From Mercedes AMG F1 team
This is the time of the year when the wind tunnels are the busiest. The wind tunnel is the heart of any Formula 1 team's development programme, where the most performance can be found in the most cost effective conditions. That means teams must be able to rely on a good, precise and accurate model to test the new car as well as new parts during the season.
The goal of the model shop is to create a 50% scale model of the car that is fit for use in the wind tunnel. Hundreds of parts, designed by the aerodynamic team, will be manufactured at the factory for the model only, all using a variety of different processes.
The reason behind the 50% scale model testing comes from the FOTA Resource Restriction Agreement, which limits full-size wind tunnel testing to four days around the year. Obviously, the situation will be different in 2012.
When operating at 50% scale, you can also make new parts faster and cheaper for testing, than with a full size car; indeed, all teams operate at either 50% or the maximum permitted by the FIA, 60% scale.
The materials that are used to build a model are different to what will be used on the car, and the processes that we use to create a model vary depending on the part. In some cases the processes are traditional machining such as lathe work and milling machines, and in other cases rapid prototyping will be used. The Rapid prototyping processes used in house are stereolithography (SLA) and Laser Sintering (SLS).
Stereolithography (SLA) uses a UV laser to cure a photopolymer into a solid part and “selective laser sintering” uses a nylon based material to manufacture parts which need to be more durable because of the high loads involved. Less loaded areas such as bodywork, floors and diffusers will made using rapid prototyping.
The advantage of the technology is to turn a computer-generated model into a physical model in a short space of time, which allows the manufacture of iterations of designs very quickly. The material differs from carbon fibre as it is much less stiff, and can therefore only rarely be used on the full size car, but still good enough for use on the scale model.
Once assembled the model will go into the wind tunnel and be tested 24 hours a day, seven days a week. It is therefore a very fluid process where alterations feed through to the aerodynamicists, are relayed back to the designers and eventually signed off for full size production for a race weekend. On average the team will test 100 new parts per day in the wind tunnel.
The model itself is a very intelligent piece of kit that has a number of applications outside of the obvious aerodynamic wind tunnel tests. It can be used to measure forces internally on the model, to measure aerodynamic load or to monitor the suspension characteristics and how it reacts with the bodywork in certain directions or pitch.