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After a dominant start to Formula 1’s turbo-hybrid era, with Mercedes getting ever stronger, it was inevitable that at some point it would hit its first bump in the road.

That moment came in 2017 with a W08 that, while still successful, delivered some headaches for its designers and drivers, and quickly earned a reputation as ‘a bit of a diva’.

That such a challenge arrived that year was hardly a surprise though, as F1 had moved that season to shake up the regulations in a bid to increase the speeds of the cars – and that meant a change in aerodynamic formula for all teams.

The headline changes were an increase in the car’s width from 1.8m to 2m. There was also a delta-shaped front wing, a diagonal leading edge to the floor, more design freedom for the bargeboard region, a larger diffuser volume and a wider, lower, swept-back rear wing assembly.

As usual, there were several unforeseen consequences of the regulation changes that would also crop up, with the likes of shark fins and T-wings returning.

Mercedes not only pounced on these opportunities, but also took advantage of the change in regulations to use the shark fin as a way of keeping its car cool when needed. It achieved this with an outlet on the top of the engine cover that could expel heat created by the power unit and its ancillaries, and the outlet was adjustable depending on the demands of each circuit.

Meanwhile, its double loop T-wing was housed on its own mounting pillar which, like the rear wing pillar, intersected the exhaust to find a mounting point on top of the crash structure.

The angular changes within the regulations, which were envisaged as a way of improving the aesthetic, meant that the cars would lengthen. The nose had been extended by over 200mm while the rear wing would also lean back further than in 2016.

The alterations to the front of the sidepods and the leading edge of the floor, including the inclusion of an upturn, also prompted many to rethink the entire aerodynamic map of the car.

This is of particular interest when we consider the interaction between the floor, now 200mm wider and the diffuser, the volume of which had been increased significantly.

To combat this, Mercedes revised the W08’s wheelbase, adding approximately 200mm between the front and rear axles. Part of that motivation for this was in attempting to soften the aerodynamic blows that the new rules had on its low rake philosophy.

Meanwhile, their front suspension was also revised, as the team raised the upper wishbone by means of an upright extension, in order to alter both the aerodynamic and mechanical characteristics of the car.

Perhaps the most critical hammer blow that Mercedes would sustain came just before the season was due to get underway though, as the FIA issued a technical directive regarding suspension systems and its role in aerodynamics.

As already discussed in the first of this series of articles, front-and-rear interconnected suspension (FRIC) had been banned from 2015 onwards, but that didn’t mean teams gave up on that knowledge.

The directive, issued in response to questions raised by Ferrari, was thought to take aim at the systems and development direction that Mercedes and Red Bull had taken, with both likely hamstrung by it, handing Ferrari a small advantage in the process.

Development diary

The introduction of new rules always results in a more intense development race, and 2017 was no exception. As usual, all of the teams went off in their own direction prior to seeing each other’s cars but, as the season got underway, it was clear we were going to see the teams converge on what were perceived to be the best solutions.

Despite this and catering for the aerodynamic connection between the front and the midsection of the car, Mercedes introduced a new concept at the Spanish GP. Flanking the main body of the now-narrower nose, which tapered in more dramatically at the bulkhead mounting point, its ‘cape’ solution was effectively a much larger set of turning vanes that would influence the airflow much earlier in its lifecycle.

It made several changes to its cape during the season, optimising the design to ensure it performed as expected and worked in harmony with the other changes that were being made to the W08.

The concept is now a staple on the F1 grid, with almost every team running or having run a design variation of it.

The area of the car that would offer the most low-hanging fruit, owing to the regulation change, would undoubtedly be the area ahead of the sidepods.

The designers were able to find more performance from the bargeboards and the leading edge of the floor, while there was now an ability to use fully enclosed holes on the outer perimeter of the floor thanks to the width change mandated by the rules.

The W08 underwent several changes in this respect throughout the season, with the aerodynamic furniture surrounding the main bargeboard element changed frequently in an effort to unlock additional performance.

Meanwhile, the front portion of the floor upon which the sidepod deflectors were mounted (blue arrow), was also tuned inline with slots added into the floor behind them.

