DAS Dual Axis Steering...Legality??

[bosyber]

Not that much, as his argument seems to bottle down to him, as an aerodynamic guy being unable to believe that a team would be tricky for anything but aero effect (tool:hammer - see nail in everything).

Steering clearly has an aerodynamic effect on the whole car, it's just that it is fundamental to driving, and thus the one (apart from DRS) allowed way that aero may be influenced on track. As long as the argument holds that this is just steering, Newey has an irrelevant point.

[henry]

rules about the steering or rules about the suspensions?

Rules about suspension elements. There are allowed to be up to 6 elements per wheel. My expectation is that these are: two for the upper wishbone, two for the lower, one push or pull rod and one for the track rod (steering arm). The regulations don’t specify these and other configurations that meet these rules would have to be allowed.

IMO Steering is an alignment function using elements of the suspension not a separate physical system. The rules allow re-alignment using this function. The rule writers didn’t expect that the re- alignment might be change in toe. They do now and have written this option out of the 2021 regulations.

I agree with your expectation.
However I'm still interested to see if other teams can come up with some fresh ideas given the alternative interpretation in place for 2020. Often the first person/team to innovate does not receive the long term benefits of the innovation as another team takes the idea and develops it better.

I’m responding in this thread as it’s more appropriate.

The 2021 rule, below, restricts the distance between the end points on the rack and only allows alignment control by rotational movement of the steering wheel.

I think it be could be interpreted to allow a DAS that increases toe with steering wheel rotation by moving the end points in planes at right angles to the bulkhead. @Scarbs suggested this as the mechanism in his earliest notes on DAS.

It may be that something else in the rewrite of the suspension rules would restrict this. The 2021 suspension rules are as restrictive in their way as the aero rules, attempting to remove all but the simplest of functions in the time domain and reverting to a system similar to a 1953 Morris Minor that I used to own.

10.5.2 The re-alignment of the steered wheels, as defined by the position of the inboard attachment of the relevant suspensions members that remain a fixed distance from each other, must be uniquely defined by a monotonic function of the rotational position of a single steering wheel.

[bluechris]

Its aero altering.

The air that hit the wheel with toe-out travels differently to the back of the car than the air that hits the wheel with 0 or anything different in toe setting.
Mercedes can have different sidepods or anything in the car counting the air with 0 toe in the tunnel and in simulations and gain from it in the straights where you don't need toe.
No other team can do that and its the only thing that maybe will ban the system till Melbourne.

Its legal so far because all the discussions are about steering wheel rules and suspensions and not about aero to fia side.
The only way it will be permitted is because the other teams don't really believe they will win again this year from what they saw in Spain, so by not protesting about aero much is giving them the benefit to make accusations the whole championship about DAS and save their face because Mercedes with or without it, have a winning car again and kudos to them for this.

[SiLo]

Just because the side effect is that it changes aero - doesn't mean it's the primary reason.

I'm not even sure why there is so much discussion. Other teams of course are going to call it illegal, but a look at the rules and what it does mechanically, its pretty obvious it's going to stay for the season.

Literally just another axis for steering. Toe not included in suspension setup, not automatic or controlled by a computer, powered by the driver, wheel not fixed while toe changed... the list goes on.

[AJI]

Not that much, as his argument seems to bottle down to him, as an aerodynamic guy being unable to believe that a team would be tricky for anything but aero effect (tool:hammer - see nail in everything).

Steering clearly has an aerodynamic effect on the whole car, it's just that it is fundamental to driving, and thus the one (apart from DRS) allowed way that aero may be influenced on track. As long as the argument holds that this is just steering, Newey has an irrelevant point.

I fail to see how his point is irrelevant? If the driver is altering the aerodynamics of the car with a device in any other way than that which is prescribed in the rules has a point. The car doesn't need to alter the toe for steering when going in a straight line but it helps, with tyre scrubbing and aero. It's simultaneously a 'legal' tyre control device, and also an 'illegal' aero device.

