ATLAS F1   Volume 6, Issue 52 Email to Friend   Printable Version

Atlas F1   Taking the Lid Off F1

Formula One Technical Analysis

  by Will Gray, England

Last year, Atlas F1 ran a series of articles that investigated the technical areas involved in design, development, and construction of an F1 car. Now, a year later, Will Gray picks up where he left off, and dives deeper into the technical analysis of Formula One.

Part 11: "Material World - Materials"

Carbon Fibre. Two words which have revolutionised the way a Formula One car is built. It is a material from the gods in the view of the F1 designer as it has everything he could want....and more! Until the advent of this magical material, cars were constructed of bent and riveted aluminium sheets. Although aluminium is a light metal, it still made for a heavy car, and carbon fibre offers the same strength of construction for a smidgen of the weight. Its one downside is the hefty price tag.

The BAR HONDA 002 with nose cone removedCarbon fibre comes to the Formula One factory as rolls of cloth. This cloth is made up of strands of carbon 'fibres' woven to form a mat, and covered in a 'resin' - like a glue. The cloths have to be stored in freezers, because if they were left at room temperature, the material would go off quickly, and the resin would become very sticky, making handling the stuff a nightmare. In a way, making a Carbon Fibre part is just like making a pastry tart! The ingredients (Carbon Fibre cloth) are taken out of the refrigerator, and begin to defrost. The cloth is then cut to shape, and put into a mould.

After a number of layers have been applied, the part is baked in the oven for several minutes - gas mark 8. O.K., it's not as simple as that, but you get the idea! A mould is prepared in the shape of the required part, and coated up to eight times with a release agent which enables the carbon part to be easily removed from the mould once it is cured ('cooked'). Then the carbon fibre sheets are cut to shape and pressed into the mould - each sheet is about one third of a millimetre, so if you lay three sheets, you get a part which will be 1mm thick.

The lay up stage is where Carbon Fibre really comes into its own. In making the cloth (not the team's job!) the fibres can be knitted together in any required pattern. Generally, they can be uniform, or unidirectional - which means all the thin strands of fibre are laid in one direction. Unidirectional cloth gives the F1 engineer a very useful property. By laying up the cloths in a certain manner, the composite designer can obtain the precise strength s/he requires in exactly the correct direction. For instance, a suspension wishbone will be majorly loaded in just one way, and the composite designer can design a lay-up pattern to obtain strength in this direction.

However, in this case, many suspensions have failed when a wheel-to-wheel racing moment ends with contact, as the suspension is not designed for this type of loading. Generally though, the designer can obtain the desired strength in the desired direction with fewer cloths, thus saving weight. Another trick is to use honeycomb. The same honeycomb used for deformable structures, when inserted between sheets of carbon fibre top and bottom, gives great strength with minimum weight, but once again, only in one direction. Most of the major parts of the car use this honeycomb to fill out the area, and give structure between carbon skins when a larger cross section is required.

a McLaren right front suspensionOnce laid up, the carbon is covered with a number of cloths (to allow it to breathe whilst being cured), and packed in a plastic bag. This bag is sealed to be airtight, and the air is sucked out through a valve until the part is in a vacuum inside the bag. This is to ensure the carbon fibre is pressed firmly onto the mould, and also offers the required pressure to allow the carbon fibre to cure. The bagged up mould is then put into an autoclave (basically an oven) to cure at a given pressure and temperature over a chosen time - all calculated by the engineer to ensure the part is correctly constructed. Once complete, the manufacturer is left with a part low in weight and high in strength, and items as big as the front chassis and the floor can be made in full this way.

Carbon Fibre, however, is not the only space-age material in F1. In the search for strength with low weight, F1 has discovered an impressive number of advanced but expensive materials. Brakes (which consist of a caliper and a disk) are a particular area of interest. In applying the brakes, the caliper, which is fixed, squeezes onto the disk (attached to the wheel), and slows it down by changing the rotational energy of the wheel into heat energy in the braking system. In doing this, the disks wear down very rapidly, so they must be made of a hard material. This used to be steel, but weight considerations led the designers to Carbon brake disks. The disk wear can be seen in pit stops on some brake-heavy tracks, when the wheel is taken off and plumes of carbon dust cover the pit crew! Ceramic materials are found in engine parts, because of their great insulating properties (they don't conduct heat very easily). You can see this in the fact that you can hold boiling tea when it's in a ceramic mug, but try holding the same tea in a metal mug and you won't be so comfortable!

Although there are lots of non metallic materials in Formula One, many metals are still also used. Aluminium is still one of the lightest of these, although it is not used in a pure form, but more as alloys, which are a mix of aluminium with other metals. In this form, the low weight properties of aluminium can be combined with other materials to give properties the pure aluminium cannot. Wheels use a Magnesium alloy - again because it's light. However, Titanium is the material of the moment, as it is as strong as Aluminium alloys, but even lighter. Teams not only look for light materials, but ultra dense ones too. With the requirement of ballast, but no stipulation for what material it should be made from, teams have been looking at metals that offer high weight in a small volume, so they can position ballast precisely where they want it. This has led them to materials such as depleted uranium, but these have since been banned due to their high cost. All these materials come at a price, but with every gram of weight essential, the immense cost of this is soon overlooked in favour of performance - after all, it's only money!

Pedro Diniz showing us the plank at the 1999 European GpFinally, how could we end consideration of materials without mentioning the most bizarre item in Formula One: The Plank. Although it looks like wood, that material of kitchen tables and garden fences isnít quite up to Grand Prix racing standards! It is, in fact, made of a carbon fibre material which is designed to wear easily when it rubs along the ground, and is used by the lawmakers as a guide to who's getting that little bit more than they should out of their aerodynamics. Cars run close to the floor. Very close. The lower you go, the better your underfloor aerodynamics are. However, if you go too low, the racetrack acts as sandpaper on the plank, and grinds it down. The thickness of the plank on each car is checked after the race, and if the wear is too much, the car is deemed illegal. With mega materials come mega bucks, yet it's quite remarkable that with all these amazing materials, a team can still sometimes be foiled by an overground plank!

Next Week: "Mission Control: Designs on Victory - Who's Who in the Design Office ?"

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