Features - Technical
NOVEMBER 15, 2001
BY PETER WRIGHT
The only part of the cars that are regularly and intentionally exposed to the public gaze and the probing eyes of the cameras is their exterior surface. While technically important due to its influence on the aerodynamics, the visible surfaces are all a product of experiments in wind tunnels, and so it is almost impossible to put together a coherent theory to write about the function of each turning vane, fence, and flip-up that comprise the latest developments.
An alternative and risky approach to trying to understand what is going on and to try and detect new developments and trends, is to examine the rumors that pop up throughout the season. On the basis that there is no smoke without fire, one can test these rumors with engineering logic and see whether they stand up. If they do, they may represent the tip of an iceberg and give a hint to what may be under development. This approach is somewhat similar to the Web sites that take the rumors that abounded following 11th September's attacks on the World Trade Center and the Pentagon, and attempt to either validate them or expose them as urban myths.
The 2001 season started with the usual dark hints about who was using traction control in the first four races, before the new regulations permitting traction control, launch control and fully automatic gear changing came into force at the Spanish GP. Confusing the issue was Ferrari's veto on their introduction at the start of the year. Why? The conspiracy theorists claimed it was to give them an advantage at the start of the season, based on the supposedly "well-known fact" that they always used traction control. Ferrari said that it was to give themselves enough testing time with their new engine to fully sort out the reliability prior to committing the systems to races. The test one can apply to these opposing viewpoints, is whether those who were "known to be not using traction control" caught up with Ferrari from Spain onwards. The introduction of traction control freedom appeared to make little difference to the pecking order or the gaps between teams, so either it makes little difference (if this is true, why would Ferrari risk disqualification for a tiny gain?) or all teams started equal in Spain. The problems that many engine suppliers had in keeping their engines together while messing with the firing of the cylinders, confirmed that Ferrari's stance was well justified on their part, and tends to indicate that they were not well practiced in the art at the start of the year.
I should probably devote a paragraph here to all those who absolutely "know" that Ferrari were using traction control since whenever they started winning, but I think I will just take it as read, and save the space.
As an aside, it is interesting that Ferrari will start the 2002 season with the car they used at the end of 2001, delaying introduction of their new car until around April. The testing ban during the winter has made it harder to be ready for the new season in March, and Ferrari set so much store on reliability that they have made a similar decision about introducing new systems and parts, to the one they made last year when vetoing the traction control regulation.
The legalization of launch control certainly had an effect on the outcome of races - mainly by causing several cars to fail to leave the line, either at the start of the parade lap or the race. By the tail end of the season most cars would launch reliably and most drivers had learned to initiate the system successfully. However, the Benetton drivers demonstrated a series of sensational starts, epitomized by Fisichella's start at Spa, gaining himself and the team their best result of the year. By the end of the season, rumors began about Benetton being able to detect the turning off of the jump-start detection system, triggered by the automatic start of the race, and being able to automatically launch the car, avoiding the driver's reaction time to the lights being turned off. This is unlikely to be true as not only is it illegal, but the FIA still carries out software inspections. The regulation that came into effect in Spain states: "Any system, the purpose and/or effect of which is to detect when a race signal is given, is not permitted". While the rumored system allegedly detects when the jump-start system disables, it does also detect when the race signal is given, indirectly. Additionally, observers watching practice starts at the Pit Lane exit, comment that the Benetton starts, which must in these cases be initiated by their drivers, are always immaculate and quick. Perhaps the Benetton and Renault boffins just know what they are doing.
One of the more bizarre early season rumors was that Williams had a new brake system/material and that was why other people kept running into the back of them. Presumably the suggestion was that their brakes were superior to others', and that as with heavy braking on the road, it caused those behind to tailgate them. The total fallacy in this argument is that, while on the road braking is cued by the brake lights of the car in front, in racing each driver has his brake point for a given corner. A higher rate of deceleration allows a driver to brake later, and unless the driver behind just plain leaves his braking until he sees the car in front slow (which would be pretty rash), better brakes should mean that you get hit up the back less often. It is more likely that Williams's BMW-induced higher top speeds, and possibly slightly lower cornering speeds at the start of the season, caused the drivers to brake earlier than expected.
The next brake rumor involved Ferrari's brake cooling system that appeared at Imola, and probably caused Michael Schumacher's retirement in the race. The large drum that is fitted inside the inner face of the wheels and fits closely to the wheel rim led to speculation that they had fitted some sort of impeller inside it to pump air to the brakes. While everyone knows that fans are not permitted, could it be that Ferrari were arguing that the brake disc itself is a centrifugal pump, so where does the brake start and the aerodynamic device stop? In truth, they would never get away with an argument like that (shades of the Brabham fan car's cooling system) and what they were doing was to direct the airflow that exhausts from the brake after it has done its cooling job. Raising the front wing for 2001 had changed the aerodynamics more than expected, and the whole system of front wing endplate devices, bargeboards etc. needed redevelopment. The flow of air from inside the wheel became more critical and Ferrari were trying to seal the inner face of the wheel and direct all the flow to the outside, where it does less harm to the flow under the car and into the radiator cooling ducts.
Schumacher's problem was reputedly something to do with the duct or a stone jamming against the duct and machining a groove in the wheel until the air leaked out. Most cars now have their own versions of these brake ducts.
The biggest myth was undoubtedly the verbal protests of "Unfair!" raised when Fisichella didn't change his front Michelin tires while running so well at Spa. When Williams started the race in Japan and went out after each pit stop with used Michelins, the voices rose to a wail. Of course there is nothing that states that you either have to change your tires after a pit stop or have to start on new tires, so what was the problem? The issue is that the Michelins seem to get steadily better as they wear, and some competitors construed this to mean that Michelin users were running near slicks. However, the regulations are quite clear that the grooves must be visible. Additionally, the FIA checks that dual-compound tires are not used, i.e. ones that wear down to near slicks quickly, and then stabilize.
