Rear spoilers, large and small, mounted at the back of cars has been a common sight for decades. While some spoilers or ‘wings’ are more for looks than offering any real benefit, those that are installed as original equipment have usually been carefully shaped to contribute to aerodynamic efficiency and performance at high speeds.
Such aerodynamic aids were already used in racing cars but Porsche was the first company to install a rear spoiler on a production model – the 911 Carrera RS 2.7 of 1972. Back then, ‘spoiler’ may have been relatively unknown so the marketing people at the sportscar company came up with a nickname that was perhaps a bit funny but it stuck: ducktail. It was so called because its shape somewhat resembled the tail of a duck although ‘Entenburzel’ was how the Germans referred to it in their language.
BRABUS is well known for enhancing the looks and performance of Mercedes-Benz models. Thus far, since it began business in 1977, it has doe impressive work with cars with combustion engines. But with the electric age round the corner, the company has also to prepare for the future and it has begun doing so.
Perhaps because its extensive experience is with combustion engines, it has not yet developed comprehensive expertise with electric powertrains so it is not focusing on that area yet. Instead, it is enhancing performance by further optimizing aerodynamic efficiency, which can also have a positive effect on performance.
BRABUS in fact has a listing in the Guinness Book of World Records related to aerodynamics. In 1985, it refined the bodywork of a W124 Mercedes-Benz sedan and brought its Cd down to 0.26. That was a world record at the time and is still a value achieved by only a few, far more modern cars today.
Its first effort in the 21st century is with the latest EQS from the Mercedes-EQ range. Already one of the most aerodynamic production cars in the world, BRABUS has been able to lower its Cd value (the measure of wind resistance) by 7.2%.
Confirmed in wind tunnel testing, the lower drag in turn reduces the driving resistance, which makes it possible to extend the range, which the more streamlined shape increases by 7% on average in the speed range between 100 and 140 km/h.
The refinement done on the EQS bodywork with components produced from carbonfibre (with exposed structure) give the sedan sporty looks that generate the ‘BRABUS 1-Second Wow Effect’. The bodywork components can have a glossy or matt sealed finish.
The BRABUS front spoiler gives the EQS an even more dynamic face. In addition, the carbonfibre lip reduces drag, and its raised outer edges also minimize front-axle lift by 100%. This naturally also improves the handling stability at high speeds.
The carbonfibre trim for the side air intakes in the front fascia also play a role in the more striking face and route the airflow even more purposefully to the radiators and front brakes. The designers also developed carbonfibre air deflection elements installed in front of the rear wheelarches. These add some sporty lines to the sides and positively influence the airflow.
The rear end is enhanced with a diffuser and a spoiler, both made from that same hi-tech composite material. It reduces aerodynamic lift at the rear by up to 40%.
The BRABUS Monoblock wheels have been tailor-made for the wheel wells of the EQS. They are available in numerous designs and diameters from 20 to 22 inches. With the Monoblock M wheels, there is a disc design that is aerodynamically favourable.
The BRABUS wheels not only benefit the looks but also enhance handling. This improvement can be further amplified with the plug-and-play BRABUS SportXtra module which is adapted to the air suspension. It lowers the ride height of the sedan on the front by 15 mm and on the rear axle by 29 mm. This ride-height lowering also plays an important role in the reduction of the drag coefficient.
As with its other models, BRABUS offers numerous refinement options for the interior of the EQS, enabling customers to personalize extensively. The range of options includes scuff plates with backlit BRABUS logo, whose colours change in sync with the ambient lighting; BRABUS aluminium or carbonfibre pedals; high-quality floormats and a velour mat for the boot. The latter two sport the logo of the tuner and feature leather edging.
Although wind tunnels have been associated with aeronautical research and development, such facilities existed long before the first aircraft flew, and they were used by scientists in the 19th century to study airflow. Aircraft designers then used wind tunnels to see the effects of different shapes that would be used for aircraft bodies and wings.
Wind tunnels were also used by other industries and by the 1930s, as cars started to go at high speeds, the wind tunnel was used to study how air flowed over their bodies. It was a Prof. Dr.-Ing. Wunibald Kamm at the Technische Hochschule Stuttgart in Germany who was the first to use a wind tunnel for aerodynamic design studies which would be pioneering.
