Mercedes AMG F1 W03 (pre-launch speculation)

[hardingfv32]

In this case, as others noted, it will depend on the location of the the CoP (in vertical [z] axis)if you see a change in vertical wheel loads, due to pitch moment around the CoG or not.

So, your position is that aero drag causes the load to change at the wheels in some cases. Is that correct? Interesting

Brian

[hardingfv32]

How do you convince the FIA that the system was only activated by the other 5G caused by braking force at the wheels and not at all affected by the 1G aero braking force applied to the sprung car?)

How and under what rule does this statement have relevance? I do not understand how it is useful to the legality question.

Brian

[avatar]

How do you convince the FIA that the system was only activated by the other 5G caused by braking force at the wheels and not at all affected by the 1G aero braking force applied to the sprung car?)

How and under what rule does this statement have relevance? I do not understand how it is useful to the legality question.

Brian

The contention I've read most often around this device is whether other not it's affect on the suspension is driven only by force applied at the wheels.

If 1/6th of the G-force in a Max braking event is attributed to Aero, then 1/6th of the force activating the system which alters suspension is applied to the sprung car, not applied at the wheels.

*edit 2*
To have it declared legal, I think you'd have to convince the FIA that *only* the 5/6ths braking force applied at the wheel was activating the system & I can't see how to argue that case...
*/edit2*

I can't remember the rule number, but it's been frequently quoted in this discussion.

*edit*
found it:
10.1.2, "The suspension system must be so arranged that its response results only from changes in load applied to the wheels."

[Lurk]

If you release throttle and your car start to slow down, shouldn't downforce decrease? suspension will react to that and the car will go upper, clever ride height system or not.
FIA would not be able to tell if the car go up because of the system or because of the decrease of downforce.

The only thing you have to do is built a system that react fast enough to not be able to tell if the suspension react only to the wheel load change or not, and which cannot be activated while car is static.

LRGP one was easy to spot and to ban since it was clearly linked to the brake system and you just had to press the pedal to see the system react.

[gato azul]

Nothing is wrong with the diagram and its context.

Not sure, where you live in the "universe", maybe in a place where Power = Force x Distance [which would explain Brian´s affection for your comments], but on "Earth" the changes in loads on the wheels of a car on an slope would be governed by the following:




FN (aka Normal Force), would be what you like to call "weight", and what you would measure, when you put some scales under the wheels of the car.

In the example above, the sum of all scales would read 8.7N (or 0.866 kg in your world), where the same scales on a flat road would read a value of 1 kg.
Please note, that in the above example FG is rounded to the nearest integer (10) it can be written with greater accuracy as 9.81N for a mass of 1 kg.

I guess for most people, perhaps including Charlie Whiting, the change from 1kg (9.81N) to 0.866kg (8.7N), for FN in the example above, could be considered as an "change of loads at he wheel".

P.S.: Maybe you would like to explain, why the length of the arrow under the front wheel, in your diagram changes length, assuming it was meant to indicate the magnitude of FN or "weight" under this wheel.
But maybe you live in an universe, where load under the tyre, is depending on spring rate as well.

[gato azul]

If 1/6th of the G-force in a Max braking event is attributed to Aero, then 1/6th of the force activating the system which alters suspension is applied to the sprung car, not applied at the wheels.

You assume, in your statement, that all the aero drag is generated by the sprung part (body, wings etc.), and that the wheels don´t contribute to aero drag.
I´m not too sure, if this assumption is entirely correct for a open wheel race car.

Somehow, I was under the impression, that the "open wheels" of an F1 car, are contributing a significant amount to it´s overall drag, compare to an LMP car for example.

BTW:
I could not care less, if this proposed system is illegal or not, just taking "offense" with some statements made here, to prove that it is illegal,because, some
of these statements are in violation of some fundamental principles.

[avatar]

If you release throttle and your car start to slow down, shouldn't downforce decrease? suspension will react to that and the car will go upper, clever ride height system or not.
FIA would not be able to tell if the car go up because of the system or because of the decrease of downforce.

It's not so much whether the suspension dips or not, but that the suspension action has been affected by force that was not applied at the wheels.

From memory, the TMD was banned without being it's action being measured. (can anyone confirm whether that's right?)

If the FIA ask for an explanation of this device as I believe they're entitled to, and they're told what has been described here, then they *may* not be satisfied for one or more of the points being discussed.
Of course, a team can always lie to the FIA about a device's true function(*).and if they're satisfied with the alternative function, they may allow it. However, other than affecting the suspension as we've been discussing, I can't see an excuse for this device being on the car, particularly as it's coupled with the suspension.


(*) an extreme example was the fan on the fan car being for cooling, not d/f

[avatar]

If 1/6th of the G-force in a Max braking event is attributed to Aero, then 1/6th of the force activating the system which alters suspension is applied to the sprung car, not applied at the wheels.

