The shapes of things to come
In their perennial search for elusive hundredths, Formula 1 teams have embraced an unusually broad range of technical solutions this season. Here’s a glimpse at – and beneath – their cars’ carbon skins
Another season, another new batch of Formula 1 cars, each embodying the hopes and aspirations of their teams. Collectively, they carry the hopes of the sport’s fans for a great season despite the many challenges it faces, perhaps the greatest of which is the smart virus called downforce.
Ever since 1968 F1 has been struggling to deal with this phenomenon. What makes F1 the perfect breeding ground is that downforce thrives on money and competitive intensity. Rules and regulations have been devised as vaccinations but it simply adapts, reappears in another form as brilliant minds and vast resources find ways of growing the culture anew in F1’s petri dish.
We’ve learned to live with it and in 2017 the sport even legislated in more of the stuff for the first time with wider cars (and tyres to translate it all), greater bodywork freedoms between the front axle and cockpit area and bigger underbody diffusers. Into the second season of these rules, greater convergence of design might have been expected. But in fact we’ve got quite the opposite, with quite the most divergent array of ways to create downforce that we’ve seen for some time.
The randomiser in this case would appear to be that other major challenge to F1’s popularity – the cockpit halo. It’s an intrusive piece of kit in more ways than just its ugly visual imposition on the fan’s idealised picture of the sport. It also places weight in exactly the wrong place of the car – high up, increasing the centre of gravity – and is an aerodynamically bluff surface in a critical part of the car’s airflow.
In response to the halo’s burden, the smart virus has adapted as its agents – those in the laboratories of CFD departments, wind tunnels and design offices – have sought out new airflow pathways. Because the halo has added about 15kg high up, there has been a total reappraisal of where radiators, intercoolers and so on are placed as designers try to pull that c of g height back down. This of course has had major implications upon the aerodynamic surfaces and the greatest variation evident is in the shapes of the sidepods housing these components. So we have high radiator inlets and low, with differing front suspension layouts to suit. We have severe undercuts on some, fat flared-out pods on others. We have thin sidepods and wide ones, extreme coke bottle plan views and other, broader waists. Some radiator inlets look like letterboxes, others like tear drops. There has been a general move to smaller inlets to compensate for the frontal area increases brought by laying the radiators down in search of lowering the c of g. But the engines still need cooling and so, in further compensation, the engine cover inlets have become bigger, no longer just airboxes for the engine’s inlet air but internally divided into additional compartments for cooling. Smaller sidepod inlets have also meant bigger outlets at the back, the pressure differential effectively sucking the air through harder, increasing the cooling effect of the airflow over the radiators by increasing its speed.
Amid all that variation, we still have the same fundamental divergence of aerodynamic philosophy as last year between low-rake Mercedes – and high-rake everyone else.
Within the massively intricate prescription of regulations that has arisen as an attempt at containing the virus, creating downforce is no longer just a matter of good aerofoil wing profiles and a hard-working underfloor diffuser. For several seasons, it has been a spinning-plate exercise in vortex generation as simulation of immense computing power has shaped multi-contoured vanes and slots that induce circles and tubes of air. These interact with each other to energise the airflow over the car’s whole surface. The faster it can move down the car and over the back, the harder it works the rear wing, the more it helps pull the airflow from the underbody through the diffuser.
Counter-rotating vortices are deliberately set up with just a small gap between them, sucking the air through that gap with immense force, making it move faster over the downforce-inducing surfaces, with vanes and flip-ups directing it towards and away from the relevant areas. The connections between these slots, vanes and flicks are intimate and intricate. Hence those multiple-planed front wings of immense complexity are not so much direct downforce generators as flow management devices that set up the relevant vortices down the car.
Nothing is ever unlearned and so, although flat floors were legislated in 1983, ground-effect is induced regardless. Today, instead of the banned skirts to seal the air within the floor to create a vacuum, we have airflow skirts instead – vortices of air that propagate down the outer edges of the floor, preventing the oncoming flow from escaping out the sides. Air controlling air.
Another re-routing of the virus puts exhaust blowing – which has been in and out of use since being invented in 1983 – back in the headlines. Yes, it was ostensibly banned in 2013 but here it is again anyway. This time it’s the rear wing underside rather than the diffuser that is being blown, the hot fast-moving air accelerating flow there to increase the pressure differential between the wing’s top surface and its underside, thereby pressing down harder upon the car. Last year teams were using the ‘monkey seat’ winglet to join up the whole combination of exhaust/monkey seat/rear wing, with the plume influencing the airflow above it to head towards the wing. So for this year the FIA introduced new dimensional requirements, moving the exhaust back and limiting the size and placing of any winglet. So instead the exhaust is being pointed upwards at the maximum permitted angle of 5deg and blowing directly. Although the engine software that induced exhaust blowing in the V8 era is no longer permitted, the ERS-h of the hybrid engine allows the exhaust to be manipulated at the crucial moment. This motor – which runs on a shaft between turbine and compressor – can be spun electrically off-throttle to enhance the exhaust flow or match up the engine rpm with the turbine rpm. Everyone is almost certainly doing it, but Renault drew attention to the practice in testing by fashioning its wing underside in heat-resistant bare aluminium rather than the previous carbon fibre.
So that’s the environment in which the downforce virus is currently flourishing. Here’s how each team has incorporated it.