The car that began Mercedes' modern-era F1 success

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Mercedes’ dominance in Formula 1 has shown no signs of slowing down, as the W11 chassis helped the team to a seventh consecutive title double.

In fact, the W11 may go down in history as the fastest Formula 1 car of all time, thanks to a raft of new downforce-cutting regulations coming in to play this year, plus the new generation of cars arriving in 2022 which will be around three seconds per lap slower.

To understand just how Mercedes has got itself in to such a strong position, it’s important to delve into the team’s lineage of cars – and how the team has helped redefine the benchmark of a car/engine concept working perfectly in harmony.

The roots of the success that Lewis Hamilton and Valtteri Bottas delivered in 2020 were firmly planted when Mercedes unleashed its first turbo hybrid car, the W05, in 2014.

Mercedes’ first turbo-hybrid challenger

The W05 was supremely quick and reliable out of the blocks, which was the result of a coordinated and cohesive effort made by the team to get up to speed with the new turbo-hybrid rules that came in for 2014.

It was also immediate to see how well thought out the car was, as an unprecedented union of chassis, aerodynamics and powertrain departments allowed each facet of the car’s design to work in conjunction with the other. This is something that can be considered a cornerstone of Mercedes’ success throughout its reign.

At the heart of the W05 lay one of its greatest weapons – the PU106 power unit. This was a devastating piece of technology that would prove too potent for Mercedes’ rivals in the short term and would leave them playing catch up across the subsequent years.

The most eye-catching feature of the PU106 was undoubtedly the split turbocharger arrangement, in which the compressor was housed on one end of the engine, while the turbine was mounted on the other end.

This not only kept the hot and cold side of the turbo at arm’s length, but also allowed the MGU-H to occupy the space between them and the V-shape of the engine.

It’s a unique arrangement that was fraught with complications and can be considered an engineering feat in its own right. The design required a connecting shaft that stretches the entire length of the ICE, which must deal with the requisite rotational forces, rather than the minimum distance needed to incorporate the MGU-H should it be placed on the back end of the engine block.

However, Mercedes High Performance Powertrains (HPP) saw this as a challenge that would help in a wider sense, as it would allow them to repackage other aspects of the power unit too.

This knock-on effect inevitably led to more challenges though. For example, the size and shape of the compressor and turbine had to be reimagined in order they still fit within the confines of the box region they’d set aside for the entire power unit.

Having the compressor at the front of the engine would also mean that the oil tank would have to be redesigned. However, this would be offset by running a liquid-to-air ‘charge cooler’, rather than an air-to-air ‘intercooler’ arrangement.

The charge cooler being housed within a void above the fuel cell shortens the boost tract considerably, while a similarly sized radiator with the same core structure as the one used for the ICE is used in order that the sidepods weight distribution and aerodynamics are more evenly balanced.

This was aided further by some clever packaging from the Silver Arrows, with most of the internal components shaped to improve the airflow’s path through the sidepods, while also reducing heat transfer between each section.

Oddly enough, even though the Mercedes works team opted for this liquid-to-air charge air cooling method, the rest of the Mercedes powered teams used the more conventional intercooling solution and continue to do so to this day.

This picture also shows the mounting position of the ERS and gearbox oil coolers, mounted behind the power unit and fed cool air by the airbox inlets, of which Mercedes also had a pair of additional inlets on the side of the airbox.

A log-style exhaust manifold was used for the first iteration of power unit supplied by HPP in Brixworth. This configuration sacrificed some of the absolute top end performance that was available in favour of a much more compact design, once again showing how decisions were made to improve the car as a whole, rather than just taking the most aggressive route in each department.

No power without control

The Formula 1 power unit is an extremely complex piece of technology, with much more functionality than the V8 mild hybrid it superseded. As such, the drivers need to be able to have more information available to them and the ability to control many more functions.

Comparing the steering wheel from the W04 (left) with Hamilton’s W05 steering wheel, there’s a key difference in the overall shape along with the new PCU-8D display, which supplier McLaren had introduced to coincide with the arrival of the power units.

The LED display is much larger than its predecessor and offers 100 pages of fully customisable information, ensuring that the driver has all the necessary information at their fingertips.

The new display also opened up the possibility of having certain parameters in a graphical format that would otherwise have to be numerical on the older display.

Glancing quickly at the wheels you might be mistaken for thinking that both drivers had the same layout and design. But, in order to wring every last ounce of performance out of the car, the driver helped customise the base wheel design to suit their own needs.

This means that the functionality of some of the rotary switches will change, the function of the buttons will be in different locations and even the colour scheme of the stickers that outline each function will be altered to fit that driver’s requirements.

The paddles are also customised on the rear of the wheel, with Hamilton favouring a slimmer downshift paddle, while the angle and shape of the clutch paddles on both wheels were very different.

This comes down to the size of their hands and position on the wheel, with both favouring a different arrangement in order that they can use the various controls without having to move their hands around too much on the wheel.

Aerodynamic tricks

The W05 was not a one trick pony and although the power unit and the packaging from Mercedes clearly gave it an advantage over rivals, the car also combined more evolutionary design aspects with some interesting and unique aerodynamic solutions.

