Mercedes AMG F1 W03 (pre-launch speculation)

[avatar]

Drag is felt at the wheels. All loads are not purely vertical. read the wording of the rule.
Height relatiosnhip between the COP and COG will also bring drag into play.

You need to look at the forces for what they are not for what you want to see

Hi Raptor

I think I need to clarify what I'm describing.
the load I'm talking about is not vertical at all, I'm currently looking purely at the deceleration felt within the car as a forward Gforce load, which activates the proposed system.

The rule I'm exploring (as it seemed to be the most contended) is:

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

I agree that the majority of the decelration force comes from forces acting at the wheels(brakes+ wheel/brake duct drag).

My contention is that the deceleration is at least in part caused by drag from the sprung car, acting horizontally, directly against the direction of travel.

My interpretation is that this constitutes a change in load applied to the device that did not come from the wheels.

The biggest criticism of this point ( that I've only just come up with, but so far no one else has pointed out) is that although the force on the mercury changed not due to braking forces at the wheels, the Aero force on the bodywork did not increase, so it's force did not change. It was infact the removal of forward force to enable the drag to slow the car that caused the change in force in the system.

Therefore, if you consider engine load to be applied only at the wheels, then I concede the point.

The only pure "not at the wheels forces" left that I can think of, which might contribute to activating the device without changing force at the wheels, only one of which I think may be a valid point against legality, are:
+ DRS disengagement increasing Aero drag independently of forces at the wheels - possibly valid
/ Pulling out of a Slipstream at point of braking, thus changing the Aero load and increasing drag - probably not valid
/ hitting someone in front of you very hard - not valid

I know I've been in a bit of a circle - I'm just trying to deduct any points that the FIA might moan about, but the DRS point may still be a problem.

[gato azul]

@avatar

sure all "forgiven "- no problem
I think, our difference in point of view about the "wording of the rule" revolves around, if you think that the reaction of the system needs to be "proportional" to any load/force at the wheel.
Or if it would be sufficient,to comply with the "wording of the rules" to have a change in load/force at the wheel.

I think [perhaps wrongly], that you tend to interpret the rules in the former way,
where I take them more "literally" and choose the later.

For this reason, I found it important to point out, that in an open wheeled car, a part for the drag(force), however large or small, comes/originates from the wheel(s).

And as Raptor22, IMHO correctly, points out, the rule don´t specify that it must be a change in "vertical" load.

Can aero drag (braking) have an effect on "vertical" tyre loads - I think it can quite easily.

If you may want to picture "aero drag" as a "parachute" and the point where you connect the parachute cord to the car as the "CoP", you will notice, that if this point, is significantly higher then the CoG [imagine a the parachute cord attached to the roll hoop] it will result in a backward pitch moment, while if it is connected significant lower, it will create a forward pitch moment.

This moment, can have an effect on the vertical loads on the wheels.

You may want to watch this video, and notice the movement of the nose wheel, when the parachute is deployed, even when in this case, the location of the parachute cord attachment, is chosen to minimize this effect on the plane, you will be still able to see an resulting motion.

@hardingfv32
not sure what is "interesting" in this, some high performance road cars, make use of this effect, to counter/reduce the "nose dive" effect which results from normal braking.

[avatar]

@gato azul

we crossed posts there I think.

The parachute analogy is a good one to highlight the flaw in my initial point.

If the car used a parachute attached to the sprung part of the car which only opened when slowing down, there would be a change in load, causing deceleration (and contributing to the device activating) that was independent of the load at the wheels.

In the case I outlined, there is no parachute opening. The force from drag remains constant(*) the load at the wheels has changed as forward force from the drive chain has been removed. The change in load was at the wheels, but was a removal of forward force, not an addition of braking force.

The DRS deactivation is effectively a parachute that only opens when the car is slowing down and does add drag, albeit with diminishing effect as the car slows down. This is a change in force not related to force at the wheels (in the forward-back direction I'm looking at) which will contribute a small portion of the load which activates the mercury system and affects the suspension.



