Preview to the first part...
We have written previously about the length of the Formula 1 rulebook and how the 2022 version has grown, even when compared to an exponential rate of growth of the rulebook since the late-80s. In this article we aim to explain the rules, without simply quoting the regulation document verbatim. The full regulation document can be found on the FIA website for the intrepid few, or simply for the insomniacs who want some bedtime reading.
Before delving into the content of the rules, there is some technical jargon to learn as it is referenced in the regulations and will also be throughout this article. Firstly there are a number of reference planes in the Formula 1 regulations - 2-d slices which project through the cartesian aligned axes, x being the length axis, y the width, and z the height. These planes give the designers and the FIA common references for the design and scrutineering of the cars and include:
- → The longitudinal location of the front axle.
- → The longitudinal location of the rear axle, to is the wheelbase of the car which cannot be longer than 3.6m.
- → The longitudinal location of the front bulkhead, which cannot be more than 100mm ahead of .
- → The longitudinal location of the middle chassis bulkhead, this must be 875mm ahead of .
- → The longitudinal location of the rear of the cockpit entry template, which must be at least 1830mm behind .
- → The longitudinal location of the centre axis of the differential, must be within ±60mm of .
- → The car centre line and plane of symmetry for the car, the car must ostensibly be symmetrical except for some cooling variation and front wing flap adjustment.
- → The bottom of the car, also known as the reference plane.
Different parts of the car are defined relative to different planes, for example the front wing is defined by its position relative to the front axle (
), while the rear wing is given relative to its position from the rear axle (
), and the rear impact structure is a set distance behind
Another piece of nomenclature which will make this article easier to understand is the use of reference volumes (RV) and reference surfaces (RS). The volumes dictate the maximum dimension limits of bodywork, no bodywork can be visible outside the volumes, while the surfaces are used to dictate the minimum size of certain bodywork in specific projected views, i.e. from above, underneath, or from the side. The car is split into volumes for different groups of the car, front wing, rear wing, underbody, and front and rear bodywork.
Now that we’re all on the same page let’s take a look at the 2022 F1 regulations in detail.
Underbody and rear diffuser
The obvious place to start is with the biggest change in the 2022 rules, the return of underbody tunnels after 38 years of flat floors. This is not a return to ground effect as is often claimed; as ground effect is a physical phenomenon described as the increase in normal force (force acting into or out of the ground) resulting from smaller ground clearances. Any car with an undertray designed for producing downforce, as has been the case in F1 since the flat bottom rule came into effect, uses ground effect.
Like the whole car, the underbody group is split into multiple volumes, five in total with a further four surfaces, which are listed and described in the table below. The naming convention is pretty self explanatory, for example RV-FLOOR-BODY is the reference volume of the main body of the floor, and so forth.
Floor Body Reference Volume
Floor Fences Reference Volume
Floor Edge Wing Reference Volume
Bib Reference Volume
Bib Stay Reference Volume
Plank Reference Volume
Floor Body Planform Reference Surface
Floor Body Middle Reference Surface
Floor Body Rear Reference Surface
Floor Fences Reference Surface
The main geometry of the floor has to fit inside RV-FLOOR-BODY (light blue below). The definition of which sets the boundaries for the maximum and minimum height and width of the underbody tunnels. The diffuser exit is rather narrow, 750mm wide compared to 1050mm on the 2017-21 cars, and the shape of the floor volume will prevent teams from expanding their diffusers laterally, as they do now, which would subvert the aerodynamic concept for the 2022 cars, and allows only for expansion in the vertical direction, with the diffuser exit between 200mm and 310mm tall. The minimum height along the tunnels is 50mm, the same as the floor step which has been in place since 1995, and teams could choose to have a flat section in the middle of the tunnel to squeeze the tunnel as close to the ground as possible. There is a minimum permitted radius of curvature of 25mm, with the exception of the small region outside the tunnel and just ahead of the rear tyre. There will likely be some variation in tunnel shape between teams, but this will be largely hidden from public view - the underfloor is already an area teams are incredibly paranoid about showing to the competition. Anticipate some differences too between winter testing and round 1 (wherever that may be) as teams hide as much as they can until the last minute.
