FIA reject Red Bull’s DAS protest

Mark Scott
Valtteri Bottas Mercedes

Valtteri Bottas Mercedes

The FIA has rejected Red Bull’s protest over Mercedes continued use of their innovative dual-axis steering system in Austria.

The Silver Arrows reintroduced the system to the Formula 1 world after the first day of practice got underway at the Red Bull Ring in Spielberg, but Mercedes boss Toto Wolff did say he was expected a protest to be lodged before the day was over.

That protest came from Red Bull after Mercedes topped both practice sessions with the defending champions looking like they were in a class of their own in both qualifying and race trim.

After a lengthy, lengthy wait, the governing body has now published their ruling and have rejected Red Bull’s protest.

It now remains to be seen if Red Bull introduce their own DAS system now that is has been ruled legal for this season. Red Bull boss Christian Horner did not rule out that possibility when speaking to Sky Sports during the first practice session.

Their full verdict is as follows:

‘Having considered the various statements made by the parties and listened to the expert witness statements made at the hearing, the Stewards determine the following:

The DAS system allows the driver to adjust the toe angle of the front wheels by a longitudinal motion of the steering wheel along the steering column. So the steering wheel has two degrees of freedom:

‐ Rotational degree of freedom around the steering column axis: this provides the conventional steering response of the car

‐ Longitudinal degree of freedom along the steering column axis: this steers the wheels independently from each other, thus adjusting the toe.

The DAS is hydraulically‐assisted like any conventional Formula 1 steering system, but remains under the full control of the driver at all times. Physically, the DAS is integrated with the conventional steering system of the car.

The Stewards believe DAS is part of the Steering system, albeit not a conventional one. The key challenges to the legality of DAS rely on it not being part of the Steering system. If this were indeed the case, then it would be breaching the following Technical & Sporting Regulations:

1. Article 3.8 (Aerodynamic Influence): the position of the front wheels affects the aerodynamic performance of the car, and is controlled by the driver. An exception is de facto made for steering, otherwise all cars would be illegal. If DAS fell outside this exception, it would be illegal.

2. Article 10.1.2, which states that the front suspension system must be so arranged that its response results only from changes in load applied to the front wheels. Again there is an implicit exception for steering. So if DAS was not part of the steering system, it would fall foul of this regulation too.

3. Article 10.2.1, which states that with the steering wheel fixed, the position of each wheel must be only influenced by (a) its vertical position, and (b) minor compliances. Clearly if the DAS was not considered to be part of the steering, and to hence provide an independent adjustment of the wheel position, it would be illegal. Steering is a de facto exception, and if DAS was not considered to be part of it then it would fall foul of those Articles.

4. Articles 10.2.2 and 10.2.3, related to adjustments of the suspension whilst the car is in motion or powered suspension systems.
5. Article 34.6 of the Sporting Regulations: this forbids an adjustment of suspension in parc fermé. It is, for example, not permitted to adjust the toe angle by mechanically adjusting the length of the steering arms during parc fermé. Clearly (again) steering is a de facto exception, and if DAS was not considered to be part of it then it would fall foul of this Article.

As a general conclusion, it is very simple to conclude DAS would be illegal IF it were not part of the steering system. So the main challenge and debate has to be on whether it can be considered to be part of the steering system.

The Stewards decide that DAS is a part of the Steering system.

1. Article 1.2 states that “at least two (wheels) are used for steering” and Article 10.4.1 states that “the re‐alignment of more than two wheels is not permitted”. These two articles hence limit the number of steered wheels to 2, but crucially no reference is made on that realignment being of a single degree of freedom (i.e. the LH wheel having a single function of position in relation to the RH wheel).

2. There is no direct definition of steering, but one can plausibly suggest that:

a. Steering changes the direction of the car

b. During steering the steered wheels rotate about a vertical or near‐vertical axis to change their direction, and hence steer the car.

3. Changes in toe affect the direction of the car in two ways:

a. If toe changes in a corner, the effect will be asymmetric and hence the trajectory of the car will change b. If the driver applies a steering wheel (rotational) input, the response of the car will depend on the toe angle of the wheels, hence the fore‐aft position of the DAS will have a direct steering effect.

4. Mechanically, the DAS re‐aligns the two front wheels via the same central mechanism that conventional steering does (i.e. the PAS). The fact it acts on the track rod is, we believe, entirely equivalent to the conventional steering.

5. A hydraulically‐powered DAS which remains under the full control of the driver is also entirely consistent with the hydraulically‐powered conventional steering system.

Because of the above arguments, the Stewards believe that DAS can be legitimately considered to be part of the car’s steering system, and hence that it should be subjected to the same implicit or explicit regulations as the conventional steering system.
The Stewards decide that DAS is not in breach of the suspension‐related regulations.

1. Fundamentally suspension has the purpose to insulate the sprung mass of the car from the undulations in the track surface. The alignment of each front wheel (i.e. its steering angle) has an effect on the suspension, but this is incidental. Article 10.2.1 specifically deals with this matter, stating that “With the steering wheel fixed, the position of each wheel centre…etc.”. This Article essentially separates the function of the suspension and that of the steering. It is also clear that the steering wheel position is in this case a two‐degree‐of‐freedom system.

2. Consequentially, the legality of the DAS system is identical to the conventional steering system in terms of the legality under Articles 10.1.2, 10.2.2 and 10.2.3.

3. The legality of the DAS system under other parts of the regulations (Article 3.8 – aerodynamic effect, ride height with steer (TD/003‐18), etc.) is equivalent to that of the conventional steering system as the DAS, for the reasons stated, is considered to be part of the car’s steering system.

For the above reasons the Stewards conclude that the DAS system is not part of the suspension, nor can it be considered to illegitimately adjust the suspension.

Therefore the Stewards consider DAS to be a legitimate part of the steering system and hence to satisfy the relevant regulations regarding suspension or aerodynamic influence.

In the opinion of the Stewards, the DAS system is physically and functionally a part of the steering system.

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