Regular wing or not?
The Baku race has reignited the discussion regarding the flexible wingsa theme that periodically recurs in Formula 1, but this time with a variation on the theme that is not secondary to the usual complaints seen several times over the years: in addition to the flexibility that more or less everyone on the grid exploits, we have seen an evident McLaren DRS flap movementwhich, as the images showed, had a tendency to open up slightly at high speeds, certainly helping Oscar Plates to repel Leclerc’s attacks at the end of the very long straight of the Azerbaijani track. This movement certainly represents a theme controversialand it is interesting to analyze in which particular conditions it occurs and why the rules do not expressly prohibit it.
How it works and why it only happens with the low-load wing
Let’s start from a point that is also relevant as to why this McLaren detail is only emerging now. The reason why the DRS flap lifts at high speeds it is not in fact due to the simple flexing of the rear wing, but to a concatenation of causes. The basic requirement why this happens is, in fact, that on the MCL38 the wing is mounted with the minimum aerodynamic load of those available to the Woking team. This is because what can be sensed to happen on the track is a real Flow reversal around the DRS flap. In practice, the unloaded rear wing already has a very low incidence, which translates into an almost horizontal orientation with respect to the track. At the moment in which the aerodynamic load at high speeds causes the rotation of the entire rear wing assembly of the single-seater (which happens more or less for everyone) the McLaren’s DRS flap, which already had a negligible angle of incidence, finds itself hit by a flow that is no longer aligned with the leading edge, but in fact hits the profile from below, thus making it rise. This therefore configures a unique and very particular case: first of all it happens only with the wing minimum loadand in fact it emerged after the races in Spa, Monza and now Baku. It also underlines how much therear wing of Norris and Piastri’s car and how much the single-seater expresses load from the bottom, allowing the incidence of the profiles to be lowered more than all the competition. With medium and high load rear wings this phenomenon cannot actually occur, since, even when the rear wing is flexed, the flow that hits the DRS flap is always deviated by the main wing profile of the wing, so never directly and therefore never from the bottom upwards. Indeed, in general, with medium and high load wings the DRS it tends to remain closed with the aerodynamic pressure on the wing, unless there are particular phenomena in which the flow hits the flap with a particular angle that generates a strong oscillation, as we have seen happen a few times on the Red Bull in recent seasons, but still never with a bottom-up flow.
The flexibility of profiles is accepted and regulated, this remains a borderline case not contemplated by the rules
The theme of the flexibility of the wings is a widely debated topic. Until a few years ago the regulation included the inapplicable rule which generically specified the stiffness requirements and of immobility of all components with an aerodynamic function. We define this rule as inapplicable because any element subjected to load undergoes a bending, even buildings exposed to the wind, so this phenomenon cannot be prevented upstream, but it is necessary to limit it numerically through rules. This was the path correctly undertaken by the Federation in this sense, in which instead of generic rules a series of tests (static) for each aerodynamic component, where you simply impose a certain load on the component, when stationary, and check that its deflection remains within the regulatory parameters. During this season, however, the continuous complaints submitted to the Federation by several teams regarding wings which, although passing the static tests, then show on the track a flexibility beyond a certain reasonablenesshave forced the Federation to consider at least one review of static test loads. For this reason, teams are now required to apply special pads on the wings markers which are used by FIA engineers to check the flexures at a dynamic level, but only for the purpose of investigative research, with the commitment made by the Federation itself not to modify any rule during the year. This last aspect is to be considered generally correct, since first of all the redesign and production of a wing requires at least 3 months, but above all any modifications required by changes in the rules during the year would have an impact on the budget cap of those who should intervene while respecting the parameters imposed by the regulation since the beginning of the year. For this reason, the approach adopted in this sense appears reasonable. As regards the “mini DRS” (as it was baptized by the internet) of the McLarenhowever, we find ourselves in unexplored territory and above all completely unregulatedThe flexibility of the individual profiles is regulated precisely, and it cannot be argued that the rear wing of the MCL38 bends beyond what is due as it is subject to regular checks, which are always promptly passed. On the other hand, it is quite evident that the DRS semi-opening go against the regulatory spirit (which, as mentioned, initially even claimed to prohibit any type of flexibility) but, from our in-depth reading of the technical regulation, there is no rule that contemplates an explicit prohibition, in fact a regulation hole. Some refer to the norm 3.10.10.gwhich requires that any alteration of the flap incidence of the DRS can only be controlled by an input from the pilot and controlled via dedicated electronic controls. In reality, this rule, although it is a matter for lawyers rather than engineers in this case, imposes a limit on the control system of the mobile wing and not on a possible passive movement of it, being in fact introduced only to prevent the existence of automatic systems that open the mobile wing when passing over the relative line without the intervention of the pilot. Rather, the previous point appears more delicate, the 3.10.10.fwhich requires that the system of DRS have a designed so that, in the event of a failure, the wing remains closedThis rule was introduced for obvious reasons of safety and it is plausible to think that, on the straights of Baku, the MCL38 was very much on the edge in this regard, as a break would probably have opened the mobile wing completely. This, however, remains a point clearly very difficult to prove, probably the reason why no one has appealed to it to date.
A hole in the rules that needs to be closed, but which we will probably only see again in Las Vegas
In conclusion, therefore, this system used in the tracks at low load from the McLaren exploit what is currently a regulatory vacuumand on which the Federation will necessarily have to intervene for the next season together with the revision of the static tests. That said, the only track still to be tackled where the low-load wings will be used is that of Las Vegasat the third to last appointment of the season, and it will be interesting to observe if the men of Andrea Star they will have tried to eliminate the effect “mini DRS”, or if we will see him at work again.
#McLaren #Flexible #Wing #MiniDRS #Work #Legal
