A modern Formula One car has almost as much in common with a jet fighter as it does with an ordinary road car. Aerodynamics have become key to success in the sport and teams spend tens of millions of dollars on research and development in the field each year.
The aerodynamic designer has two primary concerns: the creation of downforce, to help push the car's tyres onto the track and improve cornering forces; and minimising the drag that gets caused by turbulence and acts to slow the car down.
Several teams started to experiment with the now familiar wings in the late 1960s. Race car wings operate on exactly the same principle as aircraft wings, only in reverse. Air flows at different speeds over the two sides of the wing (by having to travel different distances over its contours) and this creates a difference in pressure, a physical rule known as Bernoulli's Principle. As this pressure tries to balance, the wing tries to move in the direction of the low pressure. Planes use their wings to create lift, race cars use theirs to create downforce. A modern Formula One car is capable of developing 3.5 g lateral cornering force (three and a half times its own weight) thanks to aerodynamic downforce. That means that, theoretically, at high speeds they could drive upside down.
Early experiments with movable wings and high mountings led to some spectacular accidents, and for the 1970 season regulations were introduced to limit the size and location of wings. Evolved over time, those rules still hold largely true today.
By the mid 1970s 'ground effect' downforce had been discovered. Lotus engineers found out that the entire car could be made to act like a wing by the creation of a giant wing on its underside which would help to suck it to the road. The ultimate example of this thinking was the Brabham BT46B, designed by Gordon Murray, which actually used a cooling fan to extract air from the skirted area under the car, creating enormous downforce. After technical challenges from other teams it was withdrawn after a single race. And rule changes followed to limit the benefits of 'ground effects' - firstly a ban on the skirts used to contain the low pressure area, later a requirement for a 'stepped floor'.
Despite the full-sized wind tunnels and vast computing power used by the aerodynamic departments of most teams, the fundamental principles of Formula One aerodynamics still apply: to create the maximum amount of downforce for the minimal amount of drag. The primary wings mounted front and rear are fitted with different profiles depending on the downforce requirements of a particular track. Tight, slow circuits like Monaco require very aggressive wing profiles - you will see that cars run two separate 'blades' of 'elements' on the rear wings (two is the maximum permitted). In contrast, high-speed circuits like Monza see the cars stripped of as much wing as possible, to reduce drag and increase speed on the long straights.
Every single surface of a modern Formula One car, from the shape of the suspension links to that of the driver's helmet - has its aerodynamic effects considered. Disrupted air, where the flow 'separates' from the body, creates turbulence which creates drag - which slows the car down. Look at a recent car and you will see that almost as much effort has been spent reducing drag as increasing downforce - from the vertical end-plates fitted to wings to prevent vortices forming to the diffuser plates mounted low at the back, which help to re-equalise pressure of the faster-flowing air that has passed under the car and would otherwise create a low-pressure 'balloon' dragging at the back. Despite this, designers can't make their cars too 'slippery', as a good supply of airflow has to be ensured to help dissipate the vast amounts of heat produced by a modern Formula One engine.
In recent years most Formula One teams have tried to emulate Ferrari's 'narrow waist' design, where the rear of the car is made as narrow and low as possible. This reduces drag and maximises the amount of air available to the rear wing. The 'barge boards' fitted to the sides of cars also helped to shape the flow of the air and minimise the amount of turbulence.
Revised regulations introduced in 2005 forced the aerodynamicists to be even more ingenious. In a bid to cut speeds, the FIA robbed the cars of a chunk of downforce by raising the front wing, bringing the rear wing forward and modifying the rear diffuser profile. The designers quickly clawed back much of the loss, with a variety of intricate and novel solutions such as the ‘horn’ winglets first seen on the McLaren MP4-20.
Most of those innovations have been effectively outlawed under the even more stringent aerodynamic regulations imposed by the FIA for 2009. The changes are designed to promote overtaking by making it easier for a car to closely follow another. The new rules take the cars into another new era, with lower and wider front wings, taller and narrower rear wings, and generally much ‘cleaner’ bodywork. Perhaps the most interesting change, however, is the introduction of ‘moveable aerodynamics’, with the driver now able to make limited adjustments to the front wing from the cockpit during a race.
All this will make the cars slower initially, but as ever Formula One’s best brains will be working flat out to make up the performance shortfall as quickly as possible.