[Airshifter]

Only time will tell if this system is allowed through the season. At this point I'm leaning just very slightly towards it not be allowed, on the basis of moving aero. Since the use is not when turning the steering wheel, and not intended to steer the car, the biggest change it makes when implemented on the straights is to change the aero wash over the wheels.

But the FIA have not been consistent with the use of the "moving aerodynamic device" regs at all, so it's up in the air really. After all the use of the Renault mass damper was to keep aerodynamic devices from moving as much as they had without the mass damper, yet it was banned. POU moves the nose down, yet has been limited but allowed.


In any case, pure genius by Mercedes for developing it. I'm sure they have covered all bases to be able to switch quickly to not using it just in case it is banned. And I suspect that those changes would also include a host of small aero changes on the bargeboards, wheels, brake ducts, etc.



But many thanks to the exhaustive debate over DAS on the W11 threads. Even having viewed all the quoted regs, arguments for and against, opinions on how it will go, etc..... I'm still quite on the fence as far as how the FIA will rule.

[cooken]

Nobody knows except Merc if the biggest change is aero (drag), tyre temp, or rolling resistance. I'm no aero expert but I can't see the change in toe having much effect, certainly not so much that it could be construed as the primary function.

I find myself asking why was the 2021 clause added if the current regs are sufficient to prohibit this system?

[nevill3]

I personally think the main purpose is to overcome the compromise teams have always had to make regarding optimum toe for cornering and handling and optimum toe on the straights where much less toe was desirable.

After driving normal road cars with incorrectly set toe angles and correcting them the handling improvements were very noticeable. Having the ability to alter this with such a simple modification will give increasing benefits to Mercedes as they learn throughout the season.

The aero argument should not be enough to ban this in my opinion but this is the FIA were talking about so we will have to wait and see until after scrutineering in Australia

[ncx]

Since the use is not when turning the steering wheel, and not intended to steer the car, the biggest change it makes when implemented on the straights is to change the aero wash over the wheels.

If "steering" means the control of the direction rather than just a change of it, they could argue that their system is there to improve stability on the straight, even though it's pretty obvious that there are actually other reasons.

In any case, pure genius by Mercedes for developing it. I'm sure they have covered all bases to be able to switch quickly to not using it just in case it is banned.

Imo, the MB DAS is hardly a ground-breaking innovation. Surely MB are not the first to think of adjusting toe on the go, as static settings require a compromise between straight and cornering. An OP in the W11 tread has also provided images/link to a road car that had this capabiliy over 10 years ago. It's just a question of whether MB managed to implement it without breaking the law by the letter of it. (Btw, the use of longitudinal movement of the steering wheel as a mean of control in a racing car was already present in Japanese cartoons originally dating back to the 1970ies, though in that case it is used to change wings AoA )

It's gonna be entertaining. It may not be very easy to keep it if the "unintended consequences" are far more relevant than the declared primary objective, that is, "steering".

[henry]

This post about 2021 was raised in the W11 thread, I thought it better discussed here.

Can someone can help me interpret parts of this rule better:

10.5.2 The re-alignment of the steered wheels, as defined by the position of the inboard attachment of the relevant suspensions members that remain a fixed distance from each other, must be uniquely defined by a monotonic function of the rotational position of a single steering wheel.


Does this prohibit moving the wheel ends of the steering arms up and down to push/pull the wheels in and out to change the toe angle?

Does this prohibit building a steering wheel bracket that would simulate the current push/pull activation method for the system?
- This one I think limits any z-axis movement of the steering wheel, due to the word "monotonic".

