Technology in the Eye of the Storm

Throughout most of the year, the major story in Formula One has been that of the spy scandal. While the practice of teams spying on each other, at differing levels, has been going on since the sport started, this year the acceptance of what is permissible boiled over and led to two teams being hauled in front of the governing body's World Motor Sport Council (WMSC).

The witness statements and evidence made available to the public by the FIA give a unique insight into some of the workings of the modern F1 car. This rare access gives us the opportunity to look at some of the systems on an F1 car, and explain their importance.

Data gathering

Formula One teams keep a closer eye on one another than most people realise.

We know that the teams take detailed photographs of each other's cars, and that they monitor tyre usage and fuel loads as closely as external observation allows.

From the witness statements in front of the WMSC, it's clear the teams are also analysing in-depth on-board footage of rival cars to assess what the driver is controlling within the cockpit, and geometric details such as steering angles.

This type of analysis can help teams to understand concepts that their rivals are employing, be it from simple arrangement of parts on the car, to how the team might be working around problems with braking, for example.

In studying this type of material, the teams also try to derive quantity figures. This is possible because all the cars have to fit within such tight dimensional boxes, meaning that relative dimensions can be calculated.

For example, wheels have a fixed diameter, so taking that dimension from a long-range side-angle photo, wheel base or layout dimensions can be established with a degree of accuracy.

Where technology is hidden due to its position on the car, or by its nature as a function of the car's electronics, external observation is impossible.

The exchange of staff between teams is frequent, and clearly an expert going to another team will mean a degree of knowledge transfer, even without hard data being involved.

Thus, concepts and some detail can be interchanged. Teams understand this, and the long notice periods (often served as gardening leave) serve to protect recently-developed technology from being passed from team to team.

Braking

The braking power of an F1 car is already well understood. Equally, it's fairly easy to understand that the grip available for the tyres to brake the car varies as the car goes through the braking process.

As the driver initially applies the brakes, the weight of the car shifts forwards, away from the rear wheels and towards the front wheels. This makes the rear wheels less effective at braking. Thus, in the early stages of the braking process, the rear tyres could easily lock, as they aren't pressed as hard against the ground.

Then, as the car's weight shift stabilises later in the braking phase, the rear tyres can contribute more to the braking effort. So what this means is that the teams have to find a compromise between locking the rear tyres or having them provide less braking effort.

What is more, this weight shift effect varies depending upon the gradient of the track and the speed differential from corner approach to corner entry.

Clearly, the braking from a 200 mph straight into a 50 mph chicane will bring a different weight shift to a brush of the brakes between two sweeping corners.

Thus, the bias required for the ideal lap will be different for nearly every corner. Adding further dimensions to the puzzle is the fact that as tyres wear, the track gains grip, or the car's fuel load lightens, the bias may need to change.

Distributing the brake force has to be done with a passive system. Unlike the active systems of the nineties or on road cars, the electronics cannot intervene and alter the braking bias front to rear.

Like most race cars, Formula One car's brakes use a simple bias bar assembly acting on two master cylinders to control the braking effort front to rear.

The single brake pedal had a pivoting bar attached to it. To each end of the bar is a master cylinder, one for the front brakes and one for the rears. By altering the relative length of the bar each side of the brake pedal, a different bias between front and rear can be achieved.

Additionally, the bore size of the master cylinders (around 19mm) will be different for the each cylinder, further altering the split front to rear. These settings will provide the static braking bias of around 54 percent to the front depending on the track and conditions.

To alter this split, the driver is provided with an adjuster inside the cockpit, sometimes termed a 'prop valve' (proportioning valve).

Usually, this is a knurled knob to the right of the driver's legs. The adjuster can be screwed in or out to alter the position of the bias bar on the brake pedal, altering the ratio of effort applied to each master cylinder, and therefore achieving a different bias setting.

With the screw-type bias adjuster, there's a near-infinite range of settings between maximum and minimum. To simplify things for the driver, some teams adopt a stepped adjuster, which provide a smaller set of fixed positions for the bias lever.

