Dan Fallows: Making an F1 car's tyres, gearbox and engine

A split second can make the difference...
09 July 2024

Interview with 

Dan Fallows, Aston Martin

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F1 track

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In this edition of Titans of Science, it’s the turn of the British Formula One engineer Dan Fallows. He’s currently technical director at Aston Martin and took us on a tour of their base in Silverstone...

Chris - So we've seen how you basically make the things that then become the visible outer, but also some of the other bits of the car. We've talked about the fact that going very fast involves good air profile and so on, and how that gives you also forces down to keep the tyres on the road. What do we need to talk about next?

Dan - I think the next part we can see as we walk down here is the area where we actually put the cars together. It's a very important area for us because obviously there's a huge amount of work that goes into all the different components, but the most important thing is it all comes together in a coherent car. That's a surprisingly big challenge. Once we get to the point where we do have a car, we then need to start thinking about how we're going to operate that at the racetrack. One of the things we do here in what we call our race base is we put the cars together and we also have an area where we can practise our pit stops. The mechanics can practise putting the car together as fast as possible. One of the things that you can imagine does occasionally happen at the circuit is that we have an accident, we have a crash. Sometimes, if you ever watch Formula One, you see that there's parts flying off the car which all looks very alarming. But one of the things that we do when we're designing a car is to make sure that, in the event of a crash, the energy that's involved in that crash is dissipated into those parts. When you see parts flying all over the place, that's usually a good thing for the driver because that energy is being used into flinging those parts around the circuit rather than actually going into the driver themselves.

Chris - A bit like crumple zones which we engineer into cars to absorb the energy and slow down the rate at which it's transmitted from the thing you've driven into, to you.

Dan - Exactly that. We have some of the technology that's been developed in Formula One now in road cars in that respect. We can see a car here again, and there are some large areas of the car which are actually dedicated to exactly those crumple zones. There's a part of the front of the car we call the nose which holds on the front wing, the very large aerodynamic device at the front. That in reality is just one large crumple zone. We have two of those zones on the side of the car and then another one at the rear. If you look at the very top of the car, on the part just behind the driver that looks like a snorkel, that has a number of functions: it's an air intake for the engine itself for some cooling and also it is actually a roll structure. A very stiff structure so in the event that the car flips over and lands on that, it will not break and it will protect the driver. You could put two double decker buses on the top of that and it would still not crumple. So it's incredibly important that those things are able to withstand high stresses and also the energies of a crash.

Chris - Are those the sorts of forces that, at the sorts of speeds they're doing, they're going to be experiencing, then?

Dan - They really are. From when we talk about the downforce on the car, we measure it really at top speed in tons.

Chris - Really? So if that could drive upside down, say, at full speed, you could probably drive that upside down and it would have enough force holding it onto the ceiling.

Dan - It would be nowhere near top speed. I think the last time I looked at it, I think it was about 80 miles an hour that it could drive upside down, drive on the ceiling. So by the time you're doing a hundred miles an hour, it would easily be able to stick itself on the ceiling.

Chris - I thought that might be the case. I'm still amazed.

Dan - It's extraordinary and I think sometimes, when you are designing the car, you sort of forget about the forces and just what we're asking this car to do. The amount of work that the tyres are doing, the amount of energy that's involved in the whole thing is absolutely staggering.

Chris - How much of this can you actually change track side during a race?

Dan - Clearly the longer time you spend not going anywhere, the worse that is for your overall race performance. We try to make sure that we spend as little time stationary or in a pit stop as we possibly can. But the things you can change once you're in a race are quite a few. But, the majority of the time we would just change the tyres. We can change those in just over two seconds, which is quite an extraordinary thing to see. All four tyres and wheels. We can change those in around two seconds but, if necessary, for example if we have some damage on the front of the car, we can change the front wing, again, in a matter of seconds. Also, even if the driver has a comment about the way the car is behaving, we can make some small changes to the car, particularly on the front wing if we need to. But in general, when you see cars come into a pit stop, it's generally just to change the tyres and then go out as quickly as you possibly can.

