Features - Technical
JANUARY 5, 2000
Formula1 Technical Regulations for 2000
BY PETER WRIGHT
There are many vested interests involved in the development of the Technical Regulations. On the one side there are the technical departments of the Teams and engine suppliers, who would like more freedom to innovate and show their technical prowess. The better off departments i.e. those with large resources, staff and budgets, have an advantage whenever the regulations change significantly. They are able to do more research quicker and arrive at the optimum solution faster, gaining a temporary advantage until others less well off, catch up. Pulling in the opposite direction are the Team owners and Formula1 promoters who wish for rule stability and the competitive equality that generates close racing. In the middle is the FIA, which must try and satisfy all parties while ensuring Formula1 exhibits the highest standards of safety for all participants and spectators so that the threat to motor racing that appeared after Senna's fatal accident, never appears again. It is these opposing forces that make it so difficult to make the major technical changes that sometimes seem so necessary to outsiders. The running of Formula1 is more democratic than it has ever been, but democracies seldom encourage revolutions.
Only one of the changes for 2000 is directly performance related, and that is more a cost issue than ultimate performance. From 2001, the use of metallic materials with stiffness to density ratio greater than 40 GPa/(g/cm3) is banned. For 2000, they are permitted inside the engine only. This rule came about because Ferrari discovered that Illmor were using a beryllium-aluminium alloy in the Mercedes engine, for either pistons or liners, and did not want to have to follow suit. The regulation effectively limits the use of the more exotic aerospace aluminium alloys and metal composites, with a cost saving for all.
Many of the changes are to tidy up the wording and clarify the meaning of regulations. While they often appear to have minor significance, they do pinpoint the areas where designers are pushing the regulations hardest. Wording can remain accepted for years until an area of design becomes more important, and someone decides to re-read the regulation to see whether there is room in the way it is worded for a more liberal interpretation. With many of the regulations stable for some time, the opportunities for a performance advance become smaller. Improvements from year to year are the sum of many tiny changes. Particular areas that have come under close scrutiny in the last year or so, are mass and its position, aerodynamics and control software. Take the rule governing the fasteners holding the "plank" onto the bottom of the car. In 1999 it read:
Art 3.13:.É.this skid block É.must:
h) have no more than ten fasteners, each with a maximum area of 20cm2, which are flush with it's lower surface. Any other fasteners must be at least 1mm above its lower surface.
For 2000, this is replaced by:
3.13.2 Fasteners used to attach the skid block to the car must:
a) have a total area no greater than 400cm_ when viewed from directly beneath the car ;
b) be no greater than 20cm_ in area individually when viewed from directly beneath the car ;
c) be fitted in order that their entire lower surfaces are visible from directly beneath the car.
Ten of the fasteners may be flush with the lower surface of the skid block but the remainder may be no more than 8mm below the reference plane.
The reason for this rather esoteric change is that it was discovered that several of the teams were using the unlimited nature of the additional fasteners, over and above the ten allowed as skids, to mount ballast as low in the car as possible. Large areas of the "plank" were being milled away to within 1mm of the lower surface, and filled with tungsten ballast plates. You couldn't get the ballast much lower than that to achieve the lowest possible centre of gravity.
The positioning of mass in the car is so important that designers have pushed the engine as far forward as possible in order to put more weight on the front axle. Because there is a regulation that forbids fuel tank behind the front of the engine, it has become necessary to define the front of the engine more precisely:
Art 6.1.2 All the fuel stored on board the car must be situated between the front face of the engine and the driver's back when viewed in lateral projection. (Added for 2000) When establishing the front face of the engine, no parts of the fuel, oil, water or electrical systems will be considered.
