Lotus's braking attitude compensator is now illegal

[Richard]

How do you brake if there is no hydraulic line from the brake pedal to the wheel hub. I'm just saying that it makes no difference if you connect the hydraulic strut cylinder and the brake pressure line or if you have a non fluidic transmission between.

OK, lets see what Autosport has to say on the matter in the article you quoted in your OP.

However, if the drivers were changing the ride height of the cars under braking then that would be a breach of the rules.

Article 3.15 of the F1 Technical Regulations states: "With the exception of the parts necessary for the adjustment described in Article 3.18 [the DRS], any car system, device or procedure which uses driver movement as a means of altering the aerodynamic characteristics of the car is prohibited."

AUTOSPORT can reveal, however, that the adjustment to the ride height - which improves aerodynamic performance and stability on the Lotus under braking - does not come from the driver.

Instead it is reactive to brake torque and is linked directly to the suspension - so cannot be classified as a moveable aerodynamic device in the way that independent mass dampers were.

.....

Anyway, setting aside legalities, lets look at the practical consideration.

The amount of correction to the nose needs to be in proportion to the deceleration. If the system is linked to the reaction of the wheel hub to the deceleration (ie brake torque) then it will always be proportional to the deceleration of the car.

If the system is linked to the pressure of the driver's foot then the system would apply the same force regardless of the car's deceleration.

[JohnsonsEvilTwin]

So we know about the idea. But do we know who is responsible for it?
According to various reports this idea has been floating around Renault since 2010.

Now an Italian publication has it that Mercedes are at a very advanced stage with this innovation.
Bob Bell? Or did he tax the idea...?

[WhiteBlue]

If the system is linked to the pressure of the driver's foot then the system would apply the same force regardless of the car's deceleration.

I do not agree. Brake pedal pressure is proportional to brake torque. It is not a binary system where the driver slams the brake with full force and lets the computer sort out the necessary brake torque. So brake pressure and brake torque are equally useful as an input variable to a system that compensates the nose dip under acceleration. Because the brake torque is proportional to the break force its size ultimately stems from the driver input via the pedal.

The reason why the FiA sees no legality problem is because such a system fits into the parameters of a desirable innovation. It will not increase fuel consumption. It can be used in road applications and it is not excessively expensive for the other teams to adopt. It will potentially for a short time mix up the competitiveness and make the championship more interesting. You always need to look into the politics to understand why something is interpreted in a certain way. If this device had been introduced by Red Bull I would have expected a lot more scrutiny. Because it is pioneered by Lotus Renault the FiA IMO will give it the ok.

Some interesting sources for hydraulic suspension innovations:

http://scarbsf1.wordpress.com/2011/10/1 ... uspension/

http://scarbsf1.wordpress.com/2011/11/2 ... d-inerter/

Scarbs article on the Mercedes hydraulically linked rear suspension actually mentions the Honda anti dive system and says that it is activated by brake pressure.

I think we can expect a lot of work in the field of linked systems, fluid inerters and acceleration activated valves. All those systems fit well into the political landscape perhaps with the exception of the Lotus Renault inerter's use of mercury as hydraulic fluid.

If you look at the fluid inerter's design aspects it becomes clear that the mercury isn't very likely to be released into the environment due to the massive housing it is contained in. But release of poisonous heavy metals will always be a concern.

[dren]

A system that moves the suspension from energy delivered by the driver would be illegal. One that uses the energy of a moving car to do so would be legal.

[beelsebob]

That's a lovely distinction dren - good call!

[Shrieker]

With all the rumour about RB having ride height control back in 2010, i wonder whether RB had this sort of system all along from the beginning of 2010 and others (namely Mclaren and Ferrari) were napping all this time. Maybe LRGP just got the hint from them (RB)? It could explain why Mclaren or Ferrari were always just shy of the bulls even when their cars were at their best. Such a system would go so well when coupled with a flexing nose/fw/floor too. And it is a well known fact RB were (still are ?) the best when it comes to flexing parts.

[WhiteBlue]

A system that moves the suspension from energy delivered by the driver would be illegal. One that uses the energy of a moving car to do so would be legal.

Opinion of course. The Lotus system uses brake energy which is controlled by the driver and provided by the servo assist hydraulics.

[Lurk]

I'm wondering if this system could act as an ARB too? Not in the way it is actually described; it would required to link it to the direction in some way. But could it work?

Again, not a convincing answer. 10.1.2 makes no difference between rolling or standing car.

