How ‘PAS’ system shows Ferrari was on to DAS benefits

When Mercedes revealed its DAS system during pre-season testing, many expected its closest rivals to instantly go marching to the FIA to demand the system be banned.

But whereas Red Bull has made clear it intends to protest Mercedes when racing action resumes, Ferrari has been far more sanguine about the affair – and indeed the team suggested it had looked at and rejected the DAS idea in the past.

Some questioned whether Ferrari was simply covering its back by those comments, but investigative work has now uncovered why the Italian outfit has not been so alarmed: because it has been running a system that mimics much of the benefits of DAS since the middle of last year.

In fact, as can reveal, the concept – codenamed PAS (Power Assisted Steering) by insiders – has been so solid that it has been taken by Haas for its 2020 VF-20 car.

While PAS is not as advanced as DAS, it was this type of system that Mercedes first began running from the start of 2019 and became the precursor to what it has developed for this year.

The W10’s power steering arrangement was equipped with a double rack and pinion setu-p, creating a variable Ackermann system that made it possible to make one wheel steer independently of the other, depending on the given steering input.

In hindsight, the W10 seemed particularly agile and reactive in slow corners when compared with its predecessors, which was clearly a response to its new steering system.

This not only improved agility but also helped to keep the tyres in their optimum working range, lessening wear and improving performance.

Ferrari, having understood Mercedes concept relatively early on, decided to develop its own system, adopting PAS from the French GP onwards.

As it meant a larger, heavier and more complicated steering unit, there must have been more than one benefit to cancel out any drawbacks.

Having the ability to vary the Ackermann angle depending on the corner’s profile can have some interesting aerodynamic implications.

Given that the shape of the wake turbulence created by each wheel and tyre will also be altered according to path they draw, this could perhaps result in a similar wake profile across the board, allowing the overall aerodynamic map of the car to be tuned to increase downforce.

The timeline of the arrival of these variable Ackermann solutions shows how the introduction of DAS is an expansion of the original concept, allowing the driver to realign the steered wheels for the straights and eliminating any tyre scrub and/or drag that may occur when running even more aggressive Ackermann angles.

That Ferrari has made PAS available to Haas, proves that there must be good competitive benefits from it, and that the Italian outfit is fully comfortable with what it has produced.

DAS however, will have a limited shelf life, as Mercedes has agreed to uphold its ban in 2021 even though it’s likely that the chassis will have to be carried over from 2020.

This will come as a relief to many in the paddock who fear an escalation in costs will be detrimental to the sport in the wake of the impact caused by the coronavirus.

Haas F1 Team VF-20 front detail

Photo by: Giorgio Piola

Haas planned to use the ‘PAS’ system for 2020, with the steering assembly seen mounted to the VF-20 during testing

Ferrari SF1000 front suspension

Photo by: Giorgio Piola

Ferrari’s 2020 challenger, the SF1000, has been fitted with its ‘PAS’ system from the get-go.

Haas F1 Team VF-20 front detail

Photo by: Giorgio Piola

The Alfa Romeo C39 fitted with a more conventional steering assembly.

Ferrari SF90 front detail

Photo by: Giorgio Piola

Ferrari introduced its ‘PAS’ system at the French GP, the two different versions of its steering assembly that can be seen here alongside the chassis for comparison.

Mercedes AMG F1 W11 power steering DAS

Photo by: Giorgio Piola

Mercedes W11 with its DAS system in view, which is a secondary layer of complexity to the variable Ackermann system, allowing the drivers to realign the front wheels on the straights.

Mercedes W09 front suspension

Photo by: Giorgio Piola

Mercedes’ more conventional steering assembly was last seen here on their 2018 challenger, the W09.

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