Sergio Perez’s Monaco accidents two years in succession have given everyone a great opportunity to compare a feature of the Red Bull cars believed to be at the heart of their aerodynamic superiority: the underfloor.

    What is clear looking at the floor of the current RB19 (see drawings below) is that it is a further developed version of last year’s floor, which in itself was far more sophisticated than those of the competition.

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    When the current ‘ground effect’ regulations were introduced last year, other teams all featured low-roofed tunnels, maximising the theoretical air pressure difference between the underfloor and the ambient air above.

    The flat underbody section separating the left and right-sided tunnels was generally of a teardrop shape, and because of this came to be labelled the ‘canoe’. The contours of the sides of this area of flat floor (onto which the regulation plank is mounted) defined the lateral width of the tunnels along their length.

    Last year’s Red Bull floor was not like that at all. Its high-roofed arched tunnels were quite different to the square-cornered, lower roofs of rival cars. Furthermore, the central section of flat floor was not teardrop or canoe-like in shape but quite angular, with distinct sudden profile changes along its length.

    Perez’s qualifying crash in Monaco gave rival teams a closer look at Red Bull’s floor design

    A higher roofed tunnel, such as that of the Red Bull, would not in theory generate as much suction effect as the low-roofed tunnels of the others. However, it allowed the underfloor to be much more resistant to the airflow stalling as the floor came in close proximity with the ground.

    Furthermore, the profile of the ‘canoe’ section, with its relatively thin and straight forward section, created a much bigger volume for the air to fill before the tunnel narrowed further back.

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    There’s a trade-off to be made in the volume of air feeding the tunnels and how fast it can be made to flow, and that trade-off was visibly quite different on the Red Bull. The downforce generated will generally be a multiple of the airflow’s volume and speed.

    What this geometry seemed to allow Red Bull to do was create a car with relatively soft suspension. This allows a better compromise between low and high-speed corners than the stiffer suspensions the competition was obliged to run to keep their underbodies from stalling.

    Lewis Hamilton was another to crash on the streets of Monte Carlo, revealing the details of Mercedes’ floor. The upgraded W14 features a more Red Bull-like ‘canoe’ central section than it had last year, but evidently still without the intricate sophistication of the current Red Bull floor

    All the cars are pressed down on their suspension by the downforce (which generally squares with speed). But a car with softer suspension, such as the Red Bull, can be pressed down lower at high speed.

    The effect of this is that, even though its tunnels have higher roofs than the others, at speed – because the Red Bull is being pressed down further – the Red Bull tunnel roofs are actually just as close to the ground as on conventional lower-roofed tunnels, and thus generating plenty of downforce at high speed. So, the Red Bull ran a high tunnel roof with a low ride height while the others ran the opposite.

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    The conventional cars, with lower roofed tunnels and stiffer suspensions, cannot run as low a ride height without inducing bouncing. Further enabling Red Bull to run a lower ride height than the others was the extreme anti-dive geometry of the front suspension. With less dive and pitch to account for, their car can be run lower.

    The greater volume of the high roof also allowed the tunnel’s inlet section further forward its generous dimensions, which in turn would make the whole airflow more stall-resistant, capable of handling a lot of air volume.

    Some of those features have been copied by the competition – the more square-cut ‘canoe’ sections have generally replaced the former teardrop shapes, for example. But Red Bull have continued to progress the sophistication of their design.

    Left to right: Red Bull’s 2022 floor (without plank), showing how the central flat section of floor already contrasted with the conventional teardrop; Red Bull’s 2023 floor, with various changes highlighted (see explanation below)

    When comparing the current car’s floor to that of last year’s, it has retained the square-cut canoe section (1), but the lines are subtly different. The outer vanes around the inlet (2) which direct airflow to the outside – helping seal the floor and speed up the airflow down the sides of the car – are now angled for a greater degree of outwash.

    The high arched roof (3) is retained in the forward part of the tunnel but now transitions into an upwards ramp (4) to form an initial kick-up point prior to the main one further back which forms the diffuser ramp.

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    This ‘double kick’ is not a Red Bull innovation but helps energise the airflow, manipulating the air pressure to speed up the flow as the air rushes to fill the lower pressure areas.

    The outer edges at the rear of the floor (5) are much more complex than before, with extra channels around the diffuser. This is quite possibly in compensation for the raising of the rear floor edge and diffuser introduced into the ’23 regulations.

    Overall, it’s still a more sophisticated-looking floor than those of other cars and appears to employ the same philosophy of inducing a wide spread of usable, controlled downforce. The addition of a more extreme anti-squat rear suspension has combined with the extreme anti-dive front to give even better control of the platform of the car, so further enhancing its ability to run low.

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