Chris - Are you in conversation with the driver during a race or is it a one-way flow of information? You are feeding them tips and things?

Dan - We are in constant conversation with the driver. The driver has a race engineer who's a single point of contact, one person they can talk to and they're telling them about how the car is behaving, what they might want to do at the next pit stop if they did want anything changed. But I think more importantly the race engineer can tell the driver a lot as well. They can give you some situational awareness of what's happening in the race, managing the tires and the way they behave is a critically important thing for us. We have an enormous amount of data that comes off the car that tells us a lot about what we might need to do, how we might like the driver to be driving the car, and communicating that to them is obviously a very important job.

Chris - That's real time flowing in off the car to you track side so you can see all the different operating parameters?

Dan - Literally hundreds of parameters that we can see. We have a number of engineers at the circuit that travel around with the race team and the car and they'll be looking constantly at the data as the car is going round on track. We also have another area which you can see just up the stairs from here, which is called mission control, a little bit like on a space programme, where we have another 30 engineers who are looking at the data again, live from the circuit, and everybody will be looking at something slightly different just to make sure that all the systems on the car are working exactly as we want them to.

Chris - Can we talk about the tyres for a minute? I changed the tyres on my family car recently. It cost me an arm and a leg. How much would one of those cost and how much does each one weigh?

Dan - We have a deal with our tyre supplier Pirelli. So they supply all the tyres for the race. Fortunately, we don't have to buy them individually. We have an arrangement with them over the whole year. But I dread to think how much one of those would cost. We use over the course of a race weekend, normally two to three sets of tires on each car in the race. Then we have several other sets that we use during the race weekend so it'll normally be another two or three sets that we use in each of the practice sessions. Then another three sets in qualifying. You can imagine 10 to 12 sets of tyres that we have available for the whole race weekend. That's not including in case the weather changes and we need to start using the wet tyres, we also have sets of wet tyres that we can use as well.

Chris - The demands placed on them are considerable. Their job is to get the force onto the road, propelling the vehicle along, translating the energy that's coming out of your engine. What are the specifications you're looking for in tyres like that? Do you need a certain kind of rubber that changes its temperature and operates in the very warm? How do you get them to perform right and what are the right conditions?

Dan - The structure of the tyre itself is designed to make sure that the contact patch, so the part of the tyre that's touching the road, is as big as possible at any given time. That's important because the bigger that contact patch you have, the more adhesion you have, the more ability you have to generate grip with that tyre. So that's why we have, compared to a normal road tyre, the size of what we call the side wall - the height of the tire relative to the wheel itself - is quite tall. That's all about making sure that as the tyre is being pulled sideways by the car, that it still remains in contact with the road as much as possible. Then, the rubber on the outside of it is a very carefully designed compound which is sensitive to temperature, so we need to make sure that we keep it within a certain operating range. But when you get it to the right temperature, which is around 80 to 90 degrees centigrade, the rubber becomes incredibly sticky. When you get it into that range, you know that combination of the downforce on the car and that very sticky rubber means that the grip and the lateral acceleration you are able to generate on the car is absolutely enormous.

Chris - Upstream of those tyres is of course a gearbox and an engine.

Dan - The engine is a very important part of the puzzle for us. We have a certain amount of fuel that we're allowed to use, just over a hundred kilos of fuel that we can keep in the car, and that represents an amount of energy that we have to spend.

Chris - And what is that fuel? Is that kind of unleaded like I buy on the forecourt or is it some special blend?

Dan - It is a special blend, but in truth it's more similar to road car petrol than you'd think. It is an unleaded fuel, the same that you would be able to buy in a normal forecourt, but it has, yes, some particular additives to it to make it particularly suitable for these engines.

Chris - So can you tweak what you put in that fuel?

Dan - There is a certain amount of variability. Different teams have access to different fuels which have different compositions. But in general they're very similar.

Chris - You have a hundred kilos of fuel, you have to make that last a race. How does that get factored into how you make the car perform?

