Critical Thinking – what can carbon fibre teach us?

Maclaren racing car winning the 1981 Grand Prix

In 1979 racing car designer John Barnard was exploring the use of carbon fibre as a material for making Formula 1 cars and critical thinking was key to this research. His interest was in making the chassis narrower and lighter, without any loss in strength or torsional stiffness (the ability to withstand twisting.)

Barnard approached British Aerospace, who were working with this new product, and asked for their help. Arthur Webb, an aeronautical engineer and carbon fibre (and carbon fibre composite) expert, came on board (in his spare time!) Together Barnard and Webb changed motor sport history. What they did was to think about this new product differently to the way other people were approaching it.

Lesson 1 – Barnard realized that their competitors were trying to use carbon fibre in the same way as they had been using metal. However, aluminium is “stretchy” whereas carbon fibre is brittle. Both products would behave very differently under stress and in an accident.

Critical thinking lesson 1 – techniques that work in one situation don’t necessarily work in another, even if the materials look the same.

Lesson 2 – Hercules Aerospace, an American firm, were funding the construction of the new chassis. Their technicians calculated that the design that Barnard and Webb had come up with wouldn’t work. However, in their calculations they had treated the carbon fibre as “black metal”. Arthur Webb was able to convince them that their calculations were based on wrong assumptions.

Critical thinking lesson 2 – challenge the assumptions you and others are making.

Lesson 3 – Concerns were raised by competitors and in the sporting press, that this new material was dangerous and wouldn’t protect the driver in a crash. Their main objection was that carbon fibre was brittle. What they didn’t take into account was

    1. that brittle in engineering terms has a different meaning to what the man in the street means by brittle.
    2. the carbon fibre composite material has fibres running in many directions to give it all round strength and is sandwiched around a honeycomb of aluminium.
    3. carbon fibre maintains its strength right up to the point where it breaks, unlike metal, which loses its strength as stress is increased.

Critical thinking lesson 3 – check that everyone understands something in the same way.

Maclaren racing car winning the 1981 Grand Prix
What a car! A win for carbon fibre.

And Finally

Their new car, driven by John Watson, won the British Grand Prix for Maclaren in July 1981. Later that year, Watson crashed his car at the Italian Grand Prix. Webb and Barnard had built into the design weak points where the chassis would break, giving them a safety advantage. The engine mounts broke, so that the engine sheared away from the rest of the car, reducing the kinetic energy and putting distance between the driver and engine. Watson walked away unharmed and concerns about this new product faded.