Paddy Lowe on the science of F1 overtaking and what it means for 2017

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On the face of it, the prospect of faster Formula One cars in 2017 is attractive. The sport's visceral appeal has always been its speed, and the potential for new lap records at every round is entirely possible under next year's aerodynamic regulations. But the laws of physics rarely allow win-win situations and there are increasing concerns that 2017's changes will have an adverse effect on wheel-to-wheel racing.

As the April 30 deadline for the signoff of the regulations approaches, arguments for and against the faster cars are becoming increasingly political. The 'yes' campaign, led by aerodynamic powerhouse Red Bull, argues the proposed changes do not go far enough, while the 'no' campaign, led by current champions Mercedes, warns of a detrimental effect on the racing. The irony is that while F1's decision makers have been arguing about how to make F1 faster, the natural development of the cars has seen qualifying times come close to or beat lap records at the opening two races of the season. As a result, it is becoming less clear what F1 is trying to achieve in 2017 and increasingly worrying what it could be about to sacrifice.

The science of overtaking

As Mercedes' managing director (technical), Paddy Lowe sits firmly in the 'No to 2017' camp, but he is also one of just a few people in the paddock who has dedicated extensive time to understanding the science of overtaking. In the mid-2000s overtaking was at historic lows in F1 (far lower than it is now) and the sport responded by setting up the Overtaking Working Group (OWG). The group was led by the sport's three top technical directors at the time, Lowe (then working for McLaren), Pat Symonds (Renault), Rory Byrne (Ferrari) as well as the FIA's Charlie Whiting. With a budget of €0.5 million raised collectively from the teams, an independent wind tunnel and McLaren's state-of-the-art simulator, the OWG embarked on a research project to understand how aerodynamics influence overtaking.

"It was the first time some real science had been applied to the subject of overtaking and I think it's useful to go back to that time," Lowe told ESPN. "Remember that in the mid to late 2000s the big story and the big problem with Formula One was overtaking. It was said there was no other problem with Formula One except overtaking, and various things had been tried and talked about before finally it was decided that we should actually do some proper work.

"Some very interesting results came out of it and many of them were not intuitive as well. The paddock is full of amateur aerodynamicists, amateur overtaking experts and car wake experts, and actually when you get into the experimentation you find that things were not actually as you expected."

Both then and now the "amateur overtaking experts" called for the underside of the car to be exploited for aerodynamic advantage through the use of ground effects. But the work of the OWG suggested that would be a retrograde step.

"The brief going into the project was that you wanted it all in the floor, all ground effects, and take the wings off the car -- even now everybody says that," Lowe explains. "A lot of the pieces tried were around those themes and we also had the Central Downwash Wing [a concept to split the rear wing into two sections].

"The first interesting thing that came out was that the Central Downwash Wing actually acted negatively on the following car and made it worse, but not far off that was having no rear wing at all. The best thing was to have a rear wing as we did, but refine it by having it narrower and higher. The reason is that the flow structures and the two vortices at the top of the two endplates are very strong energisers of fresh flow to re-energise the wake, whereas if you have no rear wing you end up with a very messy wake that hangs around. These two vortices bring in fresh air from the sides and dispel the low energy wake that's there. So actually you need a strong rear wing and, adjusting a few parameters, you can make it even more effective. That was unexpected.

"The second point is to work on the front wing of the following car because it is the first part of the car to see the replenished wake. We found that an important aspect is to have a disabled centre section of the front wing, so that it is working just off the outboard ends low down. Those were the two major findings."

Downforce discourages overtaking

The work of the OWG can still be seen on the wings of today's cars, but the 2017 regulations will do away with the tall and narrow rear wing while the front wing will widen in line with the wider track of the car. The impact such changes will have on overtaking have not been tested to OWG levels, meaning F1 could unwittingly undo much of its hard work next year. But there was another key finding by Lowe, Symonds and Byrne that was never realised and is even more significant for 2017.

"The thing that is forgotten is that there were two outputs from the OWG," Lowe adds. "The other half of the story was to halve the downforce. We actually ran some tests in the simulator with a car following and attempting overtakes around Barcelona. The reference point was that the following car needed two seconds per lap [of performance advantage over the car in front] to overtake and the objective was to get to one second per lap. We achieved that, and half a second came from the geometry [of the wings] and the other half came from the halving of the downforce."