From then on, carmakers would add aerodynamic studies to the development process of a new model, using scale models in small wind tunnels and full-sized models in larger tunnels. Various types of equipment measured airflow so that it could be optimised because it was understood that smoother airflow could improve performance and also reduce noise levels. By having a wind tunnel, the engineers could also study the behaviour of the car design (eg stability) at high speeds without actually having to drive the prototype on the track.
In earlier years, carmakers didn’t yet have their own wind tunnels, so they used those in other research facilities. In time, some started to build their own so they could conduct testing with more secrecy and also without having to pay for renting facilities. Some built small tunnels and some built big ones, depending on how much they could spend.
Pininfarina, the automotive design consultancy, also decided to build its own wind tunnel and it was large enough to test full-sized vehicles. At the time it began operations, it was Italy’s first wind tunnel to be built for testing full-sized cars, and one of only seven in the world. That was in the year 1972 and this year sees it celebrating its 50th anniversary.
“Without a doubt, Pininfarina has a real passion for aerodynamics. And it’s a passion that has lasted more than 50 years, long before my father decided to build the structure. It all began with my grandfather Pinin, whose visionary intuition in aerodynamics is exemplified since the Lancia Aprilia Aerodinamica produced in 1936,” said Chairman Paolo Pininfarina, whose father was Sergio Pininfarina.
1937 Lancia Aprilia Aerodinamica
While it was initially used for motor vehicles, Pininfarina’s wind tunnel would become a powerful tool for testing and developing products across all sectors in which the company is fully involved. These include aircraft, high-speed trains, yachts, buildings, wind engineering, industrial design and even sporting goods. With the advent of electric mobility, there is even greater emphasis on aerodynamics as well as aeroacoustic development.
Even yachts can be tested in the wind tunnel which is 4.2 metres high and 9.6 metres wide.
It is one of the few wind tunnels in the world to have a TGS – Turbulence Generator System – able to create various conditions of controlled turbulence associated with gusts of wind, overtaking manoeuvres, cross-winds and vortices generated by cars ahead.
There is also a Ground Effect Simulation System allows reproduction of real vehicle motion conditions. This is achieved by having 4 rollers and 3 mats to allow the wheels of the vehicle and the ground to move at the same wind speed. This system was developed to make the tunnel test conditions as faithful as possible to the road conditions, and to analyze the movement of air underneath.
While most cars have closed cabins, there are also convertibles with open tops as well as the increasingly popular fitment of sunroofs that create an opening on the roof. These all have significant implications on airflow and noise generation, as those who have been in such cars will know. In the wind tunnel, the turbulence generated can be studied and solutions developed to make things more comfortable.
When it first started operation, the wind speed inside the tunnel was less than the 250 km/h maximum of today. It was upgraded with the addition of 13 fans, with each fan able to spin at a different speed or have a different blade pitch. Noise levels were also reduced allowing better aeroacoustic studies with new noise measuring techniques. Aeroacoustic tests are becoming a fundamental element for increasing driving comfort, particularly for hybrid and battery electric vehicles.
The wind tunnel is equipped with three external microphone arrays and also cameras, helping to identify the sources of noise and consequent definition of countermeasures. Noise Vision and Beam Forming support enables visualization to aid analysis. In addition, the wind tunnel is also equipped with 4 acoustic dummies for internal acoustic comfort evaluation.
“The Wind Tunnel has given our company a considerable competitive edge, being the only design company to own one. Born as a tool with which Pininfarina developed its own projects, today it’s a strategic asset for the group, thus expanding the portfolio of services that we offer to the market: an activity that supports other sectors beyond the automotive, from transportation to architecture, from nautical to industrial design,” said CEO Silvio Pietro Angori.
Car designers have long turned to the aeronautical industry for ideas that have led to innovations. In particular, the shapes of car bodies have been heavily influenced by aircraft because of the pursuit of airflow efficiency. Features today like spoilers and rear wings have their origins in aircraft design although with ‘reversed’ effects where instead of lift, the objective is to gain downforce.