You assume, in your statement, that all the aero drag is generated by the sprung part (body, wings etc.), and that the wheels don´t contribute to aero drag.
I´m not too sure, if this assumption is entirely correct for a open wheel race car.

Somehow, I was under the impression, that the "open wheels" of an F1 car, are contributing a significant amount to it´s overall drag, compare to an LMP car for example.

BTW:
I could not care less, if this proposed system is illegal or not, just taking "offense" with some statements made here, to prove that it is illegal,because, some
of these statements are in violation of some fundamental principles.

I assume no such thing. In one of my earlier posts I mentioned the unsprung parts ("wheels and brake duct gubbins " plus suspension arms etc.) of the car causing a portion of overall drag but they certainly don't cause all of it. The figures I used are just an illustration as I don't have access to any real world data.

For my point not to apply, all of the drag would need to come from the unsprung car and none of it from the sprung parts. Even if half of the deceleration due to drag were soley down to unsprung parts, using my illustrative numbers as that's the best I've got, 1/12th of the G-force activating the system would be down to force applied to the sprung car.

I don't know what fundamental principal that brakes, nor do I see reason to take offence; I've merely been exploring the cases for and against, starting from a neutral viewpoint and ending up leaning towards the FIA having a problem with the device.

But let's face it; the device is hypothetical. Any stance the FIA may take is also hypothetical.

I see no reason to take offence at what I wrote, and I choose not to take offence at your comment that implies I have violated a fundemental principal as I know you're unlikely to (as its perfectly reasonable not to have done, given the length of the discussion thus far) have read every word of the posts I've made.

[gato azul]

I assume no such thing. In one of my earlier posts I mentioned the unsprung parts ("wheels and brake duct gubbins " plus suspension arms etc.) of the car causing a portion of overall drag but they certainly don't cause all of it. The figures I used are just an illustration as I don't have access to any real world data.

For my point not to apply, all of the drag would need to come from the unsprung car and none of it from the sprung parts. Even if half of the deceleration due to drag were soley down to unsprung parts, using my illustrative numbers as that's the best I've got, 1/12th of the G-force activating the system would be down to force applied to the sprung car.

I don't know what fundamental principal that brakes, nor do I see reason to take offence; I've merely been exploring the cases for and against, starting from a neutral viewpoint and ending up leaning towards the FIA having a problem with the device.

But let's face it; the device is hypothetical. Any stance the FIA may take is also hypothetical.

I see no reason to take offence at what I wrote, and I choose not to take offence at your comment that implies I have violated a fundemental principal as I know you're unlikely to (as its perfectly reasonable not to have done, given the length of the discussion thus far) have read every word of the posts I've made.

@avatar

Apologize, I did not took "offense " [I hope adding a smile, to the word "offense" makes it´s meaning in this context clear], in your general point - far from. The last part of my post was not aimed at you, or a response to what you wrote.
Nevertheless, I do think, that your statement, and that is what I quoted and referred to, that if 1/6th of the overall braking performance is attributed, to aero drag, then 1/6th of the forces reacted to by the system come not from the wheel, is not correct)
Now you took 1/6th and made it 1/12th, which is a different statement altogether - IMHO.
Because, now you state very clearly, that even if we consider aero drag, there will be a part of it acting on/at the wheel, origin at the wheel, as the wheel will cause part of the drag(force).
[if the contribution is x% or y%, we will not know for sure, without data, but there is a fraction of this force/load originating at the (front) wheels]

Which I think, is important to note, in this context.

[Tyler]

just a comparison between the photoshop i did 2 weeks ago, and the vjm05. there is some likeness. what do you think?

Yup, it's like you inadvertently drew the FI - looks very similar.
I'm expecting the Merc to have this same kind of look but guess we'll have to wait and see

[Raptor22]

Is the response in the mercury Inertial hydraulics suspension only derived from the wheel load?

Ooh.

Decelleration due to Aero drag when lifting throttle at full speed....

...doesn't that provide significant braking purely from Aero, which, other than he wheels and brake duct gubbins is *all* acting on the unsprung car, not the wheels.

I don't know the figures for Aero braking on an F1 car, but if the system activated are or below the possible force from Aero braking, it should probably be illegal.

Add to that the DRS disengagement adding back a load of drag back (thus decelleration force not applied at the wheel) at the point of breaking, and I can't see it being justified.

What do you reckon?

It depends where the CoG is in relation to the Centre of pressure for the car.
Any drag force will have a couple with the statics and dynamics properties of the car.
Another thing to sonsider is drag is proportional to velocity and the drag coefficient of the car. At what point would the forces balance to reduce the couple

you need actual data an this is a problem that would be considered during the design of the car

Wikipedia is suggesting Martin Brundle from a few years ago stating 1G for standard Aero drag braking effect, but I can't find any figures for G-force attributed to DRS disengaging (I.e.flap closing).

