Illegal splitters on Red Bull, Lotus and Mercedes to be changed before the Chinese GP

There was some big news in the paddock, which involved the FIA scrutineers along with three of the top teams, but was not leaked out to the other teams. Italian magazine Omnicourse has revealed that the FIA ​​scrutineers at Sepang summoned three teams to make changes on their cars before the next Grand Prix of China, or they will be declared illegal. The three teams were Red Bull Racing, Mercedes and Lotus. During scrutineering at the Malaysian GP, the FIA scrutineers having checked the splitter that is just ahead of the underbody of the car, discovered that they was flexing more than was allowed in the regulations on those cars. In essence, the FIA ​​has summoned these three teams that raced in Malaysia outside the rules, to be within the regulatory limits in order to avoid a disqualification in Shanghai.

The underbody of a car works very closely with the front wing and splitter (feeds the air to underbody) in the front of the car and diffuser (extracts the air from under the car) on the back. This generates about 35% of the cars entire downforce.

It did not escape the eyes of Charlie Whiting's men in Australia that the cars of the top teams had a somewhat exaggerated rake angle: that is, when the car was in motion the front wing was visibly lower, similar to an abutment structure, with a lower front and visible higher rear. An abutment structure is a structure that supports the lateral pressure of an arch, similar to the at the ends of a bridge. The splitter in this case, with high pressure underneath becomes an abutment structure to support the lateral pressure of the car above it.

Comparison of rake angle in 2011 cars

The aerodynamic advantages of having a front end lower to the ground are twofold: one, it can increase the load and balance the car in the rear, and two,  thanks to the "heat" which is active between the wheel and rear bulkhead of the wing, due to the coanda exhaust channels, it ensures a greater flow capacity of air to the rear diffuser that can benefit from a greater Venturi effect thanks in part to the abutment, and that in turn generates higher grip at the rear end of the car.

The extra flexing of the splitter helps protect the wooden plank under the car that prevents bottoming out when the rake angle of the car is too high. This is possible because the splitter in the underbody, the lowest point of the car, deflects upward, avoiding the wooden plank from crawling on the asphalt of the track and wearing out more than allowed in the regulations (they are granted 2 mm of wear) which will lead to their disqualification. Charlie Whiting and Jo Bauer over time have changed their method of inspection to keep an eye on the deflection of the splitter, just to avoid the rake angle being exaggerated to gain an unfair advantage.

Comaprison of rake in 2013 cars

The news is bound to create a little bit of a fuss in the paddock. While it is usually Red Bull that has pushed the boundaries of the rules, it seems that Lotus and Mercedes have incorporated similar solutions on their cars. The effect of removing these splitters will be clear only at Shanghai and until then we can all just speculate.

We can also therefore draw the inference that it is no coincidence that the top four cars that finished the race were using illegal devices on their car, while the third team won at the Australian Grand Prix with the same device.