FIA race stewards have rejected a protest by the Lotus F1 Team against Mercedes' innovative 'double DRS' rear wing system, after hearing arguments from the opposing teams on Thursday. The protest, lodged by Lotus yesterday afternoon in Shanghai, follows two races of controversy over the system, with the FIA's scrutineers already having twice declared it legal.

Mercedes double DRS system involves a complicated system of piping that connects the rear wing to the front wing. The the driver activates the DRS during practice, qualifying or the race, the rear wing movement uncovers two holes in the rear wing endplates, allowing air to flow from the top of the rear wing down to the underside of the main front wing elements.

In similar style to the rear wing F-duct that was pioneered by McLaren in 2010, this airflow then stalls the front wing elements, reducing its drag and further increasing top speed. The system has the secondary effect of reducing downforce at the front wing also, thereby improving the balance of the car.

At Thursday's hastily-arranged hearing, Lotus argued that Mercedes' system should be declared illegal because it depends on driver movement for activation, i.e. the pressing of the DRS button on the steering wheel. However, having examined detailed drawings of the system, the stewards were satisfied that it was entirely passive and adhered to the primary purpose of the DRS 'improving overtaking', therefore making it legal.

“Having examined the evidence presented, the Stewards DECIDE unanimously that the Protest is DISMISSED,” read the stewards' decision.

“There are many different parts of bodywork fitted to cars from a variety of teams, which have been designed specifically to take advantage of the change in airflow caused by the activation of the DRS. The modifications on Cars 7 and 8 are examples of the above.

“The design is entirely passive and has no moving parts whatsoever.

“The sole purpose of the "DRS" (or the "system" as referred to in the regulations) as stated in Article 3.18.3, is to improve overtaking. The Mercedes design is completely consistent with this objective.”

The stewards also pointed to approval from the FIA of Mercedes' double DRS earlier in the year as another reason to throw out the protest.

“Further, and distinct from the grounds above, the protest is dismissed on the grounds that the FIA confirmed the assertion of the Mercedes team that it had ... sought clarification from the FIA Formula One Technical Department concerning this matter and the FIA confirmed that the Mercedes design had been deemed permissible.”

Lotus were reminded of their right to appeal the stewards' decision, but has decided against such action. This is sure to spark a frantic scramble among the top teams to develop their own double DRS designs.

McLaren's technical director Paddy Lowe admitted earlier in the week that clarity was needed on the legality of the system before they developed their own.

“Until we've got clarity, it's difficult for us to make a huge amount of effort in that direction,” said Lowe. “That's really where we're stuck at the moment.”