Did McLaren’s ‘mini-DRS’ rear wing trick help Piastri keep Leclerc at bay in Baku?

A new technical intrigue has arisen in the aftermath of the Azerbaijan Grand Prix, with McLaren’s rear wing under the spotlight.

Footage from the rear-facing onboard camera on Oscar Piastri’s MCL38 showed the upper flap distorting under load, with the most visible aspect of this being the outer leading edge of the upper flap which tilts upwards as speed builds.

This could potentially give rise to a further reduction in drag and boost its straightline speed and will once again bring the topic of flexi-wings to the fore.

So far the questions that have been raised this season have been in regard to the legality of some of the front-wing solutions on display. However, there’s clearly going to be a renewed interest in rear-wing deflection and flexible elements for the rest of this season.

The intrigue about the McLaren rear wing design comes after a race where Piastri was able to hold off Leclerc despite his rival having the DRS open advantage.

Flexi-wings have long been a source of irritation in Formula 1. After all, the teams are constantly seeking means to exploit aeroelasticity to improve the performance of their machines, whilst staying within the bounds of the static tests that the FIA employ to reduce their impact.

Of course, these components will always deform differently once load is applied on track, as it exceeds the values of the tests, which are more about establishing a baseline to prevent designs that could be considered unsafe.

However, this has led to the use of other tactics to help police matters, with the monitoring of onboard camera footage providing a means to establish how the deformation of components is occurring, which can, in turn, be used to alter the regulations and prevent matters further spiralling out of control.

This method was introduced in 2021, with the governing body requesting that all teams install 12 target dots in specific locations on the mainplane and upper flap.

This was in order that the dots could be used as a reference when the footage from the rear-facing camera is reviewed. These dots can be seen in the main image, six black dots on the upper flap and six white dots on the mainplane.

It’s understood that this had largely acted as a means to self-police the over-rotation of the rear wing assemblies and in the wake of accusations regarding flexible front wings this season a similar tactic has been employed during Friday’s practice sessions since the Belgian Grand Prix.

McLaren MCL38 rear wing detail

Photo by: Uncredited

Given that the FIA will have seen the upper flap’s leading edge rotating rearwards from the onboard footage (red arrow, inset), as it has been doing so for a number of races already this season, it would suggest the ruling body is happy that it’s within the constraints currently posed by the regulations.

In terms of the net effect of this flexion, it’s likely that the gap being between the upper flap and mainplane has a similar effect to DRS when it is deployed, albeit having nowhere near the same potency. But, given this occurs as load builds on the assembly it can be expected to offer a performance boost across the entirety of the lap.

For example, the flap flexion could also be witnessed in the middle sector in Azerbaijan, with the onboard footage showing the flap visibly lifting in the outer portion, as the upper flap pulled up clear of the tip section alongside, albeit not with the same force as it was on the main straight.

This ‘mini-DRS’, as it’s being dubbed, is another example of the ingenuity shown by Formula 1’s engineers, as they have found a way to interpret the regulations in a way that their rivals haven’t and gained an edge over them as a consequence.

The more interesting battle is yet to come though, as the rest of the teams will now undoubtedly look at how they can incorporate a similar design methodology, albeit it’s likely that McLaren has taken full advantage of it already this season, given we’ve already visited a large proportion of the hi-speed events on the calendar.