AlphaTauri began the season with the slowest car and ended it with the fifth fastest, as Yuki Tsunoda demonstrated in Abu Dhabi at the weekend by qualifying the AT04 in P6.

    It represented a great deal of hard work through the year in turning around the initially disappointing performance.

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    The initial weakness was in slow corner entry stability where a car’s ride height is at its greatest. The drivers were reporting this was limiting how much speed they could carry into the apex.

    The aerodynamic traits of the car meant the downforce was bleeding off disproportionately as the speed decreased and the ride height increased. In Abu Dhabi last weekend, McLaren Team Principal Andrea Stella remarked that according to their data, the fastest car through the slow corners was the AlphaTauri.

    BAHRAIN, BAHRAIN - MARCH 05: Yuki Tsunoda of Japan driving the (22) Scuderia AlphaTauri AT04 on
    The AlphaTuari (pictured here in the Bahrain Grand Prix) started the year as the slowest car

    This transformation wasn’t achieved with some revelatory development, but a constant series of wind tunnel developments targeting the car’s key weakness. It has centred around the underfloor – as that is where almost all the performance potential is within this set of regulations.

    Unfortunately we cannot see the underfloors unless a car is craned off the track, but these Giorgio Piola drawings (pictured below) show some of the changes which have been made in the floor edges and the fences around the tunnel inlets – and these are invariably just the visible manifestation of changes to the underfloor.

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    The fences determine how the airflow is split between that feeding through the tunnels which generate the low-pressure area beneath the car and that feeding outwards to the floor edges. The harder the vortices work along the floor edges, the greater the sealing effect for the underfloor.

    The optimised split between the two flows is what the aerodynamicists are chasing, but it’s more complex than just that. Because the behaviour of the airflow will change very significantly according to the car’s ride height – and that is constantly changing according to the speed of the car. That split can be optimised for high ride heights, or low, or anything in between.

    It became apparent as soon as the AT04 ran that the emphasis given in the car’s conception was wrong. That was at the root of the initially poor slow corner performance. As each new floor was made, so the team’s understanding increased.

    The first change to the floor came as early as race three, in Melbourne. We know that the flat ‘canoe’ section between the tunnels was reshaped, but only because the team informed us.

    The visible giveaways of that floor were the completely reshaped outer vane and the re-alignment of the inner vanes. It wasn’t a transformative update but it was the first step along that development journey.

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    A big step was taken with the introduction of another new floor at the British Grand Prix in July. The floor body, fences, floor edge geometry and diffuser were all new.

    The bodywork above the coke bottle section had been widened, giving “higher static pressure which reduces the extent to which front wheel wake losses impinge onto the bodywork with yaw and steer. This generates more load from the floor edge due to improved onset flow quality.”

    NORTHAMPTON, ENGLAND - JULY 09: Yuki Tsunoda of Japan driving the (22) Scuderia AlphaTauri AT04 on
    The AlphaTauri AT04 (seen here at Silverstone) had another new floor for the British Grand Prix

    Technical Director Jody Egginton confirmed that the Silverstone floor was a particularly vital building block and represented something of a breakthrough in their understanding.

    “Yes, that gave us a great new baseline and all the updates since were based on that base,” he says. “That was the one where we said 'yep, it’s delivering, this philosophy we’re following in the wind tunnel is working, we’ll keep pushing in this direction.'”

    The biggest visual change came at Singapore, with the lifted sidepods which allowed a more powerful vortex propagation as the airflow encountered the undercut at the front of the sidepod. This vortex would then be pulled down to the floor edges, boosting the flow which was being directed there from the vanes.

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    Another new floor came for Austin, and this update greatly enthused Yuki Tsunoda. At the next race, in Mexico, Daniel Ricciardo qualified the car on the second row, just 0.15s off Max Verstappen’s Red Bull.

    Finally for Abu Dhabi, yet another floor, this one featuring a re-alignment of the most outboard fence, done to better energise the floor edge wing, which had also been modified – with a pared-back forward part and widened rear. This was claimed to increase load directly on that part of the car.

    Jonathan Eddolls, trackside engineering chief, gave some background on getting the new floor to the final race as the team attempted to leapfrog Williams for seventh in the constructors championship.

    “We had found an interesting new direction in the tunnel a few weeks ago and we wanted to get the new parts made and on the car even though it was the last race of the season,” he said. “Just getting them made in time was an aggressive schedule and we have only two examples, one for each car, with no spare.

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    “Now we have this good slow corner performance but for next year we really need to address the car’s aero efficiency, because it is one of the slowest cars on the straight now. We need to re-address the balance between load and efficiency.”

    Development never stops, and F1 brains continue to find even more.

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