For high-performance sportscars, downforce is important to keep the car as stable as possible at high speeds. This has seen all types of rear wings being installed, some very ‘distinctive’ though with questionable benefits. However, for a new rear carbonfibre wing that was developed for the Lexus LC Coupe, the company formed a long-term collaboration with world champion air race pilot Yoshihide ‘Yoshi’ Muroya to gain advances in aerodynamics that would enable them to design the rear wing.
Long and unique collaboration
Since 2016, Lexus has been reaching for the skies in a unique collaboration with Muroya, winner in 2017 of the Red Bull Air Race World Championship series. In this rare cross-industry partnership, the carmaker benefits from aeronautic technology while the air race pilot leverages Lexus’ automotive breakthroughs.
With the principal aim of winning air races, Lexus and Muroya worked together to develop championship-winning aircraft using the technology, craftsmanship and experience from Lexus. The Lexus design and engineering team has helped develop flight technologies in areas such as aerodynamics, cooling and ergonomics.
The collaboration has produced notable innovations, including a control column grip for Muroya’s cockpit that incorporates Lexus’ sensitivity technologies and a new turning manoeuvre for the aircraft based on aerodynamic data from Lexus.
The new rear wing
For 2022, the Lexus LC will sport a new carbonfibre reinforced plastic rear wing developed together with Muroya. This lightweight, highly rigid and sleek wing maximises aerodynamic performance and makes for more agile driving.
The design draws its inspiration from the wing-tip vortices that influence the design of winglets on jet aircraft. During demanding test flights with Yoshihide Muroya, Lexus engineers analysed his plane’s drag-reducing winglets and the associated vortices that are normally problematic. In the Lexus wind tunnel, engineers found that vehicle dynamics on the ground could be improved by turning the wing upside down and adding winglets.
The upside-down wing was thoroughly tested and analysed in computer simulations as well as wind tunnel studies (below).
Once computer and wind tunnel tests were completed, Lexus’ elite team of designers, engineers and Takumi artisans set to work milling an aluminium prototype. Like Muroya’s race plane wings, it was later produced in carbonfibre reinforced plastic (CFRC). Laminated in carbonfibre and epoxy resin with a hollow core, after baking in an autoclave, the woven texture is visible through the lacquered finish.
Downforce without performance loss
Long and lean, the LC’s new wing is nearly 2 metres wide, yet very durable and warp resistant. According to Lexus Takumi master driver, Yoshiaki Ito, the winglets sharpened the LC’s handling, but without using drag-creating downforce, resulting in better performance without sacrifices. The Lexus team called the car the LC Special Edition Aviation, to highlight the background to the development of the rear wing.
The carbonfibre rear wing spoiler is available (in limited numbers) exclusively with the new Lexus Bespoke Build programme. This is a special personalisation programme for customers buying a LC or LC Convertible. The vehicle will be built by an elite team of ‘Takumi’ master craftspeople at the and such units will be distinguished with a personalised interior badge installed on the centre console.
The FIA Formula One World Championship will run for the 73rd time in 2022 and as has been the case periodically over the decades, the technical regulations set by the FIA have changes. Often, these changes reflect changing economic, social or technological circumstances. The changes for 2022, which took some 2 years to formulate, were originally meant to be introduced in 2021 but because of the COVID-19 pandemic, they were postponed to 2022.
“The regulations have been a truly collaborative effort, and I believe this to be a great achievement,” said FIA President Jean Todt when they were announced in late 2019. “A crucial element for the FIA moving forward will be the environmental considerations – Formula 1 already has the most efficient engines in the world, and we will continue to work on new technologies and fuels to push these boundaries further.
However, the restriction to a US$175 million budget for each team took effect in 2021. This meant that much of the development work to meet the new regulations had to be done with the budget cap in mind. This restriction helps to level the playing field between the less rich teams and the well-funded teams like Mercedes-AMG PETRONAS and Red Bull Racing Honda which are known to have spent US$550 million and more during a racing season.
