We have had a great response to the launch of this seasonal special series on tech talking points from 2017, so here is the second of the five topics.
We’re going to get close to the ground to inspect the growing influence of floor slots.
In previous iterations of F1 floor designs, a small number of slots had been used to reduce the effect of “tyre squirt” at the rear of the car but, thanks to a loophole in the 2017 regulations, teams have been able to trial more outlandish solutions.
When the FIA widened the maximum allowable bounding box for bodywork by 200mm, the regulation for “continuous” bodywork on the car’s floor remained the same as the previous season.
This gave teams the chance to exploit a 100mm area on the outboard edge of the floor to experiment with slots and cuts parallel to the sidepod geometry.
Two key variations in the early season existed: McLaren (above), Haas and Toro Rosso trialled a slot with a raised trailing edge, shaped to carry further vortices outboard, as indicated with the yellow arrow.
This is to reduce interface with the rear wheel, minimising the effect of the vortical wake produced by the rotation of the wheel creating a range of unpredictable flow patterns.
Meanwhile, Mercedes and Ferrari had both considered different solutions to the floor slots, and both trialled their initial solutions with a trailing edge cut away from the floor.
Below is the Ferrari solution, which is provided with some concave curvature in order to manage the flow emanating from the bargeboard region, using the slot to bleed off low-pressure airflow and working it with the curved lip to help seal the floor in the diffuser area.
Ferrari soon had to bolster the cutaway section with a small metal insert, having experienced some dramatic fluttering at high speed which will have disturbed the predicted airflow patterns.
The ultimate principle behind each floor slot design is the same. Teams have identified the need to introduce a vortex along the floor’s edge to help seal the diffuser, which reduces the chance of turbulent flow bleeding into it.
With a more consistent flow pattern in the working part of the floor, the overall pressure distribution of the diffuser itself is more even, providing a more consistent downforce output. Combined with the existing bargeboard pieces, the airflow can be directed through these slots with minimal additions to the current aerodynamic packages.
At this sharp trailing edge, the teams are able to create a small vortex to carry along the edge of the floor and stop “dirty” air from drifting underneath the floor.
Teams soon began to work with this area further, and appeared to find greater gains through augmenting the scalloped section of the floor with an extra vortex generator to carry the circulating airflow along the edge of the floor.
Designs varied in their extremities, McLaren electing to stick with the slot alone while the likes of Renault, Red Bull and Force India eschewed the slot’s inclusion and incorporated just the vortex generators (red arrow) to work airflow aft of the bargeboard geometry.
Whether teams will choose to pursue further gains in this area remains to be seen, as the teams appear to have not reached a consensus over their usefulness.
Ultimately, incorporating any new design idea into a car must work in tandem with the existing package, and so perhaps teams will have been able to consider the slots at an earlier stage in their car’s development.
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