Lotus's braking attitude compensator is now illegal

[dren]

It is the FIA rules and limitations that have prompted the Lotus approach.

What past FIA rules would have prevented the implementation of this system until now, 30 years after it was first used on motorcycles?

Brian

There might not have been reasonable gains seen from it in the past.

[hardingfv32]

Actually powering by external devices is prohibited among other things.

Not arguing, but have you actually seen that stated in the rules?

Brian

[Ian P.]

Pretty straight forward and concise, directly from the Technical Rules.

10.1.2 The suspension system must be so arranged that its response results only from changes in load applied to the wheels.
10.2.2 Any powered device which is capable of altering the configuration or affecting the performance of any part of the suspension system is forbidden.
10.2.3 No adjustment may be made to the suspension system while the car is in motion.

What Lotus has done is a self energising ride height adjustment.

Why was it not needed previously, you had refueling which reduced the range of loads the suspension had to be able to handle. Before that there was active suspension, no Parc Ferme, driver adjustable systems and the cars were lighter.
Now you need suspension to work (optimally we would hope) with full fuel tanks, greater car weight, marginal tyres and do it all from qualifying to the last lap.
My guess is we will see this widely used in 2012 and banned in the future.
"No interraction between braking and suspension system components permitted, mechanical or otherwise".
Let the games begin .....

[WhiteBlue]

My guess is we will see this widely used in 2012 and banned in the future.

It certainly is one possible outcome. On the other hand clever suspension development is something most top teams and the FiA support. Movable aero devices were prohibited as well and now we have DRS. It can also end with some of the more restrictive suspension paragraphs being deleted. I don't think that powered devices will be allowed in 2013, but connected hydraulics operated on parasitic power and controlled by inertial forces should be something that may have a future.

I could even think that powered devices will return in some shape or form in some years time. If they want to be more energy efficient - as the PTB want - they need to exploit ground effect more. The teams are reluctant to move to a tunnel configuration so a step between could be stepped floors with active ride height of some form.

From 2015 the FiA/F1commission always has the option to reduce power further by tighter restriction of the fuel limit. That way they gain some lee way for performance enhancing suspension systems that was not available in 1993. So depending of the political debate we could see a lot more of this.

[xpensive]

It seems to be pretty simple in essence. When break pressure is applied a part of the oil goes to a small cylinder which elongates the front suspension strut.
...

Have you changed your mind WB, please elaborate?

Either way, I would be surprised not to see similar "anti-squat" devices for the rear suspension as well, now that he principle as such has been declared legal.

[timbo]

Either way, I would be surprised not to see similar "anti-squat" devices for the rear suspension as well, now that he principle as such has been declared legal.

Not mach reason doing so as max acceleration of F1 car is nowhere near max deceleration.

[Reca]

In the current issue of Autosprint there's an interview with Luca Furbatto (new STR designer, coming from McLaren), here my translation of his quotes, between each paragraph there's journalist's reasoning that I omitted, just added some parts in brackets if required to better specify the context:

These systems [to increase braking stability] are around since years but the realization is quite tricky, if we are talking about devices transferring fluid between front and rear of car: braking time is usually rather short, in the order of 3-4 tenths. That's why so far have been scarcely adopted.

It seems to me [Lotus system] exploits the braking torque to raise the car. Thus everything is 'contained' in the front axle and for this reason it could be more effective. There could be still shortcomings though. In order for the system to work, something has to move. If it's the caliper, it doesn't seem a great idea to me, what you gain with ride height you lose in stiffness and efficiency of system.

This makes me think that it's more likely related to kinetic movement of suspension than to the moving caliper. While in straight line the two upper arms of suspension are working in compression, lower ones in tension. When braking starts these forces change and changes also the caster. By exploiting these forces it's in theory possible to move an actuator that then works on the pressure of the hydraulic system. We're talking about few millimeters of movement, that opportunely amplified can give even five cm of ride height increment. Important is for the system to be passive, meaning activated by an external cause and not by the driver.

IMO a legal system was the one I was talking about at the start, fully enclosed in the car's body. I don't know on which basis this one was declared legal. Maybe they think that brakes and suspensions aren't part of bodywork. IMO there could be protests.