“The 2022 regulations from the FIA will create the conditions for closer racing where the cars can get closer to each other,” said Stefano Domenicali, Formula 1 President & CEO, echoing Ross Brawn, Formula 1’s Managing Director of Motorsport who said that ‘we want much closer competition. We want them battling wheel-to-wheel’.
The new regulations are expected to make racing closer, which is what spectators and fans want.
Powerplants will not change and the new generation of F1 cars will still use the same 1.6-litre hybrid V6 turbo engines. Hybrid engines were introduced in 2014 in place of the unturbocharged V8 units. The hybrid units have been complex and expensive to develop and by 2025 or so, the FIA will come out with new powertrain regulations that will use completely sustainable fuel. F1 cars currently run on a 5.75% blend of biofuel, and next year, they must use E10 (10% ethanol blend).
“Formula 1 has long served as platform for introducing next generation advancements in the automotive world. We are delighted by the momentum on sustainable fuels which perfectly aligns with our plan to be net zero carbon as a sport by 2030. Our top sustainability priority now is building a roadmap for the hybrid engine that reduces emissions and has a real-world benefit for road cars. We believe we have the opportunity to do that with a next generation engine that combines hybrid technology with sustainable fuels,” said Brawn.
The cars have evolved visually, and this is for commercial as well as technical reasons, the former being to have more appeal to spectators. The technical reasons include having to extend the front end to improve crash protection, while the rear end of the car must also be able to absorb 15% more energy. Romain Grosjean’s terrifying crash at the 2020 Bahrain Grand Prix and the way the car broke had engineers working hard to ensure that the power unit will separate in a way that will not allow the fuel tank to be exposed and leak.
Chassis strength has also been increased for better resistance to side impacts and inevitably, these changes have added weight to the car. The regulations have therefore been adjusted to allow the minimum weight to be 790 kgs, about 5% from the 752 kg limit for this year’s cars.
The F1 cars will also use bigger wheels in 2022; until now, they have been running on 13-inch wheels but next year will see them rolling on 18-inch wheels. While these may have a certain visual appeal – big wheels usually do – the drivers and engineers are not excited about this change. They have various implications on performance, including a possible increase in lap times, apart from adding weight.
Pirelli, the tyre-suppliers for F1, have developed new low-profile tyres which they say will not be as disadvantageous as the general view suggests. The new Pirelli compounds and constructions for are said to reduce the amount the tyres overheat as they slide along the track surface.
Bigger wheels, while also allowing for bigger brakes, will require close study of aerodynamics in those areas. And aerodynamic performance has always been a crucial element in the design of a F1 car. Designers in each team will have their own styling ideas for the various sections of the car while adhering to regulations, of course.
Downforce has been vital since the 1970s when people like Colin Chapman used aerodynamic principles to make the car ‘stick’ to the road more. However, in racing conditions, especially at the speeds of F1, the ‘dirty air’ from the car ahead can impact the car behind, with up to 35% of downforce being lost – even when 20 metres apart. If closer, this loss can even be as much as 47%.
The 2022 car, developed by Formula 1’s in-house Motorsports team in collaboration with the FIA, has given a lot of consideration to the ‘ground effect’ and can reduces the loss to just 4% at 20 metres and 18% at 10 metres.
Winglets are a clever aerodynamic feature on aircraft and over-wheel winglets will appear for the first time on F1 cars, along with wheel covers, last seen in 2019. While the covers can help in the aerodynamics, they have little to do with the actual tires. As a physical seal on the wheel, they will also help to reduce the dirty air coming off the car and the turbulence it causes in its wake.
The winglets will manage airflow coming off the front tyres and direct it away from the rear wing. Again, this is being introduced in the interests of reducing the negative effects on cars behind. This is expected to allow closer racing.
The 2022 car has fully shaped underfloor tunnels rather than the stepped floor used currently. This can generate and preserve large amounts of useful downforce through ground effect. As for the rear wing (which still has DRS), this also has a revised shape and position to move airflow higher up as it departs from the car so that the following car has more ‘clean air’ and can come closer.
