Not so heavy metal.

Formula 1 involves a lot of crazy technology. Fact. You only need to look at the Lucky Strike BAR Honda 006, even clothed in all its secret-enshrouding bodywork, to see that. Catch a glimpse of the 006 naked and the mind boggles at the intricacy. Go deeper, and you'll discover precise engineering all the way down to the microscopic, and even atomic, level.

Much of it is way beyond the grasp of the average Jenson Button fan, of course. Or even a Takuma Sato fan for that matter. But even a slightly technically savvy fan of either driver could tell you something about the craziness of the metals used in F1 these days. Or at least they would think they could.

The common perception is that the metals used on F1 cars are always exotic: alloys used to land things on Mars, made from metals found only in meteorites in the mountains of northern Uzbekistan; metals that could support the weight of Great Britain in a single fibre the width of a human hair, but that are as light as polystyrene...

The reality, says BAR's deputy technical director Gary Savage, is a little less crazy.

"It's a bit of a fallacy in the business actually that we use lots of 'unobtanium'. We don't. We use a couple of fancy metals and we have used fancy metals in the past - but it's not so much the metal you use as the way that you use it."

Why go crazy?

Just as in composite technology, the drive for exotic metals comes from a desire to increase a material's stiffness. This reduces the mass required for a component to have a given stiffness - allowing the mass saved to be redistributed more optimally around the car, thereby enhancing performance. Alternatively, an increase in stiffness will enhance the performance of a stiffness-dependent component with no associated compromising gain in weight.

Specific stiffness

If you take the standard aluminium alloys in everyday use - steel, titanium, magnesium, all the basic engineering metals - and divide the stiffness of that metal by its density, you end up with the same specific number of 25GPa/cc.

If you do the same with carbon fibre, you get 140GPa/cc. So the bigger that specific number, the better.

"In the mid-1990s we came up with an alloy that had a specific number of 75GPa/cc, which was aluminium-beryllium. In effect we ended up with a material that was as light as aluminium but as stiff as steel," says Gary.

If ever there was an example of why teams should go crazy with their metals, this is it. By simply changing the brake material on their cars to aluminium-beryllium, teams could instantly save around 0.4sec per lap for an investment of just ?25,000.

However, as is often the case when F1 takes a huge step-up in performance - and 0.4sec overnight is certainly that - the sport's governing body, the FIA, stepped in to ban such space-age materials, specifically targeting aluminium-beryllium. In order to enforce the ban with maximum effect, the FIA limited the specific stiffness of any such materials to 40GPa/cc.

Of course, 40GPa/cc is still stiffer than the standard specific number of 25. So, far from stamping out the technological drive for enhanced metals, the FIA actually drove the technology on. How so? Because the teams that had been happily using aluminium-beryllium all had to spend a huge amount of time, money and resources researching materials that would fall just inside the new artificially imposed legal limit for specific stiffness. After all, there was still performance to be gained by that extra 15GPa/cc, so the race was on to find it by other means than aluminium-beryllium.

Enhancing your mettle

The only way to improve the stiffness of a metal is by adding something to it. You can do all sorts of heat treatments to make a metal stronger but these won't make it any stiffer.

The standard method is to add particulate of a harder material to the metal. With aluminium alloys the most common thing added is silicon carbide powder.

"It's exactly the same principle if you take cement and add pebbles to turn it into concrete," says Gary. "It's a basic principle of technology that's been around a long time, just like modern carbon fibre composites are an updated version of a principle used by the ancient Egyptians in brick manufacture.

"As a great philosopher once said: 'There are very few advances in science, just lots of applications waiting for the technology to catch up.' So, the advanced metal matrix composites that BAR use to make uprights (wheel hubs) for example are, in effect, concrete."

Application

So, where on the car are exotic metals used?

As Gary is keen to point out, the team will only use an enhanced material if there's a specific need for it.

"There are people who think that we'll spend a million pounds on some exotic metal to save a tenth of a second. We won't. The majority of things we use are readily available 'off the shelf'. It's the way you use those materials and the way you understand them that makes the difference. How you understand the properties, how the stress engineers use finite element analysis (FEA) to help the designers optimise the structure of components."

Over the past 20 years there has been a great rise in materials technology. Consequently, there is a much wider choice of materials available for Formula 1 teams to exploit. The key, however, is not to use as much or as many exotic materials as possible, but to recognise the unique properties of certain materials and tailor them to specific jobs on the car.

