Mercedes: Drag Reduction Device

Amidst the other updates and wet weather at the Belgian Grand Prix, one small detail that I tweeted about  went largely unnoticed by the main stream press, Mercedes AMG ran a Lotus-style Drag Reduction Device. The additional ductwork emerging from the engine cover routed up to the rear wing and back to beam wing, apes the Lotus device. This device was run again in the Young Driver Test (YDT) this week and closer images show the device departs from the Lotus design in the way it blows the rear wing to stall the airflow.
This year Mercedes were the team to first introduce a Drag Reduction Solution in addition to the conventional DRS. This was termed Double DRS (DDRS) and as first exposed on this blog, uses the opening of the rear wing flap by DRS to open a duct through car to stall the front wing. This DDRS was subsequently ruled to be legal, but a clarification of the rules for 2013 mean that a secondary use of DRS is not legal next year.
Meanwhile Lotus developed their response to the need for a drag reduction solution; their ‘Device’ has been tested but will not be raced until Suzuka. In contrast to the Mercedes DDRS the Lotus device is totally passive and solely relies on increasing airspeed to send a jet of airflow to stall the rear wing and boost top speed.
Without the scope to race their DDRS beyond 2012, Mercedes have now followed the Lotus path and developed a passive Drag Reduction Device (DRD), which is not currently in contravention of any 2013 rules.
Having explained the reasoning and mechanics behind the DRD system in the post on the Lotus Device, I’ll only explain the differences in the Mercedes system here
Luckily for Mercedes, the W03 was already designed with an intake behind the roll hoop. On the normal W03, this feeds a duct to cool the gearbox oil, on the DRD car, this gains an extra inlet to the left of the car which feeds the fluid switch and outlet ducts. So only the removable panel that forms the inlet needs to be enlarged and thus the external aerodynamics are barely changed, aside from a slightly larger inlet which may obstruct some airflow to the rear wing.


This inlet duct feeds the, as yet unseen, internal ductwork. However we can assume Mercedes have developed some passive method to divert the airflow from the beam wing outlet and towards the “L” duct at higher speeds. We’ve seen Lotus use a stepped path ahead of two outlets to alter airflow at higher speed. I suspect Mercedes have done something similar.  further suggesting there’s a complicated duct system inside , is a new hatch made in the engine cover, where we would expect the central duct to split into the two outlets.
The outlet duct that blows at lower speed also exits over the beam wing and under a Y75 winglet (Monkey seat) in a very similar manner to Lotus. The Mercedes duct is nearly circular and much smaller in cross section, although there is the suspicion the Lotus outlet duct is double walled to try to hide the genuine ductwork beneath.
The “L” duct is also similar, being merged to the central duct and then kinked to avoid the bodywork exclusion area ahead of the rear wing. However the Mercedes system first appeared to be incomplete, as this “L” duct does not reach the top rear wing. Better quality images of the system at the test, show the end cap at the top of the duct is a separate section. Attached to the “L” duct and sealed with aluminium tape. This end cap sports an opening that would blow directly at the peak suction point under the wing. I imagine this would set up the same expanding stalled airflow that the Lotus sideways blowing slots achieve on the E20. In testing the distance between the end cap and the wings underside are varied, suggesting perhaps this system is more readily tuneable to stall at different speeds in comparison to the Lotus system.
Speaking to AUTOSPORT Ross Brawn explained that tuning is the key to this system, “It’s about how you use it on track and it’s not suitable for all tracks. It has to be tuned and the tuning is a challenge.” With the device being tested over the three days at the YDT, as well as the initial runs at Spa, its possible we will see the Mercedes DRD raced in 2012. as Brawn further explained to AUTOSPORT “There is still a long way to go, there are some races later in the year where that philosophy might be quite useful”.

There is a very good gallery of images of the updated Mercedes W03 on the Auto Motor und Sport website 

With other teams rumoured to be investigating this sort of device and with no sign of a 2013 ban, we may well see more passively adjustable aerodynamics race next year or even in the remaining races.

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