The second part of the rule seems easier to understand than the first part. I assume monotonic means that if you implemented push/pull passively via rotation (kinda like turning a screw), then it's no longer monotonic. However, the first part of the rule confuses me a bit. It only refers to the inboard attachment, meaning in the monocoque. Vertical motion (like flapping a wing) would replicate the same effect, assuming you has some kind telescoping end on the wheelside joint. Such a joint could potentially have the telescopic motion keyed so that telescoping is only allowed under certain steering angles, or more likely loads. That doubt leads me to think that we might not see the end of DAS come 2021.

This rule wouldn't prevent moving the wheel ends of the steering arm but I’m not sure how you’d do that and you can achieve the same effect by moving the inboard end of the steering arm.

The word rotational is the one that restricts the Z movement. Monotonic simply means that the angular movement wheels must follow the angular movement of the steering wheel, the incremental direction of the wheels can never reverse.

The reference to inboard attachment is to the ball joints at the ends of the rack.

But I think you’re right some form of cam arrangement, driven by the rotary motion of the steering wheel, that simulates the Z movement currently exercised by the drivers would be allowed by my reading of these rules. It would be similar effect to Ackerman but I think more tuneable.

[vogonvader]

Just because the side effect is that it changes aero - doesn't mean it's the primary reason.

I'm not even sure why there is so much discussion. Other teams of course are going to call it illegal, but a look at the rules and what it does mechanically, its pretty obvious it's going to stay for the season.

Literally just another axis for steering. Toe not included in suspension setup, not automatic or controlled by a computer, powered by the driver, wheel not fixed while toe changed... the list goes on.

If Mercedes accepts there are aero effects, be it primary or not, that I think compromises the legality of DAS as you don't need no toe-adjustments to go through a straight. No aero effects when steering into and out of a corner are the the main goal in steering. Any effect gained by DAS is a main goal in this sense that the toe-adjustment is not needed.

[stevesingo]

My view is that this has been designed primarily to counter the negative effects of POU suspension geometry. The advantages of POU are well understood I think, lowering of the car with steering angle applied by means of effectively increasing the distance between pushrod ends. The negative aspects are, the effects bumps have on the steering hand wheel emphasised by the toe out attitude of the front road wheels and the mass and aero forces actin vertically on the suspension will, at anything other that straight ahead, want to turn the steering hand wheel. Being able to place the front road wheels in a more neutral position will likely go some way to negate this.

Sure there might be an aero benefit, but such is the turbulence from a front wheel, I'd expect this to be negligible. And, sure there will be a tyre wear/temp effect. Less wear is a good thing, although most circuits are rear tyre wear limited. Less temp, may be debated, dependant on the baseline front tyre temp.

[izzy]

it was obviously supposed to be illegal, but Mercedes spotted a loophole in the wording, i.e. "IF" the steering wheel is fixed, and FIA have been consulted, done the decent thing with the cars already being designed to those rules, accepted the loophole was there, and closed it for next year. Gorgeous F1! Thank god it's not quite a spec series yet

[SiLo]

it was obviously supposed to be illegal, but Mercedes spotted a loophole in the wording, i.e. "IF" the steering wheel is fixed, and FIA have been consulted, done the decent thing with the cars already being designed to those rules, accepted the loophole was there, and closed it for next year. Gorgeous F1! Thank god it's not quite a spec series yet

How they should do things. Allow the looohole for the year and then close it. I enjoy seeing innovations that at least see a season out than ones that never see the light of day


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[Sieper]

What I don't understand is any moveable aero is forbidden.

With toe-in your wheels have a larger frontal aero surface then with toe neutral. So by moving the wheels to toe-neutral you are having less of an aero impact and as such it is moveable aero. They way how you achieve it does not really matter anymore. The fact that you have a way of controlling it to your suit is enough to call this moveable.

Then, to make matters worse, there is the way you control it, yes you use the steering wheel, but not to steer, just to actively control the aero frontal impact of the front wheels. When pulling the steer toward you and when pushing it away you are not steering at all, you are moving in a straight line. The only purpose is to change toe-in and with that frontal aero surface is reduced.