How the bodywork rules shape Formula 1 cars (long read)

The bodywork and aerodynamic rules of F1 cars are described in Article 3 of the FIA Formula 1 regulations (there are a total of 22 articles in the current regulation, describing engines, wheels, crash tests... etc). Article 3 is used to describe where bodywork is permitted, and more recently, is used to define what sort of bodywork is permitted or outright required in certain places. As time has gone on, when teams have circumvented and subverted the intent of the regulations, or just to reduce speeds to improve the safety of the cars, the length of Article 3 has risen at a near exponential rate from 514 words in 1988, to over 10,000 words in 2021 (see below). It has been said that the 2022 regs will be the most prescriptive ever, and the Article 3 word count would seem to support that, rising to nearly 16,000 words with the next generation rules - that’s the sum of the 2011 and 2020 rules.

Article 3 typically describes a 3-dimensional shape in which the bodywork must be placed, in this piece we take a look at what the Article 3 volume looks like, and how it has changed with the ever more restrictive wording over the past 30 odd years.

1988

Between 1983 and 1992 the rule box created by the regulations was fairly consistent and relatively simple by modern standards. The maximum permitted width of the cars was 2150mm, with bodywork ahead of the front axle line 1500mm wide, between the axles 1400mm wide, and behind the rear axle 1000mm wide. The maximum overhangs (i.e. the distance ahead of the front axle and behind the rear axle) were 1200mm at the front and 600mm at the rear, while bodywork could be up to 1000mm from the ground. Bodywork wider than 1000mm could not be taller than the height of the rear tyre, while bodywork wider than 1100mm and ahead of the front wheels could only extend to the height of the front wheel rim. With the flat bottom rule, bodywork facing the ground had to be flat between the rear face of the front tyres, to the front face of the rear tyres.

Cars created in this period were incredibly diverse, mainly owing to different requirements between naturally aspirated and turbo powered cars. There was a greater spirit of experimentation and innovation, as many of the aerodynamic solutions were novel at the time. The design process was also primarily led by “designers” rather than by pure aerodynamic optimization methods.

1994

For 1994 the absolute width of the cars was reduced from 2150mm to 2000mm, with a reduction of the rear tyre width from 406mm (16”) to 356mm (14”) to reduce absolute grip. The FIA also decided to enforce Article 3.7 more stringently - prohibiting the use of active suspension systems to control ride height by defining it as a moveable aerodynamic device. Bodywork ahead of the front wheels was also reduced in width from 1500mm to 1400mm to match the width of the body between the wheels.

Bodywork behind the rear axle line was reduced in height in 1993 from 1000mm above the ground to 950mm, while the length of the rear overhang also reduced from 600mm to 500mm. This produced some rather awkward solutions in 1993 as teams tried to claw back some rear downforce - with the “step” of the regulation volume clear to see on the mid-wings (see the distinct endplate step down in the image below) that some teams used at higher downforce circuits. For 1994, the front overhang was reduced to 900mm for bodywork further than 200mm from the car centreline, moving the leading edge of the front wing rearwards. The lower bodywork more than 250mm from the car centreline, and ahead of the front tyre, was also moved up and away from the ground by 40mm, reducing the ground effect of the front wing and therefore, reducing overall front wing downforce. The rearward and upward translation of the front wing reduced the moment arm from the wing and moved the aerodynamic centre rearwards (the balance point of the aerodynamic downforce acting around the car). This had the effect of making the mid-wings (shown below) unnecessary as they would move the aerodynamic centre too far rearward of the aerodynamic sweet-spot and they fell out of vogue.

1994 - post Imola

In reaction to the tragic events of the Imola race weekend in 1994, and further heavy crashes in the practice sessions for the Monaco Grand Prix two weeks later, the FIA made a number of hurried, but ultimately necessary, changes to the regulation box in an effort to slow the cars down. These included the addition of the now ubiquitous underbody plank, which is a 10mm thick block of wood (modern planks are made of a composite material called Jabroc which is more consistent in wear and weight distribution than natural wood) to enforce a minimum ground clearance and prevent the underbodies from stalling - which causes a dramatic drop in downforce. The planks have a number of holes in the surface at which the thickness is measured to ensure teams are not running their cars too low. Michael Schumacher was disqualified from Spa 1994 when his Benetton’s plank was found to have worn by more than the 1mm allowed. The plank was 300mm wide and spanned the length of the mandated flat section of floor as described in the 1988 section.