More intriguing, were the rumors of a suspicious smell emanating from the Bridgestones that Michael Schumacher had fitted for Qualifying and the race in Suzuka, when he stormed away leaving the opposition trailing in his wake. Do teams employ special staff for the dangerous activity of tire-sniffing as cars leave their garages? Of course, tire dosing is not new. Dragster tires are treated with bleach for burn outs, model racing cars use methyl salicylate (oil of wintergreen), and all sorts of products, even brake fluid, have been tried on tires in most formulae over the years. Tire companies usually refuse to supply their tires if this risky practice is found out, so why would Bridgestone condone it, even if there is nothing in the regulations to stop it?
Perhaps more to the point, why would Ferrari disclose a technique at the last race of the year, when the Championship is long settled? Either they want to test the regulations and force a clarification, or they were having a bit of fun. Bridgestone may have a dosing technology, and wanted to ensure they won in Japan - a bit like Honda's Suzuka specials - but surely they do not intend to make it a regular practise; why give the game away when there is nothing to gain? It does not make sense, but maybe we shall find out next year if the source of this smoke really is a fire.
Shape Memory Alloys (SMA) have been around for a while, and it was inevitable that someone would either use them or accuse someone else of using them. Mutterings have started this year, but specific accusations are somewhat vague. What are SMA's, how do they work, and how could they be used in Formula 1?
SMA's are alloys that display two distinct crystal structures or phases. The temperature and internal stresses determine the phase that the SMA is at. Martensite exists at lower temperatures and stresses, and austenite exists at higher temperatures and stresses. When a SMA is in martensite form at lower temperatures, the alloy can easily be formed into any shape. When the alloy is heated, it transforms from martensite to austenite, in which phase it "remembers" the shape it had before it was deformed.
SMA's also demonstrate high rates of super-elasticity. An example is the frames of spectacles, which at room temperature are in a martensite phase. Bending of the frame arms causes a phase change to austenite where the stresses are high. Austenite is not stable at room temperature, and so will change back to the martensite phase (a lower energy state), and in doing so the frames bend back to their original shape.
SMA's have a memory transfer temperature, which is the temperature at which the alloy changes back to the original shape before deformation. The temperature can be very precise - within one or two degrees Centigrade. The most common SMA is NiTinol, made up of nearly equal parts of nickel and titanium. Its memory transfer temperature can be in the range -50 to 110 degrees Centigrade, depending on composition and heat treatment. Heating is the only way that most SMA's retain their original shape, and so heat can be used to manipulate the shape by training.
The most obvious application in motorsport for SMA's would be to use them to change the shape of a component that had an aerodynamic influence. "Illegal!" I hear you cry, but it is a bit more complicated than moveable aerodynamic devices not being permitted. Every structure must deflect to a degree when loaded, and the FIA stipulates a test to check for acceptable levels of deflection for most of the key aerodynamic parts of Formula 1 cars. However, if the material properties change significantly and result in a different deflection depending on which state the material used is in, would that be illegal? Obviously the scrutineering tests would confirm the load-deflection characteristicsÉ..while the car was static. A change in temperature of a key part of the structure, once the car was running, could easily lead to a change in aerodynamic properties.
Obvious components that would benefit from such an application of SMA's would be the rear wing incidence (one might not get away with this, as competitors tend to photograph rear wings and compare incidences while the suspect car is travelling at high and low speeds and in the past this has caused all sorts of aggravation that was the stimulus for the FIA's tests). A better and almost undetectable application would be for the undertray to gain some curvature while running due to deflection of its mountings, but to be flat when checked. The potential ground effect downforce that could be generated from a small degree of curvature would be well worth the complexity of controlling it.
Towards the end of the season, rumors appeared about Ferrari's new gearbox for their 2002 car. They were keen to test it before the winter ban took hold, and the stories circulating hinted that it dispensed with a normal clutch, but had two other clutches in it, developed in conjunction with their technical partner Sachs. Various possibilities spring to mind. Porsche developed a twin clutch gearbox some years ago for their Le Mans cars. It permitted gear changes without loss of torque to the rear wheels during ratio selection. Because it took the urgency out of gear changing, it also gave the selection/engagement mechanisms a much easier time, useful in a 24-hour race. Formula 1 gearboxes can change up in less than 20 milliseconds, the loss of acceleration being almost undetectable, and they usually last the required 2 hours, so it is unlikely they have gone this route.
A couple of year's ago, I was talking to Keith Duckworth about torque-steer transmissions, and he told me of a Kart transmission he had built and run in 1998. It was based on ideas about differentials they had been playing with in the years following the 4WD Cosworth Formula 1 car. The final drive sprocket drove the rear wheels via twin clutches, operated by paddles on the steering wheel. If the Kart understeered, the inside wheel's clutch was allowed to slip, the greater torque delivered to the outer wheel helping to steer the Kart into the turn. Very simple and, if computer controlled, the perfect torque-steer transmission. However, according to Rory Byrne, this would contravene the latest regulation that forbids "Any system or device the design of which is capable of transferring or diverting torque from a slower to a faster rotating wheelÉ" so I doubt Ferrari are doing that!
This has all the qualities of a good rumor: something significant and interesting is definitely going on in Ferrari's transmission department, but it is not at all clear yet what that is. We shall have to wait a while for this one to develop, until it becomes clear just what they are up to and whether it is the start of a new approach to Formula 1 transmission design, which all will have to follow. When testing starts again in the New Year, maybe we shall be able to learn more, but for now it will have to remain a source of speculation to intrigue us during the long winter months.