A geek's guide to Porsche's secret Development Centre: part 2
Every Porsche begins at the Development Centre Weissach, but what lies within the 100-hectare site is a closely guarded secret. We take a sneak peak
Not many people know – including many employees – but since 1971, Porsche has had its own foundry.
It's housed in Building 1, just behind the former main entrance, and every weekday at 13:30 a melted metal mixture – an alloy, as the techs call it – is used to make a cast. Registering at more than 700 °C, this molten metal is poured into sand-casting moulds produced using tools developed and manufactured in the in-house model shop. Sometimes the finished products are wash-drum-sized housings for electric motors, sometimes filigree body components that are recovered from the moulds by the foundry master and his team.
Usually, these are components for cars that don't even exist yet. The in-house foundry means that prototypes can be tested at a very early stage of development with components that are of robust series quality – something that just wouldn't be possible with a 3D printing process limited to a few materials. The team constantly modifies special alloys for highly stressed components and even a small variation can have a positive effect on crash resistance, for instance, without increasing the vehicle weight.
A measure of success
The eternal objective of every aerodynamic development process is for the wind to flow perfectly around a body. How well or badly the wind flows is expressed by the drag coefficient, also known as the Cd value. To calculate this value from the measurement data generated in the wind tunnel at Weissach, the frontal area of the vehicle in question has to be recorded precisely.
The drag – and, therefore, the fuel or electricity consumption of a vehicle – is highly dependent on the frontal area. Determining this area with a deviation of just 1.5 per mille requires a special apparatus: the frontal area measurement system, which works with the principle of a shadow theatre. A light bar generated by green LEDs slowly travels twice along the entire front of the vehicle. The contour is shown on a screen positioned behind and perfectly parallel to the vehicle. A video camera films the screen and the images are then combined into a single image on the computer. From this, an image processing programme can calculate the front surface area.