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How the downwash solution ended up winning F1's sidepod war

Formula 1's new technical regulations for 2022 left many fearing the end of design variance and a grand prix grid full of identikit cars.

Red Bull Racing RB18 sidepods detail

Giorgio Piola's F1 technical analysis

Giorgio Piola is the preeminent Formula 1 technical journalist. View our full selection of Giorgio's technical illustrative content

However, despite some clearly more prescriptive regulations, there were distinct differences between each machine, with the sidepods, in particular, offering a wide variety of design solutions.

Now, a year and a half into this regulatory era, we have started to see a wholesale shift towards one of these concepts – the downwash solution - as teams realise it best serves the overall aerodynamic needs of the current rules.

Alpine, AlphaTauri and Red Bull were the first to adopt this solution, and of these Alpine was the first to take its own unique development pathway, with the team making changes to its inlet design as early as the 2022 Azerbaijan Grand Prix in preparation for it.

Alpine A522 side floor detail
Alpine A522 sidepods detail

The waterslide, gulley, or whatever terminology one might use to describe it, takes advantage of the fact that the bulk of the sidepod bodywork that's being used under these new regulations is a facade, with the designers able to more tightly shrink-wrap the bodywork to the components, as they did under the previous regulations.

Alpine realised that with its aerodynamic objectives being met by the front portion of the sidepod, it could make better use of the upper bodywork of the sidepod to feed the airflow into the desired locations downstream.

And, while it can clearly take credit for this new branch of development, it also likely took some inspiration from Ferrari's bathtub-like solution.

Ferrari F1-75 side pods
Ferrari F1-75 sidepods comparison

Much like the downwash ramp solution, the sidepod bodywork employed by Ferrari is wider than what's needed to envelop the internal components, with much of that bodywork engaged in reconditioning the turbulent airflow created upstream of it.

The bathtub's scalloped upper surfaces worked in conjunction with a series of cooling gills that the regulations permitted, once again, with the rear cooling outlets reduced in size as a consequence.

Ferrari did make some changes to the layout during 2022, albeit these were topographic optimisations, rather than a wide sweeping conceptual shift.

Aston Martin front comparison
Aston Martin AMR22 new layout

Aston Martin and Williams were the first to break rank in 2022 and switched from their respective high-waisted and short-ramp solutions to ones more closely aligned with the philosophy employed by the downwash trio.

The main switch came at the Spanish Grand Prix for Aston Martin, as it made a diligent attempt to replicate the RB18's floor and sidepod solution, albeit held back by the sidepod's inlet design, with the upper SIP obstructing a shift to the open-top solution championed by Red Bull.

Williams FW44 floor cut
Williams FW44 open vs closed sidepod

Meanwhile, Williams was one of the teams to have a design identity of its own when the season first began, with a novel approach taken by the team from Grove that included a bypass duct on the upper shoulder of the sidepod.

The team had designed the solution in such a way that when the duct was open it would help feed airflow down its shortened ramp to the floor behind, but it could also close the duct off too, increasing cooling capacity.

Williams FW44 side view comparison2

Williams FW44 side view comparison2

Photo by: Giorgio Piola

Williams clearly realised quite early on that its concept wasn't going to provide the kind of performance it was looking for, but couldn't implement its own version of the longer downwash ramp until Silverstone.

Suitable changes were then also made to its floor and engine cover in order that they contributed in unison to an uplift in performance.

The other major outlier in terms of its sidepod design was Mercedes, with the team having originally presented a more vanilla arrangement at its 2022 launch, which it subsequently used at a shakedown at Barcelona.

Mercedes W13 side view comparison

Mercedes W13 side view comparison

Photo by: Giorgio Piola

The teams moved to the official pre-season test in Bahrain, where Mercedes unveiled its new solution, which would quickly be dubbed the zeropod.

The zeropod represented a stark contrast to many of the other solutions that had been presented by its rivals, with just a slender vertical inlet projecting out from the side of the W13's chassis, which was responsible for cooling its internals.

The rest of the bodywork clung tightly to the components housed within, in much the same way all teams had proceeded to shrink-wrap their bodywork under the guise of the previous regulatory era.

In order to achieve its zeropod goals, the team did have to think a little laterally when it came to the upper SIS, which was housed in its own fairing both forward and above the main bodywork.

MCL36 side view comparison
McLaren sidepods details

McLaren, like many of its rivals, started the season with its own concept but drifted towards something more akin to the downwash ramp solution seen on the Alpine, AlphaTauri and Red Bull. It was able to inject more of the latter team's DNA into its design, as it also appropriated a similar inlet design.