Dan - There's always a trade off between the amount of power that your engine can generate and how efficiently you can use that fuel. The other thing is that we have a hybrid engine. We have what we call an energy store, but it's basically a posh name for a battery. That is able to be charged and deployed at certain times during the circuit and we get a power output of 120 kilowatts out of that battery. It's a large amount of power that we can use. Then there is a very clever system inside the power unit itself where it recovers energy from the braking system. So every time the car brakes, it generates energy through an electric motor essentially, which then puts energy back into the battery. We have on these engines also another very clever piece of technology. Because these are turbocharged power units, we can use the energy from the excess energy from the turbo, from the exhaust gases to also put electrical energy back into the battery as well. Those sources of energy are all things that we can use to improve the efficiency of the engine.

Chris - When you think about how an electric motor works, it's at its best when it's not moving at all, and a petrol engine is at its best when it's got quite a bit of speed already. So I suppose the combination of the two of those, you're sort of filling in for the shortcomings of the other?

Dan - Absolutely right. It's one of the things that we're able to play games with as we go around the circuit. So for example, when you first get on the accelerator coming out of a corner, we bias the power output much more to the electrical power delivery. Then, as the car gets faster, that tails off and it becomes far more about the internal combustion engine, how you use that power delivery, and then also how you recover the energy at the end of the straight is a thing that we spend a huge amount of time trying to balance correctly.

Chris - We are increasingly in our conversation talking about strategic aspects of this. Obviously a lot of this is going to come down to the driver. Does the car learn the track or does the team behind the car learn the track as the car's going round, take some of that data and then tweak some of those things you've been talking about on the fly so that you can optimise performance even during a race, as the race progresses?

Dan - We've been limited in recent years in terms of how much we can actually allow the car to learn which we would like to do because, frankly, computers inside cars would probably do a lot better job than even us humans. But we can certainly preempt some of the things that we might want to do. So the driver, particularly if we have a look at the steering wheel, you can see that there's a lot of knobs and buttons which seem a bit sort of superfluous for just steering the car left and right.

Chris - It actually looks like a sort of game controller on steroids that you would have on your Xbox or something, but with a lot more buttons.

Dan - It does. And they're all brightly coloured as well which really adds to the effect, I think. But some of these dials are also to do settings on the car that he can adjust as he goes around. Now we predetermine what those are, but it really is something that allows him to adjust the behaviour of the car. So things like the rear differential, which is a part of the rear power delivery to the rear wheels, that can be adjusted as he goes around. Or the way the brakes work on the front axle, the rear axle, all of that can be adjusted by the driver in order to allow him to get the best behaviour that he can out of the car.

Chris - Are you also, because we've talked very much about how you're keeping tabs and what the machine is doing, are you keeping tabs on what the driver's doing physiologically? Are you monitoring the driver's heart rate, blood pressure, that kind of thing, reaction times? Are you collecting that sort of data to help them to learn and become better with each race?

Dan - We've, in the past, left it up to the drivers to make sure that they're able to do what they need to do. I think the ones who are performing the best are usually the ones that have prioritised that in their training and so on. We have in recent years started to pay a bit more attention to how the drivers are doing as they're going round. It's a bit less important in Formula One than it is in some other things. There are racing series like Le Mans 24 hour races where drivers may have to drive three hours at a time, and that's far more important. So they spend a bit more time worrying about how the driver is performing physiologically.

Chris - I'm not gonna watch Formula One the same way ever again.

Dan - Well hopefully you can see that there's maybe a lot more to it than meets the eye, but it's certainly, I think, a fascinating sport from the technology side of things as well as just the racing itself.

Chris - And when you became an engineer, did you see yourself standing here? Not talking to me today, but did you see yourself doing this as a job? Is this something you grew up thinking, this is what I want to do?

Dan - For me, this was always a sort of collision of really loving cars and also being very interested in aerodynamics. I was originally much more interested in aircraft, but as soon as I realised that you could combine those two interests together, it was really all I ever wanted to do. The thing about working for Formula One is it's incredibly high paced and at times a very high stress job, but it's never, ever boring. That's a good thing for me.

Chris - Dan, I can't thank you enough. It's been a pleasure.

Dan - Likewise. It's been a pleasure speaking to you.

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