Lotus's braking attitude compensator is now illegal

[timbo]

By way of demonstration, if the car is stationary then pushing the bake pedal will have no effect to this system (if my understanding is correct). So pushing the pedal does not control it directly.

Yep. Also, lifting a throttle at max speed gives about 1g deceleration. I wonder whether the system reacts on this.

[timbo]

Had a though, could the system be triggered by temperature rise in the brakes?
Would probably be a PITA to tune and also a tad lagging, but probably completely bulletproof legally.

[PlatinumZealot]

anyone else think Red Bull and their so called over the top rake might have been found out by Lotus?

i mean, a car pointing towards the ground is going to dig a hole under braking. however, we didnt see that from the RB's.

I think Lotus have seen the rake issue as an area to exploit and come up with this brilliant method

bravo Lotus

=D>

Hey man. That is an excellent point! Can somebody check if the RB6 and RB7 had a similar device?

[hardingfv32]

Had a though, could the system be triggered by temperature rise in the brakes

1) Heat as a signal for some other source of hydraulic force?

2) Or heat as a source of hydraulic forces? Say some kind of expanding fluid?

Does not sound precise enough to accurately correlate with the actual chassis motions.

Brian

[Shrieker]

Could we be looking at Lotus having a Brawn GP year, with Kimi at the helm? What a prospect!

Last year it was Heidfeld, this year it's Kimi... Come on guys

They'll be batling it out with Mercedes at best.

Otoh, the system looks promising in a place where tight regulations limit innovation. I can't see it providing a gain similar to DDD or ebd though.

[Richard]

No, because the driver pushing the break pedal has a primary legal function. If they just use the original modulation it would be perfectly legal.

I don't think the primary function comes into it. Otherwise you would have wings controlled by the throttle.

The fact that its controlled by the braking torque and not the master cylinder pressure means is reacting to the longitudinal dynamics of the chassis, not a driver input directly.

Tim

I agree with Tim, it has to work in exactly the same way as a suspension spring or damper compresses as a result of the car braking. I'd have thought a direct link from the pedal to suspension would be illegal.

[WhiteBlue]

I'd have thought a direct link from the pedal to suspension would be illegal.

Based on which § would you see such a device as illegal?

[beelsebob]

I'd have thought a direct link from the pedal to suspension would be illegal.

Based on which § would you see such a device as illegal?

3.15

[WhiteBlue]

I'd have thought a direct link from the pedal to suspension would be illegal.

Based on which § would you see such a device as illegal?

3.15

3.15 ....

With the exception of the parts necessary for the adjustment described in Article 3.18, any car system, device or procedure which uses, or is suspected of using, driver movement as a means of altering the aerodynamic characteristics of the car is prohibited.

3.15 is not applicable. That was reported in the Autosport article quoted in the opening post. That is the opinion of the FiA and I support it. The brake pedal is pushed for the primary purpose of reducing the speed. That cannot be illegal. All they do is exploiting the braking mechanism by adding another function.

If they had added another pedal that exclusively controls the attitude in order to compensate for dip - as James Allan thought - 3.15 would apply. You need to find another § to claim it is illegal.

[dren]

I posted this in the R32 thread as well. It is Honda's TRAC system used in the 80s on its motorcycles:

Here is a picture and my translation of the Japanese text. Luckily it "directly" translates to english so I only have to be able to spell it out.

1: Check Valve
2: Check Valve
The text in the middle on the right: Control Piston
Text at the bottom: Orifice Valve

So the caliper here actually physically moves upward when braking due to the rotational torque of the rotor. That pushes against the control piston which generates the needed hydraulic pressure to oppose the diving.

[Richard]

WB - what do you say about clause 10.1.2.

The system showed by Dren is what I described and complies with 10.1.2

10.1.2 The suspension system must be so arranged that its response results only from changes in load applied to the wheels.

[beelsebob]

That is the opinion of the FiA and I support it. The brake pedal is pushed for the primary purpose of reducing the speed. That cannot be illegal. All they do is exploiting the braking mechanism by adding another function.

Right – they're exploiting the braking mechanism – not the fact that the pedal was pressed. The two are causally linked, but not directly linked, which was the distinction made in the above post – note, they asserted that it would be illegal if they were directly using the break pedal – which renault are not.[/quote]

[timbo]

they asserted that it would be illegal if they were directly using the break pedal – which renault are not.

But that is what WB is suggesting.

[beelsebob]

they asserted that it would be illegal if they were directly using the break pedal – which renault are not.

But that is what WB is suggesting.

Right, what I was pointing out is that WB is asserting that the FIA have found a system directly controlled by the break pedal legal. They have not. They have found a system controlled by torque on the break callipers legal.

[WhiteBlue]

WB - what do you say about clause 10.1.2.

The system showed by Dren is what I described and complies with 10.1.2

10.1.2 The suspension system must be so arranged that its response results only from changes in load applied to the wheels.

That is an ambiguous formulation. I think they want to exclude aerodynamic forces to the unsprung masses by this.

What is the suspension system response? Is it a force, a frequency, an amplitude? It is rather undefined.

What is the load applied to the wheels? Is it the sum of all forces and torques? Is it the stress in the wheel as a result of the forces and torques? If yes how can this be defined for a particular wheel as the rule is written in the plural?

The Honda system also introduces a force to the suspension that is not generated by the wheel/tyre. The braking torque is generated by the breaking force and that force is not coming from the wheel, but from the braking cylinder.

I guess you have to go by the intention of the law to understand that the FiA allowed the device. To me the rule aims at making aerodynamic forces to the suspension illegal. IMO there are too many undefined terms in the rule to exclude the hydraulic devices that are now being discussed.

I still think that there is no difference to the legality of a system that uses rotary reaction from braking forces and a system that directly uses hydraulic pressure controlled some how by the brake pressure.