Monday, November 30, 2009

Getting the Best F1 Start


Any advantage drivers used to gain by jumping the start lights and hoping noone important noticed have now been lost. Electronic tell-tales on the grid position inform the race directors of any driver that has anticipated the lights. A 10 second stop/go penalty or a drive-through penalty (at the discretion of the race directors) is applied to any competitor who does this. In addition, he will look foolish and might have a lot of explaining to do to his team boss at the end of the race.
Formula One cars employ “launch control”, a package of technical gizmos that allows them to achieve their maximum acceleration as soon as the driver presses the button. How quickly a driver reacts to the lights going out is therefore crucial, but every other aspect of getting the car quickly off the line – such as the engine revs and slipping the clutch – is controlled by the software, not the driver. But launch control cannot endow the car with acceleration it doesn’t have; it can only maximise the potential of the car as defined by its power, weight, gearing, and traction. So the one-stopping fuel-heavy car should still be slower away than its two-stopping fuel-light rival.
Those drivers on a heavy fuel load will be extra-anxious to keep any rivals behind them at the start. By preventing a two-stopping driver from passing them, they ruin the lighter car’s strategy by keeping it down to a one-stopping pace but with the extra fuel stop still to make. As the start represents the best opportunity for a light car to pass a heavy one, the driver of the heavy car often needs to be extra ruthless in the dash down to the first corner to keep any rivals from overtaking him.
The sporting rules specifically limit what a defending driver is able to do. The one move rule allows him one blocking move – defined as a move from one side of the track to the other – whereas the driver attacking from behind has no such limitation on his lines. Michael Schumacher has been the most ruthless exponent of this rule over the years; whenever he makes a poor start, he invariably cuts across the bows of any faster accelerating car behind him. Rivals on the receiving end of this treatment, notably David Coulthard and Jacques Villeneuve, have complained about it, feeling that it’s both dangerous and goes against the sporting ethic, but his reply is always the same: “The rules say I can.”
At the start, the race officials tend to concentrate on watching what is happening at the front. Further back, out of the limelight, all sorts of transgressions of etiquette and rules take place. You can get away with murder back there on the hectic opening lap.
You might think it has taken vital skills away from the driver. Don’t be shy about saying this out loud – you won’t find many people disagreeing with you, and, as of 2004, launch control is again going to be banned from use. Traction control remains, so at least you shouldn’t see your favourite driver wheelspinning out too early in a race.

Starting the F1 race


All the preparation – the development back at the factory, the testing, the practices, the qualifying, the debriefs – lead up to the moment of the start. A famous Australian driver once said, “when the flag drops, the bullshit stops”. There is no longer a starting flag but the basic premise still holds good.
The start procedure is as follows:
  1. Start minus 30 minutes and the cars can be driven from the pit lane to their grid positions.
  2. Start minus 15 minutes, the pit lane exit is closed and any car that has not yet left the pit lane will have to begin its race from there after the field has gone by on the first racing lap. This is not a good start to your race!
  3. Start minus five minutes: the grid is cleared of all personnel (except the drivers of course!).
  4. A green light signals the beginning of the warm up (or formation) lap. Any car slow away can only regain its grid position if it hasn’t been passed by every other car. Otherwise, it must start from the back of the grid. Other than passing slow-moving cars with an obvious problem, or regaining a grid position lost due to a slow start, drivers cannot overtake on the warm up lap.
  5. At the end of the warm-up lap the cars take up their grid positions. When the last car is in place, a race official walks on to the back of the grid, signals the race starter with a flag, and leaves the grid once more. The race starter then initiates the starting light procedure.
  6. A series of five lights on the start line gantry (a bridge-like framework set high over the track) come on in sequence. When the fifth light comes on, the race can start anytime between 0.2 and three seconds afterwards (the gap is pre-programmed by the starter before the race but kept secret).
And they’re off! The race is on the moment the lights go out.

Understanding F1 Start


Overtaking wheel-to-wheel on the track is a relatively rare thing in Formula One. On the tightest circuits, such Monaco and Hungary, the total number of overtaking moves in a race is often less than half-a-dozen. Therefore the standing-start acceleration burst down to the first corner will usually represent the best opportunity offered a driver all day of making up places. Aside from being one of the most exciting parts of the race it also has serious implications on strategy.
A two-stopping car with only half a tank of fuel weighs around 60kg less than a one-stopper filled to the brim, a difference of 10 per cent in its total weight. This weight difference has a huge effect on the car’s acceleration away from the start. Similarly, a car on soft compound tyres usually has the traction to accelerate better than one on a tougher-wearing harder option. At a track where the quickest fuelling strategy is delicately balanced between two stops and three, the decision might be swung by the desire to be quick away from the lights. Even at those races where it’s clear which of the stopping options is quicker, a team may still reduce the duration of the first stint in order to make the car light at the start and accept the penalty of below optimum timing of the pit stops. Ferrari drivers Michael Schumacher and Eddie Irvine beat the faster McLarens at Monaco in 1999 by doing just this.

