Dan Fallows: Making the perfect F1 car chassis

The virtues of carbon fibre...
09 July 2024

Interview with 

Dan Fallows, Aston Martin

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Carbon fibre

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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 - Through these doors?

Dan - Yes. Through here. So the first and most important thing is the absolute backbone of the car, which is the chassis. That's where the driver sits in there. It's incredibly tight. It's a very claustrophobic place to sit. He sits with his feet up around the level of his chest, so it's almost like lying in bed, so that we have as much available area for us to do all of our clever management of the airflow around the car. We also even mould the seat to the driver himself. It's a very thin layer of carbon fibre that sits underneath the driver. We need to make sure that that's moulded specifically to his dimensions so that he sits as comfortably and as tightly in the car as humanly possible.

Chris - Carbon fibre is a relatively new material. What did we use before we had that?

Dan - Originally cars were made with aluminium and metal, a bit like road cars have been for a long time. The problem is that as we are trying to make cars lighter and more complicated, and particularly to be able to make very complicated shapes, but in a way that's still very structurally strong and stiff and safe, then carbon fibre is an absolutely ideal material to use.

Chris - To get that winning combination of something that is strong, doesn't have a lot of material in it so it's really light... How do you design that? What's the trick to that?

Dan - We do a lot of development work to make sure that we are making the car as strong as it needs to be but obviously as light as it needs to be. You can imagine there's a kind of tension between those two things. We want to make sure that we're not overweight, because any extra kilogram you have on the car is going to slow it down, but we also need to make sure the driver is safe. Also, when the car is going around the circuit, things don't move around more than they should do. So we accept that things are going to move around at speed because air is incredibly strong and there's a lot of force on the car, but we want to make sure we minimise that effect.

Chris - Can you embed sensors in the carbon fibre in order to see where the stress points are, how it's being loaded, how it's performing, so that you can gather data on the track as it were?

Dan - It's one of the great advantages of carbon fibre. You can embed things in it and particularly sensors. There are key parts of the car, like the suspension, which is the little stick like arms that hold the wheels on. It's incredibly important to us that we understand what the loads are that are going through those members because we need to know firstly that they don't go over the loads that we believe that they may break at, so we need to make sure that the car is always safe at all times. But it's also very useful for us to know what those loads are on the car. There are hundreds of sensors on the car that we are reading as we go around the lap. Some of those are telling us about loads, some of them are telling about pressure, literally the pressure of the air as it goes around the car, which informs us about how much down force or how much force there is pushing the car onto the ground. We can measure all of that as the car is going round.

Chris - When I was at Rolls Royce in Derby, looking at jet engines, they told me that they take the pieces off of their engines in order to see how working life is affecting them in order to understand how the materials age. And so if you are building these cars bespoke for each race, do you almost do a postmortem on the car materials after each race? Do you pull them apart, have a look at how the race has affected them and so on?

Dan - We do that every single race, yes. We take the cars completely apart. They don't stay together. They go into their component parts and either get shipped to the next race or they do exactly what you're talking about and we strip them down and ensure that the parts that we have run in the race are still fit for purpose. We also do a lot of research work here at the factory to make sure that parts that are going to be able to last the number of races we think.

Chris - So how much of the car is actually carbon fibre and how much is good old fashioned steel or aluminium; heavy duty stuff that can take a bit more punishment,

Dan - I think, as a percentage, I would say probably 90% of the car is carbon fibre. The other parts are things like brackets. There's obviously the steering wheel and the steering column. Those parts of the steering column that connects the steering wheel to the wheels, a lot of that is metallic. In reality, anything we can make from carbon fibre, we tend to.

Chris - In order to inform what the shapes of that carbon fibre should be to get those aerodynamics so you are not basically wasting energy moving air around - and I suppose the other important function is that it gives you important force downwards onto the road for road holding, doesn't it - how do you arrive at those shapes?

Dan - Well, we have a team of people that work in the aerodynamics field. We do a lot of testing in a wind tunnel which we're building here on site. We also do a lot of testing inside the computer. We can actually simulate a car going around the circuit and how the air goes over the car inside a computer simulation. We do a lot of work on that. Really the aim of all of that is to try to balance making the car as fast as possible in a straight line with really doing what the tyres are asking us to do and what the tyres want. It's true, on any car, that, in order to go around a corner faster, they need more vertical loads. They need more pushing down on them. So effectively the harder you can push down on the tyre, the more grip it will have, the more ability it will have to get you to go around the corner faster.

Chris - Is there not a sort of tension there because, you want to slow down a bit to go around a corner, but to get that down force you need lots of air pushing the car down over the various spins and structures you've created. So is there an optimum speed to go into a corner, then, to do it fast but to have more control?

Dan - Yes. Yes, there is. The person who's the arbiter of all of that is the driver, really. He's the one who will tell us whether we've done a good enough job with the car going into a certain corner. There are things that we can do with the car to make sure that it's optimised for certain corners more than others. Every circuit we go to has a slightly different layout which means that your priorities are maybe slightly different. We can set the car up differently for those circuits. So for somewhere like Monaco, you basically put as much downforce as you can on the car, and the places like Monza in Italy, it's a lot about straight line speed. So you take all the downforce off the car really. We have to try and think about those even while we're designing the car, but also race to race.

Chris - So we've done what it looks like, how it holds the road from an air flow point of view. Where should we talk about next and where's next on our trip?

Dan - So I think the next thing to look at is, as we go slightly further down the corridor, where we're actually manufacturing the car. We have a large facility here at Silverstone where we're manufacturing the metallic parts of the car, the brackets and all the other things we talked about. But I think if you can bear the background noise, then I think it's really worth having a look at.

Chris - Let's go and take a look.

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