Formula One's Goldilocks Enigma

Goldilocks was hungry. She tasted the porridge from the first bowl.
"This porridge is too hot!" she exclaimed.
So, she tasted the porridge from the second bowl.
"This porridge is too cold," she said.
So, she tasted the last bowl of porridge.
"Ahhh, this porridge is just right," she said happily and she ate it all up.
(Goldilocks and the Three Bears)

Something curious is happening with the tyres in Formula One this year. At first sight, it appears that if you have too much downforce, then you'll put too much energy into the tyres, and they'll suffer thermal degradation. Conversely, if you have too little downforce, then the car will slide around and/or fail to warm its tyres sufficiently. If, however, your level of downforce is 'just right', then you'll be able to optimise your speed over a race distance. It might be suggested that teams such as Genii and Williams find themselves in exactly this zone of habitable downforce.

The truth, however, will be far more complex than this. For a start, teams such as McLaren appear to move in and out of the habitable zone depending on track temperature and car set-up. And it may be that Williams and Genii were smart enough to realise at an early stage the importance of working backwards from the characteristics of the Pirelli tyres to a specification of mechanical and aerodynamic requirements.

It was Peter Wright, I think, who pointed that, unlike aircraft, the control surfaces of a racing car are provided, not by the wings, but by the tyres. The ultimate logical development of this is not merely sophisticated, team-specific tyre modelling software, but simulation tools which integrate such tyre modelling with CFD.

Now more than ever, it is the interaction between the solid visco-elastic control surfaces, the forces generated by the viscous fluid flowing over the solid geometry of the car, and the transmission of those forces by visco-elastic spring-damper systems, which will become the key to extracting maximum performance.