Looking at the AT04, the first thing we notice is the use of pushrod suspension at the rear, where last year's car used pullrod suspension.
This change is easy to explain. Last year, the Faenza outfit decided not to use the transmission and suspension package from Red Bull Technologies. Instead, they designed and built their own rear end, with suspension and transmission built in Faenza.
This time, the integration between Red Bull and AlphaTauri is much closer. Both cars are using the same transmission and rear suspension layout, so there is huge technological transfer from Red Bull Technologies to AlphaTauri. This is perfectly legal within F1 rules.
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In terms of appearance, the sidepods are an evolution of those from last year, with a more rounded shape. They are moving towards the Red Bull concept, even if it is clear that the sidepods inlets are elongated and more closely resemble those of Ferrari.
This has not changed the AT04's main aerodynamic concept, which is to use this sculpted section underneath the sidepod in a manner similar to Red Bull.
At the front, a long, rounded nose tip can be seen. As this is just a rendering, it is difficult to know how closely this will resemble the real front wing.
The team appear to be seeking to maximise the wing's outwash capabilities, with the rearmost flap attached to the rear of the endplate.
They also look to be trying to increase the downforce generated by the front wing in its central section, where the width of the upper flap is wider, similar to what we have seen on the Alfa Romeo.
At present, the cooling on the car appears minimised, though some gills are likely to appear on top of the sidepods or the sides of the cockpit, or at the bottom of the engine bay, because so far the cooling looks really minimal.
It is also important to see that the T-shaped bodywork at the rear, which is a feature characteristic of Red Bull and AlphaTauri, blows the air towards the beam wing, which features a wider section of the flap in its centre part.
This is not only the proper way to use the beam wing, it's also essential to avoid hot air – which has a lower density than colder air – interfering with the diffuser.
If the hot air spills through underneath the diffuser, it would reduce the efficiency of the air extraction from underneath the car, because the speed of hot airflow is dramatically lower than that of colder airflow.
If hot air exits on top, the air needs to be energised again towards the exit of the diffuser, otherwise there is slower airflow and the diffuser doesn't work so efficiently.