To reduce downforce even further, the diffuser also had a large chunk cut away, removing any bodywork behind the rear axle line and below a height of 300mm. There was also a change to prevent front wing endplates extending beyond the front wheel, effectively stopping the long tunnels used behind the front wing to control the wakes of the front wing and wheels. In the two weeks between the Monaco and Spanish Grands Prix, teams were literally taking hacksaws to their wind tunnel models and cars to test the effect of these rather crude changes.

1997

Following on from the rushed changes made mid-season in 1994, a number of more considered changes were made in 1995 to further reduce the downforce of the cars, and the regulation volume began to take a form more familiar to today's aerodynamicists; almost resembling a very simple Lego model of an F1 car.

The height of the cars was no longer measured relative to the ground, but to the bottom of the car, otherwise known as “the reference plane”. A 50mm tall, 500mm wide step was added under the floor on top of the 10mm thick plank. The plank was also lengthened so that it would terminate at the rear axle line, all in the hopes of minimizing the ground effect downforce. The bottom of the front wing was also moved from 40mm to 50mm above the ground, and the front wing maximum height was reduced from the top of the wheel rim to 200mm above the reference plane. Finally, a large exclusion zone was added around the front wheels, preventing any bodywork from being situated there - with the exception of suspension arms and brake ducts.

Around the back end of the car, a series of exclusion zones were added to limit the height of the sidepods, the length of the engine cover, and to make the rear wing smaller. As is typical for the FIA, some loopholes remained; for example, the exclusion zone for the tops of the sidepods only started at the longitudinal position of the rear roll hoop. This left some space for bodywork around the centre of the car that was allowed to extend up to the maximum height, a loophole that Tyrrell exploited in 1997 with their infamous “X-wings” (the small red wings shown below).

1998

Despite a move from 2000mm wide cars to the much maligned 1800mm narrow track cars, the actual specification of the bodywork volume did not change for 1998. The X-wing loophole remained and was exploited by most teams, including Ferrari, until the FIA declared the wings unsafe; using article 2.3 which states, “The stewards of the meeting may exclude a vehicle whose construction is deemed to be dangerous”, and ultimately banned them. For 1999, the sidepod height limit was extended forwards to prevent any future protuberances sprouting.

2001

Going through the 2000s, only a series of aesthetically minor changes were made to the shape of the volume of the regulation box. In 2001, the front wing region was moved upwards by 50mm to a minimum height of 100mm, and the rear wing region was limited once again to reduce placement of bodywork outside of a specified volume. But the word count continued to grow following the near exponential trend, indicating the ever increasing detail required to describe the bodywork permitted within the rule volume. For example, the upper rear wing was restricted to only 3-elements and a section for bodywork flexibility tests were added to the rule book in 2003 to counter the trend of flexing wings, which had resulted in some high speed accidents when wing mounts had broken under load. These have become more and more comprehensive and stringent to this day because teams have continued to push the boundaries of rules, and are a significant reason as to why Article 3 continues to increase in length.

As the bodywork above the monocoque and nose could be 500mm wide up to the maximum car height of 950mm, Arrows and Jordan both trialled narrow (500mm span) wings mounted up high but ahead of the driver. The Arrows solution mounted a wing from the nose (see below), whilst the Jordan solution was to mount a wing from a single post ahead of the driver, not too dissimilar to the position of the halo-front-strut today. Both were banned, though not by changing the Article 3 volume; but rather using article 2.3 (quoted above) where the FIA stewards deemed these features to be unsafe. The same rule was again used to prohibit the tower winglets which appeared on the BMW Saubers in practice for Magny Cours in 2006.

2004

The increasing verbosity continued through to 2004 with the addition of minimum projected areas, in side-view, for the engine cover and rear wing endplates. The new definition of the engine cover opened a loophole which would later be exploited to produce the divisive shark-fins - which help to improve lateral stability when cornering. The cross section of the rear wing elements also became limited by area, and so while the aesthetics of the cars remained fairly stable, the freedoms in design continued to be gradually eroded.

It was during this period when it began to be said that if all cars were painted black even the team bosses would struggle to identify their own car, a complaint which persists to this day - and likely won’t change for 2022, but more on that later!

