We meet Markus Schadow and Dr. Alexander Hennig in the BMW Group’s wind tunnel.

BMW M Magazine: Aerodynamics is one of the most important aspects of vehicle body design. Is the wind tunnel test still a highlight of development for you?

Dr. Alexander Hennig: Vehicle development in the wind tunnel is definitely a highlight for me. Even in the very early phase of development, we are concerned with the driving characteristics of what will become the finished vehicle. In the later stages, the aerodynamic measures on the first prototype vehicles become increasingly detailed. It is always a special highlight when Markus tells me that the measures worked out in the wind tunnel are having a positive effect on the racetrack.

Markus Schadow: The wind tunnel is an important tool in the development process and, clearly, we really enjoy working here. But for me personally, the highlight is testing the almost finished vehicle on the racetrack.

Which areas of a vehicle are most important for aerodynamics?

Dr. Alexander Hennig: The design of a vehicle’s front, underbody and cooling air ducts has a decisive influence. In these areas, we optimise the vehicle’s shape in the wind tunnel, sometimes to a matter of millimetres, in order to influence the flow of air in accordance with our design goals. In some places, this may mean that we make the vehicle’s shape rounder, for example, to prevent the flow from becoming detached. At other points, we deliberately bring tear-off edges to the vehicle, such as a front spoiler.

Are there any areas of a vehicle that you test more precisely for their aerodynamic properties today than in the past?

Dr. Alexander Hennig: The basic aerodynamic shape of the bodywork has improved continuously in recent decades. This makes other factors, such as the aerodynamic optimisation of the underbody and the aerodynamic design of the rims, tyres and add-on parts, all the more important today. It is in these areas in particular that much more detailed aerodynamic work is being done today than in the past.

How many hours of development time do you spend in the wind tunnel just for the aerodynamics of an area such as the front apron?

Dr. Alexander Hennig: It is difficult to break down the development time to individual components, because you always have to keep an eye on the whole vehicle. A change at the front of the vehicle can completely alter the flow around the rear – or vice versa. In general, the front and underbody of the vehicle take up 75 per cent of the development time in the wind tunnel.

Have there been or are there any vehicles that you, as aerodynamics developers, particularly enjoyed?

Markus Schadow: This is the case with the majority of our projects, particularly with special models, where you can really "let off steam" when tuning the vehicle’s set-up, due to the even stronger orientation towards racetrack use.

Our readers naturally want a glimpse into the future: which models are you currently working on?

Markus Schadow: Of course, we are not allowed to give out exact information yet. But one thing is certain: the model we are currently testing is one of the sportiest models that BMW M GmbH has to offer.

Markus, Alexander, thank you very much for the interview!