The team also continued to develop downforce configurations for the circuits it would visit, such as the customary low-downforce rear wing. The shark fin was extended several times during the season, with an update in Singapore that finally meant that it met with the T-Wing pillar, increasing stiffness and adding some additional surface area for increased side force.

All of these changes came against the backdrop of Mercedes struggling with the balance of its car and, perhaps more importantly, the inability to get the tyres to work as anticipated.

After plenty of head-scratching back at Brackley, the team began to build a clearer picture of what was needed to overcome its issues, with the car clearly worse at lower speed circuits or in warmer conditions.

The issues, which narrowed its setup window more than it would have liked, revolved around the tyres, with the rears giving it the most trouble. It’s a battle that all of the teams face each and every year, with performance and durability offset front-to-rear through setup changes at the given circuit.

Mercedes initially found this difficult, as it simply didn’t have the headroom to make the setup changes it needed. This forced the tyres outside of their given temperature threshold and made life difficult for their driver pairing. It was this characteristic that earned it the ‘diva’ nickname.

However, as the season wore on, Mercedes developed its way out of the corner, making life easier for the drivers and easing concerns that its 2018 challenger could be compromised in similar ways too.

This is not to say there weren’t some nagging doubts when the W09 shook down for the first time, especially as the team knew it needed to be on top form given the advancement that its rivals had been making too.

Evolving into the W09

The team avoided going for a revolutionary approach, and instead it would look at ways to evolve the concept that had served it well up until now, when yet another regulation change was also on the horizon.

On top of this, all of the teams had to deal with a new arrival: the halo. The safety device not only added weight, but also had a structural impact on the design of the monocoque. Meanwhile, its presence would also result in aerodynamic complications that all of the teams would have to overcome, with only a small fairing available to help offset the issues that it had created.

Mercedes not only used the fairing to redirect the disturbed airflow over the rest of the car, but it also took advantage of the halo’s installation to create a cooling aperture where others simply blended it into the bodywork.

This reduced the reliance that the team would have on the cooling panels usually found on top of the sidepod next to the cockpit, and it also altered how the airflow behaved as it spilled off the back of the halo.

The introduction of the raised upper wishbone arrangement in 2017 was followed by further developments in that region on the W09. The team made changes to the winglets mounted on the brake fence to better manage the airflow, while an entirely new winglet was rolled out at the Canadian GP (right).

Interestingly this was an idea from the Sauber stable, a team which had moved to the higher wishbone mounting for 2018, proving that Mercedes studied the designs of its rivals no matter their position in the standings (inset).

To help alleviate the issues that the team had during 2017, the team made changes to its rear suspension with the W09’s upper wishbone raised at the outboard end. This was achieved with an upright extension, much like the team had done at the front of the car just a year earlier and would offer them much more flexibility in terms of their setup.

Meanwhile, having constantly struggled with tyre temperatures during its previous campaign, the team expended a serious amount of resource on rectifying that issue with its wheel rim design.

Outwardly this initially looked like it had been resolved by adding large fins to the face of the rim, which act like a heatsink – altering the temperature distribution to the wheel and tyre.

As the season unfolded, it became apparent that Mercedes had another trick up its sleeve too with a very clever solution that required one design aspect to lean on the other. The upshot of this would mean that airflow taken in by the rear brake duct inlet could be funnelled through the wheel rim to help manage the core temperature of the tyre.

As we can see from the illustrations, the holes in the brake bell (right) would align with the small holes in the mounting face of the wheel (left) and allow airflow captured by the brake duct inlet a route through the assembly to the wheel’s mating face.

This air would move through the hollow cavities within the wheel and help to cool the core temperature of the tyre. Hot air is then drawn out through the central holes (red arrows) and passed out through the wheel itself.

The W09 took 11 victories during 2018, all at the hands of Lewis Hamilton, who once again reigned supreme, securing his fifth drivers’ title. Ferrari ran the team much closer in the race for the constructors’ title – but still fell short of toppling the Silver Arrows.

In the next instalment we’ll focus our attention on the W10, as Formula 1 embraced yet another rule change that could upset the competitive order.



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