2005

2004 saw some of the fastest laps ever in Formula 1 - the records from which remained up until the 2019 and 2020 seasons where many were finally beaten. As a result of this, in 2005 the FIA decided to cut downforce once again. This was achieved by further raising the front wing tips, to a minimum of 150mm, and a raising of the central section under the front wing by 50mm - “spoon” shaped wings became the norm as teams reduced the wings height as much they could near the centre-span to maximise downforce. The upper rear wing box was moved 150mm forward and the number of elements were reduced from three to two, with the lower beam wing restricted to just a single element. The rear wing endplates were made even larger to increase sponsor visibility. A further exclusion zone was added ahead of the rear wheels to further limit the underbody, and the fences within the diffuser were required to be straight though their vertical axis - where previously, teams used quite complex 3-d shapes. Again, nothing major was changed in the aesthetics of the regulation box, but another 500 words of restrictions, addenda, and clarifications had been added to the Article 3 rules.

2009

2009 marked the start of a major rule change to try and help cars follow one another. In fact, this precept remained in the rules between 2009 and 2016: “one of the purposes of the regulations under Article 3 below is to minimize the detrimental effect that the wake of a car may have on a following car.”

The volume produced was fairly similar in execution to the preceding rules, defining a cuboid and then removing regions, albeit with obviously bigger exclusion zones around the front wheels (shown below) and under the monocoque and nose - where only the FIA mandated “neutral” wing section and a pair of mounting pylons could sit. The length of Article 3 jumped above the rate of growth seen through the 2000s, with a lot of the added complexity pertaining to the front wing. Further regions were defined in which the front wing cross sectional area was limited, as well as minimum projected areas for the endplate and footplate.

Another addition to Article 3 was the 75mm radius or “R75 Volume” (orange below), which was a secondary volume within which bodywork must be thick enough to have a 75mm radius applied to it’s edge. This effectively prohibited the cooling chimneys, cooling louvers, winglets and dive planes which had cluttered the back end of cars by the end of 2008. The result was a much “cleaner” looking car, but once again, the increasing constraints from the regulations saw Article 3 double in total length again within just 5 years.

For the first time in 2009, the FIA trialled moveable aerodynamic devices with the front wing flap being adjustable by ±3° from its set position. The front wing flap adjuster had little impact on wheel-to-wheel action and so was replaced in 2011 by the universally disliked rear wing drag reduction system (DRS).

2012

Between 2009 and 2011 teams determined that the optimal solution at the front of the car was to raise the nose tip as high as possible to maximise airflow to the keel (the vertical splitter under the monocoque ahead of the driver’s backside) and sidepod undercuts. This produced some dangerous moments such as Webber’s airborne crash in Valencia, and Liuzzi riding up over the top lip of Schumacher’s cockpit in Abu Dhabi. The solution for 2012 was to cut out a region from the rule volume to lower the nose tip to a maximum height of 550mm.

The result was some awkward stepped transitions from the monocoque to the front impact structure as teams retained the high monocoque to keep the aerodynamic gains found in the previous years. In 2013 a “vanity panel” was allowed in the exclusion zone to smooth the step, provided it was a non-structural part.

Other changes included the addition of a cutout ahead of the rear wing in 2011 to prevent shark fins from joining the rear wing - preventing the very well known “f-duct” rear wing stalling trick which McLaren had introduced in 2010. During this period, Red Bull had also introduced the concept of off-throttle exhaust-blown aerodynamics, which the FIA gradually prohibited, though in this case using Article 5 - the engine section of the rulebook - to move the exhaust location.

For 2011 the FIA added a section to the rules which closed the loophole that had allowed double diffusers that Brawn, Toyota, and Williams introduced, in 2009 before being copied by everyone else in 2010. Though some still maintain that such a loophole never existed and double diffusers were always illegal.

2014

2014 marked the transition from naturally aspirated V8s to the current turbo-hybrid engine formula. 2014 stands out among other seasons in that the total word count of Article 3 actually reduced from 2013 (see graph). Further to the nose change made in 2012 the front impact structure was lowered under the axle height, to 230mm, with an angled exclusion zone dependent on the length of the frontal impact structure - Mercedes opted for a short nose with a steep transition while most other teams chose a longer nose with a shallower angle.

The wording defining the front impact absorbing structure (15.4.3) produced one of the ugliest grids in F1 history (Caterham CT05 below) as teams tried to minimize the cross section of the nose to minimize the disruption of airflow to the keel - the same reason for the high noses in 2011. Subsequently this rule was tweaked to try and prevent these solutions, but the “thumb” type nose cone has persisted.