The area around and behind the driver's head, the high cockpit sides and the head padding has been subject to a great deal of attention by aerodynamicists. The airflow over the open cockpit and around the driver affects both the flow into the airbox intake, and hence engine performance at high speeds and flow to the rear wing. For safety reasons, the cockpit aperture size is regulated, but designers have been optimising the cockpit below the rim to suit aerodynamics and compromising the driver's ability to exit the car quickly. The definition of the aperture has been clarified to ensure all cars meet the safety requirements. Additionally, the details of the head padding dimensions around the cockpit aperture have had to be clarified, as they influence the aerodynamics!
Inevitably, the airbox and rear roll structure have been designed as one, fully integrating the intake with the rollover hoop, all in CFRP. For aerodynamic reasons, the whole assembly was steadily moving rearwards, away from the driver's head. Although the roll structures fully met the safety regulations, for 2000 there is a new regulation that stipulates that it must not be more than 30mm behind the template used to check the cockpit aperture, so ensuring that it will provide the best possible protection to the driver.
Since Diniz's rollover accident at the Nurburgring in which his CFRP roll-structure failed on impact with the track, a great deal of thought has been given to these structures. Too late to be implemented into the 2000 cars, there will be greatly increased loads used in the testing required to prove them for 2001. In the mean time the Technical Directors have unanimously and voluntarily agreed to double the current lateral component of the load used in the test, from 12KN to 24KN.
Various other safety related details have been clarified:
A minimum cross-section for the rear impact absorber - it must be at least 90cm2 everywhere in front of a point 50mm forward of its rearmost point. Some of the devices were extremely slender and thus unlikely to withstand a significant lateral force component in an impact.
After one year's application, judged as being a big step forward in controlling loose wheels, wheel tether regulations have been tidied up, but without major changes.
Likewise, the safety seat, pioneered by Lear and Stewart, has been in use for a year. After some problems with standardising the fixing and removal procedures, the rules now state that they must be removable using only the FIA tool issued to the safety crews.
The sight of track marshals struggling to remove an abandoned car from the circuit while it is still in gear is unfortunately all too familiar. The problem arose with the introduction of semi-automatic gearboxes, which do not present a Marshall with a lever to enable him to select neutral. The FIA has mandated a clearly marked Neutral button that will select neutral when pushed, even if the car is broken down, but the performance of these has been patchy to say the least. Most cars are fitted with a system that pressurises the clutch hydraulics, and so disengages the drive when the button is pressed. The FIA has found that it has had to regulate that these devices must work for at least 15 minutes, as some were capable of passing the function test and then the pressure leaked away shortly afterwards. Such is the desire to save weightÉ..
The frontal impact test speed has been raised from 13m/sec to 14m/sec, an increase in energy of 16%. A detail of many of the impact test procedures has also been changed. Where a maximum allowable acceleration figure exists (e.g. the maximum 60g allowed in the dummy's chest acceleration measurement during the frontal test), this is now assessed as a maximum figure exceeded for a cumulative 3 milliseconds. This change gets rid of the problem of very short duration acceleration spikes in the data from the tests.
Two major safety regulation changes come in this year. For some time there has been a worry that the sharp, pointed, high noses of the current breed of cars could impale the safety cell and driver if one car ran into the side of another at high speed. Added to this is the worry that the tethered front wheels (or even un-tethered ones) can swing into the sides of the safety cell around the driver's legs. This is just what happened in Michael Schumacher's accident at Silverstone, the wheel fractured the side of the monocoque, causing the whole front end to break off in the impact. To provide added protection to the sides of the monocoque, the new cars must have the outer skin of the sides of the safety cell at least 3.5mm thick, incorporating a 2mm thick, precisely specified, woven Kevlar/epoxy laminate. The panels must be 250mm high at the front of the monocoque, tapering up to 350 high at the front of the cockpit aperture and back to the rear of the cockpit. This is the first time that specific materials and structure have been regulated, as opposed to a need to meet a test specification, and so the full specification of this "armour plating" is quoted here:
· each ply must consist of continuous aramid fibres reinforcing an epoxy matrix with a resin density between 1.20 - 1.40 g/m_ and resin content between 47% - 53% ;
· the basic fibre properties must meet or exceed the following :
- axial tensile strength : 2.6 GPa
- axial tensile modulus : 114 GPa
- axial tensile strain-to-failure : 2.3 %
· each ply of material must feature the aramid fibres specified above, woven in the following style :
- DuPont style 285 (160-180 g/m_, 4-harness satin) giving a panel nominal thickness of 0.25mm
· the laminate must consist of at least 8 consecutive plies of the aramid/epoxy material specified above ;
· the laminate must have its plies oriented to give quasi-isotropic in-plane properties, at least four being arranged at 0¡/90¡ and at least four at 45¡/45¡.