From on-screen footage, we've often seen a driver altering the bias during the race. Michael Schumacher was well-known for adjusting the bias through a lap, particularly in qualifying, to achieve the ideal settings for each sequence of corners.

But although it is adjustable, a simple adoption of this solution cannot alter brake bias during an individual braking operation.

Managing brake bias was a particular problem for teams in 2007, as the new-spec Bridgestone tyres provided less stability at the rear and more at the front. McLaren stated they had problems with rear tyres locking and needed a solution to resolve the problem.

QuickShift

It transpired that Ferrari have used a different form of adjuster to alter their brake bias for several years. Although the evidence was redacted to limit the exposure of Ferrari secrets, it is clear that Ferrari's prop valve was more complex than just a stepped adjuster.

McLaren were looking at on-board footage and believed that the adjuster was most likely a driver-operated bias adjuster which could be set for one section of the track before resetting to a default position.

The latter part of this suggested that the driver did not need to manually return the adjuster to a different setting after the initial adjustment, saving him time and complication. Thus, it is plausible that the adjuster had a linkage to the brake system to detect that the brakes had been used, and reset the adjuster.

Looking at recent on-board footage of Ferrari qualifying laps, the driver can clearly be seen to make a quick single movement with his right hand to an adjuster to the right of his leg on the dashboard bulkhead.

However, looking at the cockpit of the Ferrari, there is also a bias adjuster to the right side of the driver's seat. One conclusion could be that the dash bulkhead-mounted adjuster is the 'preset-able' bias, while the side-mounted adjuster is used to tune the bias in the manner of a threaded adjuster.

This would offer the drivers a simple way to optimise the bias for a sequence of corners, as well as allow them to make the fine adjustment required to trim the car through changing race conditions. It would not necessarily provide a huge advantage, but is a sign of the meticulous detail a leading team goes into to find advantages.

Fast fill

While the cockpit-adjustable bias control is used around the lap to trim the car, the issue of the bias needing to be optimised during a braking manoeuvre is not something that can be practically achieved by the driver.

What is really needed is a solution that will create greater braking power toward the front brakes on the initial part of the pedal travel, before increasing the rate as the speed is shed. This problem gave rise to McLaren's brake locking problems during testing in early 2007.

Again the evidence has been redacted, but it is clear that Ferrari, with longer experience of the Bridgestone tyres, had a solution already in place for 2007.

The answer is believed to be in the way the master cylinders work. As a master cylinder effectively acts like a syringe to produce the pressure in hydraulic brake lines, its fixed bore will create a fixed pressure increase as the piston is depressed.

It seems the Brembo master cylinders can produce a dual rate as the piston depressed. While this is not widely advertised, Brembo engineers have explained the solution to media in the past. This solution was termed 'fast fill' by McLaren, as it bears some relation to the master cylinders commonly in use by road cars.

A fast fill master cylinder employs a stepped bore, and accordingly, a two-part sprung piston. The initial piston travel uses the large bore to quickly create an initial pressure, then the next part of the pedal travel uses the smaller piston to create a smaller rise in pressure.

This is used to give the front brakes the important initial boost in pressure. Then, as speed is shed and weight shift is reduced, the front and rear brakes achieve a more equal gain in pressure.

Fast fill or dual rate master cylinders are patented by several manufacturers, and are adopted largely to manage the bias for road car tandem master cylinders. Some of these patents do relate to McLaren's brake vendor Akebono.

In the F1 environment, it is likely that only the master cylinder for the front brakes has a dual rate, with the initial cylinder bore being larger than that of the rear master cylinder.

This solution provides the boost the front brakes need to allow a balance later the braking phase. If the quick-shift braking mechanism does not offer not a major gain in lap time, then this solution clearly is.

This is particularly true where a circuit demands heavy braking from high speed, although the different bore sizes and the strength of the piston spring could be tuned to provide a lesser effect for tracks with less heavy braking.