2017

For 2017, and on the back of complaints from drivers, fans, and pundits, F1 decided to try and make the cars faster and more aggressive looking. This included adding a sweep angle to the front wing, slanting the rear wing endplates backwards, and adding large angled regions for bargeboards.

The FIA cut a section out of the engine cover in 2011 to prevent shark-fins, and yet despite this fact as well as knowing that teams will always exploit any loophole they can find, shark-fins returned in 2017. However, this time, they also left an additional loophole which created the aesthetic blight known as the coathanger or T-wing, by leaving a 500mm wide, 50mm long block situated just behind the R75 volume. In response to this, the FIA would eventually cut a triangle out of the engine cover volume for 2018, but even so, the space remains for lower mounted T-wings.

2019

When the 2017 rule change had the predictable impact of making wheel-to-wheel action even harder than before, the FIA had to quickly try and reduce the negative effect of “dirty air”. They aspired to this by massively simplifying the front wing, ironically by massively complicating the rules defining the wing. Changes included limiting the wing to 5-elements, and definition changes to the endplate and the out-wash potential of the wing.

2021

The intent of the 2021 rules was to retain as much of the 2020 cars as was possible to save costs in the midst of a global health pandemic. The FIA implemented changes to the outer edge of the floors by cutting a triangle of floor away between the rear face of the cockpit entry template and the rear axle line (shown below compared to the 2020 rules), and then additionally prohibiting the slots which had grown in number and complexity through the 2010s. As a result of these changes teams have had to spend a significant amount of money to design and optimize new floors, costing not only the value of the carbon parts but also the accumulated weeks spent in the wind tunnel and CFD - rather defeating the purpose of cost cutting during a global pandemic. However, these changes were made under the new financial restrictions, originally planned to arrive with the new regulations, somewhat levelling the playing field.

There were other aerodynamic changes to the rear brake ducts, which according to the findings of the FIA in the Racing Point “copying” ruling cost at least $400,000, but these are defined in Article 11.

2022

For 2022 F1 is returning to an ethos of producing cars that can race with and overtake one another more easily.
Article 3 will no longer describe the dimensions of the regulation volumes, instead teams will input their wheelbase, front bulkhead and differential locations into the FIA CAD portal, with the volumes autogenerating for download. Also, instead of a single volume for the bodywork, the 2022 regulations are split into a number of smaller volumes, each of which has a long list of rules pertaining to what can be contained within them. There are individual volumes for the front and rear wings (even splitting profiles from endplates), nose, front and rear monocoque, engine cover, separate volumes for the sidepod inlet and coke bottle sections, wing mirrors, underbody, underbody vanes, even the exhaust tail pipe gets its own volume! Despite Article 3 solely describing what is permitted within each of these 26 separate volumes, the word count has increased significantly more than the exponential rate to nearly 16,000 words.

However, the details of how to produce the bodywork volumes are included in the appendix to the regulations - adding this to the word count for Article 3, to directly compare to previous years, increases the length of the bodywork rules to a mind boggling 23,089 words!

This piece has only focused on summarizing the aerodynamic regulation boxes described in Article 3. The length of the complete regulation document has increased from 11 pages covering 16 articles in 1988, to 169 pages covering 18 articles at well over 75,000 words for 2022; longer than many novels! It is clear that for 2022 the FIA and FOM have a picture in mind for how a Formula 1 car should look, and have tried to come up with a regulation set which forces teams into that aesthetic. There should be a benefit by reducing the negative effect of a leading car’s wake, but the cost is that areas of creative freedom are being forced into ever smaller regions of the car.

There are a myriad of other reasons why regulation is important - not least for ensuring the grid remains competitive with one other - but creativity and the magic that comes with it, is clearly being lost as a result of the clamping down hard on teams to fulfil this “vision” that the FIA and FOM have for Formula 1. It’s easy to see why Adrian Newey, among others, are so unimpressed by this regulation and see it as anathema to the spirit of innovation and experimentation associated with Formula 1, even going as far as to suggest it is a GP1 formula. It is yet to be seen how different the cars will actually appear when they hit the track in 2022, but don’t hold much hope for there being many visual differences between concepts from the most prescriptive and monolithic regulation ever conceived.