Sala Stampa F1

The Mercedes “Secret”: “Air-Duct” at the rear, to improve the Performance.

The tests just concluded in Bahrain have left us a series of questions in relation to the leitmotiv of recent years, or rather the overwhelming Mercedes that we have come to know since Day 1 of the pre-season tests.

There are many hypotheses on these three days in which we worked as always at 360 ° on the areas of the cars that roughly retrace those of 2020 for setup and aerodynamic configuration. The modification to the flat bottom that created a loss of load of about 10% (partially or completely recovered according to the technicians), is a modification that is not very invasive to the point of not upsetting the general performance of the cars.

For example, it is difficult to think of a Mercedes with such an “aggressive” behavior after having seen a 2020 season with a car literally on the rails rather, it is plausible that the teams and therefore also the reigning World Champions have tried various solutions of different kind, which for obvious reasons have the experimental result sought in the function of the test. Staying in the home of the much talked about world champions. The attentive eyes of SalaStampaF1 have noticed a detail on the Silver Arrows that can be traced back to the concept of “Air-Duct”. Let’s try to give some ideas while remaining in the context of the hypotheses, it being understood that an element such as “air duct” could have various purposes of use. In a racing engine, adequate cooling is required to allow efficient delivery of power to every need, which in turn requires sufficient air flow. The cooling system is usually governed by the so-called “Ram-Driven” (especially provided air intakes) and by integrated flow cooling systems as directed ducts.

Mercedes W12. Possible duct inside the bellies to dispose of the hot air generated by the PU, a duct useful not only for this purpose, but also to refine and clean the flows coming from the front. In the image at the top left, you can see the vent point of the duct, a sort of “gill”.

One of the hypotheses that we can analyze for the presumed presence of an Air Duct (specifically the one glimpsed by SalaStampaF1), is in fact that of an added “cooling” system that can bring benefits to the handling of the car; in fact, we must not think of the aerodynamic “suit” sewn on the various cars, as an entity independent from the other vehicle systems but, on the contrary, the interaction of the aerodynamic setup with everything concerning the energy exchangers in the form of heat, is essential for optimal balance. The heat exchangers (radiators) and therefore any associated cooling ducts can be sized precisely according to this objective. The optimization of the surfaces both from the point of view of position and design can certainly lead to a decrease in the maximum weight of the complex cooling system and therefore consequently an aerodynamic benefit which is evident in the performance.

Mercedes Front Brake Duct

The front Brake Duct seen in the tests on the W12, has a more generous architecture, allowing wider inlet ducts. The highlighted internal ducts (points 3 – 4 – 5 in the picture above) have the same shape as on the 2020 version, a sign that the internal ducting has not undergone particular changes.

About the Steering Rod, in the W11 the arm crosses the air intake dividing the upper and lower ducts in two. In the 2021 version, the solution is maintained, but the fairing is totally different: if before this was clearly visible, it is now well integrated into the architecture of the air intake.

In the 2021 version, the area in the red circle (point 1) is covered by the same structure as the air intake, it is likely that the air flow at that point could have generate turbulence, and with this new specification a critical point has been resolved of the previous version.

The same shape of the new Brake Duct seems in fact designed to not only better direct the flows for the internal ducts, but also to convey them under the arms of the front suspension, thus maximizing stability and avoiding turbulent flows, addressed to Bargeboards.

The Hub Clamp Flange (point 6) in the W11 version had a series of holes, a solution adopted throughout the season. In this W12 test-version, this solution is no longer present, it is likely that there is no longer the need to dispose of heat with this system, given the new shape of the Brake Duct.

Furthermore, the Pivot (point 2) above the brake basket does not appear to have undergone any changes. One of the points where Mercedes was studying in 2020, was to verify whether the introduction of the new shoulder of the Pirelli PZero involved changes necessary for this purpose.

Floor W12

Mercedes presented a wavy-shaped floor, arousing a lot of attention, a solution also adopted by AstonMartin, but the most interesting point of the 2021 solution is the purple zone (point 1). Mercedes has created a sort of “hollow” in that area to maximize the load. Point of further attention are the small flow deviators placed in the terminal part of the floor, (point 2), generating and stabilizing the vortices before impacting the rear tires.

It is interesting to note, the modification of the fairing of the lower arm of the suspension, on the W11 it had a curvilinear trend, on the W12 there is a very linear trend, almost forming a wing plane.

Rear and Diffuser

Although the W12 did not stand out in the tests, for visibly extreme solutions, at the rear there are some tricks made by the Brackley team to refine the W12.

We find a section of the heat vents of the bonnet, very tapered, a concept not new to Mercedes, but on the new single-seater, it is exasperated leading to very small sections, (yellow arrows).

Small changes also to the outer edge of the diffuser, in the image above you can see how the small element that joined the ends, in the new solution is broken with a precise trend. In addition, the same lower edge has a more twisted shape to improve the extraction of the flows below the diffuser.

To conclude some considerations on the W12 seen in Bahrain last week. We do not expect a Mercedes with the difficulties shown in the tests, the car was a real laboratory, the program as anticipated, modified from the first day due to gearbox issue, led the team to run and maintain a tighter pace and short runs, with high fuel load and very low engine mapping. The instability at the rear leads us to assume a targeted work of researching a very specific mechanical setup for the new aerodynamic load configuration, imposed by new regulation.

Davide Cacciotto

Fulvio Vigilante

Ing. Daniele Musco