Saturday, October 31, 2009

Pit Stops Considerations

Here are the vital pieces of information the teams will take into consideration:
  • The way you qualify. Because fuel cannot be added or subtracted between Saturday qualifying and the race, the cars have to qualify with enough fuel on board to do the first stint of the race. Obviously a car planning to three-stop can qualify lighter than one on a two-stop strategy. The team needs to trade off the importance of qualifying position with the optimum race strategy.
  • The weight of fuel. This varies according to how dense the fuel is, but the regulations specify the density must be between 0.725 and 0.77kg per litre. The largest tanks hold around 150 litres and brimmed to capacity will therefore weigh around 120kg.
  • The amount of lap time this costs at the track in question. A half-tank car is quicker by around 2.4 seconds per lap around Suzuka than a full tank one, whereas over the similar distance of a Monza lap – with long straights and not many corners – the difference is only around 1.6 seconds. Suzuka therefore errs towards a two-stop strategy, Monza a one-stop.
  • The consumption of fuel. How much fuel (and therefore weight) needs to be put into the tank and how much the car sheds as it races tends to be higher at a track with lots of accelerating, braking, and use of the lower gears. The Hockenheim track, as revised from 2002, induces heavier fuel consumption than any other on the Formula One calendar. Although lap times at the track are only averagely sensitive to weight changes, the big reduction in weight (because of the high fuel consumption) means that the total effect is large. It’s therefore another track favouring a two-stop strategy. At the other end of the pole is Nurburgring where there is relatively gentle fuel consumption but where lap times are highly sensitive to weight. The net result is very similar, and again a two-stop is favoured.
  • Your qualifying position. If your grid position places you in an attacking position – meaning that you need to overtake other cars – you are more likely to opt for an aggressive two-stop strategy, even if the maths tells you that a one-stop is quicker. If it’s a track where pretty much everyone can be guaranteed to be on the same number of stops, you have a choice: depending on whether your strength is early or late in the stint, you can either short-fuel for the first stint, using your lower weight to pass cars and then hope to pull out enough of a time cushion before you stop to keep you ahead after they have stopped. Or you might choose to take on board as much fuel as you dare and hope you can keep up with cars that are lighter early in the race; when you stop later it will take less time as you will not spend as much time refuelling to get you to the end.
  • Other cars and overtaking opportunities. The more pit stops you make, the more you are at the mercy of traffic – of getting caught behind slower cars after your stop but before they make theirs. At a track with plenty of overtaking opportunities this is less of a consideration than at a place like Monaco where passing places are few and far between. The timing of your stop might also be influenced by traffic – for example, you might come in earlier than planned so as to avoid encountering a bunch of lapped cars.
  • How the brakes are wearing. At some circuits – such as Imola, Montreal and Monza – brake wear is extreme. A heavier fuel load places extra strain on the brakes, due to the extra weight and momentum that they are working against.
  • The skill of the driver. The handling balance of the car changes a lot from the beginning of a stint to the end. This change will be larger the longer the stint. Some drivers can cope with handling changes better than others, so it is something that has to be taken into account.

