A Modern Formula One Car Has Almost As Much in Common with a Jet Fighter As It Does With

AERODYNAMICS

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 After technical challenges from other teams it was withdrawn after a single race.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 were effectively outlawed under even more stringent aero regulations imposed by the FIA for 2009. The changes were designed to promote overtaking by making it easier for a car to closely follow another. The new rules took 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, was the introduction of ‘moveable aerodynamics’, with the driver able to make limited adjustments to the front wing from the cockpit during a race.

BRAKES

When it comes to the business of slowing down, Formula One cars are surprisingly closely related to their road-going cousins. Indeed as ABS anti-skid systems have been banned from Formula One racing, most modern road cars can lay claim to having considerably cleverer retardation.

The principle of braking is simple: slowing an object by removing kinetic energy from it. Formula One cars have disc brakes (like most road-cars) with rotating discs (attached to the wheels) being squeezed between two brake pads by the action of a hydraulic calliper. This turns a car's momentum into large amounts of heat and light - note the way Formula One brake discs glow yellow hot.

In the same way that too much power applied through a wheel will cause it to spin, too much braking will cause it to lock as the brakes overpower the available levels of grip from the tyre. Formula One previously allowed anti-skid braking systems (which would reduce the brake pressure to allow the wheel to turn again and then continue to slow it at the maximum possible rate) but these were banned in the 1990s. Braking therefore remains one of the sternest tests of a Formula One driver's skill. The technical regulations also require that each car has a twin-circuit hydraulic braking system with two separate reservoirs for the front and rear wheels. This ensures that, even in the event of one complete circuit failure, braking should still be available through the second circuit. The amount of braking power going to the front and rear circuits can be 'biased' by a control in the cockpit, allowing a driver to stabilise handling or take account of falling fuel load. Under normal operation about 60 percent of braking power goes to the front wheels which, because of load transfer under deceleration, take the brunt of the retardation duties. (Think of what would happen if you tried to slow down a skateboard with a tennis ball on it).

In one area F1 brakes are empirically more advanced than road-car systems: materials. All the cars on the grid now use carbon fibre composite brake discs which save weight and are able to operate at higher temperatures than steel discs. A typical Formula One brake disc weighs about 1.5 kg (versus 3.0 kg for the similar sized steel discs used in the American CART series). These are gripped by special compound brake pads and are capable of running at vast temperatures - anything up to 750 degrees Celsius. Previously different sized discs would be used for qualifying and racing, but the 2003 changes to the rules means that all cars enter parc ferme after qualifying - and so therefore set their one-lap time on their race brakes.

Formula One brakes are remarkably efficient. In combination with the modern advanced tyre compounds they have dramatically reduced braking distances. It takes a Formula One car considerably less distance to stop from 160 km/h than a road car uses to stop from 100 km/h. So good are the brakes that the regulations deliberately discourage development through restrictions on materials or design, to prevent even shorter braking distances rendering overtaking all but impossible.

Since 2009 teams have had the option of harnessing the waste energy generated by the car’s braking process and reusing it via a Kinetic Energy Recovery System (KERS) to provide additional engine power, which can be made available to a driver in short bursts to help facilitate overtaking.

What is KERS? The acronym KERS stands for Kinetic Energy Recovery System. The device recovers the kinetic energy that is present in the waste heat created by the car’s braking process. It stores that energy and converts it into power that can be called upon to boost acceleration.

How does it work? There are principally two types of system - battery (electrical) and flywheel (mechanical). Electrical systems use a motor-generator incorporated in the car’s transmission which converts mechanical energy into electrical energy and vice versa. Once the energy has been harnessed, it is stored in a battery and released when required.

Mechanical systems capture braking energy and use it to turn a small flywheel which can spin at up to 80,000 rpm. When extra power is required, the flywheel is connected to the car’s rear wheels. In contrast to an electrical KERS, the mechanical energy doesn’t change state and is therefore more efficient.

There is one other option available - hydraulic KERS, where braking energy is used to accumulate hydraulic pressure which is then sent to the wheels when required.

Do the regulations place limitations on the use of KERS? Currently the regulations permit the systems to convey a maximum of 60kw (approximately 80bhp), while the storage capacity is limited to 400 kilojoules. This means that the 80bhp is available for anything up to 6.67s per laps, which can be released either all in one go, or at different points around the circuit. Lap time benefits range from approximately 0.1 to 0.4s.

