An average Formula One pitstop takes an unbelievable 7 to 8 seconds. 24 men form part of the Williams pitstop crew and can change four wheels and fill a petrol tank with 60 litres of fuel in the time taken to dial a phone number. We asked our Team Manager, Tim Newton, to take us through a typical pitstop.
Q: To begin with, how does an engineer work out the optimum number of stops for a Grand Prix?
TN: Each Grand Prix is roughly 200 miles in length. This distance, divided by the length of the circuit, obviously gives us the amount of laps for the race, while the culmination of the shortest average lap time is the quickest way to get to the end of the race. The lap time will always be affected by the amount of fuel that the car is carrying and on which circuit, this can be by as much as 0.4 tenths of a second per lap per 10 kilos of fuel. Combine these factors with the level of tyre degradation and the length of the pitlane, and our engineers can determine the optimum strategy for a particular circuit.
Q: How many people are involved in a Williams pitstop?
TN: We use 24 people in total to carry out our pitstops; three men on each wheel, one on the front jack and one on the rear, three on the fuel hose, two for the “dead man” (these are the guys responsible for shutting off the fuel cell should there be a leak during the pitstop), one for the spare hose and one on the control desk. We also have two men with fire extinguishers and then lastly the lollypop man, bringing the total to 24.
Q: What goes on just ahead of the pitstop?
TN: At the start of each race, we have a loose plan of when each car will be coming in. I say loose because you always have to be ready to react to changing track conditions: safety cars, accidents or performance issues. If everything is going according to plan, though, it’s a routine set of processes. As the pitstop approaches, it’s my job to check with the relevant race engineer what the next set of tyres should be and whether any adjustments need to be made to the car during the stop. I also make sure that our Chief Mechanic is aware what is required. I can then call the driver into the pits. At this point, our crew make their way into the pitlane and get ready for the stop (this can be as late as 20 seconds before the car arrives). Before he’s due to enter the pitlane, I remind the driver to watch his speed and to make sure he drives into the box smoothly and squarely as the crew are all lined up in their designated positions.
Q: Pitstops are such a precise art. Can you explain what each person does?
TN: As the car comes down the pit lane at 100km/h and drives into the pit stop area, the gunmen are ready and waiting; crouched on the balls of their feet with the wheel guns held at the same height as where the wheel nut will be. The driver knows exactly where to stop because the guys that remove the front wheels hold their fluorescent coloured gloves at the exact height of where the front wheels need to be so the driver has a reference point.
As the car stops, the gunmen immediately push the socket onto the nut, often before the car has even stopped. As the socket goes onto the nut, it disengages a locking device (which prevents the nut coming off on the track), they then pull the trigger to activate the gun and undo the nut. The pneumatic impact wrench which undoes the central wheel nut runs at quite a high pressure (about 24 bar) and will do the wheel nut up to 450lbs of torque. The guns are quite heavy and have a big torque reaction. This process of removing the wheel nut takes about one second.
At the same time that the nuts are being removed, the front jackman has lifted the front of the car and his counterpart the rear. The nozzle man has locked the hose onto the refuelling coupling and slid down the engagement handle to start the fuel flowing into the tank at 11 litres per second (compare this to how long it takes you to fill your car with 60 litres of fuel at your local garage, probably in the region of 3 - 4 minutes).
The guys dedicated to removing the front wheels (and make any front wing adjustments) now remove the wheels (giving them a thump with their inside hand to make sure they do not stick). The gunmen move back, clearing the gun from the middle of the wheel and switching the direction the gun operates. The third person on each wheel now fits the new wheel, moving it as it goes on to make sure it is fully engaged.
As the gunmen do the nut up on each wheel and the guys on the fuel rig have put nearly 40 litres of fuel into the car, the clock is ticking and about 2.5 to 3.5 seconds have passed. At this stage, the radiator ducts are checked for debris and cleaned if necessary and the pneumatic pressure will have been topped up.
To signal that they have finished and the nut is tight, the gunmen hold their hand above their respective wheel. Having engaged the wheel locking device, the front and rear jackmen will let down each end of the car when they see the signal confirming that the wheels are tight.
The pressure now falls onto the lollypop man who has to now look in several different directions at the same time to ensure that all the wheels tight, that the pit lane is clear, that the refuellers are finished, that the debris has been removed from the radiator ducts and any other specific requirements have been completed.
As soon as the wheels on the back of the car are tight, the lollypop is rotated so it now has “Gear” instead of “Brake” displayed to the driver. At this signal, the driver blips the engine revs to about 12,000rpm, selects first gear and gets ready to go.
Refuelling is now almost complete and the nozzleman is getting ready to pull the hose off as fast as he can. His sidekick has hold of the second handle on the rig and is also getting ready to pull, while the third man on the fuel rig has repositioned himself on the fuel hose so he is also ready to help get the hose out of the tank. When the green light comes on, it’s time to pull as hard as possible. As soon as he can see a gap between the hose and the car, the lollypop man lifts the lollypop to release the car into the pit lane (having checked if the green board is being held up to confirm that fuel has actually gone into the car). Between 5 and 7 seconds have passed at this point, depending on the amount of fuel that has gone into the tank.
Q: To accomplish all of that in under ten seconds is an amazing achievement and a great display of team work. How do you do it?
TN: The team carries out pitstop practice approximately 50 to 60 times over the course of every race weekend, mostly on Thursday afternoons, Saturdays (when the cars have gone into park ferme) and at 0800 on Sunday mornings before breakfast. We also practice at the factory between races where we have a car used just for pitstop practice. As a result, the crew will practice between 1,500 to 1,600 times per year!
Q: What thoughts go through your mind when you’re in the midst of a stop?
TN: Our crew are all very competitive and want to do a good job. Everyone is important in the pitstop and the smallest fault can cost vital seconds which are very difficult to make up on the track. The hardest thing to describe is the adrenalin that goes through you during a stop. It doesn’t matter how long you’ve been doing it, it still rushes up and grabs you unawares. Keeping your cool and not letting your emotions get the better of you is therefore vital in the build up to, and during, the stop. If you give out the wrong instructions, or call the wrong set of tyres, it’s all over before you have a chance to change your mind.
Q: You must be relieved when it’s all over then?
TN: One thousand, two thousand, three thousand, four thousand, five thousand, six thousand, seven thousand. The time taken to count to seven thousand is the total time it takes to change four wheels, fill 65 litres of fuel, clean the radiator ducts, adjust the front wing and send the car back out on to the track. It’s all over in a short space of time and, when it is, we can go back into the garage, sit down and try to work out where the car has come rejoined the race. It isn’t long, though, before we get that 20 seconds warning all over again to tell us that the next car is coming in!
No comments:
Post a Comment