, and while it still breaks, the softer debris remains attached to the main structure with the help of the powerRibs, which help dissipate the energy,” explained Fischer.

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 are the shards of carbon fibre that result from a collision. Not only do they present an immediate risk to the drivers, they are 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.

Reducing costs

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, and with Bcomp’s ampliTex and powerRibs solutions reducing raw material cost by up to 30% compared to traditional carbon fibre, this significant saving can free up budget to explore other ways of improving car performance.

“With the introduction of the budget cap, 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,” said Key. “We’re working with Bcomp to confirm that natural fibre composites are a viable, sustainable and economical substitute for carbon fibre in some applications, both on and off the car.

“Looking outside the sport to find new technologies is a crucial driver of innovation that can deliver unique competitive advantages. Through the experience gained this season, we’ll have learnt more about sustainable composite materials and the potential for their application in the future.”

“Where we see significant potential is in the non-critical, semi-structural areas of the car, such as the driver’s seat, as well as off the car,” added Fischer. “When used intelligently, the flax fibres reduce weight and cost, while maintaining and, in some cases, even improving performance. There are a range of possible applications beyond the car itself, including pit gear, truck panels, packing cases, timing stands and mould tools.”

Currently, most of the moulds used to make parts of the car, for example, are made of carbon fibre composite because it has low thermal expansion. Flax fibres, however, 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 McLaren  to reduce the cost of mould tools and its carbon footprint.

First step

With so many potential applications, the natural fibre composite racing seat is just the beginning.

“This seat is the first step in the successful application of natural fibre composites in F1,” Seidl concluded. “By working with Bcomp we can identify other components that we can replace with a sustainable alternative that has equivalent weight and performance. There is no silver bullet in the race to be carbon neutral. Instead, we must continually evaluate every element of our cars and our operations to identify the ways we can improve performance, drive efficiency and reduce environmental impact.”

https://www.bcomp.ch/