Motorsport.com looks back at how changes to the Formula 1 regulations affected the landscape of the sport in the past. Part 1: the 1970 and 1980s.
Formula 1's relationship with aerodynamics can be traced back to the first cars, even if they were more about streamlining rather than creating downforce.
Early misguided attempts at using large airfoils were curtailed before the 70s got underway but it's the ground effect era that many hold as the true emergence of a sport guided both by driver skill and technical innovation.
Ground Effect era
The late 70s and early 80s were dominated by ground effect cars as Colin Chapman's Team Lotus in particular led the way.
The Lotus 78 used inverted wing shapes placed within the sidepods, creating two large venturi tunnels, but it was its use of sliding skirts that was the real coup and radically increased downforce.
The skirts bridged the gap between the track surface and the side of the car, closing off the venturi tunnels and significantly increasing downforce for a disproportional amount of drag.
The first of its generation, the 78 finally gave way to the 79, which placed even more focus on extracting downforce from ground effect, with longer venturi tunnels and diffuser deployed.
Poor brakes and torsional stiffness made the Lotus difficult to drive, which, especially given the increase in cornering speeds that could be achieved, negated the downforce that could be generated.
Set-up of these early ground effect cars was also difficult, with ever stiffer suspension needed to counteract the downforce, making the ride both unbearable for the driver and sometimes inconsistent in its delivery of downforce as it acted in opposition to the skirts due to changes in ride height from undulations in the track surface.
However, such was their early dominance that the other teams could ill afford not develop their own version - but as they did, it became increasingly obvious that they'd supersede the Lotus version, not because their grasp of ground effect was better but because of the overall package, as the '79' was less well equipped elsewhere than its competitors.
The Brabham BT46B or as most know it, 'the fan car', was one such example of a desire to improve on what Lotus had already been doing.
The other teams protested its design on first sight but the sport's regulators upheld Brabham's claims that the primary function of the fan was to cool the car and any other side effects were simply a fringe benefit of the fan.
Of course, nothing could be further from the truth. The fan was a crucial element of making the BT46B a step beyond anything else on the grid and took cues from the Chaparral 2J as it too used both skirts and fans to increase downforce.
It was therefore a clever exploitation of the regulations, but even the team knew that the car wasn't strictly legal and withdrew it from competition after just one race, as Niki Lauda cruised to victory by over 30 seconds.
As the 70s gave way to the 80s, it became apparent that teams were pushing the boundaries and spurning wings for even more aggressive ground effect solutions, not always for the betterment of performance.
As cornering speeds and g-forces ramped up, the FIA stepped in, banning side skirts in 1981 and mandating a 6cm ground clearance.
But the teams weren't willing to give up the performance advantage that ground effect had afforded - and several new solutions arose.
The Lotus 88's 'twin-chassis' was an innovative way of getting around the ground clearance problem but never actually raced, much to the relief of their drivers, who claimed that the car was very unpredictable when they tested it.
Brabham resolved the problem utilising hydropneumatic suspension, which allowed the car to settle at regulatory height in the pitlane and while being scrutineered, but then moved closer to the track while in action.
Flat bottom and the rise of the turbos
The skirt ban that was introduced in 1981 clearly wasn't enough and, as the situation hit fever pitch, the FIA acted again, introducing a flat bottom for 1983 and totally removing the ground effect we'd come to know from the sport.
As we know, this doesn't stop the designers' progress as they began leveraging the gasses escaping from the exhaust, driving them into the diffuser to increase their effectiveness, something that was easier during the turbocharged era due to the abundance of waste gas being expelled.
The 80s were dominated by political wranglings as the sport also became more of a business, guided by Bernie Ecclestone as he transitioned from team owner to commercial rights owner and looked to maximise the sport's global reach.
Numerous changes were made to improve safety within the sport, be it for the driver or spectators, while the FIA started to place obstacles in the way of the turbocharged engines, which were producing in excess of 1000bhp and becoming, in turn, another safety threat.
The FIA introduced limits on the turbocharged engines, dictating how much fuel could be carried and the boost level that could be run, culminating in a 150-litre fuel tank and down to 2.5bar of boost for 1988.
1990s - F1 becomes a business and focuses on safety
The 90s began as the 80s had ended, with more restraint placed on car design along with increased safety testing and procedures, as the sport looked to increase standards across the board.
Death and risk of injury had for too long been part of the sport, leading to a sanitisation of everything from car design to track standards.
Having been banned a decade before, in 1994 refueling returned to Formula One, where it would stay until 2010, but this was just the tip of the iceberg, with the FIA also banning electronic aids. This seriously upset the apple cart as Williams had established an almost unassailable advantage over its rivals, using technology such as active suspension, ABS, traction control and launch control.
The loss of these electronic aids was significant and had a huge impact on Williams, whose technological marvel - the FW15c - was consigned to F1's chapter of cars that defeated the regulations only to cause significant change.
Difficulties for Williams aside, nothing could prepare the sport for the events that unfolded at Imola, leading to changes at the next round that would attempt to reign in the progress that had been made by the teams and slow the sport to a more acceptable level.
The most significant of these changes revolved around the introduction of the plank, limiting the car's dynamic behaviour and increasing ride height, as teams were forced to avoid wearing it beyond the prescribed limit.
Changes were also made to key aerodynamic surfaces such as the diffuser and rear wing in an effort to reduce speeds.
1995 saw a raft of changes, as the previous introduction of the plank was supplemented by further restrictions on the shape and height of the central section of the car, with a step plane added.
Dimensional constraints were placed on other areas of the car too, including the front and rear wings, both from a height and longitudinal reference point.
Further safety measures were also introduced. With the size of the cockpit template increased, the safety structure in front of the driver was now longer, while impact testing for the side of the survival cell was mandated.
In 1998 the governing body still sought to reign in the efforts of the designers, making numerous changes that were installed to slow the cars down.
The overall width of the car was reduced to 1.8m, limiting the aerodynamic surfaces available to the designers while also reducing the car's track, compromising CoG and suspension kinematics.
The mechanical disadvantages were compounded by the introduction of grooved tyres, as the FIA looked for ways to limit cornering speeds. Brakes were also placed under the spotlight to try and reign in speeds with materials, capacity and dimensions placed in the regulations for the first time.
This limited the teams to a single six piston caliper on each corner and a maximum disc diameter of 278mm and 28mm thickness.
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