This 'underbite' solution for the inlet was fully incorporated in McLaren's design language for 2022, with the team conducting a full makeover of the sidepods, floor and engine cover at the Austrian Grand Prix and setting the scene for what has been a significant leap up the competitive order for the team.

McLaren side comparison (Silverstone endplate Inset)

McLaren side comparison (Silverstone endplate Inset)

Photo by: Giorgio Piola

It's clear to see that barely a surface has been left untouched in the car's revamp, with the underbite and inlet, undercut, flank geometry and length of the sidepod's downwash ramp also increased. And, following in the footsteps of Aston Martin, McLaren has also incorporated a much deeper water slide on the upper surface of the MCL60's sidepods.

The deeper water slide solution is a prime example of how F1 teams take an idea and then move the needle when incorporating it themselves.

The AMR23's design, for example, has its roots in the shallower version first seen on the Alpine A522 in 2022, which has since spurred several new development ideas, including Aston Martin, which has since taken its design a step further, with an update it introduced in Canada.

Aston Martin AMR23 sidepods view

Aston Martin AMR23 sidepods view

Photo by: Giorgio Piola

Meanwhile, Ferrari has now also incorporated its own version of the water slide feature, albeit a shallower variant, as it made the first steps towards more of a downwash ramp solution when it updated its sidepods at the Spanish Grand Prix.

The changes also resulted in the team having to revamp its cooling gill arrangement, with much of the responsibility for that housed on the shoulder of the engine cover, although it does still have the option to add or reduce cooling via the interchangeable panels housed within the bodywork.

It retained its 'S' duct arrangement as part of the update, with the solution baked into the overall philosophy of its sidepod, given the vertical inlet beside the chassis is used to transport airflow from beneath the main inlet and deliver it out over the upper surface of the sidepod via the curved outlet beside the halo.

Ferrari SF-23 comparison Spanish GP
Ferrari SF-23 S-duct detail

Mercedes' reluctance to accept that the zeropod concept was flawed, and continuing with it for the start of 2023, resulted in the team having to take even more of a Frakenpod approach when it did finally make the switch at the Monaco Grand Prix.

This is due to the aforementioned SIS fairing's location, as it can't be changed without introducing a new chassis. This also compromises the design of the inlet, the undercut and the upper bodywork of the sidepod based on solutions seen elsewhere.

The Monaco update also turned out to be an interim solution, as the team optimised both the inlet, the rest of the sidepod bodywork and its floor at the Belgian Grand Prix.

And, while it is still clearly able to squeeze more performance out of its new design, it will more than likely take a very different approach to this area of the car next season.

Mercedes W14 sidepods detail, Belgian GP

Mercedes W14 sidepods detail, Belgian GP

Photo by: Giorgio Piola

Red Bull is currently the tip of the spear and so it's no wonder that the downwash ramp solution is often attributed to it, even though others also started their 2022 campaign with similar solutions.

And, while those in chasing pack have experimented with waterslide-style solutions, Red Bull has held its nerve thus far, as it continues to employ a more benign ramp in its bodywork down to the rear of their floor.

However, where it hasn't held back is in its decision to improve the forward portion of the sidepod, with a significant emphasis placed on the RB19's inlet and how that can influence the size of the undercut.

This journey began in Azerbaijan when the height of the inlet was reduced but widened to compensate. This was followed up with a more significant update at the Hungarian Grand Prix, as the team made changes to the sidepod's internal components and ducting, while optimising the external bodywork for further aerodynamic gains.

The updates centred around the inlet and underbite scoop, as the latter was extended forward, making the inlet look even smaller from certain angles. The added benefit is this enlarges the undercut while protecting the inlet from the errant and turbulent wake being cast from the car's front end.

Red Bull Racing RB19 sidepods inlet comparison
Red Bull Racing RB19 sidepod detail

It's clear that there's now one main development route that the teams are taking but that's not to say that they're all doing the same thing. In fact, it's far from it and it will be interesting to see which of these competing solutions teams choose going forward and if there are more offshoots from the main development tree.

History repeating itself

The prevailing regulations tend to guide teams down certain design paths but more often than not they will find different answers to the same questions.

The visual discrepancies seen in each of the aforementioned sidepod solutions are obviously intriguing but it's obviously not the first or last time we'll see such an occurrence, with perhaps the most obvious example in the recent past coming in the 2012 and 2013 seasons.

F1 had already gone through the exhaust blown diffuser phase in 2010 and 2011, and the FIA was keen to eradicate the effect with a change in the regulations that would prevent the exhaust from being flattened and housed on top of the floor and the exhaust gases used to help drive the diffuser's performance.