The effects of aerodynamics on the car body and influencing how air flows over it have been studied since the 1920s. As designers came to see how certain shapes and features could reduce drag and improve performance in various ways, the styling also evolved… sometimes to extremes as with the teardrop shapes.
The quest to lower wind resistance has never been greater, especially in this age of hybrids and electric cars where every bit of resistance removed means less of the motor’s power is wasted overcoming it.
And while you might think that sportcars, with their high-powered engines, don’t really need the assistance of good aerodynamics, this aspect is even more advanced. Even the Bugatti Bolide, a concept hyper sportscar with a 1,850 ps W16 8-litre engine has many aerodynamic innovations that contribute to its ability to reach a top speed claimed to be well over 500 km/h.
Morphable outer skin
Chief among them is the Dimple Airscoop – a new technology for which a patent application was submitted a few weeks ago by Nils Ballerstein, one of the engineers at Bugatti. Since the beginning of 2020, he has been preparing a doctoral thesis project to develop a special morphable outer skin for the company’s New Technologies department – and this has now been used for the first time in the Bugatti Bolide.
The idea for the invention began in 2019, while Ballerstein was doing his master’s degree thesis. The young engineer was undertaking research for Bugatti, looking at new 3D-printed brake calipers made of titanium which cooled water as it flowed through. In order to improve the heat transfer and dissipate heat more selectively, he used a dimple pattern inside the channels. The rounded dents in the boundary layer produce turbulence – similar a golf ball.
The result was that the fluid mixes better in the channels – and the temperature in the brake caliper drops. “I was positively surprised when I saw the results with the surface patterns. I then wondered whether the same effect couldn’t be achieved with airflow,” recalled Ballerstein.
Same advantages as golf ball design
For non-scientists, the effect of the aerodynamic design is similar that that of golf balls: the dimples on the surface minimise air drag to such an extent that the ball travels about twice as far with the same impact force compared to an identical golf ball without the dimples.
The same principle applies – the dimples create turbulence on the surface of the golf ball so that air adheres better to the surface, thereby reducing the vortex flow in the slipstream of the ball and subsequently also the drag.
Ballerstein simulated test objects with dimple patterns in order to establish a factual basis to underpin his idea. After completing his master’s thesis, he stayed on with Bugatti while also starting his doctorate at the Institute of Aircraft Design and Lightweight Structures at the Technische Universitat (Technical University) Braunschweig in Germany. He sees the Bolide project as a perfect way to advance his idea.
“Everything about the Bolide is exceptional and extreme. The dimples further improve the car’s already excellent aerodynamics, thereby increasing agility and efficiency,” explained Frank Gotzke, Head of New Technologies at Bugatti.
A world first
The morphable outer skin of the intake scoop on the roof is a world first. It ensures active airflow optimisation. When the hypercar is driven at a slow speed, the surface of the scoop remains smooth; at fast speeds, a field of dimples bulges out. The 60 individual elements extend variably by up to 10 mm depending on the speed – if this benefits the driving state.
From about 80 km/h upwards, air is the dominant resistance factor, and from about 120 km/h upwards, the dimples significantly improve the car’s aerodynamics by reducing this resistance. As with the golf ball, the pattern causes a more turbulent boundary layer, which means that the air flowing around it adheres to the surface for longer and does not detach until later. As a result, the detachment and recirculation areas are reduced and the car’s cd value decreases.
In order to respond swiftly to changes in speed, the dimples extend and retract very quickly, within tenths of a second, in the same way as the active rear wing on the Veyron and the Chiron, for example.
The Bolide is an experimental study to create a track-only hyper sportscar featuring the W16 engine. No plans for production yet so it’s a superfast testbed for developing new technologies.
10% less drag
The overall result is that the dimples reduce the aerodynamic drag of the scoop by 10% and also decrease lift by 17%. Airflow to the rear wing is also optimised; at 320 km/h, the downforce on the rear wing is 1,800 kgs while on the front wing, it is 800 kgs.
Another benefit is that the lower aerodynamic drag also reduces the car’s fuel or energy consumption. “This is why the new technology is so crucial – not just for Bugatti. Optimised airflow can save energy on all vehicles,” explained Ballerstein. “We’re still in the development phase, but tests so far show that dimples improve aerodynamics, thereby reducing drag and increasing efficiency.”
Aerodynamics are one of the crucial elements in achieving high performance. Designers and engineers spend thousands of hours running simulations and then testing prototypes in wind tunnels to get the air to flow optimally around the bodywork.
This is the work of Richard Hill as chief aerodynamicist at Lotus Cars, where he has been for more than 30 years. Drawing on his experience and knowledge, the highly experienced senior engineer guided this critical element of the Evija all-electric hypercar to give phenomenal downforce. When asked how the Evija compares to regular sportscars, he replied: “It’s like comparing a fighter jet to a child’s kite.’’
The overall philosophy behind the Evija’s aerodynamics is about keeping the airflow low and flat at the front and guiding it through the body to emerge high at the rear. Put simply, it transforms the whole car into an inverted wing to produce that all-important dynamic downforce.
“Most cars have to punch a hole in the air, to get through using brute force, but the Evija is unique because of its porosity. The car literally ‘breathes’ the air. The front acts like a mouth; it ingests the air, sucks every kilogram of value from it – in this case, the downforce – then exhales it through that dramatic rear end,” explained Hill.
And what role does that deep front splitter play? According to Hill, it’s designed in three sections: the larger central area provides air to cool the battery pack – which is mid-mounted behind the two seats – while the air channelled through the two smaller outer sections cools the front e-axle.
“The splitter minimises the amount of air allowed under the vehicle, thus reducing drag and lift on the underbody. It also provides something for the difference in pressure between the upper and lower splitter surfaces to push down on, so generating downforce.,” he said.
Venturi tunnels through the rear quarters are part of the porosity. They feed the wake rearward to help cut drag. “Think of it this way – without them, the Evija would be like a parachute but with them, it’s a butterfly net, and they make the car unique in the hypercar world,” the engineer explained.
To have active aerodynamics, the Evija’s rear wing elevates from its resting position flush to the upper bodywork. It’s deployed into ‘clean’ air above the car, creating further downforce at the rear wheels. The car also has an F1-style Drag Reduction System (DRS), which is a horizontal plane mounted centrally at the rear, and deploying it make the car faster.
Lotus pioneered the full carbonfibre chassis in Formula 1, and the Evija is the first Lotus road car to use that technology. The chassis a single piece of moulded carbonfibre for exceptional strength, rigidity and safety. The underside is sculpted to force the airflow through the rear diffuser and into the Evija’s wake, causing an ‘upwash’ and the car’s phenomenal level of downforce.
The Evija is set to be the world’s lightest EV hypercar but weight does not actually affect aerodynamic performance. Hill said that the car’s weight has no effect on overall aerodynamics. However, the lighter the car, the larger the percentage of overall grip is achieved through downforce and the lower the inertia of the car to change direction.
Richard Hill’s full title is Chief Engineer of Aerodynamics and Thermal Management, and he has worked at the company’s Hethel HQ since 1986. His role involves collaborating with the exterior designers of all new Lotus vehicles, from the early concept phase of a programme through to testing pre-production prototypes.
For decades, car designers have understood that aerodynamics play a key role in a vehicle’s performance in more ways than one. The better the aerodynamics – usually referencing its coefficient of drag or Cd – the less wind resistance it has. This, in turn, can benefit fuel economy as less power is needed to achieve a desired speed, reduce wind noise and also enhance stability.
Over the years, various shapes have been conceived with the aim of lowering the Cd number as much as possible. The vehicles have looked strange in some examples but usually had typical features such as a sleek bodywork and sharp nose to ‘pierce’ through the air.
Few have been more radical than the Aerodynamic Research Volkswagen (ARVW) of 1980, a single-seat arrow that remains the most aerodynamic vehicle ever built with a VW badge. Sparked by the oil crises of the 1970s, the ARVW was meant to demonstrate how aerodynamics and lightweight vehicle construction could generate massive speeds from everyday power.
The first challenge was squeezing a driver, powertrain and four wheels into a body that could have the smallest profile possible. At just 84 cm tall and 110 cm wide, the ARVW’s shape was optimised for aerodynamic smoothness. Its wheels were hidden wheels and a smooth underbody allowed air to pass under the vehicle without turbulence. There were even moveable fins that helped keep it stable at high speeds.
The ARVW was built from an aluminium frame under a fibreglass-and-carbon body. Power came from a 2.4-litre turbocharged, inline-six engine which produced 177 bhp. Set right behind the driver, it powered the rear wheels via a chain drive. By using an onboard water tank that injected water into the turbocharger’s intake, the engine needed few cooling vents. The main cooling vent was positioned in the nose to let air flow smoothly over its radiator and exit on top of the vehicle.
The ARVW’s Cd was 0.15, a number that remains far sleeker than any production vehicle. In October 1980, a small team of Volkswagen engineers and a skilled driver went to the Nardo test track in Italy to demonstrate what the ARVW was capable of. In the first hour, the ARVW hit 355 km/h., eventually reaching 362 km/h, setting two world speed records in the process.
Volkswagen built 200 units of the XL1 for sale between 2013 and 2016.
The shape of the ARVW would later be referred to in the radical XL1. And as low drag coefficients provide sizable benefits to an electric vehicle’s range, advanced aerodynamics will play an essential role in Volkswagen’s the upcoming ID. electric vehicle family.
Nobody can see it, but it is a factor in a car’s fuel consumption, safety and comfort. It’s called aerodynamics, or the study of how air moves around solid objects. In the automotive world, its application is very practical: reducing a car’s resistance to wind. And all this is tested in its ‘temple’, the wind tunnel. This is how it works.
A hurricane in the room
Typically, prototypes are placed in the middle of a chamber, securely kept to the floor. Huge fans generate airflow and the vehicles can face winds of up to 300 km/h while sensors study their individual surfaces.
The air travels in a circular motion, depending on the size of the rotor and blades. Needless to say, when it’s blowing at full power, no one will be allowed inside the chamber as they would literally get blown out of it.
The car’s resistance data is displayed on the computer screens. Hundreds of numbers to be interpreted and compared to even the smallest variable to improve aerodynamics. Every millimetre of each part is key, since it is not only possible to reduce consumption, but also to increase stability, comfort and safety.
Shaping to go faster
Wind tunnels, while primarily used for development of future models, are also valuable for racing cars. While the goal in aerodynamic efficiency for production models is to lower fuel consumption and improve stability, when it comes to racing cars, optimising the bodywork to achieve higher speeds is the aim.
The performance of rear wings, for example, can be optimised for the best downforce.
CUPRA Racing’s Head of Technical Development, Xavi Serra, explains: “We want the new CUPRA Leon Competicion to have less air resistance and more grip when cornering. First, they will have to compete against the wind. Here we measure the parts on a 1:1 scale with the real aerodynamic loads and we can simulate the real contact with the road. This gives us the result of how the car will perform on the track.”
235 km/h standing still
The facilities where the CUPRA engineers test their prototypes are among the most complete and innovative. They have a special feature that makes the tests seem as if they are made in near-real conditions. However, instead of the car travelling at up to 235 km/h, the same effects are achieved by making the air travel at those speeds.
“The most important thing is that we can simulate the road. The wheels turn thanks to electric motors that move belts under the car,” said Wind Tunnel engineer Stefan Auri.
After hundreds of measurements, the results are compared with the car’s previous generation. “In this sense we’re satisfied; we’ve lowered the drag and improved the downforce, so it’s more efficient than the previous model, which will give us better lap times on the track,” said Xavi, adding that the data obtained will also be used to improve the new CUPRA models.
Supercomputer crunches numbers
The wind tunnel is not the only tool for improving aerodynamics. Supercomputing also plays a key role. When a model is in the early stages of development and there is not yet a prototype to study in a wind tunnel, 40,000 laptops working in unison are put to the service of aerodynamics. This is the MareNostrum 4 supercomputer, the most powerful in Spain and the seventh in Europe. Scientists around the world use it to carry out all kinds of simulations, and in the case of a collaboration project with SEAT, its computing power is used to battle the wind.
