F1 Aerodynamic development

You may think (like I did before entering the sport) that the aerodynamic development of an F1 car is an exact science, with little waste of parts and a high return on ideas. While this can be the case sometimes, its not always that way.

All thoughts and ideas are my own and do not represent any of my previous employers.

The wind tunnel model is a different beast to the actual racing car. For one it is a 60% scale model, with a huge amount of rapid prototype (3D printing) plastics. The core of the model is a large steel and aluminium frame, which is a big difference to the carbon monocoque in (what the aero department call) the full size car. Wind tunnel testing of the full size car is no longer allowed in the regulations, so teams run a scale model (max size allowed is 60%). Here's a brief video with some more detail from the previous head of Aerodynamics (now Technical Director) Mike Elliott:

https://www.youtube.com/watch?v=9v4OrJk94Ww&t=34s

A standard wind tunnel development session will involve multiple designers and aerodynamicists developing hundreds of parts. Every 4 weeks or so, the cycle begins again developing hundreds more parts. Believe it or not, from these hundreds of parts, only a handful may remain on the car. This is due to the complex nature of these cars, a small change in one area of the car can change a development direction completely.

The detail and effort required for developing parts is monumental. Designers will work with the aerodynamicists to create the desired shape of the parts required. The CAD representation of the desired shape will initially only be an infinitely thin "skin" representation of the part known as a surface. These parts need to be legal, the legality is outlined in the technical regulations that is posted annually. The legality of the part is one of the toughest areas to master and design around, it will determine how a part is modelled in CAD and ultimately it is the driving force for the shapes created. For those who are really curious to see the regulations, here is a link to the sporting and technical regulation documents:

Once the surfaces are modelled, they will be sent to CFD to determine if they behave as expected. There could be days of work left in this to tweak the surface to get the desired results. We could end up with 5 or more "options" of these parts, these options all may look promising in CFD, but due to the limited modelling available these parts need to be proven in the wind tunnel.

Once an aerodynamicist gives the go ahead, the designer will jump back into the picture and turn the surface into a part. Depending on the structural requirements, the designer will determine the materials, how its connected to the car etc. Dealing with 60% scale parts is a different and extremely challenging role versus the parts on the full size car. Space for fixing the parts to the model is reduced, turnaround time for parts is 4 weeks from concept to on the model, multiple concepts will be run - will they all be easy and quick to change? Will they require changes to other parts to fit? These are just a small sample of the many challenges a designer faces before even looking at down force and resonance loads.

The designer will work closely with the production team in planning out sessions to ensure parts are delivered on time. Once parts have been manufactured, a huge amount of work is still to be carried out. The model tech team work on shifts to process parts. They will ensure the surface of the parts are flawless and painted, fixings are added to the parts, they check fit on the model and help in designing change plans for each session.

The complexity of the parts of a Formula One car are rarely appreciated. A lot of people see all the cars as the same. Looking at the photo below of the 2018 Mercedes (W09) if you think of each individual part as being developed separately you can get a feel for how complex a aero development program is:

Once the parts go on the model for wind tunnel testing. The wind tunnel will be used for a few days, with a program in place to test specific areas of the car. This session is lead by the aerodynamicist with extensive support from the design engineers to make sure the session runs as smoothly as possible. Only a few parts may produce the exact results that were hoped for. These parts will be a compass to lead the direction of the next wind tunnel session. The cycle begins again...

I hope you enjoyed this article, any feedback/suggestions will be much appreciated!