2000SForce

With all the battery talk that went down, what is better for track use making 50/50 or light weight

FixedWing

In order of priority:

1) reduce flywheel mass and unsprung mass
2) reduce overall mass
3) balance of car (i.e. weight distribution -- both front/rear and height of mass)
4) moving mass to the centre of mass of the car

Stephen

Disappear lika Ghost

according to who? :-)

FixedWing

Logically, #1 is a subset of #2. Since #1 has the additional benefit of reducing unsprung weight as well as reducing total mass then obviously #1 is preferable to #2.

Tyre grip is not linear based on weight. Ergo, a reduction of weight is more useful than a redistribution of weight. #2 beats #3.

moving mass towards the centre of mass will improve transient response of the car. It will do nothing to improve the overall limits of the car. Redistribution will improve the overall limits, again because tyre grip is not linear based on weight. So #3 beats #4.

:-p

Stephen

2000SForce

so why not center the battery in the trunk

FixedWing

The right-rear corner of the car.

This is assuming a LHD car and only a driver in the car. That's because the mass of the car is biased to the front-left of the car (front because the engine hangs off the front and left because the driver sits on the left).

So by moving mass to the right-rear it offsets the mass that is towards the left-front.

It would be nice if we could get all mass to sit closer to the centre of mass of the car but that's impossible on our cars because that area is reserved for passengers. So everything is placed at the edges of the car.

By the way, I have considered putting the battery under the hat shelf in the back for that very reason. It would be closer to the centre of mass of the car. But since it is not possible to do much about the mass of the engine or its position that doesn't make a lot of sense. Plus it would move the mass much higher up.

Now ... if our car was a rear-mid engined car driving the rear wheels with only the driver sitting in front of the engine and the wheels at the very corners of the car, then it would be a much more interesting car. A formula car is designed the way it is for balance and to have the shortest polar moment of mass possible (i.e. with the mass as close to the centre of mass as possible). :-)

Oh, the advantage of a short polar moment of mass is faster transient response. The car will start rotating (turn in) quicker and stop rotating quicker also. That also means it would spin faster as well if one were to make a mistake.

Stephen