15/05/2013
FEATURE BY MATT SOMERFIELD
The Spanish Grand Prix at the Circuit de Catalunya heralds the first pivotal point in the season, the return to Europe seen by the teams as the first opportunity to roll out larger upgrade packages. Let's take the opportunity to look through some of the upgrades applied by the teams.
Red Bull
A critical area this season is the area around the rear tyres. The change of construction by Pirelli to its 2013 tyres means the sidewalls deform under load which in turn impacts on the aerodynamics. 'Tyre squirt' is when airflow is deflected off the rotating wheel/tyre and pushed laterally into the diffuser's path. This is why the teams are so eager to target the exhaust plume in the gap between the tyre and the floor as it blocks the effects of 'tyre squirt'. The problem comes with the transition between on and off throttle, as the driver lifts out of the throttle and the exhaust plume dissipates once again 'tyre squirt' begins to play its role destabilizing the diffuser's natural airflow.
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The addition of floor strakes and slots ahead of the rear wheels by the teams has become common place since the teams started utilising 'Coanda' exhausts. These help to manage the airflow coming around the sidepod, repurposing it, creating vortices that manage the wheel’s airflow pattern reducing the effects of 'tyre squirt'.
Over the last few races I have mentioned Red Bull's adoption of a secondary vertical floor strake ahead of the rear tyre in order to help with this problem but before qualifying in Barcelona the team also revised the area with a 'tyre squirt' slot. The team hasn't raced a solution like this since Monaco last year where it came under scrutiny for placing a hole in the location rather than a slot.
Lotus
Having already subjected the E21 to revisions throughout the fly away races the Enstone team made much smaller alterations for Barcelona:
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The new front wing features two new elements, the vane drooping off the endplate (Yellow) will undoubtedly generate a vortex aiding in extracting airflow outbound of the front wheel. Meanwhile the inbound deflector (Red) has been perforated allowing the element to work more effectively in yaw.
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The Rear Wing on the E21 has had vanes positioned on the sides since the start of the season but in Barcelona the team separated them again I'd presume to make them more efficient in yaw.
Ferrari
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Ferrari had perhaps one of the largest visual upgrade packages available for Barcelona (top of the comparison image above). However, with time lost in FP1 due to the weather and the package only applied to Massa's car the team decided to abandon it for the weekend. We can see that the team revised its twin element sidepod airflow conditioners, the forward section curving up over the sidepod acting as a leading edge slat as it meets with the cockpit. The rearward section of the airflow conditioner meets with the shoulder of the sidepod and aids in the direction of airflow along the side of the sidepod. The bodywork rearward of this was also altered allowing the exhaust channel to be moved rearward altering the position the exhaust plume lands on the floor of the car. Furthermore, the bodywork allowed a much deeper undercut at the rear of the sidepod migrating more airflow into the ‘Coke bottle’ region.
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Perhaps added to aid in the new package (not raced as above) a new fin was placed ahead of the mirror on both Ferraris.
Mercedes
Mercedes has made a priority of extending the life of its tyres for the forthcoming races with the team still struggling with degradation relative to its counterparts.
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Having adopted the 'Coanda' exhaust this season the team opted to run with an aggressive Sidepod AoA and vorticise the airflow received over the sidepod by three cockpit fins. This gives a much wider operating window and makes the results of the 'Coanda' effect and downwash over the sidepod less to speed. For Barcelona the team opted to reduce these fins to a singular element which is much larger and has a deltoid shape.
Meanwhile further downstream the team has shrunk the engine cover reducing both the size of the cooling outlet and the fin on top of the cover.
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Internally a shot of the floor off the car shows the team has also added another tier to the section under the crash structure.
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McLaren
It doesn't really need repeating but McLaren is having a terrible start to its 2013 campaign and had hoped that revisions bought to Barcelona would put it back in the hunt. The problem however is that whilst it needs a monumental step in order to bring it back to the fore, those ahead are making incremental steps that are taking them further away.
The items the team tested and continued to use for the race were all aimed at modifying the effects seen at the rear of the car and how the exhaust interacts with the floor/diffuser.
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The sidepod airflow conditioners were redesigned in order to curve over and meet with the shoulder of the sidepod, much like we have seen teams do up and down the paddock, meanwhile above the sidepod's inlet the team returned to the use of two vertical vortex generators. Both the airflow conditioners and vortex generators are installed here to trim the airflow being dispatched towards the exhaust. The vortex generators energise the airflow that moves over the sidepod, reducing the boundary layer formed by slow moving air thus making the sidepod work over a larger range.
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The rear wing was treated to a hole in the leading edge of the endplate which allows airflow to move inbound reducing the effect the tyre has on the airflow in that region. It's a trick we have already seen Williams, Force India, Toro Rosso and Marussia implement.
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The team also revised the lower elements/fins in the rear brake duct assembly attenuating the airflow and exhaust plumes influence in that region.
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Sauber has struggled to maintain the performance it had during 2012 and like McLaren is struggling to rectify deficiencies in the design around the rear of the car (due to the nature of this year tyres) enabling them to extract performance from the diffuser. Part of this process starts at the front of the car and for Barcelona we find the team has moved the FOM cameras into the Hammerhead position at the front of the nose. This takes them out of the area behind the mandated central portion of the Front Wing an area used by some teams to set up the onward airflow to the diffuser.
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Since pre-season testing Sauber has run with an unconventional mainplane in its rear Wing which looks to encourage more downforce for less drag, having tested a more conventional design in Bahrain, the team arrived in Barcelona with a revised setup.
Toro Rosso
The sister team to Red Bull, Toro Rosso always tend to get missed by the media but its upgrade for Barcelona certainly didn’t pass me by. Reminiscent of the ideas used by Red Bull, the Faenza team brought a new exhaust package that sees it utilizing a cross-under tunnel.
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Toro Rosso is the first non Renault team to take this approach and although it differs in many ways to its sister team the inherent qualities of the design carries over.
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The Toro Rosso version holds a resemblance to the original version Red Bull tried in 2012 with the airflow exiting just aft of the exhaust channel, aiding in both the exhaust plume’s target direction and the flow into the ‘Coke bottle’, rather than Red Bull which encloses the airflow to exits under the engine cooling exit. The differences encountered by the two teams in their approach can be largely put down to engine characteristics, engine mapping and using (Red Bull) or not using (Toro Rosso) enclosed halfshafts.
Caterham
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Caterham ran with a heavily modified CT-03 in Bahrain which I covered in my post race analysis but the team continued to push forward in Barcelona running with a new front wing and vanity panel.
Note: All pictures can be found in higher resolution here.