Putting this into context, of all the metals titanium has the highest strength per unit mass. So, if you have a component on the car that is specifically limited by its strength, you would use titanium. Conversely, in something like an upright you're limited by stiffness, rather than strength, because you don't want it to deflect. So, you go for an aluminium alloy with silicon carbide added for a high specific stiffness.

In practice, of course, the requirements of a component are far more complex than simply being "strong" or "stiff", as are the nuances in the specific properties between individual alloys. The examples above, however, are very basic examples to illustrate the principle under which BAR operate - one of engineering pragmatics dictating material (exotic or not) application, rather than exoticness dictating usefulness.

Less exotic than you think

So, while there are a couple of exotic materials, including metals, that BAR do use, these are used primarily to fulfil a purpose for which nothing else would suffice.

For example, there are specific heat shields on the rear of the car that protect the bodywork from the enormous temperatures generated by the exhausts. This material is a carbon-fibre reinforced ceramic. "If that material were not available, we'd have to put the exhausts somewhere else," says Gary. "Either that or we'd have a heck of a lot more bodywork fires."

The majority of work is down to clever design, not exotic materials. While it is true that things like titanium or magnesium alloys are not everyday materials on road cars - and therefore F1 materials seems exotic by comparison - the truth is that F1 cars are more like jet-fighter aircraft than cars anyway. The materials and technology used in F1 are generally common place in the aerospace industry. Exoticness is all relative.

Gearbox of tricks

One place things do get particularly clever on the BAR 006, however, is the carbon-composite encased gearbox, which is very much Gary's baby. Not in the sense that he did all the work, but in the sense that this is his particular area of expertise:

"We use, for wont of a better word, exotic materials in the gearbox internals, on the gears themselves. If you think that you are putting 900bhp through them from an engine that's revving anything up to 19,000rpm - the bit that has to transmit that power is always going to be vulnerable."

The actual materials BAR use on the gearbox internals are the sort you'd find in very high quality helicopter rotor-blade transmission systems.

"I can't tell you anything specific about these materials," says Gary, "but basically you're looking for a very high toughness. The actual gears come together at extremely high velocity, so you've got to have very special materials that can take those loads and still deliver optimum performance. Therefore the material's impact performance is particularly important."

The gearbox internals are a classic example of an engineering requirement dictating the choice of material.

"We have a requirement of a certain component in a certain area, and to achieve the job that component must have certain properties. So, we go out and find a material with those properties. We don't first have a material with lots of properties and then find something to do with it. It's the other way round from what most people expect."

Regulating the future

In order to further cut the performance and cost of developing Formula 1 cars, the FIA plan to limit specific stiffness even further, down to 32GPa/cc, perhaps as early as 2006.

"Inevitably we'll have to research metals that meet the new 32GPa/cc limit. Or, we might find that it's more advantageous to start making certain metal components out of carbon. Either way we'll find our way around it," says Gary.

However, many of the materials BAR currently use are readily available in aircraft technology, so it is unlikely that the team will save money on the replacements, as Gary explains:

"It's like the aluminium-beryllium brakes situation. Everyone had them, and to save money the FIA banned them. But of course we had to pay again to get another material that just met the criteria. The FIA even allowed us then to use aluminium-lithium alloys instead - which, again, were aerospace materials. So we just replaced one expensive material with another."

And so it will be over the next few years, as the symbiotic but often strained relationship between the FIA and the teams enters its next phase. But then, Formula 1 engineering has always been about which team can best explore the limitations of the 'formula', as set down by the FIA. If nothing else, the FIA's recent proposals to cut cornering speeds and reduce costs will push people like Gary Savage and Geoff Willis [BAR's technical director] into ever more ingenious solutions.

Make no mistake: however the regulations may change over the years, F1 will always remain at the pinnacle of motorsport, both in the performance of the cars and the technology behind them.

As a great deputy technical director once said: "There are very few advances in Formula 1; just lots of regulations waiting for the engineers to catch up."

And catch up they will. Some sooner, some later. But this, ultimately, rather than the hunt for unobtanium, is the real difference between winning and losing the battle for engineering greatness in F1. Long may it continue.

Feature courtesy of the BAR Honda Lucky Tribe media site.