However, while the governing body made numerous changes to the exhaust and bodywork regulations to try and ensure that the exhaust wouldn't be as influential, the teams had other ideas and set about using the surrounding bodywork to create an aerodynamic replacement for those physical components.

Initially, there were four or five solutions that teams had found independently of one another on the lead-up to 2012 but, as you'd expect and just as is happening today, they all started to converge on the ideas that offered the most promise.

Mercedes W03 top view, yellow arrows depict predicted trajectory of the exhaust plume

Mercedes W03 top view, yellow arrows depict predicted trajectory of the exhaust plume

Photo by: Giorgio Piola

The periscope style design was more in keeping with the solution that the FIA expected when it introduced the regulations, with several teams, including Mercedes, shown here, employing it from the outset.

Lotus E20 periscope style exhausts

Lotus E20 periscope style exhausts

Photo by: Giorgio Piola

The E20 sported Lotus' initial periscope style exhaust solution too, with the hooded bodywork around the exhaust expected to help influence the exhaust plume.

Red Bull RB8 original exhaust solution exiting under upper wishbone, arrows depict predicted exhaust plume trajectory

Red Bull RB8 original exhaust solution exiting under upper wishbone, arrows depict predicted exhaust plume trajectory

Photo by: Giorgio Piola

Red Bull also signalled its intent to use a periscope-style solution when the car was unveiled.

Red Bull RB8 'Coanda' exhaust ramp solution, blue arrow shows how air should travel under the ramp, yellow arrows show projected exhaust plume trajectory

Red Bull RB8 'Coanda' exhaust ramp solution, blue arrow shows how air should travel under the ramp, yellow arrows show projected exhaust plume trajectory

Photo by: Giorgio Piola

It quickly became apparent that Red Bull had other ideas though, as a much more complicated solution arrived, which had a ramped rear section for the sidepod, in which the exhaust was housed. It clearly hoped that by pairing the exhaust plume with the airflow from over the sidepod bodywork it would find its way towards the area targeted by the outgoing blown diffusers.

To add further complexity to its solution, Red Bull also had a tunnel in the sidewall of the ramped sidepod bodywork that aimed to flow out into the Coke bottle region.

McLaren MP4-27 semi 'Coanda' exhaust solution, gills added in front of rear suspension to reject heat

McLaren MP4-27 semi 'Coanda' exhaust solution, gills added in front of rear suspension to reject heat

Photo by: Giorgio Piola

A competing solution that seemed to offer a similar trajectory for the exhaust plume, albeit without the bodywork in the lower half was McLaren's semi-Coanda arrangement.

Ferrari F2012 'Acer duct' style exhaust configurations at the start of the season

Ferrari F2012 'Acer duct' style exhaust configurations at the start of the season

Photo by: Giorgio Piola

Ferrari had its own solution, dubbed the Acer duct, owing to the sponsorship placement on the bodywork. The team tried various iterations for the exhaust placements within the bodywork to release the performance it was looking for.

Red Bull RB8 'Coanda' exhaust ramp comparison

Red Bull RB8 'Coanda' exhaust ramp comparison

Photo by: Giorgio Piola

Red Bull continued to iterate with its design too, with changes in this instance coming to the exhaust trough to try to further influence not only the plume's direction but also how it engaged with the airflow entering the crossunder tunnel below.

Red Bull RB8 exhaust solution change (older specification inset)

Red Bull RB8 exhaust solution change (older specification inset)

Photo by: Giorgio Piola

The solution continued to evolve, with the shape of the bodywork around the exhaust, the ramp length, the shape and frequency of inlets housed within the crossunder tunnel and their exit point all altered on what seemed like a race-by-race basis.

Red Bull RB8 enlarged crossover tunnels (see inset for comparison)

Red Bull RB8 enlarged crossover tunnels (see inset for comparison)

Photo by: Giorgio Piola

Another angle shows the lengthening of the cross-under tunnels and the ramp section. Also, note the three dividers placed beneath the driveshaft fairing to help influence the airflow's trajectory over the top of the diffuser.

Mercedes W03 Semi-Coanda exhaust, predicted path of exhaust plume arrowed

Mercedes W03 Semi-Coanda exhaust, predicted path of exhaust plume arrowed

Photo by: Giorgio Piola

Teams started to make the switch to other solutions during the course of the season, as they eyed a more productive version for the following season, with Mercedes one of the teams making the switch to the semi-Coanda solution.

 

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