(*) ignoring drag>speed relationship for now to shorten this bit

[hardingfv32]

What is interesting is that 'avatar' has found a force that does not always have to act on the wheels.... but activates the system and causes a response by the suspension. You can have a combination of pitch from deceleration balanced by the aero map to get a 'zero' load change at the wheel... and yet the system functions. Is this to be the one required exception to the rule or are there more?

Brian

[ForMuLaOne]

The DRS deactivation is effectively a parachute that only opens when the car is slowing down and does add drag, albeit with diminishing effect as the car slows down. This is a change in force not related to force at the wheels (in the forward-back direction I'm looking at) which will contribute a small portion of the load which activates the mercury system and affects the suspension.

EDIT: I wrote total bullshit there But DRS activation has an effect on tyre loads. The tyre loads decrease, as the added deceleration is caused by drag. The system would indeed react to a force that has its origin in the change of an aerodynamic device. But it is nevertheless a change in load applied to the wheels. There is simply no way for the FIA to forbid this system. Even if you talk about normal drag of the whole car, any change in speed will change wheel loads, as downforce changes.

[hardingfv32]

So, as long as the load on the wheels is changing, then anything is acceptable under this section of the rules. Since it could be argued that the design/construction of the tire creates internal loads/forces as it rolls, then this rule NEVER presents a restriction.

This contorted interpretation of this rule it is not a logical. This section has a purpose.

Can you describe a situation when, using your interpretation, that something might be found in breach of the 10.1.2?

Brian

[MercAMGF1Fans]

are we actually gonna talk about anything other than the suspension?

[ForMuLaOne]

So, as long as the load on the wheels is changing, then anything is acceptable under this section of the rules. Since it could be argued that the design/construction of the tire creates internal loads/forces as it rolls, then this rule NEVER presents a restriction.

This contorted interpretation of this rule it is not a logical. This section has a purpose.

Can you describe a situation when, using your interpretation, that something might be found in breach of the 10.1.2?

Brian

This would be every adjustment to the suspension. Active suspension, any change in lengths or stiffness, using magnetic oils which can change viscosity ( like the Audi magnetic ride system). Basically this article wants to forbid any system that has another source but the wheel loads for any respond You could use a lot of systems which can achieve a lot more than this. See the Lotus System for example changed the suspension system in advance, as the brakes hit before the wheels begin to turn slower. This means you had an adjustment BEFORE changes in wheel loads applied. The DRS is not in contact with the suspension, but before a system like the one we are talking about can response to aerodynamic change, there has to be a change in wheel loads in advance. Talking about a system that uses inertia force to work in any way means at the same time that it cannot work without any changes of conditions ( acceleration) of the frame (the chassis, the whole car) it is built in. They read the rule, came to the conclusion that inertia effects are always a RESULT of a change of conditions, and ( hopefully ) built a system that works TOTALLY in line with this article. You could say that building such a system means to take care of any accelerations a car can achieve, not only vertical, as you would think of first, but also, and in a perfect way, horizontal accelerations. Using any aero devices automatically changes the force resultants at the wheels, and AFTERWARDS the system responds.

[gato azul]

The DRS deactivation is effectively a parachute that only opens when the car is slowing down and does add drag, albeit with diminishing effect as the car slows down. This is a change in force not related to force at the wheels (in the forward-back direction I'm looking at) which will contribute a small portion of the load which activates the mercury system and affects the suspension.



(*) ignoring drag>speed relationship for now to shorten this bit

On an theoretical/conceptual basis, this is a very neat, well thought out argument Avatar.

But I feel, that in the cold light of reality in F1, a team would point out, that activation/deactivation of the DRS does not only changes drag in isolation.
More than drag, it will change downforce, as it is the "loss" in downforce, that leads to the reduction in drag from the DRS.

This change in downforce, will not only change the magnitude of vertical wheel load (downforce), but also it´s distribution, as the CoP will move backward or forward if DRS is activated/deactivated.

I´m sure, the teams would argue, that this clear change in vertical wheel load, when the DRS is used, would justify a response from the "Mercury System" and is perfectly within the "wording of the rules".

If you look at the L/D ratio in question, you would get a change of 2-2.7 units downforce, for every unit drag change.
Therefore, it could be argued, that the change in wheel load is much higher then the effect of the drag force on the Hg in the system.

[hardingfv32]

This would be every adjustment to the suspension. Active suspension, any change in lengths or stiffness, using magnetic oils which can change viscosity ( like the Audi magnetic ride system).

These all fail under other sections, not 10.1.2.

Basically this article wants to forbid any system that has another source but the wheel loads for any respond

YES, YES this is how the rule should be interpreted. Aero drag is the 'source' in this latest discussion, not the wheel. The wheels are possibly effected, but that is not required for the system to activate. This is how the 10.1.2 should be applied.

They read the rule, came to the conclusion that inertia effects are always a RESULT of a change of conditions, and....

In this case, the inertia effects are the RESULT of aero drag not wheel loads. Any wheel load changes in this example an the RESULT of aero drag. The fact that the wheel loads change does not make the system legal under this section.

Brian

[avatar]

See the Lotus System for example changed the suspension system in advance, as the brakes hit before the wheels begin to turn slower. This means you had an adjustment BEFORE changes in wheel loads applied.

If your interpretation of 10.1.2 is correct, then I think the Lotus system must have been banned under a different rule as the could simply have delayed activation using some form of blow out valve preventing activation below a given pressur, ensuring it actuated only after the load changed at the wheels.

The moveable aerodynamic device rule could ban the Lotus system on it's own IMHO though, but I never could understand why that rule banned the TMD but didn't ban wheel farings!

[ForMuLaOne]

These all fail under other sections, not 10.1.2.

You cannot exclude this article just as you like. Of course they fail under this section.

YES, YES this is how the rule should be interpreted. Aero drag is the 'source' in this latest discussion, not the wheel. The wheels are possibly effected, but that is not required for the system to activate. This is how the 10.1.2 should be applied.

The wheel itself will never be the source of any forces, it is the part where every force attacks. And the article only says that the response has to be a result of a CHANGE in wheel load. All that matters is, that before the system responds, you need to be able to measure a change in wheel loads.

In this case, the inertia effects are the RESULT of aero drag not wheel loads. Any wheel load changes in this example an the RESULT of aero drag. The fact that the wheel loads change does not make the system legal under this section.

[Raptor22]

Load at the wheels are a result of:

vertical loads i.e weight of the car, downforce, load transfer due to accelerations (positive or negative)

horizontal loads i.e. tyre adhesion to the tarmac as a result of chemical cohesive forces, rolling resistance.

Rolling resisitance can be unpacked into tyre deformation as a result of rolling and carrying a load + ahesive forces. These all act in a horizontal plane.

Drag force due to DRS, too much wing whatever, can all be resolved into load transfer as a result of deceleration that acts through the tyrs contect patch because;

1) it changes the net weight of the car proportionally to airspeed.
2) each tyre itself creartes drag and lift (through Coriolis Force of the tyre spinning. The latter is small but present, but results in a change of load at the wheels.

What is important to understand is that any aerodynamic force on the car can be broken up in to components of force that results in a change in load at the wheels.
In order to isolate the drag induced force yuou need very special circumstances

1) CG and CP on the same point in space within the car
2) assume perfectly solid, frictionless tyres to remove other horizontal loads to "0" (zero)
3) assume no load transfer due to deceleration.

I believe all three assumptions are outside the realms of reasonable interpretation, and practical implementation of a practical F1 race car.

Sure the FIA could ban anything they want, but in this devices case it won't be on scientific analysis of the system. It will purely be because they don't like people being too clever.
e.g. F-Duct, Fan Car, etc

Lotus system was banned because the design created a suspension member that was not solid from pivot to hub and the rules state that it has to be one piece solid without interruption. A hydraulic chamber linking the two members would be considered an interruption.

[swanracing]

I cant believe you guys are still talking about a possibly non existent system.

Can't this move to another thread? It's getting on my nerves, I don't bother to read the posts now as soon as I realise it's talking about the suspension I skip to the next post and the next and the next and the next, boring now!!

Any ideas other than the flipping suspension that may feature on the w03?

Now that a few cars have launched how do their wheelbases relate to the w02 are they all still longer?

[Raptor22]

http://abulafiaf1.wordpress.com/2012/02 ... on-part-a/