Tyre gas

Which gas the teams use to fill their tyres might seem to be a rather mundane and unimportant fact. However the gas does have a critical impact on the tyre pressure and, to a lesser extent, temperatures.

The rate the gas expands with heat will increase the tyre pressure as the wheels/tyres heat up around the lap. Equally, the ability of the gas to conduct heat away from the inside of the carcass is important in managing tread temperature.

This cooling effect reduces the tyre's tendency to blister. When the construction of the tyre is cooler, the tread temperature can be higher without creating the bubbles between the tread and carcass.

There are a lot of myths surrounding the gas that teams fill their tyres with. It is often thought nitrogen is universally used, however Bridgestone have stated that dried air is the normal gas used. This saves the supplier the effort of shipping gas canisters around the globe to fill the tyres once they are mounted to the rims.

The confusion probably comes about as the teams use nitrogen cylinders to adjust the tyre pressure in the pits as they do not have the compressors and driers in the pits that Bridgestone have access to.

That said, when we say 'nitrogen', the gas the teams have access to is more specific than that - they use oxygen-free nitrogen. This reduces the other gases that are in the cylinder, and ensures that the pressure gain is what is predicted from nitrogen.

If a team was able to find a gas that is more thermally consistent and cools the tread from inside to a greater degree, it would be highly advantageous. Again, the facts have been redacted from the evidence, but there is now a common belief that Ferrari use carbon dioxide (CO2) as their gas.

The actual gas mix that Ferrari use is probably something more complex than simple dried CO2. Indeed, there is a patented tyre gas that consists of only 50 percent CO2, the balance being HFCs (hydro fluoro carbons).

According to its patentee, based in Monza, Italy, this gas mix keeps both a consistent pressure as it heats, reduces inner temperature and offsets blistering compared to that of pure nitrogen. Again, this would provide real benefits in tyre consistency and durability.

J Damper

One technology that emanated from the Renault affair was the existence of novel damper technology from McLaren. Termed the 'J Damper', little was revealed about the device in the evidence, but what was explained was the damper is a response to the 'Tuned Mass Damper' and its banning in 2006.

McLaren were one of the teams believed not have run a mass damper. At the time, the team stated their suspension obviated the need for the mass damper. Around the same time, Koni was marketing a series of road car dampers with a frequency selective damping technology. Probably not by coincidence, Koni are McLaren's damper supplier.

Mass dampers were introduced to offset the natural bounce of the tyres. This spring effect of the tyres is at a lesser frequency than that of the bumps the damper manages, but greater rate than that of body roll/pitch.

Additionally, as tyres are made of rubber, their stiffness is different in bump to that in rebound. Both this very low and higher frequency movement require different damping rates, with stiffer rates for the body roll and softer rates for the bumps. Meanwhile, the tyre needs a damping rate somewhere in between, and different in both directions of travel.

Renault mounted a mass on a spring and damper arrangement to offset this unwanted disturbance. Meanwhile, Koni developed an additional oil circuit in the damper rod that can be set to work more in one direction than the other. It is not clear whether McLaren do, in fact, use the Koni FSD solution in their F1 cars.

Confusing this matter yet further was the revealing of another novel McLaren suspension technology with a spinning mass. In the Renault evidence, this was explained as a spinning mass mounted inside the damper. This does not appear to be a part of the Koni FSD technology.

Quite how the mass was spun inside the relatively small damper housing and how it would improve the compliance of the damper is not clear - certainly not for Renault, who didn't appear to fully understand its purpose from the drawing Phil Mackereth had of the device.

It seems that this device was the object of Renault's request for clarification from the FIA on the device's legality.

Any ability to reproduce the mass damper effect is going to be a real advantage, as the mass dampers were originally worth a few tenths. If the solution can be recreated within a conventional damper then it should still be legal, however the concept of a spinning mass inside the damper could be more contentious.

We want to hear from you!

Let us know what you would like to see from us in the future.

Take our survey

- The Autosport.com Team

Read and post comments