How is the stored energy be released by the driver? The regulations stipulate that the release must be completely under the driver’s control. There is a boost button on the steering wheel which can be pressed by the driver.

Why was KERS introduced? The aims are twofold. Firstly to promote the development of environmentally friendly and road car-relevant technologies in Formula One racing; and secondly to aid overtaking. A chasing driver can use his boost button to help him pass the car in front, while the leading driver can use his boost button to escape. In line with the regulations, there are limits on the device’s use and therefore tactics - when and where to use the KERS energy - come into play.

Is a car running KERS heavier than one which is not running the system? No. A typical KERS system weighs around 35 kilograms. Formula One cars must weigh at least 620kg (including the driver), but traditionally teams build the car to be considerably lighter and then use up 70kg of ballast to bring it up to weight. This means that teams with KERS have less ballast to move around the car and hence have less freedom to vary their car’s weight distribution. Heavier drivers are at a particular disadvantage, an issue addressed by the raising of the minimum car weight by 15kg for the 2010 season.

Do teams have to use it? The use of KERS is not compulsory. In fact, for 2010 a gentlemen's agreement means no team is using it, though that does not mean it may not return in the future. ENGINE / GEARBOX: The engine and transmission of a modern Formula One car are some of the most highly stressed pieces of machinery on the planet, and the competition to have the most power on the grid is still intense.

Traditionally, the development of racing engines has always held to the dictum of the great automotive engineer Ferdinand Porsche that the perfect race car crosses the finish line in first place and then falls to pieces. Although this is no longer strictly true - regulations now require engines to last more than one race weekend - designing modern Formula One engines remains a balancing act between the power that can be extracted and the need for just enough durability.

Engine power outputs in Formula One racing are also a fascinating insight into how far the sport has moved on. In the 1950s Formula One cars were managing specific power outputs of around 100 bhp / litre (about what a modern 'performance' road car can manage now). That figure rose steadily until the arrival of the 'turbo age' of 1.5 litre turbo engines, some of which were producing anything up to 750 bhp / litre. Then, once the sport returned to normal aspiration in 1989 that figure fell back, before steadily rising again. The 'power battle' of the last few years saw outputs creep back towards the 1000 bhp barrier, some teams producing more than 300 bhp / litre in 2005, the final year of 3 litre V10 engines. Since 2006, the regulations have required the use of 2.4 litre V8 engines, with power outputs falling around 20 percent.

Revving to a limited 18,000 RPM, a modern Formula One engine will consume a phenomenal 650 litres of air every second, with race fuel consumption typically around the 75 l/100 km (4 mpg) mark. Revving at such massive speeds equates to an accelerative force on the pistons of nearly 9000 times gravity. Unsurprisingly, engine-related failures remain one of the most common causes of retirements in races.

Modern Formula One engines owe little except their fundamental design of cylinders, pistons and valves to road-car engines. The engine is a stressed component within the car, bolting to the carbon fibre 'tub' and having the transmission and rear suspension bolted to it in turn. Therefore it has to be enormously strong. A conflicting demand is that it should be light, compact and with its mass in as low a position as possible, to help lower the car's centre of gravity and to enable the height of rear bodywork to be minimised.

The gearboxes of modern Formula One cars are now highly automated with drivers selecting gears via paddles fitted behind the steering wheel. The 'sequential' gearboxes used are very similar in principle to those of motorbikes, allowing gear changes to be made far faster than with the traditional ‘H’ gate selector, with the gearbox selectors operated electrically. Despite such high levels of technology, fully automatic transmission systems, and gearbox-related wizardry such as launch control, are illegal - a measure designed to keep costs down and place more emphasis on driver skill. Transmissions - most teams run seven-speed units - bolt directly to the back of the engine.

Mindful of the massive cost of these ultra high-tech powertrains, the FIA introduced new regulations in 2005 limiting each car to one engine per two Grand Prix weekends, with 10-place grid penalties for those breaking the rule. From 2008, a similar policy was applied to gearboxes, each having to last four race weekends. 2009 saw the introduction of even more stringent engine rules, with drivers limited to eight engines per season. On top of these measures, a freeze on engine development imposed at the end of the 2006 season means teams are unable to alter the fundamentals of their engines’ design.