Hot tubs

Carbon fibre monocoques lie at the heart of most top-level racecars, and they’re a complex piece of engineering in their own right. Racecar investigates

- Lawrence Butcher

Under the skin of any modern racecar, at least of the Sports Prototype or formula variety, is the tub, or monocoque. A multi-functional component that must fulfil many design requirements, some of which are diametrically opposed.

Its primary role is to fill the void between the front suspension and the engine, providing sufficient structural stiffness for said suspension to operate correctly. At the same time, it must safely house the driver (to varying degrees of comfort, depending on the application), the fuel cell and, as is increasingly the case, an energy storage system (ESS) for either an electric or hybrid drivetrain.

Additionally, the tub must be as light as possible, while also having as minimal effect on the overall footprint of the car as is feasible. Aero is a predominant concern and, as such, the monocoque, just as with the powertrain, cooling system and any other ancillary components, plays second fiddle to aerodynamicists’ desires when it comes to real estate.

Think of the shape of a modern Formula 1 tub. It is not through choice that the driver sits with their legs up in the air, with the chassis cut away sharply below. The form is driven by the need to channel as much air as possible under the nose of the car.

All of these competing demands need to be balanced out. Ultimately there will be compromises, but with contemporary design, simulation, manufacturing methods and materials, they can be reduced.