ATLAS F1   Volume 6, Issue 40 Email to Friend   Printable Version

Atlas F1   The F1 Rulebook

  by Will Gray, England

In a series of articles, Will Gray delves into Formula One's rulebook and investigates the in-depth documentation that governs Formula One: from rules defining how the event should be run, to those restricting designers and engineers in technical areas

Part 12: I Will Survive

Crashes are an unavoidable consequence of Grand Prix racing, and the rules aim to make sure that cars protect unfortunate drivers from the powerful impacts that some collisions create. To achieve this, the drivers are cocooned in what has become known as the 'safety cell' - a structure designed to remain intact and protect the driver in the event of an accident whilst the impact is softened as the rest of the car disintegrates around him.

This survival cell is basically the chassis of the car in which the driver sits, and it must run from rearward of the fuel tank (which sits behind the driver beneath the angle of his seat), to a point at least 30cm in front of the driver's feet resting on the pedals. Apart from the cockpit and any small holes for mechanical access, there must be no other openings in the survival cell This is something the team would aim for anyway, as any opening or cut in a closed structure severely reduces its strength and stiffness, and if a part of the chassis is not as stiff as it could be, the twisting that would occur would detrimentally affect the car's handling.

The rool hoop saves the driver from injury or possible deathThe FIA defines a strict set of measurements to ensure that certain areas of the survival cell - particularly around the driver's head - are of acceptable width to protect him. It must have an external width of 45cm at the rear of the cockpit, but can then taper forward (narrowing towards its front), as most chassis do, to a minimum width of 35cm around the driver's knees, with further narrowing allowed ahead of this. This means there is good room for movement of the driver's legs, and that he can complete the exit safety procedure satisfactorily. To ensure good visibility for the driver, the FIA also states that the driver's eyes must be above the survival cell, and that he can see behind him using 12cm by 5cm wing mirrors.

Many leg injuries occur due to objects outside the chassis impacting through the survival cell, and there are rules aimed at reducing this problem. The FIA ensure that the front wheels and their associated suspension are kept as far out of the way as is possible, by stating that the soles of the driver's feet must lie behind the centreline of the front wheels - and in doing so, also provides a limit for the shortest wheelbase to which the car can be designed. Another area that the rules stipulate must be strengthened is the area behind the driver. All cars must have a structure which extends wider and higher than the driver's shoulders, and can take a sideways force of 1.5 times the estimated racing weight (stated in the rules as a weight of 780kg).

With the survival cell being so strong, some of the force from the impact must be taken away from the driver, and teams partially achieve this by designing the car to break up in certain impacts. A good example of this is the way in which Martin Brundle's Jordan broke in two when it rolled in Australia in 1996 - the rear of the car broke away, leaving the survival cell separated from the engine and gearbox, reducing the forces transmitted to the driver.

In addition to this, the FIA demand certain areas have deformable crash structures, which are of specified size, and constructed of collapsible honeycomb between carbon fibre skins. There are four main areas where these are required. The first, to protect from rear impact, requires a deformable structure to be mounted on the gearbox no further than 48cm from the rear wheels, whilst the other three, which protect the driver from side and frontal impacts, are firmly attached to the survival cell. There is one structure mounted on each side of the cell, and one on the front. The latter is basically the nosecone, which itself must be no less than 90 square cm in area at a point 5cm back from its front - a rule which also defines the basic shape of the nose.

How carbon fibre is laid upTo ensure the survival cell itself does not crumple, the FIA states that the outer skins of the cell must be at least 0.35cm thick. Although it may not sound a great deal, this will create a significantly strong carbon fibre part. In addition, each panel inside the outer skins must be created from laying up at least 8 layers of carbon fibre to create a part of minimum 0.2cm thickness. These layers must create a part which has equal strength in every direction, and this is done by orienting each cloth at a different angle, so that four are arranged at 0/90, and the other four at opposing 45 angles. For those of you interested in figures, the basic fibre used must have a tensile strength equal to or above 2.6GPa, with a tensile modulus of 114GPa.

The survival cell also includes the two roll protection structures required by the rulemakers. The 'principal structure', as it is called, is situated behind the driver and must be just under one metre above the reference plane (the top of the plank lying underneath the car), with the second positioned no more than 25cm in front of the steering wheel. Both must have a cross sectional area of over 100 square cm, and to ensure that the driver is fully protected by these two structures, a further rule states that the driver's helmet and steering wheel must lay at least 7cm and 5cm respectively below a straight line drawn between the two highest points on each structure - the danger of a car digging down into a gravel trap by as much as 7cm is slim, so chances are a driver's head will never make contact with the ground.

Inside his safety cell, the driver is safer than he has ever been, but the development won't stop there. The FIA constantly looks to improve its design, and the driver can rest assured that his office will always be as safe as technology allows.

Previous Parts in this Series: Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | Part 7 | Part 8 | Part 9 | Part 10 | Part 11

Will Gray© 2000 Kaizar.Com, Incorporated.
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