Post by markdg on Jan 4, 2008 8:44:08 GMT -7
This is from El Secundo. It runs counter to what I've always thought, that the CG should be as low as possible. But considering the source, it's definitely worth a shot.
The more grip you have, the lower you can add weight. The less grip you have, the higher it needs to be added. The ultimate goal is traction, and the common misconception is that a low center of mass equals high traction. This is not true.
Imagine a rubber block 4 feet tall. If you want to make it tip easily, you push it at the top of the block. If you want it to slide easily, you push it at the base of the block. But the block grips the most (and pushes back against you the most) when you're pushing the block somewhere in the middle. When you're adding weight, you're trying to find the optimum height where it pushes back the most.
Now, with a slot car, you're not getting any lateral grip from the front tires. Your only goal up front is to keep the front from tipping out of the slot. If you're going to add anything up front, add it low -- sliding up front is good, tipping is not.
So any weight added up high is going to be done near the back of the car.
If any of you have a Slot.It 956 that's loose, there's a nice place under the roof behind the driver for a strip of lead. This turned a Canon 956 from a quick car to a track record holder.
The optimum height for the weight depends on the grip you're getting, and the width of the rear track of the car. No matter where the weight is in the car, there will be an optimum level of grip. If your car is already sliding, tires with a higher coefficient of friction may provide the optimum grip for the current weight placement.
The more grip you have, the lower you can add weight. The less grip you have, the higher it needs to be added. The ultimate goal is traction, and the common misconception is that a low center of mass equals high traction. This is not true.
Imagine a rubber block 4 feet tall. If you want to make it tip easily, you push it at the top of the block. If you want it to slide easily, you push it at the base of the block. But the block grips the most (and pushes back against you the most) when you're pushing the block somewhere in the middle. When you're adding weight, you're trying to find the optimum height where it pushes back the most.
Now, with a slot car, you're not getting any lateral grip from the front tires. Your only goal up front is to keep the front from tipping out of the slot. If you're going to add anything up front, add it low -- sliding up front is good, tipping is not.
So any weight added up high is going to be done near the back of the car.
If any of you have a Slot.It 956 that's loose, there's a nice place under the roof behind the driver for a strip of lead. This turned a Canon 956 from a quick car to a track record holder.
The optimum height for the weight depends on the grip you're getting, and the width of the rear track of the car. No matter where the weight is in the car, there will be an optimum level of grip. If your car is already sliding, tires with a higher coefficient of friction may provide the optimum grip for the current weight placement.