When the car is standing the loads are constant. If the suspension attitude changes while it's stationary it is not reacting to loads.
If the attitude change happens when the car decelerates one could argue it is reaction to weight transfer.

What about this solution?
When stationnary, system is preloaded on the up position. So braking does not change the pitch. When running, more forces applied thanks to DF and system goes to the lowest position. During braking, system goes back to its highest position thanks to brake pressure.

It would pass all static tests and no one could complain since "it passes the tests so it's legal" is the current way to manage disagreements.

[Richard]

WB - on that definition we can argue that everything on the car is controlled by the driver. The deflection of the wing is determined by the speed of the car, and the speed of the car is determined by the driver's right foot. So to use your logic, there is nothing wrong with a hydraulic system from the right foot to the front wing?

If that bit of "reductio ad absurdum" doesn't convince you then we night as well close this thread.

http://www.iep.utm.edu/reductio/

http://en.wikipedia.org/wiki/Reductio_ad_absurdum

[Richard]

What about this solution?

... because there is no problem to be solved?

Connect the suspension to the wheel movement and it is all resolved within the suspension system in accordance with 10.1.2.

The springs and dampers currently react to vertical movement, all Lotus have done is incorporate horizontal movement as an input. It is so simple that it was on mass produced bikes 25 years ago.

With all the rumour about RB having ride height control back in 2010, i wonder whether RB had this sort of system all along from the beginning of 2010

Good point, if a team designs a wing to be really close to the ground then it would be rather important to have a constant ride height to stop the wing hitting the ground.

I think we can expect a lot of work in the field of linked systems, fluid inerters and acceleration activated valves.

Something we do agree on! =D>

The emergence of linked front and back suspension adds further dimensions to the problem/opportunity.

[forty-two]

A system that moves the suspension from energy delivered by the driver would be illegal. One that uses the energy of a moving car to do so would be legal.

Opinion of course. The Lotus system uses brake energy which is controlled by the driver and provided by the servo assist hydraulics.

Sorry to be pedantic WB, but I understood that the brakes of F1 cars were NOT servo assisted.

Is my belief incorrect anyone?

[forty-two]

With all the rumour about RB having ride height control back in 2010, i wonder whether RB had this sort of system all along from the beginning of 2010 and others (namely Mclaren and Ferrari) were napping all this time. Maybe LRGP just got the hint from them (RB)? It could explain why Mclaren or Ferrari were always just shy of the bulls even when their cars were at their best. Such a system would go so well when coupled with a flexing nose/fw/floor too. And it is a well known fact RB were (still are ?) the best when it comes to flexing parts.

Very good point Shreiker.

This could actually explain a few things in addition to this.
- I seem to remember that the RB6 at some point (launch??) was unusual in that it had it's brake callipers mounted at the 6 o'clock position. At the time this was presumed by many on here to be in order to lower CofG, but perhaps it needed to be there in order to allow room for kit and clobber to carry out this reactive anti-dive system?
- Also on the RB6, mid season, I remember Vettel had a problem during a race whereby he reported on the radio "Loss of power" for a few seconds but then everything was fine. At the time, I believe that this was put down to his brakes having been locked on by some foreign object. After this, the callipers were moved back toward the more conventional position. Perhaps by this time they had found a way to lay things out to allow a more normal calliper position?

[hardingfv32]

The emergence of linked front and back suspension adds further dimensions to the problem/opportunity.

Then discuss these "dimensions to the problem/opportunity" instead of pointless arguing over the letter of the law that will only be resolve by the FIA with no consideration of your opinions. Are you unable to add anything to the technical discussion on this subject?

Brian

[xpensive]

The way I understand this system;

- A torque from the brake-disk applied on the upright, gives a certain movement to a tangentially mounted hydraulic cylinder.

- This cylinder is feeding another cylinder inside the push-rod, xtending the same and compensating the ride-height.

Brilliant.

Please correct me if and where I went wrong?

[forty-two]

Another thought just occurred to me on this...

Remember over the last couple of seasons, but less so in the more recent races, McLaren have been notable for porpoising when on the brakes. Could it be that they too were running a system like this, but the system took more tuning than they had expected?

We've all seen learner drivers "kargaroo-ing" whereby a positive feedback loop is setup between the driver's foot on the clutch and the motion of the car. Foot lifts from Clutch, car lurches forward and slows rapidly as engine almost stalls, foot goes back on clutch, driver "corrects" by lifting foot etc. etc. Well, what if the McLaren system was correcting for diving, but too abruptly.

Might that explain the apparent stiffness of the McLarens?