Andy Green: It’s impossible to test all concepts

For Aston Martin, the 2022 season started with an unpleasant surprise – on the track, the car proved to be seriously inferior to its rivals. Aston Martin Technical Director Andy Green explained how engineers struggled to build the car and why such a concept was chosen…

Q: Why are the cars of different teams so different from each other?
Andy Green: Because no one has seen any cars other than their own. There are a few similarities between some machines, but the starting field has shown how many different solutions there are in theory.

We didn’t have time to fully evaluate each of the options – we had to choose a concept based on a small amount of data. It was impossible to evaluate all concepts in such a way to understand what potential lies in each of them. You won’t know until you pick one and start working on it in detail.

In addition, during work it is impossible to switch between different concepts – this is a road to nowhere. At some point you have to make a final decision.

Q: When was the decision made at Aston Martin?
Andy Green: In July-August last year, when we received the latest rear suspension upgrades from Mercedes. This put certain restrictions on us, but it didn’t make us go our separate ways. Rather, it convinced us in the chosen direction.

Q: What were the difficulties?
Andy Green: Since we didn’t see any other cars and had no data from the track, we could only move in theoretical direction. When developing a new machine, you can compare the results with previous specifications.

Only now, when all the cars have left the track, it is possible to evaluate alternative options and understand which one is most effective. As this work progresses, the differences between the machines will become smaller. This will become noticeable this year, in 2023 the cars will be more similar, and next year the differences will only be in the details.

Q: What affects suspension geometry?
Andy Green: We strive to get the most out of the “ground effect”. To do this, we chose the height of the suspension, which in our opinion gave maximum efficiency. Based on the selected parameters, the general shape of the machine was designed. We have come a long and difficult road and in our simulations the car got better every step of the way.

We saw the target, so we thought we were on the right track. None of our simulations hinted that there could be issues with machine instability.

Q: Do you mean the swing on the straights?
Andy Green: Precisely. This slowed us down. Frankly, this problem has slowed everyone down, but some don’t feel it that much because their cars were originally designed for high ground clearance. The teams that chose our concept have big problems because the car loses a lot of speed if the ride height is set higher than intended when the car was designed.

Q: How are you now?
Andy Green: The problem was only detected after the first turn to the circuit. Now we are trying to find a way out, but this cannot be done overnight. This is a complex process and now we understand that the phenomenon was the result of new rules. Some have done better, others worse. We belong to the second group.

Q: Would your car be much faster if you could tune it the way you intended?
Andy Green: That would solve some of our problems. Now you have to choose settings for which the machine is not intended. That’s why it doesn’t generate the level of downforce it could.

The suspension geometry is not designed for such settings, the front wing is not designed to be placed at such a height above the track. The list of compromises is very long, but as a result we lose lap time.

If we set up the car so that the driver doesn’t lose control of control due to swinging on the straights, so that he can brake smoothly and not wear out the tires too quickly, then we lose speed.

Question: This year only conventional shock absorbers and springs are allowed. Do these limitations also prevent you from solving the build-up problem?
Andy GreenA: They certainly don’t help. Sophisticated hydraulic suspension systems are banned, making the problem more difficult to solve, but when done right, anything is possible. When the car starts to swing at a speed of 250 km / h, incredible forces act on it. A conventional damper with 30mm of travel can’t handle this, of course.

Question: The build-up starts from a speed of 250 km/h?
Andy Green: To build up, two factors must be added together – a certain speed and a certain ground clearance. When we talk about speed, the pressure of 250 to 260 km/h is strong enough to push the car onto the track. But, as I said, the build also depends on the ride height.

In addition, the faster the track, the more time the car is in the critical area. Asphalt bumps can cause the buildup even earlier.

Q: Do you see any light at the end of the tunnel of this problem yet?
Andy Green: We see it, but we don’t know if there is an exit from the tunnel ahead or another train. Currently, we are making great efforts to understand and get rid of the problem. We are convinced that we have found a solution, but this search required enormous resources.

Now it makes no sense to think about how to make the car faster. We know that our machine is capable of more, but to realize its potential, it is necessary to solve the problem. Of course other teams say the same.

Q: How long does it take?
Andy Green: It makes no sense to put novelty after novelty on the machine – it costs us resources without making progress. The season is still long, so it’s better to spend more time and get everything right than to rush and bring a non-working solution to the track. We are hurt by the current situation, but it is important to have a good car for the remaining two-thirds of the season.

Q: Is it possible to change the concept during the season and move to the concept that follows Ferrari?
Andy GreenA: Depends on the team and how much money you have left. Budget constraints force us to work extremely efficiently. In addition, there are restrictions for working in a wind tunnel. Now the teams that were in the second half of the pack last year have a lead in that regard. They have more opportunities to implement radical changes.

Q: How often will we see updates this year?
Andy Green: Updates will appear less often, but they will be large.

Q: It seems that the Ferrari car is the most efficient from an aerodynamic point of view. Do you agree?
Andy Green: Given the build-up on the straights, aerodynamic stability is what all teams strive for. Once the car starts to wobble, you lose lap time. Making modern cars stable under all conditions such as wind, different tire compounds, type of track and so on is a very difficult task.

The Ferrari car is stable and efficient – this is its strength. If the car is stable, you can go fast. In other cases there is a loss of speed.