McLaren have clearly used their time over the winter break to analyse the rules governing the new 2021 season very carefully. The new MCL35 appeared at Bahrain with an innovative rear diffuser that appears to have been designed to exploit the new regulations regarding the limit on vertical depth of the diffuser.
It does this by implementing a sloping underside that allows the diffusers bottom edge to be lower than any of the rival designs. This approach maximises the cars ability to leverage downforce at the rear of the car, creating a more stable back-end and potentially increasing speed through the corners.
It is in quite a stark contrast to solutions seen on the other cars where the strake depth is uniform across the diffuser.
The McLaren approach will almost certainly be evaluated by other teams to see if there is much of a performance gain there, however replicating it could be tricky as the design has been incorporated into the design of the gearbox housing, therefore requiring a ‘token’ spend to modify existing gearbox elements.
But with less than two weeks until the season opener, it is unlikely the other teams will be able to replicate this in time for the first, so they may just have to see how it works out for McLaren and then decide if the effort to replicate it is worth it.