A loophole in the regulations allowing teams to develop double diffusers meant the halving of the downforce was never delivered. As a result the OWG's work did not have the impact it could have achieved in 2009 and it was not until 2011 and the introduction of DRS and Pirelli's degrading tyres that overtaking reached all-new highs. But Lowe believes the success of those somewhat artificial devices are underpinned by the work of the OWG.

"Things are better than they were in the mid-2000s because we've brought in things like the DRS, which in my opinion, and I can't prove this, doesn't work on its own but works in combination with cars being able to follow each other. You need to follow in the previous turn to take advantage of DRS and make it work for you. It doesn't work as a standalone.

"The other thing we've got is a big difference between different cars on different tyres at different states -- that's been far more prevalent in the Pirelli era. We also got rid of refuelling, which was a big discourager of overtaking at the end of the day because you're better to overtake with fuel strategy than doing it the hard way on the track.

"We're not in a terrible place at the moment, but it is getting worse and in the last three years we have seen an aggressive reduction in the amount of overtaking and an increase in the level of complaints we get from drivers that they couldn't follow or get near the car in front. That isn't a surprise to me because we are at that point in the aerodynamic cycle where it is time for a reset and to go back down to a fresh lower level of downforce, as we have done over the last 20 years.

"We have periodically reset the aero to stay within a certain window and at the moment we are at a historic highs of downforce, so it would be time to go lower and that would give a benefit in car following and recover where we were in 2013.

"But we seem to be going the other way [for 2017]! We don't agree with that at Mercedes for a range of reasons, including the overtaking aspect. We think racing is not improved by constantly increasing aerodynamic downforce, you need to have the right balance between mechanical grip, aerodynamic grip, horsepower, weight -- those sorts of things need to be in a certain territory to encourage close racing. If you allow the aero performance to get completely unbalanced then you reduce the spectacle."

Pressure on Pirelli

The case for upping downforce in 2017 is based on a plan to match the aerodynamic lap time gains with mechanical grip from the tyres. Pirelli has been given a mandate to produce wider tyres for 2017, automatically increasing grip, although the exact details are still being thrashed out with the FIA. One of Mercedes' main arguments against the 2017 regulations is based on concerns that Pirelli's tyres will not be able to cope with the extra load created by the new bodywork. The Italian tyre company has said it will produce whatever tyres the sport desires, but it is worth highlighting the technical challenge it faces with less than a year of development time remaining.

"The worrying bit is that as we add load and increase the duty placed on the tyre, which at the end of the day primarily has to remain within safe boundaries, the main way to manage that is to increase the pressure, and that's what Pirelli has already been doing even with the current tyres," Lowe says "As a result of various issues last year, we now run at pressures far higher than had been originally intended for these tyres in order to manage the loads.

"We have been generating around 10% more downforce every year across all the teams and we have seen that Pirelli have had to respond to that with pressure and the trouble is that when you put the pressure up you actually reduce the tyre performance. We are already a little bit in that window, but if you push it too far you end up in a position where responding to added downforce with pressure eliminates your net lap time improvement. There's a great risk that we go into 2017 with cars that are probably going to have 30 percent more downforce than today but won't go any quicker because the tyre pressures will have been increased so much to respond to that load.

"The other difficulty is that Pirelli, quite correctly, want a platform to test those tyres on the track. So they are asking us to build mule cars to test the tyres and that is a problem. How do you invent a test car that has 30 percent more downforce than the current car? We have never faced that problem in the past because we have always gone the other way with downforce, but it's actually very difficult because all the suspension is not rated to 30% extra load."

What next?

In 2014 the cars were deemed too slow for the top level of motorsport, and arguably they were, but since then downforce has increased and lap times have reduced by as much as 3.5s (based on Lewis Hamilton's record-breaking effort in qualifying in Bahrain). It is looking increasingly unlikely that significantly faster cars will provide the silver bullet the sport is seeking, while a lack of research into the side effects on overtaking has raised genuine concerns. Ultimately, Lowe thinks the sport needs direction both on its overall aims and how to achieve them.

"I think the important thing is always to have clear objectives and agree on those objectives up front before people settle into pre-defined solutions. That also needs to be done at a distance so it's not acted upon in self-interest, because naturally, as we get closer to a regulation change, the teams start to work in self-interest. I think when you don't put that together, that's when things start to go wrong.

"There is a duty upon the sport to put the work in to deciding what is wanted and what the proper objectives are. That in itself is a research programme to decide what we actually want and then to go and decide on how to do it. That's how we all work in our teams as businesses, we are very structured in our approach and that's how we deliver the lap time that we do. The sport needs to be a bit better at that as a whole in terms of its regulation development."