Rear Wishbones and the Magnus effect

One major change to the rear suspensions that both McLaren and Ferrari have made in their 2013 cars is incorporating the driveshaft and the track rod inside the rear wishbone. As a result, the wishbone has become much wider as can be seen in the image below.

This was first developed by Red Bull last year when they covered their driveshaft in a similar way (as seen above). The main reason behind doing this is to clear up the aerodynamics in that area so as to allow better air flow towards the diffuser. Now, how does it help in improving the aero? For that, we have to understand what is the Magnus effect.

An excellent explanation of the phenomenon is done in this video:-

As explained above, a rotating body cannot follow its normal trajectory when it experiences strong air flow. Corresponding to F1, the rotating body is the driveshaft and the air is channelled from the front of the car towards the rear. Where the problem arises is that the driveshaft’s position is fixed and hence it cannot change its “trajectory”- so if the rotating body cannot change its trajectory, then the air is diverted from its initial path. If the air is not channelled properly towards the diffuser, then the sealing effect near the diffuser will not be achieved and downforce will not be generated properly.

The gain from covering the driveshaft is not much but in F1 even a hundredth of a second matters. Alongwith Ferrari, McLaren and Force India who have the wider rear wishbones on their launch spec cars, we can expect other teams- one of them most probably Red Bull – to follow the same path.