Red Bull RB18

[godlameroso]

Perhaps the mechanical setup is built for oversteer, and the aero balance is built for understeer by having the COG and COP far rearwards.

With the front/rear weight balance defined by the rules (see my post above) the fore/aft position of c.g. is also defined. Moving the c.g. of a legal car rearwards would increase the rear weight and reduce the front weight making the car illegal if the tolerance of 0.440 front and 0.540 rear was exceeded. This doesn't leave much room for manipulation.

COG =/= weight distribution, COG is affected by where weight is placed, you can have weight distribution within regulations yet have different COG. This is because cars are not flat, they're 3 dimensional entities higher or lower placement of components affect COG.

Case in point, boxer engines change the COG vs an inline or V engine, even if they weigh the same because the boxer is low and wide it changes the COG vs an inline engine that has the mass concentrated in a smaller area.

The Tesla has good handling despite its massive curb weight because the COG is very low.

[AR3-GP]

45/55 split was put in place for Pirellis benefit, so they knew what weights would be on what corners.

The downforce far surpasses the weight of the cars and changes the weight distribution at speed. I'm not sure why Pirelli would think a static weight distribution helps them "know" anything.

[Tim.Wright]

COG =/= weight distribution, COG is affected by where weight is placed, you can have weight distribution within regulations yet have different COG. This is because cars are not flat, they're 3 dimensional entities higher or lower placement of components affect COG.

What you are speaking of here is CG-Height.

[Rodak]

COG =/= weight distribution, COG is affected by where weight is placed, you can have weight distribution within regulations yet have different COG. This is because cars are not flat, they're 3 dimensional entities higher or lower placement of components affect COG.

What you are speaking of here is CG-Height.

Correct. The discussion is about fore/aft c.g., shifting weight from front to back or vice versa. This is a shift in longitudinal c.g. which is different from vertical c.g. location. Obviously c.g. is a three dimensional locus for a solid object..... The regulations about fore/aft weight are for, obviously, fore/aft c.g.

[Stu]

From the 2022 Technical Regulations...

4.2 Mass distribution
With the car resting on a horizontal plane the mass measured at the front and rear axles must
not be less than the mass specified in Article 4.1 factored by 0.440 and 0.540 respectively at
all times during the qualifying practice session. Rounding will be to nearest 0.5kg.
If, when required for checking, a car is not already fitted with dry-weather tyres, its mass will
be determined using a set of dry-weather tyres selected by the FIA technical delegate

So there's no chance to move weight preferentially to either end of the car. Some of the discussion about ballast placement and c.g. refers to polar moment of inertia. By having the masses contributing to the c.g. closer to the c.g. that moment is reduced, allowing quicker response from steering inputs. You can have exactly the same c.g. position with weight at the ends as with the masses closer to the c.g.

I’ve read and re-read that regulation, but unless the scrutineering team are allowed to have the car presented with any random fuel mass (between 2.5-110kg), teams only need to have that weight distribution during sessions when the car may be weighed/checked. This would be all sessions other than the race itself, giving the potential to have a different weight distribution when full of fuel. Could an advantage be gained early doors during the race by doing this?

[schwepes]

COG is only one part of the story. Mass distribution contributes also to the moment of inertia, which also affects vehicle behavior*, and you can play with the different moment of inertia within the same COG limit.

*In principle lower inertia makes the vehicle more "agile", while higher gives more high speed stability

[Vanja #66]

You ever lift throttle oversteer on an old 911? It doesn't rotate so much as simply swap ends. That's an extreme example. In general terms, the car pivots around the COG correct? COP should induce oversteer at low speed, forward of COG, and migrate towards COG for a neutral but oversteery high speed, personal preference. It's probably faster to have the COP behind the COG, but that might be what triggers the porpoising.

One thing I heard LeClerc mention, is how he has to use the throttle to steer the Ferrari. Perhaps the mechanical setup is built for oversteer, and the aero balance is built for understeer by having the COG and COP far rearwards. Chassis compliance + aero forces create a springboard effect? Not sure, would be interesting to get some data to analyze.

To be honest, we need to align on the "neutral" CoG position first before we continue the fore-aft dicussion. Is it 50-50, 45-55, 40-60? Joking aside, I understand what you meant here and I agree, but moving the CoG too far rear is good for traction but unloads the front way too much and at some point. So as you suggested, towards the rear a bit, but not too much. As for CoP, it moves forward with braking comapred to its natural position (I'd say this applies to all race cars, but open-wheel cars definitely), but in general you want it rear of the CoG to prevent oversteer on corner exit ("throttle steering" at the wrong time). Car pitching up on throttle tends to help with that. How nice...

[Just_a_fan]

As for CoP, it moves forward with braking comapred to its natural position (I'd say this applies to all race cars, but open-wheel cars definitely),

As a brief aside, a number of road cars use active rear aero devices to counter this. It started, I think, with the F1 which had a small device that flicked up when braking. This did two things - opened a channel to allow air to cool the rear brakes, and also move the CoP rearwards to give stability - something very important on a 200mph++ road car potentially driven by unskilled drivers. Murray said that it was necessary because the relatively soft suspension they ran on the F1 meant the CoP moved a long way under hard braking.

A number of cars have used similar devices since, some even using them to give real aerodynamic braking e.g. the Veyron.

[Zynerji]

45/55 split was put in place for Pirellis benefit, so they knew what weights would be on what corners.