Along the outer edge of the floor is provision for a longitudinal wing (RV-FLOOR-EDGE, orange above). The edge wing will help provide some upwash and outwash around the outer edges of the floor to prevent air reentering the underbody tunnels ahead of the diffuser, often incorrectly called “sealing”, while this is a misnomer it can be said to have a pseudo-sealing effect. The edge wing has a number of rules pertaining to it’s geometry, with minimum cross sections and curvatures, and minimum and maximum offsets from the underlying underbody of 5mm to 20mm. The edge wing can be supported by up to six brackets, again with restrictions pertaining to their shape and outwash potential so that there is not a panoply of outwashing vanes littering the outer edge of the floor.
In order to be considered legal, the entire floor cannot be smaller than RS-FLOOR-PLAN (red below) in plan view. This surface shadows the shape of the floor reference volume with a 5mm inset around all the edges except the front corner, where there is a space for the front floor fences - more on those later.
In the middle of the tunnel is a boat section which splits the airflow around the driver's seat, as well as shrouding the engine and gearbox. The boat section has a maximum size from the RV-FLOOR-BODY, but also a minimum flat area enforced by RS-FLOOR-MID (teal below).
The bib (purple above) and bib stay (yellow above) volumes are relatively recent additions to the rulebook (so recent that the model FOM presented at Silverstone did not have a floor bib) and were added for safety and stiffness. The bib provides some frontal impact protection, while the stay prevents the front of the floor from bending upwards for aerodynamic advantage. The bib will create a sort of mini tea tray at the front of the floor's central boat shaped section, but is not really big enough to create a huge aerodynamic advantage, though there will be a vortex created around the junction between the bib and boat section. The bib must be at least 20mm thick with a radius of at least 5mm applied to edges facing the ground and 15mm on the other edges.
At the front of the floor is the floor fence region, RV-FLOOR-FENCE (grey below). In this region up to four (up from three in the original rule draft) large scale vortex generators (VGs) are permitted per side. These VGs perform a similar the function to the bargeboards, outwashing the front tyre wake, creating low static pressure (suction) at the front of the underbody, and producing vortices which help to increase suction along the length of the floor. The fences are defined in a similar way that the front wing endplates have been since the 2019 rule update, specifying a “virtual surface” from which bodywork can only be offset by up to ±4mm. The fences cannot be closer than 10mm to one another at any point, but could be used a bit like a multiple element wing, if flow separation is an issue, though that sacrifices one fence. The outwashing capability of the fences is curtailed by restricting the tangent angle at any point on the fence surface to 50° from the car centreline - by comparison current bargeboard designs create outwash at an angle almost perpendicular to the car centreline but are a key contributor to the wide wake which the FIA are trying to avoid with the 2022 regulations. Again the fences will probably be slightly different between teams, though largely hidden from view.
The final regulations for the underbody are that RS-FLOOR-REAR (green below) and RS-FLOOR-FENCE (blue below) must be obscured by the car from a side projection. The outermost of the four vortex generators under the floor must hide RS-FLOOR-FENCE, while the diffuser endfence must cover RS-FLOOR-REAR. The VG whose purpose it is to cover RS-FLOOR-FENCE cannot outwash the flow more than 40° from the car centreline, 10° less than the inner fences, to maintain the narrow width of the car wake.
Underneath the car the plank, which has been ubiquitous since the middle of 1994, is retained though it’s shape is slightly changed. The plank begins 430mm behind
and ends 600mm ahead of
, it is still 10mm thick and is the only bodywork permitted below
, but it is 50mm narrower than the existing plank. The shape is no longer rectilinear but narrows slightly towards the front edge because of the shape of the underbody’s boat section.