Choosing the number of stops


Pit stops are not actually compulsory in Formula One. In theory, a team could build a car with a big enough fuel tank to do the whole race without stopping, and the tyre manufacturers could easily produce a compound tough enough to make tyre changes a thing of the past. But in reality, such a car would be hopelessly off the pace. Not only would it be slow because of its weight and hard compound tyres, but the bulkiness arising from its big fuel tank would make the car aerodynamically inefficient, slowing it yet further – and all the other teams would laugh at them. All current Formula One cars are therefore designed around tanks that are too small to hold enough fuel to complete a full Grand Prix.
At most tracks, a pit stop – including slowing down, stopping, re-fuelling, and accelerating back up to speed – takes around 30 seconds. The race distance is specified as the least number of laps exceeding 305km (190 miles). (For more on what constitutes a “complete” race, head to “race stoppage” later in this chapter.) Over that distance, and with that time penalty, it did not use to be worthwhile stopping more than twice. But since the 2003 regulations prohibiting fuel loads being changed between qualifying and race (see Chapter 8), stopping three times in a race has become a viable option once grid position is taken into account. Stopping just the once, or even twice, during a race has fallen out of favour after the introduction of these regulations. At some tracks an extra stop is quite feasible, more than making up the extra 30 seconds of pit stop time with a lighter fuel load. Magny Cours, in France, with its very short pit lane and high tyre degradation, is a good example of this. At other tracks the tyres perform close to their peak for longer and the pit lane can be longer. Silverstone in Britain is a good example of this. The most common strategy in Magny Cours is three-stops, whereas for Silverstone two stops is more popular.
Aside from tyre behaviour, it’s all to do with fuel consumption and how much lap time the extra weight costs you. In other words, a team needs to know how sensitive the car’s lap time is to changes in weight and how fast that weight is changing.

Strategy on the hoof


Rarely has the importance of race strategy been so well demonstrated than at Monaco in 2002. Michelin, the tyre suppliers of Williams and McLaren, arrived with a tyre that was of supersoft compound, making it very quick over one lap in qualifying but less so over a race distance. The reasoning was to get at least one Michelin car to outqualify the dominant Bridgestone-shod Ferraris and then let the tight confines of the track aid them in keeping the red cars behind for the race.
It worked brilliantly, demoting Ferrari to the second row. In the race, McLaren’s David Coulthard soaked up pressure from Ferrari’s Michael Schumacher to take victory. Even though the Ferrari was capable of lapping more than 1 second per lap faster than the McLaren, there was simply no way by. In desperation, Ferrari brought Schumacher in a few laps early for his pit stop, in the hope he could use his speed to get and stay ahead when Coulthard stopped. When he rejoined, now on a clear track, he immediately set a stunning fastest lap. This alerted McLaren, who realised that, at this rate, Schumacher would indeed be able to pass when the McLaren stopped. Before any further damage was done, they brought Coulthard in early too, getting him out still ahead of Schumacher. It sealed the result.

Monday, August 31, 2009

Choosing Tyres in F1 Races


Teams can invest small fortunes (actually, make that very large fortunes) in developing race car technology, and drivers can be as brilliant as they like, but when it comes down to it, a car’s tyres are what actually keeps it moving on the track. So, as you might expect, development has crept into tyre design too! The teams are given a choice of two compounds of dry weather tyres from their supplier. The compound refers to the constituent mix of rubber and chemicals of the tyre. The compound choice will usually be between:
  • One that is more consistent and tougher-wearing
  • One that is made from a grippier chemical/rubber mix and therefore usually faster at its peak A team will prefer to be able to use the softer, initially grippier tyre but sometimes they are prevented from doing so if they cannot attune the car sufficiently so that the tyre’s wear rate is kept in check. In this case they will be forced to choose the harder compound.
The compound choice refers only to the dry weather tyres. The tyre company will supply wet weather tyres but there is no choice of compound for the teams to make.
The teams have to choose their dry weather compound before going out to qualify. They are stuck with that choice for the rest of the weekend, so a bit of forward planning is important. What compound they choose depends on the following:
  • The practice laps: The practices give the teams some indication of the wear rates and lap time capability of each tyre, enabling them to trade off one quality against the other in their calculations.
  • Info from the tyre manufacturers: The tyre manufacturers advise the teams after studying the practice data. This will include looking at the tyres’ lap time drop off, the difference in performance at its peak and just before the pit stop. At some circuits, there is virtually no drop-off –meaning that the tyre is still at a peak performance level when the fuel stop is made. At others, notably circuits like Suzuka in Japan that have lots of long duration turns, it is a significant factor.
  • The pit stop strategy: The choice of tyre compound is also linked to the pit stop strategy. If you go for a one-stop strategy, the extra fuel weight may destroy the softer, more delicate compound and force you to opt for the harder, slower, choice.
  • The driver’s skill: Much depends upon the sensitivity and control of the driver. If he can “nurse” the car through the early stages when the car’s weight is high, he may be able to make even the softer tyre “live” and therefore get the benefit of its extra grip as the fuel load comes down. You hardly ever know before the race what tyre and pit stop strategy a driver has chosen, as obviously this is information that could be used to advantage by his rivals and is therefore kept close to the team’s chest. You can always try asking if you get close enough, but they might lie.