The downforce far surpasses the weight of the cars and changes the weight distribution at speed. I'm not sure why Pirelli would think a static weight distribution helps them "know" anything.

Doesn't matter. Look at when it was put in the rules, and the reasoning. It was to "help" Pirelli make F1 tyres for the first time.

[Mchamilton]

From the 2022 Technical Regulations...

4.2 Mass distribution
With the car resting on a horizontal plane the mass measured at the front and rear axles must
not be less than the mass specified in Article 4.1 factored by 0.440 and 0.540 respectively at
all times during the qualifying practice session. Rounding will be to nearest 0.5kg.
If, when required for checking, a car is not already fitted with dry-weather tyres, its mass will
be determined using a set of dry-weather tyres selected by the FIA technical delegate

So there's no chance to move weight preferentially to either end of the car. Some of the discussion about ballast placement and c.g. refers to polar moment of inertia. By having the masses contributing to the c.g. closer to the c.g. that moment is reduced, allowing quicker response from steering inputs. You can have exactly the same c.g. position with weight at the ends as with the masses closer to the c.g.

I’ve read and re-read that regulation, but unless the scrutineering team are allowed to have the car presented with any random fuel mass (between 2.5-110kg), teams only need to have that weight distribution during sessions when the car may be weighed/checked. This would be all sessions other than the race itself, giving the potential to have a different weight distribution when full of fuel. Could an advantage be gained early doors during the race by doing this?

Regulation says they only have to meet that number during qualifying. So once the car enters parc ferme basically, from then on it has to conform to all the regulations doesnt it.
They get called to the weigh bridge after runs dont they, which is the point at which the car will be at its lowest fuel.
Theres also a section in the sporting regs about the cars being weighed too

[Rodak]

Regulation says they only have to meet that number during qualifying. So once the car enters parc ferme basically, from then on it has to conform to all the regulations doesnt it.
They get called to the weigh bridge after runs dont they, which is the point at which the car will be at its lowest fuel.
Theres also a section in the sporting regs about the cars being weighed too

Not so. Here's the regulation re weight... note the phrase 'at all times during the competition' meaning during practice, qualifying, and race.

4.1 Minimum mass
The mass of the car, without fuel, must not be less than 775Kg at all times during the
Competition.
If, when required for checking, a car is not already fitted with dry-weather tyres, its mass will
be determined using a set of dry-weather tyres selected by the FIA technical delegate.

[godlameroso]

The COG and weight distribution are not the same thing, the COG is a calculated point that will balance the car. The weight distribution is calculated by corner weights. Where the car is naturally balanced is partly determined by the corner weights, where mass is concentrated makes a bigger difference regarding that balance. Once the COG is set, it doesn't move much, even in a dynamic sense, what does change however is the aero balance. The floor is particularly sensitive to AoA so if the floor yaws, pitches, bounces or changes in rake, that COP is going to move around.

Red Bull trialed new front wing endplates, and new rear wing end plates, and Verstappen was complaining about the balance all weekend. With how setup sensitive the cars have become, perhaps getting the updates to work will take a little while longer because it requires more adaptation from the driver.

[AR3-GP]

The CoG is a 3D coordinate. It defines everything (the CG height, and the weight distibution based on the distance between the CoG and the front and rear tires).

[vorticism]

The spec weight distribution is considered as a factor of total minimum dry weight. This means the weight distribution with fuel and driver is not regulated. That's how I read it.

That being the case, it would be possible to alter fuel mass centers.

-Mass center(s) shifting as fuel is consumed
-Mass center(s) shifting during pitch, heave, yaw, and lateral acceleration

Fuel mass may be the last frontier as it relates to mass dampening.

Given that only RB is struggling with fueling issues while struggling the least with porpoising, we might speculate that they are using the fuel tank as a means to quell porpoising, in addition to their aero or suspension design.

Such systems may have compatibility issues with the evaporative nature of ethanol.

[Rodak]

The COG and weight distribution are not the same thing, the COG is a calculated point that will balance the car. The weight distribution is calculated by corner weights.

The location of the c.g. (actually center of mass) determines the weight distribution on the front/rear. For example, consider a car with a wheel base of 100 whatevers and a mass of 100 whatevers. If the c.g. is at 50 the car would balance on a knife edge at 50. The fore/aft weights would be 50/50. If the c.g. was moved so it was over the rear axle (this is of course imaginary for simplicity sake) the c.g. would be at 0 and the rear weight 100; the front weight would be 0. Move the c.g. to 45 and the rear weight would be 55, the front 45, which is what the regulations require ±. Now how do you change the fore/aft weights without moving the c.g. or vice versa? You can't. This is pretty basic stuff.....

To clarify whether the regulations apply during the entire meeting, here is Article 2 of the Sporting Regulations...

2) GENERAL UNDERTAKING
2.1 All drivers, Competitors and officials participating in the Championship undertake, on
behalf of themselves, their employees, agents and suppliers, to observe all the
provisions as supplemented or amended of the International Sporting Code (the Code),
the Formula One Technical Regulations (Technical Regulations), the Formula One
Financial Regulations (Financial Regulations) and the present Formula One Sporting
Regulations together referred to as “the Regulations”.
2.2 The Championship and each of its Events is governed by the FIA in accordance with the
Regulations.
2.3 Event means any event entered into the FIA Formula One Championship Calendar for
any year commencing four (4) hours before P1 is scheduled to start and ending at the
time for the lodging of a protest under the terms of the Code or the time when a technical
or sporting certification has been carried out under the terms of the Code, whichever is
the later.