[The advantage] is being able to use lower front ride height. I don't think it's related with quite noticeable rake as seen last year on the Red Bull. The RB7 would stay lower on the front at high speed too. The suspension travel wasn't different from other cars. The only advantage I see, theoretically, is being able to ride kerbs with a softer car without suffering from that in other parts of track.

IMO it can't make a similar difference [equivalent to DDD or EBD]. First, at the moment the potential of downforce generation from front wing is very high. With ban of exhausts blowing in the diffuser the high potential load at the rear end is lost, so from the front there's even too much. It's not necessary to get close to the ground. Last year RB was doing it as that was only way to get enough front end downforce to balance rear's. Now you would get a constantly oversteering car, too biased on the front end. IMO we are talking about 1-2 tenths at best.

[WhiteBlue]

Have you changed your mind WB, please elaborate?

I have not changed my mind regarding the nature of the reactivity of the system. Indirectly the attitude or pitch compensation is activated by the braking action of the driver and the connection is quite closely linked. Lotus are said to have used the break torque which is proportional to the brake pressure. I think there may be other means of using it like Luca Furbatto indicates.

Initially I have thought that Lotus used brake pressure with some kind of hydraulic amplifier to make the system work. I still think that this might be also legal as long as the hydraulic amplification stems from a parasitic power source and not from an active system.

I also agree with Furbatto that the systems may be legally challenged as soon as we start to see them impacting on performance. There are just too many old paragraphs around that were introduced to fight active suspension and aero devices working on suspensions. Hopefully that situation gets resolved in the not too distant future.

There is little reason to ban clever suspensions nowadays. In 1993 it was primarily done in order to curb performance and ban driver aids. Both reasons are not valid any more. The torque control of the automatic systems from 1993 is now well prohibited by the control the FiA imposes on the standard ECU. So we do not need to fear that ABS and torque control could slip in again. The performance curbing is now well in hand by the engine freeze and the future ability to reduce fuel flow when needed.

Hence it is now the time to think about de regulating the suspension rules. Perhaps it is still not wise to use systems with active pumps and full computer control of the ride hight on all four corners of the car. But reactive systems should be completely liberated IMO.

[scarbs]

Here's a rough schematic of the Lotus system

[hardingfv32]

Why do we need this system that improves braking performance. Current braking performance adds nothing to the 'show'. There is no differentiation between the drivers with the current short brake zones. The show would be much better if the braking was more challenging for the drivers. I say bring back steel brake discs!

Brian

[xpensive]

Here's a rough schematic of the Lotus system

There you go Scarbs, this position for the master cylinder makes a whole lot more sense than Piola's image of last week.

As for the hydraulic pressures involved, myself and an inactive member made some draft calcs together and depending on piston areas involved, it should be somewhere between 100 and 200 Bar when activated, which is nothing in the context.

An issue however is the return stroke, where it might be useful to throttle that to avoid the nose coming down with a thump when the driver takes his foot off the brakes. This would mean dual lines, with entry to the pushrod cylinder by a check-valve and return through an orifice.

[FW17]

Can this not be done by locking the bell housing at the moment of breaking?

[xpensive]

Not sure what you mean by that W, but what I see above is the caliper being tangentially misaligned at rest, while tilting against the upright and compressing the master cylinder when activated and brake-torque is applied, bloody brilliant!

With the brake-torque being so high, at least 2500 Nm, the caliper should have no problems moving a 30 mm diameter plunge against 100 Bar, probably just a matter of pivot-geometry.

[FW17]

I understood this system as a compensation for the car squatting under braking.

the squatting is due to tyre compression and suspension dampers.

Lotus system probably can compensate for both, but locking the suspension during the initial braking phase (when the steering input is within certain limits) can be another way of partially achieving what lotus has set out to do.

[Ferraripilot]

I've been unable to find this information, but what I am searching for is who or what group at Lotus (or was it Renault at the time?) designed this. I'm reading that Bob Bell took one of the designers of the system from Renault some time ago, but I have no idea who, what their role was in designing the system, or when. And was Bell behind this at all while he was there?? I wonder