To check the efficacy of these modifications, the side impact and static load tests have been up-rated. In particular, the static load test in the area beside the driver's legs has been increased from 25KN to 30KN, and located where a tethered wheel would strike the monocoque; and the deflection under load of the static test in the cockpit area reduced from 20mm to 15mm, which should not be a problem with the new "armour plating" fitted.
The Benetton solution to the side impact test - an aerodynamic impact absorber protruding from the lower edge of the monocoque - has been a source of annoyance to the rule makers. Although it meets the wording of the test, it is limited in its ability to protect the driver. For 2001, a new side impact test has been agreed that uses a smaller impactor (30cm x 20cm, compared to 45cm x 55cm currently mandated), and requires two consecutive impacts, 15cm above the reference plane at 7m/sec and 45cm up at 5m/sec, compared with the current impact, 27.5cm up, at 7m/sec. The larger impactor used currently, impacting in the current position, engages the Benetton type absorber; the new regulation's second impact would not, and so the structure would fail. This, new for 2001 regulation, will ensure that the side impact absorbing structures will be effective for a variety of side impacts.
On the thorny subject of control software checking and validation, revisions to the procedures have been made to simplify and make more rigorous the way in which it is inspected. All Formula1 cars have control systems on a CAN network. The car is fitted with a number of modules, e.g. engine, gearbox, steering wheel, hydraulic system etc., each with a microprocessor and its associated software. Off board systems, e.g. the race engineers' laptops, also plug into the network. To check that each and every device adheres to the regulations is becoming a mammoth task for both the teams and the FIA's software police. The new regulations define different classes of device, according to whether they cannot be re-programmed, are re-programmable away from the circuit or are re-programmable at an event. The way each type is dealt with is laid down in the regulations.
Some changes have been made to the specification of permitted fuel, the most significant of which is a reduction in sulphur from 150mg/kg to 50mg/kg. This is in line with the most stringent road car proposals for the EEC. The change may not make a lot of difference to the total emissions put out by Formula1 engines, but it demonstrates the responsible attitude the FIA must portray in its dealings with road car legislators.
One other regulation change that has been recently agreed between the engine manufacturers and the FIA is that engines must not have more than 10 cylinders. It has been rumoured for some time that Ferrari, Honda and Toyota were all looking at V-12's again, in a quest to push RPM figures ever higher. The manufacturers agreed to the limitation on the basis that if one of them built a V-12, and it worked better than the V-10's, they would all be forced to build them. Of course, it may prove even costlier to push the RPM up much higher on a V-10, overcoming inherent limitations. We shall see, but we will not be thrilled by the sound of 24, 18,000+rpm V-12's on full song. What a pity! I hope the fear of ever-escalating Formula1 costs does not prevent a radical re-think of the regulations for 2001. Nor indeed, that the competitive instinct to disagree with anything a competitor agrees to, is allowed to get in the way of constructive changes for the future. It will be a few more weeks before the radical 2001 regulations emerge, and the engineers rush off to their wind tunnels to start work on re-gaining the lost downforce, but let us hope that what is decided among the participants will be sound enough to last for some time, and provide Formula1 with the sort of racing all enthusiasts yearn for.