## C.O.G and weight distribution

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How is the C.O.G calculated of a F1 car??? and how does the driver's seating position affect that???

"Be the change that you wish to see most in your world" -- Mahatma Gandhi
mach11
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Joined: 21 Aug 2009
Location: India

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I would probably think that it's done in the exact same manner as calculating the COG of anything at all, sort of like a weighted average method. Just that it would be more complex seeing as it has so many components.

raymondu999
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Joined: 4 Feb 2010

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Tilt it in different directions until the car topples.

Then its simple trigonometry. Might seem unbelievable at the first instant but that is how 90% people measure the COG of their car in the professional racing.

Driver effects are quite simple, the problem is similar to calculation of change in COG due to addition of mass. The COG of driver really depends on his exact position.
IIT Bombay Racing
Vehicle Dynamics FSAE 08; FS 09
The_Man
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Joined: 15 Mar 2009
Location: Mumbai India

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I would think that you can get a very close estimate by modern solid-CAD modelling, such as ProE or SolidWorks.

The driver is a different matter though.
"Bernoulli is a nine-letter name"
xpensive
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Joined: 22 Nov 2008

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CG position longitudinally can be calculated by multiplying weight of single components and distance from a datum line (possibly front axle line)and adding up the moments of the components.
finally divide this by the total weight of the components and you arrive at the position of the CG .The more detailed your approach the closer you get to a realistic CG position.

As we have some pretty accurate figures for the main components, Fuel ,engine,driver,
gearbox,wheels etc it is quite a straightforward job to calculate were the actual CG position is.

Also it is obvious from this that not only the positioning of components in the car is the key to CG position but the ability to build a underweight car and position the ballast as low as possible ,and where you need it.

from 2009 to 2010 there was a significant change in rules implemented where the emphasis to loose weight in the front was a totally new aspect.so with less ballast placed in the front and having the main components are all placed above or around hub height (!)
marcush.
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Joined: 9 Mar 2004

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You can put a scale under each of your tire.
mep
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Joined: 11 Oct 2003
Location: Germany

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mep wrote:You can put a scale under each of your tire.

marcush.
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Joined: 9 Mar 2004

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mach11 wrote:How is the C.O.G calculated of a F1 car??? and how does the driver's seating position affect that???

I have no doubt at all that the mass & CofG of every component is known when it is designed. It is an easy task to locate all those elements in space and calculate the 3dimensional position of the CofG. More than that I would bet they know the MOI of each component and therefore the MOI of the car. I can't see why you wouldn't co-ordinate the design of each component into a central model so that as soon as one item is changed it's effect across the entire is known immediately.

As for the driver, his/her CofG is very important and obviously as a fairly sizable mass has a significant effect on the car. Surely it wouldn't be too hard to seat a driver in a fixed position and measure the CofG. Again, I wouldn't be at all surprised to find that some teams have a virtual model of their real drivers and they treat them as any other component in the design process.
RH1300S
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Joined: 6 Jun 2005

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I don't even think they design for centre of gravity.

I can't speak for the f1 teams but If I were designing an F1 car, think I would just make everything as low and as light as possible. When the design is done THEN I would just check what the Cog is, and if I can improve it later on, I just make the offending parts lower and lighter. That's how I would do it.
"I was blessed with the ability to understand how cars move," he explains. "You know how in 'The Matrix,' he can see the matrix? When I'm driving, I see the lines."
n smikle
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Joined: 12 Jun 2008

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It's natural to assume that every nut, bolt, and component planned for a car build is taken into consideration during the design phase. Then, once the car is finally constructed, then the numbers should match up. I do believe it is critical to allocate weight during the design process.

How do you find the center of gravity on any object? Hang it by a rope (or suitable cable). Take a photograph of it, and then change to another location to hang the car. Repeat, and where the two centerlines intersect, is the actual and true center of gravity.
A proud Canadian, and yes, HOCKEY is our game.
DaveKillens
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Joined: 20 Jan 2005

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I don't know about you, but if I was a team owner/boss I wouldn't want to hang my multimillion pound supercar on a rope/cable

raymondu999
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Joined: 4 Feb 2010

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raymondu999 wrote:I don't know about you, but if I was a team owner/boss I wouldn't want to hang my multimillion pound supercar on a rope/cable

You'll be surprised what people do. You can use a tilt table also. Its common practice to hand cars by ropes to find the Moment of Inertia anyway. Of course, this is done with some engineering sense not damaging the car.
IIT Bombay Racing
Vehicle Dynamics FSAE 08; FS 09
The_Man
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Joined: 15 Mar 2009
Location: Mumbai India

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n smikle wrote:I don't even think they design for centre of gravity.

I can't speak for the f1 teams but If I were designing an F1 car, think I would just make everything as low and as light as possible. When the design is done THEN I would just check what the Cog is, and if I can improve it later on, I just make the offending parts lower and lighter. That's how I would do it.

Why would they do that? If they designed everything to be as low as possible then everyone would be driving a pan-cake and lying flat in the car. It's CofG would be low, but compromised in other areas such as aero, geometry and packaging.

Of course they design with CofG in mind. To say they don't is like saying they build a car with no particular objective, when it's finished they check the CofG - then modify all the geometry to suit the CofG they seem to have discovered by accident.

The CofG location has a fundamental importance in the way a car uses it's tyres. Like everything else in the car the CofG height & location is about making choices and having design obejctives then setting out to achieve them.
RH1300S
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Joined: 6 Jun 2005

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of course CoGheight is of paramount importance...indeed it is the one and only reason for building the car underweight as much as possible.
Building the car underweight only opens the feasibility to go to extremes with the high nose concept ,where everything is placed on hub height..a very bad idea to start with in terms of weight transfer...
the high nose concept of course offers significant aero advantages with a better flow between the front tyres ,less convergence in this area ..enough to justify the
drawbacks with CoG height but just because of the placement of ballast in the splitter and not many heavy parts in the front of the car (drivers lower legs ,pedalbox steeringrack ,damper/rockers ,not much more to find there.So not too much ballast is needed to counter these drawbacks.
In effect the lighter the car the less you can gain by placing individual parts optimised for CoG height obviously .In an extreme world if you had half of the vehicle weight as ballast in the plank it would not mean much if you could find a possibility to mount your steering rack 10mm lower..
marcush.
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Joined: 9 Mar 2004

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actually saw this photo in the RB6 thread. Credits go to imightbewrong for the photo's original poster. Could this be a measuring of COG?!

raymondu999
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Joined: 4 Feb 2010

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