Aston Martin launched the first Formula One car of its new era on Wednesday, before conducting a shakedown at Silverstone the following day. While it would be an over-statement to suggest that the AMR21 is a clean break from the past in the same way as the team’s image is, there are a number of key differences to the Racing Point RP20. Starting at the front of the car, a new front wing has been introduced, which takes inspiration from the two designs that the team alternated between during the 2020 season.
In 2020, the second option featured a redistribution of load inboard at the expense of the mid-span, achieved with flap re-profiling. For this year, the mid-span of the wing resembles this version, but the inboard is as the first option from 2020, while outboard, the flap is more aggressive than either. It is possible that the team is trying to reduce the load of the wing in front of the brake ducts, thereby reducing the losses entering them. This would improve both cooling of the brakes, and the mass flow through the wheel, which is used to push the front wheel wake outboard. Decreasing the upwash here may also improve the tyre squirt losses generated at the contact patch, although the varying position of the tyre with steering lock suggests this change would perhaps be too local if that were the intention. Regardless, by offloading the wing in one region, it is necessary to load it up elsewhere to retain a balance range that covers all circuits on the calendar. Perhaps the team has found a better compromise by doing this outboard for 2021 compared to further inboard last year. Finally, an additional slot gap separator has been added between the upper two elements.
Above the bargeboards, the lifting section at the top of the chassis on the RP20 has been removed. This would have produced some downwash to load the forward floor, and possibly also deliver high energy flow to the sidepod inlet. Given this inlet is now much higher, the benefits of this device may have been reduced.
A significant amount of detailed work has gone on around the mid part of the AMR21. The bargeboard concept has been carried over, but an additional slot has been added to the top of the bargeboard. This will offload the upper bargeboard vortex system, but also reduce the losses from the vortices shed here, which improves performance under the leading edge of the floor. Meanwhile, two new lower bargeboard elements have been introduced, similarly to last year’s Mercedes, though it must be said this has also been a grid trend. This should help relieve any airflow separation issues when these elements are most loaded.
The element connecting the front of the horizontal sidepod vanes has been split into two discrete parts on the new car. This part is useful for two reasons – firstly, it pressurises the region inboard, reducing the ingress of the lower wheel wake, but secondly, it can also produce some thrust, thanks to the suction on its forward/outward facing surface. Getting these elements fully vertical by splitting them off will maximise the latter effect as the pressure force acts fully in the longitudinal direction. Beneath the ‘JCB’ logo, on the rearward vertical element of the sidepod vanes, the attachment of the two horizontal elements has been altered, and the team looks to be trying to produce a little extra local load here with some upwashing sections.
Looking at the sidepods, their shape has changed significantly, with the big downwash slope introduced mid-season in 2020 no longer employed to the same extent, a more conventional coke-bottle shape where the bodywork intersects the floor taking its place. There are two ways to feed high energy flow into the gap between the rear tyre and the edge of the diffuser, which is a vital flow feature on the current generation of F1 cars, as this good quality flow reduces the ingress of the rear tyre squirt into the diffuser. The first is to feed flow over the top of the sidepod, which was clearly the direction pursued last year. The other option is to feed flow beneath the sidepod inlet and round the coke-bottle, in the ‘undercut’ region. With a raised sidepod inlet (see image below), there is much more scope for this second option to be employed.
Taking a closer look at the sidepod inlet, the upper side impact structure tube has been lowered, which was something the team already had in 2019. However, given last year’s car aimed to replicate the concept of the 2019 Mercedes, the team reverted on this for 2020. Moving the tube low down is advantageous because it gives much more freedom in the design of the vanes above and to the side of the inlet. The inlet is now significantly higher, helping feed the sidepod undercut as mentioned above. A new down washing vane has been added to the side of the inlet, which will produce lift in its own right, but help with the process of pulling high energy flow down and inboard of the rear tyre, benefitting rear downforce. The mirror stay has been extended down, perhaps for structural reasons to minimise the deflection of the horizontal sidepod vane. Finally in this area, the outboard vertical element has been dropped and the horizontal element extended outboard. This may be to allow two counter-rotating vortices from these two element to create an out washing jet into the wheel wake.
Moving further rearward, a blister is now apparent on the engine cover, also seen on the Mercedes, albeit to a lesser extent. It is likely this is due to revised power unit architecture, and clearly the trade-off favours the PU over the small aerodynamic losses. The upwashing part of the floor has been extended rearward, more similar to the position in which the RP20 started last season, while the three outwashing fins have been moved further forward. These fins will help to produce a little outwash, keeping the low wheel wake at bay. Right at the back of the floor, there is a multi-element device that will look to shed a vortex that interacts with the main floor edge vortex, which is much less clean than in previous years owing to the removal in floor edge slots for 2021. We have seen a similar device on the Red Bull, but that was only a single element – more elements will help maintain flow health over the range of conditions the car sees, both locally on the elements, and in terms of the vortex that is shed.
Looking at a more front-on view of the floor edge, a discontinuity is apparent just after the upwashing curl ends. The dashed red line shows the permitted floor area by regulation, and in not using this fully, some downforce will be lost across the floor, particularly locally. However, this will be overcome by better control of the vortex shed off this part of the floor, improving diffuser performance.
The rear wing used for the shakedown was the same as one of the options available last season, but the gearbox wing (also known as the T-wing) has been modified subtly. Inboard, the junction between the lower element and the vertical stay has been re-profiled, probably looking at cleaning up losses. At the tip, a long endplate was already in use last year to lower the vortex shed and reduce the negative impact it has on the stability of the rear wing outboard . For 2021, this tip has been kinked inboard low down, which might nudge the vortex a little inboard, and could also offload it by locally reducing the pressure difference.
Of all the cars launched so far, the AMR21 is one of the most changed from its predecessor, particularly around the forward sidepod region. The only downside to this tighter packaging could be some cooling issues, however it should be noted that last year the team ran the same engine cover exit for the entire season, so it is possible they were giving away some performance at the less demanding circuits for cooling, which they have addressed for this season.
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