For example, at the front of the car, the team used a conjoined lower wishbone, narrowing the position between the two legs in order to turn it into one much larger aerodynamic fairing. This helped to keep the airflow coming off the front wing in the right position and further improved the performance of the surfaces downstream.

Meanwhile, the steering arm (red arrow) had also been repositioned and placed inline with the upper wishbone for better airflow management, reducing any distractions to the airflow as it made its way toward the sidepod inlet.

In an attempt to rule out the high nose solutions that had been favoured for their aerodynamic gains in the last few years, the FIA made changes to the nose regulations but, much like their rivals, Mercedes was dead set on keeping the nose as high as possible.

Its solution was probably one of the most successful workarounds, with an inverted U-shaped nose tip deployed that fulfilled the dimensional criteria inserted in the regulations in a display of lateral thinking.

This opened up the necessary channel for the airflow to make its way under the nose and was improved upon during the season, requiring additional crash tests to be passed in order to prove that the nose would perform as expected in an accident even with the more complex shape.

If we consider that aerodynamics act like a daisy chain, with each surface or solution having an impact on the next in line, it’s no surprise that Mercedes would also develop the ‘turning vane’ section of the car.

For 2014, having already started to move in this direction in 2013, Mercedes moved its turning vane assembly forward, using two prongs on the W05 that extended out from the front of the chassis and mated with the underside of the nose.

This was a clever way of shifting the vanes into a more forward position and allowed them to act on the airflow earlier.

As a consequence of the developments that the team made with the nose, more changes were made to vanes later in the season too. In order to facilitate an extra vertical element, taking the count from 3 to 4, the prongs also had to be altered as a consequence.

To reinforce these changes and take advantage of the space behind the turning vanes, the team added a new link in the chain, introducing its ‘Bat-Wing’.

Riding the ride height sensor, the wing altered the airflow’s flow direction further still, improving the link between one section of the car with the other.

It would also evolve over time, with a revised mounting connecting it to the underside of the chassis, while a slot was added to the winglet ahead of it too.

At the back

The rear of the car was just as well thought out too, embracing the shift from a twin exhaust outlet arrangement that had spawned the various blown diffuser solutions during the V8 era, with a single exhaust outlet that had to be placed centrally.

But, never one to miss out on an opportunity to leverage an aerodynamic advantage from the exhaust gases, all of the teams ran winglet or monkey seat solutions that worked in conjunction with the given aerodynamic package.

This was another area where Mercedes had been particularly diligent, with numerous rear wing and monkey seat combinations deployed throughout the season depending on the load demands of the circuit being visited.

No matter the configuration, the rear wing employed a twin mounting pillar arrangement, adding stability in lieu of the beam wing that had been removed under the new regulations.

Meanwhile, the endplates featured surface contouring to promote a route for the airflow through the various slots that perforated the surface, and are shaped to influence an upwash effect in order that the flow structures at the rear of the car remain as connected as possible.

Each circuit requires a different aerodynamic configuration due to the effect the blend of corners and straights have on the overall performance envelope of the car. These three illustrations highlight the differences between a low, medium and high downforce setup, with various nuances available between each to cater for the given circuit.

In the above image, the car has a high downforce configuration with a deep box region with a suitably sized mainplane and top flap, while a Gurney flap is fitted to the trailing edge to improve downforce and balance at the consequence of inducing some additional drag. Meanwhile, a complex monkey seat arrangement is used to influence the direction of the exhaust plume.

A mid to low downforce arrangement had the Gurney flap removed from its usual configuration removed to strip some drag off. In that respect the outer corners of the upper flap had also been trimmed back to alter the potency of the tip vortex, while a more simplified monkey seat is deployed.

The low downforce rear wing used at Monza features a smaller box region for the mainplane and upper flap, while the pillars also have a different shape where they connect to the mainplane. This is important in order that the airflow isn’t adversely affected by the pillars due to the reduction in surface area for the flaps.

Suspension developments

Seen here fitted to the W04, but also found on the W05, was the FRIC system, a hydraulic system that connected the front and rear suspension and allowed for more control over the car’s platform.

It’s a system that all of the teams had in one form or another but it was Mercedes who was considered to have the most advanced version – which is why rivals set about trying to get some clarification over its legality.

The FIA had been convinced that, while the original intent of the system had been to improve suspension compliance, as the teams developed the system the focus had switched to how that could impact the car’s aerodynamic platform.

At the British GP, it announced that the system would be banned from 2015. However, with the admission that the FIA technically now considered the system illegal, it meant that a post-race protest could result in any points accrued being taken away.

As a consequence all of the teams agreed to remove their systems with immediate effect, with Mercedes expected to struggle the most without it. However, it did not.

Mercedes went on to take 16 victories in a 19 race season that saw both drivers push the car, themselves and the team to their limits.

The advantage that the W05 had over the rest of the field was apparent, and this translated into the most dominant lineage of cars in the sport’s history as it paved the way for the equally brilliant W06 and W07 cars.

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