Friday, 31 January 2020

Exploring the world of aerodynamics in the World Rallycross Championship.

“Aerodynamics are for people who can't build engines.” - Enzo Ferrari.

Ironically, Enzo Ferrari’s F1 cars were among the first to feature an aerodynamic winglet in the 1960s. Since then, aerodynamics became one of the most important elements in the design and construction of racing cars. 

In 1968 aerodynamics would change the world of motorsport as we would know it. Colin Chapman, the founder of the Lotus team, introduced the Lotus 49 at the Monaco Grand Prix featuring high mounted aerofoils on the rear suspension. By the next Grand Prix, Lotus, McLaren, Ferrari, and Brabham cars would all feature some form of rear wing, while Lotus and Ferrari went one further and added a winglet to the front of their cars.

Having seen the advantage of aerodynamics on the performance of a race car, efforts began in earnest to develop front and rear wings to increase cornering speeds without reducing top speeds as a result of drag on straights. As the 1968 Formula 1 season developed teams experimented with wings of many different shapes, sizes, and heights.

It took years for these aerodynamic designs to be regulated by the motorsport governing body, the FIA, but today, aerodynamics has become an important element of motorsport in the pursuit of an extra tenth of a second.

So, what is downforce?
Downforce is a downward force created when air moves through and over parts of an object (car). The force pushes the car into the asphalt increasing the resistance between the tyres and the road thus allowing the car to take corners at higher speeds while the driver remains firmly in control.

Formula One laid the groundwork with the introduction of various aerodynamic devices (ie. aerofoils (wings), diffusers and ground effect) in motorsport. Things soon changed when other motorsport categories: WRC, Touring Cars, Endurance, etc. incorporated aerodynamically shaped bodywork on their race cars. 

While other motorsport series captured the imagination of engineers and car designers, the 1982 World Rally Championship season captured the hearts of motorsport fans. 
1982 saw the introduction of the Group B regulations in WRC which created some of the fastest, most powerful, and most sophisticated rally cars ever built. However, after a series of fatal accidents, the Group B era was banned by the FIA. 

The monstrous Group B rally cars could no longer compete in the WRC championship and soon found a new home on the rallycross scene. Group B cars ruled the world of rallycross, but with regulation changes for the 1993 season, the Group B era was over. 

What is Rallycross? 
Rallycross is a mixed discipline combing rallying and circuit racing, held over a short lap that alternates from asphalt to gravel.

The FIA World Rallycross Championship launched in 2014 and saw 26 permanent entries battle for glory over the course of twelve rounds starting in Portugal. Since the championship's inception in 2014, it has grown from strength-to-strength.  

As the championship gained popularity, new teams signed up and in 2018, GC Kompetition founded by freeskiing champion, rally and stunt driver Guerlain Chicherit joined the championship. The French team fielded two Renault Megane R.S. RX Supercars, built by Prodrive. 

The 2019 season saw GC Kompetition claim their best result – a second-place finish at Round 8 in France. 

While many motorsport categories shy away from engaging with fans, GCK is like no other. They strive to “Change the Rules” whether it be in the paddock, business or with fans. Thankfully, we were granted the exclusive opportunity to chat with GC Kompetition about aerodynamics in the FIA World Rallycross Championship.

Junaid Samodien: Why do World Rallycross supercars need downforce?
GC Kompetition: How important downforce is depends on which circuit we are racing at - on some circuits the effects of aerodynamics are negligible, but in places like Canada it is important to ensure maximum stability and maximum top speed down the main straight. It is also vital for lateral balance through fast corners, for example in Loheac and Holjes. Their downforce is created by the rear wing which makes the car easier and more stable to handle.

JS: When did aerodynamics become important in RX?
GCK: Aerodynamics always makes a difference in motorsport, even if it's a smaller impact in World RX compared to other series. For sure when we design the car, the aerodynamics are not the first thing we think about - the initial focus is on the things that make the biggest performance gains such as the dampers, engine, brakes, etc. So these parts are developed first to make sure the backbone of the car is where we want it to be. But then, of course, the aerodynamics comes after and we work very hard to ensure our car is as good as it can be in this way.

This became even more important when Canada came on to the calendar, and suddenly aerodynamics had a shift change in importance. It is not possible to perform well in Canada if your aero isn't up to scratch - and we had possibly our strongest performance of the year in Canada which shows our work on our aero performed how we hoped! With Canada back off the calendar next year, for sure this will have an impact on how we design some of the key aerodynamic features of the car in 2020.

JS: How does a World RX team develop an aero package?
GCK: The car design is initially done on CAD, and it is possible to simulate the aerodynamic efficiency and impact 'virtually'. Then the ideal situation is to have a day or two in a wind tunnel at 1/1 scale - which is what we did with the Megane RS RX as part of its development. From here we can see if there are any issues that need changing, and fine-tune areas such as the joints between panels/doors, etc so try and make them as aerodynamically 'smooth' as possible to reduce drag.

JS: How much downforce can a World RX supercar produce?
GCK: Around 200kg.

JS: How is downforce generated on a WRX Supercar?
GCK: In various ways, but the main ones are via the front and rear splitter, and of course the big rear wing. The rear wing is especially designed with lateral stability in mind with the winglets running vertically down the main plane. 

JS: With the current freeze on aerodynamic development. How can a team tweak its aero package for a race weekend?
GCK: During the season we cannot make significant changes, so the work has to be done at the start of the season to make sure the aerodynamic package is well balanced to work across the whole year. However we can tweak some small things on a race weekend which can make a big difference, for example, the ride height, but this also affects driveability in other ways e.g. you could lower ride height to increase aerodynamic efficiency, but this could hurt on the rougher dirt or gravel sections and make the balance much worse.

JS: What areas can teams develop over the course of a season?
GCK: Many mechanical areas like dampers settings, engine management, tyre management, but in terms of aero, not much.

A special 'Thank You' to GC Kompetition and Ian Reynolds (Roots Management International) for assisting in the compilation of this story. 

Written By- Junaid Samodien
Pictures By - Wiebke Langebeck/GC Kompetition
Video By - GC Kompetition
Co-Editor - Franco Theron

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