Basically I think you're saying that the system would have to remain inactive at 1G plus any additional force from DRS disengaging.

I'm not sure you can remove the Aero braking from the equation.
Ignoring DRS due to lack of figures, if say Max braking force is 6G, 1G of that will be due to drag.

How do you convince the FIA that the system was only activated by the other 5G caused by braking force at the wheels and not at all affected by the 1G aero braking force applied to the sprung car?

In simplistic terms you could attribute 1/6th of the force activating the system and affecting the suspension to drag induced deceleration.

I agree it's still a judgement call on the part of the FIA, but given their form on clever suspension control like the Lotus system and the TMD, I fear the worst!

[/quote]


How do you convince the FIA?
YOu design the car in such a way that forces acting through the CoP and forces acting through the CoG are in the same plane and close together to eliminate any significant coupling.
You account for the CoP forces when you design the threshold of the cut-in for the inertia mercury system.
The legality is merely a mathematics and engineering design problem.
But why would I be concerned if this cannot be measured under scrutineering?

What is far more interesting is the possibilities the system opens up.

[avatar]

@avatar

Apologize, I did not took "offense " [I hope adding a smile, to the word "offense" makes it´s meaning in this context clear], in your general point - far from. The last part of my post was not aimed at you, or a response to what you wrote.
Nevertheless, I do think, that your statement, and that is what I quoted and referred to, that if 1/6th of the overall braking performance is attributed, to aero drag, then 1/6th of the forces reacted to by the system come not from the wheel, is not correct)
Now you took 1/6th and made it 1/12th, which is a different statement altogether - IMHO.
Because, now you state very clearly, that even if we consider aero drag, there will be a part of it acting on/at the wheel, origin at the wheel, as the wheel will cause part of the drag(force).
[if the contribution is x% or y%, we will not know for sure, without data, but there is a fraction of this force/load originating at the (front) wheels]

Which I think, is important to note, in this context.

You're correct that the terminology was wrong.

If I added, the word "sprung car" before Aero braking/drag, would you forgive me?

Like I said, the figures are just representations rather than accurate figures, I think we both we agree it could be 1/6th, 1/12th or another portion of braking that is down to sprung car, but some portion is.

That being the case, some degree of force not applied at the wheels is contributing to it affecting the suspension, which could mean a ban (if the device does exist).

[Raptor22]

@avatar

Apologize, I did not took "offense " [I hope adding a smile, to the word "offense" makes it´s meaning in this context clear], in your general point - far from. The last part of my post was not aimed at you, or a response to what you wrote.
Nevertheless, I do think, that your statement, and that is what I quoted and referred to, that if 1/6th of the overall braking performance is attributed, to aero drag, then 1/6th of the forces reacted to by the system come not from the wheel, is not correct)
Now you took 1/6th and made it 1/12th, which is a different statement altogether - IMHO.
Because, now you state very clearly, that even if we consider aero drag, there will be a part of it acting on/at the wheel, origin at the wheel, as the wheel will cause part of the drag(force).
[if the contribution is x% or y%, we will not know for sure, without data, but there is a fraction of this force/load originating at the (front) wheels]

Which I think, is important to note, in this context.

You're correct that the terminology was wrong.

If I added, the word "sprung car" before Aero braking/drag, would you forgive me?

Like I said, the figures are just representations rather than accurate figures, I think we both we agree it could be 1/6th, 1/12th or another portion of braking that is down to sprung car, but some portion is.

That being the case, some degree of force not applied at the wheels is contributing to it affecting the suspension, which could mean a ban (if the device does exist).

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

[avatar]

How do you convince the FIA?
YOu design the car in such a way that forces acting through the CoP and forces acting through the CoG are in the same plane and close together to eliminate any significant coupling.
You account for the CoP forces when you design the threshold of the cut-in for the inertia mercury system.
The legality is merely a mathematics and engineering design problem.
But why would I be concerned if this cannot be measured under scrutineering?

What is far more interesting is the possibilities the system opens up.

Don't get me wrong, I like the concept, but I also liked the TMD concept & I think they FIA banned that without measurement.

I've not been considering CoP or CoG in depth, but I think, and correct me if I'm wrong as I'm really not sure, that you're suggesting CoG and CoP would be used to keep the ride height under sprung-aero-drag-induced-deceleration?

IMHO this could indeed be used to mask the effect it was having, but that drag is still causing deceleration, therefore contributing a portion of the pressure in the system when it activates.

I think you're correct you could hide it quite effectively, but as far as I know the FIA can ask for explanations of any part of the car to check for legality...

[hardingfv32]

IMHO this could indeed be used to mask the effect it was having, but that drag is still causing deceleration, therefore contributing a portion of the pressure in the system when it activates.

This is absolutely the correct analysis. With this system the suspension is responding to aero drag not wheel loads. It is not necessary for the wheels